HomeMy WebLinkAbout2025-083-09/16/2025-AUTHORIZING THE CITY MANAGER TO EXECUTE AN AGREEMENT WITH THE COLORADO WATER CONSERVATION BOARD FORRESOLUTION 2025-083
OF THE COUNCIL OF THE. CllY OF FORT COLLINS
AUTHORIZING THE CITY MANAGER TO EXECUTE AN
AGRE EMENT WITH THE COLORADO WATER CONSERVATION
BOARD FOR PROTECTED MITIGATION RELEASES FROM THE
HALLIGAN WATER SUPPLY PROJECT
A.The City owns and operates a water utility that provides water service to
customers i.n its service area. Through the water utility, the City is pursuing the Halligan
Water Supply Project ("Halligan Project"). The Halligan Project will provide additional firm
yield for the City's water utility, in addit ion to various ot�er benef its.
B.The Halligan Project primarily entails enlarging the existing Halligan
Reservoir by 8,200 acre-feet. Once operational, the City will stor� water under its water
rights ("City Water") in the enlarged Halligan Reservoir and make releases into the North
Fork of the Cache la Poudre River ("North Fork") below Halligan Dam. The City Water
will float these releases down about 22 miles of the North Fork to the confluence with the
main stem of the Cache la Poudre River at Gateway Natural Area. The City will then
generally divert a like amount of water into its pipelines located just upstream.
C.Pursuant to Colorado Revised Statute ("C.R.S.") Section 37-60-122.2, the
State of Colorado, through the Colorado Parks and Wildlife Commission and the Colorado
Water Conservation Board ("CWCB"), has adopted the Halligan Water Supply Project:
Fish and Wildlife Mitigation and Enhancement Plan, dated June 7, 2023 ("Mitigation
Plan"), as the official state position on the mitigation actions required of the City for the
Halligan Project.
D.Pursuant to the Mitigation Plan, the City will attempt to protect its releases
of the City Water from the enlarged-Halligan Reservoir ("Halligan Releases") under C.R.S.
§37-92-102(8) by seeking a decree from the Water Court. S1.1ch a decree would generally
not allow others· to divert, exchange upon, or use the Halligan· Releases between the
enlarged Halligan Reservoir Dam and Milton Seaman Reservoir if that were to cause a
reduction in the Halligan Releases. See C.R.S. § 37-92-102(8)(c)(II). To proceed
seeking such a decree, the City must enter into an agreement with the CWCB to dedicate
the reservoir releases to the CWCB. See.C.R.S. § 37-92-102(8)(d)(I).
E.The City and the CWCB have negotiate d a Water Dedication and Delivery
Agreement ("Agreement") for the dedication of such reservoir releases of City Water from
the enlarged Halligan Reservoir to the CWCB, a copy of which is attached hereto and
incorporated by reference, as Exhibit A.
F.Under the Agreement, the City would retain ownership of all of the City
Water associated with the reservoir releases from the enlarg'ed Halligan Reservoir. The
Agreement would not alter the City's planned operations of the enlarged Halligan
Reservoir, including with respect to the City's yield from the Halligan Project or the
environmental benefits of the project.
-1-
G.Entering into the Agreement is in the best interests of, and will benefit the
City and its citizens because it will further the Halligan Project and its various benefits, it
will further the goal of preserving and improving the ecological,, environmental,
recreational, sociological, and other resources benefitted by Poudre River flows, and
while imposing few, if any, costs on the City as discussed herein.
H.The City Water associated with the reservoir releases from the enlarged
Halligan Reservoir is part of the City's water utility system, but its use under the
Agreement will not materially impair the viability of the water utility system as a whole and
will be for thE;l benefit of the citizens of the City.
I.No compensation is to be paid to the City under the Agreement, but the
Agreement would serve a bona fide public purpose because:
(1)The use to which the City Water will be put under the Agreement promotes
health, and general welfare and benefits a significant segment of the
citizens of Fort Collins;
(2)The use to which the City Water will be put supports one or more of the City
Council's goals, adopted policies,. projects or plans;
(3)The financial support provided by the City through. the below-market
disposition of the rights in the City Water will be leveraged with other funding
or assistance associated with the Halligan Project;
(4)The Agreement will not result in any direct financial benefit to any private
person or entity, except to the extent such benefit is only an incidental
consequence and is not substantial relative to the public purpose being
served; and
(5)The Agreement will not interfere with current City projects or work programs,
hinder workload. schedules or divert resources needed for primary City
functions or responsibilities.
In light of the foregoing recitals, which the Council hereby makes and adopts as
determinations and findin gs, BE IT RESOLVED BY THE COUNCIL OF THE CITY OF
FORT COLLINS as follows:
Section 1. City Council finds, pursuantto Section 23-1 t1 (a) of the City Code,
that the disposition of certain rights associated with the City Water pursuant to the
Agreement is in the best interests of the City.
Section 2. • City Council finds, pursuant to Section 23-111 (b) of the City Code,
that the disposition of certain rights associated with the City Water pursuant to an
agreement that is substantially similar to the Agreement will not materially impair the
viability of the water utility system as a whole and that it will be for the benefit of the
citizens of the City.
-2-
Section 3. City Council finds, pursuant to Section 23-114, that the disposition of
certain rights associated with the City Water pursuant to the Agreement may be for an
amount less than market value, but that it would serve a bona fide public purpose for the
reasons set forth above.
Section 4. The City Manager is hereby authorized to execute the Agreement in
the form of Exhibit A, attached hereto and incorporated by this reference, with such
modifications and additional terms and conditions as the City Manager, in consultation
with the City Attorney, determines to be necessary and appropriate to protect the interests
of the City or effectuate the purposes of this Resolution.
Passed and adopted on September 16, 2025.
ATTEST:
Effective Date: September 16, 2025
Approving Attorney: Eric Potyondy
Exhibit: Exhibit A -Water Dedication and Delivery Agreement
-3-
Page 1 of 12
WATER DEDICATION AND DELIVERY AGREEMENT
(Halligan Water Supply Project – Protected Mitigation Releases)
The Colorado Water Conservation Board (“CWCB”), an agency of the State of Colorado,
and the City of Fort Collins, a municipal corporation of the State of Colorado with home-rule
authority (“Fort Collins”), each a “party” and collectively the “parties,” in consideration of the
mutual promises contained herein, agree as follows:
RECITALS
A.The CWCB is an agency of the State of Colorado created to aid in the protection and
development of the waters of the state for the benefit of its present and future inhabitants.
In 1973, the Colorado General Assembly vested the CWCB with the exclusive authority
to appropriate waters of the natural stream for minimum stream flows between specific
points on a stream to preserve the natural environment to a reasonable degree.
B.Pursuant to Section 37-92-102(3), C.R.S., the Colorado General Assembly has also vested
the CWCB with the ability to acquire water, water rights, or interests in water that are not
on the Division Engineer’s abandonment list in such amounts as the CWCB determines
are appropriate for stream flows to preserve or improve the natural environment to a
reasonable degree.
C.Pursuant to Section 37-92-102(8), C.R.S., the owner of a water storage right that allows
water from the right to be stored in New Reservoir Capacity0F
1 may acquire the decreed
right to make, and obtain protection for, Protected Mitigation Releases of water from that
New Reservoir Capacity into a Qualifying Stream Reach, up to the amount of water that
is appropriate for stream flows to preserve or improve the natural environment to a
reasonable degree within the Qualifying Stream Reach, and to reasonably avoid,
minimize, or mitigate the impacts of the New Reservoir Capacity on fish and wildlife
resources within the Qualifying Stream Reach, to comply with a fish and wildlife
mitigation plan approved under Section 37-60-122.2, C.R.S. To make such Protected
Mitigation Releases, the owner of the water storage right is required to:
i.dedicate the proposed Protected Mitigation Releases to the CWCB;
ii.agree to make the proposed Protected Mitigation Releases available for use by the
1 This Agreement uses certain capitalized terms as those terms are defined in Section 37-92-102(8)(b), C.R.S. If not
defined in Section 37-92-102(8)(b), other capitalized terms have been specifically defined in this Agreement.
EXHIBIT A TO RESOLUTION 2025-083
Page 2 of 12
CWCB within the Qualifying Stream Reach;
iii. file an application in water court, with the CWCB as a co-applicant, seeking
approval of the proposed Protected Mitigation Releases; and
iv. obtain a decree approving the Protected Mitigation Releases.
Except as provided in Section 37-92-102(8)(e), C.R.S., the dedication to the CWCB is
subject to Section 37-92-102(3), C.R.S., including the requirement that the CWCB find that
the proposed Protected Mitigation Releases are appropriate to preserve and improve the
natural environment to a reasonable degree within the Qualifying Stream Reach.
D. Fort Collins is currently pursuing the permitting, design, and construction of an
enlargement for the existing Halligan Reservoir located on the North Fork of the Cache
la Poudre River (“North Fork”). This enlargement project is referred to in this Agreement
as the “Halligan Project.” The Halligan Project is a water supply project that primarily
entails the enlargement of Halligan Reservoir by means of the construction of a
replacement dam for the existing Halligan Reservoir dam.1F
2 Fort Collins will use the
additional New Reservoir Capacity created by the enlargement of Halligan Reservoir
(“Halligan New Reservoir Capacity”) for storage of the Halligan Mitigation Release
Rights (as defined in Recital E). Once released from storage in the Halligan New
Reservoir Capacity and rediverted below the Halligan Qualifying Stream Reach (as
defined in Recital H), water attributed to the Halligan Mitigation Release Rights will be
used by Fort Collins for a variety of municipal and other decreed uses to provide
additional water supplies to Fort Collins’ water customers and to satisfy Fort Collins’
projected municipal and other water demands. As part of the Halligan Project, Fort
Collins will also replace and/or rebuild the existing North Poudre Canal diversion
structure located on the North Fork between Halligan Reservoir and Milton-Seaman
Reservoir to allow for the bypass of Halligan Protected Mitigation Releases that are
released from Halligan New Reservoir Capacity past the North Poudre Canal diversion
structure to the Halligan Qualifying Stream Reach. This replacement/rebuild will create
a mechanism for keeping water in the North Fork at times when the North Poudre
Irrigation Company is diverting water into the North Poudre Canal.
E. Fort Collins is the owner of several water rights that have been decreed for storage in
Halligan New Reservoir Capacity, either directly or by operation of exchanges. These
rights, which are collectively referred to in this Agreement as the “Halligan Mitigation
2 The additional capacity created by the enlargement of Halligan Reservoir qualifies as “New Reservoir Capacity”
as defined in section 37-92-102(8)(b)(III), C.R.S.
EXHIBIT A TO RESOLUTION 2025-083
Page 3 of 12
Release Rights,” are described as follows:
i. Pursuant to the decree entered in Case No. 2013CW3185, Water Division 1, Fort
Collins is the owner of a water storage right for the enlarged Halligan Reservoir.
ii. Fort Collins is the owner of shares in several ditch companies that have decreed
water rights that divert from the Cache la Poudre River (the “Southside Ditches”).
Pursuant to the decrees entered in Case Nos. 1992CW129 and 2005CW323, Water
Division 1, these Southside Ditches shares have been changed to allow for storage
of water available to the shares in the enlarged Halligan Reservoir. The 92CW129
and 05CW323 decrees also include decreed appropriative rights of exchange that,
when operated, can provide for storage of water in the enlarged Halligan
Reservoir. The Southside Ditches shares are decreed as the sources of substitute
supply for these exchanges.
iii. Pursuant to the decree entered in Case No. 2014CW3158, Water Division 1, Fort
Collins is the owner of a water storage right for Rigden Reservoir. The 14CW3158
decree also includes decreed appropriative rights of exchange. Water released
from storage in Rigden Reservoir, including the 2014CW3158 water storage right
and other water sources that are decreed for storage in Rigden Reservoir, can be
used as the source of substitute supply to allow diversion of water by exchange
for storage in the enlarged Halligan Reservoir.
iv. Fort Collins is the owner of shares in the Water Supply and Storage Company
(“WSSC”). Pursuant to the decree entered in Case No. 2011CW265, Water Division
1, these WSSC shares have been changed to allow for storage of water available to
the shares in the enlarged Halligan Reservoir. The 2011CW265 decree also includes
decreed appropriative rights of exchange. Water available to the WSSC shares that
is released from storage at several decreed locations is used as the source of
substitute supply to allow diversion of water by exchange for storage in the
enlarged Halligan Reservoir.
v. Fort Collins has been in discussions with the Cache La Poudre Water Users
Association (“CLPWUA”) concerning the possibility of Fort Collins’ use of
CLPWUA’s 1/8 interest in the Grey Mountain Reservoir Right that was originally
decreed in Case No. 80CW355, Water Division 1. If an agreement is reached, Fort
Collins expects that water available under the 1/8 interest would be stored in the
enlarged Halligan Reservoir and could be a source for Protected Mitigation
Releases.
EXHIBIT A TO RESOLUTION 2025-083
Page 4 of 12
F. Fort Collins was required under Section 37-60-122.2, C.R.S., to submit a Fish and Wildlife
Mitigation and Enhancement Plan for the Halligan Project (“Halligan FWMEP”) and
obtain recommendations from the Colorado Parks and Wildlife Commission and the
Division of Parks and Wildlife (collectively “CPW”), and the CWCB concerning, and
adoption by the Governor of, the Halligan FWMEP as the official state position on
mitigation actions required for the Halligan Project.
G. The Halligan FWMEP was adopted by the CWCB as the official state position on
mitigation actions required for the Halligan Project’s impacts on fish and wildlife
resources at its regular meeting held July 19-20, 2023. A copy of the Halligan FWMEP is
attached to this Agreement as Exhibit A. The Halligan FWMEP describes Fort Collins’
commitments to making releases from Halligan New Reservoir Capacity for delivery to
and through a Qualifying Stream Reach located on the North Fork, and, in accordance
with Section 37-92-102(8), to attempt to protect those releases from diversion, exchange,
or use by holders of conditional or vested water rights or other persons that would cause
reductions to those releases at any location within the Halligan Qualifying Stream Reach
that would result in stream flows below the target rates identified in the Halligan FWMEP
and this Agreement. The Halligan FWMEP describes Fort Collins’ plan to make
mitigation releases from Halligan Reservoir under the Winter Release Plan and Summer
Low-Flow Program described in Recital I, below. The Halligan FWMEP also describes
making enhancement releases from the Temporary Environmental Pool (“TEP”) in the
enlarged Halligan Reservoir, as also described in Recital I. The CWCB and Fort Collins
intend in entering this Agreement that the mitigation and enhancement releases
described in the Halligan FWMEP and this Agreement (collectively the “Halligan
Mitigation Releases”) will be dedicated to the CWCB for use as Protected Mitigation
Releases within the Halligan Qualifying Stream Reach to avoid,minimize, and mitigate
impacts to water quality and the aquatic and riparian environments within the Halligan
Qualifying Stream Reach and to preserve and improve the natural environment to a
reasonable degree.
H. The Qualifying Stream Reach for the Halligan FWMEP and proposed Halligan Mitigation
Releases shall be an approximately 22-mile river reach on the North Fork extending
downstream from the replacement dam for the enlarged Halligan Reservoir to the
upstream end of Milton-Seaman Reservoir as described in this paragraph, below
(“Halligan Qualifying Stream Reach”). The approximate locations of the upstream and
downstream termination points of the Halligan Qualifying Stream Reach are as follows,
and are depicted on the map attached as Exhibit B:
i. Enlarged Halligan Reservoir Dam: The current approximate proposed location
for the replacement dam for the enlarged Halligan Reservoir is: NE1/4 SW1/4 of
EXHIBIT A TO RESOLUTION 2025-083
Page 5 of 12
Section 34, Township 11 North, Range 71 West, with the center point of the dam
being located on the North Fork at the following UTM coordinates: (Zone 13,
NAD83) 471510 N, 4525323 E.
ii. Milton-Seaman Reservoir: The proposed downstream termination point for the
Halligan Qualifying Stream Reach will be at the upper end of the operational
highwater line for Milton-Seaman Reservoir, described as: a point on the North
Fork located in the SW1/4 NE1/4 of Section 28, Township 9 North, Range 70 West,
at UTM coordinates (Zone 13, NAD83) 4507738 N, 480094 E.
I. Fort Collins wishes to dedicate to the CWCB, at no cost and for instream flow use in the
Halligan Qualifying Stream Reach as Protected Mitigation Releases, the Halligan
Mitigation Releases using the Halligan Mitigation Release Rights. At its regularly
scheduled public meeting held _________, the CWCB considered Fort Collins’ proposed
dedication of the Halligan Mitigation Releases to the CWCB in accordance with Sections
37-92-102(3) and (8), C.R.S., and Rules 6 and 11 of the Rules Concerning the Colorado
Instream Flow and Natural Lake Level Program, 2 C.C.R. 408-2, and determined that the
proposed Halligan Mitigation Releases would be best utilized as Protected Mitigation
Releases in the amounts described below in Table 2, for instream flow use to assist in
preserving and improving the water flows through the Halligan Qualifying Stream Reach
up to the winter, spring, and summer flow rates recommended by CPW described in
Table 1:
Table 1: CPW Recommended Flow Rates to preserve and improve the natural environment
Preserve ISF Target Rates Improve ISF Target Rates
Up to 12 cfs Between 12 and 13 cfs
Up to 30 cfs Between 30 and 53 cfs
Up to 30 cfs Between 30 and 53 cfs
The CWCB found that deliveries of the Halligan Mitigation Releases under this
Agreement as Protected Mitigation Releases are appropriate to preserve and improve the
natural environment to a reasonable degree within the Halligan Qualifying Stream Reach
at rates up to the identified flow rates found appropriate by the CWCB, and thus
authorized the CWCB Director to execute this Agreement.
Table 2: Halligan Mitigation Releases
Winter Release Plan (October 1 – April 30)Continuous release of Max.: 1,267 AF/year
Summer Low-Flow Program (May 1 – Sept. 30)Releases to maintain at least Max.: 1,517 AF/year
Temporary Environmental Pool Releases* Releases up to the improve ISF target 500-1,000 AF/year
EXHIBIT A TO RESOLUTION 2025-083
Page 6 of 12
*The TEP Releases can be made at any time of the year and will be used as additional
flows to preserve and improve the natural environment up to the “improve” flow rates
described in Table 1. Fort Collins dedicates the TEP releases to the CWCB up to the flow
rates and volumes described in Table 2. In addition, although not dedicated to the CWCB
by this Agreement as Halligan Mitigation Releases for potential Protected Mitigation
Releases, consistent with section 5.1.1.1 of the Halligan FWMEP, TEP releases may be
made at rates higher than the CWCB’s preserve and improve target rates shown in Table
1.
The Winter Release Plan, including its applicable terms and conditions, is described in
detail in section 4.2.1.1 of the Halligan FWMEP and includes the continuous release of a
minimum of 3 cfs from October 1 through April 30 from the enlarged Halligan Reservoir
to the North Fork and the Halligan Qualifying Stream Reach each year using water stored
in the Halligan New Reservoir Capacity.
The Summer Low-flow Plan, including its applicable terms and conditions, is described
in detail in section 4.2.1.2 of the Halligan FWMEP and includes adjustment of Halligan
Reservoir storage operations or release of water stored in the Halligan New Reservoir
Capacity to maintain a minimum target flow of 5 cfs from May 1 through September 30
in the Halligan Qualifying Stream Reach (as measured at three gaging stations along the
North Fork, as described in the Halligan FWMEP).
Fort Collins will also operate the TEP that is described in detail in section 5.1.1.1 of the
Halligan FWMEP, which includes the applicable terms and conditions. In accordance
with section 5.1.1.1, under this operation, during the period between completion of
construction of the enlarged Halligan Reservoir and the future date when Fort Collins
reaches the full water demand levels associated with storage of its water resources in the
Halligan New Reservoir Capacity, Fort Collins will dedicate and release on an annual
basis a variable volume of water to the North Fork to provide downstream environmental
benefits.
J. The CWCB and Fort Collins wish to cooperate as contemplated by Section 37-92-102(8),
C.R.S., to protect the Halligan Mitigation Releases identified in the Halligan FWMEP and
in this Agreement as Protected Mitigation Releases and to preserve and improve stream
flows in the Halligan Qualifying Stream Reach of the North Fork in a manner consistent
with the terms of the Halligan FWMEP and any decree obtained by Fort Collins and the
CWCB.
EXHIBIT A TO RESOLUTION 2025-083
Page 7 of 12
NOW, THEREFORE, the CWCB and Fort Collins agree as follows:
DEDICATION AND DELIVERY
1. Subject to the terms of this Agreement and the water court decree to be entered
adjudicating the Halligan Mitigation Releases as Protected Mitigation Releases that the
CWCB intends to acquire from Fort Collins pursuant to Section 37-92-102(8), C.R.S., Fort
Collins will release and deliver water stored in the Halligan New Reservoir Capacity
using its Halligan Mitigation Release Rights. Such releases will be done in the manner
and at the volumes, rates of flow, and times to be determined at the sole discretion of Fort
Collins to be necessary to satisfy the Halligan Mitigation Releases identified in the
Halligan FWMEP and this Agreement, for exclusive use by the CWCB as Protected
Mitigation Releases as authorized by Section 37-92-102(8), C.R.S.
2. No delivery of water is required when water from the Halligan Mitigation Release Rights
is not available for delivery.
3. As described in §§ 4.2.1.1, 4.2.1.2, 4.2.1.7, and 5.1.1.1 of the Halligan FWMEP, there may
be circumstances when the Halligan Mitigation Releases cannot be made to the full
amounts described in the Halligan FWMEP and this Agreement.
4. Once Fort Collins notifies the CWCB that the enlarged Halligan Reservoir is operational
and the Halligan Mitigation Releases are being made, pursuant to its decreed ability, the
CWCB shall protect the Halligan Mitigation Releases delivered to and through the
Halligan Qualifying Stream Reach as Protected Mitigation Releases from diversion or use
by exchange by other water users by, when necessary, requesting administration by the
Colorado State Engineer and the Division One Engineer to prevent diversion of or use by
exchange of the Halligan Mitigation Releases within the Halligan Qualifying Stream
Reach by other water users. If the CWCB does not or cannot protect the full amount of
the Halligan Mitigation Releases in accordance with the terms of this Agreement, nothing
in this Agreement shall prevent Fort Collins from exercising the Halligan Mitigation
Release Rights in accordance with their respective decrees but without protection by the
CWCB within the Halligan Qualifying Stream Reach.
CONDITIONS OF THE CWCB’S USE OF THE HALLIGAN MITIGATION RELEASES
5. Subject to water court approval pursuant to Section 37-92-102(8), C.R.S., the CWCB shall
use the Halligan Mitigation Releases in the amounts identified in Table 2, above, to help
maintain stream flows in the North Fork within the described Halligan Qualifying Stream
Reach to preserve and improve the natural environment to a reasonable degree in
EXHIBIT A TO RESOLUTION 2025-083
Page 8 of 12
amounts up to the target rates identified in Table 1, including releases from the TEP up
to the target rates that the CWCB determined are necessary to preserve or improve the
natural environment. Water made available for Protected Mitigation Releases under the
Halligan Mitigation Release Rights will be stored by Fort Collins in the Halligan New
Reservoir Capacity and released to the North Fork at the upstream point of the Halligan
Qualifying Stream Reach for instream flow use by the CWCB within that reach. Subject
to Paragraphs 2 and 3 above and the other terms of this Agreement, Halligan Mitigation
Releases to be Protected Mitigation Releases from the Halligan New Reservoir Capacity
under this Agreement to and through the Halligan Qualifying Stream Reach would be:
i. under the Winter Release Plan, continuous release of 3 cfs during October 1
through April 30; and
ii. under the Summer Low-flow Plan, releases to maintain at least 5 cfs (which may
include additional amounts to offset transit losses) during May 1 through
September 30; and
iii. under the TEP, releases up to the maximum CPW Recommended “improve” rates
identified in Table 1, which may occur at any time during the year.
The replacement dam for the enlarged Halligan Reservoir would be constructed to
deliver for decreed beneficial use the water used to make the Halligan Mitigation
Releases. In accordance with the Halligan FWMEP, Halligan Mitigation Releases will be
made to and through the Halligan Qualifying Stream Reach throughout the year at the
flow rates described in this Agreement and the Halligan FWMEP and subsequently
rediverted by Fort Collins in accordance with the decrees for the Halligan Mitigation
Release Rights, including the decree to be entered that approves the Halligan Mitigation
Releases as Protected Mitigation Releases.
6. Fort Collins’ delivery of water for the CWCB’s use for instream flows within the Halligan
Qualifying Stream Reach in accordance with this Agreement in no way provides the
CWCB an operating or ownership interest in any of Fort Collins’ Halligan Project
facilities, its other facilities, or any of its water rights, as they exist now or may exist in
the future.
7. The CWCB’s right to use the Halligan Mitigation Releases delivered to and through the
Halligan Qualifying Stream Reach under this Agreement extends to and terminates at the
downstream termination point of the Halligan Qualifying Stream Reach as described in
Recital H.
EXHIBIT A TO RESOLUTION 2025-083
Page 9 of 12
USE OF THE HALLIGAN MITIGATION RELEASES
DOWNSTREAM OF THE QUALIFYING STREAM REACH
8. In accordance with Sections 37-92-102(3) and (8), and Section 37-87-102(4), C.R.S., the
water court decree that Fort Collins and the CWCB intend to acquire pursuant to Section
37-92-102(8), C.R.S., that adjudicates the Halligan Mitigation Releases as Protected
Mitigation Releases, and the decrees for the Halligan Mitigation Release Rights, Fort
Collins intends to and shall redivert the Halligan Mitigation Releases at or downstream
of the downstream termination point of the Halligan Qualifying Stream Reach, either
directly at a Surface Point of Diversion or by using the Halligan Mitigation Releases as
the source of substitute supply for a decreed exchange, thus using the rediverted water
for the decreed beneficial uses.
WATER COURT PROCEEDINGS
9. As authorized by Sections 37-92-102(8)(d)(III) and (IV), C.R.S., the CWCB and Fort Collins
agree to act as co-applicants to file an application in water court seeking approval of the
Halligan Mitigation Releases as Protected Mitigation Releases and to cooperate in
obtaining a final water court decree approving the Halligan Mitigation Releases as
Protected Mitigation Releases.
i. Fort Collins has the burden of satisfying the required elements of the water court
application filed under Section 37-92-102(8), including, as necessary, proving no
injury and defending against any claim of injury to uses or exchanges of water
being made pursuant to appropriations or practices in existence on the date of the
filing of the application for the proposed protection of the Halligan Mitigation
Releases as Protected Mitigation Releases. However, in accordance with Section
37-92-102(8)(f)(I)(A), the CWCB has the burden of demonstrating to the water
court that it duly determined that the proposed protection of the Halligan
Mitigation Releases as Protected Mitigation Releases is appropriate as stream
flows to preserve or improve the natural environment to a reasonable degree
within the Halligan Qualifying Stream Reach.
ii. Except for its own attorney and court filing fees, the CWCB is not responsible for
paying costs of prosecuting the application, including the costs of hiring a
consulting engineer or other witnesses or any attorney fees of other parties.
RECORDS AND ACCOUNTING
10. Fort Collins shall be responsible for maintaining all records and accounting necessary for
EXHIBIT A TO RESOLUTION 2025-083
Page 10 of 12
the implementation of this Agreement, and all records required by the Division Engineer
and applicable water court decrees for administration of the Halligan Mitigation Releases
as Protected Mitigation Releases, using forms mutually agreeable to Fort Collins and the
CWCB.
11. Fort Collins will provide accounting related to the operation of this Agreement to the
CWCB upon reasonable request.
MISCELLANEOUS PROVISIONS
12. The term of this Agreement is perpetual unless terminated under the provisions of this
paragraph. Except as expressly provided herein, this Agreement may only be amended
or terminated by the written agreement of the parties in a subsequent agreement or
amendment executed with the same formality as this Agreement. If Fort Collins decides,
in its sole discretion, to no longer pursue the enlargement of Halligan Reservoir, Fort
Collins may terminate this Agreement by providing notice pursuant to Paragraph 21. In
such event, the Halligan FWMEP will not be implemented. If, at such time, a water court
action for approval of Protected Mitigation Releases for the Halligan Project is pending
in water court, then the CWCB and Fort Collins agree to withdraw such water court
application. Fort Collins will be responsible for any costs owed to objectors because of
the withdrawal. If a decree authorizing Protected Mitigation Releases for the Halligan
Project has already been entered, Fort Collins will take appropriate actions to cancel that
decree.
13. The CWCB is not responsible for modification of any structures that may be necessary
for use of the Halligan Mitigation Releases to preserve or improve the natural
environment.
14. This Agreement shall not be assignable by either party without the written consent of the
other party.
15. Pursuant to Section 37-92-102(3), C.R.S., the terms of this Agreement shall be enforceable
by each party as a water matter in the District Court for Water Division No. 1; provided,
however, that before commencing any action for enforcement of this Agreement, the
party alleging the violation shall notify the other party in writing of the alleged violation
and the parties shall make a good faith effort to resolve their differences through informal
consultation.
16. Specific performance of this Agreement shall be the sole and exclusive remedy for failure
of either party to comply with any provision of this Agreement.
EXHIBIT A TO RESOLUTION 2025-083
Page 11 of 12
17. Enforcement of this Agreement and all the rights and obligations described herein is
reserved solely to the CWCB and Fort Collins and not to any other person or entity. Any
services or benefits which other persons or entities may receive because of this
Agreement are incidental to the Agreement and do not create any third-party rights for
these other persons or entities.
18. This Agreement shall be construed in accordance with the laws of the State of Colorado
and shall be interpreted broadly to achieve its purposes. To the extent than any one or
more of the identified Halligan Mitigation Release Rights or the Halligan Mitigation
Releases operations described in this Agreement are not authorized for use as Protected
Mitigation Releases in a decree entered by the water court pursuant to the application
filed by Fort Collins and the CWCB in accordance with Section 37-92-102(8), this
Agreement shall continue in full force and effect with respect to those Halligan Mitigation
Release Rights and Halligan Mitigation Releases operations that are decreed as Protected
Mitigation Releases.
19. Nothing in this Agreement shall preclude or limit Fort Collins from making releases or
deliveries of water yielded by the Halligan Mitigation Release Rights for any purposes
allowed by law.
20. Notwithstanding any other provisions of this Agreement to the contrary, the obligations
of Fort Collins and CWCB in fiscal years after the fiscal year of this Agreement shall be
subject to appropriation of funds sufficient and intended therefor, with each party having
the sole discretion to determine whether the subject funds are sufficient and intended for
use under this Agreement.
21. Any notice or request required or allowed to be given under this Agreement shall be in
writing and considered effective when delivered by email or certified or registered mail
addressed to the parties as follows:
If to the CWCB: Colorado Water Conservation Board
Stream and Lake Protection Section
1313 Sherman Street, Room 721
Denver, Colorado 80203
DNR_CWCBISF@state.co.us
If to Fort Collins: City of Fort Collins
c/o Nicole Poncelet-Johnson, Director of Water Utilities, and
Jen Dial, Water Resources Manager
EXHIBIT A TO RESOLUTION 2025-083
Page 12 of 12
P.O. Box 580
Fort Collins, Colorado 80522
Nponcelet-johnson@fcgov.com; jdial@fcgov.com
IN WITNESS WHEREOF, the CWCB and Fort Collins have executed this Agreement as
of the last date of execution set forth below.
COLORADO WATER CONSERVATION BOARD
By: ________________________________________
Date: _________________________
CITY OF FORT COLLINS
By: ________________________________________
Kelly DiMartino, City Manager
Date: _________________________
ATTEST:
By: ______________________________________
City Clerk
APPROVED AS TO LEGAL FORM:
By: ______________________________________
Eric Potyondy, Senior Assistant City Attorney
EXHIBIT A TO RESOLUTION 2025-083
Halligan Water Supply Project
FINAL
Fish and Wildlife
Mitigation and Enhancement Plan
Prepared by
with support from
June 7, 2023
EXHIBIT A TO RESOLUTION 2025-083
Contents
Acronyms and Abbreviations .................................................................................................................. v
Key Terminology ................................................................................................................................... vii
Executive Summary ........................................................................................................................... ES-1
1 Introduction ............................................................................................................................ 1-1
1.1 Purpose of this Fish and Wildlife Mitigation and Enhancement Plan ............................ 1-1
1.2 Contents of this Fish and Wildlife Mitigation and Enhancement Plan ........................... 1-2
1.3 Halligan Project Overview ............................................................................................ 1-2
1.3.1 Operations, Storage, and Water Rights ........................................................... 1-7
1.3.2 Estimated Halligan Project Cost....................................................................... 1-9
1.4 Regulatory Framework ................................................................................................ 1-9
1.4.1 National Environmental Policy Act .................................................................. 1-9
1.4.2 Clean Water Act Section 404 ......................................................................... 1-10
1.4.3 Federal Wildlife Regulations .......................................................................... 1-11
1.4.4 State of Colorado .......................................................................................... 1-12
1.4.5 Larimer County ............................................................................................. 1-12
1.4.6 Consultation, Coordination, and Public Input ................................................ 1-13
2 Fort Collins Water Portfolio ..................................................................................................... 2-1
2.1 Existing Water Supply and Demand ............................................................................. 2-1
2.2 Water Conservation and Water Restrictions ................................................................ 2-3
2.3 Future Water Demand ................................................................................................. 2-3
2.4 Related Regional Activities .......................................................................................... 2-4
2.4.1 Shared Vision Planning .................................................................................... 2-4
2.4.2 Fort Collins’ River Efforts ................................................................................. 2-4
2.4.3 Northern Integrated Supply Project ................................................................ 2-5
2.4.4 Poudre Runs Through It .................................................................................. 2-5
2.4.5 Poudre Flows Plan........................................................................................... 2-5
2.4.6 Wildfire Recovery and Monitoring Efforts ....................................................... 2-6
2.4.7 Coalition for the Poudre River Watershed ....................................................... 2-6
2.4.8 Preble’s Meadow Jumping Mouse Site Conservation Team ............................. 2-7
2.4.9 Platte River Species ......................................................................................... 2-7
3 Fish and Wildlife Conditions and Impacts ................................................................................ 3-1
3.1 Basis of Halligan Project Effects ................................................................................... 3-1
3.2 Resources Evaluated.................................................................................................... 3-2
3.3 Surface Water Hydrology ............................................................................................. 3-2
3.3.1 Current Conditions for Surface Water Hydrology ............................................ 3-3
3.3.2 Halligan Project Effects on Surface Water Hydrology ....................................... 3-3
3.4 Surface Water Quality ................................................................................................. 3-6
3.4.1 Current Conditions for Surface Water Quality ................................................. 3-6
EXHIBIT A TO RESOLUTION 2025-083
3.4.2 Halligan Project Effects on Surface Water Quality ........................................... 3-6
3.5 Aquatic Resources ..................................................................................................... 3-11
3.5.1 Current Conditions for Aquatic Resources ..................................................... 3-11
3.5.2 Halligan Project Effects on Aquatic Resources ............................................... 3-13
3.5.3 Wetlands ...................................................................................................... 3-15
3.6 Terrestrial Wildlife Including Big Game ...................................................................... 3-15
3.6.1 Current Conditions for Big Game ................................................................... 3-16
3.6.2 Current Conditions for Other Wildlife............................................................ 3-16
3.6.3 Halligan Project Effects on Big Game and Other Wildlife ............................... 3-16
3.7 Rocky Mountain Bighorn Sheep ................................................................................. 3-19
3.7.1 Current Conditions for Bighorn Sheep ........................................................... 3-19
3.7.2 Lone Pine Herd Additional Data Evaluation ................................................... 3-19
3.7.3 Lone Pine Herd Management Challenges ...................................................... 3-21
3.7.4 Halligan Project Effects on Rocky Mountain Bighorn Sheep ........................... 3-22
3.8 Special-status Species ................................................................................................ 3-23
3.8.1 Current Conditions for Federally Listed Species ............................................. 3-24
3.8.2 Current Conditions for State-listed Species ................................................... 3-25
3.8.3 Halligan Project Effects on Federally Listed Species ....................................... 3-28
3.8.4 Halligan Project Effects on State-listed Species.............................................. 3-29
3.9 Recreation ................................................................................................................. 3-31
3.9.1 Current Conditions ........................................................................................ 3-31
3.9.2 Halligan Project Effects on Recreation and Public Access ............................... 3-33
3.9.3 Evaluation of Future Public Use of the Enlarged Halligan Reservoir ............... 3-34
4 Proposed Fish and Wildlife Mitigation Plan............................................................................. 4-1
4.1 Mitigation Approach.................................................................................................... 4-1
4.1.1 Regulatory Mitigation Categories .................................................................... 4-2
4.1.2 Changes from DEIS Conceptual Mitigation Plan ............................................... 4-2
4.2 Avoidance and Minimization ....................................................................................... 4-4
4.2.1 Flow-related Operational Measures ................................................................ 4-4
4.2.2 Infrastructure Design Measures .................................................................... 4-19
4.2.3 Construction-related Measures ..................................................................... 4-20
4.2.4 Overhead Power Line and Pole Relocation .................................................... 4-31
4.2.5 Halligan Reservoir Sediment Management Plan ............................................ 4-31
4.3 Compensatory Mitigation Measures .......................................................................... 4-32
4.3.1 Preservation as Early Compensatory Mitigation Measure.............................. 4-32
4.3.2 Fish Passage at the Fort Collins Intake at Gateway Park................................. 4-35
4.3.3 Compensatory Mitigation for Halligan Project Impacts on Bighorn Sheep ..... 4-35
4.3.4 Compensatory Mitigation for Halligan Project Impacts on Stream
Temperature ................................................................................................. 4-36
4.3.5 Compensatory Mitigation for Halligan Project Impacts on Wetlands ............. 4-36
4.3.6 Special-status Species ................................................................................... 4-36
EXHIBIT A TO RESOLUTION 2025-083
4.3.7 Recreational Resources ................................................................................. 4-37
4.3.8 Instream Water Rights .................................................................................. 4-39
4.4 Mitigation Costs and Schedule ................................................................................... 4-39
5 Proposed Fish and Wildlife Enhancement Plan ....................................................................... 5-1
5.1 Enhancement Measures .............................................................................................. 5-1
5.1.1 Aquatic Resources Enhancements ................................................................... 5-1
5.2 Surface Water Quality Enhancement ........................................................................... 5-5
5.2.1 Sediment-related Operational Measures......................................................... 5-5
5.2.2 Passive Aeration in Outlet Structure ................................................................ 5-5
5.2.3 Terrestrial Resources Enhancements............................................................... 5-6
5.3 Fort Collins Ecological Resource Monitoring ................................................................ 5-6
5.3.1 Streamflow Monitoring ................................................................................... 5-6
5.3.2 Sediment, Macroinvertebrates, and Water Quality Monitoring ....................... 5-7
5.3.3 Bighorn Sheep Collaring Study ........................................................................ 5-7
5.4 Enhancement Costs and Schedule ............................................................................... 5-7
6 References .............................................................................................................................. 6-1
Appendixes
Appendix A Mapbook
Appendix B Summary of Mitigation Measures
Appendix C Surface Water Quality Supplemental Information
Appendix D Water Quality Sampling Location Maps
Appendix E Parks and Wildlife Commissioner and Public Comment Summary
Appendix F FWMEP Virtual Open House Public Comments
Tables
Table 1-1. Estimated Halligan Project Costs Shown in 2022 Dollars ....................................................... 1-9
Table 3-1. Summary of Halligan Project Effects on Riffle and Pool Complexes ..................................... 3-15
Table 3-2. Cumulative, Permanent, and Temporary Impacts of Halligan Project on Big Game
Habitat................................................................................................................................... 3-18
Table 3-3. Summary of DEIS Impact Evaluation of Halligan Project on Species of Concern ................... 3-23
Table 3-4. 2021 Bat Survey Results ..................................................................................................... 3-26
Table 4-1. Ramping Rate Limitations for Decreasing Releases from Fort Collins’ Portion of an
Enlarged Halligan Reservoir[a] ................................................................................................. 4-12
Table B-1. FWMEP Measures and Costs ................................................................................................ B-1
Table C-2. Median and 85th Percentiles of Total Iron and Dissolved Iron Data ...................................... C-9
Figures
Figure 1-1. Overview of Halligan Project Elements and Other Infrastructure ......................................... 1-4
Figure 1-2. Overview of the Halligan Existing and Enlarged Surface Areas ............................................. 1-5
Figure 1-3. Proposed Halligan Dam Footprint and Construction Areas .................................................. 1-6
Figure 2-1. Fort Collins Utilities Water Supply System ........................................................................... 2-2
EXHIBIT A TO RESOLUTION 2025-083
Figure 3-1. Average Monthly Residence Times With and Without the Halligan Project Based on
Common Technical Platform Flows, 1980–2005 ....................................................................... 3-8
Figure 3-2. Average Monthly Percentage of Flow from the North Fork on the Main Stem below the
North Fork Confluence[a] ........................................................................................................ 3-11
Figure 3-3. Halligan Project Elements and Bighorn Sheep Suitable Habitat .......................................... 3-20
Figure 3-4. Sections 29 and 32 on the Western Edge of Halligan Reservoir .......................................... 3-32
Figure 4-1. North Fork, Zero-Flow in Phantom Canyon, May 2002 ........................................................ 4-6
Figure 4-2. North Fork, Zero-Flow Conditions below Calloway Diversion, August 2018 .......................... 4-9
Figure 4-3. Foraging Elk Herd .............................................................................................................. 4-20
Figure 4-4. Ute Ladies’-tresses Orchid ................................................................................................. 4-21
Figure 4-5. Townsend’s Big-Eared Bat ................................................................................................. 4-21
Figure 4-6. Raptor Nesting Platform in Laporte, Colorado ................................................................... 4-22
Figure 4-7. Proposed Construction Schedule to Avoid and Minimize Bighorn Sheep Disturbance at
North Poudre Canal and Calloway Diversions ......................................................................... 4-28
Figure 4-8. Land Ownership and Mitigation Areas around Halligan Reservoir ...................................... 4-34
Figure 4-9. Fort Collins Intake at Gateway Park ................................................................................... 4-35
Figure 5-1. North Poudre Canal Diversion Structure .............................................................................. 5-3
Figure 5-2. Calloway Diversion Structure .............................................................................................. 5-4
Figure C-1. Bathymetric Map of Halligan Reservoir (Based on 2003 Survey) at Existing Full Pool ........... C-2
Figure C-2. Average Monthly Residence Time in Halligan Reservoir (Based on Observed Release Rates
and Storage Volumes from 2010 to 2018) ................................................................................ C-2
Figure C-3. Dissolved Oxygen Profiles in Halligan Reservoir (2021) ........................................................ C-3
Figure C-4. Observed Chlorophyll a Concentrations in Halligan Reservoir (2016 to 2019) ...................... C-3
Figure C-5. Example Dissolved Oxygen Profiles from Seaman Reservoir, 2019 ....................................... C-4
Figure C-6. Example Profile Pair from Halligan Reservoir Showing Temperature Exceedance and No
Adequate Refuge; July 10, 2018 ............................................................................................... C-5
Figure C-7. Hardness across the North Fork, 2016-2019 ........................................................................ C-6
Figure C-8. Example of Thermal Shock below Halligan Dam (NBH), 2017 ............................................... C-7
Figure C-9. Observed Weekly Average Temperatures across the North Fork on a Typical Summer
Day with Bottom Releases from Halligan Reservoir, 7/19/2019 ................................................ C-8
Figure C-10. Observed Daily Maximum Temperatures across the North Fork on a Typical Summer
Day with Bottom Releases from Halligan Reservoir, 7/19/2019 ................................................ C-8
Figure C-11. Weekly Average Temperatures on Select Summer Days in 2018 across the Main Stem
Focus Reach ........................................................................................................................... C-11
Figure C-12. Daily Maxima on Select Summer Days in 2018 across the Main Stem Focus Reach .......... C-11
Figure C-13. Average Monthly Percentage of Flow from the North Fork on the Main Stem below
the North Fork Confluence (based on observed flows 2009–2018) ......................................... C-13
Figure C-14. Diagram of Geologic Zones of the Poudre River Main Stem Focus Reach ......................... C-14
Figure C-15. Poudre River Fraction of Flow by Source, 2016 Monthly Averages................................... D-15
Figure D-1. Water-Quality Sampling Locations on the North Fork below Halligan Reservoir and its
Tributaries ............................................................................................................................... D-1
Figure D-2. Macroinvertebrate and Pebble Count Sampling Sites on the North Fork ............................. D-2
Figure D-3. Water Quality Sampling Locations along the Poudre River .................................................. D-3
Figure D-4. Temperature Gages along the North Fork and Poudre River ............................................... D-4
EXHIBIT A TO RESOLUTION 2025-083
Acronyms and Abbreviations
Term Definition
2008 Mitigation Rule 2008 U.S. Army Corps of Engineers, Compensatory Mitigation for Losses
of Aquatic Resources; Final Rule
bighorn sheep Rocky Mountain bighorn sheep
BLM U.S. Department of the Interior Bureau of Land Management
BMP best management practice
C-BT Colorado–Big Thompson, in reference to the C-BT Project
CCR Code of Colorado Regulations
CDNR Colorado Department of Natural Resources
CDPHE Colorado Department of Public Health and Environment
CFR Code of Federal Regulations
cfs cubic feet per second
CMP Conceptual Mitigation Plan
Coalition Coalition for the Poudre River Watershed
Commission Parks and Wildlife Commission
Corps U.S. Army Corps of Engineers
CPW Colorado Parks and Wildlife
CRS Colorado Revised Statute
CWA Clean Water Act
CWCB Colorado Water Conservation Board
DAU data analysis unit
DEIS Draft Environmental Impact Statement
DM daily maximum
DO dissolved oxygen
DWR Colorado Department of Water Resources
EIS Environmental Impact Statement
EPA U.S. Environmental Protection Agency
ESA Endangered Species Act
FEIS Final Environmental Impact Statement
Fort Collins City of Fort Collins, acting through its Fort Collins Utilities
FR Federal Register
FWMEP Fish and Wildlife Mitigation and Enhancement Plan
GIS geographic information system
GMU Game Management Unit
GPS global positioning system
Halligan Project, Project Halligan Water Supply Project
LAPCR Landowners Association for Phantom Canyon Ranches
Main Stem Main Stem of the Cache la Poudre River
MLOW multilevel outlet works
EXHIBIT A TO RESOLUTION 2025-083
Term Definition
MMI macroinvertebrate multimetric index
NEPA National Environmental Policy Act
NISP Northern Integrated Supply Project
North Fork North Fork of the Cache la Poudre River
Northern Water Northern Colorado Water Conservancy District
ROD Record of Decision
SAM species activity mapping
TMDL total maximum daily load
U.S.C. United States Code
USFWS United States Fish and Wildlife Service
WQCD Water Quality Control Division
EXHIBIT A TO RESOLUTION 2025-083
Key Terminology
Key terminology used throughout this report is defined in this section and is listed in alphabetic order. If
a citation is listed, the definition provided is directly from that regulatory reference.
Best Management Practices. Best management practices (BMPs) refer to structural and non-structural
methods, measures, or practices implemented to prevent, reduce, or mitigate adverse impacts resulting
from construction and operation of a project. BMPs may also be called control measures.
Poudre River-related Terminology:
Exchange Reach. For purposes of this Fish and Wildlife Mitigation and Enhancement Plan (FWMEP),
the Exchange Reach is defined as the segment of the Main Stem between its confluence with the
North Fork and the Fort Collins Intake(s): the Fort Collins Intake and Munroe Gravity Canal are
located approximately 0.6 river mile and 1.5 river miles upstream of the North Fork confluence,
respectively. Exchanges are a unique type of water right. They are, in essence, a trade where water
is diverted at upstream locations when an equal amount of water is delivered to or released at
downstream locations.
Main Stem. In this FWMEP, the Main Stem refers to the portion of the Poudre River from the
Munroe Diversion to the confluence with the South Platte River.
Cooperating Agency. In the Draft Environmental Impact Statement (EIS) (Section 1.2), the United States
(U.S.) Army Corps of Engineers (Corps) refers to cooperating agencies pursuant to 40 Code of Federal
Regulations (CFR) Section 1501.8. The regulation states: “Upon request of the lead agency, any other
Federal agency with jurisdiction by law shall be a cooperating agency. In addition, any other Federal
agency which has special expertise with respect to any environmental issue may be a cooperating
agency. A State, Tribal or local agency of similar qualifications may become a cooperating agency by
agreement with the lead agency.”
Ecological Function. Ecological function is defined as the work performed or role played individually or
collectively by the physical, chemical, and biological processes that contribute to the maintenance of the
aquatic and terrestrial environments that constitute the natural environment (Law Insider n.d.).
Enhancement-related Terminology:
Enhancement. Colorado Parks and Wildlife’s (CPW’s) rules and regulations for fish and wildlife
mitigation and enhancement plans pursuant to Colorado Revised Statute (CRS) 37-60-122.2 define
enhancement as “the improvement of the total value of fish and wildlife resources affected by the
project beyond that required by mitigation and beyond that which would occur without the project”
(2 Code of Colorado Regulations [CCR] 406-16). This involves activities conducted within existing
aquatic or other resources that heighten, intensify, or improve one or more functions of the
resource. Enhancement is often implemented for a specific purpose, such as to improve water
quality, flood water retention, or wildlife habitat.
Enhancement Plan. CPW’s rules and regulations for fish and wildlife mitigation and enhancement
plans pursuant to CRS 37-60-122.2 define an enhancement plan as a “document describing the
measures to be completed by the applicant which will enhance fish and wildlife resources beyond
that which would occur without the project. It includes a cost estimate for the implementation of
the plan and a schedule for completion” (2 CCR 406-16). Fort Collins’ enhancement plan is set forth
in Chapter 5 of this FWMEP.
EXHIBIT A TO RESOLUTION 2025-083
Environmental Effect/Impacts. An environmental effect or impact is defined as any change to the
environment, whether adverse or beneficial, resulting from an action taken.
Direct effects/impacts are those that would result directly from implementing the Halligan Water
Supply Project (Halligan Project). Most direct effects would occur from construction and from
inundation by the enlarged Halligan Reservoir.
Indirect effects/impacts are those that result from the Halligan Project but occur later in time or are
farther removed in distance. The primary indirect effects would be associated with Project-related
flow changes in the North Fork and the Main Stem.
Flow-Related Operational Measures. These are measures that would re-establish a perennial flow
regime of 3 cubic feet per second (cfs) to 5 cfs or more to the North Fork below the enlarged Halligan
Reservoir, minimize abrupt changes to flows that would otherwise result from Fort Collins’ operations,
and allow for a portion of the hydrologic peak flows to bypass the enlarged reservoir when Fort Collins
could otherwise be diverting water to storage. These measures include the Winter Release Plan,
Summer Low-flow Plan, Ramping Rate Limitations, and Peak Flow Bypass Program.
Fort Collins. The proponent of the Halligan Project is the City of Fort Collins, acting through Fort Collins
Utilities.
Fort Collins Intake(s). Two diversions are located on the Main Stem where Fort Collins diverts water
for municipal purposes. The two diversions that deliver water to Fort Collins’ Water Treatment
Facility are:
Fort Collins Intake. Diversion on the Main Stem located approximately 0.6 river mile upstream of
the North Fork confluence, which diverts water into the Fort Collins pipeline.
Munroe Canal. Diversion on the Main Stem located approximately 1.5 river miles upstream of the
North Fork confluence, which delivers Fort Collins’ water into the Pleasant Valley Pipeline.
In the future, releases from Fort Collins’ portion of the enlarged Halligan Reservoir will most likely be
diverted by exchange at the Fort Collins Intakes. Of the approximately 1,700 acre-feet of annual average
releases by Fort Collins under the Halligan Project, about 90 percent are diverted at the Fort Collins
Intake and about 10 percent are diverted at Munroe Canal.
Inherent Benefits. These are beneficial effects on natural resources as a result of the Halligan Project,
including but not limited to ecological benefits resulting from flow-related operational measures and the
natural re-establishment of wetland and riparian communities at the enlarged reservoir shoreline and
on the North Fork.
Linkage Area. Is being used to describe habitat that successfully moves animals across fracture zone.
Fracture zones are highways, railroads, and similar potential barriers to wildlife movement and the
adjacent development of private lands. So, even though use may vary by season of year or not it is still
used as a movement or linkage area connecting two blocks of viable, suitable, and used habitat
(Interagency Grizzly Bear Committee Public Lands Wildlife Linkage Task Force 2004).
Mitigation-related Terminology:
Mitigation. CPW’s rules and regulations for fish and wildlife mitigation and enhancement plans
under CRS 37-60-122.2 define mitigation as “any action or measures taken to address undesirable
project impacts on fish and wildlife resources which may be accomplished in several ways, including
reducing, minimizing, rectifying, compensating, or avoiding impacts” (2 CCR 406-16). As used in this
FWMEP, mitigation includes:
EXHIBIT A TO RESOLUTION 2025-083
Avoidance. These are measures undertaken to avoid adverse impacts of a project, such as
design refinements to reduce the project footprint (U.S. Environmental Protection Agency [EPA]
1990).
Minimization. This consists of measures undertaken to minimize adverse impacts through
project modifications and permit conditions (40 CFR Sections 230.70–77).
Compensatory Mitigation. This means any action or measures taken to address unavoidable
project impacts on fish and wildlife resources after all appropriate and practical avoidance and
minimization measures have been implemented. This may be accomplished in several ways,
including rectifying or compensating impacts.
Early Mitigation. These are mitigation efforts initiated by Fort Collins before construction and
operation of the Halligan Project, or in some cases before developing this FWMEP.
Mitigation Plan. CPW’s rules and regulations for fish and wildlife mitigation and enhancement plans
developed pursuant to CRS 37-60-122.2 define a mitigation plan as a “document describing the
measures to be completed by the applicant which will mitigate losses to fish and wildlife resources
resulting from the project. It includes a cost estimate for the implementation of the plan and a time
schedule for completion.” (2 CCR 406-16). Fort Collins’ mitigation plan is set forth in Chapter 4 of
this FWMEP.
Preservation. This involves permanently protecting ecologically important aquatic or other
resources by implementing appropriate legal and physical mechanisms, such as conservation
easements and title transfers. Preservation of aquatic resources may include protecting upland
areas adjacent to aquatic resources as necessary to ensure protection or enhancement of the
aquatic ecosystem (2008 Mitigation Rule [USACE 2008]; 73 Federal Register [FR] 19593).
Restoration. This is defined as reestablishing or rehabilitating an aquatic or other resource with the
goal of returning natural or historical functions and characteristics to a former or degraded
resource. Restoration may result in a gain in resource function, acres, or both (2008 Mitigation Rule;
73 FR 19593).
Monitoring-Related Terminology:
Baseline Assessments. This consists of assessments undertaken before project implementation to
document existing conditions in order to understand how resources may be affected by the project
or are the subject of mitigation measures before mitigation and/or enhancement actions are taken.
Construction Compliance Monitoring. This consists of monitoring undertaken to evaluate whether
construction-related avoidance and minimization measures are being implemented.
Mitigation Compliance Monitoring. This involves monitoring undertaken to evaluate whether
compliance with the compensatory mitigation requirements are being met.
Voluntary Enhancement Monitoring. This consists of monitoring that Fort Collins would perform
voluntarily and that does not directly relate to monitoring required to evaluate compliance.
Project. The Halligan Water Supply Project is also referred to as the “Halligan Project” in this FWMEP,
which primarily entails the enlargement of Halligan Reservoir, construction of the replacement Halligan
Dam, and replacement of the North Poudre Canal Diversion. The Project is referred to as Fort Collin’s
“Proposed Action” in the National Environmental Policy Act (NEPA) process and associated EIS.
Halligan Project Area. This term is used to describe the general area of Project construction and the
area affected by operations of the enlarged Halligan Reservoir. The Halligan Project Area refers generally
EXHIBIT A TO RESOLUTION 2025-083
to the area of the enlarged Halligan Reservoir; the North Poudre Canal Diversion; the North Fork
downstream of Halligan Reservoir to the confluence with the Main Stem; the Exchange Reach; and areas
temporarily or permanently affected by construction activities, plus a 0.5-mile buffer for noise, visual, or
vibratory disturbance. The Halligan Project Area also includes roads that would be temporarily widened
to provide access for construction of the Halligan Project. The Halligan Project Area does not include
mitigation sites that are not adjacent to the areas listed in this section (refer to Section 1.3).
EXHIBIT A TO RESOLUTION 2025-083
Executive Summary
The City of Fort Collins, acting through Fort Collins Utilities (Fort Collins), is pursuing the Halligan Water
Supply Project (Halligan Project or Project), a municipal water supply project. Implementation of the
Halligan Project requires various regulatory approvals, including federal permitting processes
administered by the United States (U.S.) Army Corps of Engineers (Corps) under the Clean Water Act
(CWA) and the National Environmental Policy Act (NEPA). A Draft Environmental Impact Statement
(DEIS) was issued by the Corps for the Halligan Project on November 22, 2019 and serves as the basis for
documenting current conditions and impacts. Fort Collins has prepared this Fish and Wildlife Mitigation
and Enhancement Plan (FWMEP) in coordination with Colorado Parks and Wildlife (CPW) staff pursuant
to Colorado Revised Statute (CRS) 37-60-122.2 and applicable rules and regulations (2 CCR] 406-16).
The Halligan Project Overview. The Halligan Project primarily involves enlarging the existing Halligan
Reservoir on the North Fork of the Cache la Poudre River (North Fork), located approximately 25 miles
northwest of Fort Collins. The existing Halligan Reservoir currently supplies water to shareholders of the
North Poudre Irrigation Company (NPIC), which would continue to use and operate the historical
reservoir pool. Fort Collins would store its water in the enlarged portion of the reservoir. Fort Collins’
water would primarily come from water rights historically used to irrigate now-developed lands in the
Fort Collins area that have been transferred to municipal use. Existing infrastructure would be used to
deliver water from the enlarged reservoir pool to Fort Collins’ water treatment facility.
Since the release of the DEIS in November 2019, Fort Collins has modified their Proposed Action from
rehabilitation and raising of the existing dam to constructing a new dam, which is also referred to as the
replacement dam. Halligan Reservoir would be enlarged by replacing the existing 114-year-old dam, as
of 2023, with a new dam constructed approximately 200 feet downstream of the existing dam. The
replacement dam would raise the existing reservoir elevation by approximately 25 feet, to increase the
total water storage capacity by approximately 8,200 acre-feet, for a total enlarged reservoir volume of
approximately 14,600 acre-feet. Enlarging the reservoir would increase the current surface area of
Halligan Reservoir from 253 to 391 acres.
Fort Collins would release its water from the enlarged reservoir into the North Fork below the dam.
Fort Collins’ releases would be conveyed approximately 24 miles in the North Fork to its confluence with
the Main Stem of the Cache la Poudre River (Main Stem). Using an exchange, Fort Collins would then
divert a like amount of water at either of the two Fort Collins Intakes on the Main Stem, located
approximately 0.6 river mile and 1.5 river miles upstream.
The Halligan Project also includes rebuilding the existing North Poudre Canal Diversion located on the
North Fork approximately 6 river miles downstream of Halligan Reservoir. The replacement ensures that
Fort Collins’ releases from the enlarged Halligan Reservoir would bypass the diversion and remain in the
North Fork.
In the DEIS Section 1.4.2, the Corps defined Fort Collins’ purpose and need for the Halligan Project as “to
provide additional system firm yield for Fort Collins in order to satisfy an additional need of
approximately 7,900 acre-feet per year to meet its projected approximate 2,065 municipal and
industrial demands with water of a quality comparable to the water now delivered to its customers.” In
addition, the Halligan Project ensures that Fort Collins can satisfy future water supply and demands by
providing a storage reserve for emergency water supply, increasing drought security, and improving
water system reliability and flexibility.
The Fish and Wildlife Mitigation and Enhancement Plan. This FWMEP was developed in collaboration
with CPW staff pursuant to CRS 37-60-122.2 and applicable regulations (2 CCR 406-16). In addition to
EXHIBIT A TO RESOLUTION 2025-083
describing the Halligan Project and its context, this FWMEP includes both a mitigation plan (Chapter 4)
and an enhancement plan (Chapter 5).
Fort Collins understands that CPW staff’s interpretation of these regulations are that only a portion of
Fort Collins’ mitigation and enhancement measures will be considered to be part of the Parks and
Wildlife Commission’s (Commission’s) proposed mitigation recommendation for purposes of CRS
Section 37-60-122.2 and 2 CCR 406-16. Fort Collins also understands that CPW staff’s interpretation is
that the Commission acknowledges the importance and value of all mitigation and enhancement
measures as described in Fort Collins’ Modified Proposed Action and required by other agencies, but
distinguishes a different category of which the Commission is recommending on top of, or in addition to
those measures proposed within the Modified Proposed Action and required by other agencies.
Fort Collins desires to complete this process for the FWMEP and has thus not taken a position on CPW
staff’s interpretation.
This FWMEP thus includes a comprehensive description of all of Fort Collins’ planned mitigation and
enhancement measures for the Halligan Project that are related to fish and wildlife. Some of these
commitments and measures are included as part of Fort Collins’ Modified Proposed Action for its federal
permitting requirements in the Final EIS, and some of these commitments and measures were
developed for purposes of this FWMEP. As such, Fort Collins’ total estimated mitigation and
enhancement costs for all measures, as well as CPW’s interpretation of what are attributable to the
Commission’s recommendations pursuant to CRS Section 37-60-122.2 are presented as part of this
FWMEP. All cost commitments presented in the FWMEP are depicted in 2022 dollars and will be
increased in the amount of the U.S. Bureau of Labor Statistics Consumer Price Index for Denver-Aurora-
Lakewood from January 1, 2023 to the date of final payment under the FWMEP obligation.
Chapters 1 and 2. These sections provide an overview and summary of the Halligan Project and its
context. Chapter 1 includes information regarding current operations at Halligan Reservoir and along the
North Fork, as well as proposed future operations after the reservoir is enlarged. Chapter 1 also provides
current estimated costs and an overview of the regulatory framework. Chapter 2 describes Fort Collins’
water portfolio and extensive water conservation efforts. Additional and more detailed technical
information and analyses are provided in the Corps’ DEIS and its technical reports (Corps 2019).
Chapter 3. This section summarizes fish and wildlife conditions in the Halligan Project Area and effects
of the Halligan Project. Since completion of Halligan Reservoir in 1909, operations of Halligan Dam and
the North Poudre Canal Diversion have significantly and adversely affected river flows in the North Fork
and impaired downstream aquatic habitats.
The Halligan Project effects described in this FWMEP are based on detailed evaluations in the DEIS and
supporting technical reports, and further analyses conducted since the DEIS. Most Halligan Project
permanent impacts would occur from inundation by the enlarged reservoir along a portion of the North
Fork upstream of the reservoir, including a Colorado Water Conservation Board (CWCB) instream flow
water right, and at the footprint of the replacement dam. Temporary impacts would occur from
construction activities, including access and materials mobilization and stockpiling, at the replacement
dam and at the North Poudre Canal Diversion. Minor indirect impacts are anticipated for the North Fork
between Halligan Reservoir. As well as minor indirect impacts for the Mainstem in the form of reduced
runoff flows while diverting water to storage in the enlarged reservoir and for the Main Stem in the form
of reduced flows within the Exchange Reach when Halligan Releases are being diverted by exchange into
the Fort Collins Intakes. This FWMEP also addresses additional concerns regarding the Halligan Project
that were identified by CPW staff during Project consultations.
