5 - Presentation: Update on the Stormwater Strategic PlanWilllams - Pubic Works Director for
• Bob Harberg - Utilities and Project Planning
CooMlnator
• Douglas Sullivan - Utilities Project Manager
• Jeff Arthur - Engineering Review Manager
• Qonna Scott - Water Quality Specialist
• Brett Hill - Information Resources GIS
Specialist
• Rich Thornton - HDR Project Manager
• Update to the Stormwater Collection
System Master Plan (1984)
• Recommended in CFS Master Plan
• Updated hydrology
^ Changes in land use
^ Improved data and analysis tools
• Community redevelopment
~ Water Quality
• Flood Management
• Major Drainageways
• Property Acquisition
• Stormwater Quality
^ WQ regulations
• Stream enhancement
• Stormwater Drainas~e
• 2-year and 5-yr storms
^ Nuisance flooding
• Identlfied 57 potential CIP projects
totaling $15,000,000
• ProJects were categorized in four
priority le~els (A through D)
^ Prio~ity A=10 projects - 5 constructed
• Priority B= 8 projecta - 3 constructed
• Priority C= 26 projects - 3 constructed
^ Priority D -13 projects -1 constructed
• Major Drainageway Improvements
• 12 maJor dralnageways tributary to Boulder
Creek
• Provide 1D0-year storm conveyance
^ Goose Creek, Bear Creek, S. Boulder Creek,
Wonderland Creek, Four-Mile Canyon Creek
Property Acquisitlon
• Focua on life and safety issues
• Remove structures irom High Hazard Zone
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• Major Drainageways = $16.1 M (35%)
• Property Acquisition = $20.7M (45%)
• Storm Sewers = $4.5M (10%)
• Greenways = $2.7M (6%)
r Miscellaneous = $1.6M (4%)
~ Total = $45.6M
• CIP = $2~2.5 miliion/year
^ Storm Sewer Funding
• 3300,OOOtyear (2007 - 2010)
• 5800,OOOtyear (2071 & 2012)
• Builds upon the CFS Master Plan
^ "Maintain and preserve existing and
natural drainage systems"
^ "Reduce and manage developed runoff'
^ "Eliminate drainage problems and
nuisances"
3
• Stormwater Drainage Program
Elements
• Stormwater Collection System Planning
^ Design 8~ Construction Standards
^ Maintenance
^ Detention
• Groundwater
• City wide analysis of the Collector
Storm Sewer System
• Identifies system improvements
necessary to maintain the level of
service required by the DCS.
• Focuses on minor rainfall events
• Storm Sewer Conveyance
^ 2-year and 5-year storms
• Starmwater ~luality - What is it?
• Addressed pollutant conveyed to the
creeks via storm runoff
^ Water quality storm ~ flushing event
~ Stormwater Quality - Why is it
Important?
^ Regulatlons - City's NPDES permit
^ Recreational use
Aquatic and riparian habitat
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• Data Collection
• Model Development
• Subbasin Characterization
• Alternatives Analysis
• Capital Improvements Plan (CIP)
~ Population = approx. 100,000
• Service area = approx 25 square miles
• Drainageways = 15 Creeks
~ Miles of Storm sewer = 52 miles
^ 18" diameter and larger pipe
• Impervious Area = approx. 32%
• Runoffwithin .-..~-
Subbasins is ~ '-" -
conveyed to the ~''"~ u
MaJor Drainageways ~r; ~ "
~_
via the Collector 1,.`,~x .. ~ ~ '
system and overland ; , "
flow. 4;,~. r
5
• Primary variable in
starmwater runoff
• SSP used actual
measured values
from City's aerial
photography
• Prioritization Criteria
• Problem Extent
^ Flaoded Volume
^ Structure Impact
^ Length of High (ar,ro
^ Data Confidence
^ Water Quality
~ Study identified 55 potential
conveyance and water quality problems
• Hydraulic and water quality problems
were integrated when located in the
same vicinity
~ Study identified 12 Water Quality Areas
of Concern
6
• Nydraulic Problems
^ 4, Tier 1 problems ~
Major (Red)
^ 17, Tier 2 problems ~
Moderate (Green)
• 34, Tier 3 problems ~
Nuisance (Blue)
° -•d r
_~~_ ~ ~.
~ ~, T ,
`~',~,~_.~. i-_
_ -~'.. ~
' ~ i- ~,j, ~,4..
-.-• ~~~-
_~~
~ SSP identlfied 12 Water Quality Areas
of Concern
^ Sites based on pollutant loading to creeks
• SSP also analyzed pollutant loading
from 18 Boulder Creek outfalls
• Malysis Approach _ ~ ' _ ~
• Identlfied hlgh pollutant i~ ~ -
1
~'
load areas (~: = T ~,
^ Targeted outfalls to "'='"';"'.
~ :
Boulder Creek - -~
~~:._.
• Results
~^ =~- '
• Identifled 12 Water
~ ~ `, `'
Quality Areas of =
Concern ~ ~ i
• Identifled 78 Boulder .
~
Greek Outfalls -
- -~- -
~ -
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Improvement types rF'_
• Comeyance ~
c~
• WaterqualKy 5~_
• Combined WQ + Conveyanca ,~.
Prlorltlzed Improvements `~` ~
• Hlgh, Moderate, Low ~-
High Prlorfty Improvements e
• Upper Goose Creek - 9th and ~~
:
Batsam
~:
~
• Broadway - Irfs to Balsam '. ~
• 18th and 5pruce/Pea~l
• Arapahoe and 28th
v-
~ Splne, Lookout, 8 83rd
(Gunbarrel) -
~ Tier 1 = $30,000,000
• Tfer 2 = $17,000,000
~ Tier 3 = $14,000,000
• WQ = 51,000,000
~ Total = $62,000,000
• Upper Goose Creek Drainage (9"' to 19~
Street)
^ Top Tier 1 Project
• Estimated cost = E15,000,000
• Construction in numerous phases
^ Begin downstream along Edgewood Drive
^ Impacts: N. Boulder Park, BCH, etc.
• Upper Goose Creek improvements
^ 2007-2009 = No funding
^ 2010 = $50,000
^ 2011 = $250,000
^ 2012 = 5250.000
^ Total = $550,000
Additional info for WRAB?
• Return to April WRAB meeting
^ Ask for recommendation adopting the
SSP
~ Work projects into 2008-2013 CIP
• Evaluate benefit cost of Tier 1
projects
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