The DWR Periodic Groundwater Levels dataset contains seasonal and long-term groundwater level measurements collected by the Department of Water Resources and cooperating agencies in groundwater basins statewide. It also includes data collected through the Sustainable Groundwater Management Act (SGMA) Portal’s Monitoring Network Module (MNM), and the CASGEM (California Statewide Groundwater Elevation Monitoring) Program. Most measurements are taken manually twice per year to capture the peak high and low values in groundwater elevations. However, the dataset also includes measurements recorded more frequently, monthly, weekly, or daily. This resource also included daily measurements from DWR's automated monitoring network of groundwater sites. For DWRs holdings of groundwater level measurements recorded at more frequent intervals (e.g., hourly), please refer to DWR's “Continuous Groundwater Level Measurements” dataset.

For additional information regarding DWR groundwater levels data collection please visit DWR's Groundwater Management website (https://www.water.ca.gov/Programs/Groundwater-Management). The source data can also be accessed directly from two websites. The Water Data Library (http://wdl.water.ca.gov) provides anonymous access to this and other data sets. The CASGEM online system (https://www.casgem.water.ca.gov/OSS) provides authenticated access to only the the periodic groundwater measurements.

This dataset is maintained primarily in the DWR Enterprise Water Management database and contains information specific to the location of groundwater level monitoring wells and groundwater level measurements collected at these wells. The Stations resource identifies well location coordinates and other supplementary items about the well type. Measurements resources includes information about the time/date a measurement was collected, the entity collecting the measurement, a measurement indicating the depth to groundwater, and quality information about the measurement. The Well Perforations resources contains well construction information identifying the well's screened intervals (not available for all wells).

DWR continuous groundwater level measurements contains continuous time-series data from automated recorders at sites operated by the Department of Water Resources. Readings are taken at 15-minute to one-hour intervals. Some of the readings are relayed to the California Data Exchange Center. However, most of the monitoring sites are visited once every month or two, when readings are off-loaded from data recorders, then finalized and published. Wells monitored for this dataset are located within Butte, Colusa, Glenn, Mendocino, Modoc, Sacramento, San Joaquin, Shasta, Siskiyou, Solano, Sutter, Tehama, Yolo, and Yuba Counties.

Water-level measurements are the principal source of information about changes in groundwater storage and movement in a basin, and how these are affected by various forms of recharge (e.g., precipitation, seepage from streams, irrigation return) and discharge (e.g., seepage to streams, groundwater pumping).

Water-level monitoring involves "continuous" or periodic measurements. Continuous monitoring makes use of automatic water-level sensing and recording instruments that are programmed to make scheduled measurements in wells. This provides a high-resolution record of water-level fluctuations. Resulting hydrographs can accurately identify the effects of various stresses on the aquifer system and provide measurements of maximum and minimum water levels in aquifers. Continuous monitoring may be the best technique to use for monitoring fluctuations in groundwater levels during droughts and other critical periods when hydraulic stresses may change at relatively rapid rates, or when real-time data are needed for making water management decisions see usgs reference.

Groundwater Elevation Change Maps summarize the change in groundwater level measurements over time, collected from wells in the northern Sacramento Valley by the Department of Water Resources (DWR) Northern Region Office (NRO) and monitoring cooperators. Northern Sacramento Valley groundwater levels are measured seasonally, during the annual water year, as part of our ongoing data collection program. Many of the wells have over 30 years of monitoring history, with the longest active monitoring well dating back to 1921. Groundwater level data provides valuable information regarding seasonal fluctuations and long-term changes in groundwater level trends over time. The groundwater level data presented in these figures includes the Sacramento Valley and Redding groundwater basin portions of Shasta, Tehama, Butte, Colusa, Glenn, and Sutter counties and are organized by year, season, well depth, and period of change.

This dataset depicts change in groundwater level at selected monitoring locations (wells) between two specified years, by season. Change values represent change in groundwater level (elevation) by year and season (fall or spring). Other information on the monitoring location is also included. Positive values indicate groundwater has risen (groundwater surface elevation has increased) from the early year to the late year, while negative values indicate groundwater level surface has fallen (decreased in elevation ) from the early year to the late year. Water level monitoring locations and measurements used are selected based on measurement date and well construction information, where available, and approximate groundwater levels in the unconfined to uppermost semi-confined aquifers.

This dataset depicts groundwater level (expressed as depth below ground surface) at selected monitoring locations (wells), by season and year. Other information on the monitoring location is also included. Water level monitoring locations and measurements used are selected based on measurement date and well construction information, where available, and approximate groundwater levels in the unconfined to uppermost semi-confined aquifers.

