TMDL Modeling Toolbox

Watershed Characterization System (WCS) and its Modeling Extensions Brian Watson Tetra Tech Inc.

TMDL Modeling Toolbox - WCS

What Is WCS?

• • Customization and enhancement of EPA BASINS for EPA Region 4 – Uses ESRI ArcView-GIS 3.x as a platform – Desktop system – Automated characterization report using spatial databases

Differences

between BASINS and WCS – At present, WCS uses only EPA region 4 data, but can be customized for any state – WCS supports various extensions such as Sediment tool, Mercury tool, SWMM, NPSM and LSPC – WCS does not support PLOAD and SWAT

TMDL Modeling Toolbox - WCS

WCS Uses

• Basic system (core) – Characterize watersheds – Evaluate water quality conditions – Assess potential sources of impairment • Enhanced system – Add Extensions which increase WCS capabilities • In general, WCS is a repository for watershed data and assessment tools to support TMDL and other environmental programs

TMDL Modeling Toolbox - WCS

WCS Characterization Reports

Tools Automated reports Maps and Tables Environmental Data

TMDL Modeling Toolbox - WCS

WCS Extensions

Core watershed data and assessment tools Extensions • • • •

Additional Menu functions Additional Datasets Additional System files Supported Models

TMDL Modeling Toolbox - WCS

WCS Extensions

Models

• Sediment tool • Mercury tool • SWMM model GIS interface • NSPM model GIS interface • LSPC model

Utilities

• NHD download tool • Manual and auto delineation watershed tool • WRDB extension

TMDL Modeling Toolbox - WCS

Sediment Tool – Overview •

Input

•

WCS Core + Sediment Tool

•

Output Land Use Soil Elevation Road Stream BMP

USLE Equation 4 Sediment Delivery Methods Transport Routing Algorithm Erosion Maps Sediment Delivery Maps Sediment Delivery to Assessment Points Automated Reports (Maps and Tables)

TMDL Modeling Toolbox - WCS Sample Results: BMP & Erosion - Little River Watershed K, GA

Before, no BMP, erosion = 1032 US tons.

Dark orange color indicates high Erosion.

After, applying a BMP to row crop areas, P = 0.65, erosion = 851 US tons, an 18% reduction.

BMP area

TMDL Modeling Toolbox - WCS

Mercury Tool: Overview

Algorithms in the WCS Mercury Extension

Land use and USLE parameters Delivery algorithms Sediment Yield Calculation Local climate, land use, and soil Hydrology algorithms Hydrology Calculation Dry + wet deposition Chemistry algorithms Soil Mercury Concentration Mercury Load • Deposition on water and impervious surfaces • Loads from runoff and sediment (pervious surfaces) • Loads from point sources

TMDL Modeling Toolbox - WCS

Mercury Tool: Sample Results Mercury Loading in Savannah River Basin

TMDL Modeling Toolbox - WCS

SWMM GIS Interface: Overview

WCS GIS + VB Interface + SWMM Model = WCS SWMM WCS GIS Interface VB Interface

Land use Stream Network Station Rainfall Data Output Visualization

PCSWMM

Input Text Editor SWMM Model (PCSWMM) Files.ini

Rainfall.dat

Runoff.dat

Transport.dat

TMDL Modeling Toolbox - WCS

SWMM GIS Interface: Link to PCSWMM • PCSWMM was developed by Computational Hydraulics International (http://www.chi.on.ca) • SWMM blocks (modules) are represented by graphic objects.

TMDL Modeling Toolbox - WCS

WCS-LSPC GIS Interface: Overview • WCS automatically prepares LSPC database (shapefiles and MS Access tables) for delineated watersheds.

• LSPC uses WCS prepared database to generate model input files.

WCS (ArcView GIS) LSPC (MapObjects and MS Access) One-way

TMDL Modeling Toolbox - WCS

Conclusions:

• WCS is an extremely versatile framework for environmental databases and models • WCS (and BASINS) can be customized to many different uses beyond just TMDLs

TMDL Modeling Toolbox - WCS

How to Obtain WCS and Its Extensions

WCS Web Site: http://wcs.tetratech-ffx.com

TMDL Modeling Toolbox - WCS

WCS Web Site WCS Web Site

TMDL Modeling Toolbox - WCS

WCS Web Site

Download WCS Documentation

TMDL Modeling Toolbox - WCS

WCS Web Site

Download WCS Data by Map or HUC

TMDL Modeling Toolbox - WCS

Demonstration of WCS Extensions

TN-WCS Extension • Will show how individual states can customize WCS (Tennessee Example) • Perform a simple watershed characterization with Tennessee specific datasets WCS to LSPC Extension • Use Flint Creek Watershed (Alabama) as example