1. Using GIS to Aid in TMDL Modeling
Term Project Presentation
CE394K GIS in Water Resources
November 30, 2000
Tony Sarman

2. Objective To understand the Total Maximum Daily Load (TMDL) process
To see what abilities GIS has to aid in the development of TMDLs

3. Background Clean Water Act section 303(d)
Identification and rank waters with insufficient controls
Set TMDL
Implementation of the control measures
Effluent Limits
Best Management Practices (BMP)

4. Background
TMDL - “maximum amount of a pollutant that a water body can receive and still meet water quality standards.”
LC = WLA + LA + MOS

5. Basins 3.0
Better Assessment Science Integrating Point and Nonpoint Sources (BASINS)
Directly integrated within an ArcView GIS environment
Modeling Tools
QUAL2E
Soil and Water Assessment Tool (SWAT)
Generation and analysis of model simulation (GenScn)

6. QUAL2E One-dimensional, steady-state water quality model
Able to give concentrations along the length of a river
Predominantly point source

7. SWAT
Simulates hydrology, pesticide and nutrient cycling, bacteria transport, erosion, and sediment transport
Predict effects of land use management
Daily time step

8. GenScn Replaced NPSM Create, analyze, and compare simulation scenarios
Simulate the hydrologic and associated water quality processes on pervious and impervious land surfaces and in streams and well-mixed impoundments

9. Summary Still working with the program Fixed problems since v. 2.0
Raster Data – Require Spatial Analyst
May be possible to model lakes, bays, estuaries
Snow melt algorithm (degree-day)