HomeMy WebLinkAboutCOUNCIL - AGENDA ITEM - 01/19/2016 - ITEMS RELATING TO REVISIONS OF CERTAIN DETENTION AAgenda Item 5
Item # 5 Page 1
AGENDA ITEM SUMMARY January 19, 2016
City Council
STAFF
Basil Hamdan, Civil Engineer II
Ken Sampley, Stormwater/Floodplain Program Mgr
Kevin Gertig, Utilities Executive Director
Jon Haukaas, Water Engr Field Operations Mgr
SUBJECT
Items Relating to Revisions of Certain Detention and Development Policies in the Fort Collins Stormwater
Criteria Manual.
EXECUTIVE SUMMARY
A. Second Reading of Ordinance No. 006, 2016, Amending Chapter 26 of the Code of the City of Fort Collins
and the Fort Collins Stormwater Criteria Manual to Modify the Criteria for Underground Detention Systems.
B. Second Reading of Ordinance No. 007, 2016, Amending Chapter 26 of the Code of the City of Fort Collins
and the Fort Collins Stormwater Criteria Manual to Modify Provisions Implementing Low Impact
Development Principles.
These Ordinances, unanimously adopted on First Reading on January 5, 2016, formally adopt two updates to
the Stormwater Criteria Manual. Ordinance No. 006, 2016, updates the criteria that govern when, where, and
to what extent it is appropriate to design and construct underground stormwater detention systems in the City
of Fort Collins. Ordinance No.007, 2016, updates the current Low Impact Development (LID) criteria. The two
policies are consistent with sustainability goals for the City of Fort Collins which center on three themes:
innovate, sustain and connect. The adoption of these updated policies will allow for more efficient use of
space, thus allowing the City to meet its sustainability goals, provide innovative design flexibility for new
development that will enhance community affordability and livability, and allow a more compact development
pattern in Fort Collins enhancing connectivity and reducing sprawl.
STAFF RECOMMENDATION
Staff recommends adoption of the Ordinance on Second Reading.
BACKGROUND / DISCUSSION
On First Reading, Council unanimously approved the ordinance amending the Stormwater Criteria Manual to
update the Underground Detention Policy and the Low Impact Development (LID) Policy respectively.
During Council Discussion of the Consent Agenda items questions were asked by Council Members, namely:
How do we quantify benefits due to the changes in the manual regarding the quality/quantity of
stormwater?
The benefits of the volume reduction and water quality treatment that will be accrued through this policy update
are incremental. By increasing the level of LID required for proposed development sites, the updated policy will
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increase the LID-treated runoff volume which will have corresponding increases in water quantity and quality
benefits.
The monitoring program funded by the City and conducted by Colorado State University has provided the City
with valuable data and insight with respect to the water quality and quantity benefits of different types of LID
technologies under local conditions. That data shows flow volume reductions in the range of 30 to 60% for the
smaller storms using different types of LID measures (mainly bioretention and permeable pavements). The
water quality data collected and analyzed by CSU also shows a considerable amount of reductions in pollutant
loads discharged out of LID-type facilities into the City’s Receiving Waters and streams. Pollutant load
reductions were observed to be in the range of 80 to 95% level for Total Suspended Solids (TSS), nutrients
(Nitrogen and Phosphorous) and various metals (Copper, Zinc and Chromium). The most effective technology
measures in that regard were, once again, permeable pavement and bioretention.
This monitoring program, which was initiated in 2011 and continues to this date, is one of the few data based
wet-weather monitoring programs for LID-based technologies and puts the City in a favorable position in
meeting the upcoming state nutrient loading regulation known as Regulation 85.
Finally, the updated policy, by providing more options as to how this treatment level can be achieved, will result
in more performance based outcomes and measures being implemented in the field rather than being process
driven and forcing a certain technology to be used and thus increasing implementation costs. That in turn will
allow the City to remain a leader in innovative LID treatment as new technologies are developed by the
industry and become mainstreamed. The City intends to develop a guidance document that will look at
different scenarios and options that could be used for different types of development sites to help practitioners
in that regard. This guidance document could then be updated on a regular basis as new technologies come
online.
When do we know that we have reached a finalized policy document that will serve the City over the long
term?
