HomeMy WebLinkAboutComplete WRAB Packet 3-17-14
WATER RESOURCES ADVISORY BOARD MEETING
MEETING DATE: Monday, 17 March2014
MEETING TIME: 7:00 p.m.
MEETING LOCATION: Yards Conference Room
5050 E. Pearl
Agenda Highlights
:
1.Call to Order (7:00 p.m.)
2.Approval of the 12and 24 FebruaryMeeting Minutes(7:00p.m.)
3.*Public Comment (7:05 p.m.)
4.Information Item –Stormwater and Flood Management UtilityCIP Preview.
(7:45p.m.)
5.Matters (9:00p.m.)
a.From the Board
b.From Staff
6.Future Schedule (9:15p.m.)
7.Adjournment (9:30p.m.)
* Public Comment Item
Information
: Contact the WRAB Secretary, Laurel Olsen-Horen(303) 441-3203or
olsenl@bouldercolorado.gov. Packets are available in the reference section of the Main
Library and on-line at http://www.bouldercolorado.gov, Departments, Public Works,
Agenda item times are approximate.
Utilities, Water Resources Advisory Board.
CITY OF BOULDER, COLORADO
BOARDS AND COMMISSIONS MEETING MINUTES
Name of Board / Commission:
Water Resources Advisory Board
Date of Meeting:
12 February 2014
Contact Information of Person Preparing Minutes:
Laurel Olsen-Horen 303.441.3203
Board Members Present:
Chuck Howe,Dan Johnson,Vicki Scharnhorst,Mark Squillace,Ed Clancy
Board Members Absent:
Staff Present:Jeff Arthur, Director of Public Worksfor Utilities
Bob Harberg,Principal Engineer-Utilities
Bret Linenfelser, Water Quality and Environmental Services Manager
Joe Taddeucci, Water Resources Manager
Mike Emarine,Co-Acting Water Treatment Manager
Steve Folle,Co-Acting Water Treatment Manager
Steve Buckbee,Engineering Project Manager
Kevin Clark, Engineering Project Manager
Douglas Sullivan, Engineering Project Manager
Ken Baird,Utilities Financial Manager
Laurel Olsen-Horen, Board Secretary
Meeting Type:
Regular(Rescheduled from 27 January 2014)
Agenda Item 1 –Call to Order [7:01p.m.]
Agenda Item 2–Approval of the16 December2013Meeting Minutes: [7:02p.m.]
Motion to approvethe 16 Decembermeetingminutes as presented :Motion by: Squillace;Seconded
by: Johnson
Motion Passes;4:0
Agenda Item 3–Public Participation and Comment [7:04p.m.]
Public Comment:
Justin Hoffenberg:
Mr. Hoffenberg passed out a transcription of the recording from the December
meeting. Mr. Hoffenberg viewed the overall mission for the Utilities Division. It states the Utilities
Division is meant to provide quality water services as desired by the community and that this includes
stormwater collection and conveyance. In the recording of the December meeting, the board specifically
named a community member whoseproperty seemed to outweigh the desires of the community. Mr.
Hoffenberg read an excerpt from the handout of the transcription from the December WRAB meeting. The
reference of placing a 100-year channel through resident’s properties would absolutely cause resistance and
outrage. However,in many community events since the flood, Mr. Hoffenberg has yet to hear that solution
being suggested by staff. Does thestatement read from the December transcription represent the position of
the board?
[Board member Clancy arrived at 7:07 p.m.]
Scott Hoffenberg:
Mr. Hoffenberg passed out a handout to the board members. The homes along Gregory
Creek have encroached upon the creek bed more than any other tributary in the city and it really needs to be
th
paid attentionto. The 1995 study of the PennsylvaniaAveand 7streetculverts.Engineering there was
there to increase the capacity, it was never done though. There is a hazardous analysis planned for Gregory
Creek. When will this analysis be done? The neighbors would like to know what the analysis will do for the
residents. The city has stated a desire to acquire easements along all tributaries in the city. Gregory Creek
neighborhood is one of the most neglected areas in the cityin regards to easements and access.This area
needs to be included in the Master Plan. Acceleration of purchasing easements needs to happen. Currently,
the city doesn’t even recognize this area as a problem. The choke points (culverts on public property)
access could be granted thru temporary easements. There are very few culverts on private property that
failed.
Wendy Hoffenberg:
Ms. Hoffenberg has owned and lived in her property for 25 years. She is also on
faculty at Flatirons Elementary School. The principalat Flatirons is also the mayor of Jamestownand thus
has not been able to attend any WRAB meetings.Ms. Hoffenberg wishes to convey the principal’s thoughts
and comments to the board. Floodwaters on school grounds were not documented properly. Closing
PennsylvaniaAve will negatively impact the schoolto a level which would be unacceptable. To construct a
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roundaboutwould not be a safe option for student drop-off. The sidewalk along 7remains closed and is a
very dangerous situation for the studentsas they are diverted onto the street when walking to and from
WRAB Minutes
12 February 2014
Page No.1
school. The 7 th St. culvert has flooded the school many times in the past. The district has been contacted
and is aware of the ongoing issue. Flatirons isdesignated asa critical facility for community gathering
during an emergency, therefore, proper attention to the property needs to be given.
Roger Keonig:
Thank you to the staff for hostingthe community floodplain maps with the mark-ups. IT’s
helpful for everyone to see the process. Gregory Creek neighborhood is still not officialas they are still not
on the UDFCD mapping. When will Gregory Creek neighborhood become official? Moving forward, the
neighbors understand there are dollars available for an engineering study. Flood mitigation planning needs
to occur for GregoryCreek so the neighborhood can become “official” to begin moving forward.
City staff answered some questions and made remarks to some of the comments made during public
comment.
Agenda Item 4–Information Item –2013 Year in Review [7:29p.m.]
Jeff Arthurand Utilities staff presented the itemto the board.
Power point presentation given for item.
Executive Summary from the Packet Materials:
A significant portion of the work performed by the Utilities Division relates to the day-to-day operations
and maintenance of existing infrastructure. While the WRAB has a very limited role in these activities,
recommendations on capital improvements, master plans, and policy issues have asignificant impact on
operations. This memorandum provides an overview of 2013 operations to provide the WRAB with
additional context for upcoming agenda items where the board will be asked to make recommendations.
WRAB Discussion Included:
Concerns regarding relieving surplus water during spring run-off and how the tributaries are going
to handle the “overload.”
The possibility of using water storage reservoirs for flood mitigation.
The city’s current practice of operating under an arsenic waiver.
The city’s current practice for lining and its feasibility to keep up with the infiltration rates we
have in the area.
There is a 2008 report (WW Collection System Master Plan) that studied the sewer system with
Tier 1, 2, and 3. There were four Tier 1’s identified. Were those ever addressed? Staff response: in
all cases except for one, the projects are outside of the six-year CIP.
There seems to be a practice of dollarsbeing spent on studies; will there be enough funds for the
outlined projects?
Construction along US 36 and does it create any flood impacts to the city?
Agenda Item 5 –Information Item –Water Utility CapitalProgram (CIP) Preview
[8:45p.m.]
Utilities staff presented item to the board
Executive Summary from the Packet Materials:
This information item is intended to providean update regarding Water Capital Improvement Program
(CIP) issues ahead of the formal budget process by providing:
Background information
Flood update
Project updates
Schedule of key milestones
The formal CIP budget discussion will begin in April with a WRAB recommendation scheduled in June.
Therefore, no formal action by the WRAB is requested at this time.
WRAB Discussion Included:
What is the general expense split between transportation and utilities fundsfor current projects
(i.e. Arapahoe Ave?) Staff response: staff did a preemptive look into the water system with the
Arapahoe resurfacing project. It was found that the main is in good shape. The storm sewer
needed to be lowered, which required the lowering of some service lines. Generally,if it’s water
related, utilities pays for it. Anytime there are large transportation projects, the utilities
engineering division tries to piggyback on the project as the roadways are typically already set up
for construction.
The Asset Management Plan came before WRAB previously. WRAB voted for funding at 70-75%
WRAB Minutes
12 February 2014
Page No.2
level of service, perhaps bringing the three new board members up to speed would be helpful for
the CIP discussion as it moves forward.
Are therean average number of main breaks per annum? Staff response: Since 2006 there has
been an average of 70 main breaks per year.
Transmission lines in Boulder Creek were damaged during the flood, were they repaired? Staff
response: They have been repaired.
Agenda Item 6–Matters [9:38p.m.]
From the Board:
Board member Scharnhorst brought up the below matter(s):
Appreciated receiving the survey letter sent out to Boulder residents for gathering information on
how they were impacted by the flood.
Board member Johnsonbrought up the below matter(s):
Staff’s work plan with moving forward with the CIP looks good.
Board member Clancy brought up the below matter(s):
Agenda 4 didn’t mention any of the conveyance issues we had over the past year.
From Staff: [9:41p.m.]
Upcoming press release regarding the city’s plan to move forward with debris removal in the
city’s tributaries.
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City was awarded aresiliency grantfrom the Rockefeller Foundation. April 28there will be a
kick-off event. There may be an opportunity for a member from the board to participate.
The city is compiling a Flood Community Guide to help residents prepare for future events.
WRAB will be able to review.
The city has been partnering with CU, NCAR and other agencies to research all facets of how the
flood impacted community members.
Agenda Item 6–Discussion on Future Schedule [9:44p.m.]
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February 24meeting will focus on the wastewater CIP. The March meeting would focus on stormwater
and flood management.
Agenda Item 9–Adjournment [9:51p.m.]
There being no furtherbusiness to come before the Board at this time, by motion regularly adopted, the
meeting was adjourned at 9:51p.m.
