California Water Supply and Reservoir Storage for Warmer vs. Warmer-Drier Climate Conditions

摘要

Economic effects and adaption of California's water supply to three climate change scenarios are explored using CALVIN, a hydro-economic optimization model. CALVIN is a statewide model of California's water supply that includes most agricultural and urban demands and major infrastructure in the Central Valley and southern California. Two simulated climate scenarios were used to analyze the independent and combined effects of temperature and precipitation on water supply: 1) a warmer climate with historically observed annual runoff totals; and 2) a warmer and drier climate where runoff is reduced based on a downscaled climate model simulation for California (GFDL A2). These two climate scenarios are compared to historical hydrologic conditions. Water deliveries and scarcity under economically optimal conditions are obtained along with surface reservoir storage and operations. Results include comparison of water scarcity and costs between scenarios, changes in water supply availability, and reservoir operation adaptations and storage for each climate condition. This study suggests that water scarcity tends to be more sensitive to decreased precipitation and warming compared to higher temperatures alone. Coordinated resource management serves well to reduce water scarcity under all scenarios.