Exposure assessments for pesticides used in agriculture require the estimation of both pesticide runoff from fields and resulting concentrations in streams in order to predict the potential aquatic and/or health risk posed by pesticide usage. The STREAM procedures provide a methodology for estimating the mean, maximum, frequency and duration of pesticide concentrations, and the maximum daily and frequency of pesticide runoff for various agricultural crops and regions across the country. STREAM is designed for screening level analyses to provide the order of magnitude accuracy appropriate for exposure assessment with minimal investment in time and resources. Crops included in the current version of STREAM are corn, soybeans, cotton, wheat, and sorghum. (Copyright (c) 1992 John Wiley & Sons, Inc.)