HomeMy WebLinkAboutCOUNCIL - AGENDA ITEM - 10/25/2011 - CACHE LA POUDRE RIVER FLOODPLAIN REGULATIONSDATE: October 25, 2011
STAFF: Jon Haukaas, Ken
Sampley, Marsha Hilmes-Robinson,
Brian Varella
Pre-taped staff presentation: available
at fcgov.com/clerk/agendas.php
WORK SESSION ITEM
FORT COLLINS CITY COUNCIL
SUBJECT FOR DISCUSSION
Cache La Poudre River Floodplain Regulations.
EXECUTIVE SUMMARY
A component of the Stormwater program review requested by City Council in October 2008
included a review of the level of regulation protecting life and property for areas within the Poudre
River floodplain. Floodplain regulation options have been presented and discussed at three (3)
Council work sessions. At the February 22, 2011 Work Session, Council expressed interest in
further investigation of the Adverse Impact Review (AIR) approach. Specific direction to staff was
to:
• Continue development of the AIR criteria, standards and review process with an expanded
Working Committee
• Perform additional public outreach
• Bring the item for Council review at a future date.
Based on further research, continued public outreach, and the results from a technical analysis
completed at the request of the Working Committee, staff is recommending a modified approach
that will incorporate key aspects of AIR with the current floodplain regulations. This approach
provides the benefit of addressing life safety and property damage considerations while avoiding
the cost and time impacts associated with requiring additional detailed floodplain analyses focused
on determining increases in flood elevations and velocities.
GENERAL DIRECTION SOUGHT AND SPECIFIC QUESTIONS TO BE ANSWERED
Given the importance of the Poudre River to the City of Fort Collins and its citizens:
1. Does City Council concur with the Staff recommendation that additional consideration be
given to implementing specific life safety and property damage criteria that will enhance and
support the existing floodplain regulations?
2. Upon review of the floodway surcharge analysis results, does City Council agree with the
elimination of the additional detailed engineering analyses, notification and mitigation
requirements originally proposed with the AIR approach?
October 25, 2011 Page 2
3. Is it acceptable to combine the additional Poudre River life safety and property damage
criteria along with mandated Colorado Water Conservation Board (CWCB) revisions to
Citywide floodplain regulations and present both for formal Council action in March 2012?
BACKGROUND / DISCUSSION
City Council requested a review of the Stormwater program in October 2008. Staff identified a list
of issues to be addressed that included a review of the level of regulation protecting life and property
for areas within the Poudre River floodplain. It is the City’s duty and responsibility to manage
foreseeable risks to protect current and future citizens from physical, financial, and emotional
impacts of flooding
Elements and Purpose of Floodplain Administration
The elements of floodplain administration consist of:
• Protect life-safety and property from the effects of flooding through proactive regulation,
emergency response and long-term planning
• Encourage sustainable construction practices that reduce burdens on future generations
• Reduce clean-up costs created by flood-damaged structures and property, minimizing the
volume of landfill wastes
• Reduce communitywide disruptions of commerce, livelihood and services.
Problem Statement
The Poudre River floods. Unless mitigated, development in the floodplain can result in adverse
flooding impacts. The current Poudre River Floodplain Regulations do not include requirements that
specifically address the following issues:
• Increased risk to human life and safety as a result of more people working within the 100-
year floodplain and increased risk to life and safety for emergency services workers and first
responders during flooding events.
• Impacts (as a result of increased flooding depths and velocities) of redirected flood waters
on adjacent, upstream and downstream properties within the existing 100-year floodplain
and properties that would be within an expanded 100-year floodplain resulting from new
development/redevelopment.
• Increased preservation of natural and beneficial functions of the floodplain including
minimized loss of riparian habitat, periodic “flushing” of sediment and debris to retain flood
conveyance and promote benthic species growth, provision of a buffer area for lateral
channel migration and increased natural water quality treatment, and groundwater recharge.
October 25, 2011 Page 3
The current regulations focus almost exclusively on protecting new structures from flooding
damage. Without additional requirements, the current 0.5 foot allowable floodway rise allows
potential adverse impacts to other property owners.
Adverse Impact Review
At the February 22, 2011 Council Work Session, staff was directed to pursue the Adverse Impact
Review (AIR) option as a possible revision to the Poudre River floodplain regulations. The current
regulations allow non-residential development within the 100-year flood fringe on the Poudre River
that meets specific criteria (i.e., freeboard, property use, etc.). Under these existing regulations, the
impacts caused by such development are not analyzed.
Staff developed the AIR option to permit non-residential development in the 100-year Poudre River
floodplain only if adverse impacts of the development on adjacent, downstream and/or upstream
properties can be either entirely avoided or adequately mitigated according to established criteria.
The criteria were developed with the goal of balancing the competing economic, environmental, and
public safety values of the Fort Collins community.
Working Committee
A citizen Working Committee of business and property owners, environmental stewards,
engineering professionals and interested parties was established initially in January 2011 to provide
feedback on the floodplain regulations to Council. The Working Committee met three times prior
to the February 22, 2011 Council Work Session. The Working Committee met three more times
over the summer and formed a Technical Subcommittee to develop data in response to concerns
regarding the magnitude of the issues identified in the problem statement.
The Working Committee requested that the Technical Subcommittee:
1. Analyze and provide specific information for key areas of the Poudre River to identify
properties and structures that could be subjected to increased flooding (i.e., velocities and
depths) from development and/or redevelopment within the Poudre River 100-year
Floodplain. This analysis is subsequently referred to as the “Floodway Surcharge
Analysis”; and,
2. Compare the existing regulations and proposed AIR process to evaluating its applicability
for evaluating life safety and property damage. This is subsequently referred to as the “Life
Safety / Damage Reduction / Property Rights Evaluation.”
Technical Advisory Committee
A Technical Advisory Committee (TAC) consisting of City staff from various departments and
divisions was established to provide input, feedback and guidance on the floodplain regulations and
the Adverse Impact Review approach. The TAC’s role was to evaluate the regulations and AIR
approach based on their respective professional expertise and department vision and mission while
utilizing a triple bottom line (TBL) philosophy that includes economic, social and environmental
considerations.
October 25, 2011 Page 4
Stormwater staff presented the results of the analysis completed by the Technical Subcommittee and
facilitated a discussion of the results to obtain TAC input and feedback on the floodplain regulations
and AIR process.
Adverse Impact Review -- Evaluation of Approach
The AIR approach and potential implementation was evaluated through the combination of a
Floodway Surcharge Analysis and Life Safety / Damage Reduction / Property Rights Evaluation.
Floodway Surcharge Analysis
Goal: Identify flooding impacts that allowable (under current regulations) development
will have on life safety and existing properties and structures along the Poudre River
from just above College Avenue downstream to Timberline Road and determine if
these impacts are of the magnitude and significance to support migrating to an
adverse impact review approach for floodplain management.
Approach: Quantify the potential impacts of the allowable rise (floodway surcharge) associated
with the current effective 100-Year ½-ft floodway model.
Results: Attachments 1 through 3 to this memo provide maps that illustrate the increase in
flood elevation and corresponding expansion of the 100-Year floodplain associated
with the maximum allowable rise under the current floodplain regulations. Key results
of impact to other properties as a result of filling in the flood fringe include:
• Loss of the flood fringe due to the placement of fill will result in an increase in
flow velocity during flooding conditions. However, these increases are not likely
to cause significant erosion or sediment transport beyond the existing 100-yr
flooding conditions;
• Changes in floodplain width were generally negligible with the exception of the
Link N Greens and North College areas. The Poudre River basin is largely
confined by the natural bluff on the Old Town Side (right bank, near Riverside),
and by man-made features on the left bank (Mulberry Street, Lemay Avenue);
• The Allowable Rise resulting from filling the floodplain is typically less than the
maximum permissible 0.5 ft throughout much of the reach of Poudre River basin
studied. The greatest potential increase in floodplain rise was near College
Avenue;
• Five (5) existing structures were identified that would be impacted and subjected
to a 100-Year flood event as result of filling in the flood fringe. Impacts include:
N Potential increase in damages
N Flood insurance will be mandatory if there are loans on the properties
N Properties will be subject to the City Code Chapter 10 floodplain
regulations.
