HomeMy WebLinkAboutCOUNCIL - AGENDA ITEM - 12/11/2007 - NORTHERN INTEGRATED SUPPLY PROJECT DATE: December 11, 2007 WORK SESSION ITEM
STAFF: John Stokes FORT COLLINS CITY COUNCIL
SUBJECT FOR DISCUSSION
Northern Integrated Supply Project.
GENERAL DIRECTION SOUGHT AND SPECIFIC QUESTIONS TO BE ANSWERED
Staff is preparing for the release of a Draft Environmental Impact Statement DEIS associated with
P ep g P (DEIS)
the Northern Integrated Supply Project (NISP). Staff plans to develop comments on the DEIS for
Council's consideration around the time of the expected release of the DEIS in early 2008. Staff is
seeking Council reactions and guidance related to staff s current efforts to analyze NISP.
BACKGROUND
The Northern Colorado Water Conservancy District(the"District")is proposing a water storage and
supply project known as the Northern Integrated Supply Project (NISP). The District made a
presentation about the project to City Council on May 22, 2007. Based on that presentation, City
Council directed staff to be prepared to submit comments to the Army Corps of Engineers (the
"Corps") when the Corps releases the DEIS.
The staff presentation for this work session consists of four elements:
1. An overview of historic Poudre River flows and operations;
2. An operational overview of NISP;
3. A brief overview of staff work related to NISP; and,
4. A brief review of the potential impacts of NISP to the Poudre River through town.
Staff s presentation for this work session is intended to provide background and context about NISP
in order to assist Council in gaining a general understanding of some of the major issues. Staffwill
return to Council sometime in early 2008 for a more detailed examination of the issues.
NISP is a project designed by the District and fifteen municipalities and water districts. The Project
is intended to increase water supplies for the collaborating entities. Several different alternatives to
provide enhanced water supplies have been proposed by the District and its partners. The preferred
alternative identified by the partners involves the construction of a new reservoir to the northwest
of Fort Collins(the"Glade"reservoir)and development of what is known as the South Platte Water
Conservation Project. The preferred alternative(as well as three additional alternatives)is currently
under analysis by the Corps, and a draft DEIS is schedule to be released sometime in early 2008.
The DEIS is a detailed, federally required review of the alternatives and will include extensive
analysis of environmental impacts associated with the alternatives.
December 11, 2007 Page 2
City staff from Utilities and the Natural Resources Department have been preparing for the release
of the DEIS. Staffs work primarily is focused on the potential impacts of NISP's preferred
alternative to an approximately ten-mile reach of the Poudre River from Overland Trail road to I-25.
In order for Council and the public to gain a better understanding of the potential impacts of NISP,
staff will provide a videotaped presentation that will be available on Channel 14 prior to December
I 1 th. The presentation will include an overview of historic Poudre River flows and operations and
of how the NISP preferred alternative will work. Key points from this portion of the presentation
are provided as Attachment 1.
SUMMARY OF STAFF WORK IN ADVANCE OF THE DEIS RELEASE
Poudre Technical Advisory Group:
On November 1 st, the Natural Resources Department (NRD) and Utilities' staff hosted a 4-hour
roundtable discussion with technical experts to assess past, present and potential future condition
of the Poudre River. A technical summary("white paper")will be prepared to present an overview
of major findings and issues,potential change to river dynamics and future conditions. Staff hopes
to have this summary available to Council prior to the release of the DEIS.
Evaluation of Hydrologic Modeling and Potential Impacts—Ayres Associates
Ayres Associates has been contracted by the NRD and Utilities to make a broad assessment of the
potential impacts of Glade Reservoir on the Poudre River between Overland Trail and I-25. Phase
I of a possible three-phase project describes, at a general level, the potential impacts of NISP's
preferred alternative to Poudre River hydrology, geomorphology, hydraulics, fisheries, and
vegetation. It is uncertain if a final draft of Phase I will be ready for distribution to Council by
December 11. Phase II of this project could include a more detailed and refined assessment of the
potential impacts. Phase III would entail a close reading of the DEIS and assistance to staff by the
consultant to help develop comments to the Army Corps.
