Nevada Water Science Center

Lake Tahoe Tributary Monitoring

The Lake Tahoe Interagency Monitoring Program (LTIMP) is an essential part of integrated
science in the Lake Tahoe Basin and has provided long-term, consistent, reliable, and accessible
tributary monitoring data.

Research Plan

Collect and disseminate long-term water-quality and streamflow data on tributary streams to Lake Tahoe to:

  • provide a long-term database for estimation of sediment and nutrient loads and trends from major tributary streams and minor tributaries of undisturbed basins,
  • support assessment of the effects of land use and development on tributary loadings, and
  • provide stream water-quality data in support of basic research.


Deteriorating water quality and clarity in Lake Tahoe prompted the initiation of environmental programs in the Lake Tahoe basin. Water-quality data, especially nutrient and sediment data, for streams and ground-water aquifers that discharge to Lake Tahoe are needed to document the local and regional effectiveness of environmental programs and to assure compliance with California and Nevada water-quality management programs. The data is needed to determine long-term trends in nutrient and sediment concentrations and loads in streams. A well-designed monitoring program is needed to determine the role of groundwater in the nutrient budget of Lake Tahoe.

The monitoring program as it currently exists, began in 1988 as a cooperative program between the USGS, Tahoe Regional planning Agency, and the University of California, Davis principally to address the contributions of sediment and nutrient (nitrogen and phosphorus) loading to the lake from tributaries. Since 1988, the USGS, Tahoe Regional planning Agency, and University of California, Davis have spent more than $12 million on the tributary monitoring program and collected over 11,000 water-quality samples, with in-kind services provided by the University of California, Davis Tahoe Environmental Research Center.


A complete list of USGS Nevada Water Science Center Lake Tahoe publications: Lake Tahoe Bibliography (PDF)


Quick Facts


Location: Lake Tahoe Basin, Western Nevada

Start Date: 1988

End Date: ongoing

Cooperators:Tahoe Regional Planning Agency, U.S. Forest Service

Contact Information


Nancy Alvarez

USGS Nevada Water Science Center

2730 N. Deer Run Rd.

Carson City, NV 89701

phone: (775) 887-7644



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