21st Tahoe Summit is Tuesday | RecordCourier.com

21st Tahoe Summit is Tuesday

Staff Reports

"The Dome" by Dylan Silver, whose work explores the clarity of Lake Tahoe.

Local governments at Lake Tahoe are meeting targets to reduce urban stormwater pollution and restore the lake's famous water clarity, according to a report released by the Nevada Division of Environmental Protection and the California Regional Water Board, Lahontan Region.

On Tuesday scientists and politicians gather for the 21st Lake Tahoe Summit hosted by Sen. Dianne Feinstein, D-Calif., 10 a.m. to noon at Valhalla Tahoe in South Lake Tahoe.

The Lake Tahoe Total Maximum Daily Load Program 2017 Performance Report will be among the topics of discussion at the summit, which was first held in 1997 and featured President Bill Clinton and Vice President Al Gore among the attendees.

"Local governments and highway departments are doing tremendous work at Lake Tahoe to reduce stormwater pollution that harms lake clarity," said Lahontan Water Board Executive Officer Patty Kouyoumdjian, "Because of this work, more than 268,500 pounds of fine sediment particles – which equates to about 70 dump truck loads of fine sediment – will no longer be washing into the lake each year. The accomplishment of this first round of reductions is a major milestone for Tahoe." 

The report finds that local governments and highway departments at Lake Tahoe collectively exceeded the first round of five-year pollutant reduction targets to reduce fine sediment loads by 10 percent. 

The Lake Tahoe TMDL program is focusing on reducing the amount of fine sediment flowing into the lake in stormwater, as research indicates this pollutant has a greater impact on clarity than other causes.

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One source of the fine sediment is the sand and other wintertime traction abrasives that are routinely applied to roads to prevent cars from slipping. The abrasives are eventually picked up and carried by stormwater into the lake, which reduces clarity.

As shown in the report, local governments have utilized the best available road operations technologies to reduce the amount of abrasives applied to roads, while maintaining driver safety.

They also improved recovery of these materials by installing stormwater treatment infrastructure that captures and cleans dirty runoff. Collectively, TMDL implementation actions have reduced the amount of fine sediment in the lake, or sediment loads, by 12 percent from 2004 baseline levels. They have also reduced the amount of phosphorus and nitrogen in the lake by 8.5 percent and 6 percent respectively.

Launched in 2011, the TMDL Program is a science-based plan to restore Lake Tahoe's water clarity back to its historic level of 97.4 feet by 2076. The program requires local governments and highway departments at Lake Tahoe to meet regular targets to reduce the amount of clarity-harming pollutants that wash into the lake.

Fine sediment particles that wash into the lake scatter light, reducing lake clarity. The nutrients phosphorus and nitrogen deposited into the lake can trigger algae growth that also harms lake clarity. 

The 2017 TMDL Program Performance Report is organized according to urban and non-urban pollution categories. Stormwater from roads and urban areas is the largest single source of fine sediment particles. These areas represent the greatest opportunity to control fine sediment pollution. Restoring Lake Tahoe's clarity hinges on meeting urban stormwater pollution reduction goals and sustaining pollutant control effectiveness through regular and continued operations and maintenance. 

Forested uplands in the Tahoe Basin are estimated to contribute more than a quarter of the total phosphorus loading into Lake Tahoe, while atmospheric deposition from vehicle emissions comprises the majority of nitrogen loading into the lake. The U.S. Forest Service, California State Parks,  Nevada State Parks, and other agencies have completed important restoration and land management work needed to achieve TMDL targets.

The report released today assesses the work done by local, state and federal land and natural resource management agencies to implement water quality improvements. It shows that their progress will be sufficient to achieve pollution reduction goals for non-urban sources. The Lahontan Water Board and NDEP celebrate this initial success, and look forward to continued progress at restoring Lake Tahoe's clarity.

"Reducing pollutant loads from non-urban sources remains an important part of restoring Lake Tahoe's historic clarity. Our review of the accomplishments over the past several years indicates that implementation efforts remain on track with TMDL established goals," said Director of the Nevada Department of Conservation and Natural Resources, Bradley Crowell.

Lake Tahoe's water clarity reached an all-time low of 64 feet in 1997. Water quality improvements implemented through the Tahoe Regional Planning Agency's Environmental Improvement Program have enabled the TMDL Program to exceed its first clarity restoration target of 71 feet of clarity by 2016. Five year average clarity in 2016 increased to 73 feet, a five foot improvement since the TMDL was signed. The next interim target is a five year average of 78 feet of clarity by 2026.

"Restoring Lake Tahoe's famous water clarity requires concerted action around the Tahoe Basin. Meeting this first round of pollution reduction targets and the first clarity restoration target through the TMDL shows that the Tahoe Partnership is strong and working," said Joanne S. Marchetta, Tahoe Regional Planning Agency Executive Director. "Achieving lake clarity and many other watershed goals will only be possible through continued partnership and collaboration."

IF you go

What: 21st Lake Tahoe Summit

Where: Valhalla Tahoe in South Lake Tahoe

When: 10 a.m. – noon Tuesday

Info: https://tahoefund.secure.force.com/events/CnP_PaaS_EVT__ExternalRegistrationPage?event_id=a0s1600000ElM8PAAV

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