Urban storm water runoff is being investigated as a nonpoint source of pollution across the country as urban areas with
populations over 100,000 conduct studies designed to meet U.S. Environmental Protection Agency guidelines for National
Pollutant Discharge Elimination System permits for their stormwater discharges. From 1991 through 1994, the City of
Davenport, Iowa (fig. 1), and the U.S. Geological Survey cooperatively conducted a study designed to meet technical
conditions of the permit application and to develop the criteria for ongoing monitoring during the term of the permit.