The City intends to remain a leader in the field of sustainable infrastructure and will be looking at fine-tuning its
policies with that goal in mind. The current update is considered an interim update as more discussions are
planned in the future through the LID Roundtable discussions. These discussions are scheduled to conclude
by June 2016 and will guide the City on whether any further updates are necessary in the short term. Since
the inception of the original LID Policy in February 2013, the City has committed that it would look at the
current LID policy as being subject to its commitment to continuous improvement. As such, the City will remain
open to further updates as implementation of the policy provides guidance for future needed updates as part of
a “plan, do, check” process aimed at gaining knowledge from experience and revising policies to respond to
the public interest and in order to meet and exceed federal and state mandates with respect to water quality
treatment.
ATTACHMENTS
1. First Reading Agenda Item Summary, January 5, 2016 (w/o attachments) (PDF)
2. Ordinance No. 006, 2016 (PDF)
3. Ordinance No. 007, 2016 (PDF)
Agenda Item 10
Item # 10 Page 1
AGENDA ITEM SUMMARY January 5, 2016
City Council
STAFF
Basil Hamdan, Civil Engineer II
Ken Sampley, Stormwater/Floodplain Program Mgr
Kevin Gertig, Utilities Executive Director
Jon Haukaas, Water Engr Field Operations Mgr
SUBJECT
Items Relating to Revisions of Certain Detention and Development Policies in the Fort Collins Stormwater
Criteria Manual.
EXECUTIVE SUMMARY
A. First Reading of Ordinance No. 006, 2016, Amending Chapter 26 of the Code of the City of Fort Collins
and the Fort Collins Stormwater Criteria Manual to Modify the Criteria for Underground Detention Systems.
B. First Reading of Ordinance No. 007, 2016, Amending Chapter 26 of the Code of the City of Fort Collins
and the Fort Collins Stormwater Criteria Manual to Modify Provisions Implementing Low Impact
Development Principles.
The purpose of this item is to formally adopt two updates to the Stormwater Criteria Manual. Ordinance No.
006, 2016, updates the criteria that govern when, where, and to what extent it is appropriate to design and
construct underground stormwater detention systems in the City of Fort Collins. Ordinance No.007, 2016,
updates the current Low Impact Development (LID) criteria. The two policies are consistent with sustainability
goals for the City of Fort Collins which center on three themes: innovate, sustain and connect. The adoption of
these updated policies will allow for more efficient use of space, thus allowing the City to meet its sustainability
goals, provide innovative design flexibility for new development that will enhance community affordability and
livability, and allow a more compact development pattern in Fort Collins enhancing connectivity and reducing
sprawl.
STAFF RECOMMENDATION
Staff recommends adoption of the Ordinances on First Reading.
BACKGROUND / DISCUSSION
Updated Underground Detention Policy
The City of Fort Collins adopted an updated Stormwater Criteria Manual (Manual) on December 20, 2011 (Ord.
No. 174, 2011), adopting by reference certain portions of the Urban Storm Drainage Criteria Manual, 2001
Edition published by the Denver Urban Drainage and Flood Control District, a widely applied and referenced
set of storm water-related standards along with a separately codified set of extensive amendments
customizing the standards, policies and practices of the Urban Drainage Manual for use in Fort Collins (“Fort
Collins Amendments”), all as set forth in City Code Section 26-500. Unless an amendment to the Manual is a
purely technical revision in nature, modification of the Fort Collins Amendments must be approved by City
Council. The Utilities Executive Director may otherwise approve limited technical revisions to the Manual.
ATTACHMENT 1
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Currently, under the City Code and the Manual, underground detention is only allowed at the discretion of the
Utilities Executive Director as an exception, with such approval subject to separate construction, operation,
and maintenance conditions. The City can advance the interest of its Stormwater Utility customers and
facilitate development in the community by adjusting the current underground detention policy in the Manual to
recognize an explicit set of system criteria that ensure construction and maintenance of such systems are
conducted in a consistent, safe, maintainable, and effective manner.
Purpose and Benefits of Underground Detention
The need to revise the policy involving underground detention facilities arose in conjunction with adoption of
the Low Impact Development (LID) Policy by the City in March 2013. The LID policy is aimed at encouraging
sustainable practices in stormwater management. LID practices, sometimes also referred to as “Green
Infrastructure” (GI), generally encourage infiltration of runoff to reduce volume and improve water quality.