EXHIBIT A TO RESOLUTION 2025-083
Chapter 4. The mitigation plan describes the measures that would be used to avoid and minimize
Project impacts on fish and wildlife resources, as well as measures that would be used to compensate
for unavoidable impacts on fish and wildlife resources. Key measures include:
•Flow-related operational measures, including the following:
–Winter Release Plan to provide continuous releases of 3 cubic feet per second (cfs) from the
enlarged reservoir to the North Fork from October 1 through April 30 each year
–Summer Low-Flow Program to maintain a continuous flow of at least 5 cfs in the approximately
22 miles of the North Fork between Halligan Dam and Seaman Reservoir from May 1 to
September 30 each year
–Ramping rate limitations on Fort Collins’ operations to gradually change flow rates associated
with diversions and releases from the enlarged reservoir
–Peak Flow Bypass Program to maintain historical peak flushing flows for at least 3 days
•Operational measures for sediment management, such as construction-related sediment controls
and the Peak Flow Bypass Program
•Infrastructure design measures, including the following:
–Design of new replacement Halligan Dam with redundancy in operation function
–Enlarged outlet conduit to allow for the peak flow bypass
–Design of the partial or total demolition of the existing Halligan Dam and features that remain in
place, the details of which are not known at this time
•Construction-related measures, including the following:
–Best management measures, including control of erosion, dust, stormwater, and waste
–Preconstruction surveys for certain federal- and state-listed species, including noxious weeds
–Provide raptor nesting/roosting platforms
–Modified existing infrastructure design for North Poudre Canal Diversion
–Construction timing restrictions at the North Poudre Canal and Calloway Diversions
•Compensatory mitigation for unavoidable Halligan Project impacts on fisheries, water quality and
temperature, terrestrial wildlife, federally and state-listed species, and inundated instream flow
water rights.
–Early mitigation measure consisting of a conservation easement on the 4,557-acre Roberts
Ranch
–Design and construction of features to improve fish passage around the Fort Collins Intake on
the Main Stem
–Bighorn sheep mitigation, including improved food and water access, movement monitoring,
avoiding/minimizing construction impacts, and compensation for mortalities
–Funding for stream restoration as mitigation for stream temperature impacts
Chapter 5. The enhancement plan summarizes the measures that Fort Collins proposes to incorporate
into the Halligan Project that are not required to meet regulatory mitigation needs, but rather would be
implemented to improve existing conditions for fish and wildlife resources in and around the Halligan
Project Area. Key enhancement measures are summarized in this section.
EXHIBIT A TO RESOLUTION 2025-083
•Aquatic resource enhancements including the following:
–Create a temporary environmental pool within Halligan Reservoir
–Provide fish passage around the North Poudre Canal Diversion
–Improve the North Fork channel at the Calloway Diversion and remove some or all elements of
the diversion structure to support flow, sediment transport, and fish movement
–Implement potential future ramping rate limitations for NPIC’s use of the enlarged reservoir
•Terrestrial resource enhancements include the following:
–Restrict domestic sheep and goat grazing on Fort Collins-owned land or on any easements on
lands around Halligan Reservoir during construction
–Advocate cessation of domestic sheep and goat grazing on other lands
•Recreation resource enhancements include the following:
–Reconcile title chain confusion related to certain lands thought to be part of the Cherokee State
Wildlife Area – Middle Unit, with Fort Collins acquiring such lands and conveying an easement to
CPW across these lands for public use
–Fund a public access lease with Roberts Ranch
–Establish parking area outside of the enlarged reservoir inundation area for public access
EXHIBIT A TO RESOLUTION 2025-083
1 Introduction
The City of Fort Collins (Fort Collins) proposes the Halligan Project to meet its strategic objective of
providing a reliable, high-quality water supply. The Halligan Project is a municipal water supply project
designed to provide additional system firm yield for Fort Collins to satisfy its projected municipal and
industrial water demands with water quality comparable to that of the water now delivered to its
customers.
The Halligan Project primarily involves enlargement of the existing Halligan Reservoir and replacement
of the existing North Poudre Canal Diversion. Halligan Reservoir would be enlarged by replacing the
existing 114-year-old dam, as of 2023, with a new dam constructed approximately 200 feet downstream
of the existing dam. The Halligan Project is described in greater detail in the Draft Environmental Impact
Statement (DEIS) Halligan Water Supply Project (United States [U.S.] Army Corps of Engineers
[Corps] 2019) and is referred to as Fort Collins’ “Proposed Action,” with certain aspects relevant to fish
and wildlife discussed in this Fish and Wildlife Mitigation and Enhancement Plan (FWMEP).
1.1 Purpose of this Fish and Wildlife Mitigation and
Enhancement Plan
This FWMEP was developed pursuant to Colorado Revised Statute (CRS) 37-60-122.2 and applicable
rules and regulations (2 Code of Colorado Regulations [CCR] 406-16). This FWMEP sets forth the actions
that Fort Collins would take to mitigate the potential impacts that the Halligan Project may have on fish
and wildlife resources, and to enhance existing conditions in the Halligan Project Area (the general area
of Project construction and the area affected by operations of the enlarged Halligan Reservoir; refer to
the definition in the Key Terminology section and also refer to Figure 1-1). In addition to addressing
Halligan Project impacts, which are based on the DEIS and subsequent analyses, this FWMEP also
addresses additional concerns regarding the Halligan Project that were identified by Colorado Parks and
Wildlife (CPW) staff during Project consultations.
Fort Collins understands that CPW staff’s interpretation is that the Parks and Wildlife Commission
(Commission) acknowledges the importance and value of all mitigation and enhancement measures as
described in Fort Collins’ Modified Proposed Action and required by other agencies but distinguishes a
different category of which the Commission is recommending on top of, or in addition to, those
measures proposed within the Modified Proposed Action and required by other agencies. Therefore, the
Commission’s proposed mitigation recommendation for purposes of CRS 37-60-122.2 and 2 CCR 406-16
may be a subset of Fort Collins’ mitigation and enhancement measures described in this FWMEP.
It is Fort Collins’ understanding that all measures in this FWMEP have been evaluated by CPW staff to
determine what would be recommended by the Commission. Rather than parsing the distinctions
throughout the FWMEP, the categories based on CPW staff’s interpretation are captured in Appendix B,
which shows a distinction between Fort Collins’ total estimated mitigation and enhancement costs and
those CPW’s staff believe are attributable to the Commission’s recommendations via separate cost
columns.
Fort Collins intends to complete the mitigation and enhancement measures developed as part of this
FWMEP, as well as those identified in Clean Water Act (CWA) Section 401 water quality certification and
the Corps CWA Section 404 permit and associated Record of Decision (ROD). It is anticipated that
compliance with the mitigation plan portion of this FWMEP will be attached as permit conditions by the
Corps on the ROD and CWA Section 404 permit, and the mitigation commitments in this FWMEP will be
in addition to any other measures required by other entities.
EXHIBIT A TO RESOLUTION 2025-083
1.2 Contents of this Fish and Wildlife Mitigation and Enhancement
Plan
This FWMEP includes both a mitigation plan and an enhancement plan. The following sections are
included in this FWMEP:
• Chapter 1–Introduction (this chapter) describes the Halligan Project, purpose of the FWMEP,
current operations of Halligan Reservoir, and proposed operations of an enlarged Halligan Reservoir,
water rights, estimated Project cost, and the regulatory framework for the Halligan Project.
• Chapter 2–Fort Collins Water Portfolio summarizes Fort Collins’ existing and future water supply
and demand, as well as demand management through water conservation. Chapter 2 also provides
information about current and related regional activities.
• Chapter 3–Fish and Wildlife Conditions and Impacts describes current conditions and summarizes
the anticipated effects of the Halligan Project on fish and wildlife resources, including inherent
benefits of the Halligan Project.
• Chapter 4–Proposed Fish and Wildlife Mitigation Plan describes the measures that would be used
to avoid and minimize impacts on fish and wildlife resources, as well as those measures that would
be used to compensate for unavoidable impacts on fish and wildlife resources.
• Chapter 5–Proposed Fish and Wildlife Enhancement Plan summarizes the measures that
Fort Collins proposes to voluntarily incorporate into the Halligan Project that exceed the mitigation
requirements and are proposed to improve existing conditions in and around the Halligan Project
Area.
• Chapter 6–References provides detailed references to the works cited in this FWMEP.
Maps of key Project elements and water quality sampling stations are provided in Appendix A and
Appendix D. Appendix B provides a tabular summary of the components of this FWMEP. Appendix C is a
table that lists the mitigation and enhancement measures described in Sections 4 and 5, including the
cost of each item. Appendix E is a memorandum responding to Commissioner and public comments.
Appendix F provides copies of all written public comments received on the FWMEP.
1.3 Halligan Project Overview
The Halligan Project includes enlarging the existing Halligan Reservoir on the North Fork, located
approximately 25 miles northwest of Fort Collins in Larimer County. The location of the Halligan Project
is shown on Figure 1-1. Appendix A provides overview and detailed maps of key Project elements.
Halligan Reservoir would be enlarged by replacing the existing 114-year-old dam, as of 2023, with a new
dam constructed approximately 200 feet downstream of the existing dam. The replacement dam would
raise the existing reservoir elevation by approximately 25 feet to increase the total water storage
capacity by approximately 8,200 acre-feet, for a total enlarged reservoir volume of approximately
14,600 acre-feet. Enlarging the reservoir would increase the current surface area of Halligan Reservoir
from 253 to 391 acres. Figure 1-2 shows the reservoir inundation area at the current and proposed
enlarged ordinary high water mark, and Figure 1-3 presents anticipated construction features, including
the replacement dam infrastructure, access roads, and potential borrow or stockpile areas.
The Halligan Project also includes rebuilding the existing North Poudre Canal Diversion located
approximately 6 river miles downstream of Halligan Reservoir to allow Fort Collins’ releases from the
enlarged Halligan Reservoir to bypass the diversion and remain in the North Fork.
EXHIBIT A TO RESOLUTION 2025-083
The Halligan Project ensures that Fort Collins can satisfy future water supply and demands by:
•Meeting future water demands of the Fort Collins Utilities water service area
•Providing a storage reserve for emergency water supply
•Increasing drought security
•Improving water system reliability and flexibility
EXHIBIT A TO RESOLUTION 2025-083
Figure 1-1. Overview of Halligan Project Elements and Other Infrastructure
(Refer to Appendix A for detailed maps)
EXHIBIT A TO RESOLUTION 2025-083
Figure 1-2. Overview of the Halligan Existing and Enlarged Surface Areas
EXHIBIT A TO RESOLUTION 2025-083
Figure 1-3. Proposed Halligan Dam Footprint and Construction Areas
EXHIBIT A TO RESOLUTION 2025-083
1.3.1 Operations, Storage, and Water Rights
1.3.1.1 Current Operations of Halligan Reservoir
Halligan Reservoir is an existing on-stream reservoir that North Poudre Irrigation Company (NPIC)
constructed in 1909 to supply water to its shareholders. Fort Collins acquired Halligan Reservoir and
certain surrounding lands from NPIC in 2004 pursuant to a 1993 option agreement. Although Fort Collins
owns Halligan Reservoir, the reservoir is currently operated by NPIC and supplies water to NPIC
shareholders only. Water is currently released from Halligan Reservoir and diverted at the North Poudre
Canal Diversion, where it is conveyed in the North Poudre Canal into NPIC’s ditch and reservoir system
for delivery to NPIC shareholders. The 1993 option agreement between Fort Collins and NPIC allows
Fort Collins to enlarge Halligan Reservoir but requires Fort Collins to reconvey the reservoir and
associated lands back to NPIC if Fort Collins abandons the Halligan Project or is otherwise unable to
enlarge the reservoir.
Under current operations, NPIC fills Halligan Reservoir starting in the fall. Filling continues until water
levels reach the dam spillway crest and water spills over the dam into the North Fork. Spilling typically
occurs annually in the spring but can occur as early as December or January. NPIC begins releasing water
to the North Fork from the dam outlet in the spring. NPIC then diverts the releases at the North Poudre
Canal Diversion, which is located approximately 6 river miles downstream of Halligan Dam.
During the irrigation season (summer through early fall), NPIC typically “sweeps” the river by diverting
all flows into North Poudre Canal, the initial portion of which is a tunnel through the canyon wall. Where
the tunnel daylights approximately 1.9 miles downstream, water that NPIC is not entitled to use or that
is in excess of the North Poudre Canal’s capacity is returned to the river through a return structure.
These operations typically result in low-flow conditions, dry-up points, and disconnected pools in the
1.9-mile stretch of the North Fork between the North Poudre Canal Diversion and where some water is
returned (Figure 1-1).
NPIC frequently releases water from Halligan Reservoir at a rate that they can divert into the North
Poudre Canal at the North Poudre Canal Diversion. During the irrigation season, NPIC typically diverts all
water released from Halligan Reservoir, unless spilling at the dam results in a larger amount of water
than can be diverted at the North Poudre Canal.
At the end of the irrigation season, NPIC typically commences diverting water into Halligan Reservoir for
storage and releases from Halligan Reservoir cease. Winter reservoir operations typically result in low-
flow conditions, dry-up points between November and March, and disconnected pools in the North Fork
for approximately 10 miles between Halligan Reservoir and the first downstream tributary, Rabbit Creek
(Figure 1-1).
Dam inspection reports summarize current conditions of the dam, as indicated by the State of
Colorado’s Dam Safety Office. Inspection reports indicate that the existing Halligan Reservoir dam is
currently sound. However, the dam is over 114-years old, as of 2023, and seepage through the dam and
freeze-thaw cycles will continue to degrade the dam and present an increasing safety risk unless it is
rehabilitated. As described in the DEIS, significant construction would be required in the future to
rehabilitate the existing dam if the Halligan Project is not implemented. Design of the replacement
Halligan Dam is underway and involves close coordination with the State of Colorado’s Dam Safety
Office.
1.3.1.2 Proposed Future Operations of the Enlarged Halligan Reservoir
The enlarged Halligan Reservoir would be operated by Fort Collins. Although Fort Collins intends to meet
any operational commitments included in this FWMEP, actual operations of the Halligan Project may
EXHIBIT A TO RESOLUTION 2025-083
change pursuant to applicable permits and approvals, water rights administration, or other things
beyond Fort Collins’ control. No changes to these commitments are anticipated at this time. If
operations of the Halligan Project change significantly from those described in this FWMEP, Fort Collins
and CPW will re-evaluate whether additional mitigation measures are necessary as a result.
The enlarged reservoir would continue to be filled with direct flows from the North Fork. Fort Collins
would generally keep its portion of the enlarged Halligan Reservoir relatively full until the water is
needed to meet demands during droughts or other water supply shortages.
Fort Collins’ future operations of the enlarged Halligan Reservoir have been designed to not only avoid
and minimize potential impacts from the Halligan Project, but also improve the existing conditions of the
North Fork below Halligan Reservoir. Fort Collins’ operations of the enlarged Halligan Reservoir include
year-round releases from the enlarged reservoir to provide flows in the North Fork below Halligan
Reservoir and eliminate dry-up points that are currently found along the North Fork at various times of
the year. These flow-related operational measures are described in detail in Section 4.2.1.
Fort Collins’ releases from the enlarged Halligan Reservoir would be delivered down the North Fork to its
confluence with the Main Stem and typically “exchanged up” to the Fort Collins Intake(s) on the Main
Stem. NPIC would continue to operate its portion of the enlarged Halligan Reservoir, including
diversions, storage, and releases, as it does currently.
Fort Collins would generally use water from Halligan Reservoir to meet demands after other sources of
water are unavailable. The enlarged Halligan Reservoir has no predetermined demand or release
pattern, but in general, releases from the enlarged Halligan Reservoir would occur as follows:
•To meet Fort Collins’ reusable water demand when other reusable water sources are lacking
•During dry periods or other water supply disruptions as needed to meet Fort Collins single-use and
reusable water demands when other Fort Collins’ water sources are unavailable or insufficient
1.3.1.3 Water Rights for Storage in an Enlarged Halligan Reservoir
Fort Collins would use several water rights to fill the enlarged Halligan Reservoir, including the following:
•Changed water rights attributable to shares in the so-called “Southside Ditches” companies (Arthur
Irrigation Company, Larimer County Canal No. 2 Irrigating Company, and New Mercer Ditch
Company)
•The Halligan Reservoir Enlargement conditional water right
•A portion of the one-eighth interest of the Grey Mountain conditional water right
•Changed water rights attributable to shares in the Water Supply and Storage Company
The majority of Fort Collins’ water stored in the enlarged Halligan Reservoir would come from the
changed water rights in the “Southside Ditches” companies that were historically used to irrigate farms
in portions of the Fort Collins area that have since been developed. Fort Collins changed the use of these
water rights and, pursuant to the Water Court decrees approving the changes, Fort Collins must
maintain the return flow patterns associated with the historical irrigation use of these water rights.
Thus, the Halligan Project is, for the most part, not a new demand on the Poudre River system as a
whole1, but instead, a conversion of water use from direct flow irrigation to municipal storage.
1The project will result in flow changes on the North Fork of the Poudre River, but not the overall Poudre system.
EXHIBIT A TO RESOLUTION 2025-083
1.3.2 Estimated Halligan Project Cost
Fort Collins’ Modified Proposed Action would cost an estimated $157.8 million2 (2022 dollars). The
estimated cost includes pre-construction costs (for example, field exploration and design), construction
costs (labor, equipment, materials, and supplies), and land and other acquisition costs. The project cost
estimate does not include costs of mitigation or enhancements (as described in Appendix B), or any
costs related to risk or uncertainty given the limited conceptual design that exists. Table 1-1 provides a
breakdown of the estimated project cost.
Table 1-1. Estimated Halligan Project Costs Shown in 2022 Dollars
Task Estimated cost
Pre-construction[a] $13,865,000
Construction[a] $130,719,000
Permitting & Legal $2,892,000
Land Acquisition $10,315,000
Total $157,791,000
[a] The sum of these two values are presented in Appendix B.
1.4 Regulatory Framework
The Halligan Project has undergone and continues to undergo significant regulatory scrutiny at the
federal, state, and local levels. For final Halligan Project authorization, Fort Collins is required to obtain
numerous federal and state permits, licenses, and approvals as identified in DEIS Section 1.6
(Corps 2019). The following subsections summarize the primary regulatory processes related to the
Halligan Project effects on fish and wildlife, although other approvals and processes may be required
that are not included in this summary.
1.4.1 National Environmental Policy Act
The National Environmental Policy Act (NEPA) requires federal agencies to consider the potential
environmental impacts of proposed actions before authorizing a “major federal action.” The Halligan
Project is considered a “major federal action” because it may significantly affect the human
environment as defined by NEPA. The Halligan Project would discharge fill material into jurisdictional
waters of the U.S. and, thus, also require authorization by the Corps under CWA Section 404, as
described in Section 1.4.2. The Corps Omaha District, Denver Regulatory Office, is the lead federal
agency for the NEPA process and is preparing an Environmental Impact Statement (EIS) to evaluate
potential environmental impacts resulting from the Halligan Project. The Corps will use the EIS in
determining a final permit decision that will be documented in the ROD.
The Corps published a DEIS on November 22, 2019 (Corps 2019) that described analyses of the potential
environmental impacts associated with the Halligan Project. The analyses and DEIS were developed in
compliance with the Council on Environmental Quality’s NEPA regulations (40 Code of Federal
Regulations [CFR] Parts 1500–1508) and the Corps NEPA implementation procedures for its regulatory
program (33 CFR Part 325). The DEIS provides a comparison of the Halligan Project (described there as
2 These values are estimated by the Corps as part of the Halligan Project and done in a similar manner for all Halligan Project alternatives. They do not
reflect all the actual costs to Fort Collins of the Modified Proposed Action. For example, the Corps calculates Permitting & Legal expenses as 2% of Pre-
construction and Construction costs combined when actual expenses have been significantly more to date for Fort Collins.
EXHIBIT A TO RESOLUTION 2025-083
the Proposed Action) and several alternatives to the Halligan Project. The DEIS also addresses factors
relevant to the CWA Section 404(b)(1) guidelines (40 CFR Part 230) and applicable public interest review
criteria identified in 33 CFR Part 320.4. The Corps is currently developing a Final EIS (FEIS) that will
address comments on the DEIS received from the public, resource agencies, and other stakeholders.
The DEIS presents a draft Conceptual Mitigation Plan (CMP) prepared by Fort Collins (City of
Fort Collins 2019c) that includes both mitigation and enhancement measures. Based on public
comments received on the DEIS, comments from Project stakeholders, and discussions with CPW staff,
this FWMEP builds upon and/or replaces many of the aquatic life and terrestrial wildlife components of
the draft CMP. An updated final CMP will be prepared by Fort Collins for the Final EIS.
The U.S. Department of the Interior Bureau of Land Management (BLM) is a cooperating federal agency,
and will determine NEPA adequacy for Project activities or impacts that may occur on BLM lands.
1.4.2 Clean Water Act Section 404
CWA Section 404 regulates the discharge of dredged or fill material into waters of the U.S., including
jurisdictional wetlands. The CWA Section 404 permit program is administered by the Corps with
oversight by the U.S. Environmental Protection Agency (EPA) (EPA 1972). The Halligan Project would
result in a regulated discharge; therefore, Fort Collins is seeking authorization of the discharge under a
CWA Section 404 individual permit.
Projects subject to the CWA Section 404 individual permit process must comply with CWA
Section 404(b)(1) guidelines, which provide direction for evaluating activities regulated under CWA
Section 404. Under the guidelines, “no discharge of dredged or fill material may be permitted if there is
a practicable alternative to the proposed discharge which would have less adverse impact on the aquatic
ecosystem, so long as the alternative does not have other significant adverse environmental
consequences.” To comply with the guidelines, a permit applicant must take all appropriate and
practicable steps to avoid and minimize adverse impacts on waters of the U.S. Compensatory mitigation
may be required to offset any unavoidable impacts and ensure compliance with the CWA Section
404(b)(1) guidelines.
• CWA Section 401 Water Quality Certification— A CWA Section 401 water quality certification is a
state approval process for water quality impacts that is administered by the Water Quality Control
Division of the Colorado Department of Public Health and Environment (CDPHE) to implement CWA
Section 401 (refer to CRS 25-8-302(1)(f)). The CWA Section 401 water quality certification process is
conducted according to Regulation 82 (5 CCR Section 1002-82). Any additional mitigation conditions
or requirements that are required for CWA Section 401 water quality certification will be
incorporated into the CWA Section 404 permit. Fort Collins is collecting data and conducting
additional water quality and temperature analysis for the Halligan Project in preparation for the
CWA Section 401 water quality certification application.
1.4.2.1 2008 Compensatory Mitigation for Losses of Aquatic Resources
The Corps Colorado Mitigation Procedures (Corps 2020) describes compensatory mitigation procedures
for wetland and stream impacts in Colorado, and outlines the steps that the Corps districts may follow
to meet regulatory obligations. Although Colorado Mitigation Procedures was formally approved by the
Corps for mitigation procedures in April 2020, it has not been used on the Halligan Project because
mitigation planning was already well underway when these procedures were approved. The
compensatory mitigation plan will be consistent with Corps regulations and mitigation policy.
EXHIBIT A TO RESOLUTION 2025-083
The Corps and EPA established the type and extent of compensatory mitigation necessary to
demonstrate compliance with the CWA Section 404(b)(1) guidelines (40 CFR Part 230) in the
2008 Mitigation Rule (73 Federal Register [FR] 19593; EPA and Corps 2008).
The Corps determines the appropriate form and amount of compensatory mitigation required for a
Section 404 permit based on the nature and extent of anticipated unavoidable impacts on aquatic
resources. Fort Collins will prepare a wetlands mitigation plan independent of this FWMEP for future
authorization by the Corps as part of the CWA Section 404 permitting process.
1.4.3 Federal Wildlife Regulations
The following federal wildlife regulations apply to the Halligan Project:
•Endangered Species Act (ESA)—The ESA protects species that are federally listed as threatened or
endangered under the federal ESA of 1973 as amended (16 United States Code [U.S.C.] Section 1531
et seq.) (USFWS 1973). In accordance with ESA Section 7, projects with a federal nexus that could
affect federally listed species and/or their habitats require consultation with the U.S. Fish and
Wildlife Service (USFWS). Impacts on candidate species are not required to undergo a Section 7
consultation unless the species becomes listed during project planning and construction. In
accordance with ESA Section 7, the EIS describes evaluations conducted to determine potential
impacts on federally listed species from activities related to implementing the Halligan Project and
each alternative to the Halligan Project. A Biological Assessment is then conducted for the Project to
identify measures that compensate for the Project’s impacts on federally listed species and/or their
designated critical habitat. The USFWS then renders a Biological Opinion after they have reviewed
the Biological Assessment and consulted with the lead federal agency. The Corps has begun the
Section 7 consultation process for the Halligan Project.
•Migratory Bird Treaty Act and Bald and Golden Eagle Protection Act—The Migratory Bird Treaty
Act (16 U.S.C. Sections 703–712) established a federal prohibition, “unless permitted by regulations,
to pursue; hunt; take; capture; kill; attempt to take, capture, or kill; possess; offer for sale; sell; offer
to purchase; purchase; deliver for shipment; ship; cause to be shipped; deliver for transportation;
transport; cause to be transported; carry or cause to be carried by any means whatever; receive for
shipment; transportation, or carriage; or export at any time, or in any manner, any migratory bird,
part, nest, or egg of any such bird” (USFWS 2004). Similarly, the Bald and Golden Eagle Protection
Act (16 U.S.C. Sections 668–668c) prohibits the “taking” of bald or golden eagles, including their
parts, nests, and eggs. In accordance with the Acts and as part of the NEPA process, potential
impacts on protected bird species have been evaluated, and appropriate avoidance, minimization,
or mitigation measures have been incorporated into this FWMEP.
•Fish and Wildlife Coordination Act—The federal Fish and Wildlife Coordination Act
(16 U.S.C. Sections 661–666c) (USFWS 1934) places requirements on water development projects,
including consultation with the USFWS and state fish and wildlife agencies (in this case, CPW) when
the “waters of any stream or other body of water are proposed or authorized, permitted or licensed
to be impounded, diverted or otherwise controlled or modified” by any agency under a federal
permit or license. The consultation goal is conserving wildlife resources by preventing loss and/or
damage to them, as well as potentially improving the resources as part of the proposed project.
State-listed species are also considered during such a consultation. In Colorado, this requirement is
largely fulfilled through consultation with USFWS and CPW, and by developing and implementing
this FWMEP. The Corps must prepare a Fish and Wildlife Coordination Act report for the USFWS that
“provides 1) clear documentation of the proposed project’s impacts on fish and wildlife resources
EXHIBIT A TO RESOLUTION 2025-083
and 2) specific recommendations as to the measures that should be taken to conserve those
resources.”
1.4.4 State of Colorado
The following state statutes apply to various resources covered in this FWMEP and are most relevant to
the FWMEP:
•Fish and Wildlife Mitigation Plan—This FWMEP was prepared to satisfy the requirements of
CRS 37-60-122.2. The statute states that “fish and wildlife resources found in and around state
waters which are affected by the construction, operation, or maintenance of water diversion,
delivery, or storage facilities” are a “matter of statewide concern and that impacts on such
resources should be mitigated by the project applicants in a reasonable manner.” The statute
further explains that the extent and nature of the mitigation should be “economically reasonable
and maintain[s] a balance between the development of the state’s water resources and the
protection of the state’s fish and wildlife resources.”
Such fish and wildlife mitigation plans are to be developed by the project applicant, generally
working in cooperation with CPW staff members, and submitted to the Commission. If the
Commission and applicant agree on the plan, the Commission then forwards it to the Colorado
Water Conservation Board (CWCB) for adoption as the official state position on the mitigation
actions required of the applicant.
CRS 37-60-122.2 distinguishes mitigation of Halligan Project impacts from enhancement of fish and
wildlife resources over existing conditions. The Procedural Rules for the Commission (Chapter 16)
provide definitions for both a mitigation plan and an enhancement plan (refer to the Key
Terminology section of this report). This FWMEP includes both a mitigation plan that contains
measures developed to mitigate Halligan Project impacts, and an enhancement plan that enhances
fish and wildlife resources over and above existing levels without the Halligan Project. Fort Collins is
required by CRS 37-60-122.2 to submit a proposed mitigation plan, but submittal of an
enhancement plan is voluntary.
•CWCB Rule 7 Process—The enlarged Halligan Reservoir would inundate approximately 0.75 mile of
the North Fork upstream of the current reservoir where the CWCB holds a decreed instream flow
water right. Fort Collins would, therefore, need to undergo a process to seek approval to inundate
an instream flow under the CWCB’s instream flow program rules (Rule 7, 2 CCR 408-2) (CWCB n.d.).
During this process, the CWCB may seek recommendations from, among others, CPW and the
Colorado Division of Water Resources (DWR). CWCB would consider factors such as the extent of
inundation proposed, impacts on the natural environment, any unique or rare characteristics of the
instream flow water right to be inundated, any regulatory requirements or conditions imposed upon
the applicant by federal, state and/or local governments, land ownership, economic benefits, and
the mitigation or compensation offered by Fort Collins to offset adverse impacts on the instream
flow right. Ultimately, the CWCB Board would either approve, conditionally approve, defer, or deny
the request to inundate.
1.4.5 Larimer County
Colorado House Bill 74-1041 authorized certain local governments, including counties, to identify,
designate, and regulate areas and activities of state interest through a local permitting process to
provide them with control over certain development projects. The Halligan Project is located entirely
within Larimer County, and Larimer County is a cooperating agency on the Halligan Project. Larimer
County’s 1041 regulations are specified in the County’s land use code. Unless specifically exempted,
EXHIBIT A TO RESOLUTION 2025-083
Section 10.3.1(J) requires a 1041 Permit for “Site selection and construction of a new water storage
reservoir or expansion of an existing water storage reservoir resulting in a surface area at high water line
in excess of 50 acres, natural or manmade, used for the storage, regulation and/or control of water for
application to a beneficial use, including augmentation, commercial, domestic, industrial, municipal, and
replacement uses, provided this designation excludes water storage reservoirs used exclusively for
irrigation or stormwater detention facilities. A new water storage reservoir shall also include all
appurtenant uses, structures and facilities (i.e., those necessary and integral to the proper functioning of
the project), including internal roads, parks, parking, trails, recreational uses, and other uses.” The
Halligan Project thus requires a 1041 Permit from Larimer County pursuant to the procedures in Larimer
County’s land use code.
1.4.6 Consultation, Coordination, and Public Input
Fort Collins consulted with CPW during preparation of this plan. In addition, CPW and cooperating
agencies reviewed and commented on the DEIS and some associated reports. CRS 37-60-122.2 requires
CPW and the CWCB to review and provide input on the mitigation proposed to address Halligan Project
impacts on fish and wildlife resources. Although CRS 37-60-122.2 does not require public review and
input, Fort Collins and CPW have developed a process to also allow for public participation as part of the
development of this FWMEP.
The Corps (through the NEPA process), Fort Collins, and CPW have provided, and will continue to
provide, the following public meetings and opportunities to solicit input on the potential impacts and
mitigation for the Halligan Project:
• Fort Collins has provided many updates about the Halligan Project in public forums to Fort Collins
City Council and the Fort Collins Water Commission (previously known as the Water Board)
throughout the life of the Halligan Project. Fort Collins has also published newspaper articles about
the Halligan Project and maintains a website where the public can receive Halligan Project-related
updates and submit comments on the Halligan Project at any point. Fort Collins regularly seeks out
opportunities to educate and solicit feedback about the Halligan Project, including targeted
stakeholder presentations or discussions, distribution of information at community events, videos,
and social media posts.
• On January 26, 2006, the Corps submitted written requests to the EPA, USFWS, U.S. Forest Service,
CPW, Weld County, and Larimer County to participate as cooperating agencies in the preparation of
the then-planned joint EIS for the Halligan and Seaman Water Supply projects pursuant to 40 CFR
Section 1501.6. The Corps subsequently recognized that the CDPHE, Colorado Department of
Natural Resources (CDNR), Colorado State Historic Preservation Officer, and the BLM had expertise
or regulatory authority over aspects of the Halligan and Seaman Water Supply projects. Those
agencies were also invited and agreed to serve as cooperating agencies; the CPW, CDPHE, CDNR,
BLM, EPA, USFWS, and Larimer County accepted the invitation to serve as cooperating agencies, but
Weld County declined to serve as a cooperating agency. As of the writing of this FWMEP, the
proposal for the Seaman Water Supply Project has been withdrawn and is inactive.
• On February 1, 2006, the Corps published the Notice of Intent in the FR to prepare an EIS to analyze
the potential impacts of two water supply projects known as the Halligan-Seaman Water
Management projects in Northern Colorado (71 FR 5250).
• On February 23, 27, and 28, 2006, three public scoping meetings were held at the Livermore
Community Church in Livermore, the Lincoln Center in Fort Collins, and the Bunk House at Island
Grove in Greeley, respectively.
EXHIBIT A TO RESOLUTION 2025-083
•As part of the NEPA process, the Corps initially contacted 59 Native American tribes in writing to
solicit input regarding the Halligan Project. Only two tribes, the Standing Rock Sioux Tribe and the
Cheyenne River Sioux Tribe, responded to the request. On May 23, 2019, the Corps provided a
consultation letter to seven Native American tribes, including the Apache Tribe of Oklahoma, Gros
Ventre and Assiniboine Nations, Northern Cheyenne Tribe, Comanche Nation, Cheyenne-Arapaho
Tribes of Oklahoma, Arapaho Tribe of the Wind River Reservation, and the Northern Apache Tribe.
In meetings with Fort Collins, the Corps indicated that they will continue to reach out to tribal
contacts as the NEPA process continues.
•On November 22, 2019, the Corps published the DEIS for the Halligan Project. A public hearing was
held in Fort Collins on January 13, 2019, which was attended by approximately 85 people.
Comments on the DEIS were accepted through January 21, 2020. Approximately 60 written
comment letters or oral comments were received on the Halligan Project.
•On April 27, 2023, Fort Collins released the FWMEP Application on the Halligan Project website.
•From May 1 through May 15, 2023, Fort Collins hosted a virtual open house and comment period for
the public to review the FWMEP and provide feedback on the FWMEP.
–Fort Collins received eight public comments on the final draft FWMEP. Fort Collins has prepared
a separate memo to further address Commissioner and public comments and questions,
Appendix E. Copies of the public comments are included in Appendix F.
•On May 4, 2023, Fort Collins presented the FWMEP to the Commission Meeting hosted at the
Colorado Mountain College Spring Valley at Glenwood Springs Campus, Glenwood Springs, CO,
Fort Collins and CPW staff addressed Commission comments and questions. Afterwards, two entities
provided verbal public comment on the FWMEP.
–Fort Collins has prepared a separate memo to further address Commissioner and public
comments and questions, Appendix E. In addition, the two entities that provided verbal
comments later provided written public comment on the FWMEP. The information proved by
the Commission, public entities, and individuals were used to revise the Final FWMEP Copies
about the public comment can be found in Appendix F.
•Commission Meeting (location) note to reviewers: Location, date and summary to be added after
this event occurs. At the June 22 or 23, 2023 Commission meeting, Fort Collins will present the final
FWMEP to the Commission for its consideration as the Commission’s recommendation regarding the
mitigation of fish and wildlife resources from the Halligan Project.
•CWCB meeting: The Halligan FWMEP will be presented to the CWCB at their July 2023 board
meeting.
EXHIBIT A TO RESOLUTION 2025-083
2 Fort Collins Water Portfolio
2.1 Existing Water Supply and Demand
Fort Collins, through Fort Collins Utilities, is one of several water providers in Fort Collins’ municipal
boundaries and growth management area. Fort Collins generally provides water service to the central
portion of the Fort Collins community. Various water districts provide water service to the other
portions of the Fort Collins community. The water service areas for Fort Collins and the neighboring
water districts are shown on Figure 2-1.
Fort Collins’ water supplies are surface supplies and come from two physical systems: the Poudre River
watershed and Horsetooth Reservoir.3 Fort Collins diverts water from the Poudre River watershed into
its system on the Main Stem at the Fort Collins Intake(s). These supplies are primarily native Poudre
River water, but also include some water from the Colorado, Michigan, and Laramie rivers. Fort Collins
also diverts water at other locations to irrigate parks, golf courses, two cemeteries, greenbelt areas, and
some schoolgrounds, as well as to meet contractual raw water delivery obligations and to meet return
flow and other obligations. Fort Collins also takes delivery of water from Horsetooth Reservoir at the
Soldier Canyon Outlet. These supplies are primarily Colorado River water from the Colorado–Big
Thompson (C-BT) Project and Windy Gap Project. Fort Collins’ water system is described in greater detail
in the DEIS. Certain aspects of Fort Collins’ system are shown on Figure 2-1.
Fort Collins treats water from the Poudre River watershed and Horsetooth Reservoir at the Fort Collins
Water Treatment Facility. The treated water is then delivered to Fort Collins’ customers through
approximately 540 miles of pipeline to over 34,000 taps. Fort Collins’ customers include residences
(single and multifamily) and commercial entities of various types. In 2014, Fort Collins delivered
7.4 billion gallons of water to approximately 136,500 people. In 2020, demand increased to 7.7 billion
gallons of water delivered to approximately 142,800 people.
3 Horsetooth Reservoir borders the City of Fort Collins and is an East Slope terminal reservoir in the C-BT System. More information on the C-BT
Project, which is operated and maintained by Northern Water and the U.S. Bureau of Reclamation, is provided at
https://www.northernwater.org/what-we-do/deliver-water/colorado-big-thompson-project.
EXHIBIT A TO RESOLUTION 2025-083
Figure 2-1. Fort Collins Utilities Water Supply System
Source: City of Fort Collins 2021a
EXHIBIT A TO RESOLUTION 2025-083
2.2 Water Conservation and Water Restrictions
Fort Collins has a strong commitment to ensuring the efficient and responsible use of water. Fort Collins’
water conservation program started in 1977 and continues to evolve to support the community in using
water efficiently. Some of Fort Collins’ water conservation efforts are detailed in the DEIS, as well as
Fort Collins’ 2015 Water Efficiency Plan (City of Fort Collins 2015a). Fort Collins’ conservation efforts
include metering of all customers and a customer data portal; customer leak notifications; free irrigation
system audits and home water assessments; irrigation and fixture equipment rebates; landscaper
trainings; water-efficient landscape conversion trainings and financial incentives; conservation-oriented
water rate structures; extensive customer outreach, including monthly water use reports and targeted
industry outreach; a restrictive covenants ordinance; conservation kit giveaways; and building audit.
Currently, planned efforts focus on leveraging advanced water use meter data, promoting and
supporting greater outdoor water efficiency, greater integration of water efficiency into land use
planning and building codes, expanding commercial and industrial strategies, and efforts to increase
community water literacy. Fort Collins is also updating water supply requirement costs for new
developments to improve equity while incentivizing efficient design.
Fort Collins also uses the Water Shortage Action Plan (City of Fort Collins 2020b), previously known as
the Water Supply Shortage Response Plan, to manage water shortages. As defined in the plan, water
shortage conditions occur when projected water supply is less than the anticipated water demand,
which considers required water reserves in storage and other criteria. The following events, or
combination of events, are examples of scenarios that could cause a water shortage: drought; water
quality issues, such as contamination or fire impacts; and infrastructure issues, such as broken pipeline
or water treatment facility issues.
The population and demand within Fort Collins’ water service area are expected to grow. Water
conservation efforts and water shortage management practices have helped reduce water use and
manage supply challenges. However, as discussed in the DEIS, future demand exceeds the amount of
water that could be conserved through conservation measures; therefore, the timing of when increasing
future water demand exceeds Fort Collins’ existing water supplies can be delayed through water
conservation efforts, but not avoided.
2.3 Future Water Demand
Future water demand is calculated based on a projected population growth in the Fort Collins’ water
service area, combined with projections of future potable water demand using the reliable gallons per
capita per day forecasting technique detailed in the DEIS (Corps 2019). The Corps estimated in the DEIS
that Fort Collins’ 2065 potable water demand will be approximately 38,400 acre-feet, an increase of
about 11,700 acre-feet from the 2015 potable water demand. This estimate incorporated minimized
demand based on reduced water used as a result of the water conservation and water supply
management techniques described previously.
In 2019, Fort Collins completed the Fort Collins Utilities Water Supply Vulnerability Study (City of
Fort Collins 2019a), in which the enlargement of Halligan Reservoir was assumed. That study found that
climate change is the most significant vulnerability affecting Fort Collins’ water supply. Future climate
conditions may be more impactful to Fort Collins’ ability to meet its water supply planning policy criteria
than the occurrence of any particular infrastructure outage or environmental condition simulated by the
study’s risk scenarios. However, climate change is the most difficult risk to quantify or track. Long-term
trends are difficult to measure and are obscured by the natural variability in wet and dry years.
EXHIBIT A TO RESOLUTION 2025-083
Fort Collins will participate in, or stay informed of, state and federal climate change studies to help
Fort Collins understand the trajectory of climate change in the region.
Fort Collins’ projected increases in population and water demand, coupled with the risks of climate
change causing temperature and precipitation variations, have both been identified as key
vulnerabilities to Fort Collins’ water supply. Without the additional firm yield from the Halligan Project,
the performance of Fort Collins’ water supply system would be significantly impacted, and current water
supply planning policy criteria could not be met under most future climate and demand conditions.
2.4 Related Regional Activities
This section describes regional activities that may help inform the best application or use of Halligan
Project-related mitigation in this FWMEP, including other major water supply projects in the
Poudre River watershed in various stages of planning and execution, as well as research-based initiatives
and collaborative work groups.
2.4.1 Shared Vision Planning
One element of Halligan Project planning included a Shared Vision Planning process (Lorie et al. 2010), a
7-year collaborative planning process focused on modifying planned expansions of Halligan and Seaman
Reservoirs on the North Fork to develop design strategies that would improve flows on the North Fork.
The core assumption of the Shared Vision Planning process was enlargement of both Halligan and
Seaman Reservoirs. During the process, Fort Collins worked collaboratively with the City of Greeley,
regulatory agencies, nongovernmental organizations, and other interested parties on development of
mutually beneficial and desirable solutions for both projects. However, the City of Greeley is no longer
pursuing expansion of Seaman Reservoir, and, therefore, the joint reservoir operational measures
explored in the Shared Vision Planning process are no longer available to improve flow conditions on the
North Fork. Fort Collins has nonetheless incorporated many of the other measures developed in the
process into the Halligan Project. Over 19 years of Halligan Project planning, design and operation
development, mitigation planning, and stakeholder collaboration has been completed since the Project
was initiated in 2003.
2.4.2 Fort Collins’ River Efforts
Fort Collins owns a majority of the Poudre River’s floodplain as it flows through Fort Collins and is,
therefore, engaged in a long-term effort to support a self-sustaining healthy resilient Poudre River
(Main Stem). In recent decades, Fort Collins has proactively implemented projects aimed at restoring
the river’s connection with its riparian floodplain, connecting aquatic habitats longitudinally, protecting
established instream flows, and maintaining stormwater capacity to reduce risk to Fort Collins’ assets
and public safety. While numerous projects have already been completed, it is expected that these
integrated reach-scale river restoration projects will continue into the next several decades.
In 2011, Fort Collins completed the Cache La Poudre River Natural Areas Management Plan Update
(City of Fort Collins 2011) that detailed management goals, strategies, and objectives for Fort Collins’
21 properties along the river. An update to that management plan is being developed to establish
conservation priorities and management tactics for these natural riverine habitats given contemporary
ecological stressors, management issues, and dramatic increase in recreational uses.
Fort Collins developed the Poudre River Downtown Master Plan (City of Fort Collins 2014) for the
Poudre River Main Stem in the downtown corridor (Shields Street to Mulberry Street) to improve in-
river and bankside recreation, aquatic habitat connectivity, bank protection, flood mitigation and
floodplain management, public safety and access, and transportation. The master plan provides a long-
EXHIBIT A TO RESOLUTION 2025-083
term vision for this downtown reach and identifies multiple projects to be implemented over an
extended period of time. The construction of a whitewater park in 2019 downstream of College Avenue
was the first project implemented from this plan.
In 2014, Fort Collins completed an Ecological Response Model in collaboration with a team of scientists
to better understand past, present, and potential future river conditions through Fort Collins (Bestgen
et al. 2019). This effort, along with numerous other monitoring and biological assessment initiatives,
support a community driven quest for taking a data-informed management approach to promoting a
healthy Poudre River.
In 2017, Fort Collins released the State of the Poudre River Report: A River Health Assessment (City of
Fort Collins 2017), which examined the conditions of the Main Stem from the lower portion of Poudre
Canyon through Fort Collins to Interstate (I-)25. The effort used an assessment method developed by
Fort Collins, known as the River Health Assessment Framework (City of Fort Collins 2015b, 2019b), which
was adapted from the Functional Assessment of Colorado Streams protocol (Beardsley et al. 2015).
Fort Collins has used the information related to river health and river function gained from this effort to
generally inform the measures described in this FWMEP. In 2022 to 2023, Fort Collins is teaming with
the Coalition for the Poudre River Watershed (Coalition) to create an updated River Health Assessment
Framework. The updated framework will identify the overarching framework for reporting on the river’s
health from the headwaters to its confluence, and aims to identify methods specific to topic and
location.
2.4.3 Northern Integrated Supply Project
The Northern Colorado Water Conservancy District (Northern Water) delivers raw water and operates
infrastructure that serves numerous communities in northern Colorado. Northern Water, acting through
an enterprise on behalf of 15 water providers north of Denver, is seeking a CWA Section 404 permit
from the Corps to undertake the Northern Integrated Supply Project (NISP). NISP would use conditional
water rights to divert water from the Poudre and South Platte Rivers to provide 40,000 acre-feet of new
reliable water supply annually to meet part of the participants’ future water supply needs. NISP involves
constructing two new reservoirs—Glade and Upper Galeton—with capacities of 170,000 and
45,624 acre-feet, respectively. The Corps is the lead federal agency and has been analyzing the
environmental impacts of NISP since 2004. The Corps i ssued a ROD in December 2022.
2.4.4 Poudre Runs Through It
The Poudre Runs Through It work group is a diverse group of regional leaders and experts with varying
interests in the Poudre River, including members from Fort Collins Utilities and Natural Areas. The group
convenes agricultural, municipal, environmental, recreation, business, and other stakeholders with the
goal of identifying opportunities for cooperative action to help meet their healthy river and working
river goals. The Poudre Runs Through It defines a “healthy working river” as “one that supplies the
goods and services demanded by our complex society, within the existing and evolving water rights
system and honoring existing property rights, while maintaining and improving ecological integrity and
resilience” (CSU 2020). Fort Collins shares in this goal of a healthy working river and values input from
the work group.
2.4.5 Poudre Flows Plan
The Poudre Flows Plan is a project to increase flows in the Cache la Poudre River, from the Poudre River
canyon mouth to its confluence with the South Platte River. A key aspect of the plan is to not injure or
adversely affect other water rights and existing water operations. The plan began in 2013 as an
outgrowth of the Flows Subcommittee of the Poudre Runs Through It work group. This plan is being
EXHIBIT A TO RESOLUTION 2025-083
pursued by a coalition consisting of the Cache la Poudre Water Users Association, Fort Collins, the cities
of Greeley and Thornton, CPW, CWCB, the Colorado Water Trust, and Northern Water.
Under the Poudre Flows Plan, water that was historically diverted for irrigation and other consumptive
uses will be added to the river as “augmentation water” and protected from diversion in defined stream
reaches. The Poudre Flows Plan is being pursued as a plan to augment stream flows pursuant to
CRS 37-92-102(4.5). An application for approval of the plan was filed with the Water Court on
April 29, 2021. The current sources of augmentation water for the plan are certain water rights owned
by Fort Collins and the cities of Greeley and Thornton. Additional augmentation water sources are
intended to be added to the plan after it is approved. The plan will begin operations following the Water
Court’s entry of a final decree, currently anticipated to occur in 2024.
2.4.6 Wildfire Recovery and Monitoring Efforts
The 2020 Cameron Peak and East Troublesome Wildfires are the two largest wildfires in Colorado
history. These fires combined to burn more than 400,000 acres of forested landscape. Post-fire pollution
continues to pose significant challenges to maintaining the availability and quality of Fort Collins’
drinking water supplies. Fort Collins Utilities has developed post-wildfire water quality monitoring and
recovery plans (City of Fort Collins 2021b), which outline a range of different collaborative water quality
programs to assist with addressing these pollution concerns. These programs include, for example,
targeted post-storm runoff event sampling, real-time water quality monitoring to inform water
treatment and other staff, and monitoring long-term trends to better understand watershed recovery.
Fort Collins is a partner in the Larimer Recovery Collaborative Watershed Subcommittee, which is a
diverse collaborative stakeholder group focused on watershed recovery following the Cameron Peak
Fire. The primary watershed recovery concern following the fire is hillslope erosion, and the most
effective treatment is the application of wood mulch. The subcommittee has prioritized sub-watersheds
within the burn scar for treatment based on burn severity, slope, erosion risk, and other factors, which
ultimately targets finite resources to have the greatest treatment results. In 2021, Fort Collins Utilities
helped share the cost of treatment of more than 5,000 high priority acres at a total cost of $11,353,805.
Additional priority acres will be treated in 2022. Fort Collins also continues to work to minimize the risk
of future large-scale wildfires in the Cache la Poudre Basin by investing in targeted regional cost share
collaborative wildfire mitigation projects. Priority areas identified for future treatment include areas
that drain to the North Fork upstream of Halligan Reservoir.
2.4.7 Coalition for the Poudre River Watershed
The Coalition is a nonprofit organization established with the mission of improving and maintaining the
ecological health of the Poudre River watershed through community collaboration. With the goal of
increasing watershed resiliency and health, the Coalition released the Upper Poudre Watershed
Resilience Plan Final (JW Associates, Inc. 2017). The plan describes conditions in the Upper Poudre
Watershed and identifies target areas, priorities, and actions with the overall goal of increasing
watershed resilience. The plan assesses the baseline health of the riparian and river corridor of the
Poudre River watershed upstream of the mouth of the Poudre River Canyon using a close adaptation of
the Cache la Poudre River: River Health Assessment Framework (City of Fort Collins 2015b). Fort Collins
has coordinated with the Coalition and CPW to help inform the development of the mitigation and
enhancement measures described in this FWMEP.
EXHIBIT A TO RESOLUTION 2025-083
2.4.8 Preble’s Meadow Jumping Mouse Site Conservation Team
The Poudre Site Conservation Team for Preble’s meadow jumping mouse (Zapus hudsonius preblei)
(Preble’s) was established in 2019, and comprises stakeholders organized by the USFWS representing
local communities and natural resource management partners, including private landowners and local,
state, and federal governments and agencies. The team’s goal is to facilitate the recovery of Preble’s, a
threatened species protected under the ESA, in the North Fork watershed in accordance with the
Recovery Plan Preble’s Meadow Jumping Mouse (USFWS 2018). This recovery plan focuses on abating
threats to Preble’s and promoting riparian habitat persistence, with the ultimate goal of recovering the
subspecies so that it no longer warrants listing under the ESA. Specifically, the recovery goal for the
North Fork watershed is a minimum of 57 miles of healthy, connected Preble’s habitat. Fort Collins is an
active participant in the team, supporting such efforts as outreach, recovery population habitat
selection, and site identification for riparian habitat improvements in the North Fork riparian corridor.
2.4.9 Platte River Species
Fort Collins participates in the South Platte Water Related Activities Program (SPWRAP), which outlines a
programmatic approach for USFWS Section 7 consultation that is described in the Platte River Recovery
Implementation Program. Currently, mitigation is not expected to be needed for South Platte River
depletions. If mitigation needs associated with the Halligan Project are identified during this
programmatic approach or based on USFWS consultation, they will be incorporated into the mitigation
strategy for the Halligan Project.
EXHIBIT A TO RESOLUTION 2025-083
3 Fish and Wildlife Conditions and Impacts
This chapter describes the fish and wildlife resources that are anticipated to be affected by the Halligan
Project, as identified in the DEIS and supporting technical reports (Corps 2019), the current conditions
influencing those resources, and a summary of the anticipated effects of the Halligan Project on each
resource. Background information is presented regarding the status of each resource, followed by a
summary of the potential impacts of the Halligan Project on fish and wildlife, including both beneficial
and adverse effects. Mitigation measures that Fort Collins is proposing for the Halligan Project are
described in Section 4, and enhancement measures are described in Section 5. Appendix B presents a
tabular summary of Halligan Project impacts, mitigations, and costs.
Since completion of Halligan Reservoir in 1909, operations of Halligan Dam and the North Poudre Canal
Diversion have significantly and adversely affected river flows in the North Fork and impaired
downstream aquatic habitats. Enlargement of the reservoir through the Halligan Project provides an
opportunity for Fort Collins to provide year-round flows in the North Fork through the flow-related
operational measures described in Section 4.2.1, leading to environmental benefits for fish and wildlife
in and along the North Fork downstream of the dam.
Halligan Project impacts would occur from inundation by the enlarged reservoir along a portion of the
North Fork upstream of the reservoir and at the footprint of the replacement dam. Also, impacts would
occur from construction activities, including access and materials mobilization and stockpiling, at the
replacement dam and at the North Poudre Canal Diversion. These effects would result directly from
implementing the Halligan Project. Indirect effects are those that are Project-induced but occur later in
time or are farther removed in distance. Indirect effects associated with the Halligan Project include
increased flows in most months that benefit conditions along the North Fork downstream of the dam, as
well as some impacts resulting from reduced flows on the North Fork when water is being diverted to
storage in the enlarged Halligan Reservoir. As well as reduced flows for the Main Stem in the Exchange
Reach upstream of the North Fork confluence when Halligan Releases are being diverted by exchange
into Fort Collins Intakes. Another potential indirect effect of the Halligan Project is the risk of a stress-
related die-off of Rocky Mountain bighorn sheep (bighorn sheep) (Ovis canadensis), discussed further in
Section 3.7.4.
3.1 Basis of Halligan Project Effects
The Halligan Project effects described in this FWMEP are based on detailed evaluations in the DEIS and
supporting technical reports, and further analyses conducted since the DEIS. Because of advancements
in project design, the Halligan Project effects presented in the DEIS are being revised in the FEIS. These
revisions are expected to be minor and are a refinement of the Proposed Action in the DEIS. In the DEIS,
effects estimates were based on enlargement of the existing dam to raise the reservoir level by
approximately 25 feet. Impacts in the FEIS will be determined based on the design plan summarized in
Section 1.3 of this FWMEP, which involves replacing the more than 114-year-old dam, as of 2023, with a
replacement dam constructed approximately 200 feet downstream of the existing dam. Consistent with
the dam enlargement described in the DEIS, the dam replacement presented in the FEIS and this
FWMEP would raise the existing reservoir elevation by approximately 25 feet to increase the total water
storage capacity by approximately 8,200 acre-feet, for a total enlarged reservoir volume of
approximately 14,600 acre-feet. Enlarging the reservoir would increase the current surface area of
Halligan Reservoir from 253 to 391 acres.
EXHIBIT A TO RESOLUTION 2025-083
Fort Collins anticipates developing the following infrastructure and construction areas in association
with the Halligan Project:
• Replacement of Halligan Dam, including outlet works, stilling basin, and other appurtenant
structures constructed approximately 200 feet downstream of the existing dam
• Relocation of existing overhead power lines and poles from the southwest end of the existing
reservoir to the new dam since the old power poles would be inundated during the Halligan
enlargement
• Reconstruction of the North Poudre Canal Diversion
• Partial or total demolition of the existing dam after the replacement dam is constructed
• Temporary construction areas and features, including temporarily widened roads to allow for
construction vehicle access, construction staging areas, concrete batching plant, and possible
borrow pits for concrete aggregate
• Construction of a temporary construction access river crossing below the existing dam
• Permanent remnants of construction, including waste rock piles, new access roads in the immediate
area of the reconstructed dam, and/or widened roads in limited areas where the roads cannot be
reclaimed on portions of Fort Collins’ property and/or where private property owners request to
retain widened roads
Future operation of the Halligan Project is described in Section 1.3.1.2. Features that would be
constructed as part of avoidance, minimization, compensatory mitigation, and enhancement measures
are described in Sections 4 and 5.
At this time, details of the extent, methods, and impacts related to dam demolition are not known. Fort
Collins will consult with CPW as needed on the dam demolition. Differences in Halligan Project effects
between the DEIS and FEIS are expected to be minimal.
3.2 Resources Evaluated
The following resources associated with fish or wildlife are addressed in this FWMEP:
• Surface water hydrology (Section 3.3)
• Surface water quality (Section 3.4)
• Aquatic resources (Section 3.5)
• Terrestrial wildlife, including big game (Section 3.6)
• Rocky Mountain Bighorn Sheep (Section 3.7)
• Special-status species (Section 3.8)
• Recreation (Section 3.9)
DEIS Table 4-2 lists all the resources that are addressed in the DEIS but do not necessarily relate to fish
and wildlife. More information about these resources can be found in the DEIS (Corps 2019).
3.3 Surface Water Hydrology
This section describes the current conditions and potential Project effects on surface water resources
(Halligan Reservoir, the North Fork, and Main Stem) potentially affected by changes in surface water
hydrology resulting from implementation of the Halligan Project.
EXHIBIT A TO RESOLUTION 2025-083
3.3.1 Current Conditions for Surface Water Hydrology
Snowmelt provides the largest water supply to the North Fork, with runoff primarily occurring from May
to July. The DEIS Section 3.6.2.3.1 documents a typical unregulated snowmelt flow regime for the North
Fork upstream of Halligan Reservoir; this portion of the North Fork channel is supply limited for sands
and finer gravels (Corps 2019).
Historically, NPIC captures water from the North Fork to fill the reservoir beginning in the fall and
continuing until water spills over the existing dam to the North Fork in the spring, although spilling can
occur as early as December or January. NPIC typically releases water from the existing dam outlet
structure from spring through fall, nearly draining the reservoir in most years.
As described in the DEIS Section 3.3.5 and Chapter 4 and in Section 3.3.2 of this FWMEP, Halligan
Reservoir and the North Poudre Canal Diversion affect flows. Under current operations, the North Fork
can experience many zero-flow days in both winter and summer, particularly during dry or average
hydrologic years, creating low-flow conditions and disconnected pools. The DEIS describes zero-flow
days in the North Fork below Halligan Dam in winter months when the reservoir is filling, and below the
North Poudre Canal Diversion (6 miles downstream of the reservoir) to the North Poudre Canal
Diversion turn back or confluence with the downstream tributaries in summer when water is diverted
for NPIC shareholders. Flow simulations produced for the DEIS and supporting Surface Water Resources
Technical Report (CDM Smith 2017) estimated that the North Fork downstream of the North Poudre
Canal Diversion has zero-flow days approximately 40 percent of the time during both winter and
summer months. Consequently, under current conditions, the aquatic habitat in the North Fork is
disconnected between the North Poudre Canal Diversion and the first downstream tributary inflow.
Rabbit Creek, Stonewall Creek, and Lone Pine Creek provide small inflows to the North Fork, and zero-
flow days are less common downstream of these tributaries.
For the Main Stem, the DEIS Section 3.3.6 notes that trans-basin water deliveries supply significant flows
in the Upper Poudre, while irrigation, municipal, and industrial diversions influence flows downstream of
the flow gage located near the mouth of the Poudre Canyon. Multiple dry-up locations currently exist on
the Main Stem.
Dramatic flow changes occur naturally on the North Fork in the spring and summer months during
spring runoff and summer storms, and also currently occur below Halligan Reservoir during the fall and
winter months as a result of NPIC’s ongoing and historical operations of the existing Halligan Reservoir.
CPW has raised concerns in meetings with Fort Collins that these drastic changes in conditions
associated with NPIC’s operations, particularly sudden decreases from high to low flow, can adversely
affect fish populations.
3.3.2 Halligan Project Effects on Surface Water Hydrology
The Halligan Project would result in both beneficial effects and adverse impacts on the surface water
hydrology of the North Fork and on the associated aquatic resources and river morphology (GEI
Consultants, Inc. [GEI] 2016; Western EcoSystems Technologies, Inc. [WEST] 2017b; City of Fort Collins
2017). Each of these effects is described in more detail in the following sections.
3.3.2.1 Inundation Effects
Enlarging Halligan Reservoir would increase the current surface area from 253 to 391 acres at full
storage capacity. The water surface area of the enlarged Halligan Reservoir is anticipated to fluctuate
from 200 acres to 391 acres. In the enlarged reservoir, NPIC would continue to fill and drain nearly all of
their reservoir storage capacity each year, while Fort Collins would fill and drain only a portion of the
EXHIBIT A TO RESOLUTION 2025-083
enlarged reservoir capacity. The water surface elevation of the enlarged Halligan Reservoir would
fluctuate at slower rates than the current typical rates for the reservoir.
The Halligan Project would inundate two sections on the North Fork: (1) permanent inundation of a
short (approximately 200 feet) section of the North Fork between the existing dam and the replacement
dam (Downstream Permanently Inundated 200 feet); and (2) the intermittent inundation of an
approximately 0.75 mile stretch of the North Fork upstream of the existing Halligan Reservoir (Upstream
Intermittently Inundated 0.75 mile).
•Downstream Permanently Inundated 200 Feet. During construction the aquatic community in a
short section (approximately 200-feet) of the North Fork would be temporarily disrupted during the
construction of the replacement dam in between the existing and replacement dam. In addition,
another portion of the reach, approximately 200 feet downstream of the replacement dam down to
the temporary construction river crossing, will be impacted. Once construction is complete the
approximately 200-feet between the replacement dam and the existing dam would be permanently
inundated, converting the controlled river habitat to reservoir.
•Upstream Intermittently Inundated 0.75 Mile. DEIS Sections 4.8.3.1 and 4.8.3.4.1.1 discuss the
intermittent inundation of the North Fork which would transition the aquatic environment of the
0.75-mile free-flowing (lotic) aquatic habitat to an intermittently ponded (lentic) inlet channel.
Meaning in late summer, fall, and early winter the stream would contain significantly higher levels of
fine sediment which will eliminate pool habitat and reduces cobble and gravel habitat used for fish
spawning.
The permanent inundation of the controlled stream below the existing dam and the intermittent
inundation and permanent sedimentation of 0.75 mile of natural free-flowing stream, as well as
associated lotic system functions, would be a permanent direct impact from the Halligan Project
that would eliminate existing lotic aquatic habitat upstream.
3.3.2.2 Inundation Effects on an Instream Flow Water Right
The CWCB has an instream flow water right (Water Court Case 1985CW430) on the North Fork from its
confluence with Dale Creek to the current inlet of Halligan Reservoir. The reach of the instream flow
water includes the approximately 0.75 mile of the North Fork stream that would be intermittently
inundated and permanently impacted by enlarging Halligan Reservoir, as discussed in the previous
subsection.
This inundation will cause injury to the CWCB instream flow water right. In Water Court Case
2013CW3185, Fort Collins and the CWCB reached an agreement regarding how to proceed with respect
to the instream flow water right. Key portions of that agreement are summarized in this subsection.
Fort Collins agreed to seek CWCB approval to inundate and to provide mitigation either pursuant to:
(a)Rule 7 of the Rules Concerning the Colorado Instream Flow and Natural Lake Level Program,
2 CCR 408-2; or (b) an agreement pursuant to the CWCB rules and regulations enacted under CRS
Sections 37-60-108 and 37-92-102(3).
Fort Collins has submitted to the CWCB a request to defer the CWCB’s consideration of a request to
inundate pursuant to Rule 7j of those rules and regulations. The CWCB has agreed to defer such
consideration until permitting by other state, federal, or local governmental agencies concerning the
Halligan Reservoir enlargement is completed.
If Fort Collins is required by other governmental entities to provide mitigation to offset impacts of the
Halligan Reservoir enlargement, the CWCB has agreed to consider the cumulative effects of such
EXHIBIT A TO RESOLUTION 2025-083
mitigation on the mitigation or compensation it will require as a condition of granting its approval to
inundate any portion of the CWCB instream flow water right.
3.3.2.3 Flow Effects on the North Fork Downstream of Halligan Reservoir
Indirect impacts on the North Fork downstream of Halligan Reservoir would include a minor reduction
(DEIS Section 4.3.2) in flows during peak stream flow months when water is diverted to storage in the
enlargement under Fort Collins’ various water rights decreed for storage in Halligan Reservoir, and
temporary flow effects related to dam construction. Below the replacement dam, the North Fork would
benefit from Fort Collins’ operational commitments associated with the Project, specifically the Winter
Release Plan, which provides continuous release of 3 cfs from the enlarged reservoir from October
through April to maintain flows in the North Fork below Halligan Reservoir.4 Although the Winter
Release Plan is an operational commitment and not a mitigation measure, it is described in more detail
with other flow-related operational measures in Section 4.2.1 to facilitate understanding of how all flow-
related operations will be conducted.
