Study area boundaries of the Tulare Shallow Aquifer Study Unit

The U.S. Geological Survey collected groundwater samples from 95 domestic wells in Tulare and Kings Counties, California in 2014-2015. The wells were sampled for the Tulare Shallow Aquifer Study Unit of the California State Water Resources Control Board Groundwater Ambient Monitoring and Assessment (GAMA) Program Priority Basin Project’s assessment of the quality of groundwater resources used for domestic drinking water supply. Domestic wells commonly are screened at shallower depths than are public-supply wells. The Tulare Shallow Aquifer Study Unit includes the Kaweah, Tule, and Tulare Lake subbasins of the San Joaquin Valley groundwater basin and adjacent areas of the Sierra Nevada. The study unit was divided into equal area grid cells and one domestic well was sampled in each cell. Groundwater samples were analyzed for field water-quality parameters, volatile organic compounds, pesticides and pesticide degradates, nutrients, major ions and trace elements, gross alpha and gross beta particle activities, noble gases, tritium, carbon-14 in dissolved inorganic carbon, stable isotopic ratios of water and dissolved nitrate, and microbial indicators. This dataset identifies the four targeted study areas of the GAMA Tulare Shallow Aquifer Study Unit: (1) the Tule study area, (2) the Kaweah study area, (3) the Tulare Lake study area, and (4) the Kaweah and Tule highlands. The Kaweah and Tule highlands are separate polygons but are considered together as a single study area.