October 25, 2011 Page 5
• One hundred and twenty-two (122) existing structures in the Poudre River
floodplain will potentially be subject to higher flood elevations ranging from 1/2-
inch to 6-inch plus the increased velocities associated with this flow;
• The College Avenue crossing area has the greatest potential risk due to increased
roadway overtopping. The surcharge may increase the flood elevation by an
additional 6 inches across College Avenue (from 18 inches to 24 inches);
significantly increasing the life-safety risk to the traveling public;
• The bridge for North College Avenue across the Poudre River has a moderate
increase in risk due to pressure flow on the bridge face, increasing bridge
washout scour potential, and a greater impact on the structure from debris; and
• Lemay Avenue has moderate risk of overtopping and flooding the Mulberry /
Lemay intersection and areas near the Home Depot and Walmart since the flood
elevation is 0.5 ft below the lowest overtopping elevation of the roadway, and
allowable rises would reduce this overtopping to within 0.2 ft of the lowest point
of the roadway.
Life Safety / Damage Reduction / Property Rights Evaluation
Goal: The over-riding purpose of floodplain regulations is to protect life-safety. If additional
people are working and acquiring services in the floodplain, there is a corresponding
increase in potential evacuation and rescue. This not only places the employees and
customers at risk but also the emergency response personnel performing rescue
operations. Protection of property is an issue not only for the new properties being
proposed to be built, but for existing properties. Debris generated by structures being
damaged or floatable materials being swept off-site can cause increased damage to
downstream properties and often cause debris blockages at bridges. The goal of this
analysis is to compare the existing regulations and proposed AIR Review process to
evaluate their applicability for addressing life safety and property damage.
Approach: Develop a matrix to provide a qualitative assessment of how the current regulations
and AIR process compare with respect to key considerations
Results: Attachment 4 to this memo illustrates the matrix created to assess how the current
regulations and AIR process compare in addressing life safety, property damage
reduction, and property rights issues. The matrix shows that the current regulations
either did not consider, or only minimally considered the following criteria:
• Risk to workers, customers, delivery people, etc. during a 100-year flood event
• Safe access for emergency personnel during an event
• Emergency warning and evacuation plans
• Blockage of existing bridge, culvert and stream improvements
• Notification to impacted property owners.
The matrix shows that the current regulations do consider, to a significant degree, the following
criteria:
October 25, 2011 Page 6
• Flood damage resistant materials
• Structure design for new development in the floodplain
• Freeboard.
Attachment 5 provides a tabular listing and comparison of the criteria originally proposed for
evaluation in conjunction with the AIR process and those proposed with a modified approach that
combines the current floodplain regulations with specific key life safety and property damage
considerations. Staff believes it is appropriate to incorporate the consideration of life safety and
property damage criteria into the regulations in conjunction with the upcoming process to adopt
revisions to the floodplain regulations based on the Colorado Water Conservation Board (CWCB)
approved Floodplain Rules and Regulations for the State of Colorado. Those revisions have not yet
been brought forth to prevent confusion with the Poudre River floodplain regulations discussion.
Background on these necessary revisions is included as Attachment 6.
STAFF RECOMMENDATION
Based on the results from the technical analyses, staff concluded that a comprehensive AIR review
process that requires a detailed engineering analysis of changes in flood elevations and velocities
and their impact on adjacent properties is not appropriate for all development situations in the
Poudre River floodplain. It is therefore the recommendation of staff that additional consideration
be given to implementing specific life safety and property damage criteria that will enhance and
support the existing floodplain regulations. These criteria should be presented in combination with
the mandated Colorado Water Conservation Board (CWCB) revisions to Citywide floodplain
regulations for formal Council action in March 2012.
Staff will partner with the Poudre Fire Authority to research and develop specific life safety and
property damage criteria that would enhance and support the current regulations, focusing on:
• Emergency Access and risk to new persons in the floodplain
• Emergency evacuation and warning plans
• Blockages and Damming.
PUBLIC OUTREACH
Feedback from both the citizen Working Committee and TAC support the recommendation of staff
that there are opportunities in the future to improve specific life-safety standards as a valuable
complement to the current regulations. This approach is also supported by the Office of Emergency
Management of the Poudre Fire Authority. Support was voiced for the need to prepare proactive
safety management and emergency warning plans that address escape routes for employees and/or
customers and also for developing criteria to require access routes for emergency workers. Perhaps
“dryland access” requirements could be modified to allow safe but “wet” access through areas
without significant flow (backwater flooding areas).
BOARD/COMMISSION RECOMMENDATIONS
The results of the Floodway Surcharge Analysis and Life Safety / Damage Reduction / Property
Rights Evaluation, feedback from the Working Committee and Technical Advisory Committee, and
the staff recommendation to pursue a modified approach consisting of the existing Poudre River
October 25, 2011 Page 7
Floodplain Regulations in combination with specific life-safety and property damage reduction
criteria were presented to both the Water Board (September 15, 2011) and Natural Resources
Advisory Board (September 21, 2011).
Water Board
Staff presented the information and responded to questions from the Board. Due to the complexity
of the subject matter, a significant amount of time was spent re-visiting floodplain concepts. Staff
also summarized the existing requirements outlined in the currently-adopted Poudre Floodplain
Regulations. There was extensive discussion of the technical analyses prepared in conjunction with
the Working Committee effort. The Board noted the importance of life safety and property damage
reduction as guiding floodplain management principles. Concern was expressed, however, that
more emphasis should be placed on environmental considerations. The Board then discussed
whether this emphasis should be included as a requirement in the Floodplain Management or Land
Use sections of City Code. Attachment 7 contains an excerpt of the minutes from the September
15, 2011 Water Board meeting. The Water Board recommendation includes language stressing the
need to increase preservation of natural and beneficial functions of the Poudre River floodplain as
shown below:
“The Water Board recommends the existing floodplain regulations be retained, but
that additional consideration to implementing specific life safety and property
damage criteria and increased preservation of natural and beneficial functions of the
floodplain that would enhance and support the current regulations be incorporated
with the process to adopt the new Floodplain Rules and Regulations for the State of
Colorado as approved by the Colorado Water Conservation Board (CWCB).”
Natural Resources Advisory Board (NRAB)
Staff presented the information and responded to questions from the Board. Based on questions
received at the Water Board regarding floodplain concepts, staff spent additional time reviewing and
explaining floodplain concepts and the existing requirements outlined in the currently-adopted
Poudre Floodplain Regulations. The technical analyses prepared in conjunction with the Working
Committee effort were discussed in detail. Similar to the Water Board discussion, the NRAB Board
noted the importance of life safety and property damage reduction as guiding floodplain
management principles. The Board reviewed and discussed the previous NRAB recommendation,
which indicated a preference for Option #2 (Revise the floodplain regulations to not allow any new
structures in the 100-Year floodplain). The Board expressed strong concern that development of
property within the Poudre River floodplain will adversely affect the natural and beneficial functions
of the River. There was concern that the economic benefits of this development will have negative
long term financial impacts on the City if the Poudre River is not protected and preserved. After
considerable discussion, the Board felt that its original recommendation was still applicable.