This dataset depicts groundwater level (expressed as elevation) at selected monitoring locations (wells), by season and year. Other information on the monitoring location is also included. Water level monitoring locations and measurements used are selected based on measurement date and well construction information, where available, and approximate groundwater levels in the unconfined to uppermost semi-confined aquifers.

This dataset depicts contours of estimated change in groundwater piezometric surfaces in the unconfined or uppermost semi-confined aquifers, between two specified years, by season. Contours represent change in groundwater level (elevation) by year and season (fall or spring). The contour interval is 10 ft. The contours represent lines of equal change in groundwater level surface. Positive values indicate groundwater has risen (groundwater surface elevation has increased) from the early year to the late year, while negative values indicate groundwater level surface has fallen (decreased in elevation ) from the early year to the late year. For 'Elevation' type contours, contours represent lines of equal elevation of the estimated groundwater level surface above mean sea level. Higher contour values indicate higher elevations of the estimated groundwater level. Water level measurements used for contouring are selected based on measurement date and well construction information, where available, and approximate groundwater levels in the unconfined to uppermost semi-confined aquifers.

The Groundwater Sustainability Plan (GSP) Monitoring dataset contains the monitoring sites and associated groundwater level, subsidence or streamflow measurements collected by Groundwater Sustainability Agencies (GSA) during implementation of their GSP. All data is submitted to the Department of Water Resources (DWR) through the Sustainable Groundwater Management Act (SGMA) Portal’s Monitoring Network Module (MNM).

The GSP Regulations established the monitoring network criteria (23 CCR § 354.34) and the data and reporting standard for monitoring sites and measurements (23 CCR § 352.4). The data fields associated with these datasets were created by DWR to ensure that GSAs electronically submit monitoring site and measurement data which meets the GSP Regulation’s data and reporting standards. For additional information regarding GSAs, GSPs, and SGMA related monitoring, please view DWR’s SGMA Portal Resources at https://sgma.water.ca.gov/portal/.

The dataset contains the locations for the periodic groundwater elevation monitoring stations that track seasonal and long-term groundwater elevation trends within the California Central Valley. The groundwater level measurements contain time-series data at sites managed by the DWR and local monitoring entities. This dataset is available for download on the SGMA Data Viewer web app, CNRA Open Data Platform, and the CASGEM web application. The data was used for the calibration of the C2VSimFG to perform quality control. Not all of these observed data were used in the calibration of the C2VSimFG due to the insufficient or questionable groundwater observations, such as observed data in subregion 10 and 14, where observed groundwater levels within the area of the Corcoran Clay Layers are highly variable. The groundwater elevation data went through an extensive data review process to determine the CASGEM wells used for the calibration of C2VSimFG. For questions/comments contact gis@water.ca.gov.

Groundwater-quality data collected between 1993 and 2015 were compiled from the U.S. Geological Survey (USGS) National Water Information System (NWIS) database for 722 wells in the San Joaquin Valley (SJV). Groundwater-quality data retrieved included lab analyses of complete major ion data (calcium, magnesium, sodium, potassium, chloride, sulfate, nitrate, alkalinity, bicarbonate, carbonate, silica, and TDS) for 613 samples, and an additional 109 samples with measured values of specific conductance. Most of these wells were sampled as part of the California Groundwater Ambient Monitoring and Assessment (GAMA) Program Priority Basin Project or the USGS National Water Quality Assessment (NAWQA) Program. In addition to GW quality data, the dataset includes well depths, measured or interpolated water levels, summary land-use information, and a tritium-based groundwater age classification. Each well was assigned to a geospatial grid cell in one of six SJV regions (https://www.sciencebase.gov/catalog/item/5892423ee4b072a7ac145e06). These data support the following publication: Hansen, J.A., Jurgens, B.C, Fram, M.S., Quantifying Anthropogenic Contributions to Century-Scale Groundwater Salinity Changes, San Joaquin Valley, California, USA: Science of the Total Environment, vol. XX, no. X, pp. XX-XX, 2018.

Borehole extensometers are a more site specific method of measuring land subsidence. These instruments consist of a pipe or cable anchored at the bottom of a well casing. Pipe or cable extend from the bottom of the well, through geologic layers susceptible to compaction, to the ground surface. The pipe or cable is connected to a recorder that measures the relative distance between the bottom of the bore hole to the ground surface. These instruments are capable of detecting changes in land surface elevation to 1/100th of a foot. When land subsidence and water depth monitoring activities are paired together, hydraulic and mechanical properties of the aquifer system can be determined. DWR monitors 11 extensometers in the Sacramento Valley.