Motion to adjourn by: Johnson; Seconded by: Squillace
Motion Passes 5:0
Date, Time, and Location of Next Meeting:
The next WRAB meeting will beMonday, 24February 2014 due to the President’s DayHolidayat 7:00
p.m., in the Municipal Service Center Conference Room; 5050 E. Pearlunless directed by staff or the
board.
APPROVED BY:ATTESTED BY:
____________________________________________________________________
Board ChairBoard Secretary
____________________________________________________________________
DateDate
An audio recording of the full meeting for which these minutes are a summary,is available on the Water
Resources Advisory Board web page.
WRAB Minutes
12 February 2014
Page No.3
CITY OF BOULDER, COLORADO
BOARDS AND COMMISSIONS MEETING MINUTES
Name of Board / Commission:
Water Resources Advisory Board
Date of Meeting:
24February 2014
Contact Information of Person Preparing Minutes:
Laurel Olsen-Horen 303.441.3203
Board Members Present:
Chuck Howe,Dan Johnson,Mark Squillace,Ed Clancy
Board Members Absent:
Vicki Scharnhorst
Staff Present:Jeff Arthur, Director of Public Works for Utilities
Bob Harberg,Principal Engineer-Utilities
Bret Linenfelser, Water Quality and Environmental Services Manager
Chris Douville,
Douglas Sullivan, Engineering Project Manager
Pieter Beyer, Civil Engineer II
Ken Baird,Utilities Financial Manager
Laurel Olsen-Horen, Board Secretary
Meeting Type:
Regular
Agenda Item 1 –Call to Order [7:01p.m.]
Agenda Item 2–Approval of the12 February 2014Meeting Minutes: [7:01p.m.]
Item deferred until the 17 March meeting.
Agenda Item 3–Public Participation and Comment [7:01p.m.]
Public Comment:
Carl Norby:
(Wan Norby, Priscilla White, Fleet White, Cory Robinson all pooled time for Carl)
The September flood caused a lot of damaged to Mr. Norby’s neighborhood in FrasierMeadows(FM).
Residents would like to work with staff on resolutions to mitigate this kind of flood result in thefuture.
Residents have pointed out system upgrades that would help the entire city. FM is somewhat isolated in its
type of damage as it was all within the walls of the properties, not necessarily to the land surrounding the
properties. FM didn’t fall intoeither category (stormwater and floodwater or wastewater), they fell into
both stormwater and sanitary sewer system. Mr. Norby sent the board an email earlier in the day
summarizing what happened during the flood and as a result ofthe flood. The problemsFM hascaused
many people in the community a lot of grief. What did the City Councilsay about taking care of the worst
disaster the city has ever seen? Council did not have an answer for that question. City Councilshould be
directing WRAB for adviceon where to budget for fixing the problem areas. Bear Creek; US 36 to
Baseline was one of the hardest hit areas in the city. The channel is in dire need of being cleared of debris,
but that is the University’s responsibility.
Questions from the board:
Has the FM neighborhood had any discussions with the University? Mr. Norby was toldthat the
University has not done anything since the flood event. FEMA told Mr. Norby that whoeverowns
the creek is responsible for maintaining it and may alsobeliable.The proper individualwithin CU
has been notified and will be in contact with the residents shortly.
What would be involved with staff looking into the suggestions made by Mr. Norby? Staff
response: city staff is still collecting data to enable the city to putall of the pieces together to
determine priority areas. As part of the CIP discussion, WRAB will be discussing which items are
priority items.
Have there been any solutions looked into for the sanitary sewer system? Mr. Norby stated that
FM residents had pointed out some shortfalls within the system. It was recommended that the lines
in FM be scoped with a camera so we can see what issues are present. FM has a long history of
issues with the sanitary sewer system.
WRAB Minutes
24 February 2014
Page No.1
Agenda Item 4–Information Item –Wastewater Utility CIP Preview [7:27p.m.]
Douglas Sullivan presented the itemto the board.
Power point presentation given for item.
Executive Summary from the Packet Materials:
This information item is intended to providean update regarding Wastewater Capital Improvement
Program (CIP) issues ahead of the formal budget process by providing:
Background information
Flood update
Project updates
Schedule of key milestones
The formal CIP budget discussion will begin in April with a WRAB recommendation scheduled in June.
Therefore, no formal action by the WRAB is requested at this time.
WRAB Discussion Included:
Condition monitoring has worked well for other organizationsand the feasibility of using it for the
city’s infrastructure.
The city’shistorical record and its success forprojecting maintenance needs in the past.
The city should benchmark our treatment plant to other communities (AWWA).
Superior did not see any sanitary sewer failures which were abundant in Boulder. Staff response: a
vast majority of our system is made of clay pipe;Superior does not have that type of
infrastructure.
What allows the city to offer lower utility rates than places such as Fort Collins? Fort Collins has
two plants.
Have any other Front Rangecommunities banned phosphorus? Staff response: no, that kind of
decision would be more effectiveon a state-wide level. Education is vitalforthe reduction of
phosphorus.
Can the city take wastewwater samples along the way whenthe floatis sent down the main line?
The city is able to monitor effluent characteristics at other locations.
Agenda Item 5–Matters [8:57p.m.]
From the Board:
Board member Clancy brought up the below matter(s):
There is a lot of snow out there now. What is the city’s Plan B for a large run-off? Staff response:
the city is working with Boulder Co. and the Office of Emergency Management. The run-off may
occur earlier and last longer than usual. The shape of the water shed upstream is not good. Any
large rain has the potential to bring with it a lot of sediment.
What about the city’s ditch system? Is anyone going to be clearing them out? Staff response: the
ditches that carry stormwater; the city tends to have a good relationship with the ditch company.
Irrigation ditches have an incentive to clear out the sediment as they are still responsible to deliver
water to their customers.
How many responses from the survey has the city received thus far? We have received around
1,350.
From Staff: [8:58p.m.]
As of today, contractors are out clearing sediment and debris from the creekbeds. (Ch. 4, 21:50)
New Water Treatment Manager has been hired;Tom Settle will start in early March.
Five applications were received for the vacant seat on WRAB. Council will make their selection in
March and the new board member will begin in April.
Agenda Item 6–Discussion on Future Schedule [9:08p.m.]
March will focus on stormwater and flood managementCIP preview.
If any board members anticipate missing any of the meetingsin April, May and June, please let staff know
WRAB Minutes
24 February 2014
Page No.2
Agenda Item 9–Adjournment [9:10p.m.]
There being no furtherbusiness to come before the Board at this time, by motion regularly adopted, the
meeting was adjourned at 9:10p.m.
Motion to adjourn by:Squillace; Seconded by: Clancy
Motion Passes 4:0
Date, Time, and Location of Next Meeting:
The next WRAB meeting will beMonday, 17 March2014at 7:00 p.m., in the Municipal Service Center
Conference Room; 5050 E. Pearlunless directed by staff or the board.
APPROVED BY:ATTESTED BY:
____________________________________________________________________
Board ChairBoard Secretary
____________________________________________________________________
DateDate
An audio recording of the full meeting for which these minutes are a summary,is available on the Water
Resources Advisory Board webpage.
WRAB Minutes
24 February 2014
Page No.3
C I T Y OF B O U L D E R
WATER RESOURCES ADVISORY BOARD
INFORMATIONITEM
MEETING DATE: March 17, 2014
AGENDA TITLE
:Informational Item –Stormwater and Flood Management Utility Capital
Improvement Program (CIP) Preview
PRESENTERS:
Jeff Arthur,Director of Public Works for Utilities
Robert Harberg, Principal Engineer-Utilities
Annie Noble, Flood and Greenways Engineering Coordinator
Douglas Sullivan, Engineering Project Manager
Kurt Bauer, Engineering Project Manager
Katie Knapp, Engineering Project Manager
Pieter Beyer, Civil Engineer II
Ken Baird, Financial Manager for Utilities
EXECUTIVE SUMMARY
This information item is intended to provide an update regarding the Stormwater and Flood
Management Utility (Utility) Capital Improvement Program (CIP) issues ahead of the formal
budget process by providing:
Background information
Flood update
Project updates
Schedule of key milestones
The formal CIP budget discussion will begin in April with a WRAB recommendation scheduled in
June. Therefore, no formal action by the WRAB is requested at this time.
BACKGROUND
The Utilities Division’s mission is to provide quality water services, as desired by the community,
in a manner which emphasizes efficient management of fiscal and natural resources, and protects
human and environmental health.
The city’s Stormwater and Flood Management Utility (Utility) was created in 1973 as an
enterprise utilityand funded by a service charge and connections fees which provides
approximately $6,000,000 of revenue each year.
AGENDA ITEM#IV; PAGE1
The Comprehensive Flood and Stormwater (CFS) Master Plan is an overarching document that is
intended to present key issues, programs, projects, and associated budgets for the Utility.Unlike
other city master plans, CFS does not identify specific Capital Improvement Projects. Rather it sets
the agenda for implementing programs and activities and provides guiding principles, program
Attachment A
elements and action items as summarized in the Executive Summary–see . The
CFS Master Plan was accepted by City Council in November 2004.
Stormwater management focuses primarily on what is called the minor (2-5 year) storm events,
whereas flood management focuses on major (100-500 year) storm events. In the past, most CIP
funds have been allocated to flood management projects because of the significant life safety and
Attachment B
property damage risk in Boulder.presents a summary of Utility CIP project
expenditures from 1990-2012.