Based on modeling results presented in the DEIS Section 4.3.3.3.3, with the Winter Release Plan daily
mean flows in the North Fork from the replacement dam to the North Poudre Canal Diversion are
expected to increase from November through January, and from October through March for the reach
below the North Poudre Canal Diversion to at least Seaman Reservoir. The Halligan Projects’ Winter
Release Plan eliminates the zero-flow days downstream of Halligan Reservoir to the North Poudre Canal
and significantly reduces the number of months with zero-flow days both below the North Poudre Canal
and at the Livermore Gage. The Halligan Project may improve river connectivity during low-flow periods
and could increase downstream areas of riffle and pool complexes. These flow-related operational
measures would have varying beneficial effects on approximately 22 miles of the North Fork, from the
replacement Halligan Dam to Seaman Reservoir. The beneficial effects from the Winter Release Plan
would be most impactful where the North Fork currently experiences very low or no flow (for example,
below Halligan Reservoir in winter), but those benefits may diminish farther downstream where water
enters the North Fork from its tributaries (for example, Rabbit and Lone Pine Creeks).
The Winter Release Plan dedicates continuous 3 cfs releases from the enlarged Halligan Reservoir to the
North Fork from October 1 to April 30 of the following year. This operation would satisfy Fort Collins’
wintertime return flow obligations, decrease winter consumption of other water sources (that is,
Horsetooth Reservoir), and result in the concurrent environmental benefit of improving North Fork
stream flows during periods when river flows are typically low (Section 4.2.1.2).
3.3.2.4 Flow Effects on the Poudre River Main Stem
On the Main Stem both above and below its confluence with the North Fork, the DEIS Section 4.3.3.3.4
indicates that the Halligan Project’s modeled effects on-stream flows were considered within normal
variability and are not meaningful. On the Main Stem above the confluence, a minor increase in stream
flows above the Munroe Canal Diversion is expected. Below the Munroe Canal and Fort Collins pipeline
diversions to the North Fork confluence, the Halligan Project is expected to cause minor reductions in
annual stream flows as a result of diversions of Halligan Reservoir releases made by exchange. Minor
reductions have occurred year-round, but were typically highest in June and July, mostly as a result of
increased use of Fort Collins’ changed rights in the Southside Ditches. As described in the DEIS, the
Halligan Project would generally increase the fraction of water originating from the North Fork in the
Main Stem downstream of the confluence by about 4 percent on an average annual basis.
4 3 cfs would be released from Halligan Reservoir. The amount attributed to this release would be reduced by transit losses assessed by the water
commissioner.
EXHIBIT A TO RESOLUTION 2025-083
3.4 Surface Water Quality
Current conditions for surface water quality and potential surface water quality impacts of the Halligan
Project were evaluated and summarized for this plan. Areas addressed include Halligan Reservoir, the
North Fork, Seaman Reservoir, and the Main Stem.
3.4.1 Current Conditions for Surface Water Quality
Current conditions for surface water quality relevant to the Halligan Project are summarized in
Appendix C, which includes overviews of surface water quality current conditions for Halligan Reservoir,
Seaman Reservoir, the North Fork, and the Main Stem. The summary of current conditions in Appendix
C is based on information presented in the DEIS as well as detailed recent studies (Hydros 2020, 2021a,
2021b, 2021c, 2021d, and 2022b). These recent studies rigorously document the conceptualization of
existing major drivers of spatial and temporal variability in temperature and water quality based on
evaluation of observed water-quality data, flow data, diversion patterns, reservoir operations, geology,
point sources, land use, and spatially varying meteorological conditions. Appendix C is also supported by
two memoranda (Hydros 2022a and 2022c). These two memoranda were developed to document key
water-quality discussion topics from meetings held with CPW during the FWMEP development process.
3.4.2 Halligan Project Effects on Surface Water Quality
Halligan Project effects on surface water quality were anticipated based on the detailed conceptual
understandings of Halligan and Seaman Reservoirs, the North Fork, and the Main Stem as well as
consideration of Halligan Project effects on flows, as summarized in Appendix C and supported by
Hydros Consulting, Inc. (Hydros; 2020, 2021a, 2021b, 2021c, 2021d, and 2022b). Fort Collins asserts that
no water-quality impacts due to the Halligan Project are currently anticipated in Halligan Reservoir itself,
or in Seaman Reservoir. Additionally, numerous meetings5 and rounds of comments and responses were
completed with CPW and the Water Quality Control Division (WQCD) to communicate and coordinate
on anticipated surface water-quality effects.6 Key discussion topics from those meetings are
documented in Hydros publications (2022a and 2022c).
The approach to identifying potential Halligan Project surface water-quality impacts was largely based
on consideration of existing conditions and anticipated changes relative to applicable aquatic life
standards. A potential impact was anticipated if a concentration or temperature increase (or decrease in
the case of dissolved oxygen [DO]) was anticipated because of the Halligan Project, and the system is
currently either approaching or exceeding the corresponding aquatic life standard. Additionally, if a
large (considering the magnitude of the aquatic life standard) concentration or temperature increase
(or decrease in the case of DO) was anticipated to occur because of the Halligan Project, that was also
identified as a potential impact on aquatic life. Both acute and chronic aquatic life standards were
considered for temperature and water quality. Additionally, following discussions with CPW, literature-
based iron concentrations below the currently applicable chronic total iron standard for aquatic life
were also considered as thresholds of potential concern for chronic dissolved iron below Halligan
Reservoir (refer to Section 3.4.2.5). In this process, iron stands as a unique case of consideration of
potential impacts relative to values more stringent than current standards.
The rationale for this largely standards-based approach is that, for temperature and water quality,
aquatic life regulations provide an existing, enforceable, quantifiable, state-specific regulatory basis for
the identification of impacts. Fort Collins recognizes that state standards do not necessarily provide
5 Fort Collins met with CPW to discuss surface water quality on the following dates: July 9, 2020; February 3, 2022; February 17, 2022; February 24, 2022;
April 14, 2022; May 3, 2022; May 17,2022; May 20, 2022; July 18, 2022; and September 9, 2022.
6 Note that the analyses to be completed to identify impacts for the 401 Certification Application will differ from those completed for the FWMEP.
EXHIBIT A TO RESOLUTION 2025-083
guidelines for the identification of impacts for the FWMEP for other resources areas (for example,
surface water hydrology, aquatic resources, terrestrial wildlife, special-status species, and recreation)
and that CPW may have additional concerns about potential Project effects on aquatic resources and
wildlife that are not fully addressed by a standards-based approach but that may be addressed through
this FWMEP. To understand and evaluate these additional potential concerns, Fort Collins and their
technical consultants engaged in numerous meetings5 with CPW and the WQCD to discuss water quality
and temperature current conditions, the approach to identifying potential water quality impacts, and
the potential impacts identified. One outcome of these discussions, as noted previously, is the
consideration of a threshold more stringent than existing standards as a special-case exception for iron
below Halligan Reservoir, in response to CPW’s expressed concerns regarding the protectiveness of the
existing aquatic life standard for this constituent.
Additional temperature and water quality modeling is planned for the CWA Section 401 water quality
certification process. This includes temperature modeling of the North Fork and Poudre River Mainstem,
as well as temperature and water quality modeling of Halligan and Seaman Reservoirs. Note that
modeling for Halligan Reservoir will simulate the effects of the relocation of the dam and the selected
demolition plan. Modeling results will allow for more definitive determination of any long-term water-
quality impacts associated with the new dam configuration that are not anticipated at this time.
Modeling for the CWA Section 401 water quality certification process will also support the
antidegradation analysis. Antidegradation analyses will allow for the identification of smaller-scale
impacts, if present, relative to the baseline available increment, which cannot be reliably identified
before numerical modeling. Any antidegradation impacts (including those relative to aquatic life
standards) will be evaluated as part of the CWA Section 401 water quality certification application.
Further, per the 2017 Memorandum of Understanding (CDPHE and CDNR 2017), intended to streamline
the state’s role regarding FWMEP and CWA Section 401 water quality certification permitting for water
supply projects, CPW may coordinate with CDPHE on the CWA Section 401 water quality certification,
including development of conditions. Therefore, in the event that additional aquatic life surface water-
quality impacts are identified through modeling and associated antidegradation analysis to be
conducted for the CWA Section 401 water quality certification process, CPW will have an opportunity to
participate in development of appropriate CWA Section 401 water quality certification conditions for the
Halligan Project. If the additional temperature and water quality modeling demonstrates that there are
impacts on aquatic life that will not be addressed in the CWA Section 401 water quality certification,
Fort Collins will work with CPW to develop additional mitigation measures as needed.
The following subsections describe each of the currently anticipated potential surface water-quality
impacts of the Halligan Project. Additionally, the rationale for not anticipating DO impacts downstream
of Halligan Reservoir is provided. A range of other key constituents/locations were considered, but
ultimately no impacts are anticipated, as documented in recent memoranda to CPW (Hydros 2022a
and 2022c). These memoranda reflect information presented in various communications and meetings
with CPW.
3.4.2.1 Water Temperature on the North Fork from Halligan Reservoir Dam to Seaman
Reservoir
Decreased summer flow rates at times because of the Halligan Project could cause or contribute to
existing summer temperature exceedances (acute and chronic) in the North Fork between Halligan
Reservoir and Seaman Reservoir. These impacts would be expected to occur at times in the months of
July through September, varying by year, depending on hydrology.
EXHIBIT A TO RESOLUTION 2025-083
3.4.2.2 Water Temperature on the North Fork Below Seaman Reservoir
Decreased summer flow rates at times because of the Halligan Project could cause or contribute to
existing summer temperature exceedances (primarily chronic, but also potentially acute) in the CWA
Section 303(d)-listed reach of the North Fork below Seaman Reservoir. These impacts would be
expected to occur at times in the months of July through September, varying by year, depending on
hydrology.
3.4.2.3 Dissolved Oxygen Below Halligan Reservoir
Recognizing the anticipated increase in residence time for Halligan Reservoir with the Halligan Project
(that is, roughly doubling average monthly residence time through the summer based on modeled flows
from 1980 to 2005; Figure 3-1; Hydros 2022a), the potential for low DO (that is, at levels of concerns to
aquatic life) in releases from Halligan Reservoir was considered but ruled out as an anticipated impact.
This section explains the considerations behind that decision.
Figure 3-1. Average Monthly Residence Times With and Without the Halligan Project Based on
Common Technical Platform Flows, 1980–2005
There is the potential that DO concentrations in the hypolimnion of Halligan Reservoir could decrease in
some years in the summer because of the Halligan Project. The magnitude of this potential effect is
uncertain but expected to be relatively small, given the competing factors associated with the reservoir
expansion. These competing factors include an increase in summer residence time (more time for
oxygen consumption in the hypolimnion through decay of organic matter/sediment oxygen demand), a
potentially larger hypolimnion (providing a greater volume for dilution of any oxygen effects), and
possible cooler bottom temperatures (slowing the rate of organic matter decay).
It is acknowledged that the net result of these competing factors could result in a small decrease in DO
at the bottom of Halligan Reservoir. However, any such decrease is not expected to cause DO
EXHIBIT A TO RESOLUTION 2025-083
concentrations to reach levels of concern for aquatic life below Halligan Reservoir for two reasons. First,
in spite of existing cases of observed low DO in the Halligan Reservoir hypolimnion during stratification,
there are no observed cases of DO concentrations approaching levels of concern (aquatic life standards)
in the North Fork at the sampling location below the dam (NBH). Therefore, any small changes to DO at
the bottom of Halligan Reservoir are unlikely to result in major changes at NBH that would cause
concern. Second, there are plans to include passive aeration into the design of the new Halligan
Reservoir dam outlet, as described in Section 4.2.2. This passive aeration should increase the rate of
reaeration of releases, addressing any small decrease in DO that may occur because of the Project.
Based on this, DO below Halligan Reservoir is discussed here, but it is not identified as an anticipated
adverse impact of the Halligan Project. This anticipated response will be further evaluated
(quantitatively) as part of the modeling planned for the CWA Section 401 water quality certification
process.
3.4.2.4 Sediment Below Halligan Reservoir
Careful management of existing sediment in Halligan Reservoir is needed during construction of the new
dam and for long-term operations of the reservoir with the Halligan Project. Without such construction
and operational planning, it is possible that a detrimental sediment release event could occur.
3.4.2.5 Iron Below Halligan Reservoir
As described in Appendix C, CPW has raised concerns that the current iron standard for aquatic life is
not adequately protective7 and that existing concentrations below Halligan are currently above levels of
concern identified in recent literature (Cadmus et al. 2018). There is the potential that iron
concentrations below Halligan Reservoir could increase in late summer with the Halligan Project
because of increased duration of stratification and corresponding increased internal loading from
sediments (though there is no concern that iron concentrations would approach the current aquatic life
iron standard). CPW has expressed specific concerns about deposition of iron below Halligan Reservoir
having the potential to inhibit periphyton growth and directly interfere with benthic macroinvertebrates
and early life stages of fish. While there are no observations of iron deposition/precipitation onto
benthic material below the current Halligan Dam, CPW is concerned this may occur in the future with
the Halligan Project.
3.4.2.6 Water Temperature on the Main Stem from Munroe Canal Diversion to the
North Fork
Halligan Project diversions at the Fort Collins Intakes could cause and/or exacerbate chronic summer
temperature standard exceedances in most years by causing slight warming in a reach that already
exhibits exceedances of temperature standards. These impacts would be expected to occur in the
months of July through September, varying by year, depending on hydrology. Note that the majority of
Halligan Project diversions from the Main Stem would occur at the Fort Collins pipeline diversion (as
opposed to the Munroe Canal Diversion upstream). Therefore, the primary focus reach for this
anticipated potential impact is the approximately 0.5 river mile reach from the Fort Collins pipeline
diversion to the North Fork confluence. There will also be decreased flows (and corresponding increases
in summer temperatures) in the 0.9 river mile reach between the Munroe Canal Diversion and the Fort
Collins pipeline diversion, but the greater effects on flow rates and temperatures are expected to occur
between the Fort Collins pipeline diversion and the North Fork confluence.
7 Note that, while CPW has expressed concerns with the existing aquatic life standard for total iron, WQCD has made it clear that the existing standards
will be the basis for analysis in the HWSP 401 Certification Application, and a 251 ug/L will not be considered in that analysis as an aquatic life standard
for total iron.
EXHIBIT A TO RESOLUTION 2025-083
3.4.2.7 Water Temperature on the Main Stem from North Fork to Hansen Supply Canal
Halligan Project diversions at the Fort Collins Intakes could cause and/or exacerbate chronic summer
temperature standard exceedances in most years by causing slight warming in the reach from the
North Fork to Hansen Supply Canal that already exhibits exceedances of temperature standards.
These impacts would be expected to occur in the months of July through September, varying by year,
depending on hydrology.
Note that no adverse effects to water temperature on the Main Stem downstream of Hansen Supply
Canal are anticipated from the Halligan Project. The small warming effects anticipated upstream of
Hansen Supply Canal are not expected to cause issues downstream of Hansen Supply Canal because of
the cooling influence of Hansen Supply Canal inflows in the summer months. As noted in Section 3.4.2,
Hansen Supply Canal releases comprise a large fraction of summer flow where it enters the Main Stem
(averaging 42 percent for July to September), making the river less sensitive to small changes in flow
rates through Poudre River Segment 10b.
In spite of the combined effects of increased amount of diversions at Munroe Canal and Fort Collins
pipeline diversions with increased summer flows from the North Fork, adverse water quality effects
from the Halligan Project, in terms of aquatic life, are not anticipated on the Main Stem below the
North Fork. While the Halligan Project will change the fraction of flow in the Poudre River coming from
the North Fork, the changes are expected to be small (Figure 3-2). As noted in Section 3.4.2, the largest
differences in water quality between the North Fork and the Main Stem upstream of the North Fork
occur in summer months, but minimal percent changes in North Fork contributions to Main Stem flows
are expected in summer (Figure 3-2). Additionally, these small percent flow changes in summer are at
the time of year when the North Fork contributes the smallest percentage to the Main Stem, further
minimizing effects on Main Stem water quality. Beyond monthly average effects, review of individual
years of modeled flows with and without the Halligan Project show minimal changes to the resulting
distribution of flow contributions from the North Fork to the Main Stem, particularly in summer months
(Hydros 2022). In short, the small anticipated changes in the fraction of flow from the North Fork would
not be expected to cause a notable shift in water quality on the Main Stem, particularly given the fact
that no aquatic life water-quality standards (other than temperature) are currently being approached or
exceeded on either the North Fork or the Main Stem downstream of the North Fork.
EXHIBIT A TO RESOLUTION 2025-083
Figure 3-2. Average Monthly Percentage of Flow from the North Fork on the Main Stem below the
North Fork Confluence[a]
[a] Based on modeled flows of future conditions with and without the Halligan Project, 1980 to 2005. Modeled flows
reflect the combined Halligan Project effects of increased diversions upstream of the North Fork and changes to
flow patterns from the North Fork to the Main Stem. Note that these flows include the Summer Low-flow Plan
and Winter Release Plan (these are incorporated into all modeled flows with the Halligan Project), but these
flows do not include an agreement with the City of Greeley for immediate pass-through of those mitigation flows
through Seaman Reservoir.
3.5 Aquatic Resources
Aquatic biological resources include fish, benthic macroinvertebrates, periphyton, and aquatic plant
communities and their habitat. The suitability of a stream to support aquatic resources is influenced by
multiple factors, including hydrology (Section 3.3) and water quality (Section 3.4), geomorphology, and
riparian vegetation. The North Fork below Halligan Reservoir provides mountain-to-plains transitional
habitat suitable for small-bodied native fish, as well as trout and other species. Throughout consultation
with CPW (for example, meetings between CPW and Fort Collins in fall 2020) for the Halligan Project,
CPW indicated that their primary focus for the North Fork below Halligan Reservoir is to protect small-
bodied native fish species and rainbow trout. This section describes the geomorphology and currently
present fish species assemblages in the North Fork to provide a baseline understanding of current
conditions for aquatic resources, with a particular focus on small-bodied native fish and rainbow trout.
3.5.1 Current Conditions for Aquatic Resources
The DEIS Section 3.8.5 describes modified flow regimes and habitat conditions in the North Fork
compared to historical conditions because of the operation of Halligan Reservoir, built in 1909, and the
Seaman Reservoir, built in 1941. DEIS Section 3.8.5 states that currently, stream habitat upstream of
Halligan Reservoir includes a mix of approximately half riffles and half pools, and runs-glides. The banks
are stable, and the substrate is a mix of gravel, cobble, and boulders. There was not excessive
EXHIBIT A TO RESOLUTION 2025-083
sedimentation of the substrate (Corps 2019). Halligan Reservoir, the North Fork flows through Phantom
Canyon, which laterally confines the river channel with little to no overbank/floodplain areas. A notable
transition in river condition occurs within Phantom Canyon at the North Poudre Canal Diversion;
immediately downstream of the North Poudre Canal Diversion, the thalweg becomes indistinct, and the
North Fork is often dry, filled with bed material, and heavily encroached by vegetation. As described in
the DEIS and summarized in Section 3.3.1, the total flow of the North Fork is sometimes captured by the
North Poudre Canal Diversion, and releases from both the Halligan and Seaman Reservoirs are
sometimes reduced to zero, leading to zero-flow days and dry-up points throughout the year. In the dry
sections, habitat for aquatic organisms is temporarily eliminated, although some of the functions of
stream habitat persist in a limited way through the dry periods (for example, some organisms can find
limited habitat refuge in isolated pools or by burrowing into moist substrate, and isolated sections of
deep pools and upwelling groundwater are present downstream of the North Poudre Canal Diversion
that provide refuge).
The DEIS Section 3.8.3.4 summarizes fish survey data from 1959 through 2017 based on the presence of
species and relative abundance. The North Fork supported mostly warmwater fish in terms of number of
species, but brown trout (Salmo trutta) was often the most abundant during recent sampling events
(CPW 2018).
Species assemblage data (unpublished), collected between 1960 and 2019 (CPW 2020a) was analyzed to
identify specific small-bodied native fish of interest in the North Fork that may be potentially affected by
shifting operational strategies. The fish survey of the North Fork used for analysis was conducted during
November 2017 (CPW 2018). Information obtained from the 2017 Fishery Sampling Survey Summary
provides the information about the fish communities in the North Fork below Halligan Reservoir.
Despite the altered flow regime in the North Fork, the 2017 Fishery Sampling Survey Summary notes
that the fishery within Phantom Canyon has maintained a viable trout population and native fish
component. These fish sampling efforts indicated high densities of introduced salmonids and small-
bodied native fish. Five species native to the drainage were collected in 2017 in the North Fork below
Halligan Reservoir and above the North Poudre Canal Diversion. Of those five native species, only two
were observed downstream of the North Poudre Canal Diversion. Non-native species were found both
above and below the North Poudre Canal Diversion.
Unpublished data provided by CPW (CPW 2020a) collected over the past 59 years on the North Fork
between Halligan and Seaman Reservoirs, including the 2017 study described in the previous paragraph,
identified the following species in the North Fork:
• Native species: black bullhead (Ameiurus melas), creek chub (Semotilus atromaculatus), green
sunfish (Lepomis cyanellus), Iowa darter (Etheostoma exile), johnny darter (Rhinichthys cataractae),
fathead minnow (Pimephales promelas), longnose dace (Rhinichthys cataractae), longnose sucker
(Catostomus larkiaus), and white sucker (Catostomus commersonii).
• Introduced species: brook stickleback (Culaea inconstans), brown trout (Salmo trutta), cutbow
(Oncorhynchus larkia × mykiss), rainbow trout (Oncorhynchus mykiss), and yellow perch (Perca
flavescens).
Spawning of small-bodied native fish in the North Fork is temporally limited by seasonal water
temperatures. Species observed in the North Fork below Halligan Reservoir require temperatures that
range from 12 degrees Celsius (°C) to 29°C (Woodling 1985). Based on temperature data analyzed from
2016 to 2020 (Hydros 2021d), the North Fork below Halligan Reservoir currently maintains suitable
spawning temperatures for small-bodied native fish from approximately June to October.
EXHIBIT A TO RESOLUTION 2025-083
3.5.1.1 Current Conditions for Macroinvertebrates
DEIS Section 3.8.3.6 discusses current conditions for macroinvertebrates in the North Fork. The section
references existing macroinvertebrate data available from the CDPHE (2012), Miller Ecological
Consultants (Miller) (2009), and the Nature Conservancy (2012), along with additional data collected in
2015 by GEI in support of the DEIS (GEI 2019).
DEIS Section 3.8.3.6 summarizes the current conditions for macroinvertebrates on page 3-146:
Benthic macroinvertebrate data were available from at least one site in each segment, primarily
from the current conditions time period. In Segment 1 (below Halligan Dam), an abundant
community of invertebrates exists, including some sensitive mayfly, stonefly, and caddisfly species,
suggesting water quality is sufficient to support sensitive species. However, the number of taxa,
number of mayfly, stonefly, and caddisfly species, and diversity are lower than expected at the site
downstream of Halligan Reservoir compared to other sites in the study area, indicating the
community may be experiencing some stress. The reduced number of taxa and low diversity
downstream of Halligan Reservoir is a common characteristic of tailwater benthic invertebrate
communities due to the altered physical and chemical environment downstream of reservoirs.
The DEIS Section 4.8.3.4.2 analysis found that the macroinvertebrate multimetric index (MMI) scores
improved in Segment 1 (Halligan Reservoir Outlet to the North Poudre Canal Diversion) from 43 in 2011
to 70 to 82 in 2015 (well above the attainment threshold). MMI scores collected by GEI in 2015 in
Segment 2a (North Poudre Canal Diversion to Rabbit Creek) ranged from 76 to 79 (well above the
attainment threshold). MMI scores in Segment 2b (Rabbit Creek to Seaman Reservoir Inlet) were 47
in 2005 and 67 in 2007 (the MMI score of 67 was above the threshold for Attainment in 2007). The data
for Segment 3 (Seaman Reservoir Outlet to Confluence) suggest that the tailwater effect seen below
Halligan Reservoir is also occurring downstream of Seaman Reservoir, resulting in a high density of a few
species and relatively low diversity index values. A MMI score of 46 was calculated for the spring 2003
sample. Three samples from 2015 had MMI scores ranging from 64 to 72 (above the attainment
threshold of 52), suggesting recent improvements in the macroinvertebrate community.
No macroinvertebrate sampling has occurred above Halligan Reservoir; however, one may assume a
high MMI score in the reach above Halligan Reservoir due to the relatively pristine stream conditions
including a healthy riffle-pool plan form, boulder-cobble-gravel substrate, and natural stream hydrology.
3.5.2 Halligan Project Effects on Aquatic Resources
The Halligan Project’s influence on aquatic resources is closely tied to surface water hydrology, as
described in Section 3.3. Therefore, both the beneficial and adverse effects on aquatic resources
generally follow those described for surface water hydrology in Section 3.3. The DEIS Section 4.3.8
(Corps 2019) and supporting technical reports describe the Halligan Project’s expected beneficial and
adverse effects on the aquatic resources and river morphology of the North Fork (GEI 2016;
WEST 2017b; City of Fort Collins 2017). In the DEIS, Halligan Project effects were evaluated by predicting
the influence of flow changes on available habitat used by aquatic organisms, including riffle and pool
complexes, which are special aquatic sites identified in the Section 404(b)(1) guidelines.
As discussed above in Inundation Effects (Section 3.3.2.1), the Halligan Project would inundate two
sections on the North Fork: (1) permanent the inundation of a short (approximately 200 feet) section of
the North Fork between the existing dam and the replacement dam (Downstream Permanently
EXHIBIT A TO RESOLUTION 2025-083
Inundated 200 feet); and (2) the intermittent inundation of an approximately 0.75 mile stretch of the
North Fork upstream of the existing Halligan Reservoir (Upstream Intermittently Inundated 0.75 mile).
• Downstream Permanently Inundated 200 Feet. During construction the aquatic community in a
short section (approximately 200-feet) of the North Fork would be temporarily disrupted during the
construction of the replacement dam in between the existing and replacement dam. In addition,
another portion of the reach, approximately 200 feet downstream of the replacement dam down to
the temporary construction river crossing, will be impacted. Once construction is complete the
approximately 200-feet between the replacement dam and the existing dam would be permanently
inundated, converting the controlled river habitat to reservoir.
• Upstream Intermittently Inundated 0.75 Mile. DEIS Sections 4.8.3.1 and 4.8.3.4.1.1 discuss the
intermittent inundation of the North Fork would transition the aquatic environment of the 0.75-mile
free-flowing (lotic) aquatic habitat to an intermittently ponded (lentic) inlet channel. The transition
would result from significantly higher levels of fine sediment which will eliminate pool habitat and
reduces cobble and gravel habitat that could be used for fish spawning. DEIS Sections 4.8.3.1 and
4.8.3.4.1.1 identify the loss of approximately 0.75 mile of the North Folk, including approximately
3.5 acres of free-flowing riffle and pool complexes as major adverse effect.
DEIS Section 4.8.3.4.1.1 describes the North Fork as a coldwater stream community of fish, benthic
macroinvertebrates, and algae that would be replaced with a reservoir community as a result of the
Halligan Project. Many of the fish species, such as the recreationally important brown and rainbow
trout, would still be able to use the reservoir habitat; however, some functions such as spawning would
be eliminated in the inundated sections as described above in Section 3.3.2.1. Other species, such as
longnose dace, prefer stream habitat and likely would not use the reservoir (Corps 2019; DEIS
Section 4.8.3.4.1.1). The permanent inundation of the controlled stream below the existing dam and the
intermittent inundation and permanent sedimentation of 0.75 mile of natural free-flowing stream, as
well as associated lotic system functions, would be a permanent direct impact from the Halligan Project
that would eliminate existing lotic aquatic habitat upstream.
DEIS Section 4.8.3.4.4 describes the benefit of improved stream flows from operation of the enlarged
reservoir, including minimum winter and summer flow releases and peak flow bypasses (refer to
Section 4.2.1 of this FWMEP) for a distance of approximately 22 miles along the North Fork below
Halligan Reservoir. The DEIS Section 4.8.3.4.1.3 states that the Halligan Project would maintain instream
habitat for aquatic organisms throughout the year, thus eliminating dry riverbed conditions and
resulting in major seasonal beneficial effects for aquatic resources from Halligan Reservoir downstream
to the North Poudre Canal return flow (approximately 8 miles) on the North Fork with moderate
beneficial effects from the North Poudre Canal return flow down to Rabbit Creek (approximately
2 miles), and minor benefits extending from the Rabbit Creek down to Seaman Reservoir, a total
distance of approximately 12 miles. The Halligan Project would increase stream flows in winter and
other traditionally low-flow periods, improve river connectivity during low-flow periods from a condition
with frequent dry-up points, and increase downstream areas of riffle and pool complexes. The enlarged
reservoir operations would eliminate almost all8 zero-flow days at frequent dry-up points and minimize
extreme flow fluctuations from Fort Collins’ use of the enlargement. The DEIS notes that additional
flows would result in a more robust plant community and improve the fishery health of the North Fork.
As described in the DEIS, about 5.8 to 12.1 acres of riffle and pool complexes in the North Fork would
8 See potential exceptions at end of this section 4.2.1.1 Winter Release Plan “Curtailment of the Winter Release Plan” and section 4.2.1.2 Summer Low-
flow Plan “Curtailment of the Summer Low-flow Plan”.
EXHIBIT A TO RESOLUTION 2025-083
experience continuous flow and no zero-flow days. Table 3-1 summarizes Halligan Project effects on
riffle and pool complexes on the North Fork.
Table 3-1. Summary of Halligan Project Effects on Riffle and Pool Complexes
Area Effect Riffle and Pool
Complex Area (acres)
North Fork upstream of existing reservoir
(DEIS Section 4.8.3.4.1.2)
Loss due to inundation -3.5
North Fork between existing dam and replacement dam
(based on geographic information system [GIS] evaluation
by Jacobs)
Loss due to inundation -0.3
North Fork downstream of replacement dam to Rabbit
Creek 10 miles, which is 4 miles below the North Poudre
Canal Diversion (DEIS Section 4.8.3.4.1.3)
Benefit from year-
round flows
+5.8 to +12.1[a]
Net Effect +2.0 to +8.3[a]
[a] Varying calculations have been used to determine the area of restored riffle-pool complexes downstream of the
North Poudre Canal Diversion.
3.5.3 Wetlands
Wetlands effects are regulated under the CWA and will be addressed through the SWA Section 404
permitting process. Wetlands conditions, effects, and mitigation are regulated by the Corps. They will be
described in the FEIS, and are not addressed in this FWMEP. Fort Collins will prepare a wetlands
mitigation plan independent of this FWMEP for future authorization by the Corps as part of the CWA
Section 404 permitting process.
Wetland habitats exist around Halligan Reservoir and along the North Fork upstream and downstream
of the reservoir. Wetlands provide an important habitat type for both terrestrial and aquatic wildlife of
the region. Many species of amphibians, reptiles, birds, and mammals utilize these habitats at various
times in their life. Several of these species are uniquely adapted to these aquatic environments. Wetland
habitats are especially vital for migratory birds, and numerous big game species such as deer, elk, and
bear will commonly use wetlands for food and shelter. The DEIS notes that the net impact on wetlands
from the Halligan Project would be moderate. Although inundation would result in the long-term loss of
16.74 acres of wetland (10.92 acres of palustrine scrub-shrub wetlands, 4.89 acres of lacustrine littoral
emergent wetlands, 0.021 acre of palustrine emergent wetlands, and 0.91 acre of forested wetlands)
mostly along or below the ordinary high water mark of the existing reservoir, nearly 11 acres of wetland
are expected to re-establish along the enlarged reservoir ordinary high water mark. The Halligan Project
flow-related operational measures (Section 4.2.1) may improve river connectivity during low-flow
periods between Halligan Reservoir downstream to the North Poudre Canal return flow on the North
Fork, and provide more wetted area that would benefit approximately 22 miles of the North Fork, and
may improve riparian wetlands.
3.6 Terrestrial Wildlife Including Big Game
Habitat within the Halligan Project Area supports a diverse array of mammals, and includes undeveloped
and undisturbed forest, shrubland, and grassland areas, as well as riparian communities and wetlands.
The DEIS identifies a variety of large and small mammals that range within the Project Area, including
game species such as elk (Cervus canadensis), mule deer (Odocoileus hemionus), white-tailed deer
EXHIBIT A TO RESOLUTION 2025-083
(Odocoileus virginianus), Rocky Mountain bighorn sheep, mountain lion (Puma concolor), black bear
(Ursus americanus), and pronghorn (Antilocapra americana). Rocky Mountain bighorn sheep are
discussed in Section 3.7.
3.6.1 Current Conditions for Big Game
The DEIS describes similar conditions for big game species (elk, deer, and pronghorn). For elk, the
Halligan Project is within CPW’s Elk Data Analysis Unit E-4—the Red Feather-Poudre Canyon Elk Herd.
The primary impact on elk habitat in this data analysis unit is the growth of small acreage rural
subdivisions and the resulting loss of overall and winter elk range.
The DEIS indicates that both mule deer and white-tailed deer inhabit CPW’s Deer Data Analysis
Unit D-4—the Red Feather-Poudre Canyon Deer Herd, which encompasses the Halligan Project Area.
Similar to elk, the primary impact on deer is the growth of rural subdivisions and small acreage
developments that would result in the loss of deer overall and winter range. As described in the DEIS,
CPW identifies potential water development projects within the Data Analysis Unit D-4 as potentially
having a pronounced cumulative impact on overall and winter deer range for the Red Feather-Poudre
Canyon Deer Herd. In the early 2000s, the deer herd population objective was decreased to reduce the
prevalence of chronic wasting disease. The population objective has since been increased because
chronic wasting disease is no longer affecting the herd.
Pronghorn are common in undeveloped grasslands and shrublands of eastern Colorado, including the
area around Halligan Reservoir. The Halligan Project is within Pronghorn Data Analysis Unit PH33.
As noted in the DEIS, CPW mapped pronghorn range covering Halligan Reservoir, and has identified a
concentration area where winter population densities are greater than surrounding areas from the
eastern end of the reservoir and extending to the north and east. The DEIS notes that CPW does not
identify any significant issues related to this herd.
3.6.2 Current Conditions for Other Wildlife
The DEIS notes that grasslands and shrublands in and around the Halligan Project can potentially
support healthy populations of small mammals, such as rabbits, squirrels, chipmunks, mice, and other
rodents, and the predator species that feed on small mammals, such as coyote, fox, and badger.
Riparian areas and wetlands can support additional species, including raccoon, muskrat, meadow vole,
and Preble’s meadow jumping mouse. Deciduous trees near riparian areas, as well as rock crevices, can
provide potential roosts for bats. Rocky outcroppings also provide feeding and general cover for a
variety of animals.
3.6.3 Halligan Project Effects on Big Game and Other Wildlife
The long-term impacts of the Halligan Project on most small, medium, and large terrestrial mammals
would be negligible or not measurable. As described in the DEIS, potential long-term big game range
impacts would result from habitat inundation caused by new inundation from the enlarged reservoir
(approximately 138 acres). As a result, some terrestrial vegetation and wildlife habitat would be
replaced with open water habitat, thereby reducing habitat availability for terrestrial (for example, big
game, small mammals, and upland migratory birds) species, while increasing habitat for aquatic species
(for example, waterfowl). The access roads, borrow pits, and dam footprint would result in a smaller
permanent impact (approximately 27 acres). Temporary impacts (approximately 31.5 acres) would be
related to construction and include relocation of existing overhead power lines and poles, removal of
vegetation around the dam and reservoir, as well as facilities or areas that would be restored following
construction, including access roads and staging areas. Proposed mitigation for vegetation and habitat
loss impacts on the Cherokee State Wildlife Area (SWA) are discussed further in Section 4 of this plan.
EXHIBIT A TO RESOLUTION 2025-083
The DEIS noted that indirect effects on wildlife and big game could involve stress and displacement of
wildlife caused by noise and disturbance from construction activities, transportation of people and
materials, and general human activity in the reservoir and NPIC diversion areas. In addition, vehicle and
equipment emissions and fugitive dust also might displace wildlife. Proposed avoidance and
minimization measures for noise and construction-related activities (that is, timing restrictions for the
relocation of overhead power lines and poles at Halligan Reservoir and for the North Poudre Canal and
Calloway Diversions) are discussed in Section 4 of this FWMEP. There may be a shift in the movement of
some big game species as a result of construction activities and disturbances that could result in
increased collisions with vehicles. This displacement and disturbance of big game may place additional
stress on individuals of these species; however, the DEIS determined that it is likely to have a negligible
effect on elk, mule deer, white-tailed deer, and pronghorn populations. Wildlife resources at Halligan
Reservoir could also be indirectly affected by the possible introduction or establishment of noxious
weeds, soil erosion, and potential alteration of stream flows in the North Fork. The potential effects of
altered flows along the North Fork because of the Winter Release Plan and Summer Low-flow Plan are
expected to have an overall minor benefit to wetland and riparian vegetation on the North Fork.
Noxious weed establishment and soil erosion would affect native vegetation communities. A change in
vegetation resulting from the establishment of noxious weeds and soil erosion may result in a lower
carrying capacity for some species in the area; however, it would be unlikely to result in complete loss of
suitable habitat. However, the Project will minimize construction impacts through the development and
implementation of a noxious weed management plan and revegetation and erosion control plans. The
enlarged reservoir may also have a negligible to minor effect on wildlife movement as a result of
inundation of existing wildlife trails on the North Fork upstream of the existing reservoir. The Corps
anticipates that wildlife would acclimate quickly to these changes that would occur in the inundation
area because the existing reservoir’s water level varies seasonally.
The DEIS evaluated regional species of big game, other mammals, birds, reptiles, and amphibians for
potential effects of the Halligan Project on individual species or supporting habitat. Based on that
evaluation, it is expected that the Halligan Project would result in no or negligible adverse effects on the
following species:
• Elk
• White-tailed deer
• Pronghorn
• Black bear
• Mountain lion
• Other small, medium, and large terrestrial mammals
• Raptors
• Waterfowl
• Migratory birds
• Bats
• Amphibians
• Reptiles
In the DEIS, the Corps assumed that long-term effects such as limiting range types, and suitable habitat
within those range types, were the most relevant effects for big game species. The mule deer was the
only big game species identified in the DEIS that would experience impacts on suitable habitat within a
limiting range type as a result of the Halligan Project, with approximately 118 acres (approximately
0.09 percent) of impact on severe winter range. The DEIS notes that effects on mule deer movement
EXHIBIT A TO RESOLUTION 2025-083
from the Halligan Project, including inundation of the North Fork within the Cherokee SWA, would be
negligible to minor because known migration corridors would not be affected.
Table 3-2 summarizes permanent and temporary impacts on big game range from the Halligan Project9
relative to range type in the data analysis unit (the geographic area that includes year-round range of a
big game herd).
Table 3-2. Cumulative, Permanent, and Temporary Impacts of Halligan Project on Big Game Habitat
Range Type Range Type in the
DAU (acres), from
DEIS Table 4-55
Permanent
Impacts
(acres)[a]
Temporary
Impacts
(acres)
Range Loss as
Percentage
of DAU
Range Loss as
Percentage
of GMU[b]
(acres)
Effect
Determination
in DEIS
Bighorn sheep—
overall range
(Section 3.7)[c]
208,771 155.5 31.5 0.07% 0.15% Negligible
Elk—overall range 208,771 165.0 31.5 0.08% 0.09% Negligible
Mule deer—overall
range
1,145,320 165.0 31.5 0.01% 0.09% Minor
Mule deer—severe
winter range
128,724 165.0 31.5 0.13% 0.15% Minor
Mule deer—winter
range
613,074 165.0 31.5 0.03% 0.09% Minor
Pronghorn—
overall range
109,535 165.0 31.5 0.15% 0.73% Negligible
Pronghorn—winter
range
174,203 165.0 31.5 0.1% 0.75% Negligible
White-tailed
deer—overall
range
239,940 22.7 13.6 0.01% 0.14% Negligible
[a] DEIS Table 4-55 presents slightly lower permanent impacts (up to 132.5 acres). This table presents estimated
cumulative long-term direct effects would result from inundation (138 acres) and direct footprint impacts
associated with dam replacement construction (27 acres), for a total of approximately 165 acres.
[b] The Lone Pine bighorn sheep herd are in GMU S40, while the elk, deer, and pronghorn are part of GMU 191.
[c] The DEIS based bighorn sheep impacts on DAUs RBS-1 for an overall range area of 208,771 acres. Based on input
from CPW, bighorn sheep range has been further evaluated in this FWMEP based on the GMU level for the Lone
Pine herd, as described in Section 3.7. Based on that analysis, Project-related habitat loss for bighorn sheep may
be up to 0.15 percent of overall range.
DAU = data analysis unit
GMU = game management unit
9 Permanent impacts on big game range presented here differ slightly from the impacts listed in Table 4-55 of the DEIS because of updated dam
design elements.
EXHIBIT A TO RESOLUTION 2025-083
3.7 Rocky Mountain Bighorn Sheep
3.7.1 Current Conditions for Bighorn Sheep
Halligan Reservoir lies within the known overall range and habitat use area of the Lone Pine bighorn
sheep herd (also known as the S40 Herd). According to CPW, the Lone Pine herd is a low-elevation herd
that uses a range of habitat throughout the year. CPW has expressed concerns that the current CPW
species activity mapping (SAM) for the Lone Pine herd is incomplete based on recent CPW data
collection efforts; thus, CPW has advised Fort Collins to use caution when applying CPW SAM data to
this herd.
The current population of the Lone Pine herd has declined from an estimated 35 bighorn sheep in 2016,
to 15 bighorn sheep in 2021. The cause for the population decline is unknown (CPW 2021b). Range maps
based on the CPW SAM data were evaluated in the DEIS and indicate that Halligan Reservoir is within
the bighorn sheep overall and summer range. Anecdotal evidence referenced in the DEIS has
subsequently been confirmed by CPW that bighorn sheep use the area below Halligan Dam, Phantom
Canyon, and adjacent habitat, and are frequently seen approximately 2.5 miles south of Halligan
Reservoir and approximately 1 mile west of Phantom Canyon Ranch near Calloway Hill. In addition,
members of Lone Pine herd use a linkage area that connects habitat east of Highway 287 to Phantom
Canyon and farther southwest to the Lower Cherokee and Lone Pine units of the SWA. The bighorn
sheep habitat areas as provided by CPW have been identified on Figure 3-3.
3.7.2 Lone Pine Herd Additional Data Evaluation
Fort Collins performed an additional evaluation of bighorn sheep conditions to support discussions with
CPW. Figure 3-3 shows the best available data on the Lone Pine herd that were reviewed for the Halligan
Project and mitigation strategy development. The habits of this herd, including home range, habitat use,
production areas, and natural movement routes, have not been thoroughly studied. However,
compilation of available data and local observations indicate that the Lone Pine herd covers more than
approximately 16 square miles of viable habitat near the Halligan Project. CPW is using trail cameras and
radio collars to collect Lone Pine herd range and movement data. This data collection is ongoing, and
CPW does not expect to have quantitative data available in the near term (CPW 2021a).
EXHIBIT A TO RESOLUTION 2025-083
Figure 3-3. Halligan Project Elements and Bighorn Sheep Suitable Habitat
EXHIBIT A TO RESOLUTION 2025-083
The following summarizes the current understanding of the Lone Pine herd range and habits around the
Halligan Project Area.
• Upstream of Halligan Reservoir–Based on CPW data (CPW 2021b), the Lone Pine herd uses
available habitat in the Cherokee Park area. Bighorn sheep have been documented as far north as
the Middle Unit of the Cherokee SWA, Phantom Canyon, and south of County Road 74E (Red
Feather Lakes Road).
• Halligan Reservoir–The extent of herd range use at and near the Halligan Dam is not well
understood. To date, the areas immediately adjacent to Halligan Reservoir near the existing dam
have not been mapped as suitable habitat by CPW (Figure 3-3). Suitable habitat is determined based
on vegetative and topographical habitat features, namely steep rocky slopes with escape cover near
open areas suitable for grazing. Field observations from CPW staff and the public indicate that
bighorn sheep cross Phantom Canyon below Halligan Dam generally between North Poudre Canal
Diversion and the Calloway Diversion with increased presence in the spring and fall months.
• North Fork downstream of Halligan Reservoir–Trail camera images and field observations
document Phantom Canyon use by the Lone Pine herd throughout the year. Bighorn sheep are
frequently seen approximately 2.5 miles south of Halligan Reservoir and approximately 1.0 mile
west of The Nature Conservancy’s Phantom Canyon Ranch near Calloway Hill. The linkage area that
connects the habitat east of Highway 287 along Stonewall Creek and the ridgeline to Phantom
Canyon where it then widens in the vicinity of Calloway Hill on to the Cherokee SWA, including parts
of Rabbit Creek Ranch. This linkage area is important because it provides suitable temporary
habitats and allows for the movement of individuals or the Lone Pine herd population to known
larger suitable habitat patches across a fractured landscape.
Surrounding areas–Ram bands have been seen east of Highway 287 along Stonewall Creek using
prominent escarpments (Steamboat Rock area), and with annual fidelity, the herd uses private lands
east of the Lone Pine Unit of the Cherokee SWA and east of Phantom Canyon. Near Stonewall Creek
upstream of its confluence with the North Fork, local residents have observed individual rams annually
from approximately March to October, east of Highway 287 on the 10-mile parcel of Roberts Ranch, as
far north as the Steamboat Rock land feature, and east to approximately 1.0 mile east of Steamboat
Rock. Rams have been hit and killed by vehicles on Highway 287 in this area (Thode, pers. comm. 2021).
3.7.3 Lone Pine Herd Management Challenges
According to CPW (CPW 2021b), an existing and ongoing challenge in managing the Lone Pine herd is
the known proximity to domestic sheep grazing, which has the potential to introduce disease to wild
bighorn sheep. Several land managers within the Lone Pine herd-occupied range along the North Fork
River corridor use domestic sheep and goats for weed management. Although domestic sheep can be an
effective vegetation management tool, this practice increases the chance of commingling between the
Lone Pine herd and domestic sheep. Domestic sheep grazing has been occurring seasonally from late
April through mid-July since 2016 on private land within the range of the Lone Pine herd. The greatest
concern of commingling between the Lone Pine herd and domestic sheep is the transmission of deadly
pathogens between domestic sheep populations and bighorn sheep. Fort Collins staff have been
exploring opportunities to effectively separate the Lone Pine herd and domestic sheep in this area for
several years; however, because of local interest, domestic sheep management practices have not
changed in this area.
An additional challenge identified by CPW is the degradation of bighorn sheep habitat on the Cherokee
SWA’s Lower Unit, Roy Brown Unit, and Lone Pine Unit over the past decade caused by invasive
EXHIBIT A TO RESOLUTION 2025-083
cheatgrass (Bromus tectorum). Cheatgrass has diminished the quality of bighorn sheep habitat on the
landscape where once high-value bighorn sheep habitat occurred. Figure 3-3 shows the best available
data on the Lone Pine herd that have been reviewed for the Halligan Project and mitigation strategy
development.
3.7.4 Halligan Project Effects on Rocky Mountain Bighorn Sheep
The direct and indirect effects from the Halligan Project described for terrestrial wildlife and big game in
Section 3.6 generally apply to bighorn sheep. The DEIS notes that severe winter range is the limiting
range type for bighorn sheep. As noted in the DEIS, because there is no loss of bighorn sheep severe
winter range, both long- and short-term direct effects of the Halligan Project on bighorn sheep would be
negligible, with no measurable or perceptible consequences to the Lone Pine herd from long-term
habitat loss created by inundation.
However, CPW has asserted that the Lone Pine herd in the affected area is a low-elevation herd that has
no defining seasonal range. This herd uses the different habitat types within the entire bighorn sheep
range throughout the year based on the specific habitat requirements needed at the time. The overall
habitat has a multitude of foraging, lambing, resting, mating, thermal cover, and predator avoidance
areas that are used many times throughout the year in no specific season. Relative to direct permanent
effects, the Lone Pine herd’s S40 Unit has a total area of 272,892 acres, of which 99,286 acres are
mapped as overall range for bighorn sheep. Direct habitat loss (155.5 acres) from the Project within the
S40 Unit amounts to 0.15 percent loss of overall range within the Lone Pine herd’s S40 Unit.
Indirect effects and temporary direct effects on bighorn sheep and other big game could involve
displacement caused by noise and disturbance from construction activities, transportation of people and
materials, and general human activity in the reservoir and NPIC diversion areas. In addition, vehicle and
equipment emissions and fugitive dust may have an effect on bighorn sheep distribution. Displacement
of bighorn sheep and emissions of dust may increase the likelihood of respiratory distress, making
bighorn sheep more susceptible to disease. There may be a shift in the movement of bighorn sheep as a
result of construction activities. The DEIS also acknowledges that a potential indirect impact of Halligan
Dam rehabilitation is stress-related die-off of bighorn sheep. The DEIS Section 4.12.22, originally
determined that indirect effects from Halligan Dam rehabilitation would be moderate. This was largely
because of limited documentation of bighorn sheep in the vicinity of Halligan Reservoir, and because the
Halligan Project Area is outside any known bighorn sheep concentration area and is a small part of the
overall range.
CPW has recently collected data indicating that rams use the lower Phantom Canyon area. However,
effects are expected to be minimized because the majority of work activity will be outside this resident
bighorn sheep production area and work in the lower Phantom Canyon area would occur during winter
months when there is minimal bighorn sheep activity in the area and domestic sheep and goats are not
grazing on open range. In DEIS Section 4.12.2.2 the Corps recognized that the risk to bighorn sheep is
difficult to predict because of the lack of site-specific data and factors unrelated to the Halligan Project,
such as disease and drought. The Corps further noted that if the Halligan Project caused a die-off similar
to what happened at Waterton Canyon (75 percent to 85 percent and 2-year continued lamb mortality),
it would be a major long-term (greater than 20 years) indirect effect on the local bighorn sheep herd
that may or may not be permanent.
CPW provided specific concerns regarding impacts on bighorn sheep posed by Halligan Project
construction activities at the dam and the North Poudre Canal Diversion in a memorandum dated
January 11, 2021 (CPW 2021a) and expanded upon these concerns in subsequent meetings with
Fort Collins.
EXHIBIT A TO RESOLUTION 2025-083
CPW identified two primary concerns for adverse impacts on bighorn sheep:
• Direct disturbance and stress from construction activities–Construction activities may disrupt
bighorn sheep feeding or movement and can be negatively affected by fugitive dust, which can
increase stress and the likelihood of disease.
• Seasonal movement disruption causing increased risk for commingling with domestic sheep–
Construction activities could disrupt or alter bighorn sheep movements and push the Lone Pine herd
into nearby domestic sheep and goat grazing allotments; this would increase the chance of
commingling and pathogen transfer between domestic and bighorn sheep. This could increase the
chance of a disease outbreak and a potential bighorn sheep die-off; the likelihood of disease
outbreak increases even further when combined with the added stress from construction general
habitat disturbances.
These temporary construction-related impacts could exacerbate the conditions in which bighorn sheep
may commingle with domestic sheep used for weed management within the Halligan Project Area.
3.8 Special-status Species
The DEIS describes terrestrial species of concern that could be affected by the Halligan Project. These
species of concern are federally listed as threatened or endangered under the ESA; identified as
sensitive by the BLM; listed as threatened, endangered, or of special concern by Colorado; or listed as a
Tier 1 species in Colorado’s State Wildlife Action Plan (CPW 2015), which are species of highest
conservation priority in the state. The DEIS focuses on those species that (1) have suitable habitat
present within the Project Area (that is, within construction or inundation footprints); and (2) have been
documented in the Project Area or their distributional range overlaps the Project Area according to
CPW, Colorado Heritage Program datasets, or site-specific surveys. Available information about current
conditions and potential impacts from the Halligan Project on special-status species is summarized in
the following sections. Table 3-3 lists federal or state species of concern and summarizes the potential
effects from the Halligan Project on each species based on the DEIS evaluation.
Table 3-3. Summary of DEIS Impact Evaluation of Halligan Project on Species of Concern
Species Concern Listing Impact of Halligan Project on Each Species, from
DEIS[a]
Preble’s Federal and State,
Threatened
Major impact; will be addressed through ESA
consultation process and not included in this
FWMEP
Ute ladies’-tresses orchid
(Spiranthes diluvialis)
Federal, Threatened No effect; will be addressed through ESA
consultation process and not included in this
FWMEP
American white pelican (Pelecanus
erythrorhynchos)
BLM sensitive
species
Minor benefit
Platte River Species (Five Species) Federally listed Unperceivable; will be addressed through ESA
consultation process and not included in this
FWMEP
Rocky Mountain bighorn sheep State Tier 2, BLM
sensitive species
Negligible direct effect, possibility of moderate to
major indirect effect; discussed in Section 3.7[b]
EXHIBIT A TO RESOLUTION 2025-083
Species Concern Listing Impact of Halligan Project on Each Species, from
DEIS[a]
Northern pocket gopher
(Thomomys talpoides macrotis)
State, SOC Minor effect, discountable and insignificant
River otter (Lontra canadensis) State, Threatened Minor benefit
Townsend’s big-eared bat
(Corynorhinus townsendii
pallescens)
State SOC, BLM
sensitive species
Minor effect
Bald eagle (Haliaeetus
leucocephalus)
State SOC, BLM
sensitive species
No permanent direct effects; minor benefit from
increased foraging habitat
Golden eagle (Aquila chrysaetos) State Tier 1, BLM
sensitive species
Discountable and insignificant
Northern leopard frog (Lithobates
pipiens)
State Tier 1, State
SOC
Minor benefit
Common garter snake (Thamnophis
sirtalis)
State Tier 2, State
SOC
Minor benefit
[a] Impacts are summarized here as none, beneficial, low, or moderate, based on detailed descriptions provided in
the DEIS.
[b] CPW has stated their concern that potential impacts on bighorn sheep could range from moderate to severe
should a herd die-off occur.
SOC = species of concern
3.8.1 Current Conditions for Federally Listed Species
3.8.1.1 Preble’s Meadow Jumping Mouse and Habitat
Preble’s is a federal- and state-listed threatened species in Colorado. Pioneer Environmental Services
(Pioneer) conducted an extensive trapping survey at Halligan Reservoir for Preble’s meadow jumping
mice between June and August of 2003 (WEST 2017a), which documented the presence of Preble’s
around the reservoir. Critical habitat for Preble’s is designated along the lower portions of the North
Fork starting at Halligan Dam and includes its tributaries and portions of the Poudre River. The enlarged
Halligan Reservoir inundation area upstream of the existing dam is outside Preble’s critical habitat. The
replacement dam and portions of the construction areas would include small areas of critical habitat.
Preble’s impacts and mitigation measures will be addressed through the ESA consultation process, and
are not included in this FWMEP.
3.8.1.2 Ute Ladies’-Tresses Orchid and Colorado Butterfly Plant
Ute ladies’-tresses orchid is a federally listed threatened species. Potential habitat for Ute ladies’-tresses
orchid occurs along the North Fork and tributaries both upstream and downstream of the Halligan
Reservoir. As documented in the DEIS, no Ute ladies’-tresses orchids were detected in surveys
conducted at Halligan Reservoir from 2006 to 2008 (WEST 2017a). Additional evaluations conducted by
Jacobs in 2021 (Jacobs 2021) were concentrated within potential Ute ladies’-tresses orchid habitat
around the narrow riparian habitat below the existing dam. No Ute ladies’-tresses orchids were
observed during the 2021 survey, and habitat was determined to be marginally suitable for Ute ladies’-
EXHIBIT A TO RESOLUTION 2025-083
tresses orchid because of the presence of dense riparian grasses and dense overstory of willow and
alder.
Colorado butterfly plant (Oenothera coloradensis) was previously federally listed as a threatened
species; however, on December 5, 2019, the USFWS removed this species from the Federal List of
Endangered and Threatened Plants because of recovery (USFWS 2019). No known populations of the
Colorado butterfly plant occur within the Halligan Project Area. Therefore, this species is not further
discussed in this FWMEP.
3.8.1.3 American White Pelican
The American white pelican is a BLM sensitive species and a Tier 2 species in the State Wildlife Action
Plan (SWAP) (CPW 2015). The DEIS indicates that American white pelicans were observed on Halligan
Reservoir; therefore, the reservoir is considered potential loafing or foraging habitat for this species.
Halligan Reservoir is not within mapped American white pelican nesting areas.
3.8.1.4 Platte River Species
Because the Main Stem and North Fork are hydraulically connected to the Platte River System, ESA
Section 7 consultation with the USFWS is required to determine any adverse effects that would occur on
the five federally listed downstream species: least tern (Sterna antillarum), piping plover (Charadrius
melodus), whooping crane (Grus americana), pallid sturgeon (Scaphirhynchus albus), and western prairie
fringed orchid (Platanthera praeclara). These species are not further discussed in this FWMEP.
3.8.2 Current Conditions for State-listed Species
The DEIS evaluated reviewed state-listed species and species of concern using CPW species profiles
(CPW n.d.) and the SWAP to identify information pertaining to habitat information and distribution.
State-listed species and species of concern that could be affected by the Project are discussed in the
following sections.
3.8.2.1 Rocky Mountain Bighorn Sheep
Rocky Mountain bighorn sheep is a BLM sensitive species and is listed as a Tier 2 species in the SWAP.
Tier 2 species are defined as “species [that] remain important in light of forestalling population trends or
habitat conditions that may lead to a threatened or endangered listing status, but the urgency of such
action has been judged to be less” (CPW 2015). This species is considered a big game species; current
conditions are discussed in Section 3.7.
3.8.2.2 Northern Pocket Gopher
The northern pocket gopher is a state species of concern. The Halligan Project Area includes suitable
foothill shrubland habitat and is within the distributional range of this species.
3.8.2.3 River Otter
River otters are listed by Colorado as a threatened species. As described in the DEIS, the open water of
the North Fork and Halligan Reservoir could provide habitat for the river otter, although the known
range of the river otter ends approximately 16 miles south of the reservoir. The range of the river otter
includes the Poudre River and a small section of the North Fork, from the confluence of these rivers to
approximately 1 mile upstream of the Seaman Reservoir.
3.8.2.4 Townsend’s Big-Eared Bat
Townsend's big-eared bat is a BLM sensitive species, a state species of special concern, and is listed as a
Tier 1 species in the SWAP. The DEIS indicates that rocky outcrops and canyons downstream of the
EXHIBIT A TO RESOLUTION 2025-083
Halligan Dam along the North Fork may provide roosting habitat, and the open water of Halligan
Reservoir, scattering of sagebrush, and wetlands within the Halligan Project Area may provide
Townsend's big-eared bats with foraging habitat. This species usually forages over water, at the edge of
vegetation, and over sagebrush (Armstrong et al. 2011).
This bat species has been recorded downstream of the Halligan Dam in Phantom Canyon (Colorado
Natural Heritage Program 2015). Bat conservation has received increasing attention with the general
decline of bat populations caused by habitat loss, poisoning, and disease, including white-nose
syndrome.
Bat Survey
On July 16, 2021, Jacobs biologists conducted a bat presence/absence survey below Halligan Dam. An
auditory detection survey was completed, along with visual observation of bat feeding activity with the
riparian area from the dam to 0.5 mile downstream of the dam. The single survey was conducted over a
3-hour period beginning at dusk (7:30 p.m. to 10:30 p.m.).
Several lone bats were detected with an auditory detection device, but no large concentrations of bats
were observed. Table 3-4 summarizes the bat species detected based on audio signature, but variability
occurs within species; therefore, identification has not been confirmed.
Table 3-4. 2021 Bat Survey Results
Species Detected Number of Detections
Pallid bat (Antrozous pallidus) 1
Big brown bat (Eptesicus fuscus) 11
Red bat (Lasiurus borealis) 2
Hoary bat (Lasiurus cinereus) 1
Silver-haired bat (Lasionycteris noctivagans) 2
Western small-footed myotis (Myotis ciliolabrum) 1
Little brown bat (Myotis lucifugus) 6
Long-legged myotis (Myotis volans) 1
Unidentified detections 12
Total 37
The scattered occurrences of lone bat detections suggests that bats use the area below the existing
Halligan Dam for foraging, but the presence or absence of day or night bat roosts could not be
determined based on the limited survey.
3.8.2.5 Bald Eagles and Golden Eagles
The bald eagle is a state species of special concern and is a BLM sensitive species. The golden eagle is
listed as a Tier 1 species in the SWAP and is also a BLM sensitive species. Both bald eagles and golden
eagles are protected under the Migratory Bird Treaty Act of 1918 and the Bald and Golden Eagle
Protection Act of 1940. This prohibits the take; possession; sale; purchase; barter; offer to sell, purchase,
EXHIBIT A TO RESOLUTION 2025-083
or barter; transport; export; or import of any part, nest, or eggs of alive or dead bald or golden eagles.
State and federal recommendations outline seasonal limitations on nest encroachment or disturbance.
Bald eagles rely mainly on fish as their principal source of food during the summer months, frequently
nesting and foraging along rivers and lakes. The DEIS notes that bald eagles are known to forage in areas
of open water and were observed during field surveys of the Halligan Reservoir and the North Fork
during the summer of 2020 and 2021. No bald eagle nests or winter roost sites occur within the Halligan
Project Area, and the area is outside winter concentration, winter foraging, and winter range areas for
bald eagles identified on CPW wildlife distribution maps (CPW 2020b).
Golden eagles primarily subsist on small mammals, such as rabbits, hares, ground squirrels, and prairie
dogs. The DEIS notes that suitable golden eagle foraging habitat occurs within the entire Halligan Project
Area except for the reservoir itself, which does not provide nesting or foraging habitat. The effects are
anticipated to be temporary and are discussed in Section 3.8.4.5. Golden eagles were observed during
field surveys of the North Fork downstream of the Halligan Dam. A nest was observed by Jacobs
biologists, in summer of 2021, on a rocky vertical cliff wall approximately 0.5 mile downstream of the
North Poudre Canal Diversion structure.
Raptor Nest Survey
On July 16, 2021, Jacobs biologists conducted a nest survey within and immediately adjacent to the
inundation footprint of the enlarged reservoir and impact area for the new dam. Trees and shrubs, as
well as grassland areas within or adjacent (within 50 feet) to the proposed access road connecting the
Halligan Dam to Highway 287 were also surveyed. Additionally, nesting raptor surveys were conducted
on June 23, July 16, and July 19, 2021. Biologists used binoculars to survey the visible 0.5-mile radius
from the dam for raptor nests. No nests were located within or adjacent to the footprint of the existing
dam. The following observations were made during the nest surveys:
• A lone bald eagle was observed perched frequently and for extended periods of time on power line
poles above Halligan Dam and on rock outcroppings on the north side of the dam, but nesting
activity was not observed, and a nest location was not apparent.
• A great horned owl (Bubo virginianus) was observed on several occasions below the dam, suggesting
that an owl nest may be in Phantom Canyon below the dam.
• A red-tailed hawk (Buteo jamaicensis) nest was present near the Calloway Diversion. The nest
appeared to be maintained and is presumed to be active, but no hawks were observed on the nest.
• Two magpie (Pica nuttalli) nests were located in trees adjacent to the access road, but the nests
were not occupied at the time of the survey.
• As discussed previously, an active golden eagle nest was observed in Phantom Canyon about
0.5 mile downstream of the North Poudre Canal Diversion structure.
3.8.2.6 Northern Leopard Frog
The northern leopard frog is a Colorado species of special concern and is listed as a Tier 1 species in the
SWAP. The DEIS notes that the Halligan Project Area supports aquatic environments, such as streams
and wetlands, that would be suitable habitat for the northern leopard frog.
3.8.2.7 Common Garter Snake
The common garter snake is a species of special concern in Colorado and is listed as a Tier 2 species in
the SWAP. Common garter snakes are typically found in aquatic and riparian habitats within or adjacent
EXHIBIT A TO RESOLUTION 2025-083
to floodplains of streams and rivers. The DEIS notes that the Halligan Project Area supports aquatic
environments, such as streams and wetlands, that would be suitable habitat for the common garter
snake. Common garter snakes are typically found below 6,000 feet in elevation along the South Platte
River and its tributaries in northeastern Colorado.
3.8.3 Halligan Project Effects on Federally Listed Species
The DEIS identified 11 terrestrial species of concern that have either been documented or have suitable
habitat and ranges within the Halligan Project Area. No suitable habitat is present for black-tailed prairie
dog (Cynomys ludovicianus) or burrowing owl (Athene cunicularia); therefore, these species are not
evaluated further in this FWMEP.