Attachment 8 contains the NRAB formal recommendation which is summarized below:
“The NRAB understands economic growth is important to the City of Fort Collins
but considers the health of the Poudre river also an important economic factor to the
City. The NRAB previously recommended Option #2 to Council in December, 2010
that new structures not be allowed in the Poudre River floodplain. This motion
reinforces the NRAB’s previous recommendation that Option #2 is still the best
October 25, 2011 Page 8
option from the Natural Resources perspective in order to protect the river and help
achieve the goals of the triple bottom line.”
ATTACHMENTS
1. Poudre River Floodway Surcharge Analysis – Overall Map
2. Poudre River Floodway Surcharge Analysis – Upstream and Downstream of College Avenue
3. Poudre River Floodway Surcharge Analysis – Linden Street to D/S (East) of Lemay Avenue
4. Life-Safety / Damage Reduction / Property Rights Evaluation
5. Criteria Comparison – AIR and Modified Approach
6. Colorado Water Conservation Board Revised Floodplain Rules and Regulations Background
7. Excerpt from draft Water Board Minutes, September 15, 2011 (Floodplain Regulations)
8. NRAB Formal Recommendation (Poudre River Floodplain Regulations)
9. Powerpoint presentation
10. Work Session Summary, February 22, 2011
11. Work Session Summary, January 11, 2011
12. Work Session Summary, August 24, 2010
13. Work Session Summary, December 8, 2009
Floodway Surcharge Analysis – Overall Map
Floodway Surcharge Analysis – North College
Floodway Surcharge Analysis – Link-N-Greens
Poudre River Floodplain Regulations
9/7/2011
Evaluation of Life-Safety, Damage Reduction,
and Neighboring Property Rights Protection Criteria
** Note – This does not include the technical criteria (depth and velocity) being evaluated
through additional quantitative analyses.
Scale: 0 (Not Considered) – 10 (Fully Considered)
Criteria Current Regulations Proposed AIR
Regulations
Risk to New Persons
Occupying the Floodplain
4
Current regulations
prohibit critical facilities
and new residential
structures.
7
Risk to workers and
customers of non-
residential structures.
Risk to Emergency
responders. Risk may be
mitigated by other criteria
such as dryland access,
emergency evacuation
plans, etc.
Dryland Access
0 8-10
Life-Safety Criteria
Emergency Warning and
Evacuation Plans
1-2
Currently considered
when floodproofing a
building.
6-7
Potential Debris
6
Current floatable
materials regulation.
7-8
Proposed regulation
would also address
fences, building being
damaged and generating
debris, etc.
Life-Safety and Flood
Damage Reduction
Criteria
Blockages and Damming
(Proposed fences, walls, rows of
trees, etc. Existing unmapped risk
upstream of bridges, railroad
crossings, etc.)
1 4-5
Flood Damage Resistant
Materials
6 7-8
Structure Design
4-5 7-8
Poudre River Floodplain Regulations
9/7/2011
Analysis of Impact on Other
Properties.
2
Analysis required if
doing a LOMR.
8
Mitigation of Impact on
Other Properties
1
Mitigation only required
if working in the
floodway and mitigation
only related to change in
flood elevation.
8
Public Notification
1
Minimal notification as
part of LOMR.
9-10
Neighboring Property Rights
Protection
Public Comment
3
Can comment through
P&Z for large projects.
9
Summary
Criteria Current Regulations Proposed AIR
Regulations
Life-Safety Criteria
2-3 7
Damage Reduction
Criteria
7 8
Neighboring Property
Rights Protection
1-2 8-9
Page 2 of 2
Poudre River Floodplain Regulations
9/7/2011
COMPARISON
Adverse Impact Review (AIR) Approach
vs.
Modified Approach
(Combination of Current Regulations plus
Life-Safety and Property Damage Considerations)
Criteria AIR Approach Modified Approach
Risk to New Persons
Occupying the Floodplain
X X
Emergency Access
X X
Life-Safety
Criteria
Emergency Warning and
Evacuation Plans
X X
Increase in Flood Elevation X
Increase in Velocity X
Increase in Erosion Potential X
Debris Potential X
Blockages and Damming
(Proposed fences, walls, rows of
trees, etc. Existing unmapped
risk upstream of bridges, railroad
crossings, etc.)
X X
Life-Safety and Flood
Damage Reduction Criteria
Structure Design
X X
Flood Damage
Reduction
Criteria
Flood Damage
Resistant Materials
X X
Analysis of Impact on Other
Properties.
X
Mitigation of Impact on Other
Properties
X
Neighboring
Property Rights
Protection
Public Notification
X
Poudre River Floodplain Regulations
9/7/2011
Revisions to City of Fort Collins Floodplain Regulations
(CWCB Rulemaking in November, 2010)
BACKGROUND
In November 2010, the Colorado Water Conservation Board (CWCB) approved the adoption and
implementation of new Floodplain Rules and Regulations for the State of Colorado.
Governmental entities are required to adopt floodplain regulations that meet or exceed those
established by the CWCB on or before January 14, 2014. While a majority of the floodplain
regulations currently in force within the City of Fort Collins meet or exceed the new
requirements, there are modifications that must be made to the existing regulations to be in
compliance, including but not limited to the following:
• A minimum of one foot of freeboard above the 100-Year Base Flood Elevation will
be required for the lowest floor elevation of residential and non-residential structures;
• Elimination of waiver to allow development within floodplains where City
improvements have resulted in floodplain modifications that have not yet been re-
mapped;
• All costs (including those for building floors above the first floor) must be included in
determining and applying rules with respect to substantial improvement for
development in all floodplains; and
• Enforcement of the City moderate-risk floodplain as currently designated.
These changes have not been included to date in the discussion regarding potential revisions to
the Poudre River floodplain regulations for the following reasons:
• They apply to all floodplains within the City and are not specific to the Poudre
River;
• They are not directly related to the implementation of an AIR approach to the Poudre
River; and
• There has been no public outreach to inform the community about the new
requirements.
Excerpt from Unapproved Water Board Minutes, September 15, 2011
Poudre River Floodplain Regulations
(Attachments available upon request).
Stormwater and Floodplain Program Manager Ken Sampley presented information on this item
and stated this item will also be presented to the Natural Resources Advisory Board. Ms. Hilmes-
Robinson was also available to answer questions concerning the regulations. Mr. Sampley
presented background information on the Poudre River as a flood threat. Since it is the largest
watershed in the city, the flood risk is greater because of rain, snow melt, and rain-on-snow
storm events.
Purpose of Poudre River Floodplain Regulations Review
This is one aspect of the stormwater repurposing effort. It is the City’s duty and responsibility to
manage foreseeable risks to protect current and future citizens from the impacts of flooding.
Problem Statement Summarized
Unless mitigated, development in the floodplain can result in adverse flooding impacts. The
current regulations do not include requirements that specifically address increased risk to human
life and safety, impacts of redirected flood waters, and increased preservation of natural and
beneficial functions of the floodplain. The current regulations focus primarily on protecting new
structures from flooding damage.
Floodplain Regulation Options
Mr. Sampley listed the four options for the board to consider.
Board discussion:
Can you remind us what the board initially recommended? The board recommended staff look
at Option #2 which states, the Poudre River floodplain regulations be revised to not allow any
new structures in the 100-year floodplain. This recommendation was made in 2010.
Did the Adverse Impact Review (AIR) involve the change in velocity? The AIR involved no
change in velocity or erosion.
Mr. Sampley stated this item was presented at the February 22, 2011 Council Work Session.