LID or GI is a comprehensive land planning and engineering design approach to managing stormwater runoff
with a goal of replicating natural systems that existed prior to development. LID techniques treat and control
stormwater at its source, thereby reducing the need for large structures or end-of-pipe treatment.
Since LID practices encourage infiltration systems, prohibition of underground detention is contrary to that
goal, which has led to the current proposed update to the underground detention policy.
Proposed Underground Detention Policy
The proposed underground detention policy is intended for use only where surface detention is deemed
impracticable. When applicable, the proposed policy allows underground detention under the following
conditions:
It must be safe, i.e., it must not cause flooding to nearby public or private property
It must be efficient, i.e., it must provide effective water quality treatment.
It must be accompanied by an approved Standard Operations Procedures (SOPs) manual that will
ensure appropriate maintenance practices are followed by all owners of the facility
It must have a gravity driven outfall system
It must be relatively small in volume, i.e., not exceed 1 acre-foot
It must preserve downstream water rights
It must be inspected regularly
It must be designed with maintenance in mind
It must comply with all other technical criteria as specified
Updated Policy Development Process
The underground detention policy was developed after extensive consultation in coordination with practicing
stormwater engineering and development professionals in the City of Fort Collins. The City’s Water Board
reviewed the proposed policy at its regular meeting on November 19, 2015, and voted unanimously to
recommend City Council adopt the updated policy, including additional technical criteria specified by the
Board. (Attachment 1).
Updated Low Impact Development Criteria
As discussed above, an element of the integrated stormwater management system established under the Fort
Collins Stormwater Criterial Manual is the application of LID criteria to facilitate distributed and landscaping-
based stormwater runoff management. In conjunction with the updated underground detention policy, staff has
recommended the LID criteria set forth in Section 3.1 of Volume 3, Chapter 2, Paragraph K of the Fort Collins
Amendments be clarified as to when they are applied.
Agenda Item 10
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The focus of the updated criteria is to clarify that LID techniques need to be applied on any newly developed or
redeveloped site and any modification of impervious area on a previously developed site for which a
development construction permit is required under City codes and regulations.
Background
Fort Collins Utilities staff has met with the Chamber of Commerce and representatives from the development
community and engineering consultants to consider updates to the LID Policy in response to concerns raised
to City Council and the Chamber of Commerce in the last several months. Meeting summary notes from the
Chamber presentation are appended as Attachment 3. Staff also engaged community roundtables on
November 18 and December 16, 2015, after which further revisions were made to the proposed LID Policy
update (see Roundtable summary memo, Attachment 2). The main concern presented to staff during these
engagements has been the high initial cost for the permeable pavement component of the existing policy.
The current LID Policy was adopted in February 2013 and has been in effect since March 1, 2013. It is
outlined in Volume 3 Chapter 3 of the Fort Collins’ Stormwater Criteria Manual, as reflected in Attachment 4.
The current policy states: at least fifty percent (50%) of a site must be treated by an LID technique when a
minimum of twenty-five percent (25%) of the driving or parking area in parking lots is constructed with a
permeable pavement system that functions as an LID technique. An alternative compliance clause is also
included that allows variation from these standards when these conditions cannot be met due physical site
constraints, and an equal or better alternative is provided.
When the policy was first adopted in 2013, initial cost issues were considered; however, the decision to
proceed with the current regulations as stated in the policy were driven by life cycle costs analysis and
considerations which show that over the life cycle of the project the LID treatment type design tends to be
more economical than conventional solutions.
Proposed Policy
In response to development concerns, the City is proposing a revision to the LID criteria providing options that
offer a wider range of design solutions to better fit the type of development under consideration (i.e.
“greenfield” versus highly-developed infill).
The proposed policy will ensure the technologies used in the treatment of proposed developments are still in
concert with the City’s overall sustainability goals. Under the updated LID policy, three options would be
allowed:
Under the first option the required amount of LID treatment is increased from 50 to 75% of the new
development and redevelopment area and removes the permeable pavement requirement when a
75% LID treatment level is provided.
The second option allows the amount of LID treatment to remain at the currently required 50% level,
provided a permeable pavement system is constructed on at least 25% of the drivable pavement area
in any development. This option was added to encourage this type of technology when space
constraints do not allow for a higher level of LID treatment and encourages the dual use of parking lots
as a usable development area as well as a water quality treatment component. It is also based on
studies that show that permeable pavement in general provides a higher level of pollutant removal
rates.
