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
California Flood Science
Helping emergency managers and others protect life and property from floods and other water-related hazards
Helping emergency managers and others protect life and property from floods and other water-related hazards
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
Multi-Year USGS and State Collaboration
Multi-Year USGS and State Collaboration
Heterosigma akashiwo in San Fracisco Bay
Heterosigma akashiwo in San Fracisco Bay
California Waters - Fall 2025 - Vol. V | Issue II
California Waters - Fall 2025 - Vol. V | Issue II
Publications
Revisiting chlorophyll a thresholds for San Francisco Bay: Insights from observations of phytoplankton molecular abundance Revisiting chlorophyll a thresholds for San Francisco Bay: Insights from observations of phytoplankton molecular abundance
Harmful Algal Blooms (HABs) are a hazard for coastal environments worldwide; identifying screening thresholds of chlorophyll-a (chl-a) associated with increased risk of HABs is a management priority. Molecular surveillance of coastal phytoplankton and bivalve biotoxins could be used to link chl-a with HAB risk, but requires an understanding of whether the HAB risks increase uniformly as...
Groundwater quality near an oil field in a stream-dominated recharge setting, California, USA Groundwater quality near an oil field in a stream-dominated recharge setting, California, USA
Alluvial valley aquifers are important sources of water supply in many areas but effects of co-located oil and gas development on these resources have not been widely reported, especially in settings where recharge is dominated by stream infiltration. Interpreting the presence of geochemical indicators in the context of hydrology, geology, and other factors provides a more complete...
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