Water Quality in the Las Vegas Valley Area and Carson and Truckee River Basins, Nevada and California, 1992-96

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Map showing the location of
 the study unit basins in Nevada and California This report summarizes the major findings of the National Water-Quality Assessment (NAWQA) Program for the Las Vegas Valley area and the Carson and Truckee River Basins in Nevada and California. These areas are the Nevada Basin and Range (NVBR) NAWQA Study Unit. The statements on major findings below are expanded in the section on Major Issues and Findings of this report. Comparisons of data for this Study Unit with data from all 20 NAWQA Study Unit investigations that began in 1991 are presented in the section on Water-Quality Conditions in a National Context. Although this report is part of a national program, it also is intended as a resource for anyone interested in water-quality conditions in the NVBR Study Unit. 

Geology and Climate Have Caused High Concentrations of Dissolved Solids, Arsenic, Uranium, and Radon in Some Areas

Some water-quality criteria have been exceeded in the NVBR Study Unit because of natural factors (p. 9-11).

Urban Activities Have Been Primary Sources of Nutrients, Synthetic Organic Compounds, and Trace Elements

Nutrients can enter water resources by discharge of treated sewage, leaking sewer pipes, domestic septic systems, and fertilizer applications (p. 12, 13, and 18). Many pesticides were detected at low levels in water resources of urban areas (p. 13 and 18). Volatile organic compounds (VOCs) were commonly detected at low levels in urban areas (p. 13 and 18). Trace elements and semivolatile organic compounds (SVOCs) were enriched in bottom sediment downstream from urban areas (p. 14-17 and 27).

Agricultural Activities Have Contributed Dissolved Solids, Trace Elements, Nutrients, and Pesticides

Agricultural areas have contributed irrigation drainage and nutrients to water resources (p. 19-21). Pesticides were present at low levels, less than the MCLs, in agricultural areas (p. 22).

Urban and Agricultural Activities Have Affected Water Resources Differently

Urban and agricultural activities contribute different nutrients, pesticides, and trace elements to water resources, but VOCs and semivolatile organic compounds are signatures of urban activities (p. 12-22).

Historical Mining Activities Have Released Trace Elements to the Carson River

Trace elements were enriched in Carson River bottom sediment downstream from historical mining activities of the Leviathan Mine and the Comstock Lode (p. 23-24).

U.S. Geological Survey Circular 1170

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Suggested citation:
Bevans, H.E., Lico, M.S., and Lawrence, S.J., 1998, Water Quality in the Las Vegas Valley Area and the Carson and Truckee River Basins, Nevada and California, 1992-96, on line at <URL:>, updated 19 March 1998

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Last modified: Wed Mar 18 10:50:48 1998