The third option maintains the alternative compliance option that allows the Utilities Executive Director
to vary some of the requirements when site engineering constraints do not allow the for the
construction of LID techniques as prescribed in the first two options. This allows for a staff level
interpretation of the LID regulations, as long as an “equal or better” level of water quality treatment is
deemed to be achieved and increases the level of flexibility in how that level is accomplished. This is
an important consideration when designing an LID treatment system because site conditions often
dictate what can be constructed based on constraints unique to each site.
Agenda Item 10
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This LID Policy update taken in conjunction with the Underground Detention Policy update will provide an
incentive for developers to use pervious pavement system as a water quality treatment option when land costs
are a major consideration.
BOARD / COMMISSION RECOMMENDATION
At its regular November 19, 2015 meeting, the Water Board considered staff’s recommendation regarding the
underground detention policy, and voted unanimously to recommend City Council adopt the updated policy,
including additional technical criteria specified by the Board. (Attachment 1).
At its December 17, 2015 meeting, the Water Board considered staff’s recommendation regarding the LID
updates and unanimously voted to recommend Council adopt the updated LID criteria for the Fort Collins
Stormwater Criterial Manual, with some suggested language changes. The Water Board’s suggested changes
and clarifications have been incorporated into the proposed ordinance language.
PUBLIC OUTREACH
Staff has met with Councilmembers, the Fort Collins Chamber of Commerce and representatives of the
development industry and design professionals (Attachment 3). A LID Policy Roundtable meeting was held on
November 18, 2015. Staff listened to concerns from the Chamber of Commerce on December 4, 2015 and
has responded to the issues that were brought up at that meeting.
After meeting with Roundtable participants again on December 16, 2015, staff made further revisions to the
LID Policy update based on those discussions (Attachment 2). Staff presented the revised LID policy for
Water Board review and discussion on December 17, 2015, at which time the Board recommended Council
approval of the revised policy. Staff intends to continue discussions with key stakeholders in the upcoming
months to work on further updates to the policy, if needed.
ATTACHMENTS
1. Water Board minutes, November 19, 2015 (draft) (PDF)
2. LID Policy Update Roundtable Discussion, November 18, 2015 (PDF)
3. Chamber of Commerce Discussion notes, December 4, 2015 (PDF)
4. Current LID Policy (PDF)
5. Water Board Minutes, December 17, 2015 (draft) (PDF)
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ORDINANCE NO. 006, 2016
OF THE COUNCIL OF THE CITY OF FORT COLLINS
AMENDING CHAPTER 26 OF THE CODE OF THE CITY OF FORT COLLINS
AND THE FORT COLLINS STORMWATER CRITERIA MANUAL
TO MODIFY THE CRITERIA FOR UNDERGROUND DETENTION SYSTEMS
WHEREAS, on December 20, 2011, the City Council adopted Ordinance No. 174, 2011,
which amended certain sections of Chapter 26 of the City Code and adopted a set of technical
criteria governing the design and performance of stormwater improvements and related practices
by adopting by reference certain portions of the Urban Drainage and Flood Control District
(“UDFCD”) Criteria Manual, 2001 Edition, published by the Denver Urban Drainage and Flood
Control District, as modified by the Fort Collins Amendments, also adopted by Ordinance No.
174, together referred to and codified as the Fort Collins Stormwater Criteria Manual (the
“Manual”); and
WHEREAS, the Manual, including the separately codified Fort Collins Amendments, has
been modified from time to time by limited technical revisions adopted administratively by the
Utilities Executive Director and filed with the City Clerk as authorized by in City Code Section
26-500; and
WHEREAS, as adopted with the Fort Collins Amendments, the Manual currently
prohibits underground detention as a stormwater management practice, except upon special
review and exception granted at the discretion of the Utilities Executive Director; and
WHEREAS, as part of recent reviews of the City's Municipal Separate Stormwater
System, and in an effort to align the Manual with Low Impact Development policies adopted by
City Council in March 2013, City staff has developed a new amendment to the Manual that
establishes detailed underground detention system criteria (“UDS amendment”); and
WHEREAS, the purpose of the UDS amendment is to facilitate appropriate use of
underground stormwater detention as a best management practice, ensuring predictable, safe,
maintainable, and effective construction and maintenance of such systems; and
WHEREAS, the UDS amendment was presented to the Water Board at its November 18,
2015, regular meeting, and the Board voted unanimously to recommend City Council adoption
of the amendment; and
WHEREAS, the City Council finds that amending the Manual to facilitate predictable
and appropriate construction and maintenance of underground stormwater detention systems,
based on documented review criteria, benefits the City’s citizens and Stormwater Utility
customers by creating a regular process to accommodate such systems.