Long-term direct effects on species of concern evaluated in the DEIS included habitat loss or disturbance
and effects on foraging, reproduction, and distribution from inundation and construction. Temporary
removal of vegetation associated with construction may have potential short-term effects on species of
concern until areas would be revegetated. Indirect effects on species of concern would be related to
effects on wetlands, riparian vegetation communities, and other vegetation resources along the
North Fork and Main Stem resulting from changes to water flows. Short-term indirect impacts from
construction may result from construction-related activity, noise, vibrations, lighting, and other
disturbances.
3.8.3.1 Preble’s Meadow Jumping Mouse and Habitat
Effects from the Halligan Project on Preble’s habitat are regulated through the ESA and will be
addressed through the development of a mitigation plan in coordination with the USFWS. Therefore,
Preble’s conditions, effects, and mitigation are not addressed in detail in this FWMEP. The DEIS
determined that the Halligan Project would have a major permanent adverse impact on Preble’s habitat
as a result of inundation of riparian woodlands and shrublands. Based on the Modified Proposed Action
the Project will permanently displace 5.26 acres of Preble’s habitat around the existing reservoir edge
and downstream of the existing dam within the footprint of the proposed dam. A Preble’s habitat
functional assessment, approved by the USFWS, found that the permanent effects equate to the loss of
4.04 functional units of habitat (much of the reservoir edge habitat has low habitat functional for
Preble’s). Temporary impacts on Preble’s habitat (related to construction access) are estimated to be
0.47 acres (0.36 functional unit). Fort Collins has worked proactively to preserve habitat on the Roberts
Ranch Conservation Area and has worked closely with the Preble’s Species Conservation Team in the
effort to establish a Preble’s recovery population in the North Fork watershed. Many of the Halligan
Project beneficial effects, mitigation, and enhancements described in this FWMEP would benefit
Preble’s habitat through increased stream flow and likely improved riparian conditions.
3.8.3.2 Ute Ladies’-tresses Orchid
The Halligan Project has the potential to impact wetland and riparian habitat that may be considered
suitable for the Ute ladies’-tresses orchid. In the DEIS, the Corps determined that the Halligan Project
would have no effect on the Ute ladies’-tresses orchid because no known occurrences of this plant were
identified within the study area. Ute ladies’-tresses orchid conditions, effects, and mitigation are not
addressed in detail in this FWMEP. However, many of the beneficial effects, mitigation, and
enhancements described in this FWMEP could benefit Ute ladies’-tresses orchid habitat through
increased stream flow and improved riparian conditions.
3.8.3.3 American White Pelican
American white pelicans were observed on Halligan Reservoir; therefore, the reservoir is considered
potential loafing or foraging habitat for the American white pelican. Because loafing or foraging habitat
EXHIBIT A TO RESOLUTION 2025-083
would be expanded through reservoir enlargement, the Halligan Project would result in a minor benefit
for the American white pelican, as described in the DEIS.
3.8.3.4 Platte River Species
The CMP (City of Fort Collins 2019c), prepared as part of the DEIS, documented that effects on the five
federally listed downstream Platte River species are expected to be unperceivable, and that the Halligan
Project is not expected to result in any discernable changes to stream flow in the South Platte River.
Fort Collins participates in the SPWRAP, which outlines a programmatic approach to Section 7
consultation with the USFWS. Currently, mitigation is not expected to be needed for South Platte River
depletions. If mitigation measures are identified during this programmatic approach or from USFWS
consultation, they will be incorporated into the mitigation strategy for the Halligan Project.
3.8.4 Halligan Project Effects on State-listed Species
3.8.4.1 Rocky Mountain Bighorn Sheep
Halligan Project impacts on bighorn sheep are discussed in detail in Section 3.7.
3.8.4.2 Northern Pocket Gopher
Although northern pocket gophers have not been documented within the study area, the DEIS indicated
that the Halligan Project would result in a minor effect on the northern pocket gopher as a result of
inundation of foothill shrublands suitable habitat. These effects would be discountable and insignificant
because they would not have a noticeable effect on populations within the surrounding area because
other suitable habitat is available. Temporary impacts anticipated are limited to temporary construction
access and staging areas that will be reclaimed upon completion of the Project.
3.8.4.3 River Otter
Because the known range and sightings of the river otter do not overlap with the inundation areas of the
Halligan Project, the DEIS Section 4.13.2.6 states that expanding the reservoir would not adversely
impact this species. The DEIS Section 4.13.3.6 also states that a potential minor indirect benefit to river
otters could result from the Halligan Project. More specifically, increased stream flows to the North Fork
from the Winter Release Plan and the Summer Low-flow Plan could improve the fishery health and, in
turn, would provide a larger, more stable food source for river otters. Because there is no documented
occurrence of river otter in the section of the North Fork below Halligan Dam where construction would
occur, nor in or near the inundation upstream (0.75 mile section) above the enlarged reservoir, no
temporary impacts are anticipated.
3.8.4.4 Townsend’s Big-eared Bat
The DEIS determined that roost habitat would not be directly affected by the Halligan Project, but
construction noise and vibration associated with the Halligan Project may cause temporary disturbance
effects on Townsend’s big-eared bats using nearby roost habitat. Furthermore, overall effects to
foraging habitat would be discountable and insignificant, and the Halligan Project would have a minor
impact on Townsend’s big-eared bat. Year-round winter and summer minimum stream flows
(Section 3.3.2) provided by operations of the enlarged reservoir would enhance riparian foraging habitat
below Halligan Reservoir for Townsend’s big-eared bats.
3.8.4.5 Bald Eagles and Golden Eagles
The DEIS determined that the Halligan Project would not likely cause permanent direct effects on bald
eagles. Although some foraging sites around Halligan Reservoir may be altered as a result of inundation,
the expanded surface area of the enlarged reservoir would create new foraging areas, creating a minor
EXHIBIT A TO RESOLUTION 2025-083
beneficial effect on bald eagles. Because there are no active nesting pairs, roost sites, or suitable winter
habitat temporary impacts associated with construction activities such as noise, nighttime lighting,
blasting, and potential batch plant operation impacts on foraging activities are anticipated to be minor
(temporary avoidance) and short term in duration. Bald eagle use of the area is expected to return to
preconstruction levels shortly after construction is completed. Increased reservoir surface area will
provide increased foraging opportunity for bald eagles in the long term.
For golden eagles, expansion of Halligan Reservoir would reduce habitat for their prey base in
inundation and construction areas. However, in the DEIS, impacts were considered discountable and
insignificant because golden eagles are wide-ranging, and vast areas of open foothills shrubland and
grassland for foraging would remain after reservoir expansion. Long-term direct effects on golden eagles
would be minor. Temporary impacts associated with construction activities such as noise, nighttime
lighting, blasting, and potential batch plant operation impacts on foraging activities are anticipated to be
minor (temporary avoidance) and short term in duration. Golden eagle use of the area is expected to
return to preconstruction levels following completion of replacement dam construction. Revegetation of
temporary construction disturbance areas, and regrowth of a reservoir edge riparian community is
anticipated to be completed within approximately 5 to 7 years.
3.8.4.6 Northern Leopard Frog
The Halligan Project supports aquatic environments, such as streams and wetlands, that could be
suitable habitat for the northern leopard frog. However, northern leopard frog has not been observed
around the reservoir and it is unlikely that leopard frog inhabits the reservoir edge wetlands given the
inconsistent and fluctuating water levels, lack of emergent wetland vegetation (narrow reservoir edge
wetlands are dominated by willow and cottonwood canopy), and general lack of suitable breeding
habitat; steep rocky reservoir banks offer very little refuge or dispersal area for the leopard frog as
water levels draw down in mid-summer and reservoir becomes disconnected from the minimal and
narrow bands of emergent wetland vegetation that does exist around the reservoir. The DEIS indicates
an overall minor beneficial effect from the Halligan Project on northern leopard frog habitat. The DEIS
Section 4.12.3.11 indicates that some suitable habitat would be adversely affected because
approximately 16.74 acres of wetlands would be inundated from the enlarged reservoir. New, similar
habitat could be created at the new enlarged reservoir edge after soils and vegetation acclimate to the
new hydrology. This process of reservoir edge riparian community re-establishment is anticipated to
occur over approximately 5 to 7 years but may take longer if drought conditions persist after Project
completion. Enlarging Halligan Reservoir would permanently displace riverine habitat on the
downstream side of the existing dam, but because of the high energy associated with the current dam
operations spillway and significant disturbance existing in this tight rocky canyon, the area immediately
below the existing dam is not considered suitable for northern leopard frog.
Year-round winter and summer stream flows (Section 3.3.2) provided by operation of the enlarged
reservoir would enhance habitat for the northern leopard frog in Phantom Canyon and the Livermore
Valley. Lastly, the Halligan Project would compensate for the loss of any wetland habitat (to be
determined through the Section 404 permitting process and not discussed in this FWMEP), which would
also benefit the northern leopard frog by replacing poor reservoir edge habitat with wetlands that
would provide equal or potentially greater northern leopard frog habitat function.
As noted in Section 4.12.2.1.5 of the DEIS, some mortality of reptiles and amphibian adults, juveniles,
eggs, tadpoles, and larvae might occur during construction, but this would not likely result in a long-term
decline of amphibians at Halligan Reservoir or along the North Fork. The removal of vegetation for
construction, both long- and short-term, would potentially remove cover and foraging resources for
EXHIBIT A TO RESOLUTION 2025-083
some reptiles and amphibians. Still other reptiles and amphibians might be killed or displaced as a result
of construction activities. The Halligan Project might locally reduce species abundance during
construction; however, it would not likely lead to large-scale species loss or require species protection
due to habitat loss. Halligan Dam rehabilitation would have a negligible to minor effect on amphibians
and reptiles.
3.8.4.7 Common Garter Snake
Typically, common garter snakes are found in aquatic and riparian habitats within or adjacent to
floodplains or streams and rivers that occur below 6,000 feet in elevation (CPW n.d.). The DEIS indicates
that the Halligan Project would affect suitable habitat for the common garter snake, and downstream
segments of the North Fork are within the range of the common garter snake. However, because the
reservoir is located approximately 6,300 feet in elevation, above the known range limit, the Halligan
Project would not have negative effects on the common garter snake around the reservoir
(Pioneer 2017a).
As described for other species, year-round winter and summer minimum stream flows (Section 3.3.2)
provided by operation of the enlarged reservoir would enhance habitat for garter snakes on the
North Fork. Therefore, the Halligan Project is expected to result in an overall benefit to the species, and
species-specific mitigation measures are not proposed in this FWMEP.
3.9 Recreation
3.9.1 Current Conditions
Recreational use on Halligan Reservoir has historically been, and currently is, restricted to owners and
guests of the Landowners Association for Phantom Canyon Ranches (LAPCR). Some public use may have
occurred on portions of Halligan Reservoir that were thought to be in the Middle Unit of the Cherokee
SWA. Since 1988, the LAPCR has had recreational and agricultural use rights to the surface of Halligan
Reservoir and what is currently City-owned land in and around Halligan Reservoir, through lease
agreements with NPIC and later Fort Collins. The current lease provides LAPCR with recreational use of
the surface of Halligan Reservoir and recreational and agricultural use of City-owned land in and around
Halligan Reservoir until construction of the Halligan Project concludes.
Other areas around Halligan Reservoir that provide recreational activity include the Cherokee SWA
located west of the reservoir, which is used primarily for hunting and fishing, and the North Fork
downstream of the reservoir, which is used for fishing by private property owners and guests of The
Nature Conservancy’s Phantom Canyon Ranch. Although a parking area near the inlet of Halligan
Reservoir is accessible through the SWA, the surface of the Halligan Reservoir and Fort Collins-owned
land in and around the reservoir is not open to public access.
3.9.1.1 Land Ownership
Land ownership and access around Halligan Reservoir and at potential mitigation sites is a key factor in
Halligan Project activities, including ecological monitoring and mitigation. As part of Fort Collins’ due
diligence related to planned acquisition of property rights to build and operate the enlarged Halligan
Reservoir, Fort Collins conducted detailed research on land ownership in and around Halligan Reservoir.
This research identified isolated parcels in Section 29 and northeast ¼ of Section 32 that were thought
to be held in fee title by CPW but were determined to be held in fee by a private entity or Fort Collins
(Figure 3-4). The parcels total approximately 39 acres. Upper portions of the enlarged Halligan Reservoir
would be located on portions of these lands, which are, for the most part, surrounded by the Cherokee
SWA–Middle Unit. It was also determined that the parking area near the west side of Halligan Reservoir
EXHIBIT A TO RESOLUTION 2025-083
in the northeast ¼ of Section 32 is located on property held in fee by Fort Collins. To Fort Collins’
knowledge, there is no agreement or easement in place that provides public access to the private
entity’s or this portion of Fort Collins’ land.
Figure 3-4. Sections 29 and 32 on the Western Edge of Halligan Reservoir
EXHIBIT A TO RESOLUTION 2025-083
3.9.2 Halligan Project Effects on Recreation and Public Access
The DEIS Section 4.16.4.2 indicates that, overall, the Halligan Project would result in a mostly negligible
effect on long-term land- and water-based recreational activity and related economic activity, although
site-specific beneficial and adverse effects would occur.
The enlarged Halligan Reservoir would inundate an approximately 0.75-mile reach of the North Fork
upstream of the existing Halligan Reservoir, resulting in the loss of approximately 20 acres of potential
hunting lands and river fishing along a 0.4-mile stretch of this reach.
Most of the primary inundation area along the North Fork in Sections 29 and 32, T11N, R70W, was
historically believed by CPW to be in the Cherokee SWA since the acquisition of the land in the
late 1960s/early 1970s. According to CPW the public has accessed this part of the inundation area for
over 50 years10. Fort Collins staff was performing its due diligence in researching land ownership all
around Halligan Reservoir and identified discrepancies in various deeds, including those in Sections 29
and 32. Following thorough title research of the inundation area, recorded title to the inundation area in
these sections is privately owned or owned by Fort Collins. Additionally, the parking area near the west
side of Halligan Reservoir in the northeast ¼ of Section 32 located on Fort Collins’ property is within this
primary area to be inundated by the enlarged Halligan Reservoir. None of the lands privately owned or
owned by Fort Collins are authorized for public hunting or fishing. No publicly owned lands for
authorized public hunting or fishing recreation will thus be technically impacted by the Project.
However, public access could be affected until the access issues are resolved, as described in
Section 4.3.7.1.
In addition to the primary inundation created by the ordinary high water mark of the enlarged Halligan
Reservoir, Fort Collins is required by DWR (refer to Rule 7.9.3.3 in 2 CCR 402-1, Division of Water
Resources Rules and Regulations for Dam Safety and Construction) to acquire fee ownership or an
easement for lands that would be inundated by the modeled inflow design flood surcharge, which will
include lands in Sections 29 and 32 that are part of the Cherokee SWA owned by CPW. Since the private
entity or Fort Collins owns the land about 14 feet above the ordinary high water mark of the enlarged
Halligan Reservoir, the only floods that will be above the private entity or Fort Collins’ lands would have
a recurrence interval of 1 in 100,000 (0.001%) and the maximum probable flood has a recurrence
interval of 1 in 10,000,000 (0.00001%). Although this highly infrequent inundation will not be
permanent, public use of these lands would be impacted while these lands are inundated, and until they
are reclaimed following any flooding event, if necessary. It is estimated that approximately 21 acres of
land owned by CPW would be inundated during the probable maximum flood for which Fort Collins
would need a flood easement from CPW.
Because the surface of Halligan Reservoir is not open to the public for recreational use, construction of
the Halligan Project would not impact public recreation on the reservoir. The LAPCR’s private access to
Halligan Reservoir (refer to Section 3.9.1) would be minimally impacted during construction and would
be limited to specific times when the reservoir level would be drawn down near the end of construction
for partial or total demolition of the existing dam. LAPCR currently would have no rights to access the
surface of the enlarged reservoir following completion of construction. Fort Collins has no current plans
to allow recreation on the surface of Halligan Reservoir following construction. If, in the future, surface
water recreation is considered at the enlarged Halligan Reservoir, Fort Collins agrees to consult with
10 Fort Collins is evaluating if and the extent to which the public has accessed this part of the inundation area and makes no representations on this issue.
EXHIBIT A TO RESOLUTION 2025-083
CPW. A safety buffer on the water out to approximately 300 feet upstream of the existing dam would
likely be implemented during the construction period.
Wildlife watching, hiking, horseback riding, and other land-based activities occur on properties
surrounding Halligan Reservoir. Construction activity, including noise and dust generation and increased
traffic volumes (construction workers and trucks), may temporarily affect the quality of these
experiences. However, construction activities would predominantly be confined to the area near the
existing dam site, which is not within residential view.
3.9.3 Evaluation of Future Public Use of the Enlarged Halligan Reservoir
Fort Collins and CPW held multiple meetings to discuss the possibility of allowing public recreation on
the enlarged Halligan Reservoir and some of the surrounding City owned land. From approximately 2016
through 2019, CPW and Fort Collins discussed various recreation concepts that included opening all or
portions of Halligan Reservoir to public recreation after enlargement. The recreation concept included in
the DEIS included reservoir access through the Cherokee SWA, whereby shoreline and surface water
fishing opportunities with human-propelled watercraft would be available at the enlarged Halligan
Reservoir to those with a valid hunting or fishing license, or SWA pass. The only public recreation access
would be through the Cherokee SWA so this recreation concept anticipated the reservoir operating as a
part of the administrative boundaries of the Cherokee SWA and would be consistent with the existing
regulations of the SWA.
To further evaluate the costs, benefits, and impacts of opening the enlarged Halligan Reservoir to public
recreation, Fort Collins staff members, in conjunction with CPW staff input, used a framework adopted
by Fort Collins’ Natural Areas Department (Interagency Visitor Use Management Council 2016) to
evaluate the impacts and benefits of recreation at and around the enlarged Halligan Reservoir. The
study focused on the following topics:
• Ecological impacts
• Cultural resource impacts
• Social considerations
• Administrative considerations
At the conclusion of the analysis, Fort Collins staff members recommended that public recreation at the
enlarged Halligan Reservoir not be pursued, even in a limited nature, predominantly because of
ecological impacts that Fort Collins staff members anticipated based on DEIS analyses and their own
professional experiences. Other elements that factored into the decision included the cost of providing
safe recreational opportunities to this area, and the relatively narrow range of recreationalists who
would benefit from the opportunity.11
Fort Collins understands CPW’s desire to see public angling access at the enlarged Halligan Reservoir.
Since the Halligan Project is not impacting surface water recreation at Halligan Reservoir, Fort Collins
and CPW have agreed to continue discussions related to recreational opportunities at the enlarged
Halligan Reservoir in a process separate from the current processes to enlarge Halligan Reservoir and
the FWMEP. To formalize this commitment, Fort Collins will include language in an intergovernmental
agreement with CPW to continue discussions related to recreation at the enlarged Halligan Reservoir.
Those discussions may include the reservoir being managed for recreation by CPW as a part of the
Cherokee SWA.
11 Access for public recreation at an enlarged Halligan Reservoir would be provided through Cherokee SWA, which requires a valid hunting,
fishing, or recreational day use license to enter, as well as a high-clearance four-wheel drive vehicle. These access limitations do not fully align
with Fort Collins’ focus on equity and affordability to provide equal opportunities for its citizens.
EXHIBIT A TO RESOLUTION 2025-083
4 Proposed Fish and Wildlife Mitigation Plan
This chapter constitutes the proposed mitigation plan for anticipated Halligan Project impacts on fish
and wildlife resources. The impacts are summarized in Section 3 and described in greater detail in the
DEIS and associated technical reports.12 Avoidance, minimization, and compensatory mitigation
measures have been developed to address fish and wildlife impacts identified in the DEIS, as well as
other concerns identified by CPW staff specific to impacts on fish and wildlife resources.
The DEIS (Corps 2019) presented a draft CMP prepared by Fort Collins (City of Fort Collins 2019c) that
includes both mitigation and enhancement measures. Based upon public comments received on the
DEIS, comments from Project stakeholders, and discussions with CPW staff, this FWMEP builds upon
and/or replaces many of the aquatic life and terrestrial wildlife components of the draft CMP. All
measures included in this FWMEP are also summarized in the table contained in Appendix B. Mitigation
areas are mapped in Appendix A. An updated final CMP will be prepared by Fort Collins for the Final EIS.
4.1 Mitigation Approach
Fort Collins has developed an approach to mitigation that will not only serve to satisfy regulatory
requirements for protection of fish and wildlife, but also seeks to improve existing social13 and ecological
conditions for the people and natural systems of the Poudre River watershed. This approach also applies
to enhancement measures described in Section 5.
Fort Collins’ mitigation objectives for the Halligan Project have been developed to comply with
applicable regulatory requirements while acknowledging the importance of the Poudre River watershed
to the Fort Collins community, as detailed in the 2020 Strategic Plan (City of Fort Collins 2020a) and as
follows:
• Avoid and minimize Halligan Project impacts on natural systems, to preserve ecological integrity
• Compensate for unavoidable Halligan Project impacts through mitigation measures that restore or
replace locally important resources and function
• Improve ecological function of the North Fork system as a whole
Considering these mitigation objectives, and recognizing the important and localized ecological
functions of the impacted resources, Fort Collins developed the following guidelines to identify and
prioritize potential mitigation opportunities incorporated into this FWMEP:
• Account for the inherent benefits from the Halligan Project, including those anticipated to result
from flow-related operational measures and the natural re-establishment of wetland and riparian
communities at the enlarged reservoir shoreline and on the North Fork.
• Prioritize mitigation opportunities located near Halligan Reservoir and the North Fork to enhance or
replace the natural functions in the same watershed and stream system, maintaining locally
significant resources and ecological functions.
• Prioritize mitigation concepts that involve working with local partners.
12 This FWMEP does not alter in any way the DEIS and associated technical reports and their descriptions of the Halligan Project’s effects. To the
extent that there are inconsistencies between the Halligan Project’s effects as described in this FWMEP and the DEIS, any such inconsistencies
will not be interpreted to reduce the mitigation Fort Collins intends to complete for the Halligan Project.
13 Refer to the Shared Vision Planning process in Section 2.4.1 regarding social conditions.
EXHIBIT A TO RESOLUTION 2025-083
•Prioritize mitigation concepts that benefit whole systems or multiple resources.
•Identify and target local resources known to be in a degraded condition that can be improved to
increase function and ecological benefit.
Fort Collins developed the mitigation measures presented in this FWMEP based on the mitigation
objectives and guidelines to benefit numerous environmental components. Based on all of Fort Collins’
work on the Halligan Project over the years, it is Fort Collins’ position that this overall mitigation
approach considers the entire ecological system, where the functional benefits of the mitigation actions
taken together are greater than the sum of the Halligan Project’s impacts on those individual parts. As
an example, the Winter Release Plan and Summer Low-flow Plan will work together to essentially
eliminate dry-up points along the North Fork and improve existing stream hydrology. These
improvements would benefit not only the aquatic ecosystem, including fish and macroinvertebrates, but
also the hyporheic zone hydrology of the stream. The resulting greater hydrologic connectivity would
likely support the function of surrounding wetlands and riparian vegetation, which, in turn, would
benefit wildlife that depend on healthy riparian environments.
This section provides a mitigation strategy for each affected fish and wildlife resource. In many
instances, several mitigation strategies address one resource but likely have a ripple effect benefiting
other resources. The mitigation and enhancement approach summarized in Sections 4 and 5,
respectively, has been developed over decades, based on regulatory requirements, input from Project
stakeholders, regional partners, environmental groups, and in coordination with CPW staff members.
4.1.1 Regulatory Mitigation Categories
Mitigation described in this FWMEP falls into one of the following three regulatory mitigation categories
(defined in the Key Terminology section): avoidance, minimization, and compensatory mitigation.
Additionally, Fort Collins has developed enhancement measures that go above and beyond mitigation
requirements and demonstrate Fort Collins’ commitment to improving existing environmental
conditions. Enhancement measures are described in Section 5.
Avoidance and minimization measures have been, and will continue to be, implemented during all
Halligan Project stages, including planning and design, construction, and operations. Avoidance and
minimization measures are described in Section 4.2. Compensatory mitigation measures will generally
begin before or concurrently with the correlating impacts. Compensatory mitigation measures are
described in Section 4.3. Early compensatory mitigation was completed through preservation of habitat
at Roberts Ranch, as described in Section 4.3.1.
4.1.2 Changes from DEIS Conceptual Mitigation Plan
This FWMEP builds upon, updates, and/or replaces many of the aquatic life, terrestrial wildlife, and
recreational components of the draft CMP presented in the DEIS (City of Fort Collins 2019c).
In response to comments on the CMP, Fort Collins has provided the following additional information in
this FWMEP, or has finalized decisions about items that were not final when the CMP was issued:
•Specific details about how the flow-related operational measures will be implemented, including
when they could be curtailed (refer to Section 4.2.1)
•Fort Collins’ commitment to attempt to protect their releases from the enlarged portion of Halligan
Reservoir to prevent that water from being diverted by exchange or otherwise (refer to
Section 4.2.1)
EXHIBIT A TO RESOLUTION 2025-083
• Recreation will not be pursued at the enlarged Halligan Reservoir as part of the Halligan Project at
this time because of the reasons described in Sections 3.9.2 and 3.9.3
• Baseline monitoring of environmental conditions (water quality, temperature, riparian habitat,
raptors and bats) was augmented in 2020 and 2021
• Conceptual sediment management measures have been developed to manage sediment both
during construction and long-term operations
• A summary of preliminary best management practices (BMPs; that is, control measures) has been
developed to manage and control stormwater and pollutants (refer to Section 4.2.3.7)
• Stream restoration on the North Fork as an enhancement for aquatic resources (refer to
Section 5.1.1)
• Updated measures to mitigate anticipated water quality or temperature effects, or to enhance
existing conditions
• Removal of alphanumeric codes: the CMP used a unique system of abbreviations to reference
specific mitigation measures (for example, “SF1” for stream flow measure 1, the Winter Release
Plan); this FWMEP uses descriptive names for each measure rather than abbreviations
The following mitigation measures, originally detailed in the draft CMP, are no longer viable based on
new information obtained during Project development and design, and are no longer proposed as
mitigation or enhancement measures:
Greenback Cutthroat Trout Reclamation and Diversion Structures Modification for Reintroduction—In
the draft CMP, Fort Collins proposed the option of stocking an experimental population of native pure-
strain greenback cutthroat trout to the 6-mile segment of the North Fork between Halligan Dam and the
North Poudre Canal Diversion. Along with the proposed restocking effort, Fort Collins proposed creation
of fish barriers at the North Poudre Canal and Calloway Diversions to maintain a genetically pure and
isolated greenback cutthroat trout population. However, further analysis of temperature data, and a
feasibility assessment by Fort Collins, in consultation with CPW staff, related to costs and sustainability
associated with screening the outlet works and spillway, have determined the proposed Greenback
reintroduction concept to be cost prohibitive and ultimately unsustainable in the long term. Fort Collins
is, therefore, proposing to proceed with Option A described in the draft CMP: reconnecting larger
habitat segments of the North Fork by providing fish passage around the North Poudre Canal Diversion
and removing or modifying the Calloway Diversion to improve fish passage. This improved river
connectivity will benefit a wide range of riverine aquatic species, with a primary focus on small-bodied
native species.
Revegetation of Existing Tailings and Spoil Piles and Previously Disturbed Areas—In the draft CMP,
Fort Collins proposed revegetating spoil piles left in place near the existing Halligan Dam as a result of
construction of the dam in 1909. However, the Halligan Project now includes constructing a replacement
dam downstream of the existing dam, which would result in inundation of the spoil piles and would
eliminate the benefits of this previously proposed measure.
Fish population and aquatic habitat surveys—In the draft CMP, Fort Collins proposed working with CPW
to conduct additional population surveys and field surveys of the amount and quality of available
physical habitat for fish species in representative reaches of the North Fork between Halligan Dam and
Seaman Reservoir. Following the draft CMP, Fort Collins evaluated existing aquatic habitat conditions in
the North Fork (GEI 2019a, 2019b), and CPW has historic and recent fish population data as described in
Section 3.5.1 of this FWMEP.
EXHIBIT A TO RESOLUTION 2025-083
4.2 Avoidance and Minimization
Fort Collins has incorporated many elements into the Halligan Project to avoid and minimize
environmental impacts. The Halligan Project is the culmination of decades of planning and balances Fort
Collins’ water supply needs with opportunities to minimize environmental impacts and improve existing
conditions on the North Fork below Halligan Reservoir.
Appendix B provides a summary of each mitigation or enhancement measure and each measure’s
primary focus and secondary benefits.
4.2.1 Flow-related Operational Measures
Several flow-related operational measures will be included with the Halligan Project to collectively avoid
and minimize impacts on stream functions while also improving certain stream functions that are
currently degraded. These flow-related operational measures will re-establish perennial flow of 3 cfs to
5 cfs or more to the North Fork below the enlarged Halligan Reservoir, minimize abrupt changes to flows
from the enlarged reservoir operations, and allow for peak flows to bypass the enlarged reservoir when
Fort Collins could otherwise be diverting water to storage. The proposed flow-related operational
measures include the following:
•Winter Release Plan
•Summer Low-flow Plan
•Ramping Rate Limitations
•Peak Flow Bypass Program
•End of Summer Flushing Event
The combined environmental benefits provided by these flow-related operational measures to the
North Fork below the enlarged Halligan Reservoir are described in more detail in Section 4.2.1. These
flow-related operational measures would have varying beneficial effects on the approximately 22 miles
of the North Fork from the replacement Halligan Dam to Seaman Reservoir. They would result in
moderate seasonal beneficial effects on aquatic resources from Halligan Reservoir downstream to the
North Poudre Canal return structure (approximately 8 miles) on the North Fork (DEIS Section 4.8.3.4.1.2)
with major beneficial effects from the North Poudre Canal return flow down to Rabbit Creek
(approximately 2 miles; DEIS Section 4.8.3.4.1.3), and minor benefits extending from Rabbit Creek down
to Seaman Reservoir (approximately 12 miles; DEIS Section 4.8.3.4.1.2). The Halligan Project would
increase stream flows in winter and other traditionally low-flow periods, improve river connectivity
during low-flow periods, and increase downstream areas of riffle and pool complexes (DEIS
Section 4.8.3.4.1.3). The enlarged reservoir operations would eliminate almost all14 zero-flow days at
frequent dry-up points and minimize extreme flow fluctuations from Fort Collins’ use of the
enlargement. Therefore, compensatory mitigation is not proposed for offsetting impacts on stream
functions or stream flow because the Halligan Project’s predicted impacts on stream functions and
stream flow are sufficiently avoided and minimized through the operational measures. Nevertheless, in
addition to the flow-related operational measures described in Section 4.2.1, Fort Collins has also
committed to additional enhancement measures to improve current stream function and stream flow,
which are described in Section 5.1.
To further benefit aquatic and other wildlife, circumstances may exist when, in consultation with CPW,
Fort Collins will deviate slightly from the planned flow-related operational measures. Such modifications
14 See potential exceptions at end of this Section 4.2.1.1 Winter Release Plan “Curtailment of the Winter Release Plan” and Section 4.2.1.2 Summer Low-
flow Plan “Curtailment of the Summer Low-flow Plan.”
EXHIBIT A TO RESOLUTION 2025-083
of timing, duration, and quantity of flow could occur, provided that any such modifications do not affect
Fort Collins’ storage and yield from the enlarged Halligan Reservoir and are consistent with all applicable
permits and approvals, agreements, and decrees. This flexibility is needed to periodically modify flows, if
necessary and when conditions are favorable, for the potential benefit of aquatic wildlife, as suggested
by CPW. For example, per CPW’s request, in certain years Fort Collins may change the period of the
Summer Release Plan such that flows are decreased in October to help manage brown trout.
In addition to the operational flow measures mentioned in this section, Fort Collins will consider ways to
make releases that complement a natural hydrograph to reduce potential effects to the river system for
other releases it makes from its portion of the enlarged Halligan Reservoir. For example, during a severe
drought, Fort Collins will try to avoid short duration, large releases in the fall, in favor of longer, lower-
duration releases, to avoid or reduce impacts to fish below Halligan Reservoir. Large fall releases are
unlikely to occur since Fort Collins’ water demands are lower in the fall and there will likely be other
water rights that can be taken that reduce the need for Halligan releases. Also, Fort Collins does not
have other significant storage capacity below Halligan Reservoir to which its releases could be moved. If,
in the future, Fort Collins needs to make a large release, Fort Collins may notify CPW in advance to
consider ways to make releases that avoid or minimize impacts to aquatic life.
4.2.1.1 Winter Release Plan
As part of Halligan Project operations, Fort Collins will provide continuous releases of 3 cfs from its
water stored in the enlarged Halligan Reservoir to the North Fork from October 1 through April 30 each
year. Fort Collins will implement the Winter Release Plan the first winter after the new Halligan Dam has
been approved to store water by the DWR and Fort Collins’ portion of the enlarged reservoir has at least
3,000 acre-feet of water. This Winter Release Plan will be a means for Fort Collins to meet wintertime
return flow obligations while providing a concurrent benefit to the aquatic environment. Based on
analyses during the permitting process (GEI, 2016, 2018; Miller, 2017; WEST, 2017a, 2017b; City of Fort
Collins, 2017; Pioneer, 2016a, 2016b, 2017b), it is projected that the Winter Release Plan will provide
the following benefits:
• Eliminate almost all15 zero-flow days on the North Fork (in combination with the Summer Low-flow
Plan [Section 4.2.1.2]).
• Result in beneficial effects on the North Fork for small-bodied native fish, in the form of a
continuous, more longitudinally connected aquatic corridor compared to the existing zero-flow
conditions.
15 See potential exceptions at end of this section “Curtailment of the Winter Release Plan.”
EXHIBIT A TO RESOLUTION 2025-083
•Create additional wetted channel area that will benefit small-bodied native fish, trout, and
macroinvertebrates (these benefits vary along the North Fork, with benefits expected to be greatest
in the Phantom Canyon below the North Poudre Canal
Diversion structure).
•Re-establish basic habitat requirements for aquatic
species through the reintroduction of perennial flow.
The Winter Release Plan includes reconstructing the North
Poudre Canal Diversion similar to its current configuration,
but to allow the bypass of Fort Collins’ releases from the
enlarged Halligan Reservoir so that the water remains in the
North Fork. Currently, the North Poudre Canal Diversion
does not allow for such flow bypasses.
The Winter Release Plan will also result in benefits that will
offset the impact resulting from the inundation of
approximately 0.75 mile of the CWCB’s instream flow water
right (Water Court Case 1985CW430) on the North Fork
above Halligan Reservoir (as discussed further in this
section).
Figure 4-1 shows a zero-flow condition that is common in
Phantom Canyon below the North Poudre Canal Diversion
under current operations of the existing reservoir. This flow
condition will be significantly improved by implementing the Winter Release Plan.
Operation of the Winter Release Plan
Fort Collins will release a minimum of 3 cfs from its share of water stored in the enlarged Halligan
Reservoir from October 1 through April 30 every year (winter releases). Instrumentation will be installed
at the dam and at or near the reconstructed North Poudre Canal Diversion to monitor the winter
releases bypass of the North Poudre Canal Diversion. The Winter Release Plan will not prevent Fort
Collins from releasing more than 3 cfs during this time period as may be needed to meet demands or for
other operational, mitigation, or enhancement needs. However, such additional releases are not
planned. Additional releases will be subject to ramping rates as discussed in Section 4.2.1.2.
The winter releases will be delivered down the North Fork to its confluence with the Main Stem and
either “exchanged up” to the Fort Collins Intake(s) on the Main Stem or delivered downstream for other
purposes. If the winter releases are exchanged, Fort Collins will divert a like amount of water at one of
the Fort Collins’ Intakes. The amount of water diverted at Fort Collins’ Intake(s) will be the amount
released from the enlarged Halligan Reservoir reduced by the administrative transit loss assessed by
DWR. In certain rare conditions when inadequate flows exist in the Main Stem for Fort Collins to
perform an exchange to its intake(s), Fort Collins may find an entity willing to accept the winter releases
in exchange for transferring other water to Fort Collins. These trades will require an agreement between
Fort Collins and the other entity, and such an agreement will be reached in the future.
Greeley may potentially divert and store the winter releases in Seaman Reservoir using its own exchange
water rights. In these situations, Greeley would divert and store the winter releases and deliver a like
amount of water to the Main Stem at some point above the downstream calling water right.
Figure 4-1. North Fork, Zero-Flow in
Phantom Canyon, May 2002
Source: Miller 2017
EXHIBIT A TO RESOLUTION 2025-083
CPW has expressed concerns about anchor ice forming in the Exchange Reach between Fort Collins’
intakes and the confluence of the North Fork and Main Stem. Fort Collins operational staff has not
experienced or heard of past instances of anchor ice forming in the lower part of the Poudre River
canyon, because most icing issues occur in the upper reaches of the river. If the formation of anchor ice
occurs in the Exchange Reach in the future during times when Halligan exchanges are made, Fort Collins
agrees to consult with CPW to consider ways to avoid the issue such as, but not limited to, temporary
curtailment of making those exchanges.
Protection of the Winter Releases
NPIC cannot divert the winter releases into the North Poudre Canal pursuant to an existing agreement
with Fort Collins. Additionally, Fort Collins will attempt to protect the winter releases from Halligan Dam
to Seaman Reservoir using the “Protected Mitigation Release” statute (CRS Section 37-92-102[8]). To
acquire protection for these releases under this protection mechanism, Fort Collins will need to both
reach an agreement with the CWCB and acquire a decree from the Water Court. Fort Collins will
undertake a good faith effort to protect the winter releases under the Protected Mitigation Release
statute; however, success is not guaranteed because it will depend on factors outside of Fort Collins’
control.
Per the statute, the protected mitigation releases will need “to reasonably avoid, minimize, or mitigate
the impacts of the new reservoir capacity on fish and wildlife resources within the qualifying stream
reach in accordance with a fish and wildlife mitigation plan.” Fort Collins will need to redivert and use
the protected mitigation releases after they flow through the protected “qualifying stream reach.”
Because the protection of the winter releases (and release from the Summer Low-flow Plan as discussed
below in Section 4.2.1.2) under the Protected Mitigation Release statute relies on other entities’ and the
Water Court’s discretion beyond Fort Collins’ control, Fort Collins cannot guarantee a particular result. If
Fort Collins does not successfully acquire a Water Court decree to protect the winter and summer
releases, the releases will not be protected from diversion under approved augmentation plans,
substitutions, and exchanges, similar to Greeley’s potential diversion of the winter releases into the
Seaman Reservoir as previously discussed. However, such diversions of the winter and summer releases
will be unlikely for several reasons, including (1) they cannot be diverted into the North Poudre Canal
pursuant to Fort Collins’ agreement with NPIC, (2) there are no other substantial diversion locations on
the North Fork above Seaman Reservoir, (3) the entire area is very remote and difficult to access to
divert water and to convey water that has been diverted, (4) there are numerous conservation
easements in the area that make development difficult, and (5) there are few sources of augmentation
and replacement water on the Main Stem and North Fork above the Phantom Canyon mouth. If
Fort Collins fails to acquire a Water Court decree to protect Halligan Releases under the Protected
Mitigation Release statute, or its agreement with NPIC changes such that Halligan Releases can be
diverted into the North Poudre Canal, Fort Collins will consult with CPW in good faith to evaluate how
Halligan Releases can be protected.
Curtailment of the Winter Release Plan
The Winter Release Plan will occur from October 1 through April 30 every year except during emergency
situations, maintenance occurrences, or when severe water restrictions that prohibit all lawn watering
are in place for Fort Collins’ water customers, as described further in Section 4.2.1.7.
EXHIBIT A TO RESOLUTION 2025-083
4.2.1.2 Summer Low-flow Plan
As part of Halligan Project operations and to minimize impacts, Fort Collins will implement the Summer
Low-flow Plan, which adjusts reservoir operations by forgoing diversions and/or releasing its water
stored in the enlarged Halligan Reservoir to maintain a minimum continuous 5 cfs flow in the
approximately 22 miles of the North Fork between the replacement Halligan Dam and Seaman Reservoir
(as measured at three gaging stations along the North Fork, as described below) from May 1 to
September 30 each year (summer releases). The minimum target of 5 cfs for the Summer Low-flow Plan
was identified by Fort Collins as the amount of flow that could be maintained in the North Fork below
the enlarged Halligan Reservoir without increasing the size of the reservoir. Fort Collins will implement
the Summer Low-flow Plan the first summer after the new Halligan Dam has been approved to store
water by the DWR and Fort Collins’ portion of the enlarged reservoir has at least 3,000 acre-feet of
water. Based on analyses during the permitting process (GEI, 2016, 2018; Miller, 2017; WEST, 2017a,
2017b; City of Fort Collins, 2017; Pioneer, 2016a, 2016b, 2017b), it is projected that the Summer Low-
flow Plan will produce the following results:
• Eliminate almost all16 zero-flow days on the North Fork (in combination with the Winter Release
Plan, Section 4.2.1.1) which avoids and minimizes potential impacts on the aquatic ecosystem
including stream temperature from the Halligan Project.
• Anticipation of stream temperature benefits for the North Fork, at times, are based on recognition
that the Summer Low-flow Plan would increase flow rates on the North Fork in summer months at
the times of the lowest current flow rates. A more thorough understanding of anticipated
temperature effects of the Halligan Project on the North Fork will be developed through
temperature modeling planned for the CWA Section 401 water quality certification application.
• Result in beneficial effects to the North Fork for small-bodied native fish in the form of a more
longitudinally connected aquatic corridor compared to existing zero-flow conditions.
• Create additional wetted channel area that will benefit small-bodied fish, trout, and
macroinvertebrates (these benefits vary along the North Fork per Table 3-3).
• Re-establish basic habitat requirements for aquatic species through the reintroduction of perennial
flow.
16 See potential exceptions at end of this section 4.2.1.1 Winter Release Plan “Curtailment of the Winter Release Plan” and section 4.2.1.2 Summer Low-
flow Plan “Curtailment of the Summer Low-flow Plan”.
EXHIBIT A TO RESOLUTION 2025-083
The Summer Low-flow Plan involves bypassing the North Poudre Canal Diversion through a
reconstructed North Poudre Canal Diversion so that the water remains in the North Fork. Currently, the
North Poudre Canal Diversion does not allow for such flow bypasses.
The Summer Low-flow Plan will
also result in benefits that will
offset the impact resulting from
the inundation of approximately
0.75 mile of the CWCB’s instream
flow water right (Water Court
Case 1985CW430) on the North
Fork above Halligan Reservoir (as
discussed further in
Section 3.3.2.3).
Figure 4-2 shows a zero-flow
condition that is common near
the mouth of Phantom Canyon
during certain times of the year,
which will be improved through
the Winter Release Plan and
Summer Low-flow Plan.
Operation of the Summer Low-
flow Plan
Fort Collins will forgo diversions into and/or release water from its share of storage in the enlarged
Halligan Reservoir to maintain a minimum continuous flow of 5 cfs in the North Fork between the
replacement Halligan Dam and Seaman Reservoir from May 1 through September 30 every year.
Fort Collins will install new instrumentation and continue to monitor flows at specific locations on the
North Fork between the replacement Halligan Dam and Seaman Reservoir. Flow will be measured at the
following three specific locations:
• The existing gage or new instrumentation at or below the replacement Halligan Dam
• A new gage in and/or slightly downstream of the bypass structure for the reconstructed North
Poudre Canal Diversion
• The existing gage where West County Road 74E crosses the North Fork near Livermore
If the flows at any of the three gages drop below 5 cfs from May 1 through September 30, Fort Collins
will modify flow operations to forgo diversions into and/or make releases from its portion of the
enlarged Halligan Reservoir to increase the flow to at least 5 cfs at each of the three gages. The amount
of time required for these minor adjustments will depend on the system installed. The intention during
design will be to react within at least an hour or so, but if possible, sooner. Fort Collins understands that
maintaining 5 cfs at the gages may require releases greater than 5 cfs to compensate for potential losses
in the North Fork.
Based on Commission and public feedback, Fort Collins will also perform preconstruction surveys of the
pre-Halligan Reservoir enlargement flows on the reach of the North Fork between the existing
Livermore gage and the upstream end of Seaman Reservoir (that is, the Livermore-to-Seaman Reach) in
different seasons and hydrologic regimes (particularly dry conditions) to determine if there are flow
Figure 4-2. North Fork, Zero-Flow Conditions below Calloway
Diversion, August 2018
Source: CPW
EXHIBIT A TO RESOLUTION 2025-083
losses in this stretch. Details of the preconstruction surveys, including an agreement on methods and
standards to be used to define whether there are flow losses, will be included in an intergovernmental
agreement between Fort Collins and CPW. If the preconstruction survey demonstrates that the
Livermore-to-Seaman Reach is a neutral or gaining reach, then another gage below the existing
Livermore gage will not be needed. If the preconstruction survey demonstrates that the Livermore-to-
Seaman Reach is a losing reach, Fort Collins will coordinate with CPW on next steps which could include
the installation of a fourth gage or increased Halligan Project flows to the Livermore gage to offset such
losses toward ensuring that the Summer Low-flow Plan benefits all 22 miles of river.
If, in the future, another diversion structure is constructed in the Livermore-to-Seaman Reach, Fort
Collins will commit to work with the owner of this diversion structure toward assuring passage of Fort
Collins’ flows. The commitment with the future diversion structure owner could include a written
agreement, installation of other gages, and/or other means of assuring that Fort Collins can meet its
Summer Low-flow Plan measure.
Exchange of the Summer Releases – May through June
Similar to the winter releases, from May 1 to June 30, the Summer Low-flow Plan releases will be
delivered down the North Fork to the confluence with the Main Stem and either “exchanged up” to
Fort Collins’ Intake(s) on the Main Stem or delivered downstream for other purposes. If the summer
releases are exchanged, when the releases reach the confluence of the Main Stem and the North Fork,
Fort Collins will divert a like amount of water at one of the Fort Collins’ Intakes. The amount of water
diverted at the Fort Collins’ Intake(s) will be the amount released from the enlarged Halligan Reservoir
reduced by the administrative transit loss assessed by DWR. In certain rare conditions when inadequate
flows exist in the Main Stem for Fort Collins to perform an exchange to its intake(s), Fort Collins may find
an entity willing to accept the summer releases in exchange for transferring other water to Fort Collins.
These trades will require an agreement between Fort Collins and the other entity, and such an
agreement will be reached in the future.
Greeley may potentially divert and store the summer releases in Seaman Reservoir using its own
exchange water rights. In these situations, Greeley would divert and store the summer releases and
deliver a like amount of water to the Main Stem at some point above the downstream calling water
right. Diversion and storage of Halligan summer releases by Greeley in Seaman Reservoir at times would
occasionally interrupt the temperature benefits of the Summer Low-flow Plan in the approximately
1 river mile reach of the North Fork below Seaman Reservoir. To maximize the extent of this benefit for
the North Fork, an operational agreement is being pursued with Greeley (discussed further in
Section 4.2.1.3).
Modified Summer Release Exchange Plan – July through September
Fort Collins will not exchange Summer Low-flow Plan releases (up to 5 cfs) from Halligan Reservoir up to
either of the Fort Collins Intakes. This hiatus on exchanges will occur each year from July 1 to September
30. This action will leave more water in the Main Stem upstream of the North Fork confluence and
downstream to below the Hansen Supply Canal during times of the most critical temperature concern
(July to September), minimizing Halligan Project temperature impacts in this critical season.
Protection of the Summer Releases
NPIC cannot divert the summer flows into the North Poudre Canal pursuant to an existing agreement
with Fort Collins. Additionally, Fort Collins will undertake a good faith effort to protect the summer
releases from Halligan Reservoir to Seaman Reservoir using the Protected Mitigation Release statute
EXHIBIT A TO RESOLUTION 2025-083
(per CRS Section 37-92-102[8]) in the same manner and subject to the same limitations as described for
the winter releases (Section 4.2.1.1).
Curtailment of the Summer Low-flow Plan
The Summer Low-flow Plan will not be operated during emergency situations, maintenance
occurrences, and when water restrictions are in place for Fort Collins’ water customers, as described
further in Section 4.2.1.7.
4.2.1.3 Operational Agreement with Greeley/Seaman Reservoir Outlet Works
Reconstruction
If the diversion and storage of Halligan Project summer releases by Greeley in Seaman Reservoir could
be avoided, the river temperature benefits of the Summer Low-flow Plan could be extended to the
approximately 1 river mile reach of the North Fork below Seaman Reservoir. To maximize the extent of
this benefit on the North Fork, Fort Collins is pursuing an operational agreement with Greeley. The
agreement would specify the need for Greeley to pass Halligan Releases, including the Winter Release
and Summer Low-flow Plan of 3 cfs and up to 5 cfs directly through Seaman Reservoir. For this to be
possible, upgraded outlet works may be needed in Seaman Reservoir. Greeley is currently in the process
of upgrading their outlet works with support from federal funding. As part of the potential agreement,
Fort Collins may provide additional funding support for further refinement of the new outlet works
design for Seaman Reservoir. The goal of this additional funding would be to give the new outlet works
the functionality and operational control to pass even the small Summer Low-flow Plan releases through
Seaman Reservoir (that is, the refined new outlet works should allow for fine-scale management of
releases on the order of 1 to 5 cfs).
In the event that Fort Collins cannot reach an agreement with Greeley to pass Fort Collins’ Halligan
Winter and Summer Low-flow Plan releases of 3 cfs and up to 5 cfs below Seaman Reservoir, and the
CWA Section 401 water quality certification process determines that the Halligan Project has potential
for occasional adverse temperature impacts on the North Fork below Seaman Reservoir that requires
mitigation, Fort Collins commits to mitigating the identified temperature impacts attributable to the
Halligan Project through stream restoration or other measures in a manner agreed to by Fort Collins,
CDPHE, and CPW. If reasonably practicable, Fort Collins will mitigate the identified impacts along the
river reach from Seaman Reservoir to the confluence with the Main Stem commensurate with Fort
Collins identified impacts. If not reasonably practicable in the reach below Seaman Reservoir, Fort
Collins will work with CDPHE and CPW to find other mitigation commensurate with the Halligan Projects
identified impacts.
4.2.1.4 Ramping Rate Limitations
By applying ramping rate limitations, Fort Collins will seek to constrain existing and potential dramatic
decreases and increases in the rate of discharge from Fort Collins’ portion of the enlarged Halligan
Reservoir to avoid and minimize impacts on aquatic species, particularly small-bodied native fish and
rainbow trout. Such dramatic decreases and increases in the discharge of water below Halligan Dam
resulting from Fort Collins’ operation of its portion of the enlarged Halligan Reservoir could occur
because of (1) the rate at which Fort Collins diverts water into the enlarged reservoir (thus affecting the
amount of water flowing past the dam), and (2) the rate at which Fort Collins releases water from its
portion of an enlarged Halligan Reservoir that Fort Collins previously stored. Fort Collins will seek to
implement the ramping rate limitations by managing both such aspects of its operations.
The ramping rate limitations described in this section are intended to protect aquatic life, as well as
people recreating (for example, fishing) downstream. Tempering sudden flow changes is consistent with
EXHIBIT A TO RESOLUTION 2025-083
The Nature Conservancy’s (TNC’s) environmental flow recommendations for the North Fork (TNC 2008).
The ramping rate limitations will also help maintain a more natural descending limb of the North Fork
hydrograph following peak flows by incorporating a more gradual decrease in outflow and establishing a
lag time before returning the stream to a base flow level. The ramping rate limitations are based on an
evaluation of operations at the existing Halligan Dam and, in part, on the statistical analysis of natural
ramping rates that are anticipated on the North Fork. The following ramping rate limitations
(summarized) were developed in consideration of the following factors:
1) Needs of Fort Collins’ customers and additional legal obligations of Fort Collins
2) Operational compatibility
3) Mimicking natural hydrologic conditions to the extent feasible
4) Protecting small-bodied native fish and rainbow trout
Operation of the Ramping Rate Limitations
Fort Collins will limit dramatic decreases and increases in the discharge rate resulting from Fort Collins’
operation of its portion of the enlarged Halligan Reservoir as described in this section. Ramping rate
limitations would take effect as soon as the new Halligan Dam has been approved to store water by the
DWR.
Ramping Rate Limitations to Decreasing Discharge Rates–The limitations on decreasing discharge rates
resulting from Fort Collins’ operation of its portion of the enlarged Halligan Reservoir are intended to be
protective of small-bodied native fish and rainbow trout that are susceptible to being stranded in
discrete areas within the North Fork with sudden decreases in flow. According to the Ramping Rate
Limitations for decreasing discharge rates resulting from Fort Collins’ operation of its portion of the
enlarged Halligan Reservoir, the maximum allowable decrease in discharge rate is dependent on the
starting discharge rate, which will be measured at the outlet works of the replacement Halligan Dam
and/or the immediate downstream gage. The maximum allowable decrease to the discharge rate
resulting from Fort Collins’ operation of its portion of the enlarged Halligan Reservoir, according to the
Ramping Rate Limitations, is summarized in Table 4-1.
Table 4-1. Ramping Rate Limitations for Decreasing Releases from Fort Collins’ Portion of an Enlarged
Halligan Reservoir[a]
Starting Discharge Rate[b] Maximum Down-ramp (Decrease) per Hour
Greater than 200 cfs 10% of starting discharge rate
Between 100 and 200 cfs 10% of starting discharge rate (maximum of 20 cfs)
Less than 100 cfs 10% of starting discharge rate (maximum of 10 cfs)
[a] The replacement Halligan Dam will include an outlet works with a maximum capacity of 800 cfs; therefore, the
maximum release flow is 800 cfs if the reservoir is not full.
[b] The “starting discharge rate” is the discharge rate from the outlet works before any decrease in flow.
The following are example descriptions of how the ramping rate limitations will be implemented for
decreasing discharge rates resulting from Fort Collins’ operation of its portion of the enlarged Halligan
Reservoir:
• Example 1: Decreasing discharge rate from 800 cfs to 50 cfs (for example, after the Peak Flow
Bypass Program)–The discharges from the enlarged Halligan Reservoir will decrease or be “ramped
down” at a rate of 10 percent of 800 cfs per hour (cfs/hour) (80 cfs/hour), until a discharge rate of
EXHIBIT A TO RESOLUTION 2025-083
approximately 200 cfs is reached. This will be accomplished by managing how Fort Collins diverts
water into storage in the enlarged Halligan Reservoir. At that point, a “reset” will occur and
discharges from the reservoir will continue to decrease or “ramp down” at a maximum rate of
10 percent of 200 cfs (20 cfs/hour). As the discharges continue to decrease, another reset will occur
at 100 cfs, and the discharge rate will decrease or be ramped down at a maximum of 10 percent of
100 cfs (10 cfs/hour) until the final discharge rate is reached (50 cfs). The total duration of this
ramping event will be approximately 18 hours.
• Example 2: Decreasing discharge rate from 90 cfs to 5 cfs–The releases from Halligan Reservoir will
decrease or be ramped down at a rate of 10 percent of 90 cfs per hour (9 cfs/hour) until the final
discharge rate is reached. Again, this will be accomplished by managing how Fort Collins diverts
water into storage in the enlarged Halligan Reservoir and how Fort Collins is making releases of
water it previously stored in its portion of an enlarged Halligan Reservoir. The total duration of this
ramping event will be approximately 10 hours.
Ramping Rate Limitations to Increasing Discharge Rates–The limitations to increasing discharge rates is
intended to protect fish that could be swept downstream and to lower the risk to people recreating on
the North Fork who could be exposed to rapid water level rises without the limitation in place.
According to the ramping rate limitations for increasing discharge rates, Fort Collins will limit changes to
the rate at which reservoir discharges increase resulting from Fort Collins’ operation of its portion of the
enlarged Halligan Reservoir. Increasing discharge rates from the reservoir will be evenly distributed over
a 4-hour period to more closely match hydrographic data above Halligan Reservoir and other
unmanaged systems with similar precipitation and runoff regimes.
The following is an example description of how the ramping rate limitations will be implemented for
increasing discharge rates resulting from Fort Collins’ operation of its portion of the enlarged Halligan
Reservoir:
• Example: Increasing discharge rate from 5 cfs to 100 cfs–The discharges from Halligan Reservoir will
be increased or ramped up at a rate that is evenly distributed over a 4-hour period. In this case, the
releases from the reservoir will be increased at 24 cfs/hour.
Exclusions to the Ramping Rate Limitations
The ramping rate limitations will not apply to water that is naturally spilling over the spillway of Halligan
Dam because Fort Collins cannot control this amount of flow. Likewise, the ramping rate limitations will
not apply to NPIC’s diversion, storage, and releases of water in its portion of the enlarged Halligan
Reservoir. NPIC can, and likely will, continue to operate its portion of the enlarged Halligan Reservoir as
it does currently. Nevertheless, after construction of the Halligan Project, Fort Collins will attempt to
reach an operational agreement with NPIC to operate all diversions to and releases from the enlarged
Halligan Reservoir (both Fort Collins and NPIC’s) to meet the ramping rate limitations (Section 5.1.1.5).
The NPIC has indicated a preference to wait until after the enlarged Halligan Reservoir has been
operational for a few years before considering such an agreement.
Occasionally, Fort Collins may be required by others or by maintenance exercises to deviate from the
ramping rate limitations. Two such example scenarios when the ramping rate limitations might not be
implemented are described as follows:
• DWR currently allows some flexibility in water rights administration that would allow ramping rates
to occur at times when Fort Collins does not have the right to store water (DWR 2016). However, if
DWR guidance changes in the future, Fort Collins could be directed to cease diverting water into its
EXHIBIT A TO RESOLUTION 2025-083
portion of the enlarged Halligan Reservoir for water rights administration or other reasons. To the
extent legal Fort Collins will ramp diversions as described in this plan.
• Consistent with best practices, Fort Collins annually exercises the outlet valves to ensure full range
of operation. These activities will likely occur annually during the spring runoff when water is spilling
over the spillway. In these instances, the valves will be fully opened for several minutes and then
reduced back to the operational level.
Curtailment of the Ramping Rate Limitations
The ramping rate limitations apply only to discharges affected by Fort Collins’ operation of its portion of
the enlarged Halligan Reservoir and not to changes in the discharge rate from other factors. The
ramping rate limitations will not be operated during emergency situations, maintenance occurrences,
and when water restrictions are in place for Fort Collins’ water customers, as described further in
Section 4.2.1.7. As discussed above in “Exclusions to the Ramping Rate Limitations,” the ramping rate
limitations may also be curtailed as required by the Division of Water Resources in its administration of
water rights and regulation of Halligan Dam safety.
4.2.1.5 Peak Flow Bypass Program
Fort Collins will forgo all diversions into its portion of the enlarged Halligan Reservoir for 3 days
coinciding as closely as practicable with the annual forecasted peak (runoff) flow event for the
North Fork. The ramping rate limitations (Section 4.2.1.4) will be implemented on both sides of this
3-day Peak Flow Bypass Program, extending the bypass beyond 3 days. The Peak Flow Bypass Program
would take effect as soon as the new Halligan Dam has been approved store water by DWR.
The Peak Flow Bypass Program will avoid and minimize impacts on the aquatic ecosystem from the
Halligan Project by maintaining some of the historical, pre-enlargement peak flows past the enlarged
Halligan Reservoir. The Peak Flow Bypass Program will allow 3 days (in addition to ramping) of peak
flows during times when Fort Collins could be diverting water into storage in the enlarged Halligan
Reservoir. This Peak Flow Bypass Program is intended to mimic a natural, pre-enlargement stream flow
for this 3-day period to support riverine and ecological processes in the North Fork, such as the
following:
• Providing phenological cues to aquatic and riparian organisms for emergence of aquatic insects,
spawning, the timing of flowering, and seed dispersal
• Facilitating natural seasonal sediment transport, channel shaping, and channel scour
• Recruiting and transporting woody debris and other organic materials
• Providing overbank flooding to maintain wetland and riparian habitat function, including seed
transport and propagation of native cottonwood and willow species, sediment transport, formation
and maintenance of aquatic habitat, and riparian area diversity and structure
Operation of the Peak Flow Bypass Program
Fort Collins will monitor the stream gage installed above the enlarged Halligan Reservoir (United States
Geological Survey gage 06751145 on the North Fork), along with snowpack levels and weather
conditions, to estimate when a peak flow of runoff above the enlarged Halligan Reservoir will occur.
When the forecast peak flow has been estimated to within a few days, Fort Collins will forgo diverting
water into storage into its portion of the enlarged Halligan Reservoir for 3 consecutive days. The
ramping rate limitations described in Section 4.2.1 will be implemented on both the increasing and
EXHIBIT A TO RESOLUTION 2025-083
decreasing of flows for the 3-day bypass. The replacement Halligan Dam will include an outlet works
with a maximum capacity of 800 cfs, which will allow operational passing of the full magnitude of the
incoming peak flow via the outlet works, spillway, or a combination of each, in most years.
Operation of the Peak Flow Bypass Program will be limited to the snowpack-driven annual peak, which
typically occurs during runoff between mid-May to early June (Natural Resources Conservation Service
[NRCS] n.d.). Fort Collins will notify CPW in advance of the estimated peak flow bypass each year.
If the annual peak flow above Halligan Reservoir occurs when NPIC is filling its portion of the enlarged
Halligan Reservoir, Fort Collins will wait to operate the Peak Flow Bypass Program until directly after
NPIC fills its portion (that is, Fort Collins will bypass flows for 3 days, plus the ramping rate limitations on
both increasing and decreasing bypass flows, before starting to fill its portion of the enlarged Halligan
Reservoir). Conditions may be such that Fort Collins will be able to divert water to storage in its portion
of the enlarged Halligan Reservoir before the peak flow occurs. In this scenario, Fort Collins will
temporarily cease filling its portion of the enlarged reservoir during the estimated 3-day peak flow
bypass period.
Circumstances may exist when, in consultation with CPW, Fort Collins will deviate slightly from the Peak
Flow Bypass Program described herein, provided that any such modifications will not affect Fort Collins’
storage and yield from the enlarged Halligan Reservoir and are consistent with all applicable permits and
approvals, agreements, and decrees. These potential deviations could include changes to the timing or
quantity of flow to manage sediment buildup in Halligan Reservoir following a wildfire event; changes to
the timing or quantity of flow in a wet year to minimize predicted excessive spilling over the Halligan
Dam; other modifications of timing, duration, and quantity of flow needed for emergency response;
periodic maintenance; or for the benefit of the aquatic environment as determined in coordination with
CPW.
Limitations of the Peak Flow Bypass Program
Fort Collins will not have any dominion or control over the bypassed water because it will not have been
previously diverted or stored by Fort Collins. Therefore, as occurred historically, the peak flows will be
available for diversion by NPIC at the North Poudre Canal Diversion or by Greeley at Seaman Reservoir
under their respective water rights. Fort Collins understands that NPIC currently has rights to divert up
to approximately 350 cfs at the North Poudre Canal Diversion, although current infrastructure may limit
diversions to less than approximately 200 cfs.17 Peak flows greater than the amount that NPIC can legally
and physically divert at the North Poudre Canal Diversion will flow past the North Poudre Canal
Diversion.
Because estimating peak flow can be difficult given unpredictable weather conditions beyond Fort
Collins’ control (for example, hot, dry, or windy conditions that quickly evaporate snowpack; cool or wet
conditions that create gradual runoff with no distinct peak; or unpredictable rain on snow events), the
actual peak flow above the enlarged Halligan Reservoir might not be the same as the predicted peak
flow used for this program. If in a particular year the peak flow is difficult to estimate given
unpredictable or changing weather conditions, and is accidentally missed, the incoming flows will be
passed through the enlarged Halligan Reservoir as soon as this condition is identified. If the peak flow
bypass is operated prematurely, Fort Collins will not operate the Peak Flow Bypass Program again that
year. To minimize these circumstances, Fort Collins will monitor its Peak Flow Bypass Program actions
each year to evaluate how closely the estimated and bypassed peak coincides with the actual peak that
17 Design criteria for reconstruction of the North Poudre Canal Diversion as part of the Halligan Project are expected to support diversions of
350 cfs.
EXHIBIT A TO RESOLUTION 2025-083
occurred in a given year. This annual review will provide information to optimize the Peak Flow Bypass
Program operations over time. If for some reason Fort Collins does not accurately anticipate the peak
flow, Fort Collins will consult with CPW or other parties on methods to improve its forecasting of peak
flows on the North Fork, which will be paid for by Fort Collins.