The CFS Master Plan is organized and focuses on the following programs:
MAJOR DRAINAGEWAYS
The city has a comprehensive floodplain management program designed to identify flood risks,
mitigate the risks of flooding, minimize loss of life and property damageand support recovery
following a major flood event. Major components of the city’s floodplain program include:
mapping, mitigation master planning and construction, property acquisition and flood protection
through land use regulationsand flood preparedness. The flood management program is focused
onflood hazards associated with major drainageways that pose the highest risk to life safety and
Attachment C
property damage. Major drainageways within the City of Boulder are depicted in .
Because of the significant risk to life safety and property damage in Boulder, a focus of this
program is onemergency preparedness, flood warning, public awareness and self help techniques.
Floodplain mapping provides the basis for the city’s floodplain management program by
identifying the areas subject to flooding. Flood mitigation master planning typically follows each
mapping study update. During the mitigation master planning process,potential flood mitigation
improvement projects are identified and evaluated based onabenefit to cost reviewusing a
Federal Emergency Management Agency method of analysis prior to investing public funds in
such improvements.Flood mitigation projects are prioritized based on the life safety threat.
The primary guiding documents for this program are:
Major DrainagewayPlanning, Boulder and Adjacent County Drainageways –Phase B
(1987)
Fourmile Canyon and Wonderland Creek Flood Mitigation Plan (2009)
The highestpriority projects identified in the 1987 document have been completed. Other projects
identified in this document are beingreviewed based on new flood modeling information. Because
of the increased complexity of hydraulic modeling, mapping, hazard identification, benefit/cost
analysis, environmental regulations and public involvement,subsequent studies have been focused
on individual drainageways. An example is the South Boulder Creek flood mitigation planning
effort that is currently in progress. These planning studies typically take many years to complete.
AGENDA ITEM#IV; PAGE2
The Fourmile Canyon and Wonderland Creek flood mitigation planning encompassed nearly a
decade. The progression of study typically starts with base mapping and hydraulic modeling
leading to an updated floodplain mapping study that is submitted to FEMA for review and
approval. FEMA review can takeseveral years to complete and effective mitigation planning is
generally not feasible until mapping changes have been finalized.
Major drainageway improvement projects aregenerally multi-year projects and often require
phasing to fund the significant costs.A single culvert can range from several hundred thousand
dollars for a two-lane roadway crossing to multiple million dollars for a major arterial roadway
crossing. In most cases, significant property acquisition is required, including the demolition and
Attachment B
removal of existing private structures. Refer to for more detailed information about
the historic cost of major drainageway and other improvement projects.
STORMWATER MANAGEMENT
Stormwater Management refers to the city’s stormwater collection system that conveys rainfall and
runoff to the major drainageways. The stormwater collection system is comprised of storm
sewers, culverts and ditches that convey stormwater away from developed property and roadways
to the major drainageways. Thereare approximately 160 miles of city owned and maintained
stormwater pipe. Most of this pipe was installed after 1960 andlarge areas of the city were
developed with no storm drainage features other than paved streets that convey rain water runoff.
The city developed a stormwater management program to meet USEPA requirements regarding
non-agricultural stormwater discharges under the National Pollutant Discharge Elimination System
(NPDES) Stormwater Program. The program is designed to prevent harmful pollutants from being
discharged into local water bodies. The City of Boulder is a Municipal Separate Storm Sewer
System (MS4), and has an MS4 permit to meet NPDES Stormwater Program permit requirements.
The primary guiding document for stormwater management is the Stormwater Master Plan (SMP)
which was completed in 2007. The SMP is a comprehensive evaluation of the city’s stormwater
collection and stormwater quality system. The goal of the Boulder SMP is to proactively manage
stormwater runoff to protect water quality and to minimize impacts of localized and downstream
flooding by identifying infrastructure improvements for the collection, conveyance and treatment
of stormwater runoff from within the City. The SMP Executive Summary is presented as
AttachmentD
.
FLOOD UPDATE
As a result of the recent flood, there is an increased interest by the public in flood mitigation
improvements. Assessing flooding impacts and analyzing the benefits and costs associated with
stormwater and flood mitigation, in addition to the public engagement process will take years to
complete for the stormwater system and all major drainageways. It may be desirable to accelerate
mitigation improvements. Additional funding in the form of Stormwater and Flood Management
Utility rate increases would need to be considered.
AGENDA ITEM#IV; PAGE3
ANALYSIS
Attachment E
presents a list of CIP projects and potential funding amounts being considered as
discussed below.
MAJOR DRAINAGEWAYS
The Greenways and Flood 2014-2019 CIPs focused on projects along Wonderland Creek between
nd
Foothills Highway and Winding Trail Drive and Fourmile Canyon Creek between 22Street and
Violet Avenue. Funding was also shown for South Boulder Creek. The 2013 flood event resulted
in varying flood extents along Boulder Creek and the 14 tributaries.Documentation of the flood
event revealed discrepancies between the FEMA regulatory floodplain limits and the extent of
actual flooding in the Fourmile and Wonderland Creek drainages.In particular, Fourmile Canyon
Creek deposited significant amounts of sediment in andalong the historic drainageway. This
caused water to flow in other adjacent areas.
The city has commissioned an engineering consulting firm to revisit the floodplain mapping for the
spill area along Fourmile Canyon Creek.The design of the projects along Fourmile Canyon Creek
has been put on hold pending updated 100-year flow data from this evaluation.
Typically flood mitigation projects are identified as part of a flood mitigation planning study,
which usually follows a flood mapping update and approval by FEMA. An overall schedule for
Attachment F
major draingeway CIP planning is presented as .
Capital improvements required to mitigate flood hazards require multi-year funding or the issuance
Attachment G
of bonds.presents representative historic cost information about various projects as
well as ballpark estimated costs for 100-year flood mitigation improvements for various
drainageways.
Prior to the September 2013 flood disaster, the city had several mapping and mitigation projects
underway. The schedules of those projects are being adjusted to allow consideration of new
LiDAR data and new information from the flood event and are listed below:
Current Mapping Updates
Upper Goose Creek and Two-Mile Canyon Creek
Skunk Creek, Bluebell Canyon Creek and King’s Gulch
These mapping study updates should be completed later this year based on the new
LiDAR derived topographic base mapping and analysis of the extent of flooding from
the September 2013 flood disaster. Flood mitigation studies for these drainageways are
anticipated to begin in 2016 and funding is shown in the CIP in 2017 and 2018.
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Boulder Sloughfrom Broadway to downstream of 30St.The construction of
improvements along the Boulder Slough between 30th St. and Foothills Parkwayis
underway in conjunction with the Boulder Junction project and a Letter of Map
Revision (LOMR) will be done following the construction.
AGENDA ITEM#IV; PAGE4
Current Flood Mitigation Planning
Boulder Creek, Gregory Canyon Creek and Bear Canyon Creek.
The floodplain mapping for these areas was morerecently updated and appears to
accurately reflect actual 2013 flood disaster conditions, but this will be confirmed. This
study will identify opportunities for mitigation and help prioritize future work. This
study will not only consider 100-year floodimprovements, but will also look at
improvements for more frequent storm events. This study will begin in early 2014.
Funding is shown in the CIP in 2015 and2016 for Bear Canyon Creek, Gregory Creek
and Boulder Creek, with additional funding in 2017 for Boulder Creek.
South Boulder Creek
This mitigation study will be completed this year. The proposed improvements will be
taken through an extensive public process prior to final design and construction.
Additional funding is shown in this year’s CIP in 2015 and 2016, in addition to the
bond funds that were shown in previous CIPs. Phase two of the South Boulder Creek
Flood Mitigation Improvements was listed as unfunded in previous CIPs, but was
included in 2020 in this CIP. As a result of the recent flood disaster, the city may be
eligible for post-disaster grant funding for improvements along South Boulder Creek.
On-going Capital Improvements
Fourmile Canyon Creek
Funding continues to be shown in the CIP for Fourmile Canyon Creek as in last year’s
CIP, with additional funding shown in 2020. Once the information from the September
2013 flood disaster is reconciled with existing hydrologic and hydraulic modeling, we
will adjust and move forwardwith the projects identified in the Fourmile Canyon Creek
Mitigation Plan. Additional mitigation projects may be identified as a result of the
2013 flood.
Flood Recovery
Flood recovery work is well underway including debris and sediment removal from the city
maintained drainagewaysto restore capacity.Bids have been received for permanent restoration
of drainageway features and a contract will be issued in the near future. The total cost of flood
recovery work associated with the major drainageways is approximately $6-8 million and
previously appropriated funds intended for the Wonderland Creek flood mitigation project are
being used to cover these expenses.
It is estimated that 75% of the “eligible”costswill be reimbursed by FEMA with reimbursement
payment expected in late 2014 or early 2015.FEMA provides reimbursement onlyfor restoration
of facilities maintained by the city prior to the flood and only for restoration to pre-flood
conditions.There is the possibility that the State of Colorado may appropriate money to provide an
AGENDA ITEM#IV; PAGE5
additional 12.5% reimbursement of expenses to local governments. The city will need to determine
the best approach for funding the unreimbursed costs.
STORMWATER MANAGEMENT
The 2014-2019Utility CIP includes major drainageways projects and stormwater management
projects. The major drainageway section was discussed above. This sectionprovides an overview
of the stormwater management programs and projects. The stormwater management program
currently includes the following four projects/components: Upper Goose Creek, Stormwater
Quality Improvements, Storm Sewer Rehabilitation, and Transportation Coordination. The CIP
funding allocations are based in part on the Stormwater Utility Master Plan (SMP)
recommendations -completed in 2007. The SMP included a comprehensive list of CIP
recommendations organized accordingly to three Tier levels of prioritization. City staff is in the
process of reviewing the various flood data available from the September 2013 flood event. Staff
is in the process of reconcilingthe flood information with the master plan recommendations and
developingan updated set of stormwater quality and drainage CIP project priorities.
