This headwaters to groundwater investigation will examine hydrologic sensitivities of California headwaters and agricultural demand to changing climate, and will consider plausible societal adaptations. By exploiting information in the historical record and its interaction with physical characteristics of the basins and characteristics and behavior of the strategies for water management as precipitation varies, temperatures warm, and population grows. It integrates study of the climate, hydrology, ecosystems, energy, and society influencing future water management, focused on aquifer storage and recovery in an adaptive framework. Uncertainties and responses to resolve include:
- Trends and variability in a future that likely experiences a greater fraction of precipitation as rain instead of snow, earlier snowmelt, and higher rates of evapotranspiration.
- Responses of ecosystems to changing quantity and timing of water supply, and feedback on precipitation, evapotranspiration, and the overall water balance.
- Response of headwater catchments and uncertainty in future river discharge characteristics.
- Storage and use of water in the subsurface, considering efficiency of storage and recharge, and energy requirements for recovery.
- Responses of water and agricultural management agencies and other institutions to changing supply and demand, including management of water markets to both agricultural and urban users.
- Lastly, resolution of the effect of uncertainties themselves on abilities to manage water for multiple objectives and adaptation to changes in supply and demand.