Economic Survey
The City has contracted with Dr. John Loomis from the Department of Resource Economics at
Colorado State University to conduct a "Contingent Valuation" citizen survey of the "financial
value" of the Poudre River to a Fort Collins citizen. A questionnaire survey has been sent to
approximately 550 households in Fort Collins to determine what a typical citizen would consider
paying to maintain or improve flows in the Poudre River. The survey is consistent with the type of
survey instrument the Army Corps of Engineers uses in Environmental Impact Statements. The
results of the survey will not be available until mid-to-late December.
Water Quality
The Utilities Department is continuing a cooperative flow and water quality program with the U.S.
Geological Survey at key points on the Cache la Poudre including the Lincoln Street and Boxelder
gauges as well as at several points upstream from the mouth of the canyon. That extensive USGS
flow and water quality dataset could be used in evaluating the EIS and corresponding potential
December 11, 2007 Page 3
impacts of NISP on the Poudre River through Fort Collins. USGS flow measurement sites include
a gauge station on the North Fork of the Poudre and gauge stations at and near Joe Wright Reservoir.
In addition,Utilities has established an extensive cooperative monitoring program with the City of
Greeley and the Tri-District Water Plant to establish baseline water quality data both up and
downstream of the mouth of the canyon as well as Horsetooth, Halligan and Seaman Reservoirs.
These long-term monitoring programs are designed to provide the data necessary to ensure effective
and efficient water supply, treatment operations, and water delivery services to our customers.
Potential Impacts to the Poudre River
Through its preliminary work, staff has identified several potentially significant impacts to the
Poudre River through town.
It is extremely important to note that the DEIS and the project proponents may propose extensive
mitigation efforts to counterbalance the potentially negative impacts of NISP on this river reach.
Mitigation in the federal planning process essentially is composed of three elements: avoidance of
negative impacts, minimization of negative impacts, and compensatory actions for environmental
damages caused by the project. NISP mitigation efforts are not likely to be described in much detail
until the release of the DEIS. Thus, staff will be better able to describe and evaluate those efforts
and possible impacts to Council early in 2008.
As described in the key points of"How NISP Works," (see Attachment 1) NISP has the potential
to significantly reduce river flows through town. Any time that flows are substantially reduced in
the Poudre River, there are potentially serious ramifications. In particular, the reduction of peak
flows in the spring and early summer are likely to have a negative impact on a broad spectrum of
biological, scenic, recreational and aesthetic values. In addition, drawdown of flows during the
"shoulder"months prior to and after peak flows also could have deleterious impacts.
More specifically:
1. Reduced peak flows are likely to increase fine sediment build up in the river. This buildup,
over time, can reduce habitat for aquatic species and invertebrates. It also can reduce the
capacity of the channel to carry low-flows,resulting in stagnation during low-flow periods
and increasing the risk of overbank flooding in low-lying areas during major flow events.
2. Lower flows, over time, may increase water temperatures and worsen and/or eliminate the
trout fishery.
3. Reductions in peak flows are likely to reduce opportunities for cottonwood germination and
prevalence of willows. Over time, this could result in a change in tree and shrub dynamics
resulting in a greater dominance of introduced trees such as Russian olive and Siberian elm.
4. Lower flows can result in lower water quality. Lower average daily flows would result in
less water for dilution of pollutants. In addition,lower peak flows would result in both less
water for dilution and less water for natural cleansing of detritus and sediment through
scouring of the riverbed.
