The Central Valley, and particularly the San Joaquin Valley, has a long history of land subsidence caused by groundwater development. The extensive withdrawal of groundwater from the unconsolidated deposits of the San Joaquin Valley lowered groundwater levels and caused widespread land subsidence—reaching 9 meters by 1981. More than half of the thickness of the aquifer system is composed of fine-grained sediments, including clays, silts, and sandy or silty clays that are susceptible to compaction. In an effort to aid water managers in understanding how water moves through the aquifer system, predicting water-supply scenarios, and addressing issues related to water competition, the United States Geological Survey (USGS) developed a new hydrologic modeling tool, the Central Valley Hydrologic Model (CVHM; Faunt and others 2009). The data presented in this data release will be used to facilitate updates to the original CVHM and represent subsidence and aquifer-system compaction observations (measurements) using various methods during 1926–2018. In the context of this report, subsidence is defined as the lowering of the land-surface elevation as a result of aquifer-system compaction and is calculated by differencing repeated elevation measurements derived from geodetic surveys, continuous GPS (CGPS), and Interferometric Synthetic Aperture Radar (InSAR) techniques. Aquifer-system compaction is measured using vertical borehole extensometers to monitor changes in the distance between the top of a cable or pipe that is anchored or placed at depth, and a reference point at or near land surface. For more detailed information on the methods discussed in this data release, please see Sneed and others, 2013; 2018).

The Central Valley, and particularly the San Joaquin Valley, has a long history of land subsidence caused by groundwater development. The extensive withdrawal of groundwater from the unconsolidated deposits of the San Joaquin Valley lowered groundwater levels and caused widespread land subsidence—reaching 9 meters by 1981. More than half of the thickness of the aquifer system is composed of fine-grained sediments, including clays, silts, and sandy or silty clays that are susceptible to compaction. In an effort to aid water managers in understanding how water moves through the aquifer system, predicting water-supply scenarios, and addressing issues related to water competition, the United States Geological Survey (USGS) developed a new hydrologic modeling tool, the Central Valley Hydrologic Model (CVHM; Faunt and others 2009). The data presented in this data release will be used to facilitate updates to the original CVHM, and represent aquifer-system compaction observations (measurements) using borehole extensometer data during 1958–2018 by USGS, California Department of Water Resources, San Luis and Delta-Mendota Water Agency, and Luhdorff and Scalmanini Consulting Engineers. For a more detailed description of borehole extensometer methods, please see Sneed and others (2013; 2018).

The Central Valley, and particularly the San Joaquin Valley, has a long history of land subsidence caused by groundwater development. The extensive withdrawal of groundwater from the unconsolidated deposits of the San Joaquin Valley lowered groundwater levels and caused widespread land subsidence—reaching 9 meters by 1981. More than half of the thickness of the aquifer system is composed of fine-grained sediments, including clays, silts, and sandy or silty clays that are susceptible to compaction. In an effort to aid water managers in understanding how water moves through the aquifer system, predicting water-supply scenarios, and addressing issues related to water competition, the United States Geological Survey (USGS) developed a new hydrologic modeling tool, the Central Valley Hydrologic Model (CVHM; Faunt and others 2009). The data presented in this data release will be used to facilitate updates to the original CVHM, and represent aquifer-system compaction observations (measurements) using borehole extensometer data during 1958–2018 by USGS, California Department of Water Resources, San Luis and Delta-Mendota Water Agency, and Luhdorff and Scalmanini Consulting Engineers. For a more detailed description of borehole extensometer methods, please see Sneed and others (2013; 2018).