Council expressed interest in further investigation of the AIR approach with an expanded
Working Committee. The Working Committee consisted of property and business owners,
engineers, developers, environmental stewards, and staff. Staff developed the potential AIR
Review Criteria and Review Process with input from the Working Committee.
Several of the committee members questioned the Problem Statement. A technical subcommittee
was established as a result of this. This subcommittee looked at a floodway surcharge analysis as
well as life safety, damage reduction, and property rights evaluation criteria. The subcommittee
utilized City staff to provide input, feedback, and guidance on the floodplain regulations and the
AIR from a multi-disciplinary perspective. Utilities also evaluated this based on the Triple
Bottom Line (TBL) philosophy which includes economic, social, and environmental
considerations.
Mr. Sampley explained the model for the Floodway Surcharge Analysis. The goal of this model
is to identify flooding impacts that allowable developments will have on life safety and
determine if these impacts are of the magnitude and significance to support migrating to an AIR
approach for floodplain management. The model shows a maximum 6 inch floodway rise;
however, not all the cross sections are at 6 inches.
Board discussion:
What are the assumptions with the model? Are you assuming that every piece of land in the flood
fringe is developed and filled in? To develop the original floodway limits, the water surface
elevation is raised six inches. However, in this model, the surcharges from a Federal Emergency
Management Agency (FEMA) model were plugged into the cross section.
Is a portion of the flood fringe filled? The purpose of the surcharge model was to determine
impacts of the water surface elevation increases. This will make the floodway expand wider.
This model assumes no changes to the floodplain from stormwater mediation projects? There is
no capital projects proposed in this region. When the floodplain widens, there is an opportunity
to impact other properties that are not currently in the floodplain.
A board member asked for clarification on the cross section with the 3.8 inch rise versus the 5.5
inch rise. Ms. Hilmes-Robinson stated the model can be changed. The maximum is a six inch
rise, but each time the model is changed, the numbers will vary some.
The current regulations allow a 6 inch rise. What is allowable for the developer? A developer
does not have to conduct an analysis for building outside the floodplain or the floodway. Ms.
Hilmes-Robinson stated the purpose of the model is to predetermine what could happen with
developments. Mr. Sampley stated this is a very preliminary look.
A board member asked for clarification on topology changes concerning the rise. The maximum
is six inches.
A board member asked for clarification on whether fill was used on the property where the
Northside Aztlan Community Center was constructed. Ms. Hilmes-Robinson stated this structure
was not constructed on fill.
A board member asked for clarification if a new development with a six inch rise caused an
eleven inch rise at a different point along the floodway. Mr. Sampley stated that because of the
topology, the development would not cause a six inch rise.
If someone downstream builds a development, do they not have to cause a six inch rise? If a
developer builds outside the floodway, they do not have to quantify the impact.
A board member asked for clarification on what would happen if new developments were
constructed in the floodway. Ms. Holmes-Robinson drew a diagram explaining what would
happen if new developments were constructed in the referenced area.
Mr. Sampley gave a summary of the floodway surcharge analysis:
• Area added to the 100 year floodplain:
Total = 8.88 acres
Link-N-Greens only = 7.08 acres
• Number of structures not currently in the 100 year floodplain that would be subject to the
expanded (wider and deeper) 100-year floodplain = 5
• Number of structures currently in the 100-year floodplain that would experience an
increase in water surface elevation = 122 (up to six inches)
Board discussion:
Does that increase flood insurance? No, because most of the 122 buildings are older structures.
Future developments would need to look at elevating the structures to remove them from the
floodplain.
A board member expressed concern about the older buildings and feels these structures are just
as important as newer structures. Mr. Holmes-Robinson stated that the statement concerning the
older buildings came from the working committee and property owners. There are some
residential structures; however, most of the structures are commercial.
A board member asked for clarification on velocity in the area. Ms. Holmes-Robinson explained
the Product Corridor Equation (depth times velocity greater than or equal to 6).
The current regulations allow 18 inches of water? No, that is the existing condition. Currently,
the water overtops College Avenue and Vine Drive without any further developments.
Are you assuming the current rainfall criteria? The Poudre River does not use rainfall criteria in
the mapping.
Mr. Sampley gave a summary of the life safety, damage reduction, and property rights evaluation
criteria. This was a separate process in addition to the technical analysis. The goal is to compare
the existing regulations and proposed AIR review process to evaluating their applicability for
evaluating life safety and property damage.
Board discussion:
A board member asked for clarification concerning if someone wants to develop in the area,
whether they have to conduct an analysis of the floodplain? No, they are not required to do an
analysis if they are in the flood fringe. Mr. Haukaas stated by identifying the floodway and flood
fringe, the analysis has already been conducted.
Mr. Sampley gave a summary of the results. The matrix shows the current regulations either did
not consider, or only minimally considered the following criteria:
• Risk to workers, customers, delivery people, etc. during a 100-year flood event;
• Safe access for emergency personnel during an event;
• Emergency warning and evacuation plans;
• Blockage of existing bridge, culvert, and stream improvements; and
• Notification to potentially impacted property owners
The matrix shows that the current regulations do consider, to a significant degree, the following
criteria:
• Flood damage resistant materials
• Structure design for new development in the floodplain
• Freeboard
Mr. Sampley gave a summary of the recommendations from the working committee. Staff
considered the possibility of requiring if a new development should conduct a technical
engineering analysis to determine the increase in velocity. Since part of the impact has already
been indentified, it does not seem appropriate for an additional analysis to be conducted;
however, when an analysis is not conducted, the opportunity is lost to provide notice to some of
the properties. Staff believes emergency access and emergency evacuation and warning plans
should be reviewed to improve the current regulations. During the process, staff also
incorporated technical guidance such as ineffective flow and conveyance shadowing.
Mr. Sampley gave a summary of the recommendations from the technical advisory committee.
Staff met separately with the Poudre Fire Authority (PFA). They are very interested in regards to
implementing specific life safety and property damage criteria. They also desire to focus and
improve coordination of City departments to better consider life safety and property damage
considerations including street layouts and zoning.
Mr. Sampley gave a summary of the revisions to the floodplain regulations. In November 2010,
the Colorado Water Conservation Board (CWCB) approved new floodplain rules and
regulations. In January 2014, local governments will be required to adopt floodplain regulations
that meet or exceed the new requirements.
Board discussion:
What is a moderate risk floodplain? In some instances, the 500-year floodplain is mapped; in
other instances, shallow flooding is mapped. This is not currently regulated. Some areas will now
be required to have a floodplain use permit.
Does the map show the 500-year floodplain? No, this map does not show the 500-year
floodplain. Mr. Haukaas stated today’s discussion does not have an impact on the 500-year
floodplain; however, these issues will be discussed with the board at a later time.
Mr. Sampley gave a summary of the conclusions. He stated it does not seem necessary to require
an additional engineering analysis to quantify the impacts; however, staff believes that specific
life safety and property damage criteria could be combined with current floodplain regulations to
enhance regulations.
Mr. Sampley gave a summary of staff’s recommendations, which include retaining existing
floodplain regulations, but also to consider implementing specific life safety and property
damage criteria that would enhance the current regulations. Recommendations also include
partnering with PFA to develop criteria concerning emergency access, evacuation, and
blockages. Staff also recommends incorporating the criteria into the regulations required by the
CWCB.
Board discussion:
You can fill in the entire flood fringe and it doesn’t raise the water level along the mapped
corridor more than 5.9 inches? Yes, that is correct.
What defines the floodway limits? The concept behind the floodway is to preserve an area with
the highest risks. This is based on the fact that historically, individuals and businesses like to
build near creeks and rivers.
Chairperson Janett stated she feels protection of the natural floodplain as well as the
environmental component (as part of the TBL analysis) has not been taken into consideration.
