The ground beneath California’s San Joaquin Valley is breathing—and not in a good way. According to new research led by Wesley R. Neely at the Scripps Institution of Oceanography at the University of California San Diego, the valley’s surface is sinking at alarming rates, with consequences that ripple far beyond the farm fields. Using high-resolution radar data from the European Space Agency’s Sentinel-1 satellites, Neely and his team mapped ground deformation across the valley during consecutive dry and wet years, revealing how groundwater pumping and surface-water availability are reshaping the landscape—and what that means for energy, agriculture, and water management.
In 2016, a severe drought forced farmers to rely heavily on groundwater, leading to mean subsidence rates of −42.0 millimeters per year, with peaks reaching −345 millimeters at some locations. In contrast, 2017 brought wetter conditions, and although subsidence slowed to −20.4 millimeters per year with peaks of −177 millimeters, the pattern of sinking shifted outward from the valley’s lowest points—hinting at how water moves through the aquifer system. “We’re seeing not just how fast the ground is dropping, but where and when it’s happening,” Neely said. “That tells us a lot about where recharge is entering the system and how groundwater flows beneath the surface.”
The implications are significant for California’s energy sector, especially for oil and gas operations, geothermal energy, and even renewable energy infrastructure like solar farms, all of which depend on stable ground conditions. Subsidence can damage wells, pipelines, and transmission lines, increasing operational risks and maintenance costs. It can also alter groundwater flow paths, potentially affecting aquifer recharge zones critical for long-term water supply.
The study, published in *Water Resources Research* (the English translation of the journal title), demonstrates how satellite-based remote sensing is transforming groundwater management. By tracking seasonal uplift and subsidence, researchers can identify recharge pathways—natural or engineered—that could be enhanced to replenish stressed aquifers. This aligns with California’s Sustainable Groundwater Management Act (SGMA), which requires local agencies to balance groundwater use with available supplies by 2040.
What makes this research stand out is its ability to connect surface deformation to groundwater dynamics in real time. As climate patterns grow more erratic, tools like InSAR (Interferometric Synthetic Aperture Radar) will become indispensable for water managers, policymakers, and industries that depend on stable ground. The next frontier? Integrating these data streams into predictive models that can forecast subsidence risks and guide sustainable groundwater use—before the ground gives out.