December 11, 2007 Page 4
ATTACHMENTS
1. Key points on Historic Poudre River Operations and How NISP Works.
2. Illustration: Potential NISP Flow Reductions.
3. Powerpoint presentation.
ATTACHMENT 1
Key points on Historic Poudre River Operations and How NISP Works
Historic Poudre River Operations
• Water diverted from the river based on prior appropriations doctrine and other
Colorado State water laws
o First in time, first in right
• Numerous diversions on Poudre River
o Direct flow rights go back over 140 years, primarily owned by irrigation
companies and municipalities
o Storage rights more recent, but limited mostly to small upper basin reservoirs
and plains reservoirs
• Colorado-Big Thompson (CBT) Project
o Colorado River water delivered to northeast Colorado primarily for
agricultural and municipal flows
o The project enhances flows in the Poudre through delivery of CBT water to
irrigation companies
o Many CBT components, including Horsetooth Reservoir
o Administered by the Northern Colorado Water Conservancy District
(NCWCD)
• Flows through Fort Collins
o Lincoln Street - USGS flow gage recording since 1975
o Average annual gauged flow is— 112,500 AF/yr (longer term average would
likely be less)
o Compares to average annual (1950-2006) flow at USGS mouth of canyon
gage of—227,700 AF/yr
o Average annual (1950-2006) native flows (without man's influence) at mouth
of canyon of—277,700 AF/yr- would be similar native flow at Lincoln Street
o Fort Collins has junior(1985) in-stream flow rights (from 5 to 30 CFS when
in priority) at Power Plant Dam (Boat Chute) and Nature Center Dam
How NISP Works
• Project coordinated by NCWCD
o Proposed annual yield of—40,000 AF/yr
o Many water providers outside the Poudre Basin
• Two main project components (for their preferred alternative)
o Grey Mountain decree into Glade Reservoir (— 16,000 AF/yr of yield)
o South Platte Water Conservation Project (—24,000 AF/yr of yield)
• Grey Mountain/Glade
o Junior(1980)water right - originally on Poudre River mainstem
o Will only divert once every several years on average
o Glade Reservoir(— 170,000 AF) will be located just north of Ted's
Place on US 287
o Water right diverted into the Poudre Valley Canal (PVC) to a forebay
and pumped into Glade(maximum pumping rate— 1,000 cfs)
• South Platte Water Conservation Project
o Junior (1992) water right - should divert in most years
o Capture flows on South Platte River below Poudre River confluence
o Pumped into Galeton Reservoir(—40,000 AF)
o Galeton releases are pumped into lower 1/3`s of two large irrigation
canals (Larimer &Weld and New Cache)
o Water pumped into canals are exchanged up river into Glade Reservoir
when exchange potential exists
• The"exchange"means that the water that previously flowed
down to these canals will physically be diverted into Glade,
which will reduce flows between these points
• Potential NISP Deliveries to Participants
o Exchange with CBT releases from Horsetooth Reservoir
o Potential pipeline from Glade to Horsetooth Reservoir
o Potential pipeline from Glade to Carter Lake
o Combination of CBT exchanges and pipeline option
• Potential Poudre River Effects. Please see attached illustration"Potential
NISP Flow Reductions" for a graphic representation of the information below.
o — 16,000 AF/yr less from below the New Cache Canal to its
confluence with the South Platte River and beyond
o —28,000 AF/yr less between the Larimer & Weld and New Cache
canals
o — 40,000 AF/yr less between the Poudre Valley and Larimer & Weld
canals
o Most water moved into Glade will be taken from the river in high
runoff months (May, June, July)
o Drop in flows through town (Lincoln Street gage) could be significant,
with an average reduction of around 30-40% per year, with potentially
much higher reductions in certain periods
o SPWCP exchanges cannot violate Fort Collins' in-stream flow rights
o Techniques to minimize the impacts to flows are likely to be presented
in the DEIS
U .S . 287 U . S . 287
# m Northern Alignment NISP "S PREFERRED ALTERNATIVE
GI a de Reseri r
170, 000AF Potential NISP
Mdrn .
Less ~ 28 , 000 AF /yr
-- l ow Red uct ions
GIadi.L tc South Platte Water r . .