For more information regarding land subsidence monitoring vist: http://www.water.ca.gov/groundwater/landsubsidence/LSmonitoring.cfm

This digital dataset contains the compaction data for 24 extensometers used for observations in the Central Valley Hydrologic Model (CVHM). The Central Valley encompasses an approximate 50,000 square-kilometer region of California. The complex hydrologic system of the Central Valley is simulated using the USGS numerical modeling code MODFLOW-FMP (Schmid and others, 2006). This simulation is referred to here as the CVHM (Faunt, 2009). Utilizing MODFLOW-FMP, the CVHM simulates groundwater and surface-water flow, irrigated agriculture, land subsidence, and other key processes in the Central Valley on a monthly basis from 1961-2003. The total active modeled area is 20,334 square-miles.
Water levels, water-level altitude changes, and water-level and potentiometric-surface altitude maps; streamflows; boundary flows; subsidence; groundwater pumpage; water use; and water-delivery observations were used to constrain parameter estimates throughout the calibration of the CVHM. Measured compaction from extensometers placed in the valley was used as a subsidence calibration target. The extensometer locations were obtained from USGS files and GPS locations. Subsidence monitoring observations can provide valuable information about hydrologic parameters such as elastic and inelastic skeletal specific storage. The CVHM was adjusted to fit the range of measured compaction at the extensometer sites utilizing UCODE-2005 (Poeter and others, 2006) and manual calibration. The calibration target was the measured compaction from several extensometers in the region. Compaction though delayed drainage and re-pressurizing of aquitards was not simulated. The CVHM is the most recent regional-scale model of the Central Valley developed by the U.S. Geological Survey (USGS). The CVHM was developed as part of the USGS Groundwater Resources Program (see "Foreword", Chapter A, page iii, for details).

This dataset has been superseded by https://data.cnra.ca.gov/dataset/tre-altamira-insar-subsidence

This dataset represents measurements of vertical ground surface displacement in Bulletin 118 groundwater basins between spring of 2015 and summer of 2017. Image resolution is 0.0008333 degrees, or approximately 92 meters in north-south direction, and 70-77 meters in east-west direction (low end of range applies to northern latitudes and higher end of range applies to lower latitudes). Vertical ground surface displacement rates are derived from Interferometric Synthetic Aperture Radar (InSAR) data that are collected by the European Space Agency (ESA) Sentinel-1A satellite and processed by the National Aeronautics and Space Administration (NASA) Jet Propulsion Laboratory (JPL), under contract with to the California Department of Water Resources (DWR). JPL presented preliminary processing results in the Progress Report: Subsidence in California, March 2015 – September 2016, and submitted a later version of the processing results that are still preliminary to the California Department of Water Resources (DWR). These files provided by JPL to DWR are multiband floating point GeoTIFFs with each band representing a date. GeoTIFF pixel values are in inches equal to the cumulative vertical displacement from the first date. JPL processed Sentinel-1A InSAR data separately for three different geographic regions; The Sacramento Valley, the San Joaquin Valley, and the South Central Coast. DWR temporarily interpolated the JPL data to end-of-month values, merged the resulting rasters from all three regions into a single raster for each month, and clipped all rasters to Bulletin 118 groundwater basins. DWR derived rasters for total vertical displacement relative to May 31, 2015, as well as rasters for annual vertical displacement rates, both in monthly time steps. Data are considered public domain. DWR makes no warranties or guarantees — either expressed or implied — as to the completeness, accuracy, or correctness of the data. DWR neither accepts nor assumes liability arising from or for any incorrect, incomplete, or misleading subject data. This is an official DWR Image Service, published on 2/9/2018 by Ben Brezing of the DWR Division of Statewide Integrated Water Management, who may be contacted at Benjamin.brezing@water.ca.gov or (916) 651-9291. Date of acquisition: Between Spring of 2015 and Spring of 2017. Date of production: 2017. Date of delivery of product: Delivered from NASA JPL to DWR in September of 2017. Processing steps: See Progress Report: Subsidence in California, March 2015 – September 2016, Tom G. Farr, Cathleen E. Jones, Zhen Liu, Jet Propulsion Laboratory, 2016. Pixel value definitions: Vertical ground surface displacement in inches for time period specified above. Positional accuracy: See Progress Report: Subsidence in California, March 2015 – September 2016, Tom G. Farr, Cathleen E. Jones, Zhen Liu, Jet Propulsion Laboratory, 2016.

