Using GIS to Aid in TMDL Modeling

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)