NOW, THEREFORE, BE IT ORDAINED BY THE COUNCIL OF THE CITY OF
FORT COLLINS as follows:
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Section 1. That the City Council hereby makes and adopts the determinations and
findings set forth in recitals above.
Section 2. That Paragraph 4.16 of Volume 2, Chapter 10, Section H of the Fort
Collins Amendments, which is a component of the Fort Collins Stormwater Criteria Manual, is
hereby amended to read as follows:
4.16 Underground Detention
4.16.1 Policy
The use of structural underground detention is generally discouraged, except when the criteria set
forth in 4.16.2 are satisfied. Underground BMPs should not be considered for detention storage
when surface-based systems are practicable. The system owner must demonstrate that surface-
based detention or other BMPs have been thoroughly evaluated and found to be infeasible before
an underground system is proposed. If an underground storage system is proposed, a system
owner must seek approval of such a system by the Utilities Executive Director, who may
approve such a system upon a determination that the requirements of 4.16.2 are satisfied and that
no adverse impacts are expected to result from the proposed system.
4.16.2 Underground Detention Criteria.
The purpose of this subsection is to set forth technical criteria to be utilized for the use of
underground stormwater detention as a structural BMP to meet water quality and/or
stormwater runoff detention requirements.
(a) All systems.
Any proposed underground stormwater detention system, including gravel
reservoirs in porous interlocking concrete pavement (PICP) systems and
chambers or pipes, shall satisfy the following design and operating criteria:
1. The system owner shall provide to the City a Standard Operating
Procedures (SOPs) Manual detailing the operation and maintenance of the
proposed system. The SOPs Manual must comply with approved and
updated operational and maintenance procedures maintained by the City
for different types of underground detention systems. The SOPs Manual
must be submitted to and approved in written form by the Utilities
Executive Director prior to system approval and operation. A final copy of
the approved SOPs Manual must be maintained on-site by the party
responsible for facility maintenance. Annual reports must be prepared and
submitted to the City detailing the results of the maintenance program (i.e.
inspection dates, inspection frequency, volume loss due to sedimentation,
corrective actions taken, etc.);
2. Runoff must flow through a pre-treatment facility before it enters the
underground detention system;
3. A gravity outfall is required at the invert, i.e. lowest point, of the
underground detention system;
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4. An observation well is required at the downstream end with a perforated
stand pipe, as well as a redundant overflow inlet located in a sump
condition. The redundant inlet must be designed with pre-sedimentation
control at the upstream end of the inlet;
5. The water table level must be documented to be at least one foot (1’)
below reservoir bottom during the high groundwater period of the calendar
year;
6. Where underdrain drainage systems are needed, due to underlying soil
conditions, the underdrain pipe diameter shall be at least eight inches (8”).
Underdrain cleanouts are required at all changes in direction or elevation
locations. If the minimum underdrain size (8”) results in a release rate
larger than allowed under this Manual, a restrictor plate must be added at
the point of outflow;
7. Potential lateral movement of detained storage water outside the limits of
the detention storage reservoir must be controlled, accounted and designed
for in a manner that ensures the structural integrity of adjacent structures
and infrastructure;
8. Infiltration testing must be performed during installation of open
bottom/infiltrating systems, after excavation is complete and before rock
placement in reservoir. These results must be submitted to the City and
approval obtained before commencement of construction activities on the
underground detention facility(ies). If the underground detention reservoir
is intended to allow for infiltration, the bottom of the reservoir must be
protected during construction to minimize compaction;
9. Annual visual inspection is required for all underground detention
systems. Documentation verifying inspection and performance must be
provided to the City within four (4) weeks after completion of annual
inspection. These inspection reports must be filed and available at the City
of Fort Collins Utilities office;
10. The underground detention system owner must submit for review a deed
restriction on the affected real property, incorporating the SOPs and
penalties specified for lack of performance. SOPs must be included in the
site’s Development Agreement, as well as in the deed restriction, subject
to review by the City Attorney’s Office. The deed restriction must
provide for the continued, long term operation and maintenance of the
underground detention system by subsequent owners of the affected
property and must be fully executed by the owners of the affected property
and recorded prior to system approval and operation; and
11. The deed restriction must also provide that if the City deems that the
underground detention system is not being maintained in accordance with
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the SOPs specified in the deed restriction, and the system owner has been
given written notice and at least ten (10) days to cure and has not done so,
the City shall have the right of entry to the property in order to maintain
the system. The City may then charge the owner the time and material
costs incurred by the City to take corrective action and maintain the
system, in addition to any administrative costs incurred by the City.
