Douglas County exceeded its requirement for the first milestone of the Lake Tahoe Total Maximum Daily Load (TMDL) Clarity Crediting Program.

The Lake Tahoe TMDL is a science-based plan developed to better understand the causes of the loss in lake clarity, determine how much pollution needs to be reduced to reinstate historic clarity, and develop a workable, cost-effective implementation strategy.

Between 1968 and 2000, approximately one-third of Lake Tahoe’s stunning clarity was lost — going from nearly 100 feet to 68 feet. To address the issue, the Lahontan Regional Water Quality Control Board and Nevada Division of Environmental Protection collaborated to develop the Lake Tahoe TMDL.

Through a registration process Douglas County is required to coordinate with the Kingsbury General Improvement District on road operations, the Tahoe Regional Planning Agency on private parcel Best Management Practices compliance, and maintain water quality improvement projects annually to keep credits in place.

The first milestone Douglas County was required to meet was to reduce fine sediment particles (FSP) load by 10 percent by 2016 for a total of 41 credits. One credit is equal to 200 pounds of FSP. Through the registration of road operations on upper Kingsbury, private parcel best management practices, and four water quality improvement projects, Douglas County successfully registered 53 credits to exceed the first milestone requirement of the Lake Tahoe TMDL.

“Ongoing maintenance is the key to success for the Tahoe TMDL,” said Courtney Walker, Douglas County’s stormwater program manager. “The next milestone to be met will occur in 2021, when the county will be required to have reduced its cumulative FSP contribution by 21 percent and obtain a total of 101 credits.”

The culprit of the clarity decline was determined to be fine sediment particles less than 16 microns in size. FSP comes primarily from the urban areas in the basin. Therefore, each of the seven jurisdictions in Lake Tahoe is responsible for reducing their contribution of FSP. The seven jurisdictions are the counties of Douglas, Washoe, Placer and El Dorado, as well as the city of South Lake Tahoe, California Department of Transportation, and the Nevada Department of Transportation.

Each of these jurisdictions is responsible for reducing their FSP contribution by 34 percent by the year 2026, and 71 percent by 2076 to restore clarity to the 98 foot “historic visibility.” FSP is captured in three ways:

Road operations — modifying winter plowing operations by reducing the amount of sand applied to the road when it snows, and strategic street sweeping to collect the material before it can be washed into the lake when the next storm arrives.

Private parcel best management practices to capture stormwater and infiltrate it on site.

Large scale regional water quality improvement projects — infiltration basins, wet basins and stream restoration.

For questions on the status of the program, contact Courtney Walker, Douglas County stormwater program manager at 775-782-6215 or cwalker@douglasnv.us.