The USGS has conducted subsidence studies in California since the 1950s. Today, subsidence studies carried out by the USGS California Water Science Center integrate a suite of space-based (for example, InSAR, GPS) and ground-based (for example, extensometers) high-frequency measurements by using statistical and simulation modeling techniques. This produces high-quality scientific information about subsidence status and trends. Results of USGS Land Subsidence Studies help California water managers assess and track the state of water resources in their area and across the State. It also helps them assess the effectiveness of management strategies aimed at achieving sustainable groundwater and surface-water management goals.