CWES

Center for Watersheds and Environmental Sustainability

Projects: Lake Tahoe Projects · Walker Lake Watershed Projects · Other Watershed Projects

Projects: Lake Tahoe Watershed

Picture by Alan Heyvaert

Image courtesy of Jim Thomas

Image courtesy of Alan Heyvaert

Image courtesy of Alan Heyvaert

Since it’s inception in 1999, CWES faculty have been or currently are involved in more than 40 research projects in the Lake Tahoe basin. Algal growth and fine sediment entering the lake have produced an average 1-foot per year decline in lake clarity since the 1960s. For this reason, the majority of CWES projects have focused on identifying the sources and amounts of nutrients (nitrogen and phosphorus), which trigger algal growth, and fine (< 10 micron) sediment and the processes by which they enter the lake, and how best to remove them from runoff entering the lake. Erosion control and sediment and nutrient removal projects are known as best management practices (BMPs). BMPs in the Lake Tahoe basin range from constructed wetlands to highway sediment capture and nutrient removal structures. Some of the CWES related projects that deal with nutrient and fine sediment loading to Lake Tahoe and the health of the watershed include:

• Identifying atmospheric sources of dust and nutrients in the Tahoe basin
• Determining atmospheric dust and nutrient deposition rates on the lake surface
• Measuring and modeling fugitive dust emissions from roads in the basin
• Characterizing stormwater runoff fine sediment and nutrient loads
• Evaluating nutrient and fine sediment loading for different land uses
• Determining groundwater nutrient loading to the lake
• Conducting near-shore lake clarity surveys to identify areas of high nutrient and fine sediment loading from surface water, stormwater, and groundwater inflows
• Determining shoreline erosion contributions of fine sediment and nutrients to the lake
• Identifying and quantifying microbiological communities in the lake
• Evaluating restoration project effectiveness in removing fine sediment and nutrients from surface water runoff
• Evaluating BMP structures effectiveness in removing fine sediment and nutrients from surface water runoff
• Determining the amount of impervious cover, such as roads, parking lots, and roofs, that produced increased stormwater runoff in the Lake Tahoe watershed
• Evaluating the effects of fire on atmospheric sources of nutrients entering the lake
• Identifying the sources of fine sediment that enter the lake
• Developing bio-engineer systems for removal for nutrients and fine sediment in stormwater runoff
• Evaluating the efficiency of highway runoff structures for removal of nutrient and fine sediment
• Evaluating the health of the American Martin population in the watershed
• Help structure adaptive management, so that as new information is gained in the basin management practices can include this information
• Develop a stormwater monitoring program for the Lake Tahoe watershed

CWES has helped organize numerous workshops and conferences in the basin to disseminate scientific information to land management and regulatory agencies needed for policy decisions. For example, recent workshops include the 4th Biennial Tahoe Basin Science Conference, March 17-19, 2008; the Science as a Tool in Lake Tahoe Basin Management—Lake Tahoe Science Plan Workshop, October 18-20, 2006; the 2nd Biennial Conference on Tahoe Environmental Concerns—Research as a Tool for Tahoe Basin Issues, May 17-19, 2004; and Using Science as a Tool in Restoration and Water Quality Management in the Tahoe Basin—Lake Tahoe Higher Education and Research Symposium, May 13-14, 2002.

DRI is a charter member of the Tahoe Science Consortium (TSC: http://www.tahoescience.org). The TSC consists of five research institutions--the Desert Research Institute, University of California Davis, University of Nevada Reno, U.S. Geological Survey, and the Pacific Southwest Research group of the U.S. Forest Service--and 10 land management and regulatory agencies. The TSC brings scientists and land management and regulatory agencies together to share scientific information needed for restoration and BMP projects and policy and regulatory decisions in the basin. The TSC drafted the Lake Tahoe Science Plan, which will be the foundation for future research directions and funding in the basin. CWES was instrumental in helping to develop the working agreement that directed $37.5 million per year of SNPLMA monies to the Lake Tahoe basin for restoration activities. Approximately $3.5 million per year (a total of $28 million over 8 years) of the Tahoe SNPLMA funding will be used to fund research activities in the Tahoe basin. CWES, along with other academic institutions and several federal, state, and local agencies, was instrumental in developing the TSC, which provides science and research input to management, planning, and restoration efforts in the Tahoe basin. The TSC was launched in August 2005.

Available Report(s)

DRI Lake Tahoe Source Characterization Study: Final Report (PDF)

Journal of the Nevada Water Resources Association, Fall 2004 (PDF)

Measurement and Modeling of Fugitive Dust Emissions from Paved Road and Travel in the Lake Tahoe Basin (PDF)

Nutrient and Sediment Production, Watershed Characteristics, and Land Use in the Tahoe Basin, California-Nevaa (PDF on WILEY InterScience)