Collaboratively Modeling Reservoir Reoperation to Adapt to Earlier Snowmelt Runoff

Across many river basins in the arid Western United States, upstream surface water reservoirs store snowmelt runoff to meet downstream water demand. A collaborative modeling research program in the Truckee River Basin iteratively convenes researchers and local water managers to (1) assess water management challenges under climate change, (2) identify strategies to adapt water management, (3) prioritize research and modeling activities, and (4) collaboratively review findings. This paper presents selected research program results that identify fixed date-based reservoir operations based on stationary climate as a barrier to adapt to warmer temperatures, earlier Sierra Nevada snowmelt runoff, and shifts in streamflow timing. Using an integrated hydrologic and operations model tailored to the river basin, researchers demonstrate that under a warmer climate, earlier peak streamflow compromises reservoir storage. Simulations that allow for earlier storage absorb streamflow timing shifts, providing measurable benefits upstream in the reservoir and downstream for diverse water-use communities. Researchers review simulation results with managers to assess the on-the-ground potential and identify additional research opportunities that meet local information needs. This paper illustrates the utility of integrating local knowledge with applied climate science research to support adaptive water management in snow-fed river basins.