EEPS Colloquium: Adrian Borsa

Remote hydrology: water through the lens of distant machines

Climate change is stressing the West's century-old system of water storage and conveyance, both through longer and more intense droughts and periods of exceptional rainfall and flooding.  Nowhere are these challenges more acute than in California’s Central Valley, which produces 25% of the nation’s food on climatologically marginal farmland. Heavy management of often-limited mountain discharge into the Central Valley, along with permanent and oversubscribed rights to surface water, have resulted in unchecked exploitation of the Valley’s long-unregulated groundwater resources and impeded initiatives to use infrequent surface water surpluses for aquifer recharge.

New regulation in the aftermath of California's 2012-2015 drought has sparked interest in better information on groundwater availability.   Here at Scripps, our lab uses remotely sensed geodetic observations of Earth’s gravity and surface motion to infer the dynamics of the coupled surface/groundwater system that feeds the Central Valley aquifer.  These techniques track the evolution of mountain water storage at interannual, seasonal, and individual-storm timescales, and they reveal how this stored water enters and flows through the Central Valley aquifer. Effective management of groundwater resources in the Central Valley will require adoption of data-informed policies, and our hope is that our insights into Central Valley hydrology will prove useful to this end.