Water Quality

The overall project objective is to further our understanding of the link between nitrogen and phytoplankton dynamics in the Sacramento River and to elucidate effects of wastewater treatment plant effluent on food web dynamics.

The proposed study is designed to better establish relationships between patterns of delta smelt abundance and properties of suspended particles as measured by optical and acoustical techniques.

Tidal marshes provide animal habitats and prevent erosion. Expanding towns and cities have claimed major parts of San Francisco Bay’s marshland. Sediment deposits are essential to rebuilding tidal marshes and keeping existing marshes intact. In the southern part of the Bay, the largest tidal wetland restoration project on the west coast is underway. Sediment flux measurements are key in deciding...

During the past 25 years, industry and government made large financial investments in pollution control that have resulted in better water quality across the Nation; however, many water-quality problems remain. To address the need for consistent and scientifically sound information for managing the Nation's water resources the U.S. Geological Survey began a full-scale National Water-Quality...

The Bureau of Land Management (BLM) manages the Dos Palmas Oasis complex on the northeastern side of the Salton Sea for the maintainence of threatened and endangered species. This Oasis complex represents a rare area of riparian/wetland habitat in the midst of an extremely arid desert region. Anthropogenic development of water resources during the 1900s depleted natural groundwater supplies...

The Rim Fire has burned over 400 square miles of the Tuolumne River and Merced River watersheds in central California and is now the 3rd largest wildfire in state history. The burn area is largely on the Tuolumne between Hetch Hetchy Reservoir and Don Pedro Reservoir, both of which serve as critical sources of drinking water and irrigation water to San Francisco Bay area and Central Valley...

The Tulare Lake basin in the southern Central Valley of California is heavily dependent upon groundwater for drinking water supply but groundwater in this basin is threatened by a wide array of issues. Groundwater aquifers in the alluvial fan sediments derived from the Sierra Nevada on the eastern side of the Tulare Lake basin are highly productive aquifers that are vulnerable to contamination...

Pesticides are used throughout the State of California in both urban and agricultural settings and are routinely detected in surface water. Each year, new pesticides are introduced to the market and often become detected in surface water. It can take several years or more for routine monitoring programs to acquire the capability to detect new and understudied pesticides of concern because...

Runoff from snowmelt and rainfall in the Tuolumne River basin plays a significant role in irrigation and domestic water supply for Turlock and Modesto Irrigation Districts, City of Modesto and the San Francisco Bay Area. This area experiences very different seasonal and decadal climate events which are known to affect the timing and volumes of runoff. Land-cover change alone, such as the Rim Fire...

The atmosphere plays an important role in the delivery to and cycling of mercury (Hg) in the environment and it can be a major source of Hg contamination to surface waters. Globally, atmospheric deposition of Hg is the primary source of Hg related concerns for human and ecosystem health (Fitzgerald and others, 1998). In California and other areas in the United States, Hg use in gold and silver...

Extensive mercury use during historical gold processing has resulted in widespread mercury contamination and bioaccumulation of methylmercury in watersheds in the northwestern Sierra Nevada (Slotton and others 1997; Alpers and Hunerlach, 2000). A recent USGS report (May and others, 2000) documented the presence of elevated mercury in fish tissues in five reservoirs in the Bear River, Deer Creek...

Between 1956 and 1972, the Stringfellow Hazardous Waste Site, Riverside County, Calif., discharged approximately 34 million gallons of industrial wastes to unlined surface impoundments located at the head of Pyrite Canyon. Contaminants from the site have been detected as far as 4 miles downgradient near the Santa Ana River. Perchlorate in excess of the California Maximum Contaminant Level of 6...