Identification of fresh submarine groundwater off the coast of San Diego, USA, using electromagnetic methods

Abstract Climate change has a pronounced effect on water resources in many semiarid climates, causing populated areas such as San Diego County (USA), to become more vulnerable shortages the coming decades. To prepare for decreased supply, is adopting policies decrease use and develop additional local sources of water. One new source freshwater produced by desalination facility that purifies brackish groundwater from coastal Formation. This formation been studied extensively onshore, but little known about geology or quality offshore adjacent continental shelf. Because most systems are interconnected complex, further analysis needed identify geology, possible sequestration shelf, potential pathways saltwater intrusion. comprehensive understanding important because seawater intrusion may limit Formation longevity facilities. Controlled-source electromagnetic methods uniquely suited detecting they sensitive changes pore fluids transition fresh groundwater. paper describes results surface-towed surveys mapped pore-fluid salinity fluid shelf off coast Diego. The indicate considerable volume fresh-to-brackish sequestered both continuous lenses isolated pockets, appear influenced fault shallow stratigraphy.