Horsd�tawh Conservation Project Galeton F��ser�ir
i �� liaeA U LT\ %L ca 4"00 ELF
- LM
SPVICP p1pam
Horsewo FORT COLLINSResenror
EATO N
Less ~ 40 , 000 AF
FL - �
LCYVELA IV D
Less ~ 16 , 000 AF /yr
ti�
■
rojec
Fort Collins City Council
December 11 , 2007
Worksession
�e resent sin
To inform Council of the work staff is
doing Alvespect tom. North rn
Integrated Supply Project
y To seek Council reactions and
guidance based on this update
Overview of Presentation
I
A review of historic Poudre River
— operations
An overview of how NISP works
An overview of staff work in advance of
the re ease of the Draft Environmental
Impact Statement by the Army Corps of
Engineers
An overview of preliminary concerns
I VPFo
f Pr
Min ation and/or mitigation
me " es will be prQpasad by the
project proponents, or imposed by
the Arm Cor s of Engineers
Those measures will be forthcoming
with the release of the DEIS currently
under preparation by ACOE
4
r�JS 111 "'ic Poludre River
Operations
Diversions based on prior appropriation doctrine
• other CO water laws
rightFirst in time,, first in
Numerous diversions on Poudre, including direc
• storage rights
flowsColorado- Big Thompson (CBT) Project
• Enhances on - Poudre River
• Administered by Northern Colorado Water
Conservancy
North Ne r
+ • Terer XerLhP"droDitch POUDRE RIVER DIVERSIONS
Munroe Canal
N6LNDTON
Paadre Valley Canal
ran CGDInr lanmer Genly Canal
PLPollne
Creole
•.P Nnhron Ditch
Charles Hansonlittle cache uM Taylor isGic DNncA J
L.1
9ePWy Glut I.enmar anal held Gael
P. N [
Wre caul
as 6Mur CryDitch
DNCA TmhaA Nor Wet
I.snmer
NoneLoolA No 2 Dtch AMT
Rese"wr Nw Me=
Caul
PWe.nl Valley
aDd lake Canal TM•ix
Fe i
Ditch C1
Ditch —0
roual heat Cr..l.y Ne 2 CatrA F•TON
wa 1111140, q
sg}
FORT COLILMS
fie^ •Allatey, Ditch
! N Eaton Crny O{il.T Ditch
Ditch Me 2 Catch b!d a
Ten Ditch TP
n DIIr"
call
uw
OREEtiT �S
Nt
3
Fjrs throug Collins
Lincoln Street Gage
. USGS flow gage recording since 1975 (short period )
. Average flow N 112, 500 AF/yr ( longer term average
would likely be less)
Mouth of Canyon Gage
. Average flow N 227, 700 AF/yr ( 1950 - 2006)
. Average native flow N 277, 700 AF/yr ( 1950 - 2006)
. Likely similar native flow at Lincoln Street
o ollins in - channel diversions ( 1985 )
. Power Plant Dam : 5 cfs (9/ 1 -4/30) , 30 cfs ( 5/ 1 -8/31 )
. Nature Center Dam : 5 - 15 cfs (9/ 1 -4/30), 30 cfs ( 5/ 1
8/31 ) dkm�■
Can be called out by more senior r rights
Cache la Poudre River Annual Virgin Flows at the Mouth of the Canyon
800000
700000 Total Annual Flow
Long Tenn Average
600000
500000
w
w
w
Q400000
3
0
LL
300000
200000
100000
0
V OJ N (D O V OJ ry (O O V OJ ry (D O V OJ N (O O V OJ ry (O O V OJ ry (O O V
m m m m Ol m W Ol m W m W Ol m � O� m O m W O� m Ol OJ m Ol m Ol m O O
Year
Cache la Poudre River Annual Flow at Lincoln Street Gage (USGS 06752260)
600,000
500,000 M Total Annual:FlowPeriod Avera1976-2006)
400,000
m
w
ti
m 300,000
3
0
LL
200,000
100,000
I h L
m m W O N M V m (9 r m m O m 0
N M m W r m 0 O N ry V h m
r r r � m m m m OJ m m m m m rn rn w rn rn rn rn rn o 0 0 0 0 0
rn rn rn rn rn m rn rn rn rn rn rn rn rn rn rn rn W rn rn rn rn rn rn o 0 0 0 0 0 0
Year
5
Cache la Poudre River Gages - Average Daily Flows (1976-2005)
1 ,800
1 ,600
1 ,400
1 ,200
1 ,000
u
3
0
0 800
600
400 - A -Y
200
0
'0 0 0 w w 0
�i Q Q Q o 0 o 0 0 0 to y 0 0 0 Z Z Z 0 0 0
Date
Mouth of canyon Gage —Lincoln Street Gage
too •
ion
Project coordinated by NCWCD for rv15
participants district
• main project components •
preferred alternative)
Mountain• Grey decree into Glade Reservoir
( rvl6, 000
• South Platte Water Conservation Project
111
12
N NISP
Participant Boundaries
mcaseToom
IF 2 10
11
LARIMER 1 . . .