(b) Detention reservoirs located in gravel void spaces of PICP systems.
In addition to the criteria set forth in 4.16.2 (a), the following additional criteria
apply to any Porous Interlocking Concrete Pavement (PICP) system with a gravel
layer void space:
1. The maximum water quantity detention volume allowed in the subsurface
void space is the greater of 0.2 acre-feet or 20% of the total water quantity
and water quality detention required. The maximum total detention storage
volume to be accounted for in the void space of gravel reservoirs shall be
less than 1.0 acre-foot. Additional storage volume is allowed in chambers
or pipes or a combination of all the system methods;
2. The material specified in the reservoir storage layer must comply with
ASTM Number 2 specifications for rock aggregate, or an alternate
approved in writing by the Utilities Executive Director. A 30% ratio for
available storage volume in the reservoir layer must be used in volume
calculations in order to account for potential sedimentation;
3. A minimum 13,500 pound-force vibratory plate compactor with a
compaction indicator and/or a minimum 10-ton vibratory roller must be
used to compact the system;
4. A PICP parking lot surface must be designed with a minimum 0.5% slope.
All systems must be designed to account for volume detained based on the
physical site characteristics and the ability of the system to intercept that
volume; and
5. Maintenance vacuuming must be performed in accordance with the
approved SOPs for the system. Any infiltration test on the system must be
done in accordance with ASTM C1781. Surface infiltration testing
locations must be indicated on a site map provided to the City pursuant to
Section 4.16. If testing shows an average infiltration rate in excess of one
hundred inches per hour (100”/hr.), vacuuming may occur at six month
intervals. In no instance shall a system be vacuumed less than once each
calendar year.
(c) Detention storage in chambers or pipes.
In addition to the criteria set forth in 4.16.2 (a), the following additional criteria
apply to any storage system using underground chambers and/or pipes:
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1. All chambers or pipes must be placed with a minimum slope of 0.2%;
2. Maintenance access must be provided at point of inflow and point of
outflow into the system. The access must be such that it would allow
human access to inspect the functioning of the storage;
3. All pipes or chambers must be vacuum truck accessible through manholes;
4. An underdrain system is recommended for open bottom chambers if the
soil underlying the storage reservoir does not consist of either Type A or
Type B soils;
5. The minimum pipe size allowed for detention in pipes is fifteen inches
(15”);
6. The structural system capacity must be designed to support AASHTO
HS20 (fire truck) loading, as well as anticipated lifetime AASHTO 18,000
lb. equivalent single axle loads (ESALs); and
7. The system must be inspected at least once every five (5) years using
remote video technology. A written record of this inspection must be
submitted to the Utilities Executive Director.
Introduced, considered favorably on first reading, and ordered published this 5th day of
January, A.D. 2016, and to be presented for final passage on the 19th day of January, A.D. 2016.
_________________________________
Mayor
ATTEST:
_____________________________
City Clerk
Passed and adopted on final reading on the 19th day of January, A.D. 2016.