The Central Valley, and particularly the San Joaquin Valley, has a long history of land subsidence caused by groundwater development. The extensive withdrawal of groundwater from the unconsolidated deposits of the San Joaquin Valley lowered groundwater levels and caused widespread land subsidence—reaching 9 meters by 1981. More than half of the thickness of the aquifer system is composed of fine-grained sediments, including clays, silts, and sandy or silty clays that are susceptible to compaction. In an effort to aid water managers in understanding how water moves through the aquifer system, predicting water-supply scenarios, and addressing issues related to water competition, the United States Geological Survey (USGS) developed a new hydrologic modeling tool, the Central Valley Hydrologic Model (CVHM; Faunt and others 2009). The data presented in this data release will be used to facilitate updates to the original CVHM, and represent aquifer-system compaction observations (measurements) using borehole extensometer data during 1958–2018 by USGS, California Department of Water Resources, San Luis and Delta-Mendota Water Agency, and Luhdorff and Scalmanini Consulting Engineers. For a more detailed description of borehole extensometer methods, please see Sneed and others (2013; 2018).

The Central Valley, and particularly the San Joaquin Valley, has a long history of land subsidence caused by groundwater development. The extensive withdrawal of groundwater from the unconsolidated deposits of the San Joaquin Valley lowered groundwater levels and caused widespread land subsidence—reaching 9 meters by 1981. More than half of the thickness of the aquifer system is composed of fine-grained sediments, including clays, silts, and sandy or silty clays that are susceptible to compaction. In an effort to aid water managers in understanding how water moves through the aquifer system, predicting water-supply scenarios, and addressing issues related to water competition, the United States Geological Survey (USGS) developed a new hydrologic modeling tool, the Central Valley Hydrologic Model (CVHM; Faunt and others 2009). The data presented in this data release will be used to facilitate updates to the original CVHM, and represent aquifer-system compaction observations (measurements) using borehole extensometer data during 1958–2018 by USGS, California Department of Water Resources, San Luis and Delta-Mendota Water Agency, and Luhdorff and Scalmanini Consulting Engineers. For a more detailed description of borehole extensometer methods, please see Sneed and others (2013; 2018).

This digital dataset contains groundwater level observations for 364 wells, in addition to well construction information, from 1916 to 2014 in the Central Valley, California. Groundwater level observations are used to create groundwater level contours and to calibrate the groundwater levels for the updated Central Valley Hydrologic Model (CVHM2). Groundwater level observations were collected from five sources (USGS, 2018; SLDMWA, 2018; CADWR, 2004; CRNA, 2018).

This digital dataset contains groundwater level observations for 364 wells, in addition to well construction information, from 1916 to 2014 in the Central Valley, California. Groundwater level observations are used to create groundwater level contours and to calibrate the groundwater levels for the updated Central Valley Hydrologic Model (CVHM2). Groundwater level observations were collected from five sources (USGS, 2018; SLDMWA, 2018; CADWR, 2004; CRNA, 2018).

This digital dataset includes three sets of observational data (groundwater level, streamflow, subsidence) used to calibrate the updated Central Valley Hydrologic Model (CVHM2). CVHM2 is a tool that can be used to quantify the sustainability of groundwater resources in the Central Valley.

This digital dataset includes three sets of observational data (groundwater level, streamflow, subsidence) used to calibrate the updated Central Valley Hydrologic Model (CVHM2). CVHM2 is a tool that can be used to quantify the sustainability of groundwater resources in the Central Valley.

This data release provides updated borehole information to build upon and further refine a three-dimensional (3-D) texture model of valley-fill deposits in the Central Valley created by Faunt and others (2009). This model aids in understanding the aquifer system of the entire valley and will be later utilized in a groundwater flow model. The original database contained approximately 8,500 boreholes and with the addition of new data, the model now contains 14,683 boreholes. The new borehole lithologic data was sourced from the California Department of Water Resources (DWR) Online System of Well Completion Reports (OSWCR) and the California Central Valley Groundwater-Surface Water Simulation Model (C2VSim). This dataset contains (1) tabular data of individual borehole general location and construction information, (2) downhole lithologic interval data derived from well driller’s lithology logs and parsed to a series of textural descriptors.