Water Quality

From 2007 to 2021, the U.S. Geological Survey (USGS) collaborated with the Nevada Bureau of Mines and Geology on evaluating the forms of arsenic in Nevada groundwater resources. A total of 190 groundwater samples were collected from wells and springs throughout Nevada. Concentrations of arsenic ranged from <1.6 to 2,408 micrograms per liter (µg/L); in most cases, arsenate was the dominant species...

Since the late 1980’s, the USGS has collected discharge, sediment, and water quality data at seven major drainages under the Lake Tahoe Interagency Monitoring Program (LTIMP). Recently, continuous, real-time measurements of turbidity were added to the LTIMP. These data can be combined with in situ, model simulations, and remotely-sensed datasets available from the USGS, National Aeronautics and...

High concentrations of phosphorus (P) and nitrogen (N) are responsible for excessive, or nuisance algal blooms in many ecosystems world-wide, and climate change is predicted to exacerbate the problem1,2. Excessive nutrients supplied to the nearshore zone of Lake Tahoe may have significant consequences to ecological communities, water clarity, and water quality. The nearshore zone represents the...

USGS Nevada Water Science Center (NVWSC) is sampling for Volatile Organic Compounds (VOCs) in 2019 in order to confirm previous data collection efforts at Lake Tahoe. The Tahoe Regional Planning Agency (TRPA) requested sampling in targeted locations and at times when petroleum constituents are most likely to be detected in the lake.

The Nevada Water Science Center (NVWSC) is increasing the spatial understanding of the distribution of arsenic and important geochemical information in groundwater resources near select water-supply wells in southern Carson Valley by collecting groundwater samples to complement the existing dataset (2006 – 2015).

The USGS Nevada Water Science Center (NVWSC), in partnership with the National Park Service (NPS), is evaluating and monitoring the basic water quality and sediment chemistry of two proposed refugia and three established habitats for the endangered Mohave Tui Chub over the course of the year. NVWSC will also compare and evaluate findings to U.S. Environmental Protection Agency screening levels and...

The USGS Nevada Water Science Center (NVWSC), in collaboration with the U.S. Environmental Protection Agency (EPA), monitored mercury in the Carson River from 1997 to 2013. To preserve this long-term dataset, NVWSC is monitoring mercury concentrations and suspended sediment in the Carson River above and below Lahontan Reservoir. NVWSC also is beginning process-based sampling above and below...

The USGS National Water-Quality Assessment Project (NAWQA) is now part of the USGS National Water-Quality Program (NWQP). NAWQA provides nationally consistent data and information on the quality of the Nation’s water. Studies provide information on current water-quality conditions, a baseline for trend evaluation, and an understanding of what factors affect water quality. Groundwater studies for...

Water quality in the Lake Mead National Recreation Area (LAKE), particularly Las Vegas Bay, is affected by water coming from the Las Vegas Wash, an urban perennial stream whose water is comprised of treated wastewater and urban runoff coming from the Las Vegas metropolitan area. Common carp collected from Las Vegas Wash and Las Vegas Bay and largemouth bass collected from Las Vegas Bay have...

The Colorado River is one of the most intensely used rivers in the western United States, providing recreational watercraft activities and domestic drinking, industrial, and irrigation water for over 22 million users in the desert southwest. The quality of this water must be maintained to guarantee a reliable and safe resource for its many uses. The Colorado River provides an estimated 97 percent...

Periphyton, a type of algae, is growing on bottom sediment and rocks along nearshore areas of Lake Tahoe. Periphyton is seen as a nuisance and negatively impacts the recreational value of the lake. Periphyton biomass (PB) data collected along the nearshore of Lake Tahoe exhibit increasing trends over the last decade. However, the mechanisms that have caused these changes are not well understood.

The ecosystems of Stillwater National Wildlife Refuge (SNWR) are critical habitat for migratory birds. Increased irrigation efficiencies have reduced the amount of fresh water delivered to the wetlands, leading Congress to include provisions in the 1990 Truckee-Carson-Pyramid Lake Water Rights Settlement Act to assist with wetland restoration and maintenance. The Secretary of the Interior has...