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Lake Tahoe Basin Science
For decades, the U.S. Geological Survey (USGS) has been a leader in a wide range of scientific research and monitoring activities in the Lake Tahoe Basin. Through this research, significant advances in understanding have been made about how sediment and nutrient sources affect water quality and clarity of Lake Tahoe.
Lake Tahoe is a beautiful Alpine Lake in the Sierra Nevada. Known for its deep, clear water, Lake Tahoe is the second deepest lake in the United States, with a maximum depth of 1,645 feet. The average depth of Lake Tahoe is 1,000 feet.
Since the late 1980’s, USGS has collected discharge, sediment, and water quality data at seven major drainages as part of the Lake Tahoe Interagency Monitoring Program (LTIMP) . Continuous, real-time measurements of turbidity recently were added to LTIMP sites. Similarly, the U.S. Department of Agriculture, National Resources Conservation Service (NRCS) has conducted continuous snowpack and soil monitoring in basin headwaters, with daily snow measurements dating back to the late 1970’s or early 1980’s at most sites. These data can be combined with remotely sensed datasets available from USGS and National Aeronautics and Space Administration NASA and analyzed to determine the key factors controlling measured fine sediment and nutrient load in LTIMP streams draining to Lake Tahoe.
Lake Tahoe Basin data can now be accessed through the Lake Tahoe Hydro Mapper. The Hydro Mapper is an interactive map viewer which allows users to see real-time information on stream flow discharge, stage, nutrient, turbidity, sediment loads, and storage data. Data from NRCS Snow Telemetry (SNOTEL), National Weather Service Advanced Hydrologic Prediction Service and other local and regional hydrologic data with weather radar, watershed extents, and other ancillary geospatial data are included.
In addition to the data available in the Hydro Mapper, hydrologic functioning of the seven LTIMP watersheds are be assessed by determining key hydrologic conditions that drive daily variability of instream water quality at daily, monthly, and annual time intervals. The drivers may be a combination of dynamic (e.g., snowpack level, antecedent soil moisture or temperature, meteorological conditions) and static (e.g., terrain, geology, soil/vegetation) conditions within each watershed as well as various urban impacts and best management practices. Data about these key hydrologic conditions are available through this website.