Data

Providing current data for analysis, forecasting, and research

Basic hydrologic data collection, processing, analysis, dissemination, and archiving are major parts of the California Water Science Center program. Streamflow data, for example, are used for flood and water-supply forecasts, planning and design, river regulation, streamflow statistics, and research investigations. Much of the data are available on a near-real-time basis by satellite telemetry.

California Water Dashboard

View California's real-time stream, lake, reservoir, precipitation, water quality, and groundwater stations in context with current weather and hazard conditions.

Current Conditions

California Groundwater Quality

This interactive webmap plots water-quality data from domestic and public-supply wells sampled by the USGS for the California GAMA Priority Basin Project, and allows users to download datasets.

Water Quality Data

California Water Data

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November 13, 2023

Abundance and Distribution of Fishes in Clear Lake, Lake County, California (ver. 3.0, December 2025) Abundance and Distribution of Fishes in Clear Lake, Lake County, California (ver. 3.0, December 2025)

Field data for fishes sampled using bottom and surface gill nets during daylight hours in Clear Lake, California, USA. This data release includes all measured environmental parameters and fish taxa included in the analysis. First posted - November 8, 2023 Revised - December 18, 2024 (version 2.0) Revised - December 4, 2025 (version 3.0)

California Water Science Center

November 6, 2023

Water Quality Data from Ponds on Bouldin Island in the Sacramento-San Joaquin Delta, California (ver. 2.0, February 2025) Water Quality Data from Ponds on Bouldin Island in the Sacramento-San Joaquin Delta, California (ver. 2.0, February 2025)

This data release includes water quality and zooplankton data collected from ponds on Boudin Island in the Sacramento-San Joaquin Delta. Data were collected in the Bouldin East and Bouldin West ponds concurrently with a Delta Smelt Deployment Experiment which involved three cages in each pond with approximately 60 Delta Smelt (Hypomesus transpacificus) in each cage. There were two fish...

California Water Science Center

November 6, 2023

2021 Organic Matter Research Lab Vectorized Fluorescence Data 2021 Organic Matter Research Lab Vectorized Fluorescence Data

The USGS CAWSC Organic Matter Research Laboratory (OMRL) provides laboratory services and support to regional and national projects in the analysis of organic matter using the latest methods in absorbance and fluorescence spectroscopy. Optical measurements such as absorbance and fluorescence are used to gain insight into dissolved organic matter (DOM) composition, and can also serve as...

California Water Science Center

November 1, 2023

Irrigation water use reanalysis for the 2000-20 period by HUC12, month, and year for the conterminous United States (ver. 2.0, September 2024) Irrigation water use reanalysis for the 2000-20 period by HUC12, month, and year for the conterminous United States (ver. 2.0, September 2024)

This data release provides a monthly irrigation water use reanalysis for the period 2000-20 for all USGS Watershed Boundary Dataset of Subwatersheds (HUC12) in the conterminous United States (CONUS). Results include reference evapotranspiration (ETo), actual evapotranspiration (ETa), irrigated areas, consumptive use, and effective precipitation for each HUC12. ETo and ETa were estimated...

California Water Science Center, Integrated Water Availability Assessments

October 24, 2023

2021 Organic Matter Research Lab Full Spectra Absorbance Data 2021 Organic Matter Research Lab Full Spectra Absorbance Data

California Water Science Center

October 23, 2023

CalPUR-LUE CalPUR-LUE

Estimating High Resolution Multi-Cropped Irrigated Land Use Using a Pesticide Use Reporting Database in California Estimating the amount of water needed for agriculture is vital for food and water security. These estimates rely on maps of crop type and acreage that have limited ground-truthing or represent multiple years or regional cropping patterns. In regions where crops change...

California Water Science Center

October 18, 2023

Current-use pesticides in tree swallow (Tachycineta bicolor) prey Current-use pesticides in tree swallow (Tachycineta bicolor) prey

Analysis of biological tissues or direct sources of food may better characterize exposure of non-target organisms to current-use pesticides. Food boluses were collected from tree swallow (Tachycineta bicolor) nestlings using a non-lethal, ligature method and were composited based on nest. The ligatures, which prevented the bolus from being swallowed, were placed on nestlings for 1 h...

California Water Science Center

October 12, 2023

Pharmaceutical Data from the California Groundwater Ambient Monitoring and Assessment Priority Basin Project (GAMA-PBP) Domestic Well Groundwater Quality Studies, 2014 - 2021 Pharmaceutical Data from the California Groundwater Ambient Monitoring and Assessment Priority Basin Project (GAMA-PBP) Domestic Well Groundwater Quality Studies, 2014 - 2021

The U.S. Geological Survey collected groundwater samples from 537 domestic wells for pharmaceutical compounds between 2014 and 2021 from 9 different study units. These wells were sampled as part 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...

California Water Science Center

September 29, 2023

Relative distance of California's Central Valley from trough to valley edge and supporting data Relative distance of California's Central Valley from trough to valley edge and supporting data

California's Central Valley ranges from the mountain fronts toward a central trough, mainly defined by the San Joaquin and Sacramento Rivers, and the relative distance from trough to valley edges is of interest. This data release provides supplemental data for the USGS Professional Paper 1766, titled Groundwater Availability of the Central Valley Aquifer, California and provides...

California Water Science Center

September 28, 2023

Data for Machine Learning Predictions of Nitrate in Shallow Groundwater in the Conterminous United States Data for Machine Learning Predictions of Nitrate in Shallow Groundwater in the Conterminous United States

An extreme gradient boosting (XGB) machine learning model was developed to predict the distribution of nitrate in shallow groundwater across the conterminous United States (CONUS). Nitrate was predicted at a 1-square-kilometer (km) resolution at a depth below the water table of 10 m. The model builds off a previous XGB machine learning model developed to predict nitrate at domestic and...

California Water Science Center

September 25, 2023

Inverse Model Data for: Salinity trends in a groundwater system supplemented by 50 years of imported Colorado River water Inverse Model Data for: Salinity trends in a groundwater system supplemented by 50 years of imported Colorado River water

Data provided here describe the contribution of up to 7 different water sources to the major ion geochemistry of U.S. Geological Survey (USGS) and California State Water Resources Control Board Division of Drinking Water (CA-DDW) groundwater samples within the Indio Subbasin of the Coachella Valley, California. The Inverse Geochemical Modeling was performed in the USGS's PHREEQC ver. 3...

California Water Science Center

September 14, 2023

Assessing spatial variability of nutrients, phytoplankton and related water-quality constituents in the California Sacramento-San Joaquin Delta at the landscape scale: 2020-2021 High-resolution mapping surveys Assessing spatial variability of nutrients, phytoplankton and related water-quality constituents in the California Sacramento-San Joaquin Delta at the landscape scale: 2020-2021 High-resolution mapping surveys

The dataset documents the spatial and temporal variability of nutrients, phytoplankton, and related water quality parameters at high spatial resolution in the Sacramento-San Joaquin River Delta and Suisun Bay of California, USA. The dataset includes nitrate, ammonium, orthophosphate, dissolved organic carbon, temperature, conductivity, dissolved oxygen, and chlorophyll as well as...

California Water Science Center