Lake Tahoe Tributary Monitoring

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 ground water in the nutrient budget of Lake Tahoe.

The stream and ground-water monitoring are part of the Lake Tahoe Interagency Monitoring Program (LTIMP), an essential part of science in the Lake Tahoe Basin. LTIMP provides long-term, consistent, reliable, and accessible stream and ground-water data. LTIMP stream monitoring began in 1979 and the current monitoring program, conducted by USGS, began in 1988.

Objectives

Collect and disseminate long-term water-quality and streamflow data on tributary streams to Lake Tahoe to support science-based environmental planning, management, and regulatory decisions. Other objectives include (1) providing a long-term database for estimation of sediment and nutrient loads and trends from major tributary streams and minor tributaries of undisturbed basins, (2) supporting assessment of the effects of land use and development on tributary loadings, (3) providing stream water-quality data in support of basic research, and (4) providing a long-term ground-water database.

Strategy and Approach

A hydrologic data-collection network on Lake Tahoe tributary streams that drain representative land-use and development areas in the basin will be operated. Continuous-record streamflow data will be used in conjunction with instantaneous nutrient and suspended sediment concentration data to estimate the loads of nutrients, and suspended sediment. Ground-water monitoring was discontinued in 2004 due to lack of funding.

Relevance and Benefits

An important part of the USGS mission is to provide scientific information to manage the water resources of the Nation. To effectively assess the Nation's surface-water resources, and ground-water resources, the USGS collects water-quality data from lakes, streams, estuaries, and ground-water aquifers using standardized methods, and maintains the data from these stations in a national data base. These data also are published in annual data reports, and increasing amount of real-time and historical water-quality data are available on the World Wide Web. Long-term water-quality data characterize the physical, chemical, and biological changes in our water resources in response to natural resources including climatic variations, storms, floods, droughts, and a variety of human activities that exert an influence on water-quality conditions. The data are useful in designing programs to protect watersheds, sensitive aquatic habitats, biota, and drinking water sources from urban runoff, sewage, and industrial wastes. The data also are useful in designing programs to maintain water clarity , aesthetics, contact recreation and to meet the President's Initiatives at Lake Tahoe. The water-quality data collected in Nevada are an integral part of the nationwide water-quality data program.

Recent Publications

Publications which were recently released are listed below. A complete list of USGS Nevada Water Science Center Lake Tahoe publications, including additional publications from this project, is also available: Lake Tahoe Bibliography (PDF)

Allander, K.K., 2007, Update on the effect of a large wildfire on stream-nutrient concentrations within an undisturbed watershed in the Lake Tahoe Basin: USGS poster

Allander, K.K., 2006, Update on the effect of a large uncontrolled wildfire on stream-nutrient concentrations within an undisturbed watershed in the Lake Tahoe Basin: Journal of the Nevada Water Resources Association, Special Lake Tahoe edition, v. 4, no. 1, p. 21

Alvarez, N.L., Preissler, A.M., Hackley, S.H., and Arneson, P.A., 2006, Lake Tahoe Interagency Monitoring Program--An integral part of science in the Lake Tahoe Basin: Journal of the Nevada Water Resources Association, Special Lake Tahoe edition, v. 4, no. 1, p. 38

Allander, K.K., 2005, Ground-Water Reconnaissance of the Bijou Creek Watershed, South Lake Tahoe, California, June-October 2003: U.S. Geological Survey Open-File Report 2005-1329, 34 p.

Rowe, T.G., Halsing, David, Raines, G.L., Thacker, A.M., and Watermolen, S.C., 2005, USGS Activities in the Lake Tahoe Basin: U.S. Geological Survey Fact Sheet 2005-3047, 2 p.

Allander, K.K., 2003, Trout Creek--Evaluating ground-water and surface-water exchange along an alpine stream, Lake Tahoe, California, in Stonestrom, D.A., and Constantz, Jim, eds., Heat as a tool for studying the movement of ground-water near streams: U.S. Geological Survey Circular 1260, p. 35-45

Rowe, T.G., Saleh, D.K., Watkins, S.A., and Kratzer, C.R., 2002, Streamflow and water-quality data for selected watersheds in the Lake Tahoe Basin, California and Nevada, through September 1998: U.S. Geological Survey Water-Resources Investigations Report 02-4030, 118 p.

Rowe, T.G., 2000, Lake Tahoe Interagency Monitoring Program—Tributary sampling design, sites, and periods of record: U.S. Geological Survey Fact Sheet 138-00, 4 p.

Boughton, C.J., Rowe, T.G., Allander, K.K., and Robledo, A.R., 1997, Stream and ground-water monitoring program, Lake Tahoe Basin, Nevada and California: U.S. Geological Survey Fact Sheet FS-100-97, 6 p.