Curtailment of the Peak Flow Bypass Program
The Peak Flow Bypass Program will not be operated during emergency situations, maintenance
occurrences, and when water restrictions are in place for Fort Collins’ water customers, as described
further in Section 4.2.1.7.
4.2.1.6 End of Summer Flushing Event
An end of summer flushing event (flushing event) will be conducted following fall turnover of Halligan
Reservoir each year that a turnover event occurs (turnover is anticipated to occur in all years of normal
Halligan Project operations) to address potential iron coatings on river materials. The first flushing event
would occur after the new Halligan Dam has been approved to store water by DWR and Fort Collins’
portion of the reservoir has filled and there has been a reservoir turnover, as described above. The
flushing event would be a release of a maximum of 30 acre-feet of water from Fort Collins’ water in the
Halligan Reservoir Enlargement to the North Fork over a short time duration. In years when releases
occur for other reasons (for example, NPIC releases) that yield similar flow rates/durations following
turnover, these flushing event releases by Fort Collins would not be needed and would not occur. Like
other flow-related operational measures (Section 4.2.1), the flushing event will not be operated during
emergency situations, maintenance occurrences, and when water restrictions are in place for Fort
Collins’ water customers as discussed in Section 4.2.1.7.
The intention of the flushing event would be to flush seasonal iron deposition (if it occurs) from
sediment surfaces below the dam to minimize the potential adverse effects of such deposition, which is
most likely to occur in late summer, if it were to occur. The goal is to release a maximum of 30 acre-feet
of water at the lowest discharge rate from the outlet of the enlarged Halligan Reservoir that is
practicable to successfully mobilize the iron deposits. Targeting lower effective flow rates is desirable to
avoid unintended adverse consequences on small-bodied fish and inadvertent sediment release. For
example, a possible release schedule would be to release about 80 cfs for 4 hours.
To avoid unintended adverse effects on small-bodied native fish and sediment, Fort Collins will seek
CPW input regarding the planned rate, ramping, and timing of the release each year. Fort Collins would
also monitor iron and habitat conditions immediately below the enlarged reservoir for 5 years to
determine if this flushing event is effective and/or necessary. This monitoring will consist of visual
checks for iron deposition on sediment in the vicinity of the NBH sampling station (and photographic
records of any observed deposition) as well as continued sampling at NBH for dissolved and total iron.
However, if it is determined at the end of the first five flushing events (in consultation with CPW) that
this operation is no longer needed, then the releases and special monitoring (observations of iron
deposition) will end.
4.2.1.7 Water Supply Shortage Events and Curtailment of Measures
To balance the protection of fish and wildlife that benefit from the flow-related operational measures
described in Chapter 4, with the health and safety of the customers who rely on Fort Collins to provide
high-quality, reliable drinking water, the flow-related operational measures described Sections 4.2.1
and 5.1.1.1 can be curtailed during certain instances that threaten Fort Collins’ ability to provide that
water. Curtailment can occur during emergency situations, maintenance occurrences, and when water
restrictions are in place for Fort Collins’ water customers, as described below. When appropriate in
EXHIBIT A TO RESOLUTION 2025-083
limited instances like planned maintenance, Fort Collins will notify CPW of curtailment events to
consider potential timing to limit impacts on aquatic resources.
Emergency Situations
Curtailment of the flow-related operational measures described in Chapter 4 can occur, at Fort Collins’
discretion, during emergency situations, such as flooding, wildfires, infrastructure failures or other
limitations, or other instances that threaten the ability of Fort Collins to deliver high-quality drinking
water safely to its customers. The frequency of anticipated curtailment for emergency situations is
difficult to define because these situations are outside of Fort Collins’ control. However, over the past
20 years, temporary curtailment due to an emergency likely would have occurred only for approximately
2 months coinciding with the 2012 High Park Fire. In contrast, certain emergency situations likely will
not require curtailment of the flow-related operational measures described above. For example, the
2020–2021 Cameron Peak Fire and associated water use restrictions likely would not have required
curtailment of Fort Collins’ operations of its portion of the enlarged Halligan Reservoir because of the
time of year that it occurred. Curtailment of the measures due to emergencies is anticipated to be
infrequent and short in duration.
Maintenance Occurrences
Curtailment of the flow-related operational measures described in Chapter 4 can occur, at Fort Collins’s
discretion, during maintenance events such as inspections, repairs, or planned maintenance of the
Halligan Dam infrastructure and related appurtenances. The number and extent of these occurrences
will generally be minimized by advanced planning, including consultation with CPW to limit impacts on
wildlife if any operational or mitigation commitments need to be modified. Maintenance activities will
inherently be short in duration because they will likely disrupt Fort Collins’ and NPIC’s ability to deliver
water to their customers and shareholders. Therefore, curtailment that occurs because of maintenance
activities is also anticipated to be infrequent and short in duration. In addition, for non-emergency
maintenance activities, the ramping rates limitations (Section 4.2.1.4) will be implemented.
Watering Restrictions
Curtailment of the flow-related operational measures could occur, at Fort Collins’ discretion, during
periods when a water shortage is projected and Fort Collins’ water customers are required to restrict
their landscape watering through mandatory water restrictions to 2 days a week or fewer. This would
balance the benefits provided to the aquatic environment from the flow-related operational measures,
with the ability to reliably provide water to Fort Collins’ customers.
Such curtailment corresponding with customers limiting landscape watering to 2 days per week or fewer
is consistent with the Level 1 action level described in the Water Shortage Action Plan (City of
Fort Collins 2020b). Although changes to future Fort Collins policy may influence changes to future
mandatory water restriction levels, curtailment of the flow-related operational measures described
previously will be independent of those future planning criteria and will instead be tied to the
restrictions currently associated with a Level 1 action level in the 2020 plan (City of Fort Collins 2020b).
For example, if future planning incorporates a new description of a Level 1 water restriction that is
3 days per week, curtailment of the flow-related operational measures will occur only when water
restrictions limit watering to 2 days per week or fewer.
The Winter Release Plan would continue to operate through restriction levels that allow lawn watering
but may be curtailed when customers are not allowed to water lawns, which is currently Level 3 of the
Water Shortage Action Plan.
EXHIBIT A TO RESOLUTION 2025-083
The water needs of Fort Collins and its customers have and will continue to change over time due to
impacts from climate change, continued conservation, economics, and other factors. Fort Collins is
currently working on future water resources and demand planning and modeling that will consider
these potential factors and the impacts to its water system. Fort Collins is committed to incorporating
this planning and modeling data about the potential of operations that will include continuing the
Summer Low-flow Plan even during greater water restriction levels. If appropriate and approved by the
City Council, Fort Collins will incorporate into future policies that the Summer Low-flow Plan operations
continue at some level even during greater water restriction levels (particularly during restriction levels
that allow lawn watering). Fort Collins will coordinate with CPW on potential changes to these
curtailment measures.
The frequency of such curtailment is expected to depend primarily on the occurrence of drought in the
region. Common technical platform (CDM and DiNatale 2013) modeling indicates that mandatory
restrictions will be required infrequently (mandatory restrictions occurred twice in an 86-year modeling
period). Fort Collins’ actual adoption of mandatory restrictions also occurs infrequently; recent
information indicates that mandatory restrictions have been required about once every 7 to 10 years
(three times in the last 20 years) and ranged in duration from 2 to 18 months. The voluntary watch level
of restrictions implemented by Fort Collins in summer 2021 to address uncertainty about the availability
and quality of Poudre River source water following the 2020 Cameron Peak Fire, likely would not have
resulted in a curtailment of the flow-related operational measures.
4.2.1.8 Combined Environmental Effects of Flow-related Operational Measures
Overall, the Halligan Project and proposed ramping rate strategy discussed in this FWMEP include
operational flow measures and peak flow bypass that will minimize negative effects of current Halligan
Reservoir operations, including dry-up conditions and current significant temperature fluctuations below
Halligan Reservoir dam (thermal shock). The operational flow measures will allow both perennial flows
and peak flows. The peak flows are needed to help maintain a more natural stream morphology and
overbank connectivity. These measures have been designed to collectively improve connectivity and
function to portions of the North Fork below the enlarged Halligan Reservoir that currently have little to
no flow during certain times of the year. The measures will provide perennial flows, minimize abrupt
changes in flows resulting from operations of the enlarged Halligan Reservoir, and maintain flows that
help support critical stream functions. Numerous analyses have been conducted to evaluate the
potential effects of the Halligan Project on the North Fork and its associated aquatic and biological
communities, including but not limited to analysis of flows and aquatic habitat availability under various
flow scenarios (GEI 2016, 2018; Miller 2017; WEST 2017a, 2017b; City of Fort Collins 2017;
Pioneer 2016a, 2016b, 2017b). The analyses show that implementing the minimization measures is
anticipated to have an overall (net) benefit to North Fork aquatic resources, including increased
ecological function of the stream system and associated riparian zone of the North Fork. The
minimization measures include the following:
•Combination of the Winter Release Plan and the Summer Low-flow Plan - Eliminate nearly all zero-
flow days on the North Fork between the enlarged the Halligan Reservoir and Seaman Reservoir and
restore continuous flow to approximately 5.8 to 12.118 acres of riffle and pool complex area
(Corps 2019). The combined Winter Release Plan and Summer Low-flow Plan will improve the
transport of nutrients, organic material, and native seed through the stream system while also
providing a net increase of at least 2.3 acres of riffle and pool habitat (the difference between the
18 Varying calculations have been used to determine the area of restored riffle pool complexes downstream of the North Poudre Canal
Diversion (Reach NF4, also known as Segment 2a). The larger area considers the entire length of NF4, and the smaller area considers only the
1.9-mile segment of NF4 above the North Poudre Canal return flow (refer to Corps, 2019 for more information).
EXHIBIT A TO RESOLUTION 2025-083
minimum 5.8-acre gain and 3.5-acre loss because of inundation), in the stretch of the North Fork
between the enlarged Halligan Reservoir and Seaman Reservoir. The Summer Low-flow Plan will also
provide a stream temperature benefit on the North Fork during the lowest summer flow rates,
which often correspond to the times of current stream temperature standard exceedances
(especially July through September). Further, the Modified Summer Release Plan will extend some
of the avoidance benefits of the Summer Low-flow Plan to Segment 10a of the Main Stem.
•Ramping Rate Limitations - Limit abrupt changes to discharges resulting from Fort Collins’ operation
of its portion of the enlarged Halligan Reservoir to minimize the potential for stranding or flushing of
small-bodied native fish and rainbow trout and to more closely mimic natural changes to the
hydrography.
•Peak Flow Bypass Program - Allow for a period of high flows to pass the enlarged Halligan Reservoir
to provide important functions for the maintenance of aquatic and riparian habitats, including those
discussed in Section 4.2.1.5.
In whole, the flow-related operational measures described in this section (in addition to other measures
described in Sections 4 and 5 of this FWMEP), could minimize impacts from the Halligan Project to
current conditions in the North Fork below Halligan Reservoir and may provide some beneficial and
long-term improvements (“functional lift”) to the aquatic resources when compared to existing
conditions. To quantify and assess the functional lift and long-term benefits of the Project at this time
and into the future is difficult without an in-depth analysis of current and future conditions and a project
monitoring plan.
4.2.2 Infrastructure Design Measures
Numerous aspects of the design of the replacement Halligan Dam and associated Project infrastructure
provide opportunities to improve current operations for environmental benefit, avoid and minimize
Project impacts, and allow mitigation measures such as the flow- and sediment-related operational
measures described in this FWMEP. One key measure incorporated into the design of the outlet works is
inclusion of a two-outlet system, a primary and an auxiliary outlet. A series of gates will be located at the
intake on the upstream side of the replacement Halligan Dam and at the valve house located on the
downstream side of the dam. This design ensures redundancy in operational function and will allow the
gates to be closed from multiple locations in the event one gate becomes inoperable, particularly in an
emergency. Gate redundancy also allows for maintenance work, structural inspections, or emergency
work at the replacement Halligan Dam or outlet works to be conducted without drawing down the
reservoir pool elevation. Although this design was not developed specifically as a Project mitigation
measure, it is a key improvement over the existing dam that will avoid potential sediment releases
associated with drawing down the reservoir for regular inspections and maintenance.
4.2.2.1 Multilevel Outlet Structure
A multilevel outlet works (MLOW) for Halligan Reservoir that would allow water to be released from one
or more elevation higher than the bottom has been discussed since the CMP was put forth in the DEIS.
An MLOW is a tool that can, in some cases, allow for beneficial additional management controls on the
quality of water released from a reservoir, particularly at times of stratification. At this time, however,
an MLOW is not expected to be necessary from the perspective of aquatic life mitigation efforts.
Therefore, based on CPW comment, the MLOW is not a commitment in the FWMEP, but the need for an
MLOW may be revisited through the CWA Section 401 water quality certification process.
During the 401 Certification process modeling and analysis findings will be reviewed to assess whether
such a structure would provide effective and practical water-quality management options for mitigating
EXHIBIT A TO RESOLUTION 2025-083
anticipated Project water-quality impacts. Currently anticipated decision factors regarding “effective
and practical water-quality management options” include consideration of reservoir stratification,
concentration gradients, operations, and net benefit to aquatic resources. For example, model results
will be evaluated to determine whether operational flexibility to release water from the epilimnion in
summer months will provide adequate water quality benefit when weighed against any additional stress
on aquatic life because of the release of warmer water from the top of the reservoir. CWA Section 401
water quality certification model findings will be shared, and CPW and CDPHE will be consulted on this
decision, as part of the CWA Section 401 water quality certification process.
4.2.2.2 Outlet Conduit Sizing
To allow for the peak flow bypass mitigation measure (Section 4.2.1.5), Fort Collins incorporated an
enlarged outlet conduit, which is larger than necessary to meet demand-based releases. The enlarged
outlet will be constructed to release up to 800 cfs. Streamflow gage measurements and Project
modeling indicate inflows into Halligan Reservoir rarely get above 800 cfs, with only 0.46 percent of days
being higher and most of these days the enlarged reservoir will be full and spilling.
4.2.3 Construction-related Measures
Fort Collins will implement multiple measures to avoid and minimize impacts on fish and wildlife related
to construction of the Halligan Project.
4.2.3.1 Big Game Interference Minimization
Fort Collins aims to avoid and minimize the Halligan
Project’s potential impacts on wildlife within the
Halligan Project Area when feasible. Figure 4-3
shows an elk herd foraging in the Livermore area.
The Halligan Project includes many construction-
related measures designed to avoid and minimize
impacts on big game, including the following
measures that are described elsewhere in this
report:
• Construction scheduling to ensure efficient
Project delivery, to limit temporal impacts and
number of seasons during which habitat is
disturbed (Section 4.2.3.13)
• Construction carpooling (Section 4.2.3.11)
• Management of fugitive dust during construction (Section 4.2.3.7)
• Minimizing construction disturbance areas and the number and footprint of construction access
roads (Sections 4.2.3.9, 4.2.3.10, and 4.2.3.14)
• Reclamation and revegetation of temporarily disturbed areas (Section 4.2.3.9)
• Implementation of a noxious and invasive weed management plan for construction and reclamation
activities (Section 4.2.3.15)
Compensatory mitigation and enhancement measures specific to bighorn sheep are described in
Sections 4.3.3 and 5.2.3.
Figure 4-3. Foraging Elk Herd
Source: CPW
EXHIBIT A TO RESOLUTION 2025-083
4.2.3.2 Preconstruction Botanical Surveys
Previous botanical surveys have not located Ute ladies’-tresses
orchid (Figure 4-4) in the area of Halligan Reservoir
(WEST 2016b; Jacobs 2021). To further minimize the possibility
of Project impacts on this federally threatened plant, botanical
surveys will be conducted at a minimum of a year before
construction. Surveys will focus on areas that will likely be
disturbed by the Halligan Project and that could support the
orchid, and be performed during the growing season (July and
August). Results of preconstruction surveys will be submitted to
USFWS as required by the ESA; CPW will be provided a courtesy
copy of results. If Ute ladies’-tresses orchid is found during
preconstruction surveys, Fort Collins will develop a plan to avoid
the plants and the habitat or remove and relocate the plants
before construction disturbance.
4.2.3.3 Preconstruction Bat Surveys
Visual and auditory detection surveys for bats (Figure 4-5) were
conducted in the area of Halligan Dam and up to 0.5 mile
downstream of Halligan Dam in 2021 (Jacobs 2021). Several lone
bats were detected during the surveys, but no large
concentrations of bats were identified. The scattered occurrence
of lone bat detections suggests that the area below Halligan Dam
is used for foraging, but evidence of a bat colony or identification
of roosting locations was not observed during this brief
presence/absence survey. To minimize the possibility of Project
impacts on bats, additional surveys are warranted, including a
survey for roosting sites near the dam. This additional bat survey
work will be conducted in the year before construction
commences for the Halligan Project. Surveys will focus on areas
that will likely be disturbed by Halligan Project construction
activities. If surveys indicate the presence of an active bat roost
near the Halligan Dam, Fort Collins will consult with CPW on
appropriate mitigation measures.
Figure 4-4. Ute Ladies’-tresses
Orchid
Source: P. Hickey
Figure 4-5. Townsend’s Big-Eared
Bat
Source: CPW
EXHIBIT A TO RESOLUTION 2025-083
4.2.3.4 Migratory Bird and Raptors Surveys
Nest surveys were conducted in the area of Halligan Dam and along access roads in 2021 (Jacobs 2021).
Additional monitoring for migratory birds and raptors will be performed every other year before
construction, the year before the start of construction, and annually during construction with a focus on
areas of suitable habitat within planned or proposed disturbance areas in the immediate Halligan
Project Area. Before and during construction activities, Fort Collins may use bird nesting deterrents
during nesting season to reduce the risk of nesting activities during construction. Deterrent measures
may include modifying or removing attractive nesting habitat (for example, trees, shrubs, tall grass)
within potential disturbance areas during inactive periods to reduce the potential for construction-
related impacts during active nesting periods. Before Project implementation, Fort Collins will provide
CPW an opportunity to review and comment on Project specifications related to migratory bird and
raptor nesting avoidance and minimization. If eagle or other raptor nests are identified, Fort Collins will
consult with CPW and their buffer guidelines for nesting raptors to determine measures to minimize the
potential adverse impacts of the construction activity. If avoidance and minimization techniques are
unsuccessful and a taking is necessary, Fort Collins will follow any applicable permit and mitigation
requirements at the time of the taking.
4.2.3.5 Raptor Nesting or Roosting Platforms
Fort Collins will include nesting or roosting platforms (Figure 4-6)
near Halligan Reservoir to encourage eagles and other raptors,
such as osprey, to use the reservoir. The platforms will also
minimize any temporary loss of perching locations from the
inundation of shoreline trees while new shoreline habitat
becomes established. The final design and location of nesting or
roosting platforms will be developed in coordination with CPW.
The nesting or roosting platforms will be installed as part of the
project construction. At this time the exacting timing is not
known. However, the nesting or roosting platforms will be
installed before inundation of the enlarged Halligan Reservoir
begins.
4.2.3.6 Stormwater Management Plan
Fort Collins will develop a stormwater management plan in
compliance with local and state requirements and as required by
the National Pollutant Discharge Elimination System,
Construction General Permit, COR400000, before construction, which will include all necessary
stormwater management controls and best practices, temporary sediment and erosion control during
construction, and medium-term sediment and erosion control during vegetation re-establishment.
Targeted planning and successful execution of the stormwater management plan will reduce the
potential for water quality degradation of the North Fork and its associated aquatic ecosystem.
Additionally, a non-stormwater discharge permit and monitoring plan will be prepared, if required,
before the start of construction.
4.2.3.7 Best Management Practices
Fort Collins proposes to employ standard construction BMPs (also called control measures) typically
included in federal, state, and local permit requirements to reduce potential construction-related
impacts on upland and aquatic habitats, fish, and water quality. BMPs will be implemented at Project
Figure 4-6. Raptor Nesting
Platform in Laporte, Colorado
Source: Colorado Department of
Transportation
EXHIBIT A TO RESOLUTION 2025-083
construction areas, including dam construction and staging/stockpile areas, along access roads, the
North Poudre Canal Diversion structure, and mitigation or enhancement sites that involve Fort Collins-
led construction. At a minimum, standard dust and erosion control measures, sediment control
measures, aquatic nuisance species measures, and the application of non-stormwater-related control
measures will be implemented.
The following sections list and briefly describe some of the BMPs that may be implemented during
construction to control erosion and sedimentation. Additional measures may be incorporated if those
described differ from permit conditions defined in the CWA Section 401 water quality certification and
CWA Section 404 permit, or if site conditions warrant them.
Erosion Control Measures
Erosion control or soil stabilization includes measures that are designed to prevent soil particles from
detaching and becoming transported in stormwater runoff. Erosion control BMPs protect the soil
surface by covering and/or binding soil particles. The following practices will be implemented to provide
temporary and/or final erosion control during construction:
• Preserve existing vegetation where practicable
• Control the area of soil-disturbing operations to the extent practicable to limits shown on plans
• Control erosion in concentrated flow paths by applying erosion control blankets, check dams,
erosion control seeding, or alternate methods
• Apply permanent erosion control to the remaining disturbed soil areas before the completion of
construction
The following temporary erosion control BMPs may be implemented to control erosion on the
construction site:
• Preservation of existing vegetation, when practicable, through barrier fencing
• Hydraulic mulching or hydroseeding of disturbed areas, and reseeding and revegetating with native
vegetation following construction
• Application of soil binders to aid in minimizing wind and rain erosion
• Covering of soil stockpiles, exposed areas, or inactive areas with geotextiles, mats, soil binders, or
linear erosion controls to prevent erosion from wind or rain events
• Earthen berms, drainage swales, or slope drains constructed to direct stormwater away from
disturbed areas
• Velocity dissipation and/or streambank stabilization measures to prevent scour in discharge areas
• Soil roughening to minimize erosion and allow for moisture retention and aid in seed germination
and vegetative growth
• Soil stabilization measures such as wood chips, rip rap, rock, or gravel to stabilize soil and prevent
erosion
EXHIBIT A TO RESOLUTION 2025-083
Sediment Control Measures
The following temporary sediment control BMPs may be implemented to control sediment on the
construction site:
• A silt fence, wattle, fiber roll, gravel bags, or other type of perimeter control may be installed around
the limits of construction
• Sediment basins and/or traps will be used to remove sediment before releasing water back to the
river or reservoir at a controlled rate
• Check dams constructed of fiber roll, gravel bags, or rock may be used in combination with swales to
control velocity of flows through the swales
• Passive treatment may be used to allow settlement of suspended sediment and potential passive
treatment through a media filter, before discharge
• Measures may be installed on roads and at construction exit points to reduce sediment track-out by
construction vehicles and equipment, including water bars, rock material, and reusable rockless
track-out control mats
• Stabilized construction roads may be constructed through the site to minimize dust and erosion and
help contain vehicle traffic to designated drive areas
Dust Suppression Measures
A plan for controlling fugitive dust will be developed and implemented to minimize fugitive construction
dust generated from the use of access roads and construction areas. Water and/or EPA-approved
drinking water and wildlife-safe dust palliatives will be used to stabilize construction roadways, reduce
fugitive dust emissions, and control and suppress dust in construction and access road areas. To reduce
the potential for wildlife conflicts on construction roads, magnesium chloride will not be used because it
can attract big game, such as bighorn sheep.
Non-stormwater Controls and Waste and Materials Management
The following non-stormwater control BMPs may be implemented to control sediment on the
construction site:
• Water conservation practices will be used during construction in a manner that avoids causing
erosion and the transport of pollutants offsite.
• Dewatering operations related to water captured from construction areas will comply with
applicable local and Project-specific permits and regulations. Water from dewatering operations will
meet all discharge requirements and water quality certification before water is allowed to leave the
site.
• Temporary stream crossings will be constructed to prevent construction equipment from tracking
sediment and other pollutants into the stream. Temporary stream crossings will be constructed in a
way to minimize impacts on stream banks and stream bottom substrate. It may be necessary to
install blankets between the existing substrate and temporary fill or to use clean gravel material to
construct a crossing.
• Clear water diversions will be used to intercept clear surface water runoff upstream of the
construction area and transport it around the work area to a discharge location downstream with
minimal water quality degradation. Clear water diversions used may include diversion ditches,
EXHIBIT A TO RESOLUTION 2025-083
berms, slope drains, K-rails, rock bags, gravel bags, sandbags, wood, geotextile and rubber bladders,
earthen cofferdams, filter fabric, turbidity curtains, swales, pipes, or flumes along with numerous
proprietary designs. The selection of which diversion or isolation technique to use will depend upon
the type of work involved, physical characteristics of the site, and the volume of water flowing
through the Halligan Project during each construction milestone.
• Washing of construction vehicles and equipment onsite will be done in a manner that captures wash
water, not allowing it to discharge to Halligan Reservoir or the North Fork. Containment of wash
water will minimize any potential release of contaminated wash water.
• To prevent the potential spread of invasive aquatic species in Halligan Reservoir, the North Fork, or
the Main Stem, contractors will follow State of Colorado requirements for inspections and
decontamination. If heavy equipment used for the Halligan Project was previously used in another
stream, river, lake, pond, or wetland, a specific procedure will be implemented to ensure that all
mud and debris is removed from equipment prior to entering the construction site (for example,
tracks, turrets, buckets, drags, teeth). Additional discussion of aquatic nuisance species and
decontamination to avoid their spread is in Section 4.2.3.16.
• Fueling activities will be done by a mobile fueling service within the specified fueling areas for the
construction site, which will be located away from wetlands, drainages, and riparian areas which are
also associated with higher quality wildlife habitat for a variety of species.
• Construction vehicle maintenance and repair will be conducted in an area with minimal potential to
discharge to receiving waters. Repairs may be conducted in the active construction areas, if
necessary, but soil in the area will be protected before any maintenance work. Contamination of
stormwater or construction water during the concrete curing process will be prevented. Weather
will be monitored before concrete pours to avoid potential rain events that may wash fresh
concrete into waterways. Proper perimeter controls and washout procedures will be used during
the concrete finishing process. For example, chemical curing or wet blanket or similar method will
be used that maintains moisture while minimizing the discharge.
• Chemicals and waste material will be stored properly to avoid non-stormwater discharge.
• Construction operations will occur near Halligan Reservoir and the North Fork. Therefore, care with
materials and equipment will be observed to ensure that equipment and/or materials do not enter
these waters.
• Demolition of existing structures will occur near Halligan Reservoir and the North Fork. Care with
trash and equipment will be observed to avoid and minimize potential for demolished materials to
enter these waters.
• Because of the remote location and need for concrete processing, a temporary batch plant will be
placed onsite for concrete activities. The plant will be contained to minimize the release of any
pollutants. Perimeter controls will be placed around the batch plant, and raw materials will be
stored in a manner to minimize the release of materials from rain or wind events.
• If a temporary aggregate plant is needed, water used in the processing of aggregates will be stored
in ponds and recycled. Ponds will also capture sediments from stockpiles. Pond levels will be
managed so that they do not result in non-stormwater discharge. Stormwater run-on will be
minimized and diverted around the aggregate processing area.
EXHIBIT A TO RESOLUTION 2025-083
Materials Management and Waste Management
Materials management control practices include implementing procedural and structural BMPs for
handling, storing, and using construction materials to prevent the release of those materials into
stormwater discharges. The amount and type of construction materials to be used at the site and waste
materials generated will be identified as the site development plan progresses.
Waste management includes implementing procedural and structural BMPs for handling, storing, and
ensuring proper disposal of wastes to prevent the release of those wastes into waterways. Materials and
waste management pollution control BMPs will be implemented to minimize stormwater contact with
construction materials and wastes and to prevent materials and wastes from being discharged offsite.
The following BMPs may be implemented to handle materials and control construction site wastes
associated with construction activities:
• Materials will be stored at designated areas and in a manner that prevents the release of pollutants,
such as metals, chemicals, or organic matter.
• Workers on the site will be informed about the materials stored onsite and their various health and
safety properties. Procedures for improving the effectiveness of material use while lowering
inherent environmental risks will be developed and implemented.
• Stockpiles will be located in an area where environmental impacts are minimized. Perimeter
controls will be put in place to prevent the migration of stockpiled materials. Stockpiles will be
stabilized for wind and covered if rainfall is anticipated.
• Plans and/or practices will be developed and implemented specific to the following:
– Spill prevention
– Materials handling
– Solid waste management
– Hazardous waste management
– Contaminated soil management
– Concrete waste management
– Sanitary waste management
– Liquid waste management
– Revegetation plan
CPW will have an opportunity to review and comment on the revegetation plan.
4.2.3.8 Existing Dam for Construction Sediment Control
Leaving the original dam in place during construction to act as a coffer dam provides strong control of
sediment to allow for avoidance of an inadvertent major release of sediment during construction. The
existing dam will continue to function normally during the entire time the replacement dam is being
constructed; therefore, drawdown of the reservoir will not be necessary during construction. Once the
replacement dam is complete, Fort Collins anticipates that a coffer dam will be put in place around the
existing dam during the brief (a few months or less) demolition period. Fort Collins is exploring whether
to fully or partially remove the existing dam. The determination of full versus partial demolition will
consider demolition methods and their potential direct and indirect resource impacts. If full demolition
is not pursued, certain elements of the existing dam may be retained following construction of the
replacement Halligan Dam and would generally be submerged following filling of the enlarged reservoir.
Design of the existing dam elements, if retained, would incorporate features to maintain reservoir
mixing and avoid or minimize potential impacts on water quality, such as notching the existing dam to
EXHIBIT A TO RESOLUTION 2025-083
the reservoir bottom and removing the upper portion of the existing dam. At this time, details on the
extent, methods, and impacts related to dam demolition are not known. Fort Collins will consult with
CPW as needed on the dam demolition.
4.2.3.9 Construction Disturbance Minimization and Reclamation
Fort Collins will reclaim temporarily disturbed areas following construction completion. Materials
stockpile and borrow areas created on Fort Collins’ property may be left in place for long-term
operations and maintenance of the enlarged Halligan Reservoir. Reclaiming disturbed areas to their
current condition will reduce the permanent footprint of the Halligan Project and reduce the potential
for long-term ecological degradation. Revegetation and monitoring is described in Sections 4.2.3.7
and 4.2.3.15.
4.2.3.10 Access Road Minimization and Reclamation
To construct the Halligan Project, and to implement some of the mitigation measures described herein,
construction equipment access to the site features will be required. Access roads are shown in the
detailed Project Area maps presented in Appendix A. To minimize disturbance to local residents, wildlife,
and undisturbed lands, Fort Collins proposes using existing roads whenever possible.
To accommodate larger vehicles and equipment necessary to construct the Halligan Project, existing
roads will require some or all of the following: temporary widening to accommodate two-way truck
traffic in some locations, placement of new culverts at drainage crossings, grade modifications, and road
stabilization. Fort Collins proposes to reclaim access roads to their current condition following
construction completion. Widened roads and turnouts created on Fort Collins property may be left in
place for long-term operations and maintenance of the enlarged Halligan Reservoir; widened roads may
be left in place on private property if requested by the landowner. Using existing roadways and
reclaiming widened roadways to their current condition will reduce the permanent footprint of the
Halligan Project and reduce the potential for long-term ecological degradation.
4.2.3.11 Traffic Impact Minimization
The Halligan Project is in a relatively remote location that is inaccessible to public traffic. Traffic impacts
on residents will be limited to predominant ingress and egress from Highway 287, with less ingress and
egress from Larimer County Road 80C (Cherokee Park Road). To minimize impacts on traffic on
Highway 287, Fort Collins will construct a temporary or permanent turn lane and/or an acceleration
lane. This minimization measure will be designed and implemented in coordination with the Colorado
Department of Transportation and Larimer County.
Given the complexity of construction activities associated with the Halligan Project, large amounts of
staff will be required to access the construction zone throughout Project construction. When
appropriate and feasible, such as during shift changes, Fort Collins will incorporate carpooling of staff to
and from construction areas. Carpooling of staff will reduce traffic on access roads and minimize air
quality impacts, greenhouse gas emissions, potential wildlife and vehicle collisions, and fugitive dust
during construction.
Fort Collins’ efforts to minimize traffic impacts on wildlife as noted here, as well as Sections 4.2.3.1,
4.2.3.7, and 4.2.3.9, will minimize impacts on wildlife by using existing roads, reducing traffic-related
equipment emissions and noise, reducing fugitive dust, reducing the potential for wildlife vehicle
collisions, and reducing displacement and disturbance of habitats adjacent to construction activities and
access roads. Construction of a temporary river crossing on the North Fork below the replacement dam
will minimize traffic along County Road 80C by allowing direct access to the west side of Halligan Dam
during construction (Section 4.2.3.14).
EXHIBIT A TO RESOLUTION 2025-083
4.2.3.12 Construction Impact Minimization that will Benefit Wildlife
Construction of certain elements of the Halligan Project are anticipated to occur throughout all hours of
the day or night during certain construction milestones. However, Fort Collins proposes to minimize
nighttime construction activities that have the potential to generate increased noise levels, such as
blasting, and will proactively respond to noise complaints. Lighting impacts associated with Halligan
Project nighttime construction activities will be minimized in consideration of both local residents and
wildlife. Lighting during construction will be limited to what is necessary for safety and security on the
Project site during construction. Lighting will be angled and shielded to avoid light pollution and impacts
on neighbors and wildlife. Noise will be minimized to the extent practicable during construction; Fort
Collins plans to fit equipment with mufflers and apply construction standard practices for noise
construction (the specific practices will depend on equipment used). Fort Collins’ contractors will comply
with Larimer County ordinances or approved variance requests through the county that may include
noise shielding and reduction of after-hours activities.
4.2.3.13 Construction Timing Restrictions at the North Poudre Canal and Calloway
Diversions
To minimize potential construction-related disturbance to bighorn sheep spring and fall movements,
Fort Collins and CPW have agreed to implement a 1-year construction window for both the North
Poudre Canal and Calloway Diversions. During the 1-year construction window, Fort Collins will perform
work in two phases. During the first phase, work on the access road construction, and staging
equipment and materials at the North Poudre Canal and Calloway Diversions will occur in July and
August. Then during the second phase, both the North Poudre Canal and Calloway Diversions
construction work will commence in November and conclude in March before spring movements by
bighorn sheep through the mapped linkage area (Figures 3-3 and 4-8) between the two diversion
structures. To the extent reasonably possible, all work will be completed within one construction season
beginning in November and ending the following end of March (Figure 4-7). In the unlikely event of an
unforeseen occurrence such as extreme snow, Fort Collins will coordinate with CPW to develop a
revised schedule. In addition, Fort Collins has not yet come to an agreement with landowners to
complete channel improvements and modifications of the Calloway Diversion. Should a delay occur that
affects the proposed timing restriction schedule, Fort Collins will coordinate with CPW and landowners
to discuss an alternative timeline to avoid or minimize impacts to bighorn sheep as discussed in
Sections 4.2.3.17, 4.2.3.19, and 5.1.1.4.
Figure 4-7. Proposed Construction Schedule to Avoid and Minimize Bighorn Sheep Disturbance at
North Poudre Canal and Calloway Diversions
EXHIBIT A TO RESOLUTION 2025-083
4.2.3.14 Limited Use of Western Access Road
Following completion of the temporary construction access crossing of the North Fork below the
Halligan Dam, which is planned in the first year of construction, use of the western access road
(Figure 1-3) intersecting Larimer County Road 80C (Cherokee Park Road) will be reduced to only
occasional or as-needed access from April to July in the second and subsequent years of construction to
reduce construction vehicle disturbance to wildlife in the area. Occasional use of the access road may be
required for construction access and material deliveries during certain construction milestones.
4.2.3.15 Noxious and Invasive Weed Control and Revegetation
Fort Collins will develop a noxious and invasive weed management plan for construction activities, in
coordination with the Larimer County Weed District. No domestic sheep or goats will be used for weed
control on City owned property or easements Fort Collins grants to others in the vicinity of Halligan
Reservoir. Noxious weed BMPs, including chemical, cultural, and mechanical measures, will be
implemented during all construction phases for all Halligan Project disturbance areas, including access
roads and buffers. Equipment will be cleaned so that it is free of accumulated soils that may carry
noxious and invasive weed seeds to the Halligan Project Area. Restoration and revegetation will be
completed for all temporarily disturbed areas using native plants. These disturbance areas will be
monitored after construction to ensure successful re-establishment of vegetation in accordance with
Construction General Permit requirement to stabilize all disturbed soil areas (Section 4.2.3.9) before
completion of the Halligan Project. Specific revegetation/restoration details will be identified following
final design.
4.2.3.16 Aquatic Nuisance Species
Fort Collins will take a proactive approach to preventing the introduction of aquatic nuisance species
into Halligan Reservoir, the North Fork, and the Main Stem. Non-native species and invasive species
pose a threat to ecosystems, and Fort Collins will minimize the risk of spreading aquatic nuisance species
through implementation of BMPs to prevent the potential spread of these species in Halligan Reservoir
and in the rivers. Fort Collins will implement specific procedures to ensure that all equipment is cleaned
of mud and debris (for example, tracks, turrets, buckets, drags, teeth), and inspected to confirm they are
free of aquatic nuisance species. Specific decontamination measures for equipment or materials that
were used in any stream, river, lake, pond, or wetland within 14 days of the start of the Project to
prevent the spread of New Zealand mudsnails (Potamopyrgus antipodarum), zebra mussels (Dreissena
polymorpha), quagga mussels (Dreissena bugensis), invasive plant species, and other aquatic nuisance
species will follow the most current guidance from CPW and are expected to include one or more of the
following methods: (1) Remove all mud and debris from equipment (tracks, turrets, buckets, drags, and
teeth) and spray/soak in a 1:15 solution of Quat 4 or Super HDQ Neutral institutional cleaners and
water. Keep equipment moist with the solution for at least 10 minutes, or (2) remove all mud and debris
from equipment (tracks, turrets, buckets, drags, and teeth) and continuously spray/soak equipment with
water that is hotter than 140 degrees Fahrenheit for at least 10 minutes. Hand tools, boots, and any
other equipment that will be used in the water will be cleaned, as well.
4.2.3.17 Bighorn Sheep Habitat and Collaring Measures
Fort Collins developed bighorn sheep mitigation measures in consultation with CPW to mitigate
potential direct and indirect effects of the Halligan Project within the Lone Pine herd range. The goals of
Fort Collins’ bighorn sheep mitigation package include the following:
• Avoid potential impacts by improving bighorn sheep habitat opportunities and water access in areas
away from Project construction, as described in this section
EXHIBIT A TO RESOLUTION 2025-083
• Monitor movements of the Lone Pine herd before, during, and after construction to fill a data gap
around herd habits and to support implementation of other bighorn sheep mitigation measures
through a collaring study, as described in this section
• Avoid and minimize construction-related direct and indirect impacts through a set of BMPs
(Section 4.2.3.7) and construction timing restrictions (Section 4.2.3.13)
• If, despite the forgoing measures, the Project results in one or more mortalities of a bighorn sheep
in the Lone Pine herd, financially compensate CPW for that unavoidable resource loss (Section 4.3.3)
As discussed in Section 3.8.4.1, comingling with domestic sheep and goats is the largest anticipated
threat to bighorn sheep. Fort Collins has explored numerous options to either permanently or
temporarily remove domestic sheep and goat grazing from the area around Halligan Reservoir. To date,
Fort Collins’ attempts have been unsuccessful, as discussed with CPW in multiple meetings in 2021
and 2022. Fort Collins is willing to continue exploring opportunities toward that goal of removing
domestic sheep from around Halligan Reservoir; however, a specific implementable mitigation measure
has not been identified.
4.2.3.18 Bighorn Sheep Habitat Improvements
To improve bighorn sheep habitat opportunities and water access on the Cherokee SWA, Fort Collins will
provide CPW with $250,000 for chemical treatment to abate invasive cheatgrass over at least 500 acres,
along with installation of two remote passive water sources. Fort Collins intends to provide to CPW
enough funding to complete a minimum of one round of cheatgrass treatment over 500 acres and other
habitat improvements that may include the installation of up to two water features at least 2 years
before the start of Project construction in an effort to entice bighorn sheep away from construction
areas and areas at times used for the grazing of domestic sheep. Any remaining monies up to the
$250,000 earmarked for vegetation and habitat restoration could be used by CPW for habitat treatment
on additional acreages within the Cherokee SWA.
CPW has identified several areas within the Cherokee SWA that would provide the largest benefit to
bighorn sheep habitat and foraging through cheatgrass mitigation. Trail cameras will be deployed during
and after treatment to identify how well the treatment worked. The habitat treatment targets
cheatgrass seed germination, allowing for higher quality native forage to grow, which, in turn, may keep
the Lone Pine herd within the boundaries of Cherokee SWA longer and away from domestic sheep
during the April to July grazing period. The treatment should not alter normal migration routes, habitat
range use, or lambing areas. The objective is to begin the cheatgrass mitigation treatments on a
minimum of 500 acres commencing at least 2 years before the start of the Halligan Project and continue
as needed through construction and up to 2 years postconstruction.
CPW will consider installing one or two water features in high-use bighorn sheep areas within or near
the area(s) treated to control cheatgrass. If additional water features are appropriate for the area, Fort
Collins anticipates that CPW will install either two water guzzlers for precipitation capture or one water
guzzler and one stock-tank type structure that uses water from a spring that CPW holds rights to
develop. CPW will also consider location and design elements that would exclude domestic ruminants
from using the water sources, such as wildlife friendly fencing, to minimize the potential for pathogen
transmission. These features will passively (that is, external power source not needed) provide water
sources away from Halligan Project disturbances and are expected to provide benefit before, during,
and after construction. The water features will be used to enhance bighorn sheep habitat in areas that
may be underused due to lack of water resources and within a reasonable distance of the priority
habitat restoration area noted previously.
EXHIBIT A TO RESOLUTION 2025-083
4.2.3.19 Bighorn Sheep Collaring Study
Fort Collins will provide CPW additional funding of up to $120,000 to support global positioning system
(GPS) collaring and disease testing of bighorn sheep from the Lone Pine herd to track their movements
before, during, and immediately after Halligan Project construction. GPS collaring study results will
support evaluation of whether construction may influence herd habits, in particular with respect to
interactions with domestic sheep and/or other bighorn herds. CPW will implement the collaring study
and disease testing. Disease testing will occur in conjunction with every collar application throughout
the collaring study. GPS collar monitoring studies are needed to assess disease risk and habitat
restoration needs for the Lone Pine herd by gathering data on herd landscape use (habitat, spatial, and
temporal), recruitment, and overall health. Depending upon the Lone Pine herd size, up to a maximum
of 15 GPS collars and disease testing may be deployed. The preconstruction portion of the GPS collaring
study will begin no less than 2 years before the anticipated start of the Halligan Project construction.
GPS collars are expected to have a 2-year life and collect data approximately every 4 hours.
Preconstruction collaring data will be considered viable for 5 years. Should construction be pushed
beyond that initial 5-year window, a second GPS collar study would start 1 year from the start of
construction. The intent of the second preconstruction GPS collar study is to have accurate and recent
data on the Lone Pine herd’s movements before construction. The Lone Pine herd will be fitted with GPS
collars during all of the construction with collars having an anticipated 2-year battery life. The final
phase will be a 2-year postconstruction GPS collaring event to evaluate postconstruction movement and
habitat use. CPW may euthanize bighorn sheep to prevent disease spread in the Lone Pine herd and/or
adjacent herds. As discussed in Section 4.3.3, Compensatory Mitigation for Halligan Project Impacts on
Bighorn Sheep, Fort Collins will provide a monetary compensation for any bighorn sheep culls from the
Lone Pine herd.
4.2.4 Overhead Power Line and Pole Relocation
The Halligan Project will require the relocation of approximately 27 overhead power poles and lines
from the southwest end of the existing reservoir to the new dam since the old power poles would be
inundated during the Halligan enlargement. The existing poles and line are too old to be reused safely.
The new poles and line will be constructed and energized prior to removal of old poles and line.
Installation and removal of overhead power line and poles will result in temporary disturbance of
vegetation due to vehicles driving off-road. At this time, a formal access road is not being proposed for
installation or removal of the overhead power lines and poles. Some vegetation will be permanently
removed for placement of the new poles. Fort Collins will work with Poudre Valley Rural Electric
Authority to perform raptor and migratory nesting bird surveys (Section 4.2.3.4, Migratory Bird and
Raptor Surveys) prior to construction. In addition, construction BMPs (Section 4.2.3.7, Best Management
Practices) including sediment control and aquatic nuisance species measures (Section 4.2.3.16, Aquatic
Nuisance Species), and construction disturbance minimization and reclamation measures
(Section 4.2.3.9, Construction Disturbance Minimization and Reclamation) will be implemented.
Installation and removal of the overhead power lines and poles will be prohibited between December 1
and April 30. The overhead power lines and poles will follow design guidelines similar to those used by
the Avian Power Line Interaction Committee, and will have bird diverters.
4.2.5 Halligan Reservoir Sediment Management Plan
A sediment management plan will be developed for Halligan Reservoir that will provide guidelines for
postconstruction reservoir operations (including low water level operations) to avoid adverse sediment
release events. Operating the reservoir, particularly at low water levels, in accordance with a plan
developed by sediment experts is intended to avoid adverse sediment release events like the one in
EXHIBIT A TO RESOLUTION 2025-083
1996 (described in Section C3.4). CPW will be given an opportunity to comment on the draft sediment
management plan.
4.3 Compensatory Mitigation Measures
The goal of mitigation is to avoid and minimize adverse impacts of a project, and then compensate for
any unavoidable impacts that remain. Fort Collins proposes a robust set of measures described in
Section 4.2 that will not only avoid and minimize adverse effects from the Halligan Project but also will
result in a net improvement of the aquatic ecosystem in the North Fork. However, because of the nature
and scope of the Halligan Project, some unavoidable impacts are expected and will be offset through
compensatory mitigation.
Fort Collins, in consultation with CPW, CDPHE’s WQCD, cooperating agencies, and other stakeholders,
has developed the compensatory mitigation measures described herein to compensate for impacts from
the Halligan Project that cannot be avoided or minimized. This section presents compensatory
mitigation measures specific to fish and wildlife resources, organized by general resource category. The
natural resource mitigation measures are highly interrelated and typically serve to mitigate impacts on
several ecological functions through one measure. Some of these connections (or overlaps) of mitigated
functions are explained with each measure. The table in Appendix B summarizes each avoidance,
minimization, and compensatory mitigation measure.
Throughout Project planning and mitigation proposal development, Fort Collins’ focus for compensation
has been to mitigate as close to the location of Halligan Project impact as practicable. Compensatory
mitigation for fish and wildlife will occur near the Halligan Project Area or in the North Fork watershed.
4.3.1 Preservation as Early Compensatory Mitigation Measure
In 2003 to 2004, as an act of early mitigation in anticipation of the Halligan Project, Fort Collins led the
purchase and preservation of a permanent conservation easement of a 4,557-acre property known as
Roberts Ranch, which comprises several disconnected parcels (Figure 4-8) in the Livermore Valley. The
preservation of the Roberts Ranch property was the first step in Fort Collins’ compensatory mitigation
approach for the Halligan Project. According to the CPW species activity mapping data (CPW 2020b), all
parcels are within the overall ranges of several of the state-listed species and other Tier 1 and Tier 2
species. Specifically the conservation area provides potential habitat for bald eagle, black-tailed prairie
dog, Townsend’s big-eared bat, common garter snake, and northern leopard frog, all of which are state-
listed species. Fort Collins acquired an undivided 60 percent interest in the conservation easement by
funding 60 percent (or $1.8 million) of the $3 million cost in partnership with Larimer County, Great
Outdoors Colorado, TNC, and the Roberts family. The easement covers 4,557 acres of high-quality
wildlife habitat and rangelands near Halligan Reservoir and is also adjacent to 14,000 acres of other
state and locally protected lands (Figure 4-8). This early conservation effort provides the following
benefits:
• Direct and indirect ecological benefit to wildlife resources affected by the Halligan Project, including
long-term preservation of suitable habitat for big game ungulates, as well as the federally and state
threatened Preble’s meadow jumping mouse and the federally threatened Ute ladies’-tresses orchid
• Land preservation and conservation in perpetuity of habitat for wildlife and rare and native plants,
and conservation of the diverse forest, shrubland, meadow, and riparian vegetative communities
• Approximately 2 decades of land preservation before disturbance from the Halligan Project
construction activities
EXHIBIT A TO RESOLUTION 2025-083
• Preservation of areas within the linkage area for the Lone Pine bighorn sheep herd where individual
rams have been observed annually by local residents from approximately March to October on
parcels of Roberts Ranch east of Highway 287 (Thode, pers. comm. 2021), and limitations on grazing
such that species other than cattle or horses cannot be grazed on the property unless approved by
TNC in areas where use of cattle or horses is impractical
• Conservation of more than 8.8 miles of perennial streams
• Direct connectivity to 14,000 acres of adjacent state and locally protected lands
In addition to these benefits, this early mitigation effort removed 4,557 acres of property from future
development, which equates to approximately 120 to 250 residential units based on Larimer County
Rural Open Development standards (Larimer County 2021), and eliminated the potential to increase
agricultural development within the area. To preserve this land at today’s market rates, the cost to
Fort Collins will be approximately $2.6 million. By protecting the Roberts Ranch property in 2004, Fort
Collins commenced mitigation efforts early, which has already preserved a threatened ecosystem and
the ecological functions it provides for almost 2 decades.
EXHIBIT A TO RESOLUTION 2025-083
Figure 4-8. Land Ownership and Mitigation Areas around Halligan Reservoir
EXHIBIT A TO RESOLUTION 2025-083
4.3.2 Fish Passage at the Fort Collins Intake at Gateway Park
Fort Collins will construct fish passage around the
Fort Collins Intake diversion structure at Gateway
Park (Figure 4-9) to increase connectivity for trout
and other large-bodied fish species on the Main Stem
and to compensate for impacts on Main Stem
fisheries associated with flow changes as a result of
the Halligan Project. The fish passage will be
designed, in consultation with CPW, and to CPW’s
Research and Design Guidelines, Fish Passage and
River Structures (CPW n.d.) to provide reliable
upstream fish passage and will help to provide
additional connectivity upstream of the Fort Collins
Intake, and Fort Collins will consult with CPW on the
design of the structure. The majority of diversions
related to the Halligan Project will take place at the
Fort Collins’ Intake at Gateway Park on the Main
Stem. This diversion structure is located
approximately 0.5 mile upstream of the confluence
with the North Fork. The diversion structure currently
acts as a barrier to fish movement, preventing the
migration of fish past the structure. With this action,
Fort Collins will compensate for reduction of flows on
the Main Stem in the Exchange Reach between the
Fort Collins Intake(s) and the North Fork confluence.
Construction of this project will be completed prior to
Fort Collins beginning Halligan operations that involve exchanges on the Main Stem or on an alternate
timeline that is agreed upon between CPW and Fort Collins.
4.3.3 Compensatory Mitigation for Halligan Project Impacts on Bighorn Sheep
Fort Collins will avoid and minimize potential Project effects on bighorn sheep through the habitat
improvements and movement tracking collaring study described in Sections 4.2.3.17, 4.2.3.18, 4.2.3.19
and through construction timing restrictions described in Section 4.2.3.13. Additional construction-
related measures to avoid and minimize impacts on terrestrial wildlife, including bighorn sheep, are
described in Section 4.2.3.7. If, despite these efforts, construction of the Halligan Project causes
mortality directly, through euthanasia or otherwise, to bighorn sheep in the Lone Pine herd, Fort Collins
will offset this unavoidable impact through monetary compensation to CPW.
Fort Collins will provide monetary compensation of $7,300 per sheep to CPW for any Lone Pine herd
bighorn sheep that experience mortality during Project construction and 2 years postconstruction.
Although not all mortality experience during the construction period is anticipated to be caused by the
Project, as a conservative approach Fort Collins is willing to assume that mortalities during the
construction period and 2 years postconstruction will be compensated. Additionally, if Lone Pine herd
mortalities are observed in the 2 years following the end of construction, Fort Collins will compensate
CPW $7,300 per sheep.
CPW has concerns that the Halligan Project construction may cause Lone Pine herd sheep to change
movement patterns such that they act as a vector for disease transmission from domestic sheep to the
Figure 4-9. Fort Collins Intake at Gateway
Park
Source: City of Fort Collins
EXHIBIT A TO RESOLUTION 2025-083
Lower Poudre herd. Fort Collins will work with CPW to develop an adaptive management approach to
monitoring bighorn sheep movements to assess disease transmission, and will compensate CPW for
Lower Poudre herd bighorn sheep that were exposed to respiratory disease because of the Halligan
Project during and 2 years after construction.
4.3.4 Compensatory Mitigation for Halligan Project Impacts on Stream
Temperature
Fort Collins will commit $200,000 of funding for stream restoration efforts along the Main Stem, or
North Fork, within or near the Halligan Project Area, including the North Fork above Halligan Reservoir
to compensate for potential Project-related temperature increases. Note that this commitment is
separate from the $200,000 enhancement commitment for the North Fork described in Section 5.1.1.6;
however, these funding commitments may be combined or used independently. The restoration will be
focused on either enhancing aquatic life habitat or funding a fish passage project, or both. This money is
committed as a compensatory mitigation for unavoidable temperature impacts on the Main Stem. If the
money is used toward fish passage at the Munroe Diversion, this would allow for more natural fish
behavior and the opportunity to seek spawning habitat upstream of the diversion. Combined with the
Gateway Park Diversion fish passage, this would link more than 20 miles of upstream fish habitat year-
round. Funding of a future stream restoration project is another example of adherence to Fort Collins’
guiding principles of mitigation (refer to Section 5.1.1.6), focusing on the improvement of degraded
resources, focusing on improving whole systems and benefiting multiple (aquatic) resources, and
working in partnership with those who have common goals. Fort Collins and CPW will have final
approval authority on any use of funds and will be used for the public benefit.
4.3.5 Compensatory Mitigation for Halligan Project Impacts on Wetlands
Compensatory mitigation and monitoring for wetlands will be described in a separate mitigation plan
yet to be developed for approval by the Corps. Wetland mitigation for Halligan Project impacts may
include restoration, mitigation banking, or other measures that benefit fish and wildlife. Wetland
mitigation measures are not detailed in this FWMEP or the accompanying appendix table.
4.3.6 Special-status Species
Potential impacts of the Halligan Project on special-status species, including federally and state-listed
species, are described in Section 3.8. Fort Collins seeks to avoid and minimize any adverse impacts on
any special-status species. Halligan Project mitigation measures, such as the preservation of Roberts
Ranch (Section 4.3.1), and the numerous avoidance and minimization measures (Section 4.2) will
adequately mitigate potential Halligan Project effects on state-listed species; therefore, no additional
species-specific compensatory mitigation measures have been proposed.
4.3.6.1 Preble’s Meadow Jumping Mouse
Mitigation and monitoring of Halligan Project impacts on Preble’s are being developed in consultation
with USFWS and are described in the Halligan Water Supply Project Preble’s Meadow Jumping
Mouse Mitigation Plan (Jacobs 2022).
4.3.6.2 Ute Ladies’-tresses Orchid
Because the Ute ladies’-tresses orchid is not anticipated to occur within the Halligan Project Area (refer
to Section 3.8.3.2), Fort Collins does not propose compensatory mitigation. Avoidance and minimization
measures described in Section 4.2 will be implemented, including preconstruction botanical surveys
(Section 4.2.3.2). Furthermore, indirect benefits to potential habitat are anticipated with the
EXHIBIT A TO RESOLUTION 2025-083
implementation of wetland and riparian mitigation and enhancements associated with the Halligan
Project.
4.3.6.3 Platte River Species
Fort Collins participates in the SPWRAP, which outlines a programmatic approach for USFWS Section 7
consultation that is described in the Platte River Recovery Implementation Program. Currently,
mitigation is not expected to be needed for South Platte River depletions. If additional mitigation
measures are identified during this programmatic approach or based on USFWS consultation, they will
be incorporated into the mitigation strategy for the Halligan Project.
4.3.6.4 State-listed Species
Fort Collins seeks to avoid and minimize any adverse impacts on any state species of concern, which
were described in Section 4.2.3. Effects on state-listed and other species of concern from Fort Collins’
Proposed Action may include temporary displacement because of noise disturbance from construction
activities, transportation of people and materials, and increased human activity in the area of Halligan
Reservoir. In addition, vehicle and equipment emissions and fugitive dust may also displace state-listed
or species of concern. This displacement and disturbance of state-listed or species of concern may result
in additional stress on individuals which could lead to mortality of individuals. Some species, such as
those dependent on riparian communities, will likely experience a beneficial effect from the Halligan
Project as a result of the flow-related operational measures that will be implemented downstream of
the enlarged Halligan Reservoir.
The Halligan Project will use numerous avoidance and minimization measures described in Section 4.2,
including preconstruction bat surveys (Section 4.2.3.3) and migratory bird and raptor surveys
(Section 0). If preconstruction avian and bat surveys determine that the Project will likely adversely
affect a state-listed species avian and or bat, then Fort Collins will consult with CPW on timing,
temporary habitat modification, and other measures that may help to further avoid or minimize site-
and species-specific adverse effects. Avoidance and minimization measures, as well as the preservation
of Roberts Ranch will adequately mitigate potential Halligan Project effects on state-listed avian and bat
species and their habitats. As described in Section 4.3.1. the conservation easement on the Roberts
Ranch encompasses 4,557 acres over 10 discrete parcels (Figure 1-1). According to the CPW species
activity mapping data (CPW 2020b). In addition all 10 parcels provide vegetative communities that
support the life cycle of one or more state species including: wetlands, stream, riparian zones, rock
outcroppings, and short grass prairie communities Therefore, no additional species- habitat specific
compensatory mitigation measures other than those mentioned in the FWMEP have been proposed.
4.3.7 Recreational Resources
Anticipated Halligan Project impacts on recreational resources are described in Section 3.9.2. Because
the surface of Halligan Reservoir is not open to the public for recreational use, the Halligan Project will
not change the public’s ability to recreate on the reservoir. The LAPCR’s private access to the Halligan
Reservoir (refer to Section 3.9.1) will be minimally affected during construction and will be limited to
specific times when the reservoir level will be drawn down near the end of construction for partial or
total demolition of the existing dam.
The enlarged Halligan Reservoir will inundate approximately a 0.75-mile reach of the North Fork
upstream of the existing Halligan Reservoir, resulting in the loss of approximately 20 acres of potential
hunting lands and river fishing along a 0.4-mile stretch of this reach, as described in Section 3.9.2. Fort
Collins is proposing the following mitigation related to recreation.
EXHIBIT A TO RESOLUTION 2025-083
4.3.7.1 Reconciliation of Title Chain Confusion
As discussed in Section 3.9, in recent years, Fort Collins discovered that approximately 39 acres of land
in the eastern half of Section 29 and in the northeastern quarter of Section 32 that were thought to be
owned by CPW are owned by Fort Collins and a private party (Figure 3-4). Upper portions of the
enlarged Halligan Reservoir will be located on portions of these lands. For the most part, these lands are
surrounded by the Cherokee SWA–Middle Unit and according to CPW, these lands have been accessed
by the public for over 50 years19. Fort Collins intends to acquire these privately owned lands for the
enlarged Halligan Reservoir.
After acquiring these privately owned lands, Fort Collins will seek an agreement with CPW to convey an
easement to CPW across the Fort Collins-owned lands, approximately 39 acres (as described previously),
for public use, including river and shoreline access, provided that the surface of the enlarged reservoir
will not be opened to public access at this time. Any such agreement and conveyance will be subject to
applicable laws, including statutes applicable to CPW, and the Fort Collins Municipal Code Chapter 23
(Public Property), Article IV (Disposition of Property), Division 2 (Real Property).
As discussed in Section 3.9.3, Evaluation of Future Public Use of the Enlarged Halligan Reservoir, if,
separate from the current processes to enlarge Halligan Reservoir, the reservoir is opened to public
recreation at a point in the future, any recreation plan proposed by Fort Collins that will affect the
Cherokee SWA will be developed in conjunction with CPW and will consider impacts on fish and wildlife
habitat, including impacts on any access through the Cherokee SWA. The recreation plan will also
compensate for the resource needs for CPW to stock and manage Halligan Reservoir for public angling
access, if CPW determines it will maintain a public fishery.
4.3.7.2 Funding of Public Access Lease with Roberts Ranch
Fort Collins will contribute funding to CPW to support a lease of the Krause Field parcel of Roberts
Ranch. The Krause Field parcel is located north of Halligan Reservoir and the Cherokee SWA, as shown
on Figure 4-8. The Krause Field parcel was conserved as a part of the Roberts Ranch conservation
easement secured by Fort Collins and partners in 2003 and 2004 (refer to Section 4.3.1). CPW has been
pursuing a lease allowing primitive foot access for hunting and fishing on the Krause Field parcel. Fort
Collins understands that this lease will provide public access to over 2,200 acres of hunting and
approximately 1 mile of river access and fishing, which includes the North Fork and potentially stretches
of its tributaries, Dale Creek and Bull Creek.
Fort Collins agrees to a one-time reimbursement in the amount of $135,000 for CPW to pursue a long-
term lease (in process) of the Krause Field parcel.
4.3.7.3 Parking Area Establishment of State Wildlife Area
A primitive parking area used to provide public access to the adjacent SWA is located on Fort Collins’
property in the northeast quarter of Section 32. The parking area falls within an area previously thought
to be owned by CPW. This parking area will be inundated by the enlarged Halligan Reservoir. Fort Collins
will provide CPW with $30,000 to create a new parking area in kind on CPW land outside of the
inundation area, to provide comparable access to this general location (Figure 3-4). The new parking
area will be primitive and similar in form to the existing parking area.
19 Fort Collins is evaluating if and the extent to which the public has accessed this part of the inundation area and makes no representations on this issue.
EXHIBIT A TO RESOLUTION 2025-083
4.3.8 Instream Water Rights
The enlarged Halligan Reservoir will inundate approximately 0.75 mile of the North Fork upstream of the
current reservoir where the CWCB holds an instream flow water right, as described in Section 3.3.2.2.
Because of the additional stream flow that will be provided downstream, Fort Collins’ commitment to
protect those associated releases from Halligan Reservoir for approximately 22 miles downstream using
the Protected Mitigation Release statute (CRS Section 37-92-102[8]), and the aquatic resource
enhancements described in Section 5, no additional compensatory mitigation is proposed for impacts on
the CWCB’s instream flow water rights as part of this FWMEP.
4.4 Mitigation Costs and Schedule
Estimated costs and schedule for the mitigation components of this FWMEP follow in Appendix B.
This FWMEP includes a comprehensive description of all of Fort Collins’ planned mitigation and
enhancement measures for the Halligan Project that are related to fish and wildlife. Appendix B presents
Fort Collins’ total estimated mitigation and enhancement costs for all measures and denotes those that
CPW staff believe are attributable to the Commission’s recommendations pursuant to CRS
Section 37-60-122.2 via separate cost columns.
Appendix B includes notes describing the mitigation commitments in the table being at a summary level
and the text of this report shall take precedent over any discrepancies between the table and the
FWMEP text. Also, capitalized costs in the table are the sum of the capital cost plus any annual
operations and maintenance costs capitalized over the life of the commitment, or 50 years for those
commitments that are perpetual. In addition, some of the costs in the table are firm not-to-exceed
monetary commitments and the amounts are presented in 2022 dollars and will be increased in the
amount of the U.S. Bureau of Labor Statistics Consumer Price Index for Denver-Aurora-Lakewood from
January 1, 2023 to the date of final payment under the FWMEP obligation.
EXHIBIT A TO RESOLUTION 2025-083
5 Proposed Fish and Wildlife Enhancement Plan
This chapter constitutes the proposed enhancement plan for fish and wildlife resources in the general
Halligan Project area. Enhancement measures were developed based on comments received on the
DEIS, discussions with CPW staff, and discussions with other Halligan Project stakeholders. The
enhancements described in this chapter will improve both existing and future anticipated conditions of
the aquatic and terrestrial environment without regard to causation. These measures integrate with
Fort Collins’ vision and overarching goals for the Halligan Project and demonstrate Fort Collins’ ongoing
commitment to improve existing conditions in the Poudre River watershed. Chapter 4 of this FWMEP
describes the approach used to identify and develop mitigation and enhancement measures.
