This data release provides a set of Hydrological Simulation Program--Fortran (HSPF) model files representing five EPA-selected future climate change scenarios for the Farmington River Basin in Massachusetts and Connecticut. 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 changes from 1975-2004 for Representative Concentration Pathways (RCP) 4.5 and 8.5, model the 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 for 1975-2004. Meteorological data are from the following climate stations in Connecticut: Hartford Airport, Burlington, and Norfolk. Each set of climate scenario model files are derived from the original calibrated model files created by EPA and the Connecticut Department of Energy and Environmental Protection Bureau of Water Management to evaluate nutrient sources and loadings to Long Island Sound and assessment of impacts of Best-Management Practices (BMP), and later extended by U.S. Geological Survey (USGS) to support WMOST modeling (refer to Source Input fields in this metadata file).