California Water Science Center


The California Water Science Center has adjusted activities in response to guidance concerning the global COVID-19 pandemic. We will carry on the work of the USGS, while also maintaining the health and safety of our employees and community.  Based on direction from the White House, the CDC, and state and local authorities, we are shifting to a virtual mode. 

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Water Research Projects

Water Research Projects

Over 100 research projects addressing California's key water issues including: long-term water supply and availability, water quality, droughts and floods, climate change, aquatic ecology, the Delta, management of watersheds and groundwater.

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Partnering with Us

Partnering with Us

The USGS partners with local, state, and other federal agencies to provide scientific information needed by water-resources managers across the Nation.

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California Water Data

Basic hydrologic data collection, processing, analysis, dissemination, and archiving are major parts of the California Water Science Center program.

National Water Information System Mapper

Current California Streamflow Conditions

California Runoff

USGS WaterWatch

USGS Flood Event Viewer

California Post-Fire Debris-Flow Maps

California Water-Quality Mapper

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Date published: September 17, 2021

Public notice for the upgrade and expansion of the water monitoring network in the Sacramento-San Joaquin Delta

The U.S. Geological Survey (USGS) provided the public an opportunity  to review and comment on an Environmental Assessment (EA) for the construction, upgrade, and maintenance of new and existing monitoring stations in the Sacramento-San Joaquin Delta (Delta). Public...

Date published: September 16, 2021

USGS Scientists Compare Analytical Methods for the Analysis of Imidacloprid in Biological Matrices

In a recent research project, California Water Science Center scientists compared analytical techniques for the analysis of imidacloprid in biological matrices.

Date published: September 1, 2021

Increased Pumping in California’s Central Valley During Drought Worsens Groundwater Quality

SACRAMENTO, Calif. – Intensive pumping of aquifers during drought can speed up deterioration of groundwater quality, according to a new study by the U.S. Geological Survey. The results highlight clean drinking water supply vulnerabilities in California and other western states currently experiencing record drought conditions.


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Year Published: 2022

Evaluation of ELISA for the analysis of imidacloprid in biological matrices: Cross-reactivities, matrix interferences, and comparison to LC-MS/MS

Imidacloprid is among the most used pesticides worldwide and there are toxicity concerns for nontarget organisms. Accurate and sensitive methods are necessary to quantitate imidacloprid concentrations in biological matrices to better understand their fate and effects. Here we evaluated an enzyme-linked immunosorbent assay (ELISA) kit for...

Gross, Michael S.; Woodward, Emily; Hladik, Michelle

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Year Published: 2021

Precipitation-runoff processes in the Merced River Basin, Central California, with prospects for streamflow predictability, water years 1952–2013

The U.S. Geological Survey, in cooperation with the California Department of Water Resources (DWR), has constructed a new spatially detailed Precipitation-Runoff Modeling System (PRMS) model for the Merced River Basin, California, which is a tributary of the San Joaquin River in California. Operated through an Object User Interface (OUI) with...

Koczot, Kathryn M.; Risley, John C.; Gronberg, JoAnn M.; Donovan, John M.; McPherson, Kelly R.
Koczot, K.M., Risley, J.C., Gronberg, J.M., Donovan, J.M., and McPherson, K.R., 2021, Precipitation-runoff processes in the Merced River Basin, Central California, with prospects for streamflow predictability, water years 1952–2013: U.S. Geological Survey Scientific Investigations Report 2020–5150, 61 p.,

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Year Published: 2021

Critical aquifer overdraft accelerates degradation of groundwater quality in California’s Central Valley during drought

Drought-induced pumpage has precipitated dramatic groundwater-level declines in California’s Central Valley over the past 30 years, but the impacts of aquifer overdraft on water quality are poorly understood. This study coupled over 160,000 measurements of nitrate from ∼6,000 public-supply wells with a 30-year reconstruction of groundwater levels...

Levy, Zeno; Jurgens, Bryant; Burow, Karen R.; Voss, Stefan; Faulkner, Kirsten; Arroyo-Lopez, Jose Alfredo; Fram, Miranda S.