Following the September 2013 flooding disaster, city staff is recommending increased funding in
two of the four areas, and creating a fifth area to specifically address localized drainage
improvement projects. This recommendation is based on the need to address the extensive
flooding that occurred in numerous areas throughout the City.
Flood Recovery
Flood recovery work is well underway including debris and sediment removal from inlets, catch
basins, manholes, culverts and stormsewers. It is anticipated that a construction bid will be
nd
awarded for additional work in the 2quarter of 2014. The total cost of flood recovery work
associated with the stormwater management system is estimated to be approximately $1-2 million
and will need to be made available in 2014. It is estimated that 75% of this cost will be reimbursed
by FEMA. Payment is expected in late 2014 or early 2015.
Upper Goose Creek
The Upper Goose Creek drainage improvements project was identified as the top stormwater
drainage priority in the SMP. This project was identified to include pipe replacement, new storm
th
drains, and channel improvements. This project area is bounded on the west by 9Street, on the
th
east by 19Street , on the south by North Street and on the north by Evergreen. This area has
experienced flooding on numerous occasions in the past.The priority of the Upper Goose Creek
project will be re-evaluated in light of the September 2013 flood disaster.
Stormwater Quality
The Stormwater Quality Improvements program is becoming a higher priority because of
stormwater quality regulations and the impact of stormater discharged to Boulder Creek and its
tributaries through numerous outfalls. This program has been historically funded at $100,000 year.
Staff has identified additional water quality projects that would require increased funding in the
futureand is considering a recommendation that this funding be increased to $150,000 annually.
AGENDA ITEM#IV; PAGE6
Storm Sewer Rehabilitation
Post-flood inspections have revealed several storm collection system assets which require repair
due to normal wear and tear.Many of these include corrugated metal pipes which have severe
corrosion. Currently the city funds storm sewer rehabilitation at a rate of approximately $250,000
per year.
Transportation Coordination
The community has recently supported additional funding for transportation projectsthrough a
voter approved bond measure. Theadditional projects have resulted in a corresponding increase in
the associated stormwater infrastructure needed. The current funding to coordinate with and
support transportationprojectsis $250,000 per yearbut this may need to be increased to support
the additional transportation projects.
Local Drainage Improvements
The September 2013 flood disaster made it clear that there are significant localized stormwater
conveyance issues throughout the City. To begin the process of evaluating and prioritizing
improvement alternatives and funding certain improvements additional funding is being
considered.
FINANCIAL CONSIDERATIONS
The Utility operates as an enterprise utility as defined in State law under the Taxpayer Bill of
Rights (TABOR.) An enterprise isa government owned business authorized to issue its own
revenue bonds and receiving less than 10% of its annual revenue in grants from all Colorado state
and local governments. Total operating and transfer expenses are about $3.5M, and the 6-year CIP
approved in the 2014 budget and debt payments averages $5M per year. In 2013, customer
billings accounted for approximately $5.5M in revenue, and plant investment fees contributed
about $600,000. In some years, another significant source of funding is federal grants and/or
Urban Drainage Flood Control District funds.
The 2014 rate for a single-family residential customer with up to a 15,000 square foot lot is $7.69
per monthand those with lots between 15,000 and 30,000 square feet paying $9.61, and those over
30,000 square feet paying $11.54. All other properties pay a fee based on a runoff calculation.
For example, a grocery store in town pays about $880 per month, and a local hotel pays $224per
month.Compared to 15 other utilities in the Front Range,the single-family residential rate in
th
Boulder is the 5highest. Ft. Collins and Longmont are currently the highest in the survey at
around $13 per month. Fort Collins implemented severalyears of double digit rate increases after
the 1997 Spring Creek flood, including a 45% increase in 2002 following master plan updates.
Their rate has remained the same since 2004. They have been working to build for 100-year flood
protection in their 12 drainage basins within a 35 year timeframe.
Following the September 2013 flood, Longmont increased Storm Drainage fees from $7.77 to
$13.05 for residential customers. They are working to make improvements for a 100-year flood,
and anticipate needingto bond for an additional $20M.
The financial plan adopted for 2014 for the Utility anticipated annual rate increases of 3%.
Continuing this level of funding would not allow for the additional mitigation improvements
AGENDA ITEM#IV; PAGE7
outlined in this memo, and dependingon the level of FEMA reimbursement for flood costs, may
require projects or operations to have reduced funding. If Boulder’s stormwater fee were increased
to an amount similar to Longmont and Ft. Collins, this would bring in approximately $3.8M in
additional revenue annually at a cost of a little over five dollars per month on a single-family
residential bill. This increase, along with ongoing inflationary increases, would provide sufficient
Attachment D
revenue to fund the additional projects highlighted in based on preliminary
Attachment G
estimates. The ballpark estimate in shows potential costs for providing 100-year
flood mitigation costs. To provide the bond capacity to fund the estimated cost of over $300M,
rates would have to increase over 500%.
SCHEDULE OF KEY MILESTONES
Budget Schedule
The current schedule of major budget milestones is provided below. Elements involving the
WRAB are highlighted in bold italics.
WRAB Preliminary CIP Budget Discussion -April 21, 2014
Budget Guidelines to Departments -April 2014
WRAB Draft CIP Review -May 19, 2014
Proposed Budget Submittal to City Manager -May 2014
WRAB Recommendation on CIP/Budget -June 16, 2014
Departmental Budget Review by City Manager -May/June 2014
Planning Board Recommendation onCIP -August 2014
City Council Study Session on CIP -August 2014
City Council Study Session on Budget -September 2014
City Council Consideration/Adoption of Budget –October/November 2014
ATTACHMENTS:
Attachment A: Comprehensive Flood and Stormwater Master Plan Executive Summary
Attachment B: Historic Flood Project Expenditures (1990-2012)
Attachment B: Map of Major Draiangeways
Attachment D: Stormwater Master Plan Executive Summary
Attachment E: List of CIP Project FundingConsiderations
Attachment F:Major Draingeway CIP Planning Schedule
Attachment G: 100-year Flood Mitigation Costs
AGENDA ITEM#IV; PAGE8
EXECUTIVE SUMMARY
Stormwater Quality Management.
Emergency Preparedness and Day-to-Day
I
NTRODUCTION
Operations.
The Comprehensive Flood and Stormwater
Capital Improvements and Land
Utility Master Plan (CFS) provides a framework
Management.
for evaluating, developing, and implementing
various programs and activities in the Utility
7KH&)68WLOLW\3ODQ·VPDLQREMHFWLYHVDUHWR
within the scope of the available budget. The
address: (1) flash flood hazards; (2) stormwater
CFS replaces the 1989 Comprehensive
quality; (3) stormwater drainage; (4) program
Drainage Utility Master Plan (CDUMP).
integration and implementation; and (5)
financial considerations.
The CFS is the result of the periodic need to
update programs and activities to satisfy
AD
REA ESCRIPTION
current local interests, accommodate changing
trends, philosophies, regulations and
The Boulder Creek Watershed encompasses
standards, ensure maximum effectiveness and
some 440 square miles and extends from the
cost efficiency, and meet evolving community
Continental Divide to the high plains east of
goals and objectives.
the City. There are 15 major drainageways (or
creeks) in Boulder, within which a total of 17
The Stormwater and Flood Management Utility
sub-basins have been delineated. The
(Utility) is responsible for the administration of
tributary drainageways all eventually feed to
the City's flood management, stormwater
Boulder Creek north of the Valmont Reservoir.
quality, and stormwater drainage programs.
Its responsibilities include:
7KHVWXG\DUHDLWVHOILVQHDUO\´EXLOWRXWµ
resulting in a highly urbanized drainage
Administration and Operations.
setting. The natural hazards related to
stormwater and flood management are
Utility Rates and Finance.
particularly complicated by the fact that space
is at a premium and that so many structures
Program Development and Management.
are within the floodplain.
System Maintenance and Restoration.
PP
UBLIC ROCESS
Flood and Stormwater Regulation and A Community-Review Group (CRG) was used
Compliance.
WRSURYLGH´UHDOWLPHµLQSXWWRWKHDQDO\VLVDQG
draft recommendations for the CFS Master
System Master Planning and Design.
Plan. The CRG was created based on the key
interests affected by the CFS.
Public Education and Community
The Independent Review Panel (IRP), a panel of
Outreach.
flood hazard experts, also participated in the
CFS development process.
Flood Prediction.
ES-1
Boulder floodplain policies have not been
The Water Resource Advisory Board (WRAB) updated since adoption of the CDUMP. As a
met twice in 2003 and discussed key issues result, our local floodplain management
and the master plan process. program has fallen behind the progression of
national and regional trends and philosophies,
FM
and the nonstructural floodplain policy
LOOD ANAGEMENT
objectives outlined in the early years of our
The Flood Management Program is
floodplain management program have never
responsible for all programs and activities
been fully realized.
related to local flooding and the floodplain.
The City of Boulder is extremely vulnerable to
&XUUHQW3URJUDP(OHPHQWV
flash flooding due to its geographical location
Current flood management program elements
at the base of the Rocky Mountains. Within the
include floodplain mapping, risk assessments,
&LW\RI%RXOGHU·V\HDUIORRGSODLQWKHUHDUH
regulations, flood information and insurance,
thousands of people and approximately 3,600
emergency preparedness, property acquisition,
structures with an assessed valuation of almost
and flood mitigation capital improvements.
$1 billion.
*XLGLQJ3ULQFLSOHV
The City continues to grow through a
combination of new development and
Using national and regional trends and
redevelopment activity. Within the floodplain,
philosophies, current and past local policies,
these activities pose additional potential for
and recommendations from the IRP and CRG
hazards due to flash floods.
