The Wisconsin Department of Natural Resources reports that nonpoint source pollution from urban and agricultural sources is the most serious water quality problem in the state, degrading 90 percent of our inland lakes, 40 percent of our streams, and much of the coastal waters of the Great Lakes.  An important goal of this topic is the integration of GIS and nonpoint source pollution models to better understand and manage stormwater pollution.

Stormwater Management GIS Training
This site provides access to the GIS tools used to support an all-day workshop conducted by David Hart and Brea Lemke of the University of Wisconsin-Madison in March 2003 on GIS and  stormwater management. The tools include L-THIA (Long-Term Hydrologic Impact Assessment) developed by Purdue University; BASINS (Better Assessment Science Integrating Point and Nonpoint Sources) developed by the Environmental Protection Agency; ISAT (Impervious Surface Analysis Tool) developed by the NOAA Coastal Services Center; and SLAMM (Source Loading and Management Model) developed by Robert Pitt and John Voorhees.
http://coastal.lic.wisc.edu/stormwater/welcome.htm