Lake Mendota currently suffers from the effects of polluted runoff from its 232-mi2 watershed (Map 1). Land use in the watershed is 65% agricultural land, 20% existing urban area, 5% wetlands and woodlands, and 10% open water or internally drained land. The watershed includes two counties, three cities (including most of the City of Madison), seven villages, and 12 towns. The watershed was selected in 1993 as a priority watershed project by the Wisconsin Department of Natural Resources’ Nonpoint Source Pollution Abatement Program. The goal of the project is to improve the water quality of the lake by reduc ing nonpoint sources of pollution from the watershed.