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). For a more detailed description of satellite-based InSAR methods, please see Sneed and others (2013; 2018). For a more detailed description of UAVSAR, please see https://uavsar.jpl.nasa.gov/education/what-is-uavsar.html. The data presented in this data release was provided by Sneed and others (2013; 2018) and will be used to facilitate updates from CVHM to CVHM2 and represent subsidence observations (measurements) using satellite and airborne Interferometric Synthetic Aperture Radar (InSAR) data during 2003–2016. 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. InSAR methods have been used to monitor land subsidence in the Central Valley and are discussed in more detail in the following sections.

Extensive groundwater withdrawal from the unconsolidated deposits in the San Joaquin Valley caused widespread aquifer-system compaction and resultant land subsidence from 1926 to 1970—locally exceeding 8.5 meters. The importation of surface water beginning in the early 1950s through the Delta-Mendota Canal and in the early 1970s through the California Aqueduct resulted in decreased groundwater pumping, recovery of water levels, and a reduced rate of compaction in some areas of the San Joaquin Valley. However, drought conditions during 1976–77, 1987–92, and drought conditions and operational reductions in surface-water deliveries during 2007–10 decreased surface-water availability, causing pumping to increase, water levels to decline, and renewed compaction. The U.S. Geological Survey, in cooperation with the California Department of Water Resources, assessed more recent land subsidence near a 145-kilometer reach of the California Aqueduct in the west-central part of the San Joaquin Valley using Interferometric Synthetic Aperture Radar (InSAR) methods. Analysis presented in Sneed and others (2018) is based, in part, on subsidence contours derived from InSAR data for January 2008–January 2010, and are presented in this data release.

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 observations (measurements) using continuous Global Positioning System (CGPS) methods during 1999–2018. For a more detailed description of CGPS 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 subsidence observations (measurements) using geodetic surveys during 1926–2021 by USGS, Bureau of Reclamation (Reclamation), California Department of Water Resources (DWR), National Geodetic Survey (NGS), and San Luis and Delta-Mendota Water Agency (SLDMWA). 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 measurements. While the model only goes through 2019, the 2021 data is included in this data release for completeness. For a more detailed description of geodetic survey methods, please see Poland and others (1975) and Sneed and others (2020).

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).

An unmanned aerial system was used to acquire hyperspectral image data from the upper Sacramento River in northern California on September 13, 2017, to support research on remote sensing of rivers, particularly retrieval of water depth, and to facilitate efforts to characterize salmon habitat conditions and geomorphic change along the upper Sacramento River. These data were collected by the Nano-Hyperspec imaging system, manufactured by Headwall Photonics, Inc. The flight was conducted by Headwall Photonics, Inc.; Headwall also performed the initial radiometric and geometric data processing. The data were acquired from a DJI Matrice M600 UAS and have a spatial resolution (pixel size) of 0.178 m. The data set consists of 276 spectral bands spanning the visible and near infrared wavelength range from 396.025 - 1005.09 nanometers. Reflectance retrieval was performed by Headwall using their SpectralView software package. The image pixel values represent reflectances and are stored as floating point 32-bit single precision numbers. The image data file has a band sequential (BSQ) interleave and is in an ENVI-compatible file format with an associated header (*.hdr) text file. The image provided in this data release is focuses on the reach of the Sacramento River where it is joined by its tributary Cottonwood Creek. Supporting field data from this reach were collected in coordination with the acquisition of the remotely sensed data.

Multispectral satellite image data from the upper Sacramento River in northern California were acquired on October 18, 2017, to support research on remote sensing of rivers, particularly retrieval of water depth, and to facilitate efforts to characterize salmon habitat conditions and geomorphic change along the upper Sacramento River. These data were collected by the WorldView-3 (WV3) satellite, operated by DigitalGlobe and obtained through the EnhancedView license program administered by the National Geospatial-Intelligence Agency (NGA); the image data remain copyright of DigitalGlobe (2018). DigitalGlobe performed initial radiometric and geometric processing of the image. The data were acquired from the WorldView-3 satellite from an orbit with an altitude of 617 km and have a spatial resolution (pixel size) of 1.36 m. The data set consists of 8 spectral bands spanning the visible and near infrared wavelength range from 400-954 nanometers. The image pixel values represent raw digital counts and conversion to radiance, atmospheric correction, and reflectance retrieval have not been performed for the image included in this data release. The image is in a GeoTIFF format with pixel values stored as 16-bit unsigned integers. The image provided in this data release is a subset focused on the reach of the Sacramento River where it is joined by its tributary Cottonwood Creek. Supporting field data from this reach were collected in coordination with the acquisition of the remotely sensed data.