Remote hydrology: water through the lens of distant machines

Climate change is stressing the American West’s century-old system of water storage and conveyance, 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 USA’s agricultural output on climatologically marginal farmland. Intense management of mountain discharge into the Central Valley, along with oversubscribed rights to surface water, have resulted in unchecked exploitation of the Valley’s groundwater resources and impeded initiatives to use occasional surface water surpluses for aquifer recharge.

New regulation has sparked interest in better information on groundwater availability. Here at Scripps, our lab uses remotely sensed observations of Earth’s gravity and surface motion to infer the dynamics of the hydrological system that feeds the Central Valley aquifer. These techniques track the evolution of mountain water storage at various 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.