Andrew L. Soldavini Dara A. Goldrath Jennifer L. Shelton Tyler D. Johnson Elise Watson 20210831 excel formatted tables Reston, VA U.S. Geological Survey https://doi.org/10.5066/P9UYXI95 Andrew L. Soldavini Jennifer S. Harkness Zeno F. Levy Miranda S. Fram 2023 publication n/a US Geological Survey https://doi.org/10.3133/ofr20221122 The U.S. Geological Survey collected groundwater samples from 38 wells used for domestic and small system drinking water supply in the Coachella Valley of California in 2020. The wells were sampled for the Coachella Valley Basin (CODA) Domestic 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 and small system drinking water supplies. Coachella Valley is located in the Desert hydrogeologic province (Johnson and Belitz, 2003) and is structurally divided into four subbasins by the San Andreas fault: the Indio subbasin, the Mission Creek subbasin, the Desert Hot Springs subbasin, and the San Gorgonio Pass subbasin (California Department of Water Resources, 2016). These basins have CA basin designations 7-21.01, 7-21.02, 7-21.03, and 7-21.04 respectively. The study area was divided into 30 equal-area grid cells with at least one well sampled in 26 of the 30 cells. The 10 understanding wells were selected to provide more data in areas where wells were more abundant and to provide more water quality data for wells in the State Small Water System program. In three cases, Sampled wells within 1 mile of an unsampled cell were used to represent unsampled grid cells. Groundwater samples from all 38 wells were analyzed for field water-quality parameters and microbial indicators, volatile organic compounds, pesticides and pesticide degradates, major ions and trace elements, chromium (VI), perchlorate, nutrients, carbon-14 in dissolved inorganic carbon, stable isotopic ratios of water, tritium, per- and polyfluoroalkyl substances (PFAS), sulfur hexafluoride, and noble gases. Groundwater levels were measured in 31 of the 38 wells. All results are presented in this data release, except results sulfur hexafluoride and noble gases. NOTE: The only difference between the original version of this data release and this version is that this data release includes results for tritium. Tritium results were not included in the original version because they were not available at the time of publication. This data release presents the data collected for the Groundwater Ambient Monitoring and Assessment Program Priority Basin Project CODA Domestic Aquifer Study Unit in 2020. These data include: study unit and grid cell boundaries, site information for the 28 grid wells, and 10 understanding wells; water-quality results for samples collected from these 38 sites, and water-quality results for quality-control samples collected from 12 sites. Subsequent publications will present analysis and interpretation of these data. This document provides information necessary to understand the results presented in 10 tables provided in this data release. This data release will support a to be published fact sheet on the quality of water used for domestic drinking water supply in Coachella Valley. Data are also available online at https://waterdata.usgs.gov/nwis and an interactive map can be found at https://ca.water.usgs.gov/projects/gama/water-quality-results/ 20200113 20200701 ground condition Complete As needed World -116.9501 -115.9126 34.0390 33.3890 ISO 19115 Topic Category environment inlandWaters None Groundwater Ambient Monitoring and Assessment Program GAMA USGS Thesaurus domestic well water use drinking water use groundwater water chemistry water quality water sampling groundwater level datasets USGS Metadata Identifier USGS:601d54b7d34e94a4b9fc2b1b Geographic Names Information System Riverside County Coachella Valley California Sonoran Desert Indio Salton Sea None. Please see 'Distribution Info' for details. None. Users are advised to read the data set's metadata thoroughly to understand appropriate use and data limitations. Andrew L Soldavini U.S. Geological Survey, SOUTHWEST REGION Hydrologist mailing address

4165 Spruance Road

San Diego CA 92101-0821 US 619-225-6139 619-225-6101 asoldavini@usgs.gov This study was done in cooperation with the California State Water Resources Control Board. We especially thank the well owners who volunteered or allowed the U.S. Geological Survey to collect a sample from their well and be a part of this study. Microsoft Office 365 (Excel: Version 2002, Word: Version 2002), ArcGIS Pro, Metadata Wizard(Python based GUI) California Department of Water Resources 2016 publication Source of CADWR basin descriptions in abstract. https://water.ca.gov/Programs/Groundwater-Management/Bulletin-118 Descriptions of methods of methods used for assessing attribute accuracy can be found in GAMA_S11_Table_Explanations.docx. Descriptions of methods of methods used for assessing logical consistency of attributes can be found in GAMA_S11_Table_Explanations.docx. Data set is considered complete for the information presented, as described in the abstract. Users are advised to read the rest of the metadata record carefully for additional details. Details on how horizontal positions were established and their accuracy can be found in the spatial metadata file and associated GIS shapefiles. Details on how vertical positions were established and their accuracy can be found in the spatial metadata file and associated GIS shapefiles. Data quality is performed at the individual dataset level for items included in this system; see individual metadata records and GAMA_S11_Table_Explanations.docx for details on how each dataset was quality checked. 2021 Vector G-polygon 2 Albers Conical Equal Area 29.5 45.5 -120.0 23.0 0.0 0.0 coordinate pair 0.6096 0.6096 meters North_American_Datum_1983 GRS_1980 6378137.0 298.257222101 This is the project level metadata file. Metadata files associated with tables presenting groundwater quality results and geospatial datasets for the Mojave Basin Shallow Aquifer Study Unit are provided separately. Not applicable GS ScienceBase U.S. Geological Survey mailing address

Denver Federal Center, Building 810, Mail Stop 302

Denver CO 80225 United States 1-888-275-8747 sciencebase@usgs.gov There is no guarantee concerning the accuracy of the data. No warranty expressed or implied is made regarding the accuracy or utility of the data on any other system or for general or scientific purposes, nor shall the act of distribution constitute any such warranty. Users should be aware that temporal changes may have occurred since this data set was collected and that some parts of this data may no longer represent actual surface conditions. Users should not use this data for critical applications without a full awareness of its limitations. Acknowledgement of the originating agencies would be appreciated in products derived from these data. Any user who modifies the data is obligated to describe the types of modifications they perform. User specifically agrees not to misrepresent the data, nor to imply that changes made were approved or endorsed by the U.S. Geological Survey. Please refer to http://www.usgs.gov/privacy.html for the USGS disclaimer. Digital Data https://doi.org/10.5066/P9UYXI95 None 20230117 Andrew L Soldavini U.S. Geological Survey, SOUTHWEST REGION Hydrologist mailing address

4165 Spruance Road

San Diego CA 92101-0821 US 619-225-6139 619-225-6101 asoldavini@usgs.gov FGDC Biological Data Profile of the Content Standard for Digital Geospatial Metadata FGDC-STD-001.1-1999