Water-quality data of stormwater runoff from Davenport, Iowa, 1992 and 1994
The Water Quality Act of 1987 required the U.S. Environmental Protection Agency to regulate stormwater discharges under the National Pollutant Discharge Elimination System program, and guidelines for obtaining permits under this program were established for areas served by municipal separate storm sewer systems with populations greater than 100,000 (U.S. Environmental Protection Agency, 1992a, 1992b). The City of Davenport, Iowa, and the U.S. Geological Survey cooperatively conducted a study designed to meet technical conditions of the permit application and to develop criteria for ongoing monitoring during the term of the permit. During 1992 and 1994, stormwater runoff in Davenport, Iowa, was sampled from the following land use types: agricultural and vacant, residential, commercial, parks and wooded areas, and industrial. Grab samples collected within the first hour of the runoff event were analyzed for many constituents including volatile organic compounds. Flow-weighted composite samples, composed from discrete samples collected at 15-minute intervals during the first three hours of the event or until discharge returned to pre-event levels, also were analyzed for many constituents including major ions, nitrogen, phosphorus, metals, total organic carbon, acid/base-neutral organics, organochlorine pesticides, and polycyclic aromatic hydrocarbons.