HydroSource has undertaken several efforts to assess the environmental aspects of hydropower development, provide an inventory of the hydrology, temperature, morphology, and ecological communities within steam segments across the U.S., provide Tools to better predict stream biophysical responses to human disturbances (such as hydropower development), and provide environmental attributes and mitigation databases to inform current and future hydropower projects. These efforts include the Climate Change Impact Assessments, the U.S. Stream Classification Systems, the Eastern Stream Classification Tool, the Environmental Attribution database, and the Environmental Mitigation database and predictive models. 

The Climate Change Impact Assessment effort is a review of the potential effects of climate change on water supplies needed for hydropower generation at federal facilities. Provided on HydroSource are Climate Change Impact Assessment reports, maps, methodology information, and additional publications.

The U.S. Stream Classification System and the Eastern Stream Classification Tool are efforts to group the millions of stream reaches of the Conterminous United States into a layered typology of stream types. The U.S. Stream Classification Web App and Eastern Stream Classification Tool provide platforms for stakeholders to explore, visualize, and query stream classes. 

The Environmental Attribution database includes environmental geospatial data layers to assess environmental topics associated with hydropower. Primary geospatial themes within this framework include: 1) Habitats of Endangered Critical Species Act (ESA) listed species, 2) endangered fish species and fish species of concern, 3) fish traits, 4) protected conservation lands, 5) water quality concerns, 6) water use estimates, 7) recreation and aesthetics, and 8) land disturbance and development. 

The Environmental Mitigation effort provides a database and predictive models that enable interested stakeholders to anticipate mitigation scenarios for specific hydropower projects based on protection, mitigation, and enhancement measures for recent Federal Energy Regulatory Commission (FERC)-licensed projects. The database provides mitigation included in the FERC licenses of non-federal hydropower facilities. The predictive models can be used to anticipate mitigation scenarios based on project location and design characteristics.