California Water Science Center

Water Quality

Filter Total Items: 127
Date published: September 28, 2020
Status: Completed

Sediment transport, streamflow, and climate change: long-term resilience of the Bay-Delta

Sediment supply is important to the health of the Sacramento-San Joaquin River Delta and San Francisco Bay (Bay-Delta) ecosystem. Sediment eroded from upland source areas in the Sacramento and San Joaquin watersheds is transported through the rivers to the Bay-Delta where it is deposited in mudflats and tidal wetlands, which in turn helps protect against the effects of sea-level rise. Sediment...

Date published: August 26, 2020
Status: Active

High Resolution Temporal and Spatial Mapping of Mercury and Methylmercury in Surface Waters of the Sacramento – San Joaquin Delta

Mercury (Hg) is a contaminant of significant concern in the San Francisco Bay-Delta estuary and watershed (Bay-Delta). The formation, fate, and transport of methylmercury (MeHg), a particularly toxic organic form of Hg that readily bioaccumulates in wildlife, has been studied extensively throughout the system. However, there is widespread recognition of the need for more comprehensive...

Date published: August 5, 2020
Status: Active

Evaluating the effects of wastewater-derived nutrients on phytoplankton abundance and community structure in the San Francisco Estuary and Delta

Planned upgrades to the Sacramento Regional wastewater treatment plant (SRWTP) will substantially reduce nutrient discharge and also alter the types and amounts of nutrients being distributed across the San Francisco Delta and Estuary (Delta).

One highly anticipated outcome of lower nutrients is improved productivity in the phytoplankton communities that supply aquatic food webs, which...

Date published: July 15, 2020
Status: Active

Modeling Nitrogen Reduction Benefit to Invasive Aquatic Vegetation vs. Native Phytoplankton

Phytoplankton comprise the bottom of the aquatic food web and the abundance of phytoplankton serves as an indicator of healthy aquatic habitats. In the Sacramento-San Joaquin River Delta (Delta), competing with phytoplankton for required nitrogen, invasive aquatic vegetation (IAV) has increased exponentially in recent years. Once established, IAV can negatively impact local ecosystems and...

Date published: June 30, 2020
Status: Active

Hydrogeological Evaluation of the Edwards Air Force Base Air Force Research Laboratory Area and the North Muroc Groundwater Subbasin, Antelope Valley, California

In cooperation with Air Force Civil Engineer Center (AFCEC), the U.S. Geological Survey (USGS) is evaluating the hydrogeology of the Air Force Research Laboratory (AFRL) and Site 25 areas of Edwards Air Force Base (EAFB) and the adjacent North-Muroc groundwater subbasin to help determine regional groundwater movement and the possible long-term movement and pathways of contaminated...

Contacts: Nicole C Fenton
Date published: June 26, 2020
Status: Active

Monitoring Cyanotoxins in California's Sacramento-San Joaquin Delta: Fixed Stations and High-Resolution Mapping Surveys

California’s Sacramento-San Joaquin River Delta (Delta) provides drinking water to about 30 million people and irrigation water to the agriculturally rich Central Valley. The Delta is also home to numerous threatened and endangered native species. The health of the Delta's aquatic ecosystems, and fish in particular, have long been in a state of decline. This is associated with decreasing...

Date published: August 27, 2019
Status: Active

Mercury studies at Sulphur Bank Mercury Mine and Clear Lake, California

The abandoned Sulphur Bank Mercury Mine on the shores of Clear Lake in Northern California has been designated as a "Superfund Site" by the U.S. Environmental Protection Agency (EPA). This means that the EPA has determined that the area is contaminated by hazardous waste and requires cleanup...

Date published: July 24, 2019
Status: Active

Organic Matter Research Laboratory

The USGS California Water Science Center's Organic Matter Research Laboratory provides laboratory services and support to regional and national projects in the analysis of organic matter using the latest methods in absorbance and fluorescence spectroscopy along with standard measurement of total dissolved organic carbon and nitrogen concentration.

Date published: June 4, 2019
Status: Completed

Examining Erosion at Malakoff Diggins State Historic Park, a Sierra Nevada Gold Mine

Located in Nevada County, California, Malakoff Diggins State Historic Park was the Sierra Nevada’s largest hydraulic gold mine, operating from 1866 to 1884. Historically, part of the process of hydraulic mining included using mercury to extract gold from produced sediment through the process of amalgamation. This process left thousands of pounds of mercury and other heavy metals in the area....

Date published: June 4, 2019
Status: Active

Developing Spatial Data on Mineral Deposits Found on Abandoned Mine Lands

Better understanding of mineral deposits and their impact on the environment, including the water system, is necessary for the protection of public health. The USGS is working with other federal and state agencies to identify the environmental behavior of these deposits and their waste products. USGS scientists are using geospatial data (data that can be mapped) to prioritize abandoned mine...

Date published: May 16, 2019
Status: Active

San Diego Hydrogeology

This is the first comprehensive geologic and hydrologic study for the San Diego area. This study will provide the integrated hydrogeologic knowledge necessary in this important and highly visible area of the United States and will serve as a role model for similar coastal settings throughout the world that have modest rainfall and small aquifers. Locally, results will help...

Contacts: Wesley Danskin
Date published: May 2, 2019
Status: Active

Groundwater Ambient Monitoring & Assessment (GAMA)

The Groundwater Ambient Monitoring and Assessment Program’s Priority Basin Project (GAMA-PBP) was established by the California State Water Resources Control Board (SWRCB) in response to the Ground-Water Quality Monitoring Act of 2001 (Sections 10780-10782.3 of the California Water Code). The USGS is the technical lead for the GAMA-PBP and between 2004-2012 focused on characterizing the...

Contacts: Miranda Fram