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
California Waters – Spring 2026 - Vol. VI | Issue I
California Waters – Spring 2026 - Vol. VI | Issue I
Predicting Harmful Algal Blooms and Toxicity in the San Francisco Estuary
Predicting Harmful Algal Blooms and Toxicity in the San Francisco Estuary
San Luis Obispo Field Office Grand Opening
San Luis Obispo Field Office Grand Opening
Publications
The global proliferation of aquatic, benthic Microcoleus: Taxonomy, distribution, toxin production, ecology, and future directions The global proliferation of aquatic, benthic Microcoleus: Taxonomy, distribution, toxin production, ecology, and future directions
There have been sporadic reports of aquatic, benthic Microcoleus proliferations in freshwater rivers, lakes, and reservoirs for four decades, with reports increasing in frequency over the last twenty years, suggesting a possible rise in their global distribution, frequency, and intensity. Microcoleus can produce anatoxins which are neurotoxic, and ingestion of toxic mats has caused...
Opportunities and challenges in using Solid Phase Adsorption Toxin Tracking (SPATT) samplers for monitoring cyanotoxins in freshwater and estuarine environments Opportunities and challenges in using Solid Phase Adsorption Toxin Tracking (SPATT) samplers for monitoring cyanotoxins in freshwater and estuarine environments
Cyanobacterial toxins (cyanotoxins) represent a substantial threat to drinking water supplies and safe recreational uses of freshwater resources in watersheds worldwide. Monitoring cyanotoxins can be difficult because toxin events are variable in both space and time, are not always persistent, can be moved easily by wind and currents, and may be degraded biotically or abiotically. Thus...
Deep groundwater total dissolved solids mapping in the Dakota Group, Williston Basin, USA Deep groundwater total dissolved solids mapping in the Dakota Group, Williston Basin, USA
Growing concern about the quantity of available freshwater around the world has led to interest in surveying groundwater total dissolved solids (TDS) below water well depths. Deep TDS has not been systematically mapped, and there is much to learn about the distribution and controls on deeper groundwater. In sedimentary basins across the United States, groundwater resources often overlie
Science
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...
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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
Bioenergy and Pesticides: Lessons from the AltEn Bioenergy Plant
Ethanol production from seed corn, while reducing waste and promoting renewable energy, can have environmental and health implications. A USGS study on a former bioenergy plant that received pesticide-coated seeds used for ethanol production, revealed that the process led to contaminated wastewater and solid residue, resulting in elevated pesticide levels in nearby surface waters even after the...
Healthy Fish and Wildlife: Community Livelihoods, Fishing and Hunting Heritage, Recreation, and Economic Security
Healthy fish and wildlife underpin the economic vitality, food security, recreational enjoyment, and cultural heritage of fishing and hunting in communities across the United States. Fishing and hunting resources scale from the personal recreation of families to multi-billion-dollar industries. Recognizing these critical connections, the U.S. Geological Survey (USGS) works to understand, protect...
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Ecosystems Mission Area, Contaminant Biology, Environmental Health Program, Toxic Substances Hydrology, California Water Science Center, Central Midwest Water Science Center, Columbia Environmental Research Center, Eastern Ecological Science Center, Forest and Rangeland Ecosystem Science Center, Upper Midwest Environmental Sciences Center, Upper Midwest Water Science Center