S F�IH I
CAROR South /Y�ll: 9
tm 6
SOULDER 1 Fort Collins Loveland Watr District $
3 Windsor
13 3 Len Nand Water District
s7 . 4 E.le
1s �• 5 Evans
6 Connai Wad County Was District
12 , 7 Fort Lvpbn
_ _ _ _ _ _ _ _ _ _ _ _ _ - a Fort Morgan
JEFFERSON - e Morgan County ouauty War«
10 Eaten
11 severance
II LatayeNe
Denver 13 Firestone
Moo
rip 14 Frederick
I 15 Docono
U.S. 287 U.S. 287
wiiFstelignm tNortllxnAlignment
Alignmen NISP'S PREFERRED ALTERNATIVE
ts
Glade Reservoir
170,000 AF
wdimg�on:�
O
Glade to South Platte Water a
Horsetooth 1 Conservation Project
Pipeline r Galeton Reservoir
A Je0
Held ca yt ,Or000 AF
ULT'
SrRry r limm
Horsetooth FORT COLLINS
Reservoir
EATO N
d� Cache Car4F
Cahla Fa�aY[R,Yi
LOVELAND
GREELEY J
t1 ��'RorV�
a^°xes O
7
Grey Mountai jade
grey Mountain right ( 1980 ) can store up to
--2201000 AF
. Originally on Poudre River near canyon mouth
y Glade Reservoir ( " 170 , 000 AF) : located just
north of Ted 's Place
15
Grey ffou / Glade
Water rights diverted into oudre Valley CM
( PVC) to a forebay and pumped into Glad
. Maximum pump rate N1 , 000 cfs
Projected to only store once every several years
(on average) under Grey Mountain right
1 � ,
F �
f ! .
4701
r
N aNO edeplace
F
FF
S
Legend Northern Integrated Supply project 111;1,,, �,.,,,,
vuceo uWE �rmw , HW 287 Relocation Final Alternatives
QIIL a,v9n9wy os m
Om manro t u \,
O W s soaa i as mo
Dowmma
flowsSPWCP
Water right ( 1992 ) to capture South Platt
River • Poudre River confluenc
Should • in most ' •
Water • to • • •
( rA01000 AF) for storage
Galeton releases pumped into lower 1 / 3 d
of • large irrigation canals
Larimer • Weld and New Cache Canals
9
P.r0jjA.e. j v
AAkXC �� � ' • l r ' 1
exchange potential
' • ' meanswater
previously • ' • down to these canals
physically be diverted • Glade ,
reduce flowsbetween •
South Platte Water
Conservation Project Galeton Reservoir
&,Need Carnal 40,000 AF
AULT �r�`
SPWCP Pipeline
FORT COLLINS
�24,000 AF/yr
Can pump cac Ca
directly to canals
C.,he la Roudre River
LOVELAND
GREELEY ro Al
0
fie9i�e�
10
South Platte Water
Conservation Project Galeton Reservoir
A2,000 AF/yr 40,000 AF
AULT �
FORT COLLINS
EATON
Nev+ C-ache a/
cache b Poodle River
A2,000 AF/yr
LOVELAN D
GREELEY
m
Q� u
B-
Glade
Reservoir Joint Operations
of Glade Reservoir
5- 000 and Galeton Reservoir
of
koh
i�>o � Galeton
Caere / P Reservoir a
%% 5,000 of
,� With NISP 10,000 of J Total
N 15,000 of
Wit hout NISP total 15,00 of �
Ag lands
Water deliveries with NISP
------- Without NISP
�a
11
Pote ial NISP Deli �r
Participants
� Exchange with CBT releases from
Horsetooth Reservoir
� Potential pipeline from Glade to
Horsetooth Reservoir
P ten � pipeline from Glade to Carter
Lake
� Combination of CBT eX�hanges an
pipeline� ption
Alignment
Alignment
Glade
Wellington
Glade to
Horsetooth
Pipeline
Horsetooth FORTCOLLINS
Reservoir
24
12
ESTIMATED TIMELINE ,
