Water Quality

Pyrethroid insecticide use in California has been increasing in recent years. Pyrethroids are used in both agricultural and urban areas. They are of environmental concern because of their high toxicity to fish and invertebrates.

The primary purpose of the USGS portion of this proposed study is to evaluate if spectrophotometric and spectrofluorometric methods are useful for identifying organic sources of oxygen demand by analyzing water-quality samples (DO, BOD, Chl, SSC, Salinity, THg, MeHg) collected by other agencies and project participants. Sources to be evaluated include algal production, vegetation, soils, and...

The goals of the BLM suction dredging treatability study are to (1) assess the effectiveness of suction dredging in removing mercury from the environment and (2) assess potential impacts of suction dredging with regard to discharging mercury-contaminated suspended sediment to the aquatic environment.

The Sacramento-San Joaquin Delta (Delta) is home to a diverse community of plants and animals and is the hub of California’s freshwater delivery system. The Delta supplies water for over 25 million Californians and supports millions of acres of farming, commercial and sport fishing, shipping and ports, and recreational boating.

San Gorgonio Pass Water Agency (SGPWA) covers an area of 220 square miles in the mountain pass between the Upper Santa Ana River Basin to the west and the Coachella Valley to the east. Since 1961, when the SGPWA was formed, demand for ground water has increased with the increase in population within the agency boundaries. To prepare for future demands for water, the SGPWA has proposed to...

Between 1860 and 1914, hydraulic mining activities sent more than 800,000,000 cubic yards of mercury-laden sediment into the Delta altering the landscape, water flows, and contributing to the leveeing and reclamation of the Delta's marshes. Transport of mercury from historic mining areas continues today. The sedimentary supply of mercury to the Delta and in Delta sediments (cinnabar, metacinnabar...

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 the amount and source of the DOC, both of which...

Using the new information, along with the recently acquired seismic reflection data, USGS scientists and co-workers have been able to develop a much more detailed understanding of the stratigraphy and structure of the Central and West Coast Basins.

The Mountains Recreation and Conservation Authority (MRCA) is considering plans for developing a new park at the confluence of the Los Angeles River and the Arroyo Seco. These plans include removing channel lining and creating a temporary lake using an inflatable rubber dam. Before implementing the plan, a wide array of scientific and engineering issues must be addressed. The U.S. Geological...

The San Francisco Bay and Sacramento-San Joaquin Delta (Bay-Delta) region is a highly urbanized and contaminated estuary with a valuable commercial and recreational fishery (Nichlos et al., 1986; SFEI, 2004). Many fish and birds in the San Francisco Estuary exhibit high levels of contaminants (metals and organic pollutants), which have been shown to affect their behavior and reproductive success...

The Hi Desert Water District (HDWD) provides water service to about 10,000 customers in the areas of Yucca Valley, Yucca Mesa, and some unincorporated areas of San Bernardino County. The study area is the 19 square mile Warren subbasin of the Morongo groundwater basin (approximately 100 miles east of Los Angeles, California).

Mercury is a rare, dense metal, slightly more common than gold in the earth's crust. Mercury occurs in several different forms, the most important of which is methylmercury. Methylmercury is the form most readily incorporated into biological tissues and most toxic to humans. Methylmercury accumulates and biomagnifies in the food chain, reaching highest concentrations in predatory fish such as bass...