Mr. Sampley stated development cannot happen in the floodway without a Conditional Letter of
Map Revision (CLOMR) or Letter of Map Revision (LOMR).
If you are filling in the floodplain, you are increasing the speed of the water. The water will be
channeled instead of going through a wide area. How can we develop the flood fringe exercise?
Mr. Haukaas stated when Utilities started looking at the AIR process, Utilities looked at a worst
case scenario. The area is still going to flood, but the overbank has some advantages. The impact
of a worst case scenario is pretty minimal. There are commonalities from the AIR process,
including increased evacuation, better dry land access, and public safety components.
Does the City plan to enhance and maintain the models over time? Are you proactively looking
at properties where development could occur with potential safety issues? Is the City going to
plan out recommendations if a development does occur? Yes, Utilities will continually try to
improve the mapping. The federal grant process will re-map the area to obtain better data. Until
the development happens, Utilities does not know specifically on the map where they will be
located.
Is it possible to address the flood fringe in the same way as a landscape requirement? This
analysis does not take the Poudre River buffer into account. Ms. Hilmes-Robinson stated the
Poudre River buffer is a natural areas buffer. The area defined as a buffer depends on important
features in the area, such as an eagle’s nest or wetlands. In some places the areas are wider than
the floodway. In other places they are within the floodway.
Is the Link-N-Greens property outside the buffer zone? Yes.
Could the buffer be within the floodway? Yes, in certain places.
What is the current regulation for the floodway? The current regulation is for a 6-inch floodway.
This matches the current Larimer County regulation.
Ms. Hilmes-Robinson stated there is a whole series of criteria relating to the structure. Most of
the criteria are related to property protection of the structures. This is because floodplain
regulations were originally developed for the purpose of reducing payouts from flood insurance.
No residential structures or critical facilities are allowed in the 100-year floodplain.
Will you change the floodway and floodplain limits when you re-map? Would property be
grandfathered in? No, property in the floodplain would not be grandfathered in. It would be
subject to the new floodway requirements.
How much did the modeling cost? The modeling cost approximately $7,000-8,000.
A board member questioned the statement from the problem statement concerning increased
preservation of natural and beneficial functions of the floodplain. Mr. Sampley stated this is
covered by the requirements in the City Code concerning the natural areas buffer; however, it is
not indentified in the floodplain portion of the Code.
The board member suggested this should not be part of the problem statement.
Chairperson Janett stated that more floodplain regulations will be presented to the board at
later times. The City had a 0.1 rise on the books for eight years, from 2000 to 2008, and chose to
relax their standard in 2008. The board may choose the option for a lesser rise in the future.
Also, the board is scheduled to hear an item on the state’s modeling for Climate Change. Due to
the potential for greater flooding frequency and higher magnitude storms, today’s 100-year
flood fringe may not be the same as what it will be 30 years in the future.
Mr. Sampley reiterated the staff recommendation which states the existing floodplain regulations
be retained, but that additional consideration be given to implementing specific criteria, which
are similar to the AIR criteria. This would be a modified approach.
Board discussion:
A board member stated the recommendation does not consider the environmental aspect in the
regulations. Chairperson Janett stated the motion wording can be modified to include a
statement for the environmental aspect.
What is wrong with cross referencing the flood regulations with some of the environmental
regulations in the City Code? Perhaps a gap analysis can be done concerning this. Mr. Sampley
requested Deputy City Attorney Carrie Daggett respond to this question. Ms. Daggett stated the
Land Use Code requirements contain information that applies to development activities. The
Land Use Code contains a definition of development; however, there is a broader definition of
development in Chapter 10 of the City Code. In relating to floodplain management and effects on
flood flows, there legally would be room to have requirements in Chapter 10. She stressed it is
important to think about the relationship in terms of the floodplain provisions. Ms. Hilmes-
Robinson stated the code language is not void of any code that talks about velocity and erosion
issues. The Land Use Code and Chapter 10 include provisions concerning this.
Board Member Brunswig requested a friendly amendment to staff’s recommended motion.
The motion did not carry.
Discussion on the motion:
Chairperson Janett asked for clarification on what Board Member Brunswig means by “not be
retained.” Board Member Brunswig stated that she wants the environmental aspect to be
considered since the other aspects are being considered.
Board Member Goldbach requested a friendly amendment to the motion. She suggested building
the motion around the fact that the AIR might not be worth the expense.
The motion was not seconded. The motion does not carry.
Mr. Sampley stated the AIR approach as originally proposed included all of the considerations
identified in Attachments 5 and 6 to the Poudre River Floodplain Regulations AIS as well as the
determination of impacts to base flood elevations, velocities, and erosion potential. However,
based on the results from the Floodway Surcharge Analysis, a comprehensive AIR review
process that requires a detailed engineering analysis of changes in flood elevations and velocities
and their impact on adjacent properties is not appropriate for all development situations in the
Poudre River floodplain. Staff believes that incorporating specific life safety and property
damage reduction criteria in combination with the existing floodplain regulations will address the
key common considerations associated with public safety.
Board Member Brown requested a friendly amendment to staff’s recommended motion. He liked
the motion language, but would like to modify it slightly to include the environmental
consideration. He would like the floodplain to function in its natural capacity.
Amended Motion: Board Member Brunswig moved that the Water Board recommend that
the existing floodplain regulations not be retained until Council considers environmental
aspects of the Triple Bottom Line analysis of the Poudre River regulations and include
protection of the natural processes of the floodplain.
Board discussion:
A board member feels it would be valuable to hear comments from members of the Natural
Resources Advisory Board after the item is presented to them.
Ms. Hilmes-Robinson asked the board if there are specific criteria they are looking at that might
help guide staff in the right direction.
A board member stated the new AIR process seemed to focus on processes to protect structures.
He is interested in the methods available to address the beneficial aspects of the floodway for
presentation to the board.
Chairperson Janett stated the working committee was predominantly composed of business
developers and real estate individuals. She feels there is plenty of expertise available on the
subject for future discussion.
Vote on the motion: It passed unanimously.
Amended Motion: Board Member Brown move the Water Board recommend the existing
floodplain regulations be retained, but that additional consideration to implementing
specific life safety and property damage criteria and increased preservation of natural and
beneficial functions of the floodplain that would enhance and support the current
regulations be incorporated with the process to adopt the new Floodplain Rules and
Regulations for the State of Colorado as approved by the Colorado Water Conservation
Board (CWCB). Board Member Gessler seconded the motion.
Natural Resources
215 N. Mason
PO Box 580
Fort Collins, CO 80522
970.221-6600
970.224-6177 - fax
fcgov.com
MEMORANDUM
FROM THE CITY OF FORT COLLINS
NATURAL RESOURCES ADVISORY BAORD
Date: October 6, 2011
To: Mayor and Council Members
From: Liz Pruessner on behalf of the Natural Resources Advisory Board
Subject: Poudre River Floodplain Regulations
The NRAB considered all the new information on the floodplain regulations presented at our meeting on
September 21, 2011. The City was correct in the decision to develop more information by initiating the
Citizen Working Committee and the Technical Advisory Committee to analyze existing floodplain
regulations and conduct the Adverse Impact Review. The committees were also asked to consider the
Triple Bottom Line in their analysis. This is a complex issue and the new information that was gained in
the process proved most beneficial. Development in the floodplain can cause adverse impacts and this
process revealed deficiencies that our existing floodplain regulations do not address including:
o Increased risk to human life and safety (workers, customers, emergency responders, etc.);
o Impacts (as a result of increased flooding depths and velocities) of redirected flood
waters; and
o Increased preservation of natural and beneficial functions of the floodplain.