DVDEDFNGURSIRUXSGDWLQJ%RXOGHU·VIORRG
management program, staff is recommending
Recent projections indicate that almost 5
five guiding principles:
percent of the parcels of land designated with
redevelopment potential have greater than 50
1.´3UHVHUYH)ORRGSODLQVµ
percent of their land area within the high
hazard or conveyance flood zones. Current
2.´%H3UHSDUHGIRU)ORRGVµ
City regulations would significantly restrict
redevelopment of these parcels. Almost 20
3.´+HOS3HRSOH3URWHFW7KHPVHOYHVIURP
percent of the parcels of land designated with
)ORRG+D]DUGVµ
redevelopment potential have greater than 50
4.´3UHYHQW$GYHUVH,PSDFWVDQG8QZLVH
percent of their land area within the 100-year
8VHVLQWKH)ORRGSODLQµ
floodplain. Current City regulations do not
restrict redevelopment of these properties but
5.´6HHNWR$FFRPPRGDWH)ORRGV1RW
require suitable flood protection measures.
&RQWURO7KHPµ
However, these properties would still be
subject to flood damage from larger flood
events. Many of these parcels are located in
the Boulder Valley Regional Center and the
downtown business area which will be
impacted by Boulder Creek flooding.
ES-2
5HFRPPHQGHG)ORRG0DQDJHPHQWThere has been a strong community interest in
offering a greater balance of non-structural
3URJUDP(OHPHQWV
flood management program activities as part
of the overall Stormwater and Flood
Floodplain Mapping Studies Program
Management Utility program. These
recommendations will serve to help achieve
Floodplain mapping studies are essential in
this balance:
determining areas where life safety is
threatened and damage to property is likely.
Create a flood management program
resource center and program manager.
A 10-year update cycle coincides with the
&LW\·VDYHUDJHWLPHOLQHIRUXSGDWLQJQHZ
Allocate $125,000 annual funding and
citywide topographic, planimetric, and aerial
staff resources for program support.
base mapping used for the study purposes.
Enhance the flood management Web site.
In-depth analysis of floodplain mapping results
can offer insights into the associated risks and
Pursue an improved Community Rating
levels of hazard inside the floodplain. The
System (CRS) rating given available
expanded hazard information is valuable for
resources.
enhancing non-structural flood management
program activities supported by the
Research a local flood proofing program.
community.
Recommendations include:
Flood Preparedness
Adopt a 10-year update cycle for local
7KHJXLGLQJSULQFLSOHWR´EHSUHSDUHGIRU
floodplain mapping studies.
IORRGVµIRFXVHVRQIORRGSODLQHPHUJHQF\
preparedness. Flood preparedness is a critical
Include floodplain risk assessments in all
HOHPHQWLQWKH&LW\·VIORRGSODLQPDQDJHPHQW
floodplain mapping updates.
program, considering that more than 15
percent of the community is impacted by
Public Education and Flood Insurance
floodplains.
The more prepared a community can be with
7KHJXLGLQJSULQFLSOHWR´KHOSSHRSOHSURWHFW
pre-flood preparedness, ongoing monitoring,
WKHPVHOYHVIURPIORRGKD]DUGVµIRFXVHVRQ
effective warning systems, trained response,
educating the public about flooding and
and post-flood recovery, the better chance the
providing information and resources the public
risks of flooding may be managed.
may access to reduce their own exposure to
IORRGLQJ*LYHQWKDW%RXOGHULVQHDULQJ´EXLOG
Recommendations include:
RXWµWKLVDSSURDFKDOORZVWKHIORRG
management program to reach out and
Enhance coordination between the Office
benefit the community at large.
of Emergency Management and the City of
ES-3
Boulder by taking a more active role in
Evaluate the adequacy of the flood
emergency management.
protection elevation for flood proofed
structures.
Continue to enhance flood monitoring and
prediction, early warning, and multiple
Develop hazard analysis standards.
notification measures by implementing the
findings in the University of Colorado and
Seek FEMA approval of engineered
recent system evaluations.
foundation standards for crawlspaces.
Update and improve the flood response
Research limited residential flood-proofing
and flood recovery plans to address
options for structures located in lower-risk
actions by public officials and actions by
shallow flooding areas.
residents and members of the public.
Evaluate the Association of State
Develop innovative user friendly
)ORRGSODLQ0DQDJHUV´QRDGYHUVHLPSDFWµ
information materials for the public and
approach to floodplain management.
residents to follow in the event of a flood.
Seek FEMA and UDFCD acceptance of the
Floodplain Regulations
City conveyance zone (floodway).
Floodplain regulations are land use
Seek Boulder County/City of Boulder
regulations intended to regulate activities and
regulatory consistency.
development in the 100-year floodplain,
conveyance zone (or floodway), and high
Property Acquisition and Floodplain
hazard zone. They are designed to provide a
Mitigation
mechanism to address life safety and property
damage impacts by restricting certain activities
The floodplain risk assessments will provide a
and improvements in the floodplain.
more detailed framework for evaluating
floodplain management and/or mitigation
The floodplain regulatory revisions include
alternatives.
recommendations intended to better address
issues of life safety and structural safety:
The property acquisition and constructed flood
mitigation program has been very successful
Assess the adequacy of life safety
over the years. However, modern community
measures.
interests and national trends away from
structural drainageway construction have
Address floodplain mapping uncertainties.
raised questions regarding previous structurally
oriented projects that involve significant costs
Develop options for mitigating new
and raise environmental and aesthetic issues.
floodplain encroachments.
The following recommendations offer
approaches to balance structural and non-
Develop 500-year protection standards for
structural alternatives:
critical facilities.
ES-4
permit compliance is based on implementation
Floodplain risk assessments, developed in
of stormwater management programs intended
conjunction with floodplain mapping
to reduce pollutant loading from urbanized
updates, should be used to identify and
areas.
quantify life safety and property damage
risks to determine appropriate measures
Water quality in Boulder Creek and its
for property acquisition and floodplain
tributaries is a significant concern. The CDPHE
mitigation.
is considering listing Boulder Creek as an
impaired water body for E. coli bacteria
A balance of constructed flood mitigation
contamination.
projects (based on risks to life safety and of
property damage) and acquisition of
Currently, Best Management Practices (BMPs)
property (including removal of associated
LGHQWLILHGDVRSWLRQVLQWKH&LW\·V'HVLJQDQG
structures) should be applied to long-term
Construction Standards (DCS) are geared
floodplain management and preservation.
more toward new development than toward re-
GHYHORSPHQW%RXOGHULVSUHGRPLQDQWO\´EXLOW
Non-structural alternatives shall be
RXWµDQGJXLGHOLQHVIRFXVHGWRZDUGQHZ
considered and balanced with structural
development have limited applicability in
measures for floodplain planning and
denser, redeveloping areas such as the
mitigation activities.
Boulder Valley Regional Center and the
downtown business center. Therefore, more
innovative solutions need to be applied.
SQ
TORMWATER UALITY
Examples of these BMPs include porous
7KH&LW\·V6WRUPZDWHU4XDOLW\3URJUDPLV
pavements, subsurface detention, vegetated
responsible for managing local activities to
landscape filters and hydrodynamic separator
preserve, protect, and enhance water quality
devices.
DIIHFWLQJ%RXOGHU·VVWUHDPVDQGGUDLQDJHV7KH
current program has four main components:
&XUUHQW3URJUDP(OHPHQWV
Public Education
Current stormwater quality program elements
include water quality regulations, sub-basin
Water Quality Monitoring
management and stream enhancement.
Regulatory Compliance
*XLGLQJ3ULQFLSOHV
Source Control
Recommended stormwater quality guiding
principles, based on national trends and
In 2001, in response to Clean Water Act
current local policies, include:
requirements, Colorado Department of Public
Health and the Environment (CDPHE)
1.´3UHVHUYH2XU6WUHDPVµ
expanded its regulations to include regulations
for discharges from municipal storm sewer
2.´3UHYHQW$GYHUVH,PSDFWVIURP
systems for cities with populations less than
6WRUPZDWHUµ
100,000 and more than 10,000. Stormwater
ES-5
3.´3URWHFWDQG(QKDQFH2XU6WUHDP
Enhance water quality monitoring program
&RUULGRUVµ
to improve data analysis, program
evaluation and compliance tracking.
5HFRPPHQGHG6WRUPZDWHU4XDOLW\
Sub-basin Management
3URJUDP(OHPHQWV
Sub-basin management focuses on reducing
Water Quality Regulations
the impact of runoff by focusing on preventive
measures to minimize pollution at the source.
Implementation of a common approach results
Recommendations include:
in consistency throughout the Boulder Creek
watershed and provides more comprehensive,
Research BMPs oriented to redevelopment
regional protection of water quality.
and existing development in highly
urbanized areas such as the Boulder Valley
Continued water quality monitoring of the
Regional Center and the downtown
main stem of Boulder Creek will provide
business center and incorporate
information needed to evaluate the impact of
appropriate BMPs into City Ordinances
existing and new regulatory requirements such
and Standards.
as the Total Maximum Daily Limit (TMDL) and
sediment/aquatic life standards.
Integrate water quality objectives into the
City master planning process, such as
Recommendations include:
updates to the Boulder Valley
Comprehensive Plan (BVCP) and the
Update City codes and development
update to the Stormwater Management
standards to meet applicable federal and
Plan.
state regulations. Update City standards to
exceed federal and state requirements
Examine the stormwater utility rate structure
where appropriate to meet local water
to promote innovative BMPs and
quality protection needs. investment in public regional BMPs.
Ensure adequate funding for the continued Develop incentive programs to promote
participation in the WASH program and
BMPs in both residential landscapes and
WKH&LW\·VLQGLYLGXDOUHTXLUHPHQWVIRU
commercial development that are
FRPSOLDQFHZLWKWKH&LW\·V6WRUPZDWHU
innovative and exceed City requirements.
