This data release provides a set of Hydrological Simulation Program--Fortran (HSPF) model files representing 5 EPA-selected future climate change scenarios for each of two river basins: Taunton and Sudbury, in Massachusetts. Output from these models are intended for use as input to EPA Watershed Management Optimization Support Tool (WMOST) modeling. Climate scenarios, based on 2036-2065 change from 1975-2004 Representative Concentration Pathways (RCP) 4.5 and 8.5, model effects of air temperature and precipitation changes (in degrees F for air temperature, in percent for precipitation) made to the input historical meteorological time series 1975-2004. Taunton meteorological data is from T.F. Green Airport and the Sudbury meteorological data is from Worcester Regional Airport. Each set of climate scenario model files are derived from the original calibrated model files developed to support WMOST modeling (refer to Source Input fields in this metadata file).