California expands groundwater and subsidence monitoring statewide

California’s Department of Water Resources (DWR) has launched a major expansion of its groundwater monitoring program, paired with enhanced subsidence measurement efforts, to better track how aquifer depletion affects land stability. The upgrades are set to provide more frequent and precise insight into ground motion and water level changes across key basins.

As part of the initiative, DWR will outfit additional observation wells with continuous pressure sensors and data loggers, allowing real-time measurement of groundwater levels. These datasets will be integrated with satellite interferometric synthetic aperture radar (InSAR), which detects subtle ground surface deformations over time, to identify zones of compaction and risk.

The expanded scope targets basins under severe stress, including parts of the San Joaquin Valley, where subsidence has damaged infrastructure such as canals, bridges, and levees. The new data will help quantify how much land has compacted historically and where further movement might occur under continued extraction.

DWR is also rolling out technical support and coordination with local water agencies, promoting standard measurement protocols, data sharing, and calibration methods so that comparisons across regions become meaningful. Regional partners will be trained in sensor installation, data validation, and interpretation of deformation signals.

A primary goal is to flag early signs of irreversible compaction, before infrastructure damage accelerates. By correlating groundwater drawdown patterns with observed land subsidence, water managers can better calibrate pumping limits, schedule artificial recharge, or limit further withdrawals in vulnerable areas.