Climate Change Adaptations for California’s San Francisco Bay Area Water Supplies

Abstract

The impact of climate changes on both sea level and the temporal and spatial distribution of runoff will affect water supply reliability and operations in California. To meet future urban water demands in the San Francisco Bay Area, local water managers can adapt by changing water supply portfolios and operations. An engineering economic model, CALVIN, which optimizes water supply operations and allocations, was used to explore the effects on water supply of a severely warmer drier climate and substantial sea level rise, and to identify economically promising long-term adaptations for San Francisco Bay Area water systems. This modeling suggests that Bay Area urban water demands can be largely met, even under severe forms of climate change, but at a cost. Costs are from purchasing water from agricultural users (with agricultural opportunity costs), expensive water recycling and desalination alternatives, and some increases in water scarcity (costs of water conservation). The modeling also demonstrates the importance of water transfer and intertie infrastructure to facilitate flexible water management among Bay Area water agencies. The intertie capacity developed by Bay Area agencies for emergencies, such as earthquakes, becomes even more valuable for responding to severe changes in climate.