This enhancement plan updates, builds upon, and/or replaces some of the measures presented in the
draft CMP (City of Fort Collins 2019c) released with the DEIS (Corps 2019). The measures described in
this enhancement plan have been updated since the development of the CMP. Some enhancement
measures are similar to or directly replace measures described in the CMP. New enhancement measures
have also been developed and described herein that were not presented in the draft CMP. All measures
included in this FWMEP are summarized in the table contained in Appendix B.
5.1 Enhancement Measures
Fort Collins is committed to incorporating the voluntary enhancements described in the following
sections into the Halligan Project. These enhancement measures are not required to meet regulatory
mitigation requirements, and are above and beyond the measures presented in Chapter 4 that Fort
Collins will undertake to avoid, minimize, or compensate for impacts resulting from the Halligan Project.
5.1.1 Aquatic Resources Enhancements
5.1.1.1 Temporary Environmental Pool
Between the time that Halligan Reservoir is enlarged and the time when Fort Collins grows into its
future demand levels associated with the Halligan Project, Fort Collins will dedicate an annually variable
storage volume in the enlarged Halligan Reservoir to release for environmental benefits downstream.
This annually variable volume of water dedicated for environmental benefits is referred to as the
temporary environmental pool (TEP).
The purpose of the TEP is to enhance the environmental benefit, or functional lift, of the flow-related
operational measures described in Section 4.2.1. The primary objective of the TEP is to positively affect
stream health in the North Fork from the replacement Halligan Dam to Seaman Reservoir. In general,
the TEP will be used to benefit whole stream health, with the ability to focus on specific river functions,
or single-species management in select years. Use of the TEP will be informed by first principles of river
ecology.
Operation of the Temporary Environmental Pool
Fort Collins will determine the volume of water available for the TEP each year. Volumes in the range of
500 to 1,000 acre-feet are expected to be available; however, the actual volume available could increase
or decrease after information is gained from the first several years of operation of the enlarged Halligan
Reservoir. The annual volume of water available is expected to be reduced or eliminated over time, as
water demand for Fort Collins’ water customers increases. The TEP is currently anticipated to be
operated through 2065, although it could occur sooner or later than that depending on when Fort
Collins grows into its future demand levels associated with the Halligan Project.
EXHIBIT A TO RESOLUTION 2025-083
Fort Collins will determine the volume of water available to be dedicated on an annual basis based on
water demand and water supply outlook. The volume and targeted window for releases will be
determined before July 1 each year. The window for releases will typically be from July 1 to the
following April 30. The ramping rate limitations described previously will apply to such releases. The
releases will be operated and used pursuant to Fort Collins’ water rights decrees.
Releases from the TEP will be made from the enlarged Halligan Reservoir and conveyed down the North
Fork. The TEP releases will be made only if Fort Collins can place them to decreed beneficial uses for the
releases under Fort Collins’ water rights. Fort Collins will determine the water right(s) to which the TEP
releases are attributed. This may include uses further downstream on the Poudre River (for example, to
Rigden Reservoir) that could potentially provide secondary benefits to the river. Fort Collins will not
redivert the TEP releases until after they have reached the confluence with the Main Stem.
Decisions regarding the volume of water allocated each year will be made by Fort Collins. The primary
stakeholders for the TEP will be Fort Collins and CPW; however, a small group of technical advisers,
resource experts, and/or other stakeholders may be developed to guide decisions related to the best
use of the TEP. The best use of this water will be determined based on decreed beneficial uses of the
water rights and current conditions at that point in time and the greatest ecological concerns or issues,
with one of the priorities being management of small-bodied native fish species downstream of Halligan
Reservoir. Operational targets for use of the TEP could be set for several years at a time to address
multiple ecological priorities. If CPW or another entity identifies additional water rights for storage in
the enlarged Halligan Reservoir and allocated to the TEP, Fort Collins will consider specific proposals in
good faith, after all required permits have been issued for the Halligan Project.
Protection of the Temporary Environmental Pool Releases
NPIC cannot divert the TEP releases into the North Poudre Canal pursuant to an existing agreement with
Fort Collins. Additionally, Fort Collins will attempt to protect the TEP releases from Halligan Reservoir to
Seaman Reservoir using the Protected Mitigation Release statute (CRS Section 37-92-102[8]) in the same
manner as described here for the Winter Releases Plan (Section 4.2.1.1). Fort Collins will undertake a
good faith effort to protect the TEP releases under the Protected Mitigation Release statute. However,
success is not guaranteed because it will depend on factors outside of Fort Collins’ control.
Curtailment of the Temporary Environmental Pool
Fort Collins may need to curtail or stop TEP releases in the event of maintenance, drought, or
emergency situations. Fort Collins may also modify the release schedule if another water resource need
develops within the Fort Collins’ water system. As such, the storage volume of the TEP may vary
significantly each year, and it will not be operated during water supply shortages (refer to
Section 4.2.1.7). Again, the annual volume of water available is expected to be reduced or eliminated
over time, as water demand for Fort Collins’ water customers increases.
Fort Collins may need to curtail or stop TEP releases in the event of maintenance, drought, or
emergency situations. Fort Collins may also modify the release schedule if another water resource need
develops within the Fort Collins’ water system. As such, the storage volume of the TEP may vary
significantly each year, and it will not be operated during water supply shortages (refer to
Section 4.2.1.7). Again, the annual volume of water available is expected to be reduced or eliminated
over time, as water demand for Fort Collins’ water customers increases.
EXHIBIT A TO RESOLUTION 2025-083
5.1.1.2 Joint Operations
Fort Collins will continue to entertain opportunities for operational synergies with other managed water
deliveries in the Poudre River watershed in order to potentially provide targeted benefits to the
watershed. For example, Fort Collins might consider a temporary (that is, 1 year) water trade with an
irrigation company or another municipal water provider that temporarily increases releases from the
Halligan enlargement in exchange for other water sources that can be used by Fort Collins. Joint
operations will not compromise the commitments in the FWMEP. Fort Collins may consider engaging
CPW in these discussions when appropriate.
5.1.1.3 Fish Passage at the Reconstructed North Poudre Canal Diversion
The North Poudre Canal Diversion (Figure 5-1) is
located in Phantom Canyon, approximately 6 river
miles downstream of Halligan Reservoir on the
North Fork. The structure currently acts as a
barrier to upstream fish passage, preventing the
migration of fish past the structure. As part of the
Halligan Project, Fort Collins will reconstruct the
North Poudre Canal Diversion so that Fort Collins’
releases (refer to Section 4.2.1) can be bypassed
by that structure and remain in the North Fork. To
provide increased connectivity for small-bodied
native species and trout in the North Fork, Fort
Collins will incorporate fish passage into or around
the reconstructed North Poudre Canal Diversion, in
the form of a fish ladder, bypass channel, or other
infrastructure. Fish passage will be designed, in
consultation with CPW, and to CPW’s Research
and Design Guidelines, Fish Passage and River Structures (CPW n.d.) to provide reliable fish passage at
the North Poudre Canal Diversion and connect an extensive reach of the North Fork. Fish passage
construction will happen concurrently with reconstruction of the North Poudre Canal Diversion, in
accordance with the timeline listed in Figure 4-7, will be completed by the time Fort Collins begins
storing water in the enlarge Halligan Reservoir or an alternate timeline that is agreed upon between
CPW and Fort Collins.
5.1.1.4 Channel Improvements and Modification of the Calloway Diversion
The Calloway Diversion (Figure 5-2) is located on the North Fork at the mouth of Phantom Canyon,
approximately 7.5 river miles downstream of Halligan Reservoir. The diversion is no longer used.
Although water passes the structure, it acts as a barrier to fish passage, preventing the migration of fish
past the structure. As an additional measure to further enhance the fisheries of small-bodied native fish
on the North Fork, Fort Collins will seek to
Figure 5-1. North Poudre Canal Diversion
Structure
Source: Jacobs
EXHIBIT A TO RESOLUTION 2025-083
modify and/or partially remove the diversion
structure in collaboration and agreement with the
landowners, CPW, and other stakeholders.
Proposed plans should follow CPW’s Research and
Design Guidelines, Fish Passage and River
Structures (CPW n.d.).
The current concept that Fort Collins has
developed for the area around the Calloway
Diversion, in collaboration with landowners, CPW,
and other stakeholders, includes removal of the
center portion of the structure, while leaving the
sidewalls of the structure in place. This
modification will allow for full river connectivity
while maintaining a portion of the historical
structure. Over time, this portion of the channel
will heal and be re-established to a more natural
condition while enhancing river connectivity for aquatic organisms, including macroinvertebrates, small-
bodied native fish, and trout. This action is also considered a voluntary enhancement measure for North
Fork temperature. The action will remove an existing large, sediment-trapping pool that increases
residence time and warming at low flow rates. Removal of the center portion of the existing diversion
will also remove the barrier to fish passage, allowing more natural fish behavior, including the potential
to seek thermal refuge upstream. Further, the channel improvements will result in a more natural
thalweg, including pools that can serve as areas of thermal refuge in times of low flow and adult holding
and overwinter habitat. Fort Collins will pursue an agreement in good faith with the landowners and
other stakeholders to complete this Project. This project will be constructed in accordance with the
timeline listed in Figure 4-7 and will be completed by the time Fort Collins begins storing water in the
Halligan Reservoir Expansion or an alternate timeline that is agreed upon between CPW and Fort Collins.
If Fort Collins is unable to come to an agreement with the landowners to complete channel
improvements and modifications of the Calloway Diversion within the timeline that aligns with the
reconstruction of the North Poudre Canal Diversion discussed in Section 5.1.1.3, Fort Collins will
coordinate with CPW and the landowners to discuss an alternative timeline to avoid or minimize impacts
to bighorn sheep as discussed in Sections 4.2.3.13, 4.2.3.17, and 4.2.3.19.
Terrestrial Improvements
Improvements at the Calloway Diversion Structure will have the largest impact on aquatic habitat;
however, improvements will also benefit terrestrial species, specifically Preble’s. USFWS considers the
Calloway Diversion to be a habitat filter to Preble’s movement. Removing the diversion will reconnect
Preble’s habitat.
5.1.1.5 Ramping Rate Limitations for NPIC’s Pool in an Enlarged Halligan Reservoir
The ramping rate limitations described in Section 4.2.1.4 apply only to Fort Collins’ operation of its
portion of the enlarged Halligan Reservoir; they do not apply to operation of NPIC’s portion of the
reservoir. Therefore, Fort Collins will commit to making a good faith effort to reach an agreement with
NPIC to adhere to the same ramping rate limitations. Previous discussions with NPIC indicate that it
would prefer to explore any such commitments after the enlarged reservoir is operational for several
years. At that time, Fort Collins will re-engage in discussions with NPIC about ramping their diversions
and releases to match those rates Fort Collins has committed to.
Figure 5-2. Calloway Diversion Structure
Source: Jacobs
EXHIBIT A TO RESOLUTION 2025-083
5.1.1.6 North Fork Stream Restoration
Fort Collins will commit $200,000 of funding for stream restoration efforts along the North Fork, or Main
Stem, within or near the Halligan Project Area, including the North Fork above Halligan Reservoir. The
restoration will be focused on either enhancing habitat for small-bodied native fish or salmonids.
Funding a future stream restoration project is another example of adherence to Fort Collins’ guiding
principles of mitigation (refer to Section 4), such as focusing on the improvement of degraded resources,
focusing on improving whole systems and benefiting multiple (aquatic) resources, and working in
partnership with those who have common goals. Note that this commitment is separate from the
$200,000 mitigation commitment for the Main Stem described in Section 4.3.4; these funds may be
combined or used independently. Fort Collins and CPW will have final approval authority on any use of
funds, and will be used for the public benefit.
5.2 Surface Water Quality Enhancement
5.2.1 Sediment-related Operational Measures
In addition to the Peak Flow Bypass Program described in Section 4.2.1.5, and the sediment
management plan described in Section 4.2.4, the following sediment-related operational measures are
planned for Halligan Reservoir to avoid future adverse sediment release events.
5.2.1.1 Bottom Release from Halligan Reservoir when Spilling
Water will be released from Halligan Reservoir through the bottom outlets at times when the reservoir
is spilling over the dam. This should allow for reduced retention of sediment in Halligan Reservoir,
allowing for appropriate sediment transport downstream to the North Fork (as directed by the total
maximum daily load [TMDL]). Avoiding buildup of sediment behind the dam should, in part, help avoid
an adverse sediment release event like the one that occurred because of operations in 1996.
This measure is also considered a voluntary enhancement in terms of river temperature for its parallel
benefits in reducing the risk of thermal shock below the Halligan Reservoir dam. As described in
Section 3.4.2, thermal shock can occur below the Halligan Reservoir dam under current Halligan
Reservoir dam operations. The Halligan Project has an inherent benefit of reducing the current
frequency of thermal shock below Halligan Reservoir dam because no spilling is anticipated (per DEIS
flow modeling) to occur in summer or fall months (that is, at times when the reservoir is thermally
stratified). Bottom releases during spilling would provide further enhancement in terms of further
reducing the risk of thermal shock because such releases would serve to blend top and bottom
temperatures, minimizing the sharp temperature change in releases, in the unanticipated event that the
reservoir does spill at a time of thermal stratification with the Halligan Project.
5.2.2 Passive Aeration in Outlet Structure
Fort Collins will incorporate design measures for the replacement Halligan Dam that include passive
physical aeration. This will increase DO concentrations in water released to the North Fork, enhancing
conditions for aquatic life immediately below the reservoir. As described in Section 3.4.2.3, DO
concentrations at levels of concern to aquatic life are not anticipated below Halligan Reservoir;
however, there is the potential for small decreases in DO in the Halligan Reservoir hypolimnion in the
latter part of the summer. Because adverse impacts on aquatic life are not anticipated in terms of
oxygen below Halligan Reservoir, inclusion of passive aeration in the outlet structure is considered to be
a voluntary enhancement, as opposed to mitigation. Design measures are being evaluated that would
increase DO include an updated stilling basin, a stepped spillway, and a turbulent discharge area with
EXHIBIT A TO RESOLUTION 2025-083
energy dissipation. This aeration will be applied to releases from both Fort Collins’ and NPIC’s portion of
the enlarged Halligan Reservoir.
5.2.3 Terrestrial Resources Enhancements
5.2.3.1 Prohibition of Domestic Sheep and Goat Grazing on City Owned Lands Near
Halligan Reservoir
An existing and ongoing challenge in CPW’s management of the Lone Pine bighorn sheep herd is the
known proximity of bighorn sheep to domestic sheep grazing (CPW 2021b). Several land managers
within the Lone Pine herd-occupied range along or near key components of the Halligan Project use
domestic sheep to control larkspur (Delphinium species), which are toxic to cattle. Although domestic
sheep can be an effective vegetation management tool, this practice increases the chances of
commingling between the Lone Pine herd and domestic sheep. The greatest concern of such
commingling is the transmission of deadly pathogens between domestic sheep and goat populations
and the Lone Pine herd. Therefore, to help reduce the long-term risk of disease transmission, and as
soon as this FWMEP is approved, Fort Collins will:
• Permanently stop grazing domestic sheep or goats for weed control or other purposes on any Fort
Collins-owned lands around Halligan Reservoir
• Will not enter into grazing leases that would authorize others to graze domestic sheep or goats on
any Fort Collins-owned lands around Halligan Reservoir
• Will not grant licenses or convey easements authorizing domestic sheep or goats to graze on any
Fort Collins-owned lands around Halligan Reservoir
5.2.3.2 Advocate for Cessation of Domestic Sheep and Goat Grazing on Private Lands
Near Halligan Reservoir
Landowners near the Halligan Project Area periodically allow domestic sheep and goat grazing on their
property to control larkspur, which are toxic to cattle and horses. Comingling of domestic sheep and
goats with bighorn sheep is linked to disease transmission to bighorn sheep, which can result in bighorn
sheep mortality. Fort Collins will engage with local landowners to advocate for both the temporary
cessation of domestic sheep and goat grazing during construction, as well as for the permanent
cessation of domestic sheep and goat grazing near the Halligan Project Area. Ceasing domestic sheep
and goat grazing on private property around the Halligan Project Area will avoid the potential for
disease transmission from domestic sheep and goats to bighorn sheep.
5.3 Fort Collins Ecological Resource Monitoring
5.3.1 Streamflow Monitoring
As part of Halligan Project operations, Fort Collins has already installed one of two new North Fork
streamflow gages associated with the Halligan Project. The first gage, located above the future inlet of
the enlarged Halligan Reservoir, was installed by Fort Collins in fall 2020 in coordination with the United
States Geological Survey. An existing stream gage is located below the Halligan Dam that will remain in
the future. The second gage will be installed by Fort Collins at or below the bypass structure for the
reconstructed North Poudre Canal Diversion to monitor streamflow and inform North Poudre Canal
Diversion and Halligan Reservoir operations. In addition, Fort Collins will also rely on the existing
Livermore gage located where the North Fork crosses West County Road 74E. Streamflow monitoring
data will enhance the existing dataset that is available for public use and will also be used by Fort Collins
to help inform operational decisions for the enlarged Halligan Reservoir.
EXHIBIT A TO RESOLUTION 2025-083
5.3.2 Sediment, Macroinvertebrates, and Water Quality Monitoring
Sampling for sediment (percent fines and salmonid spawning habitat) and macroinvertebrates (TIVSED),
downstream of Halligan Reservoir will be conducted following protocols in WQCD Policy 98-1 (in
agreement with Policy Statement 10-1, Aquatic Life Use Attainment, Methodology to Determine Use
Attainment for Rivers and Streams). This sediment sampling will continue for a period of 5 years
following the build out of Halligan Project operations, after which time the need to continue sampling
will be reconsidered in coordination with CPW and WQCD. This sampling will help monitor sediment
relative to standards and identify any new impairment or worsening conditions. This information can be
used to determine appropriate response actions per the sediment management plan (Section 5.2.1.1),
as needed.
Additionally, real-time oxygen and temperature data from multiple elevations in Halligan Reservoir
during summer months will be needed to support operational decision-making for the MLOW, if an
MLOW is installed (as discussed in Section 4.2.2.1). Real-time oxygen and temperature data from
multiple elevations in Halligan Reservoir during summer months would be used to help manage water
quality of releases to the North Fork with an MLOW. As such, this monitoring will be conducted as a
critical component of the MLOW mitigation element, if an MLOW is installed.
Fort Collins will also monitor iron immediately below the enlarged reservoir for 5 years to determine if
the flushing event (described in Section 4.2.1.6) is effective and/or necessary. This monitoring will
consist of visual checks for iron deposition on sediment in the vicinity of the NBH sampling station (and
photographic records of any observed deposition) as well as continued sampling at NBH for dissolved
and total iron. However, if it is determined at the end of the first 5 flushing events (in consultation with
CPW) that this operation is no longer needed, then the releases and special monitoring (observations of
iron deposition) will end.
5.3.3 Bighorn Sheep Collaring Study
Collaring and tracking of the Lone Pine herd will be conducted before, during, and after the Halligan
Project construction as part of the avoidance and minimization mitigation measures described in
Section 4.2.3.18 and the compensatory mitigation measure described in Section 4.3.3.
5.4 Enhancement Costs and Schedule
Estimated costs and schedule for the mitigation components of this FWMEP follow in Appendix B.
This FWMEP includes a comprehensive description of all of Fort Collins’ planned mitigation and
enhancement measures for the Halligan Project that are related to fish and wildlife. Appendix B presents
Fort Collins’ total estimated mitigation and enhancement costs for all measures and denotes those that
CPW staff believe are attributable to the Commission’s recommendations pursuant to CRS
Section 37-60-122.2 via separate cost columns.
Appendix B includes notes describing the mitigation commitments in the table being at a summary level
and the text of this report shall take precedent over any discrepancies between the table and the
FWMEP text. Also, capitalized costs in the table are the sum of the capital cost plus any annual
operations and maintenance costs capitalized over the life of the commitment, or 50 years for those
commitments that are perpetual. In addition, some of the costs in the table are firm not-to-exceed
monetary commitments and the amounts are presented in 2022 dollars and will be increased in the
amount of the U.S. Bureau of Labor Statistics Consumer Price Index for Denver-Aurora-Lakewood from
January 1, 2023 to the date of final payment under the FWMEP obligation.
EXHIBIT A TO RESOLUTION 2025-083
6 References
Armstrong, D. M., J. P. Fitzgerald, and C. A. Meaney. 2011. Mammals of Colorado. University Press of
Colorado. Denver, Colorado.
Armstrong, Karlyn. 2020. Memorandum from Water Resources Engineer and Water Project Mitigation
Coordinator to the Colorado Parks and Wildlife Commissioners; Overview of Fish and Wildlife
Mitigation Plan Process. March 5.
Bartholow, J. M. 1991. A Modeling Assessment of the Thermal Regime for an Urban Sport Fishery.
Environmental Management. Vol. 15, No. 6. pp 833–845.
Battige, K. 2018. 8/23/2018: North Fork Poudre River Below Seaman Reservoir Fish Kill Investigation.
Report prepared by CPW Aquatic Biologist.
Beardsley, M., J. B. Johnson, and J. Doran. 2015. FACStream 1.0: Functional Assessment of Colorado
Streams. Report submitted to U.S. Environmental Protection Agency.
https://www.fcgov.com/poudrereportcard/pdf/river-health-assessment-methods2019.pdf.
Bestgen, K., N. L. Poff, D. Baker, B. Bledsoe, D. Merritt, M. Lorie, G. Auble, J. Sanderson, and
B. Kondratieff. 2019. “Designing flows to enhance ecosystem functioning in heavily altered
rivers.” Ecological Applications. Vol. 30, Issue 1. Ecological Society of America: Wiley Periodicals,
Inc., Washington, D.C. September 18. https://doi.org/10.1002/eap.2005.
Cadmus, P., S. F. Brinkman, and M. K. May. 2018. “Chronic Toxicity of Ferric Iron for North American
Aquatic Organisms: Derivation of a Chronic Water Quality Criterion Using Single Species and
Mesocosm Data.” Archives of Environmental Contamination and Toxicology. ISSN 0090-4341.
Vol, 74, No. 4. May.
CDM Smith and DiNatale Water Consultants (CDM and DiNatale). 2013. Northern Integrated Supply
Project Environmental Impact Statement Common Technical Platform Hydrologic Modeling
Report. Prepared for the U.S. Army Corps of Engineers, Omaha District.
CDM Smith (CDM). 2017. Draft Surface Water Quality Technical Report for the Halligan Water Supply
Project Environmental Impact Statement. October.
Colorado Department of Public Health and Environment and Colorado Department of Natural Resources
(CDPHE and CDNR). 2017. Memorandum of Understanding for Water Supply Projects between
the Colorado Department of Health and Environment and the Colorado Department of Natural
Resources. June.
Colorado Division of Water Resources (DWR). 2016. General Administrative Guidelines for Reservoirs.
February. Originally issued October 2011.
https://dnrweblink.state.co.us/dwr/DocView.aspx?id=3579805&dbid=0&cr=1.
City of Fort Collins. n.d. Climate Action Plan. Accessed 2021. https://www.fcgov.com/climateaction/.
City of Fort Collins. 2011. Cache La Poudre River Natural Areas Management Plan Update. June 10.
https://www.fcgov.com/naturalareas/pdf/poudre-management-plan2011.pdf.
City of Fort Collins. 2014. Poudre River Downtown Master Plan. October. https://www.fcgov.com/
poudre-downtown/pdf/final-plan.pdf.
City of Fort Collins. 2015a. City of Fort Collins 2015 Water Efficiency Plan. https://www.fcgov.com/
utilities/img/site_specific/uploads/WEP_2015-17_FullDraft_NoWaterMark_v9.pdf?1640792992.
EXHIBIT A TO RESOLUTION 2025-083
City of Fort Collins. 2015b. Cache la Poudre River: River Health Assessment Framework. August 26.
https://www.fcgov.com/naturalareas/pdf/river-health-report-final-appendix.pdf.
City of Fort Collins. 2017. State of the Poudre: A River Health Assessment. May 24.
https://www.fcgov.com/poudrereportcard/pdf/sopr2016.pdf.
City of Fort Collins. 2019a. Fort Collins Utilities Water Supply Vulnerability Study Draft Report. June.
City of Fort Collins. 2019b. Cache la Poudre River: River Health Assessment Framework, 2019 Methods
and Applications. https://www.fcgov.com/poudrereportcard/pdf/river-health-assessment-
methods2019.pdf?1595449775.
City of Fort Collins. 2019c. Halligan Water Supply Project Conceptual Mitigation Plan. Draft Report.
October. https://usace.contentdm.oclc.org/digital/collection/p16021coll7/id/12793.
City of Fort Collins. 2020a. 2020 Strategic Plan. https://www.fcgov.com/citymanager/files/20-22326-
2020-strategic-plan-document_final.pdf.
City of Fort Collins. 2020b. Water Shortage Action Plan. As adopted by Fort Collins City Council April
2020, as referenced in Section 26-167(a) of the Code of Fort Collins. https://www.fcgov.com/
utilities/img/site_specific/uploads/final-wsap-effective-may-1-2020.pdf?1604940044.
City of Fort Collins. 2021a. 2020 Water Conservation Annual Report. https://www.fcgov.com/utilities/
img/site_specific/uploads/21-23060-water-conservation-annual-report-v5.pdf?1621375599.
City of Fort Collins. 2021b. Draft Cameron Peak Wildfire Water Quality Monitoring Recovery Plan.
April 7. https://www.fcgov.com/utilities/img/site_specific/uploads/cameron-peak-water-
quality-monitoring-recovery-plan.pdf?1650308076.
Colorado Natural Heritage Program. 2015. Query results for Element Occurrences within two-mile buffer
of the Halligan EIS project alternatives.
Colorado Parks and Wildlife (CPW). n.d. Research and Design Guidelines, Fish Passage at River
Structures. https://cpw.state.co.us/Documents/Research/Aquatic/pdf/Fish-Passage-River-
Structures_Research-Guidelines.pdf.
Colorado Parks and Wildlife (CPW). 2015. State Wildlife Action Plan. https://cpw.state.co.us/aboutus/
Pages/StateWildlifeActionPlan.aspx.
Colorado Parks and Wildlife (CPW). 2018. North Fork Poudre River–Phantom Canyon: 2017 Fishery
Sampling Survey Summary.
Colorado Parks and Wildlife (CPW). 2020a. North Fork Poudre River Fish Survey Sampling Data.
Unpublished data for 1960 through 2020.
Colorado Parks and Wildlife (CPW). 2020b. CPW Public SAM (Species Activity Maps) Data. December 8.
CPW GIS Unit. Colorado Parks and Wildlife - Species Data 2020. Bald Eagle.
https://cpw.state.co.us/learn/Pages/Maps.aspx.
Colorado Parks and Wildlife (CPW). 2021a. January 11, 2021 Memorandum: Halligan Reservoir
Expansion Project Bighorn Sheep Impacts and Mitigation.
Colorado Parks and Wildlife (CPW). 2021b. Draft Halligan Reservoir Mitigation Plan for S40: Lone Pine
Rocky Mountain Bighorn Sheep Herd. September 15.
Colorado Parks and Wildlife (CPW). n.d. “Species Profiles.” http://cpw.state.co.us/learn/Pages/
SpeciesProfiles.aspx.
EXHIBIT A TO RESOLUTION 2025-083
Colorado State University (CSU). 2020. Poudre Runs Through It Study/Action Work Group. A Guiding
Document. Colorado State University, Colorado Water Center, Fort Collins, Colorado. Revised
September 28. https://watercenter.colostate.edu/prti/.
Colorado Water Conservation Board (CWCB). 1984. Fish and Wildlife Resources. Colorado Revised
Statute Title 37, Section 37-60-122.2. Colorado Department of Natural Resources, Colorado
Water Conservation Board.
Colorado Water Conservation Board (CWCB) n.d. Rules Concerning the Colorado Instream Flow and
Natural Lake Level Program. Rule 7. Colorado Revised Statute Title 2, Section 408-2. Colorado
Department of Natural Resources, Colorado Water Conservation Board.
GEI Consultants, Inc. (GEI). 2016. Aquatic Biological Resources North Fork Cache La Poudre River for the
Halligan Water Supply Project Environmental Impact Statement. Final draft, Baseline Technical
Report.
GEI Consultants, Inc. (GEI). 2018. Draft Aquatic Biological Resources Effects Technical Report for the
Halligan Water Supply Project Environmental Impact Statement. October.
GEI Consultants, Inc. (GEI). 2019a. Baseline Technical Report Aquatic Biological Resources North Fork
Cache La Poudre River. Prepared for the U.S. Army Corps of Engineers, Omaha District. May.
GEI Consultants, Inc. (GEI). 2019b. Aquatic Biological Resources Effects Technical Report for the Halligan
Water Supply Project Environmental Impact Statement. Prepared for the U.S. Army Corps of
Engineers, Omaha District. November.
Harman, W., R. Starr, M. Carter, K. Tweedy, M. Clemmons, K. Suggs, C. Miller. 2012. A Function-Based
Framework for Stream Assessment and Restoration Projects. U.S. Environmental Protection
Agency, Office of Wetlands, Oceans, and Watersheds, Washington, DC. EPA 843-K-12-006.
Hawley, C., J. M. Boyer, T. Adams, A. Stone, and L. Daugherty. 2014. Stream Temperature and Dissolved
Oxygen Analysis for NISP Supplemental Draft EIS. Summary of Current Conditions and
Qualitative Anticipated Effects of NISP Alternatives. Prepared by Hydros Consulting for ERO
Resources Corporation. December 12.
Hydros Consulting Inc. (Hydros). 2015. Water-Quality Modeling of the Cache la Poudre River – Concepts,
Approach, and Scope of Work to Support Development of the NISP Final EIS. Prepared for ERO
Resources Corporation by Hydros Consulting. June 25.
Hydros Consulting Inc. (Hydros). 2020. Halligan Reservoir Water-Quality Model: Conceptual
Understanding of Water-Quality Dynamics. Technical Memorandum from J.M. Boyer (Hydros) to
E. Dornfest (City of Fort Collins). March 17.
Hydros Consulting Inc. (Hydros). 2021a. Background Conceptual Understanding to Support Additional
Stream Modeling for Halligan 401 Certification Application. Technical Memorandum from C.
Hawley (Hydros) to E. Dornfest (City of Fort Collins). December 20.
Hydros Consulting Inc. (Hydros). 2021b. Halligan Water Supply Project 401 Certification Analysis –
North Fork and Seaman Reservoir Conceptual Understanding and Recommended Approaches
for Water Quality. Technical Memorandum from K. Bierlein (Hydros) to E. Dornfest (City of
Fort Collins). December 21.
Hydros. 2021c. Halligan Water Supply Project 401 Certification Analysis – Poudre River Water-Quality
Conceptual Understanding and Approach. Technical Memorandum from K. Bierlein (Hydros)
to E. Dornfest (City of Fort Collins). December 22.
EXHIBIT A TO RESOLUTION 2025-083
Hydros Consulting Inc. (Hydros). 2021d. Understanding of River Temperature in the North Fork and
Poudre River Main Stem. Technical Memorandum from C. Hawley (Hydros) to E. Dornfest (City
of Fort Collins). December 23.
Hydros Consulting Inc. (Hydros). 2022a. HWSP FWMEP Development – Responses to CPW Questions.
Technical Memo to M. May (CPW) from C. Hawley (Hydros Consulting Inc.). March 17, 2022.
Hydros. 2022b. HWSP Effects on Proportional Contribution of NF Flow to Poudre Mainstem. Technical
Memo to A. Conovitz (City of Fort Collins) from T. Adams (Hydros Consulting Inc.). August 17.
Hydros Consulting Inc. (Hydros). 2022c. HWSP FWMEP Development – Documentation of Key
Discussions with CPW. Technical Memo to M. May (CPW) from C. Hawley (Hydros Consulting
Inc.). December 15, 2022.
Interagency Grizzly Bear Committee Public Lands Wildlife Linkage Task Force. 2004. Identifying and
Managing Wildlife Linkage Approach Areas on Public Lands; A Report to the Interagency Grizzly
Bear Committee. June 17.
Interagency Visitor Use Management Council. 2016. Visitor Use Management Framework, A Guide to
Providing Sustainable Outdoor Recreation. Edition One. July.
Jacobs. 2021. Preconstruction Survey Memo (Birds, Bats, and Orchids). November 29.
Jacobs. 2022. Halligan Water Supply Project Preble’s Meadow Jumping Mouse Mitigation Plan. April.
JW Associates, Inc. 2017. Upper Poudre Resilience Watershed Plan Final. Coalition for the Poudre River
Watershed. January. https://www.poudrewatershed.org/plan/.
Larimer County Planning Department. 2021. Land Use Code. https://www.larimer.org/planning/land-
use-code.
Law Insider. n.d. “Ecological function definition.” https://www.lawinsider.com/dictionary/ecological-
function.
Lorie, M., J. Sanderson, B. Werick. 2010. Halligan-Seaman Shared Vision Planning; An Experiment in
Collaborating for Regulatory Decisions. Unpublished report. July 9.
http://www.conservationgateway.org/ConservationByGeography/NorthAmerica/UnitedStates/
Colorado/Documents/Lorie%20et%20al.%202010%20Halligan_Seaman_Shared_Vision_Planning
_Report_Jul_12_2010.pdf.
Miller Ecological Consultants (Miller). 2009. Aquatic Resource Existing Conditions Halligan-Seaman
Water Management Project. Prepared for the City of Fort Collins and the City of Greeley.
Miller Ecological Consultants, Inc. (Miller). 2017. Comparison of North Fork Cache La Poudre aquatic
habitat between baseline and proposed the Halligan Project operations. Memorandum to City of
Fort Collins. October 20.
Natural Resources Conservation Service (NRCS). n.d. Black Mountain Snotel Site, United States
Department of Agriculture, NRCS National Water and Climate Center. Accessed January 2, 2021.
https://wcc.sc.egov.usda.gov/nwcc/site?sitenum=1161.
Pioneer Environmental Services (Pioneer). 2016a. Aquatic Resource Inventory Report. Draft. Halligan
Reservoir, Larimer County, Colorado. July 29.
Pioneer Environmental Services (Pioneer). 2016b. Aquatic Resources Associated with the New Proposed
Ordinary High Water Mark. Supplement to the ARI Report for the Halligan Reservoir
(Appendix E). July 28.
EXHIBIT A TO RESOLUTION 2025-083
Pioneer Environmental Services (Pioneer). 2017a. Revised Report, Impacts on Aquatic Biological
Resources for the Halligan Water Supply Project. November 3.
Pioneer Environmental Services (Pioneer). 2017b. Revised Report, Impacts on Aquatic Species of Concern
and Water Based Recreation for the Halligan Water Supply Project. November 3.
Risenhoover, K. L. and J. A. Bailey. 1985. Foraging ecology of mountain sheep:
Implications for habitat management. Journal of Wildlife Management. Vol. 49, No. 3.
pp. 797-804.
TetraTech. 2018. Milton Seaman Reservoir Hydrodynamic and Water Quality Model. Revised draft.
Prepared for the U.S. Army Corps of Engineers and the City of Greeley, Colorado. April.
The Nature Conservancy (TNC). 2008. Environmental Flows for the North Fork of the Cache la Poudre
River. Provided as Appendix 3 of the Halligan-Seaman Shared Vision Planning document.
January 4.
Thode, Zach, Land Manager, Roberts Ranch. 2021. Personal communication (telephone conversation)
with Alice Conovitz, City of Fort Collins Utilities Permit Coordinator. December 3.
U.S. Army Corps of Engineers (Corps). 2019. Environmental Impact Statement Halligan Water Supply
Project. Draft. Prepared by U.S. Army Corps of Engineers, Omaha District, Omaha, Nebraska.
November. https://www.nwo.usace.army.mil/Missions/Regulatory-Program/Colorado/EIS-
Halligan/.
U.S. Army Corps of Engineers (Corps). 2020. Colorado Mitigation Procedures. Version 2.0. Prepared by
U.S. Army Corps of Engineers, Albuquerque, Omaha, and Sacramento Districts.
https://www.nwo.usace.army.mil/Missions/Regulatory-Program/Colorado/Mitigation/.
U.S. Environmental Protection Agency (EPA). 1990. Memorandum of Agreement between the
Environmental Protection Agency and the Department of the Army Concerning the
Determination of Mitigation Under the Clean Water Act Section 404(b)(1) Guidelines.
https://www.epa.gov/cwa-404/memorandum-agreement-regarding-mitigation-under-cwa-
section-404b1-guidelines-text.
U.S. Environmental Protection Agency (EPA) and U.S. Army Corps of Engineers (Corps). 2008.
Compensatory Mitigation for Losses of Aquatic Resources. Final Rule. Code of Federal
Regulations Title 33, Parts 325 and 332. Published in the Federal Register on April 10, 2008.
https://www.epa.gov/cwa-404/compensatory-mitigation-losses-aquatic-resources-final-rule.
U.S. Fish and Wildlife Service (USFWS). 2018. Recovery Plan Preble’s Meadow Jumping Mouse (Zapus
hudsonius preblei). August 28. https://www.fws.gov/mountain-prairie/es/species/mammals/
preble/RECOVERY%20PLAN/Sept2018FinalRecoveryPlan.pdf.
U.S. Fish and Wildlife Service (USFWS). 2019. Endangered and Threatened Wildlife and Plants; Removing
Oenothera coloradensis (Colorado Butterfly Plant) From the Federal List of Endangered and
Threatened Plants. 84 FR 59570.
https://www.federalregister.gov/documents/2019/11/05/2019-24124/endangered-and-
threatened-wildlife-and-plants-removing-oenothera-coloradensis-colorado-butterfly.
Water Quality Control Division (WQCD). 2002. Total Maximum Daily Load Assessment, Sediment,
North Fork Cache La Poudre River, Segment 7. Water Quality Control Division, Colorado
Department of Public Health and Environment. March 15.
EXHIBIT A TO RESOLUTION 2025-083
Western EcoSystems Technologies Inc. (WEST). 2016a. Wildlife Resources Technical Report for the
Halligan Water Supply Project Environmental Impact Statement. October.
Western EcoSystems Technologies Inc. (WEST). 2016b. Vegetation Resources Technical Report for the
Halligan Water Supply Project Environmental Impact Statement. October.
Western EcoSystems Technologies Inc. (WEST). 2017a. Species of Concern Technical Report for the
Halligan Water Supply Project Environmental Impact Statement. January.
Western EcoSystems Technologies Inc. (WEST). 2017b. Technical Report on the Effects of Altered Flows
on Wetland and Riparian Resources for the Halligan Water Supply Project Environmental Impact
Statement. February.
Woodling, John. 1985. Colorado’s Little Fish; A Guide to the Minnows and Other Lesser Known Fishes in
the State of Colorado. Published by the Colorado Department of Natural Resources, Division of
Wildlife.
Water Quality Control Commission (WQCC). 2020. Regulation 31: The Basic Standards and
Methodologies for Surface Water. 5 CCR 1002-31. Effective June 30, 2020.
Water Quality Control Commission (WQCC). 2021a. Regulation No. 38 – Classifications and Numeric
Standards for South Platte River Basin, Laramie River Basin, Republican River Basin, Smoky Hill
River Basin. 5 CCR 1002-38. Effective January 1, 2021.
Water Quality Control Commission (WQCC). 2021b. Regulation No. 93 – Colorado’s Section 303(D) List of
Impaired Waters and Monitoring and Evaluation List. 5 CCR 1002-93. Effective August 14, 2021.
EXHIBIT A TO RESOLUTION 2025-083
Appendix A
Mapbook
EXHIBIT A TO RESOLUTION 2025-083
LAS \\dc1vs01\gisproj\C\CityOfFortCollins\HalliganDam\MapFiles\Halligan_ProjectAreas_Mitigation_MBOverview.mxd 4/5/2023
VICINITY MAP
£¤287
Livermore
¬«14
North Poudre Can al Diversion Structure
Callow ay Diversion Structure
Halligan Dam
USGS Stream Gauge – NF Livermore
USGS Stream Gauge – NF Below Halligan Reservoir
Home PlaceParcel
North Poudre Can al (a.k.a. Livermore Can al)
Fort Collin s In take
Con fluen ce of th e North Fork an d th e Main stem of th e Poudre River
North Poudre Supply Can al (Mun roe Division )
USGS Stream Gauge – NF Above Halligan Reservoir
Bath Tub Sprin gs
Sprin g Gulch North
Sprin g Gulch South
Rufn er Camp
Cache la P
o
u
d
r
e
R
i
v
e
r
Sto
n
e
w
a
l
l
C
r
e
e
k
Meadow Cree
k
Six
m
i
l
e
C
r
e
e
k
Lone Pine Creek
Te
n
m
i
l
e
C
r
e
e
k
Da
l
e
C
r
e
e
k
Lo
n
e
t
r
e
e
C
r
e
e
k
Pa
r
k
C
r
e
e
k
Rabbit Creek
Krause Field
Home PlaceParcel
Ten mileParcel
Sprin g HillParcel
Boxelder
Bull PastureParcel
CherokeePark Rd
Map 1
Map 2
Map 3
Map 4
Map 5
Map 6
MiltonSeamanReservoir
HalliganReservoir
Joe W righ t Reservoir
Halligan Reservoir
Seaman Reservoir
Fort Collin s
Ch eyen n e
Lon gmon t
Greeley
Halligan W ater Supply ProjectVicin ity Map
LEGEND
Access Road
Project Area
Mitigation Area
Existing Ordinary High Water Mark
Proposed Ordinary High Water Mark
Roberts Ranch Conservation Easement
Stream
Canal
Roads
State Wildlife Area (SWA)
State Land Trust
US Forest Service
Eagle's Nest Open Space (Larimer County)
Phantom Canyon Preserve (TNC)
BLM
CSU
State Land Board $0 2.1
Miles
EXHIBIT A TO RESOLUTION 2025-083
LAS \\dc1vs01\gisproj\C\CityOfFortCollins\HalliganDam\MapFiles\Halligan_ProjectAreas_Mitigation_MB.mxd 4/5/2023
USGS Stream Gauge – NF Above Halligan Reservoir
Meadow Cree
k
Da
l
e
C
r
e
e
k
Krause Field
Cherokee Park
HalliganReservoir
Halligan Water Supply ProjectDetailed Map
LEGEND
Access Road
Project Area
Mitigation Area
Existing Ordinary High Water Mark
Proposed Ordinary High Water MarkNorth Fork Reaches
North Fork Above Halligan Reservoir
Current Halligan Reservoir
Roberts Ranch Conservation Easement
Stream
Roads
State Wildlife Area (SWA)
State Land Trust
US Forest Service
Phantom Canyon Preserve (TNC)
$0 3,000
Feet
EXHIBIT A TO RESOLUTION 2025-083
LAS \\dc1vs01\gisproj\C\CityOfFortCollins\HalliganDam\MapFiles\Halligan_ProjectAreas_Mitigation_MB.mxd 4/5/2023
North Poudre Canal Diversion Structure
Calloway Diversion Structure
Halligan Dam
USGS Stream Gauge – NF Below Halligan Reservoir
North Poudre Canal (a.k.a. Livermore Canal)
Lo
n
e
t
r
e
e
C
r
e
e
k
CherokeePark
HalliganReservoir
Halligan Water Sup p ly ProjectDetailed Map
LEGEND
Access Road
Project Area
Mitigation Area
Existing Ordinary High Water Mark
Proposed Ordinary High Water MarkNorth Fork Reaches
Current Halligan Reservoir
Upper Phantom Canyon
Lower Phantom Canyon
Livermore Valley above Rabbit Creek
Stream
Canal
Roads
State Wildlife Area (SWA)
State Land Trust
Phantom Canyon Preserve (TNC)
$0 3,000
Feet
EXHIBIT A TO RESOLUTION 2025-083
LAS \\dc1vs01\gisproj\C\CityOfFortCollins\HalliganDam\MapFiles\Halligan_ProjectAreas_Mitigation_MB.mxd 4/5/2023
North Poudre Canal Diversion Structure
Calloway Diversion Structure
Home PlaceParcel
North Poudre Canal (a.k.a. Livermore Canal)
Bath Tub Springs
Sto
n
e
w
a
l
l
C
r
e
e
k
Lone Pine Creek
Rabbit Creek
Home PlaceParcel
TenmileParcel
Spring HillParcel
Cherokee Park
Halligan Water Supply ProjectDetailed Map
LEGEND
Access Road
Project Area
Mitigation AreaNorth Fork Reaches
Upper Phantom Canyon
Lower Phantom Canyon
Livermore Valley above Rabbit Creek
Livermore Valley below Rabbit Creek
Roberts Ranch Conservation Easement
Stream
Canal
Roads
State Wildlife Area (SWA)
State Land Trust
Phantom Canyon Preserve (TNC)
$0 3,000
Feet
EXHIBIT A TO RESOLUTION 2025-083
LAS \\dc1vs01\gisproj\C\CityOfFortCollins\HalliganDam\MapFiles\Halligan_ProjectAreas_Mitigation_MB.mxd 4/5/2023
Spring Gulch North
Spring Gulch South
Rufner Camp
Pa
r
k
C
r
e
e
k
Boxelder
Halligan Water Supply ProjectDetailed Map
LEGEND
Mitigation Area
Roberts Ranch Conservation Easement
Stream
$0 3,000
Feet
EXHIBIT A TO RESOLUTION 2025-083
LAS \\dc1vs01\gisproj\C\CityOfFortCollins\HalliganDam\MapFiles\Halligan_ProjectAreas_Mitigation_MB.mxd 4/5/2023
£¤287
Livermore
USGS Stream Gauge – NF Livermore
Home PlaceParcel
Spring Gulch North
Spring Gulch South
Sto
n
e
w
a
l
l
C
r
e
e
k
Home PlaceParcel
Spring HillParcel
Bull PastureParcel
Halligan Water Supply ProjectDetailed Map
LEGEND
Mitigation AreaNorth Fork Reaches
Livermore Valley below Rabbit Creek
Eagles Nest
Roberts Ranch Conservation Easement
Stream
US Forest Service
Eagle's Nest Open Space (Larimer County)
$0 3,000
Feet
EXHIBIT A TO RESOLUTION 2025-083
LAS \\dc1vs01\gisproj\C\CityOfFortCollins\HalliganDam\MapFiles\Halligan_ProjectAreas_Mitigation_MB.mxd 4/5/2023
Fort Collins Intake
Confluence of the North Fork and the Mainstem of the Poudre River
North Poudre Supply Canal (Munroe)Cache la P
o
u
d
r
e
R
i
v
e
r
MiltonSeamanReservoir
Halligan Water Supply ProjectDetailed Map
LEGEND
Mitigation AreaNorth Fork Reaches
Eagles Nest
Seaman Reservoir
Below Seaman Reservoir Reach
Stream
Canal
State Wildlife Area (SWA)
State Land Trust
US Forest Service
$0 3,000
Feet
EXHIBIT A TO RESOLUTION 2025-083
Appendix B
Summary of Mitigation Measures
EXHIBIT A TO RESOLUTION 2025-083
Appendix B. Summary of Mitigation Measures
Table B-1. FWMEP Measures and Costs
Measurement
Type
Mitigation, Monitoring,
and Enhancement
Measure
FWMEP Section Purpose for Measure Description of the Commitment[a] Fort Collins
Total
Capitalized
Cost[b]
FWMEP
Capitalized
Cost[b]
Avoidance
and
Minimization
Mitigation
Measures
Winter Release Plan 4.2.1.1 As part of Halligan Project operations, Fort Collins will provide
continuous releases of 3 cfs from its water stored in the enlarged
Halligan Reservoir to the North Fork from October 1 through April 30
each year.
NPIC cannot divert the winter releases into the North Poudre Canal
pursuant to an existing agreement with Fort Collins. The Halligan
Project involves reconstructing the North Poudre Canal Diversion
similar to its current configuration but to allow the bypass of Fort
Collins’ releases from the enlarged Halligan Reservoir so that the water
remains in the North Fork.
The Winter Release Plan will result in benefits to the North Fork by
eliminating almost all zero-flow days on the North Fork (in
combination with the Summer Low-flow Plan [Section 4.2.1.2]).
Provide a continuous, more longitudinally connected aquatic corridor
compared to the existing zero-flow conditions, create additional
wetted channel area that will benefit small-bodied native fish, trout,
and macroinvertebrates, and re-establish basic habitat requirements
for aquatic species through the reintroduction of perennial flow.
The Winter Release Plan will also result in benefits that will offset the
impact resulting from the inundation of approximately 0.75 mile of
the CWCB’s instream flow water right (Water Court Case
1985CW430) on the North Fork above Halligan Reservoir.
Fort Collins will implement the Winter Release Plan the first winter
after the new Halligan Dam has been approved to store water by the
DWR and Fort Collins’ portion of the enlarged reservoir has at least
3,000 acre-feet of water.
$1,654,375 $0
EXHIBIT A TO RESOLUTION 2025-083
Measurement
Type
Mitigation, Monitoring,
and Enhancement
Measure
FWMEP Section Purpose for Measure Description of the Commitment[a] Fort Collins
Total
Capitalized
Cost[b]
FWMEP
Capitalized
Cost[b]
Avoidance
and
Minimization
Mitigation
Measures
Summer Low-Flow Plan 4.2.1.2 Fort Collins will implement the Summer Low-Flow Plan, which adjusts
reservoir operations by forgoing diversions and/or releasing its water
stored in the enlarged Halligan Reservoir to maintain a minimum
continuous 5 cfs flow in the approximately 22 miles of the North Fork
between the replacement Halligan Dam and Seaman Reservoir (as
measured at three gaging stations along the North Fork) from May 1 to
September 30 each year (summer releases).
NPIC cannot divert the winter releases into the North Poudre Canal
pursuant to an existing agreement with Fort Collins. The Halligan
Project involves reconstructing the North Poudre Canal Diversion
similar to its current configuration but to allow the bypass of Fort
Collins’ releases from the enlarged Halligan Reservoir so that the water
remains in the North Fork.
The Summer Low-Flow Plan will result in benefits to the North Fork
by eliminating almost all zero-flow days on the North Fork (in
combination with the Winter Release Plan, Section 4.2.1.1), which
avoids and minimizes potential impacts on the aquatic ecosystem,
including stream temperature from the Halligan Project.
The Summer Low-flow Plan would increase flow rates on the North
Fork in summer months at the times of the lowest current flow rates
with anticipation of stream temperature benefits for the North Fork.
Provide a continuous, more longitudinally connected aquatic corridor
compared to the existing zero-flow conditions, create additional
wetted channel area that will benefit small-bodied native fish, trout,
and macroinvertebrates, and re-establish basic habitat requirements
for aquatic species through the reintroduction of perennial flow.
The Summer Low-Flow Plan will also result in benefits that will offset
the impact resulting from the inundation of approximately 0.75 mile
of the CWCB’s instream flow water right (Water Court Case
1985CW430) on the North Fork above Halligan Reservoir.
Based on Commission and public feedback, Fort Collins will also
perform preconstruction surveys of the pre-Halligan Reservoir
enlargement flows on the reach of the North Fork between the
existing Livermore gage and the upstream end of Seaman Reservoir
(that is, the Livermore-to-Seaman Reach) in different seasons and
hydrologic regimes (particularly dry conditions) to determine if there
are flow losses in this stretch. Details of the preconstruction surveys,
including an agreement on methods and standards to be used to
define whether there are flow losses will be included in an
intergovernmental agreement between Fort Collins and CPW. If the
preconstruction survey demonstrates that the Livermore-to-Seaman
Reach is a neutral or gaining reach, then another gage below the
existing Livermore gage will not be needed. If the preconstruction
survey demonstrates that the Livermore-to-Seaman Reach is a losing
reach, Fort Collins will coordinate with CPW on next steps which
could include the installation of a fourth gage or increased Halligan
Project flows to the Livermore gage to offset such losses toward
ensuring that the Summer Low-flow Plan benefits all 22 miles of
river.
If, in the future, another diversion structure is constructed in the
Livermore-to-Seaman Reach, Fort Collins will commit to work with
the owner of this diversion structure toward assuring passage of Fort
Collins' flows. The commitment with the future diversion structure
owner could include a written agreement, installation of other gages,
and/or other means of assuring that Fort Collins can meet its
Summer Low-flow Plan measure.
$830,875 $0
EXHIBIT A TO RESOLUTION 2025-083
Measurement
Type
Mitigation, Monitoring,
and Enhancement
Measure
FWMEP Section Purpose for Measure Description of the Commitment[a] Fort Collins
Total
Capitalized
Cost[b]
FWMEP
Capitalized
Cost[b]
Avoidance
and
Minimization
Mitigation
Measures
Modified Summer Release
Exchange Program
4.2.1.2 Fort Collins will not exchange Summer Low-flow Plan releases (up to 5
cfs) from Halligan Reservoir up to either of the Fort Collins Intakes. This
hiatus on exchanges will occur each year from July 1 to September 30.
This action will leave more water in the Main Stem upstream of the
North Fork confluence and downstream to below the Hansen Supply
Canal during times of the most critical temperature concern (July to
September), minimizing Halligan Project temperature impacts in this
critical season.
$645,000 $0
Avoidance
and
Minimization
Mitigation
Measures
Operational Agreement
with Greeley
4.2.1.3 Fort Collins is pursuing an operational agreement with Greeley. The
agreement would specify the need for Greeley to pass Halligan
Releases, including the Winter Release and Summer Low-flow Plan of 3
cfs and up to 5 cfs directly through Seaman Reservoir. For this to be
possible, upgraded outlet works may be needed in Seaman Reservoir.
Greeley is currently in the process of upgrading their outlet works with
support from federal funding. As part of the potential agreement, Fort
Collins may provide additional funding support for further refinement
of the new outlet works design for Seaman Reservoir. The goal of this
additional funding would be to give the new outlet works the
functionality and operational control to pass even the small Summer
Low-flow Plan releases through Seaman Reservoir (that is, the refined
new outlet works should allow for fine-scale management of releases
on the order of 1 to 5 cfs).
Fort Collins is pursuing the Greeley Agreement because, if the
diversion and storage of Halligan Project summer releases by Greeley
in Seaman Reservoir could be avoided, the river temperature
benefits of the Summer Low-flow Plan could be extended to the
approximately 1 river mile reach of the North Fork below Seaman
Reservoir.
In the event that Fort Collins cannot reach an agreement with
Greeley to pass Fort Collins’ Halligan Winter and Summer Low-flow
Plan releases of 3 cfs and up to 5 cfs below Seaman Reservoir, and
the CWA Section 401 water quality certification process determines
that the Halligan Project has potential for occasional adverse
temperature impacts on the North Fork below Seaman Reservoir
that requires mitigation, Fort Collins commits to mitigating the
identified temperature impacts attributable to the Halligan Project
through stream restoration or other measures in a manner agreed to
by Fort Collins, CDPHE, and CPW. If reasonably practicable,
Fort Collins will mitigate the identified impacts along the river reach
from Seaman Reservoir to the confluence with the Main Stem
commensurate with Fort Collins identified impacts. If not reasonably
practicable in the reach below Seaman Reservoir, Fort Collins will
work with CDPHE and CPW to find other mitigation commensurate
with the Halligan Projects identified impacts.
$1,150,000 $0
Avoidance
and
Minimization
Mitigation
Measures
Ramping Rates Limitations 4.2.1.4 By applying ramping rate limitations, Fort Collins will seek to constrain
existing and potential dramatic decreases and increases in the rate of
discharge from Fort Collins’ portion of the enlarged Halligan Reservoir
to avoid and minimize impacts on aquatic species, particularly small-
bodied native fish and rainbow trout. The ramping rate limitations will
also help maintain a more natural descending limb of the North Fork
hydrograph following peak flows by incorporating a more gradual
decrease in outflow and establishing a lag time before returning the
stream to a base flow level.
Ramping Rate limitations would take effect as soon as the new
Halligan Dam has been approved to store water by DWR.
The ramping rate limitations are intended to protect aquatic life, as
well as people recreating (for example, fishing) downstream,
minimizing Fort Collins' impacts to aquatic ecosystems. Fort Collins
will limit dramatic decreases and increases in the discharge rate
resulting from Fort Collins’ operation of its portion of the enlarged
Halligan Reservoir. The details of ramping rate limitations to
decreasing discharge rates and increasing discharge rates are
described in Section 4.2.1.4 of the FWMEP.
$625,000 $625,000
EXHIBIT A TO RESOLUTION 2025-083
Measurement
Type
Mitigation, Monitoring,
and Enhancement
Measure
FWMEP Section Purpose for Measure Description of the Commitment[a] Fort Collins
Total
Capitalized
Cost[b]
FWMEP
Capitalized
Cost[b]
Avoidance
and
Minimization
Mitigation
Measures
Peak-Flow Bypass
Program
4.2.1.5 When the forecast peak flow has been estimated to within a few days,
Fort Collins will forgo all diversions into its portion of the enlarged
Halligan Reservoir for three days coinciding as closely as practicable, as
detailed below, with the annual forecasted peak (runoff) flow event for
the North Fork. The Peak Flow Bypass Program will allow 3 days (in
addition to ramping rate limits Section 4.2.14) of peak flows during
times when Fort Collins could be diverting water into storage in the
enlarged Halligan Reservoir.
The Peak flow bypass program would take effect as soon as the new
Halligan Dam has been approved store water by DWR.
The Peak Flow Bypass Program will avoid and minimize impacts on
the aquatic ecosystem from the Halligan Project by maintaining
some of the historical, pre-enlargement peak flows past the enlarged
Halligan Reservoir. This Peak Flow Bypass Program is intended to
mimic a natural, pre-enlargement stream flow for this 3-day period
(in addition to ramping) to support riverine and ecological processes
in the North Fork, such as the following:
Providing phenological cues to aquatic and riparian organisms for
emergence of aquatic insects, spawning, the timing of flowering,
and seed dispersal
Facilitating natural seasonal sediment transport, channel shaping,
and channel scour
Recruiting and transporting woody debris and other organic
materials
Providing overbank flooding to maintain wetland and riparian
habitat function, including seed transport and propagation of
native cottonwood and willow species, sediment transport,
formation and maintenance of aquatic habitat, and riparian area
diversity and structure
$765,000 $0
Avoidance
and
Minimization
Mitigation
Measures
End of Summer Flushing
Event
4.2.1.6 An end of summer flushing event (flushing event) will be conducted
following fall turnover of Halligan Reservoir each year that a turnover
event occurs (turnover is anticipated to occur in all years of normal
Halligan Project operations) to address potential iron coatings on river
materials. The intention of the flushing event would be to flush
seasonal iron deposition (if it occurs) from sediment surfaces below the
dam to minimize the potential adverse effects of such deposition,
which is most likely to occur in late summer, if it were to occur.
The goal of the end of summer flushing event is to release a
maximum of 30 acre-feet of water at the lowest discharge rate from
the outlet of the enlarged Halligan Reservoir that is practicable to
successfully mobilize the iron deposits. Targeting lower effective flow
rates is desirable to avoid unintended adverse consequences on
small-bodied fish and inadvertent sediment release.
The first flushing event would occur after the new Halligan Dam has
been approved to store water by DWR and Fort Collins’ portion of
the reservoir has filled and there has been a reservoir turnover, as
described in Section 4.2.1.6.
To avoid unintended adverse effects on small-bodied native fish and
sediment, Fort Collins will seek CPW input regarding the planned
rate, ramping, and timing of the release each year. Fort Collins would
also monitor iron and habitat conditions immediately below the
enlarged reservoir for 5 years to determine if this flushing event is
effective and/or necessary. This monitoring will consist of visual
checks for iron deposition on sediment in the vicinity of the NBH
sampling station (and photographic records of any observed
deposition) as well as continued sampling at NBH for dissolved and
total iron. However, if it is determined at the end of the first five
flushing events following construction (in consultation with CPW)
that this operation is no longer needed, then the releases and special
monitoring (observations of iron deposition) will end.
$7,650 $0
EXHIBIT A TO RESOLUTION 2025-083
Measurement
Type
Mitigation, Monitoring,
and Enhancement
Measure
FWMEP Section Purpose for Measure Description of the Commitment[a] Fort Collins
Total
Capitalized
Cost[b]
FWMEP
Capitalized
Cost[b]
Avoidance
and
Minimization
Mitigation
Measures
Legal Protection of Flows 4.2.1.1., 4.2.1.2, and 4.3.8 Through the Flow-related operational measures (Winter Release Plan,
Summer Low-Flow Plan, Peak Flow Bypass) and Temporary
Environmental Pool enhancement, Fort Collins will provide additional
stream flow. NPIC cannot divert these flows into the North Poudre
Canal pursuant to an existing agreement with Fort Collins. Additionally,
Fort Collins will undertake a good faith effort to protect the Summer
Releases from Halligan Reservoir to Seaman Reservoir using the
“Protected Mitigation Release” statute (CRS 37-92-102[8]) in the same
manner and subject to the same limitations as described for the Winter
Release Plan.
Avoid/minimize impacts to aquatic species by protecting Halligan
release from being removed between Halligan and the Mainstem of
the Poudre.
If Fort Collins fails to acquire a Water Court decree to protect
Halligan Releases under the Protected Mitigation Release statute, or
its agreement with NPIC changes such that Halligan Releases can be
diverted into the North Poudre Canal, Fort Collins will consult with
CPW in good faith to evaluate how Halligan Releases can be
protected.
$250,000 $250,000
Avoidance
and
Minimization
Mitigation
Measures
Multi-Level Outlet
Structure
4.2.2.1 A multilevel outlet works (MLOW) for Halligan Reservoir that would
allow water to be released from one or more elevation higher than the
bottom has been discussed since the CMP was put forth in the DEIS. An
MLOW is a tool that can, in some cases, allow for beneficial additional
management controls on the quality of water released from a reservoir,
particularly at times of stratification. At this time, however, an MLOW is
not expected to be necessary from the perspective of aquatic life
mitigation efforts. Therefore, based on CPW comment, the MLOW is
not a commitment in the FWMEP, but the need for an MLOW may be
revisited through the 401 certification process.
During the 401 Certification process modeling and analysis findings
will be reviewed to assess whether such a structure would provide
effective and practical water-quality management options for
mitigating anticipated project water-quality impacts. CWA Section
401 water quality certification model findings will be shared, and
CPW and CDPHE will be consulted on this decision, as part of the
CWA Section 401 water quality certification process.
$0 $0
Avoidance
and
Minimization
Mitigation
Measures
Outlet Conduit Sizing 4.2.2.2 To allow for the peak flow bypass mitigation measure (Section 4.2.1.5),
Fort Collins incorporated an enlarged outlet conduit, which is larger
than necessary to meet demand-based releases. The enlarged outlet
will be constructed to release up to 800 cfs.
Minimize impacts to aquatic ecosystems by upsizing outlet size to
allow peak flow bypass.
$0 $0
Avoidance
and
Minimization
Mitigation
Measures
Big Game Interference
Minimization
4.2.3.1 Fort Collins aims to avoid and minimize the Halligan Project’s potential
impacts on wildlife within the Halligan Project Area when feasible. The
Halligan Project includes many construction-related measures designed
to avoid and minimize impacts on big game.
Information specific to bighorn sheep is discussed in sections 4.2.3.17,
4.2.3.18, and 4.2.3.19.
Construction-related measures to avoid and minimize impacts on big
game, including the following measures. Because these measures
also benefit other resources, they are described elsewhere in the
FWMEP:
Construction scheduling to ensure efficient project delivery, to
limit temporal impacts and number of seasons during which
habitat is disturbed (4.2.3.13)
Construction carpooling (Section 4.2.3.11)
Management of fugitive dust during construction (Section 4.2.3.7)
Minimizing construction disturbance areas Minimization of and
the number and footprint of construction access roads and
construction areas (Sections 4.2.3.9, 4.2.3.10, and 4.2.3.14)
Reclamation and revegetation of temporarily disturbed areas
(Section 4.2.3.9)
Implementation of a noxious and invasive weed management plan
for construction and reclamation activities (Section 4.2.3.15).
Compensatory mitigation and enhancement measures specific to
bighorn sheep are described in Sections 4.3.3 and 5.2.3.
$0 $0
EXHIBIT A TO RESOLUTION 2025-083
Measurement
Type
Mitigation, Monitoring,
and Enhancement
Measure
FWMEP Section Purpose for Measure Description of the Commitment[a] Fort Collins
Total
Capitalized
Cost[b]
FWMEP
Capitalized
Cost[b]
Avoidance
and
Minimization
Mitigation
Measures
Preconstruction Botanical
Surveys
4.2.3.2 Previous botanical surveys have not located Ute ladies’-tresses orchid
in the area of Halligan Reservoir.