While the NRAB certainly supports the staff recommendation that additional consideration should be
given to implementing specific life safety and property damage criteria that would enhance and support
the current regulations, we feel the best way to accomplish the goals of protecting life, safety, property
and the health of the Poudre River is not to allow development to encroach into the floodplain. There are
threats to existing structures in the floodplain and it makes no sense to add to the risk by allowing more
structures to be built.
City Plan spells out principles designed to minimize the risk while supporting the long term health of the
river:
Principle ENV 26: The City will manage the Poudre River floodplain to minimize potentially
hazardous conditions while promoting natural processes associated with flooding, erosion and
channel migration to occur over time as appropriate.
Encroaching into the floodplain does not support the sustainability of the river or the community.
The NRAB feels that the staff recommendation does not focus enough attention on the environmental
considerations of the triple bottom line analysis. The NRAB understands the importance of economic
growth to the City of Fort Collins, but considers the health of the Poudre River also a vitally important
economic factor to the City. Maintaining a healthy flowing river is in the long term economic interests of
the City. Numerous studies have shown the value of the river, our Natural Areas and trails to the local
economy.
2
The NRAB previously recommended Option #2 to Council in December, 2010 that new structures not be
allowed in the Poudre River floodplain. This motion reinforces the NRAB’s previous recommendation
that:
Option #2: The Poudre River floodplain regulations be revised to not allow any new structures in
the 100-Year floodplain is still the best option from the Natural Resources perspective in order to
protect the river and help achieve the goals of the triple bottom line.
This vote was unanimous.
For reference, we enclose our motion from December 2010 with this memo.
Please feel free to contact me regarding the NRAB’s comments on this issue.
Respectfully Submitted,
Liz Pruessner, Chair
Natural Resources Advisory Board
cc: Darin Attebury, City Manager
John Stokes, Director, Natural Resources Dept.
Susie Gordon, Staff Liaison
1
Poudre River Floodplain Regulations
Potential Revisions
City Council Work Session
October 25, 2011
Jon Haukaas, P.E.
Water Engineering Field
Operations Manager
Brian Varrella, P.E., CFM
Floodplain Administrator
Ken Sampley, P.E.
Stormwater and Floodplain
Program Manager
Marsha Hilmes-Robinson, CFM
Floodplain Administrator
2
1. Does City Council concur with the Staff
recommendation that additional consideration
be given to implementing specific life safety
and property damage criteria that will enhance
and support the existing floodplain
regulations?
General Direction / Specific Questions
Page 1 of 22
3
2. Upon review of the floodway surcharge
analysis results, does City Council agree with
the elimination of the additional detailed
engineering analyses, notification and
mitigation requirements originally proposed
with the AIR approach?
General Direction / Specific Questions
4
3. Is it acceptable to combine the additional
Poudre River life safety and property damage
criteria along with mandated Colorado Water
Conservation Board (CWCB) revisions to City-
wide floodplain regulations and present both
for formal Council action in March 2012?
General Direction / Specific Questions
Page 2 of 22
5
The Poudre River is a Flood Threat
Poudre is the largest
watershed in the city
– Drains 1,537 square
miles of land into Fort
Collins
– Generates a peak flow
of 13,300 cfs and
velocities over 13 fps
– Can flood for days or
weeks vs. hours in
other basins
– Floods can be caused
by rain, snowmelt, and
rain-on-snow storm
1904 Poudre River flood. High water events
mark on homes in Andersonville.
6
Purpose of Poudre River
FloodplainReview Floodplain Regulations Review
– Review of Floodplain Regulations is one aspect
of the Stormwater Repurposing effort.
– There is a flood risk on the Poudre River
• Existing properties in the Poudre floodplain are
already at risk
• The goal is to not increase this risk for the future
– It is the City’s duty and responsibility to manage
foreseeable risks to protect current and future
citizens from physical, financial, and emotional
impacts of flooding
Page 3 of 22
7
PROBLEM STATEMENT -- Summarized
The Poudre River floods. Unless mitigated, development
in the floodplain can result in adverse flooding impacts.
The current Poudre River Floodplain Regulations do not
include requirements that specifically address:
– Increased risk to human life and safety (workers,
customers, emergency responders, etc.);
– Impacts (as a result of increased flooding depths and
velocities) of redirected flood waters; and
– Increased preservation of natural and beneficial functions
of the floodplain.
The current regulations focus almost exclusively on
protecting new structures from flooding damage.
Poudre River Floodplain Regulations
8
Option #1: The Poudre River floodplain regulations
be revised to adopt a 0.1 foot rise floodway; OR
Option #2: The Poudre River floodplain regulations
be revised to not allow any new structures in the
100-Year floodplain; OR
Option #3: No change to the Poudre River floodplain
regulations (null alternative); OR
Option #4: Allow all non-residential development that
meets proposed Adverse Impact Review (AIR)
Criteria
Floodplain Regulation Options
Page 4 of 22
9
Feb 22 2011 Council Work Session
Council expressed interest in further
investigation of the AIR approach
Specific direction to Staff:
– Continue development of the AIR criteria, standards
and review process with an expanded Working
Committee;
– Perform additional public outreach; and,
– Bring the item for Council review at a future
(TBD) Council Work
Poudre River Floodplain Regulations
10
Working Committee (Citizens)
• Established in January 2011. Three (3) meetings
prior to Feb 22, 2011 Council Work Session
• Property/business owners, engineers,
developers, environmental stewards, FCU Staff
• Staff developed potential AIR Review Criteria
and Review Process with input from Working
Committee (Presented on Feb. 22, 2011)
• Committee members expressed concerns with
AIR Criteria and Review Process
Poudre River Floodplain Regulations
Page 5 of 22
11
Working Committee (Citizens)
• Meetings on June 13, 2011
July 11, 2011
August 22, 2011
• Committee Members questioned the
Problem Statement
• Established a technical subcommittee
– Floodway surcharge analysis
– Life Safety / Damage Reduction / Property
Rights Evaluation Criteria
Poudre River Floodplain Regulations
12
Technical Advisory Committee
• Utilize City staff to provide input, feedback
and guidance on the floodplain regulations
and the Adverse Impact Review from a multi-
disciplinary perspective.
Poudre Fire Authority Economic Dev Police
Advance Planning Natural Areas Engineering
Development Review Parks and Rec
• Evaluate based on a triple bottom line (TBL)
philosophy that includes economic, social
and environmental considerations.
Poudre River Floodplain Regulations
Page 6 of 22
13
Floodway Surcharge Analysis
GOAL
Identify flooding impacts that allowable (under current
regulations) development will have on life safety and
existing properties and structures along the Poudre
River and determine if these impacts are of the
magnitude and significance to support migrating to an
adverse impact review approach for floodplain
management.
APPROACH
Quantify the potential impacts of the allowable rise
(floodway surcharge) associated with the current
effective 100-Year ½-ft floodway model.
Poudre River Floodplain Regulations
14
0.5-ft Rise
Riparian Channel
Overbank
Riparian
Overbank
100-year Floodplain
Definitions – Floodplain and Floodway
Natural River at 1% Annual Chance Flood Stage
Fill
Material Flood
Fringe
0.5-ft Rise Floodway Flood
Fringe
Fill Material
BFE
Floodplain Concepts
Page 7 of 22
15
• A 6-inch floodway designates an area of a river
where encroachment is allowed to cause a
maximum rise of up to 6-inches.
– Optimized does not mean rise of 6.0 inches
globally
– Optimization meets multiple goals and intents
(more later)
• Usually not obvious to the casual observer
• Not tied to physical features in the field
• Hydraulic modeling considerations may only allow
for rises less than 6 inches in certain locations.
