California Water Science Center


The California Water Science Center has adjusted activities in response to guidance concerning the global COVID-19 pandemic. We will carry on the work of the USGS, while also maintaining the health and safety of our employees and community.  Based on direction from the White House, the CDC, and state and local authorities, we are shifting to a virtual mode. 

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Water Research Projects

Water Research Projects

Over 100 research projects addressing California's key water issues including: long-term water supply and availability, water quality, droughts and floods, climate change, aquatic ecology, the Delta, management of watersheds and groundwater.

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Partnering with Us

Partnering with Us

The USGS partners with local, state, and other federal agencies to provide scientific information needed by water-resources managers across the Nation.

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California Water Data

Basic hydrologic data collection, processing, analysis, dissemination, and archiving are major parts of the California Water Science Center program.

National Water Information System Mapper

Current California Streamflow Conditions

California Runoff

USGS WaterWatch

USGS Flood Event Viewer

California Post-Fire Debris-Flow Maps

California Water-Quality Mapper

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Date published: November 8, 2021

California Waters - Fall 2021 - Vol. I | Issue III

Read the lastest edition of California Waters, the newsletter for the USGS California Water Science Center.

The purpose of USGS California Water Science Center newsletter is to keep its readers updated with current research projects, the latest publications, and other work the center is doing....

Date published: November 4, 2021

USGS Scientists Study Habitat Features in the San Francisco Estuary to Better Inform Conservation Efforts for Aquatic Species

The Pacific coast of the lower 48 US states (Washington, Oregon, and California) has over 400 estuaries of various types. The largest of these is the San Francisco Estuary (San Francisco Bay and Delta) in California.

Date published: September 17, 2021

Public notice for the upgrade and expansion of the water monitoring network in the Sacramento-San Joaquin Delta

The U.S. Geological Survey (USGS) provided the public an opportunity  to review and comment on an Environmental Assessment (EA) for the construction, upgrade, and maintenance of new and existing monitoring stations in the Sacramento-San Joaquin Delta (Delta). Public...


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Year Published: 2022

Populations using public-supply groundwater in the conterminous U.S. 2010; Identifying the wells, hydrogeologic regions, and hydrogeologic mapping units

Most Americans receive their drinking water from publicly supplied sources, a large portion of it from groundwater. Mapping these populations consistently and at a high resolution is important for understanding where the resource is used and needs to be protected. The results show that 269 million people are supplied by public supply, 107 million...

Johnson, Tyler D.; Belitz, Kenneth; Kauffman, Leon J.; Watson, Elise; Wilson, John T.

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Year Published: 2022

Evaluation of ELISA for the analysis of imidacloprid in biological matrices: Cross-reactivities, matrix interferences, and comparison to LC-MS/MS

Imidacloprid is among the most used pesticides worldwide and there are toxicity concerns for nontarget organisms. Accurate and sensitive methods are necessary to quantitate imidacloprid concentrations in biological matrices to better understand their fate and effects. Here we evaluated an enzyme-linked immunosorbent assay (ELISA) kit for...

Gross, Michael S.; Woodward, Emily; Hladik, Michelle

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Year Published: 2021

A basin-scale approach to estimating recharge in the desert: Anza-Cahuilla groundwater basin, CA

The Anza-Cahuilla groundwater basin located mainly in the semi-arid headwaters of the Santa Margarita River watershed in southern California is the principle source of groundwater for a rural disadvantaged community and two Native American Tribes, the Ramona Band of Cahuilla and the Cahuilla. Groundwater in the study area is derived entirely from...

Stern, Michelle A.; Flint, Lorraine E.; Flint, Alan L.; Christensen, Allen H.