To further minimize the possibility of Project impacts on this
federally threatened plant, botanical surveys will be conducted at a
minimum of a year before construction. Surveys will focus on areas
that will likely be disturbed by the Halligan Project and that could
support the orchid, and be performed during the growing season
(July and August). Results of preconstruction surveys will be
submitted to USFWS as required by the ESA; CPW will be provided a
courtesy copy of results.
$10,200 $0
Avoidance
and
Minimization
Mitigation
Measures
Preconstruction Bat
Surveys
4.2.3.3 Visual and auditory detection surveys for bats were conducted in the
area of Halligan Dam and up to 0.5 mile downstream of Halligan Dam in
2021. Several lone bats were detected during the surveys, but no large
concentrations of bats were identified. The scattered occurrence of
lone bat detections suggests that the area below Halligan Dam is used
for foraging, but evidence of a bat colony or identification of roosting
locations was not observed during this brief presence/absence survey.
To minimize the possibility of Project impacts on bats, additional
surveys are warranted, including a survey for roosting sites near the
dam. This additional bat survey work will be conducted in the year
before construction commences for the Halligan Project. Surveys will
focus on areas that will likely be disturbed by Halligan Project
construction activities. If surveys indicate the presence of an active
bat roost near the Halligan Dam, Fort Collins will consult with CPW
on appropriate mitigation measures.
$10,200 $10,200
Avoidance
and
Minimization
Mitigation
Measures
Migrating Bird and
Raptors Survey
4.2.3.4 Nest surveys were conducted in the area of Halligan Dam and along
access roads in 2021.
Additional monitoring for migratory birds and raptors will be
performed every other year before construction, the year before the
start of construction, and annually during construction with a focus
on areas of suitable habitat within planned or proposed disturbance
areas in the immediate Halligan Project Area. Before and during
construction activities, Fort Collins may use bird nesting deterrents
during nesting season to reduce the risk of nesting activities during
construction. Deterrent measures may include modifying or
removing attractive nesting habitat (for example, trees, shrubs, tall
grass) within potential disturbance areas during inactive periods to
reduce the potential for construction-related impacts during active
nesting periods. Before Project implementation, Fort Collins will
provide CPW an opportunity to review and comment on Project
specifications related to migratory bird and raptor nesting avoidance
and minimization.
$70,800 $0
Avoidance
and
Minimization
Mitigation
Measures
Raptor Nesting or
Roosting Platforms
4.2.3.5 Fort Collins will include nesting or roosting platforms near Halligan
Reservoir to encourage eagles and other raptors, such as osprey, to use
the reservoir.
The platforms will also minimize any temporary loss of perching
locations from the inundation of shoreline trees while new shoreline
habitat becomes established. The final design and location of nesting
or roosting platforms will be developed in coordination with CPW.
The nesting or roosting platforms will be installed as part of the
project construction. At this time the exacting timing is not known.
However, the nesting or roosting platforms will be installed before
inundation of the enlarged Halligan Reservoir begins.
$12,400 $0
EXHIBIT A TO RESOLUTION 2025-083
Measurement
Type
Mitigation, Monitoring,
and Enhancement
Measure
FWMEP Section Purpose for Measure Description of the Commitment[a] Fort Collins
Total
Capitalized
Cost[b]
FWMEP
Capitalized
Cost[b]
Avoidance
and
Minimization
Mitigation
Measures
Stormwater Management
Plan
4.2.3.6 Targeted planning and successful execution of the stormwater
management plan will reduce the potential for water quality
degradation of the North Fork and its associated aquatic ecosystem.
Fort Collins will develop a stormwater management plan in
compliance with local and state requirements and as required by the
National Pollutant Discharge Elimination System (NPDES),
Construction General Permit, COR400000 prior to construction,
which will include all necessary stormwater management controls
and best practices, temporary sediment and erosion control during
construction, and medium-term sediment and erosion control during
vegetation reestablishment. Additionally, a non-stormwater
discharge permit and monitoring plan will be prepared, if required,
before the start of construction.
$14,800 $0
Avoidance
and
Minimization
Mitigation
Measures
Best Management
Practices
4.2.3.7 Fort Collins will employ standard construction best management
practices (BMPs; also called control measures) typically included in
federal, state, and local permit requirements to reduce potential
construction-related impacts on upland and aquatic habitats, fish, and
water quality. BMPs will be implemented at Project construction areas
including dam construction and staging/stockpile areas, along access
roads, the North Poudre Canal Diversion structure, and mitigation or
enhancement sites that involve City-led construction. At a minimum,
BMPs will include:
Erosion control measures
Sediment control measures
Dust suppression measures
Non-stormwater controls and waste and materials management
Material management and waste management
Avoid and minimize impacts to aquatic and terrestrial ecosystems.
Refer to the FWMEP text for the complete list of best management
practices. Additional measures may be incorporated if those
described differ from permit conditions defined in the CWA Section
401 water quality certification and CWA Section 404 permit, or if site
conditions warrant them.
$1,171,250 $48,750
Avoidance
and
Minimization
Mitigation
Measures
Existing Dam for
Construction Sediment
Control
4.2.3.8 Leaving the original dam in place during construction to act as a coffer
dam provides strong control of sediment to allow for avoidance of an
inadvertent major release of sediment during construction. The existing
dam will continue to function normally during the entire time the
replacement dam is being constructed; therefore, drawdown of the
reservoir will not be necessary during construction. Once the
replacement dam is complete, Fort Collins anticipates that a coffer dam
will be put in place around the existing dam during the brief (a few
months or less) demolition period.
Avoid and minimize impacts to aquatics by controlling existing
reservoir sediments during construction.
$0 $0
Avoidance
and
Minimization
Mitigation
Measures
Construction Disturbance
Minimization and
Reclamation
4.2.3.9 Fort Collins will reclaim temporarily disturbed areas following
construction completion. Materials stockpile and borrow areas created
on Fort Collins’ property may be left in place for long-term operations
and maintenance of the enlarged Halligan Reservoir.
Reclaiming disturbed areas to their current condition will reduce the
permanent footprint of the Halligan Project and reduce the potential
for long-term ecological degradation. Revegetation and monitoring is
described in Sections 4.2.3.7 and 4.2.3.15.
$533,170 $0
EXHIBIT A TO RESOLUTION 2025-083
Measurement
Type
Mitigation, Monitoring,
and Enhancement
Measure
FWMEP Section Purpose for Measure Description of the Commitment[a] Fort Collins
Total
Capitalized
Cost[b]
FWMEP
Capitalized
Cost[b]
Avoidance
and
Minimization
Mitigation
Measures
Access Road Minimization
and Reclamation
4.2.3.10 To accommodate larger vehicles and equipment necessary to construct
the Halligan Project and to implement some of the mitigation measures
described herein existing roads will require some or all of the following:
temporary widening to accommodate two-way truck traffic in some
locations, placement of new culverts at drainage crossings, grade
modifications, and road stabilization. In addition, use of the western
access road will be limited as discussed in section 4.2.3.14
Fort Collins proposes using existing roads whenever possible and to
reclaim access roads to their current condition following
construction completion to reduce the permanent footprint of the
Halligan Project and reduce the potential for long-term ecological
degradation.Widened roads and turnouts created on Fort Collins
property may be left in place for long-term operations and
maintenance of the enlarged Halligan Reservoir; widened roads may
be left in place on private property if requested by the landowner.
$533,170 $0
Avoidance
and
Minimization
Mitigation
Measures
Traffic Impact
Minimization
4.2.3.11 Traffic impacts on residents will be limited to predominant ingress and
egress from Highway 287, with less ingress and egress from Larimer
County Road 80C (Cherokee Park Road). Given the complexity of
construction activities associated with the Halligan Project, large
amounts of staffing will be required to access the construction zone
throughout Project construction.
To minimize impacts on traffic on Highway 287, Fort Collins will
construct a temporary or permanent turn lane and/or an
acceleration lane. This minimization measure will be designed and
implemented in coordination with the Colorado Department of
Transportation and Larimer County.
Fort Collins will incorporate carpooling of staff to and from
construction areas. Carpooling of staff will reduce traffic on access
roads and minimize air quality impacts, greenhouse gas emissions,
potential wildlife and vehicle collisions, and fugitive dust during
construction.
To minimize traffic impacts on wildlife as noted here, as well as
Sections 4.2.3.1, 4.2.3.7, and 4.2.3.9, will minimize impacts on
wildlife by using existing roads, reducing traffic-related equipment
emissions and noise, reducing fugitive dust, reducing the potential
for wildlife vehicle collisions, and reducing displacement and
disturbance of habitats adjacent to construction activities and access
roads. Construction of a temporary river crossing on the North Fork
below the replacement dam will minimize traffic along County Road
80C by allowing direct access to the west side of Halligan Dam during
construction (Section 4.2.3.14).
$296,749 $0
Avoidance
and
Minimization
Mitigation
Measures
Construction Impact
Minimization that will
Benefit Wildlife
4.2.3.12 Construction of certain elements of the Halligan Project are anticipated
to occur throughout all hours of the day or night during certain
construction milestones. Fort Collins proposes to minimize nighttime
construction activities that have the potential to generate increased
noise levels, such as blasting, and will proactively respond to noise
complaints. Lighting impacts associated with Halligan Project nighttime
construction activities will be minimized in consideration of both local
residents and wildlife.
Lighting during construction will be limited to what is necessary for
safety and security on the Project site during construction. Lighting
will be angled and shielded to avoid light pollution and impacts on
neighbors and wildlife.
Noise will be minimized to the extent practicable during
construction; Fort Collins plans to fit equipment with mufflers and
apply construction standard practices for noise construction (the
specific practices will depend on equipment used).
Fort Collins’ contractors will comply with Larimer County ordinances
or approved variance requests through the county that may include
noise shielding and reduction of after-hours activities.
$0 $0
EXHIBIT A TO RESOLUTION 2025-083
Measurement
Type
Mitigation, Monitoring,
and Enhancement
Measure
FWMEP Section Purpose for Measure Description of the Commitment[a] Fort Collins
Total
Capitalized
Cost[b]
FWMEP
Capitalized
Cost[b]
Avoidance
and
Minimization
Mitigation
Measures
Construction Timing
Restrictions at the North
Poudre Canal and
Calloway Diversions
4.2.3.13 To minimize potential construction-related disturbance to bighorn
sheep spring and fall movements, Fort Collins and CPW have agreed to
implement a 1-year construction window for both the North Poudre
Canal and Calloway Diversions. To the extent reasonably possible, all
work will be completed within one construction season beginning in
November and ending the following end of March.
During the 1-year construction window, Fort Collins will perform
work in two phases. During the first phase, work on the access road
construction, and staging equipment and materials at the North
Poudre Canal and Calloway Diversions will occur in July and August.
Then during the second phase, both the North Poudre Canal and
Calloway Diversions construction work will commence in November
and conclude in March before spring movements by bighorn sheep
through the mapped linkage area between the two diversion
structures. To the extent reasonably possible, all work will be
completed within one construction season beginning in November
and ending the following end of March. In the unlikely event of an
unforeseen occurrence such as extreme snow, Fort Collins will
coordinate with CPW to develop a revised schedule. In addition, Fort
Collins has not yet come to an agreement with landowners to
complete channel improvements and modifications of the Calloway
Diversion. Should a delay occur that affects the proposed timing
restriction schedule, Fort Collins will coordinate with CPW and
landowners to discuss an alternative timeline to avoid or minimize
impacts to bighorn sheep as discussed in Sections 4.2.3.17, 4.2.3.19,
and 5.1.1.4
$109,500 $109,500
Avoidance
and
Minimization
Mitigation
Measures
Limited Use of Western
Access Road
4.2.3.14 Following completion of the temporary construction access crossing of
the North Fork below the Halligan Dam, which is planned in the first
year of construction, use of the western access road intersecting
Larimer County Road 80C (Cherokee Park Road) will be reduced to only
occasional or as-needed access from April to July in the second and
subsequent years of construction to reduce construction vehicle
disturbance to wildlife in the area.
Minimization of potential animal and vehicular interference along
Cherokee Park Road.
$0 $0
Avoidance
and
Minimization
Mitigation
Measures
Noxious and Invasive
Weed Control and
Revegetation
4.2.3.15 Restoration and revegetation will be completed for all temporarily
disturbed areas using native plants. These disturbance areas will be
monitored after construction to ensure successful re-establishment of
vegetation in accordance with Construction General Permit
requirement to stabilize all disturbed soil areas (Section 4.2.3.94.2.3.15)
before completion of the Halligan Project. Specific
revegetation/restoration details will be identified following final design.
Fort Collins will develop a noxious and invasive weed management
plan for construction activities, in coordination with the Larimer
County Weed District. No domestic sheep or goats will be used for
weed control on City-owned property or easements Fort Collins
grants to others in the vicinity of Halligan Reservoir. Noxious weed
BMPs, including chemical, cultural, and mechanical measures, will be
implemented during all construction phases for all Halligan Project
disturbance areas, including access roads and buffers. Equipment will
be cleaned so that it is free of accumulated soils that may carry
noxious and invasive weed seeds to the Halligan Project Area
$96,264 $0
EXHIBIT A TO RESOLUTION 2025-083
Measurement
Type
Mitigation, Monitoring,
and Enhancement
Measure
FWMEP Section Purpose for Measure Description of the Commitment[a] Fort Collins
Total
Capitalized
Cost[b]
FWMEP
Capitalized
Cost[b]
Avoidance
and
Minimization
Mitigation
Measures
Aquatic Nuisance Species 4.2.3.16 Fort Collins will take a proactive approach to preventing the
introduction of aquatic nuisance species into Halligan Reservoir, the
North Fork, and the Main Stem. Non-native species and invasive species
pose a threat to ecosystems, and Fort Collins will minimize the risk of
spreading aquatic nuisance species through implementation of BMPs to
prevent the potential spread of these species in Halligan Reservoir and
in the rivers.
Fort Collins will implement specific procedures to ensure that all
equipment is cleaned of mud and debris (for example, tracks, turrets,
buckets, drags, teeth), and inspected to confirm they are free of
aquatic nuisance species. Specific decontamination measures for
equipment or materials that were used in any stream, river, lake,
pond, or wetland within 14 days of the start of the project to prevent
the spread of New Zealand mudsnails, zebra and quagga mussels,
invasive plant species, and other aquatic nuisance species will follow
the most current guidance from CPW and are expected to include
one or more of the following methods:
1. Remove all mud and debris from equipment (tracks, turrets,
buckets, drags, and teeth) and spray/soak in a 1:15 solution of
Quat 4 or Super HDQ Neutral institutional cleaners and water.
Keep equipment moist with the solution for at least 10 minutes.
2. Remove all mud and debris from equipment (tracks, turrets,
buckets, drags, and teeth) and continuously spray/soak
equipment with water that is hotter than 140 degrees Fahrenheit
for at least 10 minutes. Hand tools, boots, and any other
equipment that will be used in the water will be cleaned, as well.
$30,000 $0
Avoidance
and
Minimization
Mitigation
Measures
Bighorn Sheep Habitat
Improvements
4.2.3.18 Fort Collins in consultation with CPW, has identified several areas
within the Cherokee SWA that would provide the largest benefit to
bighorn sheep habitat and foraging through cheatgrass mitigation. The
habitat treatment targets cheatgrass seed germination, allowing for
higher quality native forage to grow, which, in turn, may keep the Lone
Pine herd within the boundaries of Cherokee SWA longer and away
from domestic sheep during the April to July grazing period. The
treatment should not alter normal migration routes, habitat range use,
or lambing areas.
Funding will be provided to CPW will install either two water guzzlers
for precipitation capture or one water guzzler and one stock-tank type
structure that uses water from a spring that CPW holds rights to
develop. These features will passively (that is, external power source
not needed) provide water sources away from Halligan Project
disturbances and are expected to provide benefit before, during, and
after construction. The water features will be used to enhance bighorn
sheep habitat in areas that may be underused due to lack of water
resources and within a reasonable distance of the priority habitat
restoration area noted previously.
To improve bighorn sheep habitat opportunities and water access on
the Cherokee SWA, Fort Collins will provide to CPW $250,000 for
chemical treatment to abate invasive cheatgrass over at least 500
acres, along with other habitat improvements. Funding is to
complete a minimum of one round of cheatgrass treatment over 500
acres and other habitat improvements that may include the
installation of up to two remote passive water sources at least 2
years before the start of project construction in an effort to entice
bighorn sheep away from construction areas and areas at times used
for the grazing of domestic sheep. Any remaining monies up to the
$250,000 earmarked for vegetation and habitat restoration could be
used by CPW for habitat treatment on additional acreages within the
Cherokee SWA.
If additional water features are appropriate for the area, CPW will
also consider location and design elements that would exclude
domestic ruminants from using the water sources, such as wildlife
friendly fencing, to minimize the potential for pathogen
transmission. The water features will be used to enhance bighorn
sheep habitat in areas that may be underused due to lack of water
resources and within a reasonable distance of the priority habitat
restoration area noted previously.
$250,000 $250,000
EXHIBIT A TO RESOLUTION 2025-083
Measurement
Type
Mitigation, Monitoring,
and Enhancement
Measure
FWMEP Section Purpose for Measure Description of the Commitment[a] Fort Collins
Total
Capitalized
Cost[b]
FWMEP
Capitalized
Cost[b]
Avoidance
and
Minimization
Mitigation
Measures
Bighorn Sheep Collaring
Study
4.2.3.19 Support CPW in collaring and disease testing of bighorn sheep from the
Lone Pine her to track their movements before, during, and
immediately after Halligan Project construction. Collaring study results
will support evaluation of whether construction may influence herd
habits, in particular with respect to interactions with domestic sheep
and/or other bighorn herds. CPW will implement the collaring study.
GPS collar monitoring studies are needed to assess disease risk and
habitat restoration needs for the Lone Pine Herd by gathering data on
herd landscape use (habitat, spatial and temporal), recruitment, and
overall health. Depending upon the Lone Pine Herd size, up to a
maximum of 15 collars may be deployed.
Fort Collins will provide CPW additional funding of up to $120,000 to
support global positioning system (GPS) collaring and disease testing
of up to a maximum of 15 bighorn sheep from the Lone Pine herd.
The preconstruction portion of the GPS collaring study including, and
disease testing will begin no less than 2 years before the anticipated
start of the Halligan Project construction. GPS collars are expected to
have a 2-year life and collect data approximately every 4 hours.
Preconstruction collaring data will be considered viable for 5 years.
Should construction be pushed beyond that initial 5-year window, a
second GPS collar study would start 1 year from the start of
construction. The intent of the second preconstruction GPS collar
study including, and disease testing is to have accurate and recent
data on the Lone Pine herd’s movements before construction. The
Lone Pine herd will be fitted with GPS collars and undergo disease
testing during all of the construction with collars having an
anticipated 2-year battery life. The final phase will be a 2-year
postconstruction GPS collaring and disease testing event to evaluate
postconstruction movement and habitat use. CPW may euthanize
bighorn sheep to prevent disease spread in the Lone Pine herd
and/or adjacent herds. As discussed in Section 4.3.3 Fort Collins will
provide monetary compensation for any bighorn sheep culls from
the Lone Pine herd.
$120,000 $120,000
Avoidance
and
Minimization
Mitigation
Measures
Overhead Power Line and
Pole Relocation
4.2.3.20 The Halligan Project will require the relocation of approximately 27
overhead power poles and lines from the southwest end of the exiting
reservoir to the new dam since the old power poles would be
inundated during the Halligan enlargement. The existing poles and line
are too old to be reused safely. The new poles and line will be
constructed and energized prior to the removal of the old poles and
line. Installation and the removal of the overhead power line and poles
will result in temporary disturbance of vegetation due to vehicles
driving off-road. At this time, a formal access road is not being
proposed for the installation or removal of the overhead power lines
and poles. Some vegetation will be permanently removed to for the
placement of the new poles.
Fort Collins will work with Poudre Valley Rural Electric Authority to
perform raptor and migratory nesting bird surveys (Section 4.2.3.4,
Migratory Bird and Raptor Surveys) prior to construction. In addition,
construction BMPs (Section 4.2.3.7, Best Management Practices)
including sediment control and aquatic nuisance species measures
(Section 4.2.3.16, Aquatic Nuisance Species), and construction
disturbance minimization and reclamation measures (Section 4.2.3.9,
Construction Disturbance Minimization and Reclamation) will be
implemented. Installation and removal of the overhead power lines
and pole will be prohibited between December 1 and April 30. The
overhead power lines and poles will follow design guidelines similar
to those used by the Avian Power Line Interaction Committee and
will have bird diverters.
$0 $0
Avoidance
and
Minimization
Mitigation
Measures
Halligan Reservoir
Sediment Management
Plan
4.2.4 Operating the reservoir, particularly at low water levels, in accordance
with a plan developed by sediment experts is intended to avoid adverse
sediment release events.
A sediment management plan will be developed for Halligan
Reservoir that will provide guidelines for post-construction reservoir
operations (including low water level operations). CPW will be given
an opportunity to comment on the draft sediment management
plan.
$75,000 $0
EXHIBIT A TO RESOLUTION 2025-083
Measurement
Type
Mitigation, Monitoring,
and Enhancement
Measure
FWMEP Section Purpose for Measure Description of the Commitment[a] Fort Collins
Total
Capitalized
Cost[b]
FWMEP
Capitalized
Cost[b]
Compensatory
Mitigation
Measures
Preservation as Early
Compensatory Mitigation
Measure
4.3.1 In 2003 to 2004, as an act of early mitigation in anticipation of the
Halligan Project, Fort Collins led the purchase and preservation of a
permanent conservation easement of a 4,557-acre property known as
Roberts Ranch, which comprises several disconnected parcels (Figure 4
8) in the Livermore Valley. The easement covers 4,557 acres of high-
quality wildlife habitat and rangelands near Halligan Reservoir and is
also adjacent to 14,000 acres of other state and locally protected lands.
This early conservation effort provides the following benefits:
Direct and indirect ecological benefit to wildlife resources affected
by the Halligan Project, including long-term preservation of
suitable habitat for big game ungulates, as well as the federally
and state threatened Preble’s meadow jumping mouse and the
federally threatened Ute ladies’-tresses orchid
Land preservation and conservation in perpetuity of habitat for
wildlife and rare and native plants, and conservation of the
diverse forest, shrubland, meadow, and riparian vegetative
communities
Approximately 2 decades of land preservation before disturbance
from the Halligan Project construction activities
Preservation of areas within the linkage area for the Lone Pine
bighorn sheep herd where individual rams have been observed
annually by local residents from approximately March to October
on parcels of Roberts Ranch east of Highway 287 (Thode, pers.
comm. 2021), and limitations on grazing such that species other
than cattle or horses cannot be grazed on the property unless
approved by The Nature Conservancy in areas where use of cattle
or horses is impractical
Conservation of more than 8.8 miles of perennial streams
Direct connectivity to 14,000 acres of adjacent state and locally
protected lands
$1,800,000 $0
Compensatory
Mitigation
Measures
Fish Passage at the Fort
Collins Intake at Gateway
Park
4.3.2 The majority of diversions related to the Halligan Project will take place
at the Fort Collins’ Intake at Gateway Park on the Main Stem. This
diversion structure is located approximately 0.5 mile upstream of the
confluence with the North Fork. The diversion structure currently acts
as a barrier to fish movement, preventing the migration of fish past the
structure. With this action, Fort Collins will compensate for reduction of
flows on the Main Stem in the Exchange Reach between the Fort Collins
Intake(s) and the North Fork confluence.
Fort Collins will construct fish passage around the Fort Collins Intake
diversion structure at Gateway Park to increase connectivity for trout
and other large-bodied fish species on the Main Stem and to
compensate for impacts on Main Stem fisheries associated with flow
changes as a result of the Halligan Project. The fish passage will be
designed, in consultation with CPW, and to CPW’s Research and
Design Guidelines, Fish Passage and River Structures to provide
reliable upstream fish passage and will help to provide additional
connectivity upstream of the Fort Collins Intake.
Construction of this project will be completed prior to Fort Collins
beginning Halligan operations that involve exchanges on the Main
Stem or on an alternate timeline that is agreed upon between CPW
and Fort Collins.
$1,210,200 $1,210,200
EXHIBIT A TO RESOLUTION 2025-083
Measurement
Type
Mitigation, Monitoring,
and Enhancement
Measure
FWMEP Section Purpose for Measure Description of the Commitment[a] Fort Collins
Total
Capitalized
Cost[b]
FWMEP
Capitalized
Cost[b]
Compensatory
Mitigation
Measures
Bighorn Sheep Mortality
Compensation
4.3.3 Fort Collins will avoid and minimize potential Project effects on bighorn
sheep through the habitat improvements and movement tracking
collaring study described in Sections 4.2.3.17, 4.2.3.18, 4.2.3.19 and
through construction timing restrictions described in Section 4.2.3.13.
Additional construction-related measures to avoid and minimize
impacts on terrestrial wildlife, including bighorn sheep, are described in
Section 4.2.3.7. If, despite these efforts, construction of the Halligan
Project causes mortality directly, through euthanasia or otherwise, to
bighorn sheep in the Lone Pine herd, Fort Collins will offset this
unavoidable impact through monetary compensation to CPW.
Fort Collins will provide monetary compensation of $7,300 per sheep
to CPW for any Lone Pine herd bighorn sheep that experience
mortality during project construction and 2 years postconstruction.
Although not all mortality experience during the construction period
is anticipated to be caused by the Project, as a conservative
approach Fort Collins is willing to assume that mortalities during the
construction period and 2 years postconstruction will be
compensated. Additionally, if Lone Pine herd mortalities are
observed in the 2 years following the end of construction, Fort
Collins will compensate CPW $7,300 per sheep. CPW has concerns
that the Halligan Project construction may cause Lone Pine herd
sheep to change movement patterns such that they act as a vector
for disease transmission from domestic sheep to the Lower Poudre
herd. Fort Collins will work with CPW to develop an adaptive
management approach to monitoring bighorn sheep movements to
assess disease transmission, and will compensate CPW for Lower
Poudre herd bighorn sheep that were exposed to respiratory disease
because of the Halligan Project during and 2 years after construction.
$0 $0
Compensatory
Mitigation
Measures
Compensatory Mitigation
for Halligan Project
Impacts on Stream
Temperature
4.3.4 The restoration will be focused on either enhancing aquatic life habitat
or funding a fish passage project, or both. This money is committed as a
compensatory mitigation for unavoidable temperature impacts on the
Main Stem.
Fort Collins will commit $200,000 of funding for stream restoration
efforts along the Main Stem, or North Fork, within or near the
Halligan Project Area, including the North Fork above Halligan
Reservoir to compensate for potential project-related temperature
increases. Fort Collins and CPW will have final approval authority on
any use of funds and will be used for the public benefit.
Note: This commitment is separate from the $200,000 enhancement
commitment for the North Fork described in Section 5.1.1.6;
however these funding commitments may be combined or used
independently.
$200,000 $200,000
Compensatory
Mitigation
Measures
Compensatory Mitigation
for Halligan Project
Impacts on Wetlands
4.3.5 Wetland mitigation for Halligan Project impacts may include
restoration, mitigation banking, or other measures that benefit fish and
wildlife.
Compensatory mitigation and monitoring for wetlands will be
described in a separate mitigation plan yet to be developed for
approval by the Corps.
$2,490,400 $0
Compensatory
Mitigation
Measures
Special Status Species 4.3.6 Fort Collins seeks to avoid and minimize any adverse impacts on any
special-status species. Halligan Project mitigation measures, such as the
preservation of Roberts Ranch (Section 4.3.1), and the numerous
avoidance and minimization measures (Section 4.2) will adequately
mitigate potential Halligan Project effects on state-listed species. This
applies for all of Section 4.3.6 except for Section 4.3.6.1 discussed in
the next row.
No additional species-specific compensatory mitigation measures
have been proposed.
Although Fort Collins' mitigation actions directed towards special
status species (e.g., Preble's meadow jumping mouse) will benefit
other fish and wildlife, no costs are included here since they are
considered in the Preservation as Early Compensatory Mitigation
Measure.
$0 $0
Compensatory
Mitigation
Measures
Preble's Meadow Jumping
Mouse Habitat
Improvements/Monitoring
Contribution
4.3.6.1 Mitigation and monitoring of Halligan Project impacts on Preble’s are
being developed in consultation with USFWS.
Mitigation and monitoring of Halligan Project impacts on Preble’s are
described in the Halligan Water Supply Project Preble’s Meadow
Jumping Mouse Mitigation Plan.
$218,900 $0
EXHIBIT A TO RESOLUTION 2025-083
Measurement
Type
Mitigation, Monitoring,
and Enhancement
Measure
FWMEP Section Purpose for Measure Description of the Commitment[a] Fort Collins
Total
Capitalized
Cost[b]
FWMEP
Capitalized
Cost[b]
Compensatory
Mitigation
Measures
Recreational Resources 4.3.7 The surface of Halligan Reservoir is not open to the public for
recreational use, the Halligan Project will not change the public’s ability
to recreate on the reservoir.
The enlarged Halligan Project Reservoir will inundate approximately a
0.75-mile reach of the North Fork upstream of the existing Halligan
Reservoir, resulting in the loss of approximately 20 acres of potential
hunting lands and river fishing along a 0.4-mile stretch of this reach.
The proposed mitigation measure are discussed in detail in the next
three rows relating to Sections 4.3.7.1, 4.3.7.2, and 4.3.7.3.
Fort Collins understands CPW’s desire to see public angling access at
the enlarged Halligan Reservoir. Since the Halligan Project is not
impacting surface water recreation at Halligan Reservoir, Fort Collins
and CPW have agreed to continue discussions related to recreational
opportunities at the enlarged Halligan Reservoir in a process
separate from the current processes to enlarge Halligan Reservoir
and the FWMEP. To formalize this commitment, Fort Collins will
include language in an intergovernmental agreement with CPW to
continue discussions related to recreation at the enlarged Halligan
Reservoir. Those discussions may include the reservoir being
managed for recreation by CPW as a part of the Cherokee SWA.
If, separate from the current processes to enlarge Halligan Reservoir,
the reservoir is opened to public recreation at a point in the future,
any recreation plan proposed by Fort Collins that will affect the
Cherokee SWA will be developed in conjunction with CPW and will
consider impacts on fish and wildlife habitat, including impacts on
any access through the Cherokee SWA. The recreation plan will also
consider and compensate for the resource needs for CPW to stock
and manage Halligan Reservoir for public angling access, if CPW
determines it will maintain a public fishery.
$0 $0
Compensatory
Mitigation
Measures
Reconciliation of Title
Chain Confusion
4.3.7.1 Fort Collins discovered that approximately 39 acres of land in the
eastern half of Section 29 and in the northeastern quarter of Section 32
that were thought to be owned by CPW are owned by Fort Collins and a
private party. Upper portions of the enlarged Halligan Reservoir will be
located on portions of these lands. For the most part, these lands are
surrounded by the Cherokee SWA–Middle Unit and according to CPW,
these lands have been accessed by the public for over 50 years20. Fort
Collins intends to acquire these lands for the enlarged Halligan
Reservoir.
After acquiring these lands, Fort Collins will seek an agreement with
CPW to convey an easement to CPW across these lands for public
use, provided that the surface of the enlarged reservoir will not be
opened to public access at this time. Any such agreement and
conveyance will be subject to applicable laws, including statutes
applicable to CPW, and the Fort Collins Municipal Code Chapter 23
(Public Property), Article IV (Disposition of Property), Division 2 (Real
Property).
$0 $0
Compensatory
Mitigation
Measures
Funding of Public Access
Lease with Roberts Ranch
4.3.7.2 The Krause Field parcel was conserved as a part of the Roberts Ranch
conservation easement secured by Fort Collins and partners in 2003
and 2004 (refer to Section 4.3.1). CPW has been pursuing a lease
allowing primitive foot access for hunting and fishing on the Krause
Field parcel. Fort Collins understands that this lease will provide public
access to over 2,200 acres of hunting and approximately 1 mile of river
access and fishing, which includes the North Fork and potentially
stretches of its tributaries, Dale Creek and Bull Creek.
Fort Collins will contribute funding to CPW to support a lease of the
Krause Field parcel of Roberts Ranch. Fort Collins agrees to a one-
time reimbursement in the amount of $135,000 for CPW to pursue a
long-term lease (in process) of the Krause Field parcel.
$135,000 $135,000
20 Fort Collins is evaluating if and the extent to which the public has accessed this part of the inundation area and makes no representations on this issue.
EXHIBIT A TO RESOLUTION 2025-083
Measurement
Type
Mitigation, Monitoring,
and Enhancement
Measure
FWMEP Section Purpose for Measure Description of the Commitment[a] Fort Collins
Total
Capitalized
Cost[b]
FWMEP
Capitalized
Cost[b]
Compensatory
Mitigation
Measures
Parking Area
Establishment at State
Wildlife Area
4.3.7.3 An existing primitive parking area near the southwest portion of
Halligan Reservoir is located on Fort Collins’ property in the northeast
quarter of Section 32. The parking area falls within an area previously
thought to be owned by CPW. This parking area will be inundated by
the enlarged Halligan Reservoir.
Fort Collins will provide $30,000 in funds to create a new parking
area on CPW land outside of the inundation area, to provide
comparable access to this general location. The new parking area will
be primitive and similar in form to the existing parking area.
$30,000 $0
Compensatory
Mitigation
Measures
Instream Water Rights 4.3.8 The enlarged Halligan Reservoir will inundate approximately 0.75 mile
of the North Fork upstream of the current reservoir where the CWCB
holds an instream flow water right.
Because of the additional stream flow that will be provided
downstream, Fort Collins’ commitment to protect those associated
releases from Halligan Reservoir for approximately 22 miles
downstream using the Protected Mitigation Release statute (CRS 37-
92-102[8]), and the aquatic resource enhancements described in
Section 5, no additional compensatory mitigation is proposed for
impacts on the CWCB’s instream flow water rights as part of this
FWMEP.
$0 $0
Monitoring
and Adaptive
Management
for Mitigation
Streamflow Monitoring 5.3.1 Streamflow monitoring data will enhance the existing dataset that is
available for public use and will also be used by Fort Collins to help
inform operational decisions for the enlarged Halligan Reservoir.
Fort Collins has already installed one of two new North Fork
streamflow gages associated with the Halligan Project. The first gage,
located above the future inlet of the enlarged Halligan Reservoir, was
installed by Fort Collins in fall 2020 in coordination with the United
States Geological Survey. An existing stream gage is located below
the Halligan Dam that will remain in the future. The second gage will
be installed by Fort Collins at or below the bypass channel to be
constructed on the North Poudre Canal Diversion to monitor
streamflow and inform North Poudre Canal Diversion and Halligan
Reservoir operations. In addition, Fort Collins will also rely on the
existing Livermore gage located where the North Fork crosses
West County Road 74E.
$2,487,200 $0
Monitoring
and Adaptive
Management
for Mitigation
Sediment,
Macroinvertebrate, and
Water Quality Monitoring
5.3.2 Sampling for sediment and macroinvertebrates, downstream of
Halligan Reservoir will help monitor sediment relative to standards and
identify any new impairment or worsening conditions. This information
can be used to determine appropriate response actions per the
sediment management plan, as needed. Fort Collins will also monitor
iron immediately below the enlarged reservoir for 5 years to determine
if the flushing event (described in Section 4.2.1.6) is effective and/or
necessary. If a MLOW is installed (described in Section 4.2.2.1), real-
time oxygen and temperature data from multiple elevations in Halligan
Reservoir during summer months will be needed to support operational
decision-making for the MLOW.
This sediment sampling will continue for a period of 5 years following
the build out of Halligan Project operations, after which time the
need to continue sampling will be reconsidered in coordination with
CPW and WQCD.Iron monitoring will consist of visual checks for iron
deposition on sediment in the vicinity of the NBH sampling station
(and photographic records of any observed deposition) as well as
continued sampling at NBH for dissolved and total iron. However, if it
is determined at the end of the first 5 years following construction
(in consultation with CPW) that this operation is no longer needed,
then the releases and special monitoring (observations of iron
deposition) will end.If a MLOW is installed (described in Section
4.2.2.1), real-time oxygen and temperature data from multiple
elevations in Halligan Reservoir during summer months would be
used to help manage water quality of releases to the North Fork with
an MLOW. As such, this monitoring will be conducted as a critical
component of the MLOW mitigation element.
$120,000 $120,000
EXHIBIT A TO RESOLUTION 2025-083
Measurement
Type
Mitigation, Monitoring,
and Enhancement
Measure
FWMEP Section Purpose for Measure Description of the Commitment[a] Fort Collins
Total
Capitalized
Cost[b]
FWMEP
Capitalized
Cost[b]
Monitoring
and Adaptive
Management
for Mitigation
Adaptive Management
Costs
Various Measures Adaptive management in response to environmental monitoring is
indirectly incorporated into some mitigation and enhancement
measures in the FWMEP, including the MLOW, bighorn sheep collaring
and mortality compensation, sediment management, and temporary
environmental pool measures.
This measure will help with aquatic and terrestrial species and
ecosystems by monitoring and adapting plans accordingly.
The FWMEP capitalization cost of $37,500 is for adaptive
management related to bighorn sheep.
$225,000 $37,500
Monitoring
and Adaptive
Management
for Mitigation
Bighorn Sheep Collaring
Study
5.3.3 Collaring and tracking of the Lone Pine herd will be conducted before,
during, and after the Halligan Project construction.
The commitments are captured in the avoidance and minimization
mitigation measures described in Section 4.2.3.18 and the
compensatory mitigation measure described in Section 4.3.3.
$0 $0
Enhancement
Measures
Temporary Environmental
Pool
5.1.1.1 Between the time that Halligan Reservoir is enlarged and the time
when Fort Collins grows into its future demand levels associated with
the Halligan Project, Fort Collins will dedicate an annually variable
storage volume in the enlarged Halligan Reservoir to release for
environmental benefits downstream. This annually variable volume of
water dedicated for environmental benefits is referred to as the
temporary environmental pool (TEP).
The purpose of the TEP is to enhance the environmental benefit, or
functional lift, of the flow-related operational measures described in
Section 4.2.1. The primary objective of the TEP is to positively affect
stream health in the North Fork from the replacement Halligan Dam to
Seaman Reservoir. In general, the TEP will be used to benefit whole
stream health, with the ability to focus on specific river functions, or
single-species management in select years. Use of the TEP will be
informed by first principles of river ecology.
Fort Collins will determine the volume of water available for the TEP
each year. Volumes in the range of 500 to 1,000 acre-feet are
expected to be available; however, the actual volume available could
increase or decrease after information is gained from the first several
years of operation of the enlarged Halligan Reservoir.
Decisions regarding the volume of water allocated each year will be
made by Fort Collins. The volume and targeted window for releases
will be determined before July 1 each year. The window for releases
will typically be from July 1 to the following April 30.
Fort Collins will not re-divert the TEP releases until after they have
reached the confluence with the Main stem of the Poudre River. The
primary stakeholders for the TEP will be Fort Collins and CPW.
The best use of this water will be determined based on decreed
beneficial uses of the water rights and current conditions at that
point in time and the greatest ecological concerns or issues, with one
of the priorities being management of small bodied native fish
species downstream of Halligan Reservoir. Operational targets for
use of the TEP could be set for several years at a time to address
multiple ecological priorities.
NPIC cannot divert the TEP releases into the North Poudre Canal
pursuant to an existing agreement with Fort Collins.
$150,000 $0
Enhancement
Measures
Joint Operations 5.1.1.2 Fort Collins will continue to entertain opportunities for operational
synergies with other managed water deliveries in the Poudre River
watershed in order to potentially provide targeted benefits to the
watershed.
Potential enhancement to environmental benefits related to stream
flows.
$0 $0
EXHIBIT A TO RESOLUTION 2025-083
Measurement
Type
Mitigation, Monitoring,
and Enhancement
Measure
FWMEP Section Purpose for Measure Description of the Commitment[a] Fort Collins
Total
Capitalized
Cost[b]
FWMEP
Capitalized
Cost[b]
Enhancement
Measures
Fish Passage at the
Reconstructed North
Poudre Canal Diversion
5.1.1.3 North Poudre Canal Diversion is approximately 6 miles downstream of
Halligan Reservoir on the North Fork. The structure currently acts as a
barrier to upstream fish passage, preventing the migration of fish past
the structure.
Fort Collins will reconstruct the North Poudre Canal Diversion so that
Fort Collins’ releases can be bypassed by that structure and remain in
the North Fork. To provide increased connectivity for small-bodied
native species and trout in the North Fork, Fort Collins will
incorporate fish passage into or around the reconstructed North
Poudre Canal Diversion, in the form of a fish ladder, bypass channel,
or other infrastructure. Fish passage will be designed, in consultation
with CPW, and to CPW’s Fish Passage and River Structures Research
and Design Guidelines to provide reliable fish passage at the North
Poudre Canal Diversion and connect an extensive reach of the North
Fork. Fish passage construction will happen concurrently with
reconstruction of the North Poudre Canal Diversion, in accordance
with the timeline listed in Figure 4-7, will be completed by the time
Fort Collins begins storing water in the enlarge Halligan Reservoir or
an alternate timeline that is agreed upon between CPW and Fort
Collins.
$1,759,750 $0
Enhancement
Measures
Channel Improvements
and Modifications of the
Calloway Diversion
5.1.1.4 The Calloway Diversion is located on the North Fork approximately
7.5 river miles downstream of Halligan Reservoir. The diversion is no
longer used. Although water passes the structure, it acts as a barrier to
fish passage, preventing the migration of fish past the structure.
Fort Collins will pursue an agreement in good faith with the
landowners and other stakeholders to complete this project. A
preliminary concept was developed in collaboration with
landowners, CPW, and other stakeholders, includes removal of the
center portion of the structure, while leaving the sidewalls of the
structure in place. This project will be constructed in accordance with
the timeline listed in Figure 4-7 and will be completed by the time
Fort Collins begins storing water in the Halligan Reservoir Expansion
or an alternate timeline that is agreed upon between CPW and Fort
Collins. If Fort Collins is unable to come to an agreement with the
landowners to complete channel improvements and modifications of
the Calloway Diversion within the timeline that aligns with the
reconstruction of the North Poudre Canal Diversion discussed in
Section 5.1.1.3, Fort Collins will coordinate with CPW and the
landowners to discuss an alternative timeline to avoid or minimize
impacts to bighorn sheep as discussed in Sections 4.2.3.13, 4.2.3.17,
and 4.2.3.19.
The improvements at the Calloway Diversion will have the largest
impact on aquatic habitat; however, the improvements will also
benefit terrestrial species, specifically Preble’s. The USFWS considers
the Calloway Diversion to be a habitat filter to Preble’s movement.
The removal of the diversion will reconnect the Preble’s habitat.
$1,120,645 $0
Enhancement
Measures
Ramping Rate Limitations
for NPIC’s Pool in an
Enlarged Halligan
Reservoir
5.1.1.5 The ramping rate limitations described in Section 4.2.1.2 apply only to
Fort Collins’ operation of its portion of the enlarged Halligan Reservoir;
they do not apply to operation of NPIC’s portion of the reservoir.
Fort Collins will commit to making a good faith effort to reach an
agreement with NPIC to adhere to the same ramping rate limitations.
Previous discussions with NPIC indicate that it would prefer to
explore any such commitments after the enlarged reservoir is
operational for several years.
$0 $0
EXHIBIT A TO RESOLUTION 2025-083
Measurement
Type
Mitigation, Monitoring,
and Enhancement
Measure
FWMEP Section Purpose for Measure Description of the Commitment[a] Fort Collins
Total
Capitalized
Cost[b]
FWMEP
Capitalized
Cost[b]
Enhancement
Measures
North Fork Stream
Restoration
5.1.1.6 Fort Collins will commit to provide funding for stream restoration
efforts along the North Fork. The restoration will be focused on either
enhancing habitat for small-bodied native fish or salmonids.
Fort Collins will commit $200,000 of funding for stream restoration
efforts along the North Fork, or Main Stem, within or near the
Halligan Project Area, including the North Fork above Halligan
Reservoir. This commitment is separate from the $200,000
mitigation commitment for the Main Stem described in Section 4.3.4;
these funds may be combined or used independently. Fort Collins
and CPW will have final approval authority on any use of funds and
will be used for the public benefit.
$200,000 $200,000
Enhancement
Measures
Bottom Release from
Halligan when Spilling
5.2.1.1 Water will be released from Halligan Reservoir through the bottom
outlets at times when the reservoir is spilling over the dam. Avoiding
buildup of sediment behind the dam should, in part, help avoid an
adverse sediment release event like the one that occurred because of
operations in 1996.
Thermal shock can occur below the Halligan Reservoir dam under
current Halligan Reservoir dam operations. The Halligan Project has an
inherent benefit of reducing the current frequency of thermal shock
below Halligan Reservoir dam because no spilling is anticipated (per
DEIS flow modeling) to occur in summer or fall months (that is, at times
when the reservoir is thermally stratified).
Bottom release should allow for reduced retention of sediment in
Halligan Reservoir, allowing for appropriate sediment transport
downstream to the North Fork.
This measure is also considered a voluntary enhancement in terms of
river temperature for its parallel benefits in reducing the risk of
thermal shock below the Halligan Reservoir dam. Bottom releases
during spilling would provide further enhancement in terms of
further reducing the risk of thermal shock because such releases
would serve to blend top and bottom temperatures, minimizing the
sharp temperature change in releases, in the unanticipated event
that the reservoir does spill at a time of thermal stratification with
the Halligan Project.
$0 $0
Enhancement
Measures
Passive Aeration in Outlet
Structure
5.2.2 Fort Collins will incorporate design measures for the replacement
Halligan Dam that passive physical aeration. This will increase dissolved
oxygen concentrations in water released to the North Fork, enhancing
conditions for aquatic life immediately below the reservoir. This
aeration will be applied to releases from both Fort Collins’ and NPIC’s
portion of the enlarged Halligan Reservoir.
Because adverse impacts on aquatic life are not anticipated in terms
of oxygen below Halligan Reservoir, inclusion of passive aeration in
the outlet structure is considered to be a voluntary enhancement, as
opposed to mitigation. Design measures being evaluated that would
increase DO include an updated stilling basin, a stepped spillway, and
a turbulent discharge area with energy dissipation. This aeration will
be applied to releases from both Fort Collins’ and NPIC’s portion of
the enlarged Halligan Reservoir.
$0 $0
Enhancement
Measures
Prohibition of Domestic
Sheep and Goat Grazing
on City-owned Lands Near
Halligan Reservoir
5.2.3.1 Several land managers within the Lone Pine herd-occupied range along
or near key components of the Halligan Project use domestic sheep to
control larkspur (Delphinium species), which are toxic to cattle.
Although domestic sheep can be an effective vegetation management
tool, this practice increases the chances of commingling between the
Lone Pine herd and domestic sheep. The greatest concern of such
commingling is the transmission of deadly pathogens between
domestic sheep and goat populations and populations and the Lone
Pine herd.
As a measure to help reduce the long-term risk of disease
transmission, soon as this FWMEP is approved, Fort Collins will:
Permanently stop grazing domestic sheep or goats for weed
control or other purposes on any Fort Collins-owned lands around
Halligan Reservoir
Will not enter into grazing leases that would authorize others to
graze domestic sheep or goats on any Fort Collins-owned lands
around Halligan Reservoir
Will not grant licenses or convey easements authorizing domestic
sheep or goats to graze on any Fort Collins-owned lands around
Halligan Reservoir
$0 $0
EXHIBIT A TO RESOLUTION 2025-083
Measurement
Type
Mitigation, Monitoring,
and Enhancement
Measure
FWMEP Section Purpose for Measure Description of the Commitment[a] Fort Collins
Total
Capitalized
Cost[b]
FWMEP
Capitalized
Cost[b]
Enhancement
Measures
Advocate for Cessation of
Domestic Sheep and Goat
Grazing on Private Lands
Near Halligan Reservoir
5.2.3.2 Landowners near the Halligan Project Area periodically allow domestic
sheep and goat grazing on their property to control larkspur, which are
toxic to cattle and horses. Comingling of domestic sheep and goats with
bighorn sheep is linked to disease transmission to bighorn sheep, which
can result in bighorn sheep mortality.
Fort Collins will engage with local landowners to advocate for both
the temporary cessation of domestic sheep and goat grazing during
construction, as well as for the permanent cessation of domestic
sheep and goat grazing near the Halligan Project Area. Ceasing
domestic sheep and goat grazing on private property around the
Halligan Project Area will avoid the potential for disease transmission
from domestic sheep and goats to bighorn sheep.
$0 $0
Not
Applicable
Not Applicable Not Applicable Not Applicable Mitigation $15,345,903 $2,958,650
Not
Applicable
Not Applicable Not Applicable Not Applicable Monitoring and Adaptive Management $2,832,200 $157,500
Not
Applicable
Not Applicable Not Applicable Not Applicable Total Mitigation, Monitoring and Adaptive Management Cost $18,178,103 $3,116,150
Not
Applicable
Not Applicable Not Applicable Not Applicable Enhancement $3,230,395 $200,000
Not
Applicable
Not Applicable Not Applicable Not Applicable Total Mitigation and Enhancement Costs for Project $21,408,498 $3,316,150
Not
Applicable
Not Applicable Not Applicable Not Applicable Total Design and Construction Costs (Per 30% Design) $144,584,000 Not Applicable
[a] The description of mitigation commitments is at a summary level - see text for details of the commitment. The text shall take precedent over any discrepancies between this table and the text.
[b] Capitalized cost is the sum of the capital cost plus any annual operations and maintenance costs capitalized over the life of the commitment, or 50 years for those commitments that are perpetual.
EXHIBIT A TO RESOLUTION 2025-083
Appendix C
Surface Water Quality Supplemental Information
EXHIBIT A TO RESOLUTION 2025-083
Appendix C. Surface Water Quality Supplemental
Information
This appendix presents an overview of surface water quality current conditions for Halligan Reservoir,
Seaman Reservoir, the North Fork, and the Main Stem. This appendix is intended to be a high-level
summary and is not intended to fully recreate documentation of the studies/communications
referenced (Hydros 2020, 2021a, 2021b, 2021c, and 2021d, 2022a, 2022b, and 2022c). Instead,
highlights of the key findings regarding current surface water-quality conditions are presented, by area.
The referenced studies rigorously document the conceptualization of existing major drivers of spatial
and temporal variability in temperature and water quality in Halligan Reservoir, Seaman Reservoir, the
North Fork, and the Main Stem. The conceptual understanding in those documents is based on
evaluation of observed water-quality data, flow data, diversion patterns, reservoir operations, geology,
point sources, land use, and spatially varying meteorological conditions. Observed data were also
compared in these studies to applicable aquatic life water-quality standards to identify existing concerns
relative to standards. Sampling stations considered in those analyses and referenced in this appendix are
presented in Appendix D, Water Quality Sampling Location Maps. Additionally, Appendix D is supported
by two memoranda (Hydros 2022a and Hydros 2022c).
C.1 Halligan Reservoir
Current conditions in Halligan Reservoir are discussed in Hydros (2020, 2022a, and 2022c) and
summarized briefly here. Halligan Reservoir is currently an approximately 6,400 acre-feet, on-channel,
water supply reservoir on the North Fork. The reservoir is relatively shallow except near the dam
(Figure C-1). The annual residence time is relatively short, averaging roughly 26 days (based on observed
data from 2010 to 2018). Monthly residence times tend to be relatively low (fewer than 30 days) from
April through October and higher in winter months of November through March (Figure C-2). This
reflects the typical seasonal inflow and release patterns. Inflows into the reservoir follow a typical
pattern of high flows during spring snowmelt runoff and declining flows through the summer. The
reservoir fills in the winter and the timing of full pool can vary by year, sometimes filling as early as the
end of December and sometimes not filling until the end of May. The reservoir stratifies each year,
generally from May to August, with the duration of stratification being limited by strong winds and
reservoir operations that draw down water levels during summer. Water can be released via outlet
works at the bottom of the reservoir and/or at the spillway (when the reservoir is full).
EXHIBIT A TO RESOLUTION 2025-083
Figure C-1. Bathymetric Map of Halligan Reservoir (Based on 2003 Survey) at Existing Full Pool
Figure C-2. Average Monthly Residence Time in Halligan Reservoir (Based on Observed Release Rates
and Storage Volumes from 2010 to 2018)
For most constituents, inflow concentrations to Halligan Reservoir peak during spring runoff and then
decline. While the reservoir is stratified during summer, the hypolimnion can become hypoxic
(≤ 2 milligrams per liter [mg/L] dissolved oxygen [DO]; Figure C-3) and internal loading of redox-sensitive
constituents from the sediments is observed. Chlorophyll a concentrations tend to be relatively low,
averaging 6 micrograms per liter [µg/L] for July through September (2016 to 2019). The maximum
observed chlorophyll a concentration in Halligan Reservoir (2016 to 2019) is 13.3 µg/L
(November 8, 2016; Figure C-4).21 The reservoir is not on the current CWA Section 303(d) list or the
21 Note that the sampling stations considered in the development of the understanding of current conditions for surface water quality are
mapped in Appendix D.
EXHIBIT A TO RESOLUTION 2025-083
Monitoring and Evaluation list for any constituents (WQCC 2021b) because the data were not previously
shared with WQCD; however, a comparison of observed data to applicable aquatic life water-quality
standards and interim nutrient criteria (WQCC 2020) indicates possible current in-reservoir concerns for
dissolved silver, water temperature, and total phosphorus.
Figure C-3. Dissolved Oxygen Profiles in Halligan Reservoir (2021)
Figure C-4. Observed Chlorophyll a Concentrations in Halligan Reservoir (2016 to 2019)
EXHIBIT A TO RESOLUTION 2025-083
C.2 Seaman Reservoir
Current conditions in Seaman Reservoir are described in detail in Hydros (2021b) and briefly
summarized in this section. Seaman Reservoir is a 4,150 acre-feet,22 on-channel water supply reservoir
on the North Fork operated by the City of Greeley located 22 miles downstream of Halligan Reservoir.
The average annual residence time (2008 to 2019) is 45 days. Inflows to the reservoir primarily occur
during spring runoff and enter the reservoir via the North Fork. Because the reservoir is often full during
spring runoff, much of the spring runoff flow is passed through the reservoir and released to the North
Fork downstream. The reservoir is often drawn down during late summer and fall, and typically refills by
December. Water is released from outlet works at the bottom of the reservoir dam when pool levels are
below the spillway. Seaman Reservoir stratifies in the summer each year, with stratification typically
beginning early April or May and lasting until fall turnover in September or October. At times, water
quality below Seaman Reservoir has negatively impacted aquatic life, including a fish kill in August 2018
(Battige 2018).
Anoxia (0 mg/L DO) is routinely observed in the hypolimnion of Seaman Reservoir during summer
stratification (for example, Figure C-5), and the reservoir also periodically exhibits metalimnetic DO
minima (caused by the decay of settling organic matter; for example, the profile on June 25, 2019 on
Figure C-5). The seasonal reducing conditions in the hypolimnion cause internal release of nutrients and
metals from the reservoir sediment. Summer chlorophyll a concentrations are typically below 20 µg/L,
but major blooms have also occurred. For example, a cyanobacteria bloom occurred in 2012 exhibiting a
peak observed chlorophyll a concentration of 183 µg/L, and another bloom occurred in 2017, with a
peak observed chlorophyll a concentration of 100 µg/L.
Figure C-5. Example Dissolved Oxygen Profiles from Seaman Reservoir, 2019
22 Recent (2016) bathymetric surveys performed by TetraTech indicate the reservoir capacity is approximately 4,150 acre-feet, suggesting the reservoir
has lost approximately 850 acre-feet of storage to sedimentation since reservoir construction in 1941 (TetraTech 2018).
EXHIBIT A TO RESOLUTION 2025-083
Comparison of observed data from Seaman Reservoir to applicable aquatic life water-quality standards
(WQCC 2021a) indicates concerns with DO and temperature. In 5 of 11 years from 2008 to 2019, DO
concentrations were observed below the standard in the mixed layer following fall turnover (for
example, the profile on September 23, 2019 on Figure C-5). Seaman Reservoir is currently on the CWA
Section 303(d) list for DO (WQCC 2021b). There are also two years in the recent record (2017 and 2018)
that show temperatures in the mixed layer exceeding the applicable standard at a time when no
adequate refuge for fish existed at greater depth (e.g., 7/10/18 in Figure C-6).23 Given the anoxic
conditions in the hypolimnion during stratification and the bottom releases during summer, there may
also be issues relative to the aquatic life sulfide standard in and immediately below the reservoir,
though there are no sulfide data24 to verify this concern.
Figure C-6. Example Profile Pair from Halligan Reservoir Showing Temperature Exceedance and No
Adequate Refuge; July 10, 2018
Finally, observed data from Seaman Reservoir suggest concerns relative to the interim nutrient criteria
values (WQCC 2020) for chlorophyll a, total nitrogen, and total phosphorus. While the interim criteria
values have not been adopted as standards for the reservoir, concentrations in excess of the interim
values are observed in more than half of the years of record from 2008 through 2019.
23 Adequate refuge refers to layers in the water column where both temperature and dissolved oxygen are within their respective standards.
24 Note that the standard applies to undissociated sulfide, and there are no undissociated sulfide data.
EXHIBIT A TO RESOLUTION 2025-083
C.3 North Fork
Current conditions for surface water quality on the North Fork are discussed in detail in Hydros (2021b,
2022a, and 2022c) and summarized in this section. Water quality on the North Fork from Halligan
Reservoir to the confluence with the Main Stem is influenced by releases from Halligan and Seaman
Reservoirs, as well as seasonally by inflow water quality of tributaries and groundwater in the Livermore
Valley. Concentrations of many constituents tend to peak during spring runoff. There is notable
attenuation for some constituents, including nutrients and some metals, along the approximately
22 river miles from Halligan Reservoir to Seaman Reservoir, particularly in summer and winter months
(outside of the high-flow spring runoff period).
Current aquatic life water-quality concerns on the North Fork relative to standards are limited to
dissolved silver and water temperature. Additionally, CPW has expressed concern regarding total iron
concentrations, specifically below Halligan Reservoir, indicating that CPW believes the existing standard
is not adequately protective of aquatic life. Note that this iron aquatic life standard concern is specific to
CPW, and WQCD intends to focus on the existing aquatic life iron standard for the purposes of CWA
Section 401 water quality certification. Finally, there is an existing total maximum daily load (TMDL) for
sediment on the North Fork. The following paragraphs provide additional discussion regarding current
conditions on the North Fork for dissolved silver, water temperature, total iron, and sediment.
C.3.1 Dissolved Silver
Dissolved silver in the North Fork is on the current CWA Section 303(d) list (WQCC 2021b) because it
exceeds the hardness-based standard in some years (during spring runoff when hardness tends to be
low). Observations above standards are most frequent in the reaches above and below Halligan
Reservoir, though exceedances also occur farther downstream (Figure C-7). The timing and spatial
distribution in the silver data indicate that it is mobilized from the watershed by runoff. There are no
known metals mining or industrial activities in the watershed that could serve as an anthropogenic
source of the observed silver. Further, the extensive Halligan Reservoir dataset indicates that there is no
evidence suggesting the occurrence of internal loading of silver within the reservoir (Hydros 2022c).
Figure C-7. Hardness across the North Fork, 2016-2019
EXHIBIT A TO RESOLUTION 2025-083
C.3.2 Water Temperature
Current conditions for river temperature on the North Fork are discussed in detail in Hydros (2021d) and
summarized in this section. The reach of the North Fork below Seaman Reservoir is currently on the
CWA Section 303(d) list for temperature (WQCC 2021b); however, observed data indicate that there are
consistent issues relative to both the acute and chronic temperature standards across most of the North
Fork in summer months, typically July through September. There are no issues on the North Fork
relative to temperature standards outside of summer months with two exceptions. First, there are
occasional fall shoulder season issues below Seaman Reservoir, with conditions exceeding the acute and
chronic temperature standards in early November in some years. Second, sharp changes in water
temperature can occur downstream of the Halligan Reservoir dam (that is, thermal shock) at times when
the reservoir is thermally stratified and reservoir outflows switch from spilling of warmer water over the
dam to bottom releases of cooler water (for example, July 2017; Figure C-8). Such cases of unnatural
thermal shock can adversely affect aquatic life.
Figure C-8. Example of Thermal Shock below Halligan Dam (NBH), 2017
Red circle indicates observed sharp drop in river temperature due to switch from spilling over dam to bottom
releases.
Issues relative to temperature standards generally increase from upstream to downstream on the
North Fork in the summer months, as illustrated in the example dataset from July 2019 on Figure C-9
and Figure C-10. Summer temperatures tend to be coolest immediately below Halligan Reservoir (NBH),
reflecting bottom release temperatures, though the chronic temperature standard is still exceeded in all
years of record at NBH, with typical months of concern being July, August, and/or September. The rate
of warming along the North Fork is strongly influenced by meteorological conditions and flow rate,
including the effects of the North Poudre Canal Diversion, a major diversion located 6 river miles
downstream of Halligan Reservoir. Summer warming of river water is tempered somewhat through the
Livermore Valley by inflows from tributaries and groundwater gains (refer to NBP), which can comprise
the majority of flow in the North Fork below Lone Pine Creek from July through September
(Hydros 2021a). Below Seaman Reservoir on the North Fork (refer to NF-PRU) water temperatures can
be lower than those immediately upstream of Seaman Reservoir (refer to NSR) in early summer (for
example, July), but the opposite pattern is observed in later summer and early fall. On the North Fork
EXHIBIT A TO RESOLUTION 2025-083
below Seaman Reservoir, there are exceedances of both the acute and chronic summer standards in all
years of the observed record.
Figure C-9. Observed Weekly Average Temperatures across the North Fork on a Typical Summer Day
with Bottom Releases from Halligan Reservoir, 7/19/2019
°C = degree(s) Celsius
NBH, NFP, NPC, NCP, NSC, NBP, NEN, NSR, and NF-PRU are temperature sensor locations, and CS-II is the applicable
summertime temperature standard.
Weekly average temperature is a chronic temperature standard metric
Figure C-10. Observed Daily Maximum Temperatures across the North Fork on a Typical Summer Day
with Bottom Releases from Halligan Reservoir, 7/19/2019
Daily maximum is an acute temperature standard metric
C.3.2.1 Total Iron
Observed data indicate that there are no issues on the North Fork relative to the current aquatic life
standard for total iron (1,000 µg/L, assessed as an annual median); however, CPW has expressed
EXHIBIT A TO RESOLUTION 2025-083
concerns that the existing standard is not adequately protective.25 CPW cites Cadmus et al. (2018),
indicating that the chronic iron standard should be on the order of 251 µg/L, based on mesocosm tests.
While Fort Collins acknowledges that revision of the aquatic life iron standard may be appropriate, the
251 µg/L value from Cadmus et al. (2018) is not directly comparable to field measurements of total iron.
Assertion of a disconnect between field measurements of total iron and the 251 ug/L value is based on
the following: Cadmus et al. (2018) arrived at the 251 µg/L value through mesocosm studies applying
ferric chloride, which results in colloidal iron in solution. This form of iron is not directly comparable (in
terms of effect on aquatic life) to iron bound in suspended sediments, which would be included in total
iron lab analyses from field samples.
Net loading calculations indicate that Halligan Reservoir is a sink for iron. Inflow concentrations of both
total and dissolved iron peak during runoff. Data indicate that internal loading of iron from sediments
occurs in Halligan Reservoir during summer stratification due to reducing conditions in the hypolimnion.
Further, observed data indicate that a chronic standard value of 251 µg/L would not currently be met
upstream or downstream of the reservoir, or within Halligan Reservoir. This is the case for chronic total
or dissolved iron at 251 µg/L at any depth level in Halligan Reservoir (Table C-2).
Table C-2. Median and 85th Percentiles of Total Iron and Dissolved Iron Data
Site Years of Record Total Iron Median[a]
(µg/L)
Dissolved Iron 85th
Percentile[a] (µg/L)
NDC (North Fork above Dale Creek) 2016–2021 799 487
NAH (Halligan Reservoir inflow) 2020–2021 660 341
Halligan, top 2016–2021 377 318
Halligan, bottom 2016–2021 778 412
NBH (below Halligan Reservoir) 2016–2021 622 357
[a] These metrics are shown because water quality standards are typically assessed by comparing the median (for
total metals) or the 85th percentile (for dissolved metals) of the data to the standard value.