This digital geospatial data set contains the locations, values, and uncertainties of 700 hydraulic-head observations used in the steady-state, prepumped period of the transient model of the Death Valley regional ground-water flow system (DVRFS), a 100,000-square-kilometer region of southern Nevada and California. Hydraulic-head observations, which are the composite of one or more water-level measurements made at a well, are used to calibrate ground-water flow models. To develop hydraulic- head observations for the DVRFS ground-water flow model, nearly all available water levels for the DVRFS region through 2004 were compiled in Ground-Water Site Inventory (GWSI), the ground-water component of the U.S. Geological Survey (USGS) National Water Information System (NWIS) database. Water levels suitable for developing hydraulic-head observations representative of regional, steady-state ground-water flow conditions were identified through analyses. The resulting water levels were averaged for each well to produce one hydraulic-head observation value at each of 700 wells. The uncertainty of each hydraulic-head observation was statistically quantified from the values of uncertainties associated with well altitude and location, nonsimulated transient stress, and measurement accuracy.

This digital dataset defines the well locations, perforated intervals, and time series of hydraulic-head observations used in the calibration of the transient hydrologic model of the Central Valley flow system. The Central Valley encompasses an approximate 50,000 square-kilometer region of California. The complex hydrologic system of the Central Valley is simulated using the U.S. Geological Survey (USGS) numerical modeling code MODFLOW-FMP (Schmid and others, 2006b). This simulation is referred to here as the Central Valley Hydrologic Model (CVHM) (Faunt, 2009). Utilizing MODFLOW-FMP, the CVHM simulates groundwater and surface-water flow, irrigated agriculture, land subsidence, and other key processes in the Central Valley on a monthly basis from 1961-2003. The USGS and CA-DWR maintain databases of key wells in the Central Valley that are web-accessible (http://waterdata.usgs.gov and http://www.water.ca.gov/waterdatalibrary/, respectively). These data were combined to form a database of available water levels throughout the Central Valley from 1961 to 2003. More than 850,000 water-level altitude measurements from more than 21,400 wells have been compiled by the USGS or CA-DWR and have been entered into their respective databases. However, only a small portion of these wells have both sufficient construction information to determine the well-perforation interval and water-level measurements for the simulation period. For model calibration, water-level altitude data were needed that were (1) distributed spatially (both geographically and vertically) throughout the Central Valley; (2) distributed temporally throughout the simulation period (years 1961-2003); and (3) available during both wet and dry climatic regimes. From the available wells records, a subset of comparison wells was selected on the basis of perforation depths, completeness of record, climatic intervals, and locations throughout the Central Valley. Water-level altitude observations (19,725) for 206 wells were used as calibration targets during parameter estimation. The CVHM is the most recent regional-scale model of the Central Valley developed by the U.S. Geological Survey (USGS). The CVHM was developed as part of the USGS Groundwater Resources Program (see "Foreword", Chapter A, page iii, for details).

This digital dataset defines the well locations for hydraulic-head observations used in the calibration of the transient hydrologic model of the Central Valley flow system. The Central Valley encompasses an approximate 50,000 square-kilometer region of California. The complex hydrologic system of the Central Valley is simulated using the USGSs numerical modeling code MODFLOW-FMP (Schmid and others, 2006). This application is referred to here as the Central Valley Hydrologic Model (CVHM) (Faunt, 2009). Utilizing MODFLOW-FMP, the CVHM simulates groundwater and surface-water flow, irrigated agriculture, land subsidence, and other key processes in the Central Valley on a monthly basis from 1961-2003. The USGS and DWR maintain databases of key wells in the Central Valley that are web-accessible (http://waterdata.usgs.gov and http://www.water.ca.gov/waterdatalibrary/, respectively). These data were combined to form a database of available water levels throughout the Central Valley from 1961 to 2003. More than 850,000 water-level altitude measurements from more than 21,400 wells have been compiled by the USGS or DWR and have been entered into their respective databases. However, only a small proportion of these wells have both sufficient construction information to determine the well-perforation interval and water-level measurements for the simulation period. For model calibration, water-level altitude data were needed that were (1) distributed spatially (both geographically and vertically) throughout the Central Valley, from the valley trough to the foothills; (2) distributed temporally throughout the simulation period (1961-2003); and (3) available during both wet and dry climatic regimes. From the available wells records, a subset of comparison wells was selected on the basis of perforation depths, completeness of record, climatic intervals, and locations throughout the Central Valley. Water-level altitude observations (19,725) for 206 comparison wells were used as calibration targets during parameter estimation. The CVHM is the most recent regional-scale model of the Central Valley developed by the U.S. Geological Survey (USGS).The CVHM was developed as part of the USGS Groundwater Resources Program (see "Foreword", Chapter A, page iii, for details).