Western Washington Hydrology Model Version 3

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Western Washington Hydrology ModelVersion 3

• Vancouver, WA, Workshop
• October 17, 2007 PM

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WWHM3 Advanced Features

• offsite basin
• bypass basin
• sand filter
• lateral flow basins
• gravel trench bed/porous pavement
• bioretention/rain gardens (PRO)
• green roofs (PRO)
• culverts/HY8 (PRO)
• time series
• criteria checker (PRO)
• water tags (PRO)
• LID Analysis Tool
• Summary Report (PRO)
• Your topics of interest?

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Offsite Basin

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

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Bypass Basin

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

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Sand Filter

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

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LID Modeling

• Lateral flow basins/Impervious runoff
  dispersion.
• Rain gardens.
• Green roofs.
• Porous pavement.

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

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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.

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Bioretention/Rain Gardens
Rain garden/bioretention/landscape swale

Water infiltrates into the soil before runoff.
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Bioretention/Rain Gardens

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

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Green Roof Modeling
Green/vegetated/eco-roof

Water is stored in the soil prior to runoff.
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Green Roofs

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

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Porous Pavement Modeling

• Currently represented by the gravel trench bed
  element.

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Gravel Trench Bed/Porous Pavement

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

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Other WWHM3 Features

• Culverts / HY8 program
• Time series
• Criteria checker
• Water tags
• LID Analysis Tool
• Summary Report

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Culverts/HY8

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

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Time Series

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

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Criteria Checker

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

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Water Tags

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

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LID Analysis Tool

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

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

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Questions?Contact Doug Beyerlein
425.892.6454beyerlein_at_clearcreeksolutions.com
Joe Brascher 360.236.1321brascher_at_clearcreeksol
utions.com