Interstate Effort Protects Lake Tahoe from


   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
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
   For further information, contact:
   Madonna Dunbar
   Tahoe Water Suppliers Association
   (775) 832-1284
Office of Water (4606M)                       816F10005                              January 2010