Floodway Concept
16
• Objective: The river needs to be modeled as a
whole, not just one cross section at a time.
• Common reasons 6-inch rise is not achievable:
1. Adjacent cross sections increase > 6 inches
2. Line smoothing changes boundary location
3. Negative surcharges
4. Unequal conveyance
5. Engineering expertise + experience
Maximum 6-6 -inch Rise Challenges
Page 8 of 22
17
18
Line Smoothing
Page 9 of 22
19
Line Smoothing
Equal Conveyance Reduction Example
Page 10 of 22
Less Than 6-6 -inch Rise
22
• A floodway boundary is not a physical feature
• It is ultimately up to the engineer to balance all
challenges – using technical expertise
• Optimized does not mean rise of 6.0 inches all
the time
• There are an infinite number of potential
encroachments in a floodway analysis
Floodway Conclusions
Page 11 of 22
23
Poudre River Floodplain Regulations
Floodway Surcharge Analysis -- Results
AIS Attachment 1
24
Poudre River Floodplain Regulations
Floodway Surcharge Analysis -- Results
AIS Attachment 2
Page 12 of 22
25
Poudre River Floodplain Regulations
Floodway Surcharge Analysis -- Results
AIS Attachment 3
26
SUMMARY
• Area added to the 100-Year floodplain:
• Total = 8.88 acres
• Link N Greens only = 7.08 acres
• Number of structures not currently in the 100-Year
floodplain that would be subject to the expanded
(wider and deeper) 100-Year floodplain = 5
• Number of structures currently in the 100-Year
floodplain that would experience an increase in
water surface elevation (and corresponding depth
of flooding) = 122 (up to 6 inches)
Poudre River Floodplain Regulations
FloodwayAnalysis Floodway Surcharge Analysis
Page 13 of 22
27
Life Safety / Damage Reduction / Property
Rights Evaluation Criteria
GOAL
Compare the existing regulations and proposed AIR
Review process to evaluating their applicability for
evaluating life safety and property damage
APPROACH
Develop a matrix to provide a qualitative assessment of
how the current regulations and AIR process compare
with respect to key considerations
Poudre River Floodplain Regulations
Results
Poudre River Floodplain Regulations
Life Safety / Damage / Property Rights
Evaluation of Life-Safety, Damage Reduction,
and Neighboring Property Rights Protection Criteria
** Note – This does not include the technical criteria (depth and velocity) being evaluated
through additional quantitative analyses.
Scale: 0 (Not Considered) – 10 (Fully Considered)
Criteria Current
Regulations
Proposed AIR
Regulations
Risk to New Persons
Occupying the Floodplain
4
Current regulations
prohibit critical
facilities and new
residential structures.
7
Risk to workers and
customers of non-
residential structures.
Risk to Emergency
responders. Risk may
be mitigated by other
criteria such as dryland
access, emergency
evacuation plans, etc.
Dryland Access
0 8-10
Life-Safety Criteria
Emergency Warning and
Evacuation Plans
1-2
Currently considered
when floodproofing a
building.
6-7
Potential Debris
6
Current floatable
materials regulation.
7-8
Proposed regulation
would also address
fences, building being
damaged and
29
Results
The matrix shows that the current regulations
either did not consider, or only minimally
considered the following criteria:
– Risk to workers, customers, delivery people, etc.
during a 100-year flood event;
– Safe access for emergency personnel during an
event;
– Emergency warning and evacuation plans;
– Blockage of existing bridge, culvert and stream
improvements; and,
– Notification to potentially impacted property owners
Poudre River Floodplain Regulations
Life Safety / Damage / Property Rights
30
Results
The matrix shows that the current regulations
do consider, to a significant degree, the
following criteria:
• Flood damage resistant materials
• Structure design for new development in the
floodplain
• Freeboard
Poudre River Floodplain Regulations
Life Safety / Damage / Property Rights
Page 15 of 22
31
Recommendations of Working Committee
• Use modified approach that retains existing
floodplain regulations but considers incorporation
of key aspects of AIR criteria (See below)
• Additional consideration should be given in the
future to implementing specific life safety and
property damage criteria that would enhance and
support the current regulations (i.e.)
• Emergency Access and risk to new persons
in the floodplain
• Emergency evacuation and warning plans
• Blockages and damming
• Incorporate Technical Guidance (Ineffective flow
and Conveyance Shadowing) into floodplain
administration process
Poudre River Floodplain Regulations
32
Recommendations of TAC
• Retain existing floodplain regulations (floodway
surcharge technical analysis indicated full
implementation of AIR approach is not justified)
• Poudre Fire Authority – Strong support for
implementing specific life safety and property
damage criteria that would enhance and support
the current regulations:
• Emergency Access and risk to new persons
in the floodplain
• Emergency evacuation and warning plans
• Blockages and damming
• Debris reduction
Poudre River Floodplain Regulations
Page 16 of 22
33
Water Board Recommendation
• Importance of life safety and property damage reduction
• Concern -- Preservation of natural and beneficial functions
“The Water Board recommends the existing floodplain
regulations be retained, but that additional consideration
to implementing specific life safety and property damage
criteria and increased preservation of natural and
beneficial functions of the floodplain that would enhance
and support the current regulations be incorporated with
the process to adopt the new Floodplain Rules and
Regulations for the State of Colorado as approved by the
Colorado Water Conservation Board (CWCB).”
Poudre River Floodplain Regulations
AIS Attachment 7
34
NRAB Recommendation
• Option #2 -- Do not allow any new structures in floodplain
• Concern – Preservation of natural and beneficial functions
• Concern – Potential negative long term economic impacts
“The NRAB understands economic growth is important to
the City of Fort Collins but considers the health of the
Poudre river also an important economic factor to the City.
The NRAB previously recommended Option #2 to Council
in December, 2010 that new structures not be allowed in
the Poudre River floodplain. This motion reinforces the
NRAB’s previous recommendation that Option #2 is still
the best option from the Natural Resources perspective in
order to protect the river and help achieve the goals of the
triple bottom line.”.”
Poudre River Floodplain Regulations
AIS Attachment 8
Page 17 of 22
35
Revisions to Floodplain Regulations (CWCB)
• Nov. 2010 -- CWCB approved new Floodplain
Rules and Regulations for Colorado
• Jan. 2014 -- Local governments required to
adopt floodplain regulations that
meet or exceed new requirements
• Majority of current Fort Collins floodplain
regulations meet or exceed new requirements
Poudre River Floodplain Regulations
AIS Attachment 6
36
Revisions to Floodplain Regulations (CWCB)
• There are modifications needed to some
regulations, for example:
• One foot freeboard above 100-Year BFE
(currently 6 inches in some instances)
• Elimination of waiver -- Development in
floodplains where floodplain modifications
not yet mapped
• All costs must be included in determining
substantial improvement requirements
• Enforcement of moderate risk floodplain.
Poudre River Floodplain Regulations
Page 18 of 22
37
Revisions to Floodplain Regulations (CWCB)
• These changes have not been included to date in
the discussion regarding potential revisions to the
Poudre River floodplain regulations for the
following reasons:
• They apply to all floodplains within the City and are
not specific to the Poudre River;
• They are not directly related to the implementation of
an AIR approach to the Poudre River; and
• There has been no public outreach to inform and
obtain feedback on their incorporation.
Poudre River Floodplain Regulations
38
Conclusions
• Comprehensive AIR review process that
includes detailed engineering analyses of
changes in flood elevations and velocities and
their impact on adjacent properties is not
required
• Specific life-safety and property damage criteria
could be combined with current floodplain
regulations to enhance regulations
Poudre River Floodplain Regulations
Page 19 of 22
39
Staff Recommendation
• Additional consideration should be given to
implementing specific life safety and property
damage criteria that will enhance and support the
existing floodplain regulations. These criteria
should be presented in combination with the
State-mandated revisions to citywide floodplain
regulations for Council action in March, 2012.