Permit.
Explore the use of subsidies, public-private
Continue to pursue opportunities to partnerships, and grant-funding to
collaborate with other communities to
implement innovative urban BMPs.
address water quality issues.
Consider special improvement districts for
targeted areas, such as the Boulder Valley
Track upcoming regulatory changes to
Regional Center and downtown business
develop the most cost effective approach
center.
to compliance.
ES-6
enhancement through the major
Increase the water quality benefits derived
drainageway planning process.
from the City's urban forest through
support of the City's Urban Forest Program
Expand the Greenways Master Plan
and tree planting programs for parks and
principals to all tributaries beyond Boulder
other City owned properties. Consider
Creek and the six tributaries currently
updating regulations and standards to
studied.
increase tree planting requirements for
new development and re-development
Use balanced approaches to drainage
projects.
solutions that provide multiple benefits,
including the water quality/quantity
Integrate multiple objectives including
benefits of preserving the stream corridor
water quality enhancement on City-owned
and its natural character.
land and in decisions regarding future
property acquisition.
Avoid hydrologic disconnect between
groundwater and surface water in stream
Develop GIS tool to prioritize water quality
channels.
improvement projects for sub-basins
using data such as potential pollutant
Implement sub-basin water quality
loading, land-use, impervious surface,
management practices and projects in
groundwater recharge and other data,
conjunction with Greenways project
some of which has been developed in the
implementation.
2000 Boulder Creek Watershed Study.
Update the Greenways Design Guidelines
Update development and re-development
to include measures to stabilize channel
regulations and standards to expand runoff
erosion and sedimentation, support fish
reduction and water conservation
and other aquatic species movement,
requirements.
protect riparian habitat, and other
measures to promote stream stability.
Stream Enhancement
Stream enhancement focuses on the stream
SD
TORMWATER RAINAGE
corridor itself. Stable stream environments are
7KH&LW\·VVWRUPZDWHUFROOection system consists
necessary for fish and other aquatic species to
of a variety of storm sewers and open drainage
survive. Riparian habitat provides a number of
ditches that collect water and divert the water
water quality and ecosystem functions.
to major drainageways.
Recommendations include:
Irrigation ditches collect stormwater in many
3URWHFWDQGSUHVHUYHWKHZDWHUVKHG·VPRVW
places in the City. Depending on the amount
FULWLFDODQGIUDJLOHDUHDV²IORRGSODLQV
of rainfall, stormwater flows may exceed the
Provide ample flood capacity and
capacity of the ditch and spill from the ditch in
freeboard, allowing for increase in riparian
an uncontrolled manner.
vegetation and roughness. Integrate
floodplains protection with stream channel
ES-7
,QWKHSDVWWKH8WLOLW\·VHPSKDVLVKDVEHHQWRresidential areas and 5-year frequency for
commercial/ industrial areas) drainage related
provide structural solutions, such as
drainageways and storm sewer facilities, to Capital Improvement Projects (CIP). This 20-
resolve stormwater and flood management year old plan should be updated to include
issues. Now, the overall guiding principles are drainage, detention, groundwater and
in place to develop a balance of structural and stormwater quality issues. Land use has
non-structural solutions to these critical changed significantly and the plan should
programs and activities. consider planned development and
redevelopment activities. Stormwater quality
permitting requirements and BMPs should be
&XUUHQW3URJUDP(OHPHQWV
further assessed and applied to individual sub-
basins. The following issues should be
Current stormwater drainage program
considered:
elements include stormwater collection system
and planning; design and construction
Assess current and future land use and
standards; maintenance; detention and
associated imperviousness.
groundwater extraction and release.
Update hydrology/hydraulic models.
*XLGLQJ3ULQFLSOHV
Consider groundwater flows when
Guiding principles for the stormwater drainage
evaluating existing capacity.
program component based on national trends
and current local policies, are proposed as
Consider peak flows for the minor and
follows:
major storm events.
1.Maintain and Preserve Existing and
Limit the post development peak discharge
1DWXUDO'UDLQDJH6\VWHPVµ
rate to the pre-development discharge rate
for single design two-year storm events.
2.´5HGXFHDQG0DQDJH'HYHORSHG
5XQRIIµ
Separate stormwater drainage from the
irrigation ditches.
3.´(OLPLQDWH'UDLQDJH3UREOHPVDQG
1XLVDQFHVµ
Focus on known problem and future
development areas.
5HFRPPHQGHG6WRUPZDWHU'UDLQDJH
Integrate water quality and other multi-
3URJUDP(OHPHQWV
objective issues in the updated plan.
Stormwater Collection System and
Re-evaluate detention including the
possibility of regional detention and
Planning
increasing existing detention.
The existing Stormwater Collection System
Locate (estimate) the water table
Master Plan provides the City of Boulder with a
throughout the City.
guide for minor storm (2-year frequency for
ES-8
Re-evaluate remaining projects for Remove debris from inlets on a 2-year
necessity and community objectives. cycle or as needed based on requests.
Re-prioritize recommended projects. Remove silt and sand deposits from
manholes and open channels on a 2-year
5HYLHZDQGUHYLVHWKH&LW\·VFULWHULDIRU
cycle or as needed based on requests.
prioritization.
Inspect and repair storm sewer pipe on a
2-year cycle or as needed based on
Design and Construction Standards
requests.
The City's Design and Construction Standards
Clean excessive deposits of sediment
(DCS) regulate the design and construction of
within storm sewers on a 2-year cycle or as
public infrastructure, improvements, and
needed based on requests.
landscaping within the City's public rights-of-
way and public easements. The current
Detention
standards were last updated November 16,
2000, and need to be consistent with the most
The City has required on-site detention for new
current versions of the Urban Drainage and
developments since the early 1970s. On-site
Flood Control District (UDFCD) standards.
detention storage is required for all
Stormwater drainage and stormwater quality
developments other than individual single-
standards also need to be integrated.
family lots that are not part of a larger
development. Most of these facilities are
Maintenance
privately owned and maintained. The design of
these facilities is reviewed by City staff at the
The recommended action items will address
time of application. The facilities are inspected
the current maintenance issues of frequency
and as-built drawings are now required to be
and tracking of maintenance activities.
submitted. However, there is currently no
follow-up City inspection to assure these
Integrate above grade facility information
facilities are functioning as originally intended.
associated with the major drainageways
LQWRWKH&LW\·VPDLQWHQDQFHPDQDJHPHQW
Recommendations for on-site detention
system.
include:
Integrate maintenance performed by the
Review each development plan to look for
8')&'LQWRWKH&LW\·VPDLQWHQDQFH
opportunities to increase detention greater
management system.
than the minimum currently required.
Include project management personnel in
Integrate water quality BMPs into on-site
the Call-Log database.
detention requirements.
Inspect and remove excessive vegetation
The amount of detention should be based
and debris along open drainageways on a
on the degree of redevelopment proposed
yearly cycle or as needed based on
requests.
ES-9
or an incentive plan, where going above
If the City believes or knows of a problem
and beyond decreases fees.
area, then a mitigation plan should be
required prior to permitting.
Recommendations for existing detention
facilities include:
If groundwater is not expected but is
encountered during construction then a
Determine if additional inspection and
mitigation plan should be required prior to
maintenance is needed based on the
issuing the certificate of occupancy.
condition assessment of a random
sampling of the existing facilities. On-
Evaluate the implications of groundwater
going inspection and maintenance could
contamination and further explore existing
be accomplished by either the City or
available soils information.
private property owners.
Consider groundwater discharge as part of
Require property owners to periodically
the update to the Stormwater Collection
submit an inspection report to the City
System Master Plan.
once every 5 years to certify that the
detention facility is functioning as originally
Identify problem areas and issues including
designed or there is a plan for
the effect of groundwater de-watering on
improvements.
local water wells and wetlands.
Groundwater
Develop mitigation options for specific
problem areas based on estimates of
Groundwater and sump systems create
additional groundwater flow.
nuisance drainage in the public rights-of-way
and potential hazards due to build-up of slime
and ice. Also, groundwater de-watering
PI
ROGRAM NTEGRATION AND
systems can affect local water wells and
IO
MPLEMENTATION PPORTUNITIES
wetlands by lowering the groundwater table.
Requirements for groundwater extraction and
The Stormwater and Flood Management Utility
release are loosely defined in current City
LVSDUWRIWKH&LW\·V3XEOLF:RUNV'HSDUWPHQW
regulations.
The organizational structure of the Department
provides both opportunities for and challenges
The recommended action items will allow for a
to integrating various program interests and
proactive, rather than reactive, approach to
other multi-objectives.
dealing with groundwater issues:
&XUUHQW3URJUDP(OHPHQWV
Identify problem areas and require more
The following institutional opportunities for
precise water table information that
integration are currently defined:
considers seasonal fluctuations.
Annual Budget Process
ES-10
Greenways Master Plan and Program Annual Budget Process
A significant opportunity for integration with
Project Planning and Approval Process
other City objectives is the 2005 update to the
(PPAP)
Boulder Valley Comprehensive Plan. The
update process will provide an opportunity to
Community and Environmental Assessment
review land use and zoning designations from
Process (CEAP)
the perspective of flood hazard, water quality
and drainage issues.
