Water Division August 2017 75 Hawthorne Street, San Francisco, CA S4105 866-EPA-WEST • www.epa.gov/region9 v»EPA U.S. Environmental Protection Agency Pacific Southwest / Region 9 Sewing Arizona, California, Hawaii, Nevada, the Pacific Islands and 148 Tribes 21 Years of Investing in a Clear, Healthy Lake Tahoe Lake Tahoe is an EPA Priority Watershed, in part because of its iconic clarity and beauty But climate change and human disturbance of the watershed threaten this national treasure. Lake clarity recov- ered from the impacts of extensive logging in the 19th century but rapid, unregulated development following the 1960 Winter Olympics again increased fine sediment and nutrients flowing into the lake. Between 1968 and 1997, annual average clarity fell dramatically from around 100 feet to 64 feet (Figure 1). AVERAGE ANNUAL CLARITY (SECCHI DEPTH) 1965 1970 1975 1980 1985 1990 1995 2000 2005 2010 2015 YEAR Figure 1. Source: UCDavis TERC (terc.ucdavis.edu) A new era of ecosystem and watershed restoration began in 1997 with the visit of President Clinton to Lake Tahoe, where he helped launch the Environ- mental Improvement Program. This $2 billion effort has helped achieve Tahoe Basin improvements for air and water quality, soil conservation, forest health, wildlife and fisheries, and scenic and recre-ational resources. The decline in annual average lake clarity halted in recent years, reaching 78 feet in 2014, but decreasing back to 69 feet last year. Past improvements may be traced in part to local man-agement of urban runoff guided by innovative decision-making tools, as well as to less runoff from prolonged drought conditions. Continued progress as we face growing challenges of cli mate change, like increasing tree mortality, forest fires, and proliferation of invasive species, will require constant vigilance and dedicated resources. What Is EPA Doing to Protect Lake Tahoe? EPA has been charged with protection of the Tahoe Basin ever since Section 114 of the 1972 Clean Water Act required implementation of a study to ".. .preserve the fragile ecology of Lake Tahoe." EPAs involvement accelerated sharply after the 1997 Presidential Forum, where President Clinton announced a number of air- and water-quality goals, as well as a full-time, on-site EPA Lake Tahoe Basin Coordinator. Since then, EPA has invested over $47 million, including $9 million for a lake clarity restoration plan, known as a Total Maximum Daily Load (TMDL). EPA also oversees implementation of the Clean Water Act, Safe Drinking Water Act, Clean Air Act and other statutory requirements by our partner agencies in California and Nevada, and by local partners. What Is the Lake Tahoe Total Maximum Daily Load (TMDL) and What Does It Do? The Lake Tahoe TMDL is the centerpiece of EPAs efforts to reverse the decline in the lake's deep-water clarity and restore it to historic levels. The TMDL and its Implementation Plan were adopted by California and Nevada, and approved by EPA in 2011 following a 10-year, $10 million development effort funded by state and federal agencies. Both the scientific research and stakeholder input that under- pin the final restoration plan are among the most advanced ever applied to a TMDL in the Clean Water Act's 45-year history. Key elements include: • Understanding Pollutant Sources: Relative amounts of fine sediment, phosphorus and ------- nitrogen inputs to Lake Tahoe were quantified from major pollutant sources including urban and forest stormwater runoff, stream channel erosion, and atmospheric deposition. Targeting Load Reductions: Load reductions for the largest pollutant sources were quantified in order to achieve the interim "Clarity Challenge" target of 78 feet by 2026 and the long-term TMDL numeric clarity goal of 97 feet by 2076 (Figure 2). Load Reduction Milestones to meet TMDL Goal 2016 2021 2026 2031 2036 2041 2046 2051 2056 2061 2066 2071 2076 Years ~ Fine Sediment Particles sTotal Phosphorus 3Total Nitrogen Figure 2. Source: U.S. EPA • Creating and Implementing a Strategy: A strategy was developed to achieve pollutant load reductions through many possible actions, includ- ing improved roadway operations and mainte- nance, targeted street sweeping programs, infiltra- tion basins to capture and treat urban stormwater, stabilization and revegetation of eroding slopes, removal of impervious cover and restoration of soil infiltration, and numerous non-urban source control and reduction measures, including recon- necting streams with their floodplains. • Tracking and Reporting Results: The TMDL included development of the Lake Clarity Cred- iting Program an innovative, comprehensive ac- counting system that measures the amount of key urban stormwater pollutants entering the lake and sets load reduction targets, or "Lake Clarity Cred- its," that city, county and highway agencies must achieve. The program enables greater transparen- cy and accountability for expenditures on water quality improvement projects and is a model for other urban stormwater programs confronting similar issues. Adaptive TMDL Management System procedures enable TMDL program managers to report on accomplishments, better identify and respond to challenges, and make adjustments to ensure that the TMDL is working. Current results show that the TMDL is on track to achieve expected fine sediment load reductions at the first 5-year milestone (20 f 6). What Are EPA's Priorities for Lake Tahoe for the Next 20 Years? EPA will continue to work with our federal, state and local partners, and the Washoe Tribe to support the TMDL planning and implementation needed to restore deep water clarity, improve nearshore water quality, and protect Lake Tahoe as a drinking water source. Our priority will be to support projects with multiple and sustainable benefits, especially to improve watershed resilience to the effects of climate change. We will also continue to invest in applying and improving scientific tools to predict and measure project benefits. What Can YOU Do to Protect Lake Tahoe? Visit the Tahoe Regional Planning Agency website and find out "10 WAYS TO SAVE LAKE TAHOE" for both homeowners and visitors. Choose native plants: to reduce water, fertilizer and pesticides. Use phosphorus-free fertilizer: to reduce algae growth. Adopt a storm drain: to keep sediment and other pollutants out. ^ Bike, walk, or catch the bus:j to reduce air pollution. 1 Don't litter, pick up trash: to keep trash out. Replace old woodstoves: to reduce air pollution. Install and maintain Best Management Practices: to keep sediment and other pollutants from flowing off your property. Volunteer: to help clean up and get involved. Clean, drain, & dry: to prevent invasive aquatic species. Become a Tahoe Keeper: learn to spot invasive species on your paddle crafts. Pick up after your pet: to keep bacteria and nutrients out. Get defensive!: defensible space reduces wildfire risk. Support restoration efforts: to improve Lake Tahoe's ecosystem and water quality. For more information: Jacques Landy, U.S. EPA Lake Tahoe Basin Coordinator Tel: (775) 589-5248 Email: landy.jacques@epa.gov Learn more about the activities of EPA and partner agencies at EPA's Lake Tahoe website at www.epa.gov/lake-tahoe ------- |