Science in the Truckee River Basin

Science Center Objects

The Truckee River flows for 120 miles from the outlet of Lake Tahoe in California, into Nevada, through the city of Reno, until it terminates at Pyramid Lake and is the only source of surface-water outflow from Lake Tahoe. The majority of the streamflow in the Truckee River comes from the Sierra Nevada snowpack. Contributions to the river in Nevada are small due to the Sierra Nevada’s “rain shadow effect” which limits annual precipitation in the Nevada part of the Truckee River basin to less than 10 inches per year. The Truckee River supplies water to a diverse group of water users: power generation, municipalities, industry, and agriculture as well as being the primary source of water for Pyramid Lake. The Truckee is critical to maintaining Pyramid Lake water levels and supporting the endangered cui-ui lakesucker and the threatened Lahontan cutthroat trout.

Map of the Truckee River Basin, Nevada and California

Map of the Truckee River Basin, Nevada and California. (Public domain.)

The Truckee River basin (hydrographic region 6) covers over 4,700 square miles and straddles the California-Nevada border. The Truckee River Basin includes the following hydrographic areas: Winnemucca Lake Valley, pyramid Lake Valley, Dodge Flat, Tracy Segment, Warm Springs Valley, Spanish Springs Valley, Sun Valley, Truckee Meadows, pleasant Valley, Washoe Valley, Lake Tahoe Basin, and the Truckee Canyon Segment. Major cities in the Truckee River Basin are Truckee, California, and Reno and Sparks, Nevada.

Conflicts regarding Truckee River water rights have been long-standing and intense among various economic, political, ecological, and institutional interests because the average-annual demand for water is greater than the supply. Water rights are fully or over-allocated with respect to annual water volumes. Diversions from the Truckee River, along with the arid desert enviroment, caused water levels in Pyramid Lake to drop more than 90 feet between 1891 and 1966. Water levels in Pyramid Lake have stabilized although they still fluctuate in response to hydrologic conditions.

One of the first large diversions of the Truckee River was authorized by the 1902 Reclamation Act for agricultural irrigation. Allocations of water from the Truckee River are now governed by the Truckee River Operating Agreement which is a major part of Public Law 101-618, the Truckee-Carson-Pyramid Lake Water Rights
Settlement Act of 1990.

USGS Nevada Water Science Center maintains more than 42 streamflow gages on the Truckee River.


Real-Time Streamflow :: Daily Values :: Peak-Flow:: Water Quality

Streamflow in the Truckee River compared to elevation of Pyramid Lake

Streamflow in the Truckee River compared to elevation of Pyramid Lake. (Public domain.)


Hydroclimatic-Socioecolgical Modeling Science

Water for the Seasons


Lake Tahoe Science

Lake Tahoe Tributary Monitoring

Lake Tahoe Water Quality Shorezone Monitoring

Nutrient Source Identification in Groundwater and Periphyton Along the Nearshore of Lake Tahoe

Quantifying watershed controls on fine sediment particles and nutrient loading to Lake Tahoe using data mining and machine learning


Water Availability and Use Science

Effects of Groundwater Withdrawals, Tracy Segment

Evaluating Artificial Storage and Recovery Potential of Bedell Flat, Washoe County, Nevada

Evaluation of water-level decline and aquifer properties in the Virginia City Highlands and Highland Ranches Volcanic Rock aquifer system, Storey County, Nevada


Lake Tahoe Nearshore Periphyton Study

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.

Visit the project web page: Lake Tahoe Nearshore Periphyton Study

If you would like information about other completed studies, please email the NVWSC at GS-W-NVpublic-info@