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
Nevada and California Water Science Centers Join Forces at 2026 Tahoe Summit
Nevada and California Water Science Centers Join Forces at 2026 Tahoe Summit
From Streamgage to Smartphone
From Streamgage to Smartphone
A More Intelligent World
A More Intelligent World
Publications
High-resolution landscape-scale maps of nutrients, phytoplankton, and related water-quality constituents in Suisun Bay and the Sacramento–San Joaquin Delta, California, during 2018—Results from high-resolution underway surveys High-resolution landscape-scale maps of nutrients, phytoplankton, and related water-quality constituents in Suisun Bay and the Sacramento–San Joaquin Delta, California, during 2018—Results from high-resolution underway surveys
We examined the abundance and distribution of nutrients and phytoplankton in the tidal aquatic environments of the Sacramento–San Joaquin Delta (Delta) and Suisun, Grizzly, and Honker Bays in California by completing three spatial surveys that used continuous underway high frequency (1 hertz) measurements and sampling onboard a high-speed boat. Surveys were conducted in May, July, and...
Cyanobacteria Assessment Network: Pilot study with Sentinel-2 derived chlorophyll data Cyanobacteria Assessment Network: Pilot study with Sentinel-2 derived chlorophyll data
Harmful algal blooms (HABs) affect global water quality, limiting uses like recreation and consumption because of excessive algal biomass and toxin production. These blooms cause surface scums, taste and odor issues, hypoxia, and negative health and socioeconomic impacts. The US Army Corps of Engineers (USACE) manages over 400 lakes and reservoirs and seeks to improve monitoring of HABs...
Evaluation and synthesis of the Yolo Bypass fish monitoring program Evaluation and synthesis of the Yolo Bypass fish monitoring program
The Yolo Bypass is the largest functional remnant floodplain of the Sacramento River, providing benefits to aquatic taxa of the San Francisco Bay and Sacramento–San Joaquin Delta (hereafter, Bay-Delta). Because of the Yolo Bypass’s vital role in flood control and its ecological effects, the California Department of Water Resources started the Yolo Bypass Fish Monitoring Program (YBFMP)...
Science
Stormwater Recharge in Los Angeles
The Greater Los Angeles region faces growing pressure to secure reliable, sustainable water supplies. Local leaders have set a goal of meeting 80 percent of its water needs from local sources by 2045, up from roughly 10 percent in recent years. Capturing water and storing it underground for later use is one of the ways the region plans to reach that goal. This practice of storing more water in...
Santa Ana River Native Fish Study
Native Fish Population and Habitat Study, Santa Ana River, California The Santa Ana River stretches approximately 96 miles (154 kilometers) from its headwaters in the San Bernardino Mountains to its mouth at the Pacific Ocean near Huntington Beach, flowing through high desert and dense urban development in San Bernardino, Riverside, and Orange Counties. Native fish, also known as indigenous fish...
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.