By Adam Jensen and Matthew Renda
Tahoe Daily Tribune
SOUTH LAKE TAHOE — While some officials are rallying around a landmark water quality restoration plan designed to aggressively restore Lake Tahoe’s historical clarity, others are leery of its massive price tag and its still-to-be-determined effect on taxpayers and local jurisdictions.
The Lahontan Regional Water Quality Control Board recently unanimously approved incorporating the Lake Tahoe Total Maximum Daily Load into its guiding document at a meeting in South Lake Tahoe.
The restoration plan focuses on the need to dramatically reduce the amount of fine sediment reaching the lake to restore its historical clarity. Fine sediment particles are smaller in diameter than a human hair and are often swept into the lake in stormwater runoff.
Returning Lake Tahoe to 97.4 feet of average clarity is a component of the federal Clean Water Act, which requires states to compile lists of water bodies that do not meet water quality standards and develop plans to correct such problems. The lake was clear to an average depth of 68.1 feet in 2009.
Incorporating the TMDL into the water board’s basin plan will give the agency the ability to regulate fine sediment as a pollutant.
Nitrogen and phosphorus contributing to algae growth were long considered the major cause of clarity decline, but scientists began to understand fine sediment’s influence on clarity starting in 1999, said John Reuter, associate director of the UC Davis Tahoe Environmental Research Center in Incline Village.
He lauded the recent decision.
“The approval of the TMDL means, for the first time ever, agencies around the lake (will have) a specific target regarding how many restoration projects will need to be performed to begin reversing clarity,” Reuter said. “I would say it is one of the most important water quality decisions in decades.”
Tahoe Regional Planning Agency Executive Director Joanne Marchetta also supported the action.
“The Tahoe TMDL is a culmination of 10 years of collaborative work that will provide a science-based framework to prioritize restoration efforts and erosion-control projects,” Marchetta said. “Using science to get the biggest bang for the restoration buck is not only good for Lake Tahoe, but shows that agencies are being responsible with public and private funds.”
Some representatives from local jurisdictions around the lake that may be responsible for implementing costly measures to reduce sediment and nutrient load are awaiting implementation specifics before they celebrate.
“We are currently unsure of what the specific implications of the TMDL passage means for Washoe County and other local jurisdictions,” said John Breternitz, Washoe County commissioner and TRPA governing board member. “We just don’t know if this will require investment on behalf of the counties, whether the (Nevada general improvement districts) will have to supply a proportionate share. There are a lot of questions to be answered.”
Reuter identified the following three different methods of reducing fine sediment, nitrogen and phosphorus loading into the lake:
• More comprehensive street sweeping mechanisms capable of picking up small particles pulverized by cars as well as larger sand grains.
• Erosion-control measures installed on private and public properties throughout the basin with the ability to filter stormwater, ensuring the water that reaches the lake is relatively pure.
• Creek restoration projects, which focus on stabilizing the banks and slowing the flow of the many tributaries surrounding Tahoe, which naturally filter sediment and nutrients on their course to the lake.
Fine sediment, phosphorus and nitrogen loads entering Lake Tahoe must be reduced by 65 percent, 35 percent and 10 percent, respectively, during the next 65 years to achieve 100 feet of clarity, according to the Final Lake Tahoe TMDL Report, released in June.
An interim goal of reaching about 80 feet of clarity is expected to take 15 years and $1.5 billion, but water board staff has acknowledged the estimate is extremely rough.
Large contributions from federal and state government will be needed to reach the pollutant-reduction goals, said Robert Ehrlich, South Lake Tahoe’s stormwater coordinator, in a September letter to the water board.
“While the city and its residents will continue to contribute to pollutant load reduction projects and programs, it is unlikely that local government and residents can pay for the programs and projects needed to meet pollutant load reduction targets without continued major funding support from state and/or federal sources,” Ehrlich said. “If large amounts of federal and state support are not available, load reduction targets are unlikely to be met.”
South Lake Tahoe City Councilman Hal Cole has expressed concerns the TMDL is an unfunded mandate subject to state review.
But Breternitz stopped short of making that assumption.
“It’s too premature to classify it like that,” he said.
Incorporation of the TMDL into the Lahontan water board’s basin plan still requires approval from the state Water Resources Control Board.
The Nevada Department of Environmental Protection as well as the U.S. Environmental Protection Agency also need to sign off on the water quality restoration plan.
Final approval of the plan could come as soon as summer of 2011.