Water Quality
Providing foundational data and scientific analysis to address water quality issues facing California
Providing foundational data and scientific analysis to address water quality issues facing California
Surface Water
Understanding the science about California surface-water use for irrigation, public consumption, and ecosystems
Understanding the science about California surface-water use for irrigation, public consumption, and ecosystems
Science Programs and Partnerships
Supplying necessary scientific information to local, state, and federal agencies, and non-governmental organizations
Supplying necessary scientific information to local, state, and federal agencies, and non-governmental organizations
Aquatic Ecology
Gaining better understanding of the effects that human activity, hydrologic extremes, and climate change have on aquatic ecosystems
Gaining better understanding of the effects that human activity, hydrologic extremes, and climate change have on aquatic ecosystems
Groundwater
Using science to assess and quantify the availability and quality of California's groundwater resources
Using science to assess and quantify the availability and quality of California's groundwater resources
California Drought
Monitoring the effects of drought in California through data collection and research
Monitoring the effects of drought in California through data collection and research
California Water Science Center
The U.S. Geological Survey, California Water Science Center provides reliable, impartial, foundational data and scientific analysis to address water issues facing California today. We conduct hydrologic monitoring and investigative studies in partnership with Tribal, federal, state, and local agencies to assist them in making decisions.
Historical Floods
Historical Floods
Storms unleash torrential rain and intense winds, posing significant challenges to infrastructure and triggering widespread flooding. Since it became a state in 1850, California has experienced numerous large storms and floods.
Golden State Reflections
Golden State Reflections
Our science supports the Department’s commitment to national resilience and resource management by providing expertise and delivering well-documented data and interpretive products.
California Water & Drought Data
California Water & Drought Data
Basic hydrologic data collection, processing, analysis, dissemination, and archiving are major parts of the California Water Science Center program.
News
As Wildfires Burn, Rainfall Can Strip Oxygen From Rivers, Killing Fish
As Wildfires Burn, Rainfall Can Strip Oxygen From Rivers, Killing Fish
California Water Science Center Scientists Share their Research at 2026 IEP Annual Workshop
California Water Science Center Scientists Share their Research at 2026 IEP Annual Workshop
California Waters – Spring 2026 - Vol. VI | Issue I
California Waters – Spring 2026 - Vol. VI | Issue I
Publications
Co-occurrence of pesticides and pharmaceuticals and personal care products (PPCPs) across Zostera marina (common eelgrass) communities Co-occurrence of pesticides and pharmaceuticals and personal care products (PPCPs) across Zostera marina (common eelgrass) communities
Anthropogenic pressures are driving changes in eelgrass communities, which are altering baseline conditions in estuarine environments. Field detections have validated the transport of land-sourced pollutants to aquatic systems; however, studies rarely sample concurrently for pesticides, and pharmaceuticals and personal care products (PPCPs) across environmental compartments. Moreover...
Effects of fipronil bait pellets on two cricetid species: Potential implications for plague mitigation and wildlife conservation Effects of fipronil bait pellets on two cricetid species: Potential implications for plague mitigation and wildlife conservation
We evaluated the effects of fipronil bait pellets on two cricetids that commonly occupy colonies of black-tailed prairie dogs (Cynomys ludovicianus; BTPDs): western deer mice (Peromyscus sonoriensis) and northern grasshopper mice (Onychomys leucogaster). In one experiment, bait pellets (0.96 mg fipronil/bait) were applied at 75 baits/ha to three 1.44-ha plots on a BTPD colony. Mouse...
Status and understanding of groundwater quality in the San Joaquin Valley Kern County subbasin domestic-supply aquifer study unit, 2022—California GAMA Priority Basin Project Status and understanding of groundwater quality in the San Joaquin Valley Kern County subbasin domestic-supply aquifer study unit, 2022—California GAMA Priority Basin Project
The quality of water accessed by domestic wells (here referred to as domestic groundwater resources) in the San Joaquin Valley Kern County subbasin (basin number 5-022.14) was assessed as part of the California Groundwater Ambient Monitoring and Assessment (GAMA) Program Priority Basin Project (GAMA-PBP), in cooperation with the California State Water Resources Control Board. Kern County...
Science
Evaluation of Groundwater Resources in the Adelaida Area of San Luis Obispo County, California
Stakeholders in San Luis Obispo County are concerned that the increased demand for water use has, and will continue to, affect groundwater levels and availability in the Adelaida area. To address stakeholder concerns, the County of San Luis Obispo Board of Supervisors has asked the USGS to conduct a comprehensive evaluation of groundwater resources of the Adelaida area.
WaterMAP: Water Monitoring Above the Planet
WaterMAP, or Water Monitoring Above the Planet, is an interactive web application that brings together surface water observations across the U.S. The application allows users to explore water conditions over time using both remotely sensed satellite and field measured data.
Where Land Meets Sea: USGS Science for Resilient Coastal Habitats
USGS coastal science plays a critical role in supporting the effective, science-based management of coastal ecosystems, where the biodiversity of land and sea meet. It provides managers with the information they need to make sound decisions. Through cutting-edge research, predictive modeling, and decision-support tools, USGS empowers resource managers to make informed, science-based choices. From...
By
Ecosystems Mission Area, Land Management Research Program, California Water Science Center, Eastern Ecological Science Center, Forest and Rangeland Ecosystem Science Center, Lower Mississippi-Gulf Water Science Center, Pacific Coastal and Marine Science Center, Western Ecological Research Center (WERC), Western Fisheries Research Center, Western Geographic Science Center, Wetland and Aquatic Research Center