• Partner with Poudre Fire Authority to develop
criteria with input from public outreach process
Poudre River Floodplain Regulations
Poudre River Floodplain Regulations
COMPARISON
Adverse Impact Review (AIR) Approach
vs.
Modified Approach
(Combination of Current Regulations plus
Life-Safety and Property Damage Considerations)
Criteria AIR Approach Modified Approach
Risk to New Persons
Occupying the Floodplain
X X
Emergency Access
X X
Life-Safety
Criteria
Emergency Warning and
Evacuation Plans
X X
Increase in Flood Elevation X
Increase in Velocity X
Increase in Erosion Potential X
Debris Potential X
Blockages and Damming
(Proposed fences, walls, rows of
trees, etc. Existing unmapped
risk upstream of bridges, railroad
crossings, etc.)
X X
Life-Safety and Flood
Damage Reduction Criteria
Structure Design
X X
Flood Damage
Reduction
Criteria
Flood Damage
Resistant Materials
X X
Analysis of Impact on Other
Properties.
X
Mitigation of Impact on Other
Properties
X
Neighboring
Property Rights
Protection
Public Notification
41
1. Does City Council concur with the Staff
recommendation that additional consideration
be given to implementing specific life safety
and property damage criteria that will enhance
and support the existing floodplain
regulations?
General Direction / Specific Questions
42
2. Upon review of the floodway surcharge
analysis results, does City Council agree with
the elimination of the additional detailed
engineering analyses, notification and
mitigation requirements originally proposed
with the AIR approach?
General Direction / Specific Questions
Page 21 of 22
43
3. Is it acceptable to combine the additional
Poudre River life safety and property damage
criteria along with mandated Colorado Water
Conservation Board (CWCB) revisions to City-
wide floodplain regulations and present both
for formal Council action in March 2012?
General Direction / Specific Questions
44
Poudre River Floodplain Regulations
Potential Revisions
QUESTIONS / FEEDBACK
Page 22 of 22
Page 1 of 2
Page 2 of 2
Page 1 of 2
Page 2 of 2
Utilities Executive Director
City of electric. stormwater. wastewater. water
Fort CoLLins 700 Wood St.
970.224.6003 TDD
utilities @fcgov.com
fcgov.com/utilities
MEMORANDUM
Date: August 26, 2010
To: Mayor Hutchinson and City Council members
Through: Darin Atteberry, City Manager
Brian Janonis, Utilities Executive Director
From: Jon Haukaas, Water Engineering and Field Services Manager
Reference: August 24, 2010 Work Session Summary — Floodplain Regulations
Jon Haukaas, Water Engineering and Field Services Manager and Marsha Hilmes-Robinson,
Floodplain Administrator, presented Council with a brief overview of the work done to date on
the Poudre Floodplain Regulations. Council members present included Mayor Doug
Hutchinson, Mayor Pro Tern Kelly Ohlson, Ben Manvel, David Roy, Wade Troxell, and Aislinn
Kottwitz.
Staff began with the interrelationship between this effort and Plan Fort Collins. It was
recognized that the Poudre River is key to the sustainability of Fort Collins. There was
discussion indicating that Plan Fort Collins is a long range vision while revisions to the Poudre
River Floodplain Regulations are immediate considerations.
The staff presentation reviewed the three options of proposed levels of floodplain regulation.
(1) Return to a 0.1 foot allowable floodway rise limitation, or (2) implement a restriction on new
and expanded structures within the floodplain, or (3) maintain the current regulations.
Next staff explained why this item was being discussed, mainly its relation to the Stormwater
Repurposing efforts and also its relevance to the Plan Fort Collins discussion. Information
regarding the number of parcels, acreage of parcels, and maps showing specific areas of concern
under the various options was discussed. A significant portion of the remaining discussion
included clarification of the concepts associated with floodplains and the effect of fill or other
forms of development.
Key discussion and feedback by Council:
I. Public Outreach Process to explain the range of options considered for proposed changes to
the Floodplain Regulations.
In general, the Council felt that a significant amount of outreach needed to happen and more
should have occurred prior to this discussion . Staff reiterated that the work session serves as
Page 1 of 2
Ft°oLLins
a process check before time and resources are utilized to move forward and that this work
session would serve as the beginning of a substantive outreach process.
Outreach efforts envisioned would include Boards and Commissions, City departments,
stakeholders (i.e. impacted property owners, business associations, interested citizens), and
the general public. Parcel-specific information is currently being developed to identify
impact to individual property owners as the next step.
2. Preference on Options for Regulating the Floodplain
Council did not feel they had sufficient public feedback to have a preferred option at this
time. They were also concerned about these regulations being applied only to the Poudre
River Floodplain. Council discussed the need to look for additional options beyond the three
currently under consideration, including those related to the “No Adverse Impact” approach
that is gaining support nationally.
Council expressed a range of comments and feedback. This included:
• The concern that the recommendations to strengthen the regulations were not justified
and that they would adversely affect the economic health and viability of Fort Collins.
The Downtown River District is a key area of development for the City and
coordinated development approach along the river would be the prudent approach.
• That there needs to be a balance between the economic, social and environmental
considerations for the river.
• Fort Collins needs to stop building where it is likely to flood. ‘Let the river he a
river.” In accordance with the City Plan, we are to protect and restore the natural
functions of the river.
• The “river is a workhorse,” and the community “should use it more as a playground,
not a plaything.”
• That ripwian edge development should be the exception, not the rule, and that 50 to
100 years from now a natural Poudre River would he the greatest community attribute
in Fort Collins.
3. Comments to be added to the Triple Bottom Line (TBL) Analysis Map
Time did not allow an in depth discussion of the TBL chart. One Council member did not
feel this chart format was easy to use and that it needs to be better organized. Staff
concluded with a brief explanation of how comments would be added to the Map.
Three Council members supported continuing the discussion while two felt the need was not
sufficiently expressed to warrant continuing the process.
Specific direction was also provided to Staff to he prepared to address the following questions:
I. What is the purpose and need to change the floodplain regulations?
2. Analyze the impact on properties in more detail.
3. Provide more economic analysis.
4. Describe better “Less people at risk” - how many?
5. Provide more information on “No Adverse Impact” to the public and to the Council.
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AIS Attachment 5
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generating debris, etc.
Life-Safety and Flood
Damage Reduction
Criteria
Blockages and Damming
(Proposed fences, walls, rows of
trees, etc. Existing unmapped
risk upstream of bridges,
railroad crossings, etc.)
1 4-5
Evaluation of Life-Safety, Damage Reduction,
and Neighboring Property Rights Protection Criteria
** Note – This does not include the technical criteria (depth and velocity) being evaluated
through additional quantitative analyses.
Scale: 0 (Not Considered) – 10 (Fully Considered)
Flood Damage Resistant
Materials
6 7-8
Structure Design
4-5 7-8
Freeboard
8
8
Flood Damage
Reduction Criteria
Analysis of Impact on
Other Properties.
2
Analysis required if
doing a LOMR.
8
Mitigation of Impact on
Other Properties
1
Mitigation only
required if working in
the floodway and
mitigation only related
to change in flood
elevation.
8
Public Notification
1
Minimal notification as
part of LOMR.
9-10
Neighboring Property Rights
Protection
Public Comment
3
Can comment through
P&Z for large projects.
9
AIS Attachment 4
Page 14 of 22
Flood Damage
Reduction
Criteria
Freeboard
8
8
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