ENVIRONMENTAL PERMITTING : 2004 - 2007
GLADE DESIGN : 2008 - 2009
GLADE CONSTRUCTION : 2009 - 2013
GLADE OPERATIONAL : 2013
SPWCP DESIGN : 2013 - 2014
SPWCP CONSTRUCTION : 2014 - 2017
SPWCP OPERATIONAL : 2019
Potential
Reduction in flows
. 1 1 1 from - r � - -Greeley
: 111 from : to New Cache
canals
41 111 ARAfrom ' • • - Valley to
canals
13
U.S. 287 U.5. 287
Western t "°rthernAlig°n,ent Alignment NISP'S PREFERRED ALTERNATIVE
Glade Reservoir
� Potential NISP
170,000 AF ems" ^pwma
Less —28 , 000 AF/yr Flow Reductions
Glade to South Platte Water
Horsetooth I Conservation Project
Pipeline Galeton Reservoir
b,Netd tanw 401000 AF
AU LT �a°�e' vwo n
Horsetoo FORTCOLLINS
Reserwir
EATO N
f] Neo Cache Caryl
Less —40 , 000 AF/yr
. _ o
LOVELAND
GREELEY
$ Less — 16 , 000 AF/yr
11 eie, ,
Potential NISP Effects
Most water moved into Glade will occur
during high runoffmonths
StreetReduced flows through town ( Lincoln
gage)
• • ' annual drop of • •
• Potentially greater reductions during certain
periods
14
Potential NIS&ftffects
SPWCP exchanges cannot violate Fort
Collins' in - channel divebn rights
Draft environmental impact statement
( DEIS) due in next few months
. Model results should show more
definite im acts
. Some meth ds to minimize flow impac
will likely be presented
Alternatives to proposed project will
be considered in ISP permitting
process 2
Average Daily Flow at Lincoln Street Gage
1 ,200
1 ,000
800
600
200 L j
Date
GagedHistoric � � .
Average Daily Flow at Lincoln Street Gage
Potential Changes due to NISP
1 ,200
1 ,000
800
N
U
3 600
0
LL
400
200
0
> j N N U V O 0 N N N
LL LL Q Q Q Q fA (A � N ob � Z Z 2 o m.
�
N N N N N N N N th
Date
Historic Gaged (1976-2006) — Potential Post-NISP Gaged
Annual Flows at Lincoln Street Gage
600,000
500,000
400,000
LL
a
0
0
LL 300,000
3
C
C
Q 200,000
100,000
0
co r m m o N ch v �n co r m m o N ch v in co r m rn o
r r r r m m m m m m m m m m rn m rn m rn m m m m rn o 0
m m m m rn m rn m rn m m rn m rn m m m m m m m m m m o 0
Year
IN Historic Gaged
16
Annual Flows at Lincoln Street Gage
Potential Changes due to NISP
600,000
500,000
400,000
LL
Q
3
0
LL 300,000
c
c
Q 200,000
00,000
0
1 1 1 S n , RI I HI
`r° � � °r' m m m ro m ro ro in ro m rn m w m rn m m m m rn o 0
N N
Year
■ Potential Post-NISP Gaged ■ Potential Grey Mountain Diversions ❑ Potential SPWCP Exchanges
Monthly Flows at Lincoln Street Gage (Wet Year - 1980 )
Potential Changes due to NISP
180,000
160,000
140,000
m 120,000
m
`u
a 100,000
0
0
LL 80,000
P
`o 60,000
40,000
20,000
0
C T C OI 0_ V 7 U
li W W O O W
Q
Q n Z 0
Month
❑ Historic Monthly Average ■ 1980 Gaged ■ Potential Post-NISP Gaged
17
Monthly Flows at Lincoln Street Gage ( Dry Year - 1989 )
Potential Changes due to NISP
70,000
60,000
50,000
w
w
w
40,000
3
0
a 30,000
r
c
0
20,000
10,000
0
a o d o 0
n z ❑
Month
❑ Historic Monthly Average ■ 1989 Gaged ■ Potential Post-NISP Gaged