_________________________________
Mayor
ATTEST:
_____________________________
City Clerk
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ORDINANCE NO. 007, 2016
OF THE COUNCIL OF THE CITY OF FORT COLLINS
AMENDING CHAPTER 26 OF THE CODE OF THE CITY OF FORT COLLINS
AND THE FORT COLLINS STORMWATER CRITERIA MANUAL
TO MODIFY PROVISIONS IMPLEMENTING
LOW IMPACT DEVELOPMENT PRINCIPLES
WHEREAS, on December 20, 2011, the City Council adopted on second reading
Ordinance No. 174, 2011, amending certain sections of Chapter 26 of the City Code to adopt a
set of technical criteria governing the design and performance of stormwater improvements and
related practices, referred to as the "Fort Collins Stormwater Criteria Manual"; and
WHEREAS, the Fort Collins Stormwater Criteria Manual consists of certain portions of
the Urban Storm Drainage Criteria Manual, 2001 Edition published by the Denver Urban
Drainage and Flood Control District (the "Urban Drainage Manual"), a widely applied and
referenced set of storm water-related standards adopted by reference, and a separately codified
set of extensive amendments customizing the standards, policies and practices of the Urban
Drainage Manual for use in Fort Collins (the “Fort Collins Amendments”), all as set forth in
Section 26-500 of the City Code; and
WHEREAS, the Fort Collins Stormwater Criterial Manual, including the separately
codified Fort Collins Amendments, has been modified from time to time by limited technical
revisions adopted administratively by the Utilities Executive Director and filed with the City
Clerk, as authorized by Section 26-500 of the City Code; and
WHEREAS, one element of the integrated, sustainable stormwater management system
established under the Fort Collins Stormwater Criterial Manual is the use of low impact
development (“LID”) criteria to require and encourage more distributed and landscaping-based
stormwater runoff management and control relying on filtration and infiltration to treat and
manage stormwater runoff; and
WHEREAS, staff has recommended that the LID criteria set forth in Section 3.1 of
Volume 3, Chapter 2, Section K of the Fort Collins Amendments be amended to clarify the Low
Impact Development Criteria set forth therein; and
WHEREAS, the City’s Water Board considered staff’s recommendation at the Board’s
regular meeting on December 17, 2015, and voted to recommend City Council adopt such
amendments to the LID criteria in the Fort Collins Stormwater Criteria Manual; and
WHEREAS, Council has determined that the adoption and implementation of this
Ordinance amending the LID criteria set forth in the Fort Collins Amendments to the Urban
Drainage Manual will promote the purposes of the Stormwater Utility and the City and will
further facilitate the holistic and integrated management of stormwater in Fort Collins.
NOW, THEREFORE, BE IT ORDAINED BY THE COUNCIL OF THE CITY OF
FORT COLLINS as follows:
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Section 1. That the City Council hereby makes and adopts the determinations and
findings contained in the recitals set forth above.
Section 2. That Section 3.1 of Volume 3, Chapter 2, Section K of the Fort Collins
Amendments, which is a component of the Fort Collins Stormwater Criteria Manual, is hereby
amended to read as follows:
3.1 Low Impact Development Criteria
Once the WQCV has been calculated in accordance with the specifications of Section 3.0
of this chapter, the total WQCV must be treated by one or more of the methods outlined
in Volume 3, Chapter 4, Treatment BMPs. In addition, the requirements set forth below
in this Section, referred to as Low Impact Development (LID) Criteria, must be met. For
the purposes of this Section, the LID methods and techniques described in Volume 3,
Chapter 1, Section 4.1, Runoff Reduction Practices, together with any methods or
techniques determined by the Utilities Executive Director to be functionally equivalent,
shall be considered LID techniques.
The LID Criteria are as follows:
(a) No less than seventy five percent (75%) of any newly developed or
redeveloped area, and any modification on a previously developed
area for which a construction permit is required under City codes
and regulations, must be treated using one or a combination of LID
techniques; or
(b) No less than fifty percent (50%) of any newly developed or
redeveloped area, and any modification on a previously developed
area for which a construction permit is required under City codes
and regulations, must be treated using one or a combination of LID
techniques, when a permeable pavement area covering at least
twenty five (25%) of the drivable surface area on private
development property is constructed as one of the components of
the LID treatment techniques used on that site.
(c) If, in the judgment of the Utilities Executive Director, one or more
requirements of this Section cannot be met due to site engineering
constraints, then a design alternative will be allowed, provided that
the design results in equal or better stormwater quality than would
compliance with the otherwise applicable requirement.
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Introduced, considered favorably on first reading, and ordered published this 5th day of
January, A.D. 2016, and to be presented for final passage on the 19th day of January, A.D. 2016.
__________________________________
Mayor
ATTEST:
_______________________________
City Clerk
Passed and adopted on final reading on the 19th day of January, A.D. 2016.
__________________________________
Mayor
ATTEST:
_______________________________
City Clerk