Water-quality and streamflow data are available at https://doi.org/10.5066/F7P55KJN. Calculated nutrient and sediment loads are available at https://doi.org/10.5066/P96H2BDO. Inputs to the Chesapeake Bay Program's watershed model are available at https://doi.org/10.5066/P93SVYQG. Estimated nutrient and sediment management-practice load reductions are available at https://doi.org/10.5066/P95WG7G0. Expected physical effects of agricultural conservation practices are available at https://doi.org/10.5066/P9VY95KT. This dataset is associated with the following publication: Webber, J., j. Chanat, J. Clune, O. Devereux, N. Hall, R. Sabo, and Q. Zhang. Evaluating water-quality trends in agricultural watersheds prioritized for management-practice implementation. JOURNAL OF ENVIRONMENTAL MANAGEMENT. Elsevier Science Ltd, New York, NY, USA, 305-330, (2024).