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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 managing California's water resources.

News

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USGS provides easy access to Colorado River science with new online portal

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Physics to Fish

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USGS Supports Effort to Understand Impacts on Water Quality Caused by 2018 Camp Fire in Paradise, California

Publications

Evaluating the reliability of environmental concentration data to characterize exposure in environmental risk assessments

Environmental risk assessments often rely on measured concentrations in environmental matrices to characterize exposure of the population of interest—typically, humans, aquatic biota, or other wildlife. Yet, there is limited guidance available on how to report and evaluate exposure datasets for reliability and relevance, despite their importance to regulatory decision-making. This paper is the sec
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Michelle Hladik, Arjen Markus, Dennis R. Helsel, Lisa H. Nowell, Stefano Polesello, Heinz Rudel, Drew Szabo, Iain Wilson

Methods of analysis—Determination of pesticides in filtered water and suspended sediment using liquid chromatography- and gas chromatography-tandem mass spectrometry

The widespread application of pesticides in agricultural and urban areas leads to their presence in surface waters. Presence of these biologically active chemicals in environmental waters potentially has adverse effects on nontarget organisms. To better understand the environmental fate of these contaminants, a robust method to capture chemicals with wide-ranging physicochemical properties has bee
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Michael S. Gross, Corey J. Sanders, Matthew D. De Parsia, Michelle L. Hladik

Multigenerational, indirect exposure to pyrethroids demonstrates potential compensatory response and reduced toxicity at higher salinity in estuarine fish

Estuarine environments are critical to fish species and serve as nurseries for developing embryos and larvae. They also undergo daily fluctuations in salinity and act as filters for pollutants. Additionally, global climate change (GCC) is altering salinity regimes within estuarine systems through changes in precipitation and sea level rise. GCC is also likely to lead to an increased use of insecti
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Sara Hutton, Samreen Siddiqui, Emily Pedersen, Christopher Markgraf, Amelie Segarra, Michelle Hladik, Richard E Connon, Susanne M. Brander

Science

Bay-Delta Catchability Study

Addressing catchability bias in fish surveys with catch-ratios In the scientific study of fish, "catchability" refers to the probability that a fish will be captured by a particular fishing gear or method. It is a measure of how effectively a fishing gear or method can capture fish. Catch data refers to information about the quantity and species composition of fish. Catch data is used by...
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Bay-Delta Catchability Study

Addressing catchability bias in fish surveys with catch-ratios In the scientific study of fish, "catchability" refers to the probability that a fish will be captured by a particular fishing gear or method. It is a measure of how effectively a fishing gear or method can capture fish. Catch data refers to information about the quantity and species composition of fish. Catch data is used by...
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Santa Ana River Native Fish Study

Native Fish Population and Habitat Study, Santa Ana River, California The Santa Ana River, the largest river in Southern California, flows through diverse landscapes, from the high desert to urban and suburban areas in Orange, Riverside, and San Bernardino counties, stretching approximately 96 miles (154 km) from its headwaters in the San Bernardino Mountains to its mouth at the Pacific Ocean near...
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Santa Ana River Native Fish Study

Native Fish Population and Habitat Study, Santa Ana River, California The Santa Ana River, the largest river in Southern California, flows through diverse landscapes, from the high desert to urban and suburban areas in Orange, Riverside, and San Bernardino counties, stretching approximately 96 miles (154 km) from its headwaters in the San Bernardino Mountains to its mouth at the Pacific Ocean near...
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Culturally Prescribed Fire

Culturally prescribed burning has been long practiced by the Yurok Tribe for a variety of reasons. This study explores using culturally prescribed fire as a land management tool for increasing the resiliency of streams and watersheds.
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Culturally Prescribed Fire

Culturally prescribed burning has been long practiced by the Yurok Tribe for a variety of reasons. This study explores using culturally prescribed fire as a land management tool for increasing the resiliency of streams and watersheds.
Learn More