Projection of Climate Change Impacts on Watershed Storage and Hydropower Generation

Abstract:

Under future climate change projections, earlier snowmelt is expected in many regions of the United States. The change in seasonal patterns of streamflow, combined with an increasing frequency of extreme precipitation, could further influence future reservoir management decisions regarding irrigation, water supply, flood protection, and hydropower generation. To evaluate the sensitivity of seasonal reservoir storage and hydropower generation due to future climate change, a storage-based water balance model is developed for over 100 reservoirs that are used for U.S. federal hydropower generation. Historic hydropower generation, hydrologic observations, and unregulated streamflow simulated by a 4-km resolution Variable Infiltration Capacity (VIC) hydrologic model, are used to estimate the likely monthly reservoir release, as well as the maximum and minimum water storage for various watersheds. The storage-based model is then forced with multiple dynamically-downscaled Coupled Model Intercomparison Project Phase 5 (CMIP5) climate projections to simulate the change of watershed storage and hydropower generation under different future scenarios. The proposed methodology could help water managers evaluate the vulnerability of existing energy-water systems and the need to adjust water management objectives in the future.