western washington hydrology model version 3 awra washington section january 2007 doug beyerlein,...

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,

2007.2007.

© 2007 Clear Creek Solutions, Inc.© 2007 Clear Creek Solutions, Inc.

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


Ecology’s Stormwater Management Manual

Specifies a flow duration standard

Requires the use of Western Washington Hydrology Model (WWHM) or equivalent


Flow duration standard: based on erosive flows.

Erosive flow range: ½ of the 2-year to the 50-year


Flow Duration Analysis: Percent of time the flow exceeds a specific value.

Requires continuous simulation hydrology to compute flow duration.


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

WWHM Rain Garden ModelingSeattle Bioretention Swales

WWHM Rain Garden Modeling

Native Soil

Native Soil

Native Soil

Amended Soil (1-3 layers)

Weir and vertical orifice outlet

Underdrain (optional)

Rain Garden ModelingSeattle Rain Garden Frequency Reduction

Return Period (years) Reduction

2 66%

5 63%

10 64%

25 66%

50 67%

100 69%

WWHM Rain Garden ModelingStormwater volume reduction:

Stormwater Reduction (%) for Seattle Soils

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

0% 5% 10% 15% 20% 25% 30% 35% 40% 45% 50%

Ratio of Rain Garden Area to Impervious Area

Re

du

cti

on

Till Outwash

Applications in Other Applications in Other Regions of the CountyRegions of the County

Bay Area Hydrology Model (BAHM), CaliforniaBay Area Hydrology Model (BAHM), California

Edwards Aquifer Hydrology Model, TexasEdwards Aquifer Hydrology Model, Texas

Bay Area Bay Area Hydrology ModelHydrology Model

Developed for:Developed for:

Alameda Countywide Clean Water ProgramAlameda Countywide Clean Water Program

Santa Clara Valley Urban Runoff Pollution Prevention Santa Clara Valley Urban Runoff Pollution Prevention ProgramProgram

San Mateo Countywide Stormwater Pollution Prevention San Mateo Countywide Stormwater Pollution Prevention ProgramProgram

BAHM

Residential development:

BAHM – WWHM Differences:

Flow control standard: BAHM: 10% of 2-yr to 10-yrWWHM: 50% of 2-yr to 50-yr

Pre-development standard: BAHM: existing land useWWHM: forest

Water quality standard: BAHM: 48-hr retentionWWHM: 91% treatment

Edwards Aquifer:Major water supply for San Antonio-Austin, TX

Watersheds: Blanco Frio-Dry Frio Sabinal Sabinal-Medina Medina Medina-Cibolo Cibolo Guadalupe Nueces

Edwards AquiferWatershed Topography

Edwards AquiferSabinal watershed:

Compute recharge (based on 50-year historic precipitation record)

Edwards Aquifer

Evaluate changes in annual recharge:

Edwards AquiferEvaluate:

Vegetation management impacts Precipitation augmentation Additional in-stream recharge

structures

Software to be completed in 2007.

Acknowledgements

Seattle Public Utilities and Washington State University provided the funding for this modeling of green roofs and rain gardens.

The City of Portland, Oregon, Bureau of Environmental Services (BES) provided the Hamilton green roof monitoring data.

WWHM Future Enhancements

additional low impact development/ source BMPs

HSPF water quality 3-D graphical interface your ideas?

WWHM3Questions?

Contact:

Doug Beyerlein [email protected]

Joe Brascher [email protected]

Or go to: www.clearcreeksolutions.com

western washington hydrology model version 3 awra washington section january 2007 doug beyerlein,...

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