Design and Construction Standards (DCS)
A Flood Management Program office will be
5HFRPPHQGDWLRQVestablished to enhance and integrate various
program functions and provide a more
Program Integration focused point of contact for other staff and the
public. This office will work closely with
Planning and Development Services -
This master plan recommends maintaining
Floodplain and Wetland Management, which
existing coordination and integration
will continue to be the focal point for
processes. In addition to these existing
interactions with the development community.
processes for program integration, this master
plan has identified additional opportunities for
In addition it is recommended that the
coordination:
Greenways program be expanded to all 15 of
WKH&LW\·VPDMRUGUDLQDJHZD\VWRSURYLGHIRU
Board and Council Review and Discussion
better integration of multiple objectives.
of CFS Utility Master Plan
These additional opportunities provide a way
Interactive Web Site
to integrate various program interests and
other multi-objectives.
Stormwater Management Plan
Major Drainageway Planning
Program Implementation
Design and Construction Standards
To assure integration with various program
interests and other multi-objectives the City will
Flood Management Program
use a multi-disciplined approach and involve
staff from appropriate workgroups.
Greenways Program (including update to
Greenways Design Guidelines)
FC
INANCIAL ONSIDERATIONS
Boulder Valley Comprehensive Plan
The Utility is an enterprise funded primarily by
monthly utility fees. The Utility today receives
Water Quality Master Plan
annual revenues of over $4 million that are
applied to operating activities, emergency
Maintenance Program
ES-11
preparedness, stormwater quality, stormwater plan considers evolving regulations,
technology and development characteristics. A
maintenance and capital improvements.
slower, methodical approach will allow for
In general, existing programs are adequately
planning and adapting to these anticipated
funded. However, several increases to existing
changes.
program funding are presented. To support
these increases in funding, money will need to
be reallocated from the existing budget or a
rate increase will be required as follows. The
following proposed financial plan will be
FRQVLGHUHGDVSDUWRIWKH&LW\·VRQJRLQJ
budget process.
)ORRG0DQDJHPHQW
It is proposed that annual funding for the on-
going flood management program increased
from $100,000 to $350,000 per year. This
represents a shift to balance structural and
non-structural solutions for flood management.
6WRUPZDWHU0DQDJHPHQW
It is proposed that:
A one-time additional funding allocation of
$250,000 should be made in the 2005
budget to update the Stormwater
Collection System Master Plan.
Additional annual funding of $50,000
should be allocated to begin an inspection
and maintenance program for stormwater
quality and existing private on-site
detention facilities.
Additional annual funding of $50,000
should be allocated to GIS tools
development and support.
At proposed funding levels it will take many
years to achieve the goals of this master plan.
The financial approach recommended in this
ES-12
ATTACHMENT B
FLOOD CONTROL AND DRAINAGE UTILITY
PROJECT EXPENDITURES (1990-2012)
2013 Dollars
TOTALPERCENT
Property Acquisition
$15,636,477
Pre-Flood Acquisitions
$1,734,187
Branding Iron Mobile Home Park
$2,824,039
Boulder Creek Property Acquisition
$2,387,096
Mapleton Mobile Home Park
$3,297,809
Fowler Property Acquisition
$1,898,474
Tebo Property Acquisition
$480,700
Crouch Property Acquisition
Subtotal Property Acquisition$28,258,78135%
Major Drainageway Improvements
$22,757,526
Goose Creek
$1,105,715
Bear Canyon Creek through Martin Park
$1,272,530
Gregory Canyon Creek Drainageway
$8,267,750
Elmer's Two-Mile Creek
$475,356
Wonderland Creek-Valmont to Goose Creek
$380,886
Wonderland Creek at Boulder White Rock Ditch
$1,195,750
Wonderland Creek- Diagonal Highway
$380,968
Bear Creek Arapahoe to Foothills
$578,104
Bear Canyon Broadway Grd Sep
$756,823
Boulder Creek / Broadway Bridge
$2,082,780
South Boulder Creek Improvements
$329,226
Accelerated Tributary Projects
$1,600,653
Four Mile Creek
Subtotal Major Drainageway Improvements$41,184,06651%
Subtotal Storm Sewers$11,244,18714%
Total$80,687,035100%
Coot
Lake
Boulder Reservoir
Sixmile
Reservoir
Wonderland
Lake
Hayden
Lake
KOA
Valmont Reservoir
Lake
Leggett
Owen
Reservoir
Hillcrest Lake
Sombrero
Marsh
Baseline Rd
Baseline
Reservoir
Viele
Lake
Legend
Drainageways
Main Roads
Streets
Lakes
Boulder Boundary
City Of Boulder
01230.5
Miles
Major Drainageways
Figure 3-1
Executive Summary
The original 1984 City of Boulder Storm Water Collection System Master Plan is being updated
to reflect changes in land use, infrastructure and the regulatory climate as well as anticipated
redevelopment within the community. The revised Stormwater Master Plan (SMP) provides the
City of Boulder with the necessary planning tools and capital improvement projects to address
flood management and water quality within the collector portion of the storm drainage system
for the next decade.
The Boulder SMP was developed to replace the 1984 plan with a document that is more inline
with present-day problems and opportunities and the City’s overarching environmental,
economic and social goals. The goal of the Boulder SMP is to proactively manage stormwater
runoff to protect water quality and to minimize impacts of localized and downstream flooding by
identifying infrastructure improvements for the collection, conveyance and treatment of
stormwater runoff from within the City. The SMP prioritizes storm drain and water quality
improvements within the City and provides an implementation plan for the construction of
conveyance and water quality improvements
Major activities undertaken in the development of the plan include the following:
Develop system analysis and problem identification criteria,
Develop hydrologic, hydraulic and water quality models,
Evaluate the system and rank problem areas,
Perform alternatives analysis and develop a recommended plan,
Prepare a capital improvement plan.
Study Area Characterization
The City of Boulder, with a population of approximately 100,000 and an area of nearly 25.5
square miles, is locatedalong the front range of the Rocky Mountains, northwest of Denver,
Colorado. Within the City, there are 12 subbasin and 15 major creeks (a.k.a. major
drainageways) that generally flow from west to east as they converge on Boulder Creek, which
is the main tributary flowing through the City. Runoff from within the City is conveyed to these
major drainageways by the City’s collector storm drain system and the irrigation canal system.
At present, Boulder is nearly fully built-out withmuch of the future development expected to
occur as site redevelopment. Collectively, the current impervious percentage, assuming 2006
land use conditions,is 32% and is projected to be 34% under the Boulder Valley
Comprehensive Plan. However, considering the City’s Design and Construction Standards
(DCS), the net future condition imperviousness used for this analysis was determined to be
33%,
Planning and Analysis Criteria
A master planning analysis was performed to identify potential collector system stormwater and
associatedwater quality improvements within the City of Boulder. The evaluation was guided
by a set of system analysis criteria used to identify conveyance and water quality problem areas
and to evaluate potential improvements. These criteria included quantitative assessments of
storm drain surcharging, culvert overtopping, channel/canal flooding, structure flooding
(buildings, etc) and pollutant loadings. Other system analysis criteria used to support the study
1
included design storms (2-year, 5-year and water quality), landuse (existing and future
conditions)and model boundary conditions.
Analysis Approach
A key element in the master planning process is the development of a hydrologic, hydraulic and
water quality model of the natural and man-madestormwater system within the City. The model
should be capable of analyzing runoff conditions; predicting flooding risk; estimating
comparative pollutant loadings; evaluating existing facilitiesand infrastructure; and designing
proposed improvements. To these ends, the primary objectives of the stormwater analysis were
to:
Construct a model that accurately represents the existing stormwater system within the
City’s collector system.
Validate the model to previous studies and regional rainfall-runoff statistics.
Utilize a land use-based method to estimate runoff under current conditions and incorporate
the Boulder Valley Comprehensive Plan to represent future development conditionswithin
the City.
Evaluate the existing stormwater infrastructure with respect to the system analysis criteria
and rank each problem in terms of severity.
Locate, size and assess the performance of new stormwater management facilities
including pipes, detention ponds, surface channel and irrigation canals.
Locate, size and assess the performance of new water quality facilities based on areas
identified in the model that exhibit elevated pollutant concentrations and/or loads.
Limits of Analysis
The focus of the Boulder SMP is the collector storm drainage system, which includespipe 18” in
diameter and larger and primary open channel systems that are not part of the City’s major
drainageways. To further refine the stormwater conveyance system, two levels of service are
provided based on landuse and roadway category. For areas that are mainly residential in land
use, the 2-year recurrence interval design storm was used to identify problems in the
downstream conveyance system. For areas draining mainly commercial, industrial and collector
and arterial roadways, the 5-year event was used. Areas within the city that experience
localized flooding (e.g., undersizedpipes that are less than 18 inches in diameter; roadside
ditches; and clogged catch basins) were not considered as part of this study unless they have
been identified by the City as known flooding locations.
Modeling Approach
The modeling approach for the Boulder SMP integrated GIS as a pre- and post-processing tool
with an EPA-based Storm Water Management Model (SWMM) as the hydrologic, hydraulic and
water quality analysis tool. The analysis software used for the project was XPSWMM which is a
proprietary version of EPA-SWMM software that provided an efficient GIS interface that EPA-
SWMM does not have at this date.Workflow began in GIS, where the input parameters for the
SWMM model were developed. This data was transferred out of GIS to SWMM, for the
evaluation of the system hydraulics and water quality. Model results were ultimately brought
back into GIS for post processing and storage for future reference by the City.
Landuse and CityDevelopment Criteria
Land use is a key factor in assessing stormwater runoff because it affectsboth the quantity
(volume and peak) and quality of water being routed through the stormwater system and natural
channels. The effect land use has on water quantity can be generally linked to the amount of
2
impervious area for a particular land use category. The more impervious the area, the faster the
water will be routed to the storm water collection system due to the lower surface roughness of
the ground. It will also have an increase in volume since infiltration can not occur through
impervious surfaces. Consequently, an area with a higher percentage of impervious surfaces
will produce higher peak flows over a shorter period of time than will a similar area with a lower
percentageof impervious surfaces.
