CALIFORNIA/NEVADA: LAKE TAHOE Interstate Effort Protects Lake Tahoe from Contamination Background Location: The Lake Tahoe Basin borders both California and Nevada, between the Sierra Nevada crest and the Carson Range. The lake itself is 22 miles long and 12 miles wide, and is the tenth deepest lake in the world. Water Supply: 50 public water systems including 8 large scale public water systems (1 ground water) and 42 small scale (less than 200 households) public water systems. There are numerous private intakes to the lake or ground water withdrawals as well. Source Water Assessment: The Nevada Bureau of Health Protection (now Nevada Division of Environmental Protection-Water Bureau) and California Department of Health Services completed state source water assessments (SWAs) for Lake Tahoe in 2003. The Tahoe Regional Planning Agency (TRPA) developed a Lake Tahoe Source Water Protection Program in 2000 in order to coordinate protection activities and utilize information generated in the state SWAs. Priority Contamination Threats Major threats to the Lake Tahoe Basin water supplies include contaminants such as methyl tertiary-butyl ether (MTBE), other fuel constituents, used motor oil, turbidity, microbial pathogens, nutrients and hazardous wastes. Specific source contaminants include leaking underground storage tanks (LUSTs), gasoline spills, emissions, urban runoff, forest practices, road sanding, grading, dredging, shoreline erosion, stream diversions, domestic animal raising, waterborne recreational activities, wastewater infrastructure, septic systems, fertilizers, wood smoke and hazardous waste sites. Local Team and Develop the Protection Plan The Tahoe Water Suppliers Association (TWSA) is emerging as a leader in source water protection within the Lake Tahoe basin. TWSA, officially formed in 2003, traces its origins back to the late 1980's when the surface water agencies around the Lake began working together to understand the Surface Water Treatment Rule promulgated by the 1986 Safe Drinking Water Act (SDWA). TWSA consists of a majority of the area water suppliers: Edgewood Water Company, Kingsbury General Improvement District, Round Hill General Improvement District, Douglas County Utilities (Zephyr Cove, Skyland and Cave Rock), Glenbrook Water Company, Incline Village General Improvement District, Tahoe City Public Utility District, North Tahoe Public Utilities District and Lakeside Park Association. South Tahoe Public Utility District joined as an associate member in 2008. TWSA and its members developed a watershed control plan that is described in the following "Management Measures". Office of Water (4606M) 816F10005 January 2010 ------- Management Measures TWSA is a united voice advocating the protection of Lake Tahoe from contaminants that are potentially harmful to our health. Source water controls go further than the efforts of the Tahoe Regional Planning Agency and other regulatory agencies primarily focus on the world-renowned lake clarity. TWSA members have long acknowledged that the regulatory environment imposed by the TRPA has been essential in protecting the watershed as a drinking water source but now recognized it is time to go further. Sharing similar challenges, TWSA allows its members to combine forces to address federal and state guidelines established to protect the public from disease. Together they have created a watershed control plan with common standards and objectives while addressing the specific challenges that reside within each purveyor's territory and surrounding watersheds. The watershed control plan includes comprehensive data and analysis steps, education tools, and mapping. As a condition of the exemption to filtration granted to six of the purveyors, watershed plans are assessed yearly and updated every five years. The association maintains an active outreach program advocating water quality protection and an appreciation for municipal drinking water. Recent campaigns include: "Protect the Source", (general watershed protection), "Drink Tahoe Tap" (quality and value of municipal water) and "They Drop It, You Drink It" (pet feces awareness). Contingency Planning The completion of Phase 1 of a Risk Assessment Modeling Tool, being developed by Black & and Veatch, is anticipated in fall 2008. This project, funded by USAGE and TWSA, will provide Tahoe water purveyors with a real time analysis tool to evaluate potential risks to the drinking water intakes from shorezone development and activity. Measuring Program Results N/A For further information, contact: Madonna Dunbar Tahoe Water Suppliers Association (775) 832-1284 tahoeh20.org Office of Water (4606M) 816F10005 January 2010 ------- |