Western Washington Western Washington Hydrology Model Hydrology Model Version 3 Version 3 AWRA Washington Section AWRA Washington Section January 2007 January 2007 Doug Beyerlein, P.E. Doug Beyerlein, P.E. Clear Creek Solutions, Inc. Clear Creek Solutions, Inc.
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Western Washington Hydrology Model Version 3 AWRA Washington Section January 2007 Doug Beyerlein, P.E. Clear Creek Solutions, Inc.
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Western Washington Western Washington Hydrology ModelHydrology Model
Version 3Version 3
AWRA Washington SectionAWRA Washington Section January 2007 January 2007
Doug Beyerlein, P.E. Doug Beyerlein, P.E.
Clear Creek Solutions, Inc.Clear Creek Solutions, Inc.
Western Washington Western Washington Hydrology ModelHydrology Model
Version 3Version 3
This presentation was given by Doug This presentation was given by Doug Beyerlein at the AWRA Washington Beyerlein at the AWRA Washington
Section meeting at Pyramid Ale House Section meeting at Pyramid Ale House restaurant in Seattle on January 24, restaurant in Seattle on January 24,
Clear Creek Solutions’ Clear Creek Solutions’ Hydrology ExpertiseHydrology Expertise
Clear Creek Solutions, Inc., provides complete range of hydrologic and stormwater modeling services.• Clear Creek specializes in continuous simulation hydrologic modeling.
• We have 30+ years of experience modeling complex hydrologic and stormwater problems.
• We created WWHM3 for Washington State Department of Ecology and are adapting it to model San Francisco Bay Area watersheds and facilities.
• We teach WWHM and HSPF workshops.
PresentationPresentation
IntroductionIntroduction
WWHM Background and Theory WWHM Background and Theory
WWHM and HSPFWWHM and HSPF
WWHM3 Standard and PROWWHM3 Standard and PRO
WWHM3 LID ModelingWWHM3 LID Modeling
Applications in Other Regions of the Applications in Other Regions of the CountryCountry
Questions & AnswersQuestions & Answers
WWHM Introduction
Developed for the State of Washington Department of Ecology.
Project Manager: Dr. Foroozan LabibDepartment of EcologyPO Box 47600Olympia, WA 98504-7600(360) 407-6439email: [email protected]
WWHM Introduction
Developed for the 19 counties of western Washington.
Part of Ecology’sStormwater ManagementManual
WWHM Introduction
WWHM3 Standard is available free from the Washington State Department of Ecology web site:
http://www.ecy.wa.gov/programs/wq/stormwater/
WWHM Background and Theory
Washington State Department of Ecology’s Stormwater Management Manual updated in 2005 to comply with:
Federal Clean Water Act (NPDES Phase I and II) Federal Endangered Species Act State Water Pollution Control Act
WWHM Background and Theory
Ecology’s Stormwater Management Manual
Specifies a flow duration standard
Requires the use of Western Washington Hydrology Model (WWHM) or equivalent
WWHM Background and Theory
Flow duration standard: based on erosive flows.
Erosive flow range: ½ of the 2-year to the 50-year
WWHM Background and Theory
Flow Duration Analysis: Percent of time the flow exceeds a specific value.
Requires continuous simulation hydrology to compute flow duration.
WWHM Background and Theory
Continuous simulation hydrology models the entire hydrologic cycle for multiple years.
Stormwater runoff = surface runoff + interflow.
Where the rain goes:Where the rain goes:
Fore
st
Imp
erv
iou
s
Evapotranspiration
0%
100%
Surface Runoff
InterflowInterflow
Groundwater/Base FlowGroundwater/Base Flow
Land use development
WWHM Capabilities
WWHM uses continuous simulation hydrology to compute stormwater runoff for both
predevelopment and post-development conditions.
Predevelopment Post-development
WWHM Capabilities
WWHM continuous simulation computations from HSPF (included in WWHM software).
HSPF runs in the background with calibrated parameter values and local meteorological data.
HSPF sponsored and funded by EPA and USGS.
How WWHM/HSPF works
Drainage areas are divided into pervious land segments based on soil, vegetation, and land slope and impervious land segments.
Pervious and impervious segments are linked to conveyance pathways (pipes, ditches, ponds, streams, rivers, lakes, etc.)
Historic rainfall and evaporation are used as input.
How WWHM/HSPF works
The entire water cycle is modeled on an hourly or shorter time step for multiple years.
The model computes changes in soil moisture, evapotranspiration, and runoff every time step.
Three types of runoff: surface runoff interflow groundwater/base flow
How WWHM works
Calibrated parameter values are built into WWHM (different calibrated parameter values are used for different climatic regions).
Local precipitation and evaporation data are included in WWHM.
How WWHM works
User locates project on county map, inputs pre- and post-development land use, and proposed mitigation measure(s).
Predevelopment and mitigated flows are compared at Point of Compliance (POC).
Mitigated flows are not allowed to exceed flow duration standards.
How WWHM works
User outputs report file and project file.
Output files can be submitted to the permitting agency for approval.
Permitting agency can load project file and rerun analysis, if needed.
Report file summarizes input data and output results.
How WWHM works
Guidance/help is provided by User Manual Training Workshops CCS Project Book* Tech Support*
* Go to www.clearcreeksolutions.com for more details.
WWHM Version 3:
Goal: give the user greater flexibility and options:
High groundwater element Lateral flow between basins More elements More output options New LID options
WWHM Version 3:
Version 3 projects have no drainage area size limitations: entire watersheds can be modeled.
Version 3 can be customized to local jurisdictions (e.g., City of Bellingham, City of Seattle)
WWHM3 Standard:14 elements:
1. basin2. trapezoidal pond3. tank4. lateral pervious basin (NEW)5. high groundwater/wetland (NEW)6. vault7. open channel (NEW)8. time series (NEW)9. lateral impervious basin (NEW)10. gravel trench bed (NEW)11. sand filter12. flow splitter (IMPROVED)13. irregular-shaped pond14. stage-storage-discharge table
WWHM3 PRO:
WWHM3 Standard plus: user selected time step (5 minutes to one hour) tagged flow routing additional elements
culverts green roofs landscape swales/bioretention/ rain gardens SWMM routing connection
GIS land use connection
WWHM3 PRO:
SWMM routing connection
WWHM3 PRO:
GIS connection
WWHM3 LID Modeling
Green/vegetated/eco-roof
WWHM Green Roof ModelingStudy performed for Seattle Public Utilities
Green roof modeled: Portland Hamilton Building
Data provided by Portland BES
WWHM Green Roof ModelingSeattle Green Roof Frequency Reduction
Return Period (years) Reduction
2 24%
5 20%
10 18%
25 16%
50 15%
100 15%
WWHM Green Roof ModelingSeattle Roof Flow Duration Comparison
Conventional RunoffGreen Roof Runoff
WWHM Green Roof ModelingSeattle Roof Peak Runoff Comparison