Western Washington Hydrology Model Version 3 Vancouver, WA, Workshop October 17, 2007 PM

Western Washington Western Washington Hydrology ModelHydrology Model

Version 3Version 3

Vancouver, WA, Workshop

October 17, 2007 PMOctober 17, 2007 PM

WWHM3 Advanced Features

1. offsite basin2. bypass basin3. sand filter4. lateral flow basins5. gravel trench bed/porous pavement6. bioretention/rain gardens (PRO)7. green roofs (PRO)8. culverts/HY8 (PRO)9. time series10. criteria checker (PRO)11. water tags (PRO)12. LID Analysis Tool13. Summary Report (PRO)14. Your topics of interest?

Offsite Basin

An offsite basin is a basin outside the project basin that drains through the project site to the project mitigation pond.

Bypass Basin

A bypass basin is a basin that is in the project site, but does not drain to the project mitigation pond.

Sand Filter

A sand filter is a water quality facility that is required to filter 91% of the total runoff volume.

LID Modeling

• Lateral flow basins/Impervious runoff dispersion.

• Rain gardens.

• Green roofs.

• Porous pavement.

Impervious Runoff Dispersion Modeling

Dispersion of impervious roof runoff on adjacent pervious lawn allowing some water to infiltrate before becoming stormwater runoff.

Lateral Flow Basins

Lateral flow basins allow the lateral flow from an impervious drainage basin to flow across a pervious drainage basin. Total runoff is reduced.

Bioretention/Rain Gardens

Rain garden/bioretention/landscape swale

Water infiltrates into the soil before runoff.

Bioretention/Rain Gardens

Bioretention swale/rain garden is a stormwater mitigation facility. It stores and infiltrates runoff.

Green Roof Modeling

Green/vegetated/eco-roof

Water is stored in the soil prior to runoff.

Green Roofs

Green roof (also called a eco-roof or vegetated roof) is a stormwater mitigation facility on the roof of a building.

Porous Pavement Modeling

Currently represented by the gravel trench bed element.

Gravel Trench Bed/Porous Pavement

Gravel trench bed is a stormwater mitigation facility; it can also be used to represent porous pavement.

Other WWHM3 Features

• Culverts / HY8 program

• Time series

• Criteria checker

• Water tags

• LID Analysis Tool

• Summary Report

Culverts/HY8

Culverts are conveyance facilities. The Federal Highway Administration HY8 program can be used to define the culvert’s hydraulics (optional).

Time Series

Time series is a flow or precip period of record from another WDM to be used as input to the project.

Criteria Checker

Criteria checker checks to set if certain user-defined flow criteria are exceeded at a specified POC.

Water Tags

Water tags are used to track the movement of water from a specific source through the conveyance system.

LID Analysis ToolLID Analysis Tool compares different development options selected by the user and shows the runoff distribution.

Summary ReportSummary Report provides a detailed summary of the project input information.

WWHM3 packages

• WWHM3 Standard: free from Ecology.

• WWHM3 PRO: available for a fee from CCS.• PRO Basic: Includes culverts, bioretention/rain gardens, green/eco-roofs, criteria checker, multiple time steps, water tags, the ability to read HSPF UCI files, and the Summary Report option.• PRO GIS: Includes GIS Import and PRO Basic features.• PRO SWMM: Includes optional SWMM routing and PRO Basic features.• PRO Complete: Includes optional SWMM routing and GIS Import and PRO Basic features.

Questions?

Contact:

Doug Beyerlein 425.892.6454beyerlein@clearcreeksolutions.com

Joe Brascher 360.236.1321brascher@clearcreeksolutions.com