Bay-Delta

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...

Tidal marshes are important ecosystems in the San Francisco-Bay Delta. They remove carbon from the atmosphere, they build up soils that buffer our communities from sea level rise, they provide critical habitat and food resources for a diversity of species, and they reduce excessive nutrients which have a negative impact on water quality. As a result of land-use change and urbanization, the San...

To help emergency managers and others protect life and property due to floods and other water-related hazards, the USGS delivers a continuous source of streamflow information. The U.S. Geological Survey has been measuring streamflow in the U.S. for over 120 years. We operate more than 7,500 streamgages in the U.S. and nearly 500 in California that collect data to determine the amount of water...

At two priority locations on BLM-administered land in the Yuba River watershed, the USGS has documented relatively rapid erosion of river bank material that consists of mercury (Hg)-laden sediment with a significant component of mining debris.

The objectives of this specific study are to characterize the mixtures of current-use pesticides and pesticide degradates entering the Sacramento/San Joaquin Delta from its two main river sources over a period of 12 consecutive months.

The purpose of the proposed work is to collect data that will support the development, calibration, and validation of numerical models of sediment transport and turbidity in the Sacramento-San Joaquin Delta.

Mercury (Hg), a legacy pollutant from mining of mercury deposits in the Coast Ranges as well as gold deposits in the Sierra Nevada, has contaminated surface waters throughout northern California. Methylmercury (MeHg) is an organic form of Hg that bioaccumulates in food webs to elevated concentrations that threaten ecological health and human health through consumption of sport fish.

Suspended solids are an important component of San Francisco Bay, California (USA) because they transport adsorbed toxic substances, provide habitat for benthic organisms, limit light availability and photosynthesis, and deposit in ports and waterways which require dredging. The U.S. Geological Survey has established a network of eight sites in San Francisco Bay at which suspended-solids...

The U.S. Fish & Wildlife Service's (USFWS) San Francisco Bay National Wildlife Refuge manages wildlife at a number of salt ponds that the Cargill Corporation currently operates for salt production. A number of these ponds probably will be purchased by the USFWS. With acquisition, the USFWS will be responsible for maintenance or restoration of thousands of hectares of wetlands, an extremely complex...

Water from the Sacramento-San Joaquin Delta contains high concentrations of disinfection byproduct-forming (DBP-forming) materials when treated for potable use. DBPs form when dissolved organic compounds (DOC) in water react with disinfectants such as chlorine and ozone during the water treatment process. The amount of DBPs that form is a function of both the amount and source of the DOC, both of...

Sources and fate of various forms of organic carbon in the Sacramento-San Joaquin Delta (Delta) and San Joaquin River watershed are of concern because of the importance of identifying the sources of carbon contributing to the oxygen depletion zone on the San Joaquin River near the city of Stockton, the need to understand the causes of the low primary and secondary production in the Delta, and the...

Our group at the USGS continuously monitors suspended-sediment concentration (SSC), turbidity, dissolved oxygen, temperature, salinity, and water level at many sites throughout the San Francisco Bay (Bay) and the Sacramento-San Joaquin Rivers Delta (Delta). Our work began in 1988 to explore the spatial and temporal variability of water quality and sediment transport and to provide decision makers...