Measuring Subsidence in California and Its Impact on Water Conveyance Infrastructure

Agriculture in the Central Valley, California, is made possible by surface water management infrastructure and the groundwater supply. However, groundwater overdraft leads to land subsidence, which in turn threatens flood control and water delivery infrastructure. Monitoring, modeling, and managing land subsidence are crucial to ensure the water supply and its infrastructure remains accessible for the future. Detection of land subsidence is difficult because it is a gradual deformation of the land surface over broad areas that can extend 10s of kilometers. Interferometric synthetic aperture radar (InSAR) is used to detect deformation over time using a series of repeat images that penetrate cloud cover. Satellite and airborne InSAR time series techniques identify and monitor the development of both valley-wide subsidence zones and individual, localized risks to infrastructure.