This data release Child Item contains groundwater elevation data and the associated model/code used to create groundwater elevation surfaces in and around the Elk Hills and North Coles Levee Oil Fields. The data and model provided here are part of an interpretative manuscript by Warden and others (2024). The data compiled and analyzed here are part of the California State Water Resources Control Board Oil and Gas Regional Monitoring Program and the U.S. Geological Survey California Oil, Gas, and Groundwater (COGG) Program.

This data release Child Item contains groundwater elevation data, and the associated model code used to create groundwater elevation surfaces in and around the San Ardo Oil Field, Monterey County, California. The data and model provided here are part of a manuscript by Stanton and others (2025). The modeled water table surface and modeled standard deviation are included in this data release for the spring of 2020. The data compiled and analyzed here are part of the California State Water Resources Control Board Oil and Gas Regional Monitoring Program and the U.S. Geological Survey California Oil, Gas, and Groundwater (COGG) Program.

This data release Child Item contains groundwater elevation data, and the associated model code used to create groundwater elevation surfaces in and around the San Ardo Oil Field, Monterey County, California. The data and model provided here are part of a manuscript by Stanton and others (2025). The modeled water table surface and modeled standard deviation are included in this data release for the spring of 2020. The data compiled and analyzed here are part of the California State Water Resources Control Board Oil and Gas Regional Monitoring Program and the U.S. Geological Survey California Oil, Gas, and Groundwater (COGG) Program.

This data release Child Item contains groundwater elevation data and the associated model/code used to create groundwater elevation surfaces in and around the Lost Hills and Belridge Oil Fields. The data and model provided here are part of an interpretative manuscript by McMahon and others (2023). The data compiled and analyzed here are part of the California State Water Resources Control Board Oil and Gas Regional Monitoring Program and the U.S. Geological Survey California Oil, Gas, and Groundwater (COGG) Program.

This data release Child Item contains groundwater elevation data and the associated model/code used to create groundwater elevation surfaces in and around the Lost Hills and Belridge Oil Fields. The data and model provided here are part of an interpretative manuscript by McMahon and others (2023). The data compiled and analyzed here are part of the California State Water Resources Control Board Oil and Gas Regional Monitoring Program and the U.S. Geological Survey California Oil, Gas, and Groundwater (COGG) Program.

This data release Child Item contains groundwater elevation data and the associated model/code used to create groundwater elevation surfaces in and around the Poso Creek Oil Field. The data and model provided here are part of an interpretative manuscript by McMahon and others (2023). The data compiled and analyzed here are part of the California State Water Resources Control Board Oil and Gas Regional Monitoring Program and the U.S. Geological Survey California Oil, Gas, and Groundwater (COGG) Program.

This data release Child Item contains groundwater elevation data and the associated model/code used to create groundwater elevation surfaces in and around the Poso Creek Oil Field. The data and model provided here are part of an interpretative manuscript by McMahon and others (2023). The data compiled and analyzed here are part of the California State Water Resources Control Board Oil and Gas Regional Monitoring Program and the U.S. Geological Survey California Oil, Gas, and Groundwater (COGG) Program.

This data release contains groundwater elevation data and the associated model/code used to create groundwater elevation surfaces in and around select oil fields in California. The data and model provided here are intended to supplement interpretative manuscripts. Specific study areas will be added as Child Items found in this data release. Groundwater elevations are usually collected from individual wells at discrete times. However, we are often interested in looking at a continuous surface of groundwater levels for a variety of reasons including to examine potential gradients, or directions of groundwater flow. Therefore, we created continuous space-time models of groundwater elevations using a Gaussian process. These datasets have two distinct data types, 1) groundwater elevations measured in water wells obtained from the California Department of Water Resources and the California State Water Resources Control Board's GeoTracker, and 2) elevations of the water table interpreted from oil and gas geophysical well logs. Using both data types provide unique spatial and temporal data coverage in and around oil fields in California. Modeling both data types together allow us to examine lateral gradients between oil fields and adjacent groundwater basins. We can also estimate potential vertical gradients by comparing the modeled water table to fluid levels derived from idle oil and gas wells perforated in deeper hydrocarbon reservoirs. The data compiled and analyzed here are part of the California State Water Resources Control Board Oil and Gas Regional Monitoring Program and the U.S. Geological Survey California Oil, Gas, and Groundwater (COGG) Program. First release: 2023 Revised: May 2024 (ver. 2.0) Revised: September 2025 (ver. 3.0)

This data release contains groundwater elevation data and the associated model/code used to create groundwater elevation surfaces in and around select oil fields in California. The data and model provided here are intended to supplement interpretative manuscripts. Specific study areas will be added as Child Items found in this data release. Groundwater elevations are usually collected from individual wells at discrete times. However, we are often interested in looking at a continuous surface of groundwater levels for a variety of reasons including to examine potential gradients, or directions of groundwater flow. Therefore, we created continuous space-time models of groundwater elevations using a Gaussian process. These datasets have two distinct data types, 1) groundwater elevations measured in water wells obtained from the California Department of Water Resources and the California State Water Resources Control Board's GeoTracker, and 2) elevations of the water table interpreted from oil and gas geophysical well logs. Using both data types provide unique spatial and temporal data coverage in and around oil fields in California. Modeling both data types together allow us to examine lateral gradients between oil fields and adjacent groundwater basins. We can also estimate potential vertical gradients by comparing the modeled water table to fluid levels derived from idle oil and gas wells perforated in deeper hydrocarbon reservoirs. The data compiled and analyzed here are part of the California State Water Resources Control Board Oil and Gas Regional Monitoring Program and the U.S. Geological Survey California Oil, Gas, and Groundwater (COGG) Program.

The U.S. Geological Survey (USGS) in cooperation with the California State Water Resources Control Board compiled and analyzed data for the purpose of mapping groundwater salinity in selected oil and gas fields in California. The data for the Rosedale Ranch oil field include well construction data, digitized borehole geophysical data, geochemical analyses of water samples from oil and gas wells and groundwater wells, geological formation depths, and the groundwater total dissolved solids (TDS) calculations used in the accompanying manuscript. These data have been compiled from many sources and span several decades. The well construction data includes attributes such as the date drilling began (spud date), well depth, the depth of top producing perforation, and borehole orientation. These data have been in archived scanned pages in raster format on the Division of Oil, Gas, and Geothermal Resources (DOGGR) website. Similarly, the borehole geophysical data, measured by oil companies, have been archived in raster format. This project has converted the borehole geophysical data from selected oil and gas wells into a computer readable numerical format. The geochemical analyses have also been archived in scanned formats, but are now compiled and verified for analysis. All of the data collected are part of the California State Water Resources Control Board's Program of Regional Monitoring of Water Quality in Areas of Oil and Gas Production and the USGS California Oil, Gas, and Groundwater (COGG) program.