While chronic concentrations of total iron below Halligan Reservoir are currently greater than 251 µg/L,
there is currently no site-specific indication of aquatic life impairment on the North Fork because of iron,
though observations to date are not definitive. There have been no observations of iron coating of
sediments below the reservoir,26 which is an expressed concern of CPW regarding inhibition of
periphyton growth, benthic macroinvertebrates, and early life stage development of fish eggs.
Unfortunately, because of confounding factors, there is no direct approach to definitively determine on
a site-specific basis whether there is current impairment below Halligan Reservoir because of iron.
Multiple known aquatic life stressors on the system, including temperature and low flow rates, could
confound interpretation of the cause of any observed impairment.
25 While CPW has expressed concerns with the existing aquatic life standard for total iron, WQCD has made it clear that the existing standards will be the
basis for analysis in the HWSP 401 Certification Application, and 251 ug/L will not be considered in that analysis as an aquatic life standard for total
iron.
26 Sampler observations are limited to the reach between the dam and NBH (the sampling location approximately 600 feet below the dam). While NBH is
relatively close to the dam, it is expected to be far enough downstream to observed iron coating issues because dissolved oxygen concentrations at
this location are consistently at saturation.
EXHIBIT A TO RESOLUTION 2025-083
C.3.3 Sediment Total Maximum Daily Load
Currently, there is a sediment TMDL on the North Fork that extends from Halligan Reservoir dam to a
point 3.2 miles downstream. The TMDL was developed in 2002 (WQCC 2002) in response to a CWA
Section 303(d) listing of sediment for the reach because of a major sediment release event in 1996. The
sediment release event occurred at the time of a drawdown of the reservoir to allow for a safety
inspection of the dam and outlet structure. The 1996 sediment release resulted in severe adverse
impacts on fish and benthic macroinvertebrates in the North Fork in the 3.2 miles of river immediately
downstream of Halligan Reservoir.
There have been no observed damaging sediment releases from Halligan Reservoir since the 1996 event,
and recent data suggest sediment and aquatic life standards are currently being attained. Specifically,
pebble counts from 2020 indicate that percent fines are below the applicable threshold, and
macroinvertebrate data from 2019 and 2020 indicate that multimetric index values are above the
applicable attainment threshold. Macroinvertebrate data from 2020 also indicate that sediment
threshold indicator values (TIVSED) are below the applicable impairment threshold.
C.4 Main Stem
Water quality on the Main Stem over the approximately 60 river mile reach from the Munroe Canal
Diversion to the confluence with the South Platte River is influenced by many factors, including seasonal
snowmelt runoff, major tributary inflows, groundwater inflows, major diversions, treated wastewater
effluent, subsurface geology, and stormwater runoff. Current water-quality concerns on the Main Stem,
in terms of exceeding or approaching aquatic life standards, are limited to water temperature.
Additionally, observed concentrations of Total Nitrogen and Total Phosphorus are routinely above
interim nutrient criteria (WQCC 2020) in Segments 12a and 12b (from Prospect Road in Fort Collins to
the confluence with the South Platte River), though those criteria are not currently applicable standards.
Brief overviews of major temperature and non-temperature water-quality dynamics on the Main Stem
are provided in the following subsections. These discussions present major drivers of water-quality
response from upstream to downstream and provide information relevant to subsequent discussions of
anticipated Halligan Project impacts. Additional detail on spatial and temporal patterns and drivers of
water-quality in the Poudre River can be found in Hydros (2015, 2021a, 2021c, and 2021d).
C.4.1 Poudre River Temperature Dynamics
The Poudre River from the Munroe Canal Diversion to the Larimer County Canal (Segment 10a) is
currently on the CWA Section 303(d) list for temperature (WQCC 2021b) because of exceedances of the
chronic temperature standard. There are observations in excess of the chronic temperature standard in
summer months (July, August, and/or September) from the top of Segment 10a to just above the
Hansen Supply Canal inflow near the bottom of the segment. The frequency and magnitude of
exceedances of the chronic temperature standard increase from upstream to downstream across this
sub-reach of Segment 10a.
The rate of warming over Segment 10a above Hansen Supply Canal is exacerbated by major diversions,
the largest of which is the Munroe Canal Diversion. Inflows from the North Fork in this reach tend to be
notably warmer than the Main Stem during runoff months, summer months, and early fall. However,
the warming effect of the North Fork inflows on the Main Stem in summer months is limited, due to
relatively small flow rates from the North Fork. Finally, there is a dramatic shift in river temperature
below the inflow from Hansen Supply Canal near the bottom of Segment 10a (for example, Figure C-11
and Figure C-12). Hansen Supply Canal provides cooling water to the Main Stem, typically from May to
EXHIBIT A TO RESOLUTION 2025-083
October, in volumes significant enough to sharply reduce river temperatures (Bartholow 1991 and
Hawley et al. 2014), averaging 42 percent of the flow in the river below its point of entry from July
through September (Hydros 2021a). The cooling effect often reduces temperature from above the
chronic standard to well below the chronic standard. As a result, stream temperatures on the Main Stem
are less sensitive to small changes in flow rates downstream of Hansen Supply Canal on Segment 10a
and through Segment 10b.
Figure C-11. Weekly Average Temperatures on Select Summer Days in 2018 across the Main Stem
Focus Reach
Location of Hansen Supply Canal (HSC) inflow noted
Figure C-12. Daily Maxima on Select Summer Days in 2018 across the Main Stem Focus Reach
Location of HSC inflow noted
Below Hansen Supply Canal, summer river temperatures tend to increase moving downstream through
Segments 10b and 11. The rate of warming is increased primarily by major diversions in Segment 10b.
While temperature standards tend to be met in Segment 10b, the chronic temperature standard in
HSC Inflow
HSC Inflow
EXHIBIT A TO RESOLUTION 2025-083
Segment 11 (which was made more stringent in 2020) is routinely exceeded in summer months (July,
August, and/or September).
Farther downstream in Segments 12a and 12b, observed data exhibit no issues relative to acute or
chronic temperature standards. There is apparent warming in the Main Stem during summer months
(July, August, and September) near the upstream end of Segment 12a because of inflows from the Fossil
Creek Reservoir Outlet, which comprises a notable fraction of flow in the Main Stem immediately below
the outlet’s confluence with the river in summer months, averaging 15 percent of the flow from July
through September (Hydros 2021a).
Moving downstream of the Fossil Creek Reservoir Outlet, warming tends to be somewhat limited over
the remainder of Segments 12a and 12b (for example, Figure C-6 and Figure C-8). This is attributed to
the competing effects of warming from flow reductions by major diversions and cooling because of
groundwater return flows over the reach. Return flows include significant groundwater gains through
Segments 12a and 12b (Hydros 2021a). In these segments, groundwater tends to be cooler than the
river in summer months by 5°C to more than 10°C, providing a notable cooling effect on the river. There
is also a dampening of the diurnal temperature range across Segment 12a that is indicative of the
temperatures and magnitude of the groundwater inflows to the river (Hydros 2021a). There is an
apparent warming effect from Greeley wastewater treatment plant effluent (near the upstream end of
Segment 12b), typically observed in August and September; although temperature standards tend to be
met in the Main Stem below the effluent discharge location, temperatures routinely approach the
chronic standard. Downstream of the Greeley wastewater treatment plant, river temperatures exhibit
some cooling before entering the South Platte (for example, Figure C-6 and Figure C-8), reflecting
additional inflow of cooler groundwater.
C.4.2 Poudre River Non-temperature Water-quality Dynamics
There are currently no CWA Section 303(d) listings for aquatic life standards on the Main Stem from
Munroe Canal Diversion to the South Platte River, based on the most recent assessment of the Poudre
River in 2017 (WQCC 2021b). Still, to support consideration of potential effects of the Halligan Project, it
is important to understand several key drivers of water-quality in the Main Stem. A detailed conceptual
understanding of current water-quality dynamics on the Main Stem was developed based on observed
data and consideration of natural and anthropogenic flow patterns, geology, land use, point sources,
and non-point sources. Water-quality responses in the Main Stem follow many general patterns
expected for most river systems. For example, water quality in the Main Stem generally tends to
deteriorate from upstream to downstream, reflecting both natural and anthropogenic influences.
Additionally, as expected, nutrient and metals concentrations are observed to increase downstream of
treated wastewater effluent locations, particularly at times of lower flow in the Main Stem. This section
summarizes the observed influences of other current Main Stem water-quality drivers specific to the
Poudre River, including spring runoff, the North Fork, subsurface geology, and groundwater/agricultural
return flows. Additional information is available on patterns and drivers of the current water-quality
response across the Main Stem in Hydros (2015, 2021a, and 2021c).
Concentrations of some constituents on the Main Stem increase with seasonal spring runoff, including
iron (total and dissolved), aluminum (total), manganese (dissolved and total), suspended solids, and
mercury (total). This pattern reflects the mobilization of these constituents from the watershed and
riverbeds as a result of seasonal snowmelt. Many of these constituents also show elevated
concentrations in the Poudre River after wildfires and flooding. During spring runoff, the influence of
point sources and groundwater recharge are minimized because of the typically high flow volumes
associated with snow melt. While this water-quality pattern is notable in the observed record for many
EXHIBIT A TO RESOLUTION 2025-083
constituents, there are no associated water-quality concerns relative to aquatic life standards that are
driven by this natural phenomenon.
The North Fork is a critical tributary for consideration of potential effects of the Halligan Project on the
Main Stem. While there are no CWA Section 303(d) listings at the mouth of the North Fork or on the
Main Stem below the North Fork for aquatic life standards (except temperature), water entering the
Main Stem from the North Fork tends to have higher concentrations of many constituents as compared
to water in the Main Stem upstream of the North Fork. These include dissolved solids, hardness, arsenic,
and sulfate. Additionally, the North Fork exhibits higher concentrations of ammonia, phosphorus,
nitrogen manganese, and iron on a seasonal basis, corresponding to the timing of stratification and
internal loading from sediments within Seaman Reservoir. These seasonally elevated concentrations on
the North Fork are typically observed from July through September/October, depending on the timing of
turnover in Seaman Reservoir. Currently, the North Fork comprises a seasonally variable fraction of flow
in the Main Stem below its confluence (Figure C-13), with relatively low percent contributions in
summer and early fall (7 percent to 25 percent) and higher percent contributions through the winter
months (30 percent to about 45 percent).
Figure C-13. Average Monthly Percentage of Flow from the North Fork on the Main Stem below the
North Fork Confluence (based on observed flows 2009–2018)
Varying subsurface geology across the Main Stem also plays a role in observed water-quality response.
From upstream to downstream over the focus reach of the Main Stem, the Poudre River passes through
several geologic zones that affect water quality in the river (Figure C-14). The most critical zones are the
Pierre Shale and Fox Hill Sandstone/Laramie Formation. From the lower half of Segment 10b through
Segment 11 and the upper half of Segment 12a (through both Fort Collins and Windsor), the bedrock
below the alluvium is comprised of low-permeability Pierre Shale, which can be a source of selenium to
the river. Farther downstream in the plains (downstream of Windsor in Segment 12a), the bedrock
EXHIBIT A TO RESOLUTION 2025-083
changes to the overlying Fox Hills Sandstone and the Laramie Formations. These sedimentary
formations are less resistant to weathering and are notable sources of dissolved and particulate material
to the river. The effects of these geologic features are apparent in the observed water-quality data,
particularly outside of the snowmelt runoff season.
Figure C-14. Diagram of Geologic Zones of the Poudre River Main Stem Focus Reach
Finally, groundwater recharge and agricultural return flows are important drivers of water quality in the
Main Stem. Groundwater recharge typically comprises the majority of the flow in Segment 12a and
Segment 12b in all months outside of peak snowmelt runoff (Figure C-15). This reflects the stepwise
pattern across Segments 12a and 12b of major diversions reducing flow and groundwater recharge
replacing those flows. Agricultural return flows also make up a notable fraction of flow in the lower
portion of Segment 12a and in Segment 12b in the latter months of the irrigation season (typically
August through October; for example, Figure C-15). This pattern reflects both the increased extent of
shallow alluvium as well as the increased agricultural land use in the Lower Poudre River. Groundwater
recharge sources tend to increase total dissolved solids, nitrate, nitrite, arsenic, iron, and manganese
concentrations in the river. Agricultural return flows tend to increase organic carbon and nutrient
concentrations. The dominance of groundwater recharge and agricultural return flows in these reaches
effectively minimizes the influence of small changes to water quality in Segments 10a, 10b, and 11 on
water quality in Segments 12a and 12b.
EXHIBIT A TO RESOLUTION 2025-083
Figure C-15. Poudre River Fraction of Flow by Source, 2016 Monthly Averages
Source: Hydros 2021
EXHIBIT A TO RESOLUTION 2025-083
Appendix D
Water Quality Sampling Location Maps
EXHIBIT A TO RESOLUTION 2025-083
Appendix D. Water Quality Sampling Location Maps
Figure D-1. Water-Quality Sampling Locations on the North Fork below Halligan Reservoir and its
Tributaries
EXHIBIT A TO RESOLUTION 2025-083
Figure D-2. Macroinvertebrate and Pebble Count Sampling Sites on the North Fork
EXHIBIT A TO RESOLUTION 2025-083
Figure D-3. Water Quality Sampling Locations along the Poudre River
EXHIBIT A TO RESOLUTION 2025-083
Figure D-4. Temperature Gages along the North Fork and Poudre River
EXHIBIT A TO RESOLUTION 2025-083
Appendix E
Parks and Wildlife Commissioner and Public Comment Summary
EXHIBIT A TO RESOLUTION 2025-083
Appendix E. Parks and Wildlife Commissioner and
Public Comment Summary
This appendix summarizes the comments Fort Collins received on the Fish and Wildlife and Mitigation
Enhancement Plan (FWMEP) from the Colorado Parks and Wildlife Commission (Commission) and the
public. This appendix also highlights the changes Fort Collins made to the FWMEP based on the
comments received.
E.1 Commissioner Comments
On May 4, 2023, Fort Collins and C olorado Parks and Wil dlife (CPW) staff presented the proposed
FWMEP to the Commission. Six commissioners provided comments and or asked questions during the
meeting. Commissioner comments provided in the next subsection are not verbatim but a summary of
what was stated. Fort Collins used the meeting recording and transcript to summarize the key points
from each commissioner.
Fort Collins has provided a response to each commissioner’s comments. During the meeting, Fort
Collins responded to some comments, or another commissioner responded to comments. During the
meeting, Fort Collins responded to some comments, or another commissioner responded to
comments. It is no ted within the commissioner comments where the questions were addressed during
the meeting. In addition, some commissioners had overlapping questions/concerns. In those instances,
Fort Collins has referenced the first time the question was addressed.
Commissioner Reading: Would like to see Fort Collins make it permanent that you remove sheep and
goats from your properties and strengthen the language in the document. And to put pressure on your
neighbors, especially The Nature Conversancy, to remove sheep and goats from their property.
Response to Commissioner Reading: Fort Collins has updated Section 5.2.3.1, Prohibition of
Domestic Sheep and Goat Grazing on City Owned Lands Near Halligan Reservoir, to permanently not
graze domestic sheep or goats for weed control or other purposes on any Fort Collins-owned lands
around Halligan Reservoir; enter into a grazing leases that would authorize others to graze domestic
sheep or goats on any Fort Collins-owned lands around Halligan Reservoir; or grant licenses to
convey easements authorizing domestic sheep or goats to graze on any Fort Collins-owned lands
around Halligan Reservoir.
Fort Collins has and will continue to have discussions with adjacent landowners about removing
domestic sheep and goats from their private property. To date, the conversations and negotiations
have been unproductive.
Commissioner Tutchton: The project is providing 8,000 acre-feet of water to fuel future sprawl and the
plan never actually looks at that impact. Instead we focus on the footprint of the project instead of what
the project is going to allow and probably what it took away, which was the agricultural lands that were
providing wildlife habitat.
Provide clarification about the protection of stream flows. It sounded like the flows would be maintained
unless Fort Collins had lawn watering restrictions. Once on, lawn watering restrictions the flows would
EXHIBIT A TO RESOLUTION 2025-083
go away. I think there is room for improvement related to the protection of the summer and winter flows.
Commissioner Tutchton shares Commissioner Reading’s concerns about bighorn sheep. He believes Fort
Collins should get rid of sheep and goat grazing on their properties.
Preble’s meadow jumping mouse (Preble’s) sections completely defers to the US Fish and Wildlife Service
(USFWS). Whatever the USFWS decides will be legally required under their process. Look at including an
enhancement for Preble’s habitat.
Without the fourth water gage we cannot count the potential positive benefits to the river if we do not
know whether or not they exist. The water gage is critical to knowing whether or not there is an actual
benefit in that lowest reach before it hits the main stem.
Has Fort Collins considered on-site solar or small-scale hydro to replace the transmission lines?
Response to Commissioner Tutchton: The purpose and need of the project to provide
approximately 7,900 acre-feet of additional firm yield has been approved as part of the US Army
Corps Engineers (Corps) Environmental Impact Statement (EIS). This is projected to be the buildout of
the Fort Collins Utilities’ water service area, which has been carefully planned for several decades.
Fort Collins has clarified the language around the curtailment of the Winter Release Plan in
Sections 4.2.1.1 and 4.2.1.7. In Section 4.2.1.7, Water Supply Shortage Events and Curtailment
Measures, Fort Collins will consider its future water supply and demand conditions and operations
and the impacts to its water systems. Fort Collins commits to incorporating into its planning and
modeling the potential of operations that include continuing the Summer Low-flow Plan even during
greater water restriction levels. If appropriate and approved by City Council, Fort Collins will
incorporate into future policies that the Summer Low-flow Plan operations continue at some level
even during greater water restriction levels (particularly during restriction levels that allow lawn
watering). Fort Collins will coordinate with CPW on potential changes to these curtailment measures.
Removal of bighorn sheep from Fort Collins property is discussed in the response to Commissioner
Reading.
The USFWS Preble’s Mitigation Plan outlines several enhancement measures. At the request of CPW
staff information related to Preble’s was kept to a minimum in the FWMEP. Fort Collins has added
some additional text to Section 5.1.1.4, Channel Improvements and Modifications of the Calloway
Diversion to reflect that the changes to the Calloway Diversion also enhance Preble’s habitat
connectivity.
Fort Collins and CPW staff have worked together to find a solution related to a fourth gage above
Seaman Reservoir. Fort Collins will perform preconstructi on surveys of the existing flow between the
existing Livermore gage and above Seaman Reservoir in different seasons to determine if there are
flow losses in this lower reach. Details of the preconstruction monitoring and any next steps will be
included in the intergovernmental agreement with CPW. Section 4.2.1.2, Summer Low-flow Plan, has
been updated to reflect this change.
The existing overhead power lines and poles need to be relocated out of the enlarged Halligan
Reservoir inundation zone. Fort Collins is considering other power options. However, alternative
EXHIBIT A TO RESOLUTION 2025-083
power options are currently not part of the Corps EIS. Should Fort Collins choose to pursue an
alternative power source, the Corps will determine if an EIS reevaluation is necessary.
Commissioner May: Concur with other commissioners on the problem with the bighorn sheep
intermingling with domestic sheep and goats. Concerned that if we do not address that issue we’ll
be back here in a few years and hear about the loss of that herd.
Question: Is the current dam under any dam safety compliance order?
Answer given during meeting: Fort Collins responded to this question during the meeting
that the dam has passed inspections every year but will eventually need to be replaced.
Question: Will the current dam be removed or partially removed and inundated?
Answer given during meeting: Fort Collins responded to this question during the meeting that
it has not yet been determined and how it would likely happen if only partially removed.
Question: With the 5 cubic feet per second (cfs), will that be measured at just the diversions or at
Seaman Reservoir? 5 cfs is a very small amount of water. What is the guarantee that the water will
get all the way to the bottom?
Answer given during meeting: Fort Collins responded to this question during the meeting that
the 5 cfs is a commitment to provide that flow at those gages even if more than 5 cfs needs to be
released.
Commissioner May: Believes a stream gage at the very botom of the 22-mile stretch is important to
ensure a minimum flow.
Response to Commissioner May: Removal of bighorn sheep from Fort Collins property is discussed
in the response to Commissioner Reading.
Refer to the response to Commissioner Tutchton regarding the modified proposal to determine if a
fourth gage is necessary.
Commissioner Hasket: Wants to make sure that there is a strong collaborative effort with CPW related
to the continued recreation discussion. Commissioner Haskett is concerned that the recreation
component will be forgotten if it is not in the FWMEP. Commissioner Haskett would like to see it in the
FWMEP.
Response to Commissioner Hasket: Fort Collins and CPW have agreed to continue discussions
related to surface water recreational opportunities, primarily public angling, at the enlarged
Halligan Reservoir in a process separate from the FWMEP processes since the Halligan Project is not
impacting surface water recreation. Section 3.9.3, Evaluation of Future Public Use of the Enlarged
Halligan Reservoir, has been updated to include a commitment in an intergovernmental agreement
with CPW to continue discussion related to surface water recreation at the enlarged Halligan
Reservoir.
Commissioner Adams: Related to Commissioner Hasket’s comment about recreation. Is there a
potential role for one of regional partners to inform and participate around the collective ownership of
this effort?
EXHIBIT A TO RESOLUTION 2025-083
What habitats/wildlife are losing water to supplement the reservoir for this project? Would like to
acknowledge where the water is coming from before it gets to the reservoir and how that is impacting
habitats.
Commissioner May: Answered Commissioner Adams questions during the meeting that he
understands the water rights that Fort Collins is using originally came from agricultural lands that Fort
Collins already converted and grew over and thus not directly impacting existing habitat.
Response to Commissioner Adams: Fort Collins will parti cipate in any recreation discussions but will
defer to CPW staff recommendations on including CPW regional partners to inform and participate in
the discussions.
Commissioner Hauser: I would like to see a firm commitment that holds both sides accountable to
continuing the recreation discussion. Would like to see future updates on both the impact side and the
access side.
Response to Commissioner Hauser: Refer to the response to Commissioner Hasket regarding the
commitment to continuing the recreation discussion.
E.2 Public Comment Received by CPW
During the May 4, 2023 Commission meeting, two groups provided both verbal and writen public
comment on the FWMEP:
•Terry Meyers, Executive Director of the Rocky Mountain Bighorn Sheep Society (RMBS)
•David Nickum, Executive Director of Colorado Trout Unlimited (TU).
In addition to verbal comments, both groups submited writen comments to the Commission, which
were shared with Fort Collins. The writen comments mirror the verbal comments provided by both
groups. Copies of the RMBS and TU leters can be found in FWMEP Appendix F. RMBS and TU’s primary
concerns are listed below followed by a response from Fort Collins.
RMBS Concern: If a water guzzler or stock tank-type water sources are developed for bighorn sheep,
RMBS requests they be designed or placed to exclude domestic ruminants to reduce the potential for
pathogen transmission between domestic ruminants and bighorn sheep.
Fort Collins response to RMBS: Text in Section 4.2.3.18, Bighorn Sheep Habitat Improvements, was
softened to provide flexibility in how habitat improvement monies could be used.
RMBS Concern: Concern that the FWMEP does not provide specific actions that would be taken if
bighorn sheep are documented moving toward or even contacting domestic sheep or goats, or if
respiratory disease is detected in bighorn ship in the Lone Pine Herd.
Fort Collins response to RMBS: CPW has said that if there is confirmed exposure between domestic
sheep and bighorn sheep, the bighorn sheep in question will be euthanized. Text in Section 4.2.3.19,
Bighorn Sheep Collaring Study, has been updated.
RMBS Concern: The RMBS requests that actions be listed that could be implemented if respiratory
disease is detected in Lone Pine bighorn sheep or if contact with domestic sheep and/or goats appears
imminent or is confirmed.
EXHIBIT A TO RESOLUTION 2025-083
Fort Collins response to RMBS: Adaptive management would be used to try and prevent domestic
sheep and bighorn sheep from comingling. Removal of domestic sheep from the area is preferred
but Fort Collins can only remove domestic sheep and goats from their properties. To date atempts
to temporarily or permanently have sheep removed from adjacent properties has been unsuccessful.
However, as discussed in Section 5.2.3.2, Advocate for Cessation of Domestic Sheep and Goat
Grazing on Private Lands Near Halligan Reservoir, Fort Collins will continue to engage with local
landowners to advocate for the both the temporary cessation of domestic sheep and goat grazing
during construction, as well as for the permanent cessation of domestic sheep and goat grazing near
the Halligan Project Area.
As part of the collaring study, CPW will also be performing disease testing at the beginning of each
phase of the collaring study. If CPW identifies a sick bighorn sheep that sheep will be culled from the
herd. CPW has said that if there is confirmed exposure between domestic sheep and bighorn sheep,
the bighorns will be euthanized to prevent disease transmission to other herds. Additional text
related to disease testing has been added to Section 4.2.3.19, Bighorn Sheep Collaring Study.
TU Concern: When modernizing North Poudre diversion structure, incorporate ability to measure
diversion and remove only what is needed, helping to rewater the 2 miles downstream.
Fort Collins response to TU: Once the North Poudre Canal Diversion structure is updated, the winter
and summer releases will be able to pass through the diversion. As discussed in Sections 4.2.1.1 and
4.2.1.2, an existing agreement with North Poudre Irrigation Company (NPIC) prohibits the winter and
summer low-flow releases from being diverted into the North Poudre Canal Diversion.
Fort Collins and NPIC have had discussion about limiting the amount of water being removed at the
North Poudre Canal Diversion to what is necessary since diversion structure will be designed and
rebuilt to allow NPIC to be more selective in the amount of water being diverted. However, NPIC has
indicated they would like to see how the enlarged Halligan Reservoir is operated before they commit
to a new operation approach.
TU Concern: Coordinate with NPIC to ensure effective implementation of flow commitments.
Fort Collins response to TU: As discussed in Section 4.2.1.1, Winter Release Plan, a nd
Section 4.2.1.2, Summer Low-flow Plan, Fort Collins has an existing agreement with NPIC that
prohibits the winter and summer releases being diverted into the North Poudre Canal Diversion. As
discussed in the previous response, the updated structure will have the ability to pass the flows. Fort
Collins will also be installing a gage in and or slightly downstream of the diversion to ensure the
appropriate flows are getting past the North Poudre Canal Diversion as discussed in Section 4.2.1.2,
Summer Low-flow Plan.
TU Concern: Maintain minimum flow releases when drought restrictions are in place for Ft Collins water
customers.
Fort Collins response to TU: Refer to the response to Commissioner Tutchton in Section E.1
Commissioner Comments.
TU Concern: Avoid winter exchanges on the mainstem Poudre that would undermine the benefits of
joint operating program releases intended to maintain overwintering habitat.
EXHIBIT A TO RESOLUTION 2025-083
Fort Collins response to TU: The joint operating program between Fort Collins and the City of Greeley
is a program to release 10 cfs from upper Poudre River basin reservoirs mainly to provide flows in the
upper reaches of the Poudre River where Fort Collins and Greeley’s storage reservoirs are located. Use
of the Halligan enlargement winter exchanges by Fort Collins is critical to meeting its customers’
demands and other water rights obligations. These exchanges would reduce Greeley’s portion of the
joint operation releases of 7 cfs to 4 cfs in the.5-mile stretch between F ort Collins’ pipeline diversion
at Gateway Park to the North Fork confluence.
TU Concern: Focus investment of the $200,000 (per river) for restoration on the North Fork and
mainstem Poudre on sites/projects that will benefit public fisheries.
Fort Collins response to TU: Fort Collins has updated the text in Section 4.3.4, Compensatory
Mitigation for Halligan Project Impact on Stream Temperature, and Section 5.1.1.6, North Fork
Stream Restoration, to reflect Fort Collins and CPW commitment to use the funds within the
Main Stem, or North Fork, within or near the Halligan Project Area, including the North Fork above
Halligan Reservoir and for a restoration project that maximize the overall benefit to the public as well
as the aquatic and riparian ecological function.
TU Concern: Ensure that modifications at the Calloway Diversion do not result in opening up currently
protected riparian habitat to intrusion by livestock.
Fort Collins response to TU: The current design does include a breakaway fence to keep catle out of
Phantom Canyon. The details of the design are not included in the FWMEP since the City does not
have a contract with the landowner to complete the work at this time.
The existing fenced-off riparian area south of the canyon is outside of the footprint of the proposed
Calloway Diversion project and therefore would not be affected by the project.
TU Concern: Increase funding for a recreation lease along the North Fork upstream of Halligan
commensurate with the permanent loss of river fishing due to the proposed inundation.
Fort Collins response to TU: Due to the issues discussed in Section 3.9.1.1, Land Ownership, and
Section 3.9.2, Halligan Project Effect on Recreation and Public Access Fort Collins, is not proposing to
increase the amount of funding for the hunting and fishing lease discussed in Section 4.3.7.2,
Funding of Public Access Lease with Roberts Ranch. However, Fort Collins has agreed to continue
discussions with CPW to have public angling access to the enlarged Halligan Reservoir; refer to
Section 3.9.3, Evaluation of Future Public Use of the Enlarged Halligan Reservoir.
TU Concern: Establish an agreement in principle on how public angling access can be provided for
Halligan Reservoir.
Fort Collins response to TU: Fort Collins has agreed to continue discussions with CPW to have public
angling access at the enlarged Halligan Reservoir; refer to Section 3.9.3, Evaluation of Future Public
Use of the Enlarged Halligan Reservoir.
E.3 Summary of Public Comment Received by Fort Collins
Fort Collins chose to host a virtual open house from May 1 to May 15 for the public to review
information from the FWMEP. A virtual platform was selected because it allows the information to be
accessible longer and can be viewed on a smart phone, tablet, or computer at any time that is
EXHIBIT A TO RESOLUTION 2025-083
convenient for the end user. The virtual public meeting consisted of approximately 40 virtual boards that
provided an overview of the project and highlighted the key mitigations and enhancements of the
FWMEP. The virtual open house also provided links to FWMEP, and the Draft EIS on the Corps website.
Fort Collins advertised the virtual open house through their Halligan Project and Utilities emails list, paid
for boosted posts on the Fort Collins Facebook page, and posted a notice on the Halligan Project website.
The boosted Facebook post received 859 clicks, 52 likes, and 11 comments. The Facebook comments
were not substantive and are not included here.
While the virtual open house was open the Fort Collins virtual open house site received over 894
visitors. Providing public comment was optional for visitors. However, only eight individuals choose to
provide public comments through the Google Form embedded in the virtual platform. The comment
form included two mandatory questions and one optional question. Mandatory questions required a text
response, which could have been as simple as placing an “x” in a box before submitting the form. The
questions on the comment form included:
1)Do you think the mitigation and enhancement measures provided are adequate? Please include
your thoughts.
2)Are there any additional or different mitigation and enhancement measures you would like to see?
3)Do you have other thoughts about the Halligan Water Supply Project? This question was optional for
participants.
A summary of the substantive comments can be found in Sections E.4 through E.6. Commenter quotes
are verbatim. Appendix F contains the full, unedited versions of the public comments.
Fort Collins also required participants to provide a postal zip code, as a way of tracking where the
comments were coming from. All but one zip code was from the Fort Collins or the Livermore Valley
area. Table E-1 shows the location and number of responses per zip code. The one exception was from
Comment ID 2, which provided a zip code of “Puerto Aventuras, Mexico.” The person’s comment
displayed a familiarity with the project area; therefore, the comments were retained.
Table E-1. Location of Halligan Project Virtual Public Meeting Participants
Zip Code Number of Responses
80521 2
80524 1
80525 2
80528 1
Puerto Aventuras, Mexico 1
E.4 Feedback on Question 1
Six of the commenters felt the mitigation measures being proposed in the FWMEP were adequate. Of
the two commenters that felt the FWMEP did not provide adequate mitigation and enhancement
measures only one, Comment ID 8, provides substantive comments. Fort Collins has summarized the
commenters four primary comments below. Appendix F contains the full comment.
EXHIBIT A TO RESOLUTION 2025-083
Comment ID 8: The commenter notes the primary failing of the FWMEP is an “Adaptive Management
EIS.” The commenter also notes “Many of the measures in this plan seem ideally suited for ensuring that
the brown trout population thrives in the North Fork. Brown trout may be the single most important
factor driving down native fish populations.” Related to brown trout management, the FWMEP provides
“litle indicati on of how temperature release might be used to manage to support native fish
management” through releases from the multilevel outlet works (MLOW). Adaptive management is
needed for ramping rates, mitigation measures intended to enhance riparian habitat, and restore stream
habitat. What does "Adaptive management in response to environmental monitoring is indirectly
incorporated into some mitigation and enhancement measures…even mean in this context, especially for
MLOW and temporary environmental pool?” Lastly, “As the plan currently stands, there is litle in terms of
objectives beyond a hope/expectation that native fish and these other ecosystem components will
benefit. There is also no clear process for adapting over time; quite the opposite--many of the planned
actions are so ‘locked in’ that they could not be adjusted even if there was evidence that they were not
working.”
Response to Comment ID 8: Many of the mitigations proposed in this plan also have a regulatory
mechanism that defines their success. As permits have not yet been obtained, the specific of the
success criteria cannot be provided. In addition, if a mitigation is failing within the context of a
regulatory permit, the process must be adapted within the regulating agency framework. For items
where there is not a regulatory framework, such as with the bighorn sheep collaring study, Fort
Collins and CPW will continue to discuss the logistics, which will include some form of adaptive
management, related to this effort through the development of the intergovernmental agreement.
The term indirectly as it relates to the MLOW is outlined in Section 4.2.2.1, Multilevel Outlet
Structure, which states “an MLOW is not expected to be necessary from the perspective of aquatic
life mitigation efforts… [and is therefore] not a commitment in the FWMEP.” For the temporary
environmental pool, Fort Collins a nd CPW have not agreed to specific management objects beyond
what is stated in Section 5.1.1.1, Temporary Environmental Poll.
E.5 Feedback on Question 2
Three of the eight commenters indicated the measures provided are reasonable. One commenter
recommended the dam be removed. Comment ID 2 and Comment ID 3 are more general comments that
Fort Collins has responded to below. Comment ID 6 and Comment ID 8 provided substantive comments.
Comment ID 8 succinctly reiterated the comment theme from Question 1, which was addressed
previously; therefore, Fort Collins is not providing a response here, refer to the response provided in
Section E.4. Comment ID 6 provided four additional measures for consideration. Fort Collins has
summarized all the comments and provided responses. Appendix F contains the full comments.
Comment ID 2: Would like to see “Continued and improved per capita water use in Fort Collins.”
Response to Comment ID 2: Fort Collins has a strong commitment to water conservation and
continues to innovate, providing ongoing and relevant water efficiency support to the community.
EXHIBIT A TO RESOLUTION 2025-083
The 2022 Water Conservation Annual Report,1 indicates that community gallon per capita per day is
down 34% since 2000; 173.3 million gallons of treated water was saved in 2022 (Fort Collins 2022).
Comment ID 3: “Curious if the greenback trout still exist and if they are part of the consideration?”
Response to Comment ID 3: Greenback cuthroat trout (Oncorhynchus clarkii stomias) reclamation
and reintroduction were considered for the North Fork, but restoration of greenback cuthroat trout
in Fish Creek and Dale Creek was part of that potential restoration plan. Refer to FWMEP
Section 4.1.2, Changes from the Draft EIS Conceptual Mitigation Plan, for more information on why
the concept of greenback cuthroat trout population restoration was ultimately dismissed.
Comment ID 6: Commenter indicated there is a bald eagle and golden eagle nests near the dam and
North Poudre Canal Diversion structure that could be impacted by construction. The impact to the
nesting and territory occupation needs more assessment and in particular avoidance of construction
activities prior to and during nesting. The increased flows of 3 and 5 cfs will help but still does not
approach the range of historical flows. “I encourage talking to CWCB to explore if their instream flow can
be used to enhance flows between Halligan and Seaman reservoirs.” The proposed ramping rates are too
short. Lastly, “The conservation easement on the Roberts Ranch does not allow for public recreational
access. Therefore the proposed lease for public hunting and fishing on the Krause Field would be a
violation of the easement. The Nature Conservancy (TNC) should be consulted before any steps are
taken on this proposal.”
Response to Comment ID 6: As outlined in Section 4.2.3.4, Migratory Bird and Raptor Surveys, Fort
Collins will be doing migratory bird and raptor monitoring every other year before construction to
collect baseline data. Prior to construction, surveys will be done to determine if there are any active
nests in the construction area. If nests are identified, Fort Collins will consult with CPW to determine
which measures from their buffer guidelines for nesting raptors would minimize any potential
adverse impacts from construction related activities.
As described in Section 4.3.8, Instream Water Rights, Fort Collins is commited to protecting the
project’s mitigations releases for approximately 22 miles downstream using the Protected Mitigation
Release statute (Colorado Revised Statutes Section 37-92-102[8]). Any additional future instream
flows provided by Colorado Water Conservation Board (CWCB) could be accommodated in the
Halligan Dam operations; however, Fort Collins is not aware of any such current or future CWCB-
protected instream flows.
The ramping rates proposed by Fort Collins and included in Section 4.2.1.5 Ramping Rate Limitations
of the FWMEP, have been developed by hydrologists, ecologists and geomorphologists to determine
the optimal rates to provide timing, frequency, magnitude and duration of flow to mimic a nature
flood cycle as best as possible given the constraints of the available water supply.
CPW has led the effort to obtain a hunting and fishing lease for Krause Field of the Roberts Ranch
Conservation Easement. Fort Collins is only providing funds to support an already existing hunting
and fishing agreement.
1 htps://www.fcgov.com/utilities/img/site_specific/uploads/23-25044-2022-water-
conservation-reportfinal.pdf?1685659564
EXHIBIT A TO RESOLUTION 2025-083
E.6 Feedback on Question 3
Fort Collins received seven comments on this optional question. Five of the seven comments provided a
positive response to the project. One comment is a question related to future recreation. Two comments
express disappointment with the project. As the question is optional Fort Collins is not providing a
response to all the comments.
Comment ID 3: “Too early for access planning for fishing?”
Response to Comment ID 3: Fort Collins and CPW have agreed to continue discussions related to
recreational opportunities at Halligan Reservoir in a process separate from the current processes to
enlarge Halligan Reservoir and the FWMEP. Refer to Section 3.9.3, Evaluation of Future Public Use of
the Enlarge Halligan Reservoir.
EXHIBIT A TO RESOLUTION 2025-083
Appendix F
FWMEP Virtual Open House Public Comments
EXHIBIT A TO RESOLUTION 2025-083
P.O. Box 349 • Clifton, CO • 81520-0349
May 4, 2023
Colorado Parks and Wildlife Commissioners
C/O Colorado Parks and Wildlife
6060 Broadway
Denver, CO 80216
RE: Halligan Water Supply Project Fish and Wildlife Mitigation and Enhancement Plan
Dear Commissioners:
Please accept the following comments on the Halligan Water Supply Project Fish and Wildlife Mitigation
and Enhancement Plan (mitigation plan) on behalf of the Rocky Mountain Bighorn Society (RMBS). The
RMBS is 501(c) (3) organization with a mission to promote the science-based management of the
bighorn sheep, educate the public about their life and habitat, and assure the sportsman’s rights in
proper opportunities.
The RMBS appreciates the thoroughness of City of Fort Collins and Colorado Parks and Wildlife staff in
recognizing potential impacts the Halligan Water Supply Project may have on the Lone Pine and other
nearby bighorn sheep herds, and the willingness of the City to mitigate those impacts. In addition, we
request a few improvements and clarifications be added to the mitigation plan.
Habitat Enhancement
The RMBS supports efforts to address invasive cheatgrass in order to improve bighorn sheep foraging
opportunities. However, we question the need for additional water sources given that bighorn sheep are
well adapted to dry western landscapes. There are several creeks and springs in the vicinity (Rabbit,
Lone Pine, North Fork of the Poudre, etc.). Moreover, stock tanks have been observed to bring bighorn
sheep in close contact with domestic ruminants which has resulted in suspected pathogen transmission
in some circumstances which may result in respiratory disease in wild sheep. If guzzler or stock tank type
water sources are developed for bighorn sheep, we request that they be designed or placed to exclude
domestic ruminants in order to reduce the potential for pathogen transmission between domestic
ruminants and bighorn sheep.
Construction Activity Mitigation
The RMBS is pleased to see that dust mitigation will be implemented during construction activities, as
dust is a respiratory irritant that may increase bighorn sheep susceptibility to respiratory diseases
including pneumonia. We also appreciate the willingness of the City of Fort Collins to compensate for
any bighorn mortalities during construction and for a two year period post-construction.
EXHIBIT A TO RESOLUTION 2025-083
We recognize the thorough discussion of potential displacement of bighorn sheep that may result in
contact with nearby domestic sheep and/or goats on private lands. The commitment to monitoring
bighorn sheep movements using GPS collar technology prior to, during, and post construction is
welcome and necessary. However, we do not see specific actions that would be taken if bighorn sheep
are documented moving toward or even contacting domestic sheep or goats, or if respiratory disease is
detected in bighorn within the Lone Pine Herd.
As acknowledged in the mitigation plan, in the event of respiratory disease in the Lone Pine herd,
dispersing bighorn sheep – especially rams traveling during the breeding season – may expose bighorn
sheep in the Lower Poudre herd. In addition, if the Lower Poudre herd sustains a respiratory disease
event, it is predictable that seasonal ram movements will spread pathogens to the Upper Poudre
bighorn herd and on to the Rawah bighorn herd and possibly to the Never Summer bighorn herd as well.
The RMBS requests that actions be listed that could be implemented if respiratory disease is detected in
Lone Pine bighorn sheep or if contact with domestic sheep and/or goats appears imminent or is
confirmed. In an effort to prevent or contain a respiratory disease outbreak, the RMBS would support
removal, including by lethal means, of bighorn sheep that have contacted domestic sheep or goats or
bighorn sheep that exhibit respiratory disease causing pneumonia.
Thank you for the opportunity to comment on the Halligan Water Supply Project Fish and Wildlife
Mitigation and Enhancement Plan. Please do not hesitate to reach out to me if you have questions or if
the RMBS can be of assistance in any way.
Respectfully,
Terry E. Meyers
Executive Director
Attachment:
Lone Pine Herd (S40) History and Status
The Lone Pine bighorn sheep herd is the result of a 1977 transplant of 19 bighorn from Trickle Mountain
(Vieira 2012). After the initial release, the herd grew rapidly, but by 1988 there were only an estimated
20 bighorn remaining (Bailey 1990, Vieira 2012). Since then, estimates have ranged from years with no
observed bighorn up to about 35 bighorn (Vieira 2012). There is no historical documentation of native
bighorn in the Lone Pine area or even in the Poudre Canyon (S1 and S58), although bighorn have long
been documented in the Rawah Range (S18) (Vieira 2012). The 2012 Poudre-Rawah-Lone Pine Herd
Management Plan (Vieira 2012) describes documented movement between the Upper Poudre (S1) and
the Rawah Range (S18), and suspected movements between Lone Pine (S40) and Lower Poudre (S58).
There is no reason to doubt there is some interaction, especially by rams, between the Upper Poudre
(S1) and Lower Poudre (S58) bighorn herds given the continuous canyon habitat.
EXHIBIT A TO RESOLUTION 2025-083
There is considerable potential for bighorn to contact domestic ruminants in the Lone Pine area. A large
band of domestic sheep graze one private parcel in spring to reduce larkspur before cattle are grazed
later in the summer. Domestic goat flocks occur on private land. Bighorn sheep have been seen in
proximity to cattle on private land. Cattle graze on Cherokee State Wildlife Area.
Literature Cited:
Bailey, J. A. 1990. Management of Rocky Mountain Bighorn Sheep Herds in Colorado. Colorado Division
of Wildlife Special Report Number 66. 24 pages.
Vieira, M. 2012. Bighorn Sheep Management Plan: Data Analysis Unit RBS-1 Poudre/Rawah/Lone Pine.
Colorado Parks and Wildlife.
https://cpw.state.co.us/thingstodo/Pages/HerdManagementPlans.aspx
EXHIBIT A TO RESOLUTION 2025-083
Trout Unlimited: America’s Leading Coldwater Fisheries Conservation Organization
Colorado Office: 1536 Wynkoop Street, Suite 320, Denver, CO 80202
PHONE: (303) 440-2937 WEB: www.coloradotu.org EMAIL: david.nickum@tu.org
May 17, 2023
To: Colorado Parks and Wildlife Commission
Re: Halligan Water Supply Project Draft Fish and Wildlife Mitigation and Enhancement Plan
Colorado Trout Unlimited and the Rocky Mountain Flycasters Chapter (collectively “TU”) appreciate
the opportunity to provide these written comments on the Draft Fish and Wildlife Mitigation and
Enhancement Plan for the Halligan Water Supply project (Plan). TU represents more than 11,000
members across Colorado including nearly 1,200 in the Rocky Mountain Flycasters Chapter serving
Fort Collins/Loveland and the surrounding areas. TU has been extensively involved in conservation
efforts throughout the Cache la Poudre basin, including work by the local chapter on the Eagle’s Nest
Open Space located along the North Fork of the Poudre downstream of the project.
TU appreciates the work that Colorado Parks and Wildlife (CPW) staff have done with the City of Fort
Collins in developing this plan to date and are supportive of many elements in the plan. We do see
some specific areas in need of further refinement, as outlined in our comments below, and look
forward to working with CPW and the City to address these concerns. In summary, our recommended
adjustments within the plan are:
When modernizing North Poudre diversion structure, incorporate ability to measure diversion
and remove only what is needed, helping to rewater the 2 miles downstream.
Coordinate with North Poudre Irrigation Company to ensure effective implementation of flow
commitments.
Maintain minimum flow releases when drought restrictions are in place for Ft Collins water
customers.
Avoid winter exchanges on the mainstem Poudre that would undermine the benefits of joint
operating program releases intended to maintain overwintering habitat.
Focus investment of the $200,000 (per river) for restoration on the North Fork and mainstem
Poudre on sites/projects that will benefit public fisheries.
Ensure that modifications at the Calloway diversion do not result in opening up currently
protected riparian habitat to intrusion by livestock.
Increase funding for a recreation lease along the North Fork upstream of Halligan
commensurate with the permanent loss of river fishing due to the proposed inundation.
Establish an agreement in principle on how public angling access can be provided for Halligan
Reservoir.
These recommendations are described further in our more detailed comments below.
Flow measures – North Fork. Base flows are the most critically limiting flow factor on the North
Fork between Halligan and Seaman Reservoirs, with periods of zero or near-zero flows hampering the
ability of trout and native fish species to survive and thrive in the river. Accordingly, we are
appreciative that the Plan addresses this problem by incorporating minimum flow commitments of 3
cfs (winter) and 5 cfs (summer). While these flows are less than a healthy minimum instream flow that
Colorado Trout Unlimited
Rocky Mountain Flycasters Chapter
of Trout Unlimited
EXHIBIT A TO RESOLUTION 2025-083
would be recommended for a stream of the North Fork’s size, a consistent base flow will represent
meaningful improvement from the status quo by eliminating zero flow days and helping to sustain and
refresh pools with holding habitat for fish.
TU applauds the City for its inclusion of a flushing flow program to bypass the projected three highest
flow days each year, along with ramping on the days prior to and following that three-day period. This
should help with some key ecological functions including flushing of sediment and providing riparian
vegetation with some spring saturation. We are especially impressed that the outlet has been designed
to accommodate release of these important peak flows up to 800 cfs; we anticipate that in most years
with peaks that would exceed that level, Halligan will fill and be spilling so as to provide a peak
flushing flow.
Similarly, we support the proposed ramping rates on releases to avoid impacts that more sudden flow
changes might otherwise create for fish downstream. In particular, we support gradual down-ramping
of flows when releases are being dropped so as to reduce the likelihood of fish becoming stranded in
habitats that will then be dewatered as flows continue to drop.
The City’s proposal to modify the existing North Poudre Irrigation Company diversion will facilitate
these flow programs, enabling controlled flow releases of the proposed 3 and 5 cfs minimums as well
as providing for fish passage at the diversion which currently serves as a barrier to fish movement.
This diversion has traditionally swept the river, with water run through a tunnel to a point at which
flows are measured and directed into the conveyance to NPIC users while excess flow is returned
through an overflow channel to the North Fork approximately two miles downstream from the
diversion. The City’s proposal will help return minimum flows to that impacted reach. We
recommend also exploring options for measuring diversions at the NPIC diversion structure
itself, so that water in excess of delivery needs is kept in the stream throughout rather than
removed for a two mile stretch of habitat. This could create further ecological lift and connectivity
on the North Fork without impairing delivery of NPIC’s water rights into their system.
On all of the proposed flow measures, ensuring the anticipated benefits will depend upon effectively
engaging NPIC as well given their involvement in operations of the historic pool portion of the
enlarged Halligan. The benefits of the flushing flow and ramping programs in particular will depend
upon such collaboration, or the benefits will be reduced or negated (especially downstream of the
NPIC diversion). We are hopeful that the City’s status as a major shareholder in NPIC will give them
sufficient influence to ensure such coordination across the full range of flow management efforts
included in this Plan. The success of this Plan is dependent upon the diligent compliance by all
relevant parties, without exception.
Finally, we are concerned that the City proposes that its flow commitments could be discontinued
during times when they are in first-stage drought restrictions – meaning that outdoor watering would
be limited to two days per week. That is a very modest level of drought restriction, more aligned with
what should be the norm for landscape irrigation during normal conditions, and we are concerned that
this loophole will significantly diminish the benefits being claimed under the Plan. Given the large
volumes of water associated with the peak flow bypass program, we can understand the need to forego
those commitments when in drought periods. However, we suggest that the minimum release
commitments should be maintained regardless of drought restriction status, or that an
exemption from those commitments be tied to more significant restrictions (such as a ban on
EXHIBIT A TO RESOLUTION 2025-083
outdoor watering). Given the low volumes involved with the base flow program, we would anticipate
the City’s water demands even under low or moderate drought restrictions would be sufficient to use
the base flow releases in meeting municipal needs.
Flow measures – mainstem Poudre. While the greatest flow impacts of the Halligan project take
place on the North Fork, the mainstem Poudre will also be impacted on the exchange reach when water
sent down the North Fork is exchanged up for diversion at the City’s upstream points of diversion. Key
low-flow challenges for the Poudre’s fishery include elevated summer temperatures and limited
overwintering habitat. To address the former, the Plan includes an agreement not to exchange up the
mainstream during key summer periods. However, no similar consideration is given to winter low-flow
impacts.
To address the concern of low winter flows throughout the mainstem Poudre, a joint operating program
has been in place for many years involving Fort Collins, Greeley, and the Water Supply and Storage
Company, each of which have significant reservoir facilities in the headwaters. Through this program,
releases are made to maintain 10 cfs so as to support appropriate overwintering habitat for the resident
fishery. TU would ask that the Plan add provisions to avoid exchanging up the mainstem against
those base winter releases under the joint operating program, thereby reducing that program’s
benefits to winter habitat.
Other fishery mitigation. The Plan includes provisions for mitigation and enhancement through
investment in two projects of $200,000 each toward habitat connectivity and/or restoration on both the
North Fork and the mainstem Poudre. We applaud this commitment, and TU hopes to work in concert
with CPW and the City in order to leverage these dollars further so as to increase the ultimate benefits
to stream habitat and fisheries. We recommend that the Plan note a priority for use of these funds
in locations that will benefit publicly-accessible fisheries. TU would welcome the opportunity to
partner with the City and CPW on these projects, drawing from its extensive volunteer base to expand
the impact of these investments.
TU applauds inclusion in the Plan of adjustments to multiple diversion structures so as to restore fish
passage and improve habitat connectivity within the watershed. Providing free up- and down- stream
movement for fisheries and other aquatic life contributes to the health of the watershed and increases
resiliency of aquatic species in the face of localized disturbances. We are pleased to see reconnection
of habitat at the North Poudre, Calloway, and mainstem Fort Collins diversions included. In the case
of Calloway, we note that the existing diversion blocks cattle intrusion into currently protected
upstream riparian habitats. We recommend that modifications at the Calloway diversion are
installed such that they do not open up that protected riparian corridor to intrusion by livestock.
Long-time members of TU in the region recall the disastrous sediment releases in 1996 that smothered
habitat and killed fish in the Phantom Canyon reach downstream of Halligan. We therefore appreciate
the City’s statement in the Plan that they will manage future sediment releases to occur in conjunction
with spilling of high flows, to provide for sufficient flows to transport any released sediment through
the downstream reaches.
The Plan acknowledges the need to further examine and address water quality in the context of 401
certification for the Halligan project. We note that the Rocky Mountain Flycasters Chapter TU is
collaborating with The Nature Conservancy this year to install a new water quality monitoring station
EXHIBIT A TO RESOLUTION 2025-083
in Phantom Canyon. We are hopeful that real-time data from that station can assist CPW and the City
in assessing baseline and future conditions so as to ensure that any adverse impacts to water quality
can be recognized and addressed.
Recreation. For years, anglers have enjoyed access on the North Fork above Halligan Reservoir
through the Cherokee State Wildlife Area (SWA). With existing access along approximately ¾ of a
mile lost to inundation under the Halligan project, we were pleased to see the Plan include provisions
for the City to help fund continued leasing of approximately a mile of water on the north side of the
North Fork, complementing the existing access on the south bank and helping to reduce potential for
inadvertent trespass or other use conflicts that might adversely effect fishing opportunity. However, the
proposed funding level toward an access lease ($135,000) is intended to cover 30 years at the existing
lease cost. As the loss of access to inundation is permanent, the mitigation provided should be
perpetual as well. We recommend that the Plan be modified to provide a level of funding
consistent with the market value of a permanent access easement for the reach; if a perpetual
agreement cannot be secured with the landowner, the funds should then be applied to other public
access in the basin that may be identified by CPW staff.
The Plan does not ultimately address the question of providing angling access to the enlarged Halligan
Reservoir itself, instead deferring that matter to future discussions. We recognize that specific details
must be addressed on how such access would be managed in a sustainable manner and avoid adverse
impacts on wildlife in the Cherokee SWA, for example by the continuation of existing closures to
protect wintering areas utilized by deer and elk. However, rather than deferring the question of access
entirely to the future – with no certainty that it will ultimately be addressed – CPW and the City should
at least define a process by which access will be provided. TU recommends that the Plan include an
agreement in principle to opening Halligan Reservoir to angling access, with recognition of the
stewardship needs for the City and CPW that will provide sideboards on how such access is
managed. Full details can then be resolved between CPW and the City in a manner consistent with
those guiding principles. We fear that without such an agreement, the potential public benefit of this
$157M investment via access to an excellent, nearby recreation destination will never be realized.
We appreciate the opportunity to comment, and look forward to working with the Commission, CPW
staff and the City to address these issues and refine the Plan in a manner that we hope can enjoy broad
public support.
EXHIBIT A TO RESOLUTION 2025-083
ID Timestamp 1. Do you think the mitigation and enhancement measures provided are adequate? Please include
your thoughts.
2. Are there any additional or different mitigation and
enhancement measures you would like to see?
3. Do you have other thoughts about the Halligan Water
Supply Project?
Zip code of
residence.
1 5/2/2023
9:02:40
Yes, they sound like more than enough. If our biggest concerns are bighorn sheep, which the world
isn't running out of anytime soon, and a rare mouse, which no one even knows about, we're in great
shape. It's my understanding that there's debate about whether the mouse can even be classified as
its own species. In any case, if they can't survive the enlargement of one small reservoir, there was no
saving them to begin with. I'm glad we're keeping them in mind, but the animals will be fine. Most
will be better off it seems. Let's not lose the forest for the trees.
No, I do not think we need to add to our 170 pages of
mitigation and enhancement measures.
Let's get this show on the road! Couldn't be clearer that
this is a net gain for 95% of all stakeholders, including fish
and wildlife.
80528
2 5/8/2023
16:41:52
Yes Continued and improved per capita water use reductions in
Fort Collins.
Intentionally left blank. 80524
3 5/10/2023
17:03:15
Yes, appears to be the best idea with good planning I have not read the entire brochure, but I will ask my
question and see what response comes back. I know from
fishing in the streams above Halligan in my youth that there
is/was a population of greenback trout in Fish Creek,
maybe Dale Creek. Curios to know if they still exist and if so
are they part of the consideration? I managed a water
treatment project for the University of Colorado at the
Mountain Research Center and had the duty to protect the
breeding population of Como Creek Greenback Trout, mid
90s, so I know the trout preservation process and
watershed protection process is intense.
Too early for access planning for fishing? I used to hike into
the streams feeding Halligan and N Fork via Turkey Roost.
Once in a while would get a permit from Karl to fish
Phantom Canyon until Game and Fish flushed the dam and
filled the canyon with debris:)
Puerto
Aventuras,
Mexico
4 5/11/2023
8:10:11
No. Halligan Dam needs to be torn down. Halligan Dam needs to be torn down. The City must focus on water conservation and tear down
Halligan Dam.
80521
5 5/11/2023
21:10:58
Yes - thanks for all the work that went into addressing all the issues I cannot think of any. An excellent idea. Extremely low impact compared to
building a new dam in a different location on the steam.
Replaces a very old dam hopefully before it would fail.
Updating infrastructure that is this old is always a good
idea.
80525
EXHIBIT A TO RESOLUTION 2025-083
ID Timestamp 1. Do you think the mitigation and enhancement measures provided are adequate? Please include
your thoughts.
2. Are there any additional or different mitigation and
enhancement measures you would like to see?
3. Do you have other thoughts about the Halligan Water
Supply Project?
Zip code of
residence.
6 5/12/2023
16:22:58
I support the following mitigation and enhancements measures:
Flows to reduce 0-water flow days.
Ramping up and down of flows and peak flow releases.
Increasing winter flows and summer flows.
The focus on aquatic native macroinvertebrates and small bodied native fish and rainbow trout.
Radio collaring and tracking of big horn sheep to determine movements to ensure increased
survival.
Fish passage projects and restoration of the stream segment upstream and downstream of the
Calloway diversion.
No public access on Halligan Reservoir.
Maintenance and improvement of PMJM habitat.
Managing construction activities to reduce impacts to wildlife and reduce expansion of non-native
weeds.
Redesign of the canyon diversion for the NPIC canal.
Additional monitoring stations.
Yes. I suggest the following.
A bald eagle nest is located 1/2 mile downstream in The
Nature Conservancy Preserve. The river and reservoir is
also used year round by bald eagles. I do not agree that
impacts will be negligible. Construction may cause the
bald eagle nest site to be abandoned and may also
interfere with foraging and territory occupation. This
needs more assessment and in particular avoidance of
construction activities prior to and during nesting.
Golden eagles nest upstream and downstream of the
NPIC canyon diversion. Reconstruction of the diversion
may impact golden eagle nesting and territory
occupation. This needs more assessment and in
particular avoidance of construction activities prior to
and during nesting.
3cfs winter flow is a very low and minimal flow offer.
This flow barely connects pools and barely helps
maintain dissolved oxygen levels. Any increase in winter
flows would provide higher survival rates for fish and
aquatic insects.
5cfs during the summer months will help, but still does
not approach the range of historic flows. I encourage
talking with CWCB to explore if their instream flow can
be used to enhance flows between Halligan and Seaman
reservoirs.
Ramping rates used in the past were most effective
when delivered over a 3-day period. This occurred via
the agreement between TNC and NPIC. 18 hours and 10
hours proposed are too short.
The conservation easement on the Roberts Ranch does
not allow for public recreational access. Therefore the
proposed lease for public hunting and fishing on the
Krause Field would be a violation of the easement. The
Nature Conservancy should be consulted before any
steps are taken on this proposal.
I support the City of Fort Collins being the sole operator of
a permitted new Halligan Reservoir. This will ensure all
parts of the mitigation and enhancement plan are carried
out as permitted.
80536
7 5/15/2023
11:01:11
Yes. An extensive amount of analyses has been performed and it seems apparent that the
environmental conditions along the North Fork of the Poudre and in other areas will be improved
with the construction of the Halligan Reservoir Supply Project.
The measures provided are extensive and reasonable as
presented and I do not believe additional measures are
necessary.
The project as presented should provide increased
reliability for the City of Fort Collins water supply system
with important mitigation and enhancement measures to
protect and improve the local fishery and wildlife
resources.
80525
EXHIBIT A TO RESOLUTION 2025-083
ID Timestamp 1. Do you think the mitigation and enhancement measures provided are adequate? Please include
your thoughts.
2. Are there any additional or different mitigation and
enhancement measures you would like to see?
3. Do you have other thoughts about the Halligan Water
Supply Project?
Zip code of
residence.
8 5/15/2023
19:53:17
The planned measures are good but not adequate for the aquatic and streamside ecosystems. They
are inadequate because there is no assurance that the goals for these ecosystems will be achieved,
and there is no comprehensive adaptive management plan set up for learning and adjusting over
time. This is most obvious with the goals for small-bodied native fish, where notably:
BIGGEST ISSUE FOR WHICH ADAPTIVE MANAGEMENT EIS NEEDED: Many of the measures in this plan
seem ideally suited for ensuring that the brown trout population thrives in the North Fork. Brown
trout may be the single most important factor driving down native fish populations. Ensuring 3 cfs in
winter and 5 cfs ensures that there will always be sufficiently cool temperatures and sufficient oxygen
for brown trout to thrive. Creating connectivity across the current stream flow diversion structures
will allow the brown trout to roam at will; currently it is difficult for the brown trout to live
downstream of the NPIC structure, and any large browns that get caught below the structure cannot
travel back upstream. There is good reason to think that flow and diversion mitigation will make the
already strong brown trout population even stronger, and that this stronger population will have
even greater negative impact on the native fish.
The FWMEP says "Spawning of small-bodied native fish in the North Fork is temporally limited by
seasonal water temperatures. Species observed in the North Fork below Halligan Reservoir require
temperatures that range from 12 degrees Celsius (°C) to 29°C (Woodling 1985). Based on
temperature data analyzed from 2016 to 2020 (Hydros 2021d), the North Fork below Halligan
Reservoir currently maintains suitable spawning temperatures for small-bodied native fish from
approximately June to October." BUT, current temperatures below Halligan come nowhere close to
29 deg C, which per the above statement is "REQUIRED." It's actually probably not required that high,
but there is good evidence that the native populations would benefit from higher temperatures that
make trout uncomfortable. And in any case "current" isn't what matters; how the multi-level outlet
works will be managed is what matters, but there is little indication of how temperature of releases
might be managed to support native fish. (part of the issue here is that there is a commitment to
"aquatic life standards", which is a problem here because of the transition-zone status of this stream-
-what will be done to managing the conflict needs of the fish in this zone?)
Ramping rates are based on rough understanding of the ecosystem, and the 3-day duration is also a
guess. You don't know how this is going to play out actually. Adaptive management is needed.
Other mitigation measures intended to enhance riparian habitat for Prebles, restore stream habitat,
and restore/maintain riparian habitat generally are similarly problematic in the absence of adaptive
management.
The plan says, "Adaptive management in response to environmental monitoring is indirectly
incorporated into some mitigation and enhancement measures in the FWMEP, including the MLOW,
bighorn sheep collaring and mortality compensation, sediment management, and temporary
environmental pool measures." What does "indirectly" even mean in this context, especially for
MLOW and TEP? Adaptive begins with setting objectives, monitoring and learning over time, and
adjusting in response to learning. As the plan currently stands, there is little in terms of objectives
beyond a hope/expectation that native fish and these other ecosystem components will benefit.
There is also no clear process for adapting over time; quite the opposite--many of the planned actions
are so "locked in" that they could not be adjusted even if there was evidence that they were not
working.
Please require a clear, robust, outcomes-based adaptive
management plan. Also, include experts and stakeholders
outside Fort Collins and CPW.
Overall, I prefer this project to Fort Collins joining NISP.
That said, there is a huge missed opportunity to do right by
the river, and to be an example for all of Colorado and the
West.
As a Fort Collins resident, I expect the City to go above and
beyond in taking care of all the other species and
ecosystems that co-reside with us in and along the Poudre
River.
80521
EXHIBIT A TO RESOLUTION 2025-083
Exhibit B
WATER DEDICATION AND DELIVERY AGREEMENT
EXHIBIT A TO RESOLUTION 2025-083