The future conditions scenario represents a fully developed urban area according to the Boulder
Valley Comprehensive Plan, 2006 (BVCP). This scenario represents a worst case scenario
from a stormwater perspective because it encompasses the highest level of imperviousness.
However, this scenario has also incorporated the City’s DCS, which require detention and water
quality treatment for all new impervious areas associated with new and re-development
projects. As discussed in later sections of this report, the City performed an inventory of
existing detention and treatment facilities and it was identified that roughly 78% of all current
facilities are adequately functioning (22% have failed). Consequently, to incorporate the DCS,
this same facility performance level (78%) was also assumed to occur under future development
conditions.To accomplish this, thechange in impervious percentage between existing and
future conditions was reduced by 78% to account for the detention and treatment facilities that
will collectively be built as the city develops and/or re-develops.
Problem Identification
Utilizing the verified SWMM model, runoff, hydraulic, and water quality calculations were
completed for two different land use scenarios: existing conditions and future conditions, and
three different design storms: the 2- and 5-yr events and the water quality storm. These results
were then evaluated with respect the previously noted system analysis criteria to identify
specific system deficiencies within the City’s collector storm drain system.
Hydraulic Problem Areas and Ranking
Model results for existing conditions indicate that 572 nodes out of 1635 nodes within the model
violate one or more of the noted criteria. To better understand the cause and affect of each
problem area, a number of these deficient nodes and links were combined together into
individual problem locations. This resulted in a total of 51 hydraulic problem locations. Irrigation
canal segments were also added to the problem identification list if the correspondingdesign
storm causes the channel to overtop its banks and flood the surroundingarea.
Due to the relatively large number of problem locations identified through the modeling and GIS
analysis, and due to limitations within the City’s capital budget, a ranking was performed on the
problem areas to prioritize the conveyance problems. This process resulted in identifying three
problem priority levels; Tier 1, Tier 2 and Tier 3 indicatingsevere, major or minor problem areas,
respectively. The process of ranking system problems into tiers utilized a point-basedmatrix
using a weighted criteria approach.Six criteria were used to rank the problem areas. These
criteria include: 1) the extent of the problem, 2) the flooded volume, 3) the impact to neighboring
structures, 4) the length of under capacity pipe, 5) the confidence in the underlying data and 6)
the proximately of the hydraulic problem to waterquality areas of concern. The problem
prioritization process resulted in five Tier 1 problem areas, 17 Tier 2 problem areas, and 31 Tier
3 problem areas. These problem locations are shown on Figure ES-1.
Water Quality Analysisand Problem Areas
The water quality analysis included two separate approaches to identify problem locations within
the collector system: 1) a buildup-washoff analysis using the XPSWMMmodel to identify water
quality areas of concern that produce high pollutant loads and 2) targeted outfall approach
focusing on the collector system outfalls to Boulder Creek. The water quality area of concern
3
approach used the XPSWMMmodel to identify areas within the City having comparatively
higher pollutant concentrations and/or loads. This approach identified 12 locations within the
City that were characterized as water quality areas of concern. The Boulder Creek outfall
approach identified 17 collector system outfalls that do not currently receive pollution reduction
through regional water quality facilities. The water quality areas of concern and Boulder Creek
outfall sites are shown on Figure ES-2.
System Improvement Alternatives and Recommendations
Improvement alternatives were developed for the Tier 1 and Tier 2 problem areas and a
qualitative assessment identified the preferred alternative for each problem area. The Tier 3
problem areas did not receive an evaluation of different alternatives due to the limited severity of
the conveyance problems. Instead, improvements to resolve the Tier 3 problem areas consisted
of pipe replacement to increase the system capacity and resolve the conveyance problem.
For the water quality area of concern sites, improvement alternatives were developed to
evaluate the optimum improvement for a give site or location. Improvements for the Boulder
Creek outfall sites were developed based on the use of proprietary BMPs (a.k.a. water quality
manholes) since these types of facilities are best suited for highly urbanized areas as typically
found near the collector system outfall top Boulder Creek. A cost/benefit analysis was
performed for the improvement water quality improvementsat each of the water quality area of
concern and Boulder Creek outfall sites. This process identified 18 water quality improvement
projects to address the address the water quality area of concern site and the Boulder Creek
outfall sites that favorable cost/benefit ratios or that did not rely on future development for
project implementation.
The recommended plan for addressing the conveyance and water quality problem areas is a
compilationof all hydraulic and water quality improvements developed in this study.Figure ES-
3 provides an overview of the recommended plan improvements with corresponding
improvement projects IDs. In some instances, the recommended water quality improvements
were in close proximity to a hydraulic improvement location and were combined into a single
project. Other recommended improvements consist of improvements that separately address
water quality or conveyance problems.
Capital Improvement Plan
The goal for this master plan is to manage stormwater, by minimizing impacts on localized and
downstream flooding and improving water quality. To these ends, the recommended system
improvements were categorized as 1) Hydraulic and Combined Hydraulic/Water Quality projects
or 2) Water Quality Improvement projects. These two project categories form the collector
system Capital Improvement Plan (CIP).
The implementation plan for the Hydraulic and Combined Hydraulic/Water Quality CIP projects
follows the Tier 1, 2 and 3 problem areas. Tier1 CIP projects are considered high priority
improvements as they resolve severe conveyance system problems and in some instances
address stormwater quality problems. Tier 1 projects areas are anticipated to a) have a high
social benefit by resolving street and property flooding issues,b) have a high economic benefit
by reducing flooding risk and property damage, and c) provide an environmental benefit by
addressingstormwaterquality issues at identified problem locations. Note that not all Tier 1
locations included a water quality problem site and that the overriding criterion for prioritization
was resolving flooding issues. Table ES-1 identifies the Tier 1 CIP projects; Tier 2 and 3
projects are identified in Sections 5 and 6 of the main report.
4
Table ES-1: Tier 1 Hydraulic and Combined Hydraulic/WaterQuality CIP Projects
RankingImprovementLocationImprovement TypeCapital
IDCost
$10,701,000
1GC_02Upper Goose CreekPipe Replacement
New Storm Drain
Channel Improvement
$1,577,000
th
2MBC_1018 and Spruce Street Pipe Replacement
Storm Drain Re-Routing/Extension
$1,659,000
th
3MBC_14Arapahoe and 28Pipe Replacement
Street
Storm Drain Re-Routing/Extension
Proprietary BMP
$5,694,000
4DC_01Gunbarrel–SpinePipe Replacement
rd
Road, Lookout and 63
Storm Drain Re-Routing/Extension
Systems
Constructed Wetland
The implementation plan for the Water Quality Improvement (WQIMP) projects were prioritized
based on problem severity as identified by pollutant load. The WQIMP category was developed
since many of the water quality project sites were not adjacent to hydraulic problem and
improvement locations.In addition, many of these WQIMP projects could be defined as a small
capital projects since the estimated construction costs are less than $100,000.
Table ES-2: Water QualityImprovement CIP Projects
Location
ImprovementAnnualCapital
IDTSSCost
Load
(pounds)
$104,000
61,900 th
WQIMP 2 Boulder Creek 1,400’ East of 75 Street
$81,000
th
56,500
WQIMP 3 Boulder Creek & 28 Street
$76,000
th
WQIMP 5 46,200Boulder Creek & 75 Street
$157,000
WQIMP 6 & 45,700Boulder Creek & East Broadway Street & Arapahoe
WQIMP 9 & 38,400Avenue
WQIMP 8 $84,000
41,500Boulder Creek 200’ West of Folsom Street
WQIMP 12 $78,000
29,000Boulder Creek & Folsom Street
WQIMP 14 $73,000
24,200 th
Boulder Creek & 9 Street
WQIMP 15 $73,000
22,800
Broadway & Skunk Creek
WQIMP 16 $81,000
20,300 th
Boulder Creek & 13 Street
WQIMP 18 $51,000
th
15,000Boulder Creek & 11 Street
Estimates of capital construction costs included in this plan are considered planning level
estimates to be used in developing stormwater capital budget requirements.
5
Attachment G
100-Year Event Flood Mitigation Costs
Historic 100-year Flood Mitigation Costs
Design
Actual Total
Flow
Channel ImprovementsCost (2013 Lineal Feet
Rate
dollars)
(cfs)
Elmers Two Mile Creek8,260,243$
2500900
Goose Creek22,401,809$
35003000
Design
Actual Total
Roadway
Flow
UnderpassesCost (2013
Lanes
Rate
dollars)
(cfs)
Wonderland-Diagonal Underpass2,537,987$
62200
Broadway/Skunk Creek Grade Seperation1,503,495$
61350
Ballpark Estimated 100-year Flood Mitigation Costs
Design
Flow
Channel ImprovementsLineal Feet
Total Estimated
Rate
Cost
(cfs)
Fourmile Canyon Creek
Violet to 28th St.$35-45 million6,000 3,600
Twomile Canyon Creek
Linden to Broadway$15-20 million4,000 1,000
Sunshine Canyon Creek
Mapleton to Canyon$5-10 million2,000 1,000
Gregory Canyon Creek
Flagstaff to Boulder Creek$30-35 million6,000 1,800
Bluebell Canyon Creek
12th St. to Sunnyside Lane$10-15 million3,500 700
Upper Goose Creek
Broadway to Folsom$40-50 million7,500 1,600
Wonderland Creek
19th St. to 26th St.$15-25 million5,000 1,000
South Boulder Creek
West Valley Overflow Mitigation$35-40 million
Boulder Creek
Foothills Parkway to Eben Fine Park$100-200 million11,000 12,000
Total
$300-400 million