Monthly Flows at Lincoln Street Gage (Avg . Year - 1996)
Potential Changes due to NISP
70,000
60,000
w 50,000
v
w
v
40,000
IL
0
LL
30,000
t
c
0
20,000
10,000
0
o- W
LL < g Q to O z ❑
Month
❑ Historic Monthly Average ❑ 1996 Gaged ■ Potential Post-NISP Gaged
18
Ilig am an Weterwi
em t
Project being de elope by Fort Collins
and Greeley
■ Currently in NEPA permitting process
Enlarge existing reservoirs on North Fork
of Poudre
■.JJafligan (existing 6 , 400 AF to 40 , 000 AF)
. Seaman (existing 5 , 000 AF to 53 , 000 AF)
37
H,Vjpqpoaman
Mana t Pr4je
Fort Collins partnering with Tri - Districts ( EL
FCLWD, and NWCWD) and North Poudre
Irrigation Company
v Reservoirs will mostly store converted irrigation
rights from ditches above downtown Fort Collins
. Less impact to flows through town
Proposed Enlarged
ic"q a W ca"I Halligan Reservoir
Proposed Enlarged
Milton-Seaman Reservoir
YAIn S••�yc
RcaFnot 0 Pd'AOeP
It+Ja Qaavl Wetlinoan o 8 Nallonal
H, .. • S
Gra%lands
/TOOaWm Q V'unii
-j- � Halligan-Seaman
Water Management
Fort Project
Collins
I :1i, lie
Bb}!L 'A inil aq
- � La F.:•dv Xn. .
4AG TMopifte i� $
cland
I
IV iao gw•nn '
Ip Kcr¢v
E FIV R�rt
r � •
• Rive - n i c
Evaluation of Hydrologic Modeling
aW,,Potential Impa es
• _
EconomicSurveyWnfor • 1 17My
20
Preliminary Concerns
Extremely important to note tha
minimization and mitigation me sures
will be propose
y Staff has focused on the river reach
from Overland Trail to I - 25
Overall staff concerns are related to
reduced instreaam flows, in particular
peak flows duri to spring and
early summer
i na ry Concerns
I
Reduced peak flows are likely to
increase fine sediment W40
river . This buildup, over time , cqr
reduce habitat for aquatic species and
invertebrates . It also aMeduce the
capacity of the channel to carry low
flows, resulting in stagnation duOs g
low-floo periods an )*easing the
risk of overbank flooding in low- I in 42
Y g
-% ram -% ram AI IVir� n PuVn on ; ter fIr%% AI r%1, i� r�#tom
Preliminary Concerns
ower flows, over time, may increase
water temperatures aed worsen
and/or eliminate the trout fishery
i nary Concerns
Redu io ak flows are Lely to
rd= oppo itW.9p cottowood
germination and prevalence Oft
willows . Over time, this could result
in a-ehange in tree an rub
dynamics resulting in a greater
dominance of introduced trees such
as Russian olive and Siberian elm .
44
Preliminary Concerns
r flows can rest in lower water
quality . Lower aver-age 'dally flows
woulojesult in less water for dilution
of poliltants . In addition , lower peak
flows would result in both less water
for dilution and less water for natural
clean ing of detritus and sedir ,
through scouring of the riverbed .
9 g
45
' nary Concerns
In addition to the ecological im a
there will be impacts rely
recreation and aesthetics .
Next
Continue analytic work
y Review draftS wlleased
y Prepare comments for Council
consideration