From October 1979 through January 1982 the U.S. Geological Survey conducted an urban-runoff study in Bellevue, Washington. The study, done in cooperation with the City of Bellevue, was part of the U.S. Environmental Protection Agency 's National Urban Runoff program. The objectives of the study were to (1) establish a consistent and accessible data base for typical urban watersheds; (2) determine the magnitude and frequency of storm-runoff loads of water-quality constituents from three catchments in the city; (3) develop methods for estimating storm and annual loads of water-quality constituents from unsampled catchments in the study area; and (4) test the effectiveness of storm-water-quality management alternatives, such as street sweeping and detention storage, for the attenuation of constituent loads carried in storm runoff. This report presents data collected during the study period. Data include rainfall and runoff amounts, physical characteristics of the catchments, the chemical quality of storm runoff and in wet- and dry-atmospheric deposition, constituent loads in storm runoff and in wet- and dry-atmospheric deposition, and storm characteristics data, such as rainfall and runoff volumes. (USGS)