H.R. 3857 — Snow Water Supply Forecasting Reauthorization Act of 2025

This section revises the Snow Water Supply Forecasting Program within the Department of the Interior to emphasize integration of snowpack measurement and modeling technologies. Specifically, it (1) eliminates the report on emerging technologies previously required by October 1, 2021, and removes it as a prerequisite for program implementation; (2) requires incorporation of snowpack measurement data with integrated modeling—such as airborne laser altimetry, imaging spectroscopy, and physics-based snowpack and hydrologic modeling—into water supply forecasts and allocations for federal water contractors; (3) mandates coordination with other federal agencies, including the National Oceanic and Atmospheric Administration and Natural Resources Conservation Service; (4) refocuses implementation activities on enhancing snow and water supply forecasting responsive to weather and watershed changes, real-time forecast integration, river basin applications for water management decisions (including interstate), and building partners' capacity; and (5) authorizes $3 million annually for FY2027 through FY2031 (from $15 million aggregate for FY2022 through FY2026). (As background, the program supports Bureau of Reclamation water supply forecasts in the western United States, where snowpack melt provides the majority of surface water for irrigation, municipal, and other uses.)