Pollutant control measures kept over 550,000 pounds of fine sediment out of lake in 2023 despite extended snowmelt period, new California-Nevada report shows

Aug. 14, 2024

Media Contacts:
Nick Cahill, CA State Water Resources Control Board, nick.cahill@waterboards.ca.gov
Jenny Jackson, NV Division of Environmental Protection, jjackson@dcnr.nv.gov

Lake Tahoe, CA/NV – A bi-state effort to reduce pollution and restore Lake Tahoe’s world-famous water clarity kept significant amounts of stormwater and fine-grained sediment out of the lake in 2023, despite challenges from a winter of record snowfall and runoff, according to an annual lake performance report released today.

While a prolonged snowmelt period in spring 2023 swept sediment into the lake and reduced clarity, partners in the Lake Tahoe Total Maximum Daily Load Program (TMDL Program) helped keep the lake’s annual average clarity at around 68 feet, which is in line with what has been observed over the past two decades, the bi-state report shows. This was achieved despite continuous periods of heavy snowfall and cold temperatures in 2023, which hindered street sweeping and stormwater infiltration efforts for long stretches.

The report by the Nevada Division of Environmental Protection (NDEP) and the Lahontan Regional Water Quality Control Board (Lahontan Water Board), which is an agency under the umbrella of the California Environmental Protection Agency, found that 553,000 pounds of fine sediment and more than 4,300 pounds of nitrogen were prevented from reaching the lake in 2023.

“Lake Tahoe is globally renowned for its iconic clear blue waters and unique ecosystem,” said California Secretary for Environmental Protection Yana Garcia. “In the face of challenging winter conditions in the region, we partnered with Nevada to protect the lake from unprecedented runoff. Today, we are proud to celebrate the results of that ongoing partnership.”

Partners worked to limit fine sediment, nitrogen, and phosphorus, which are the pollutants that reduce clarity and harm the lake’s ecological health. Key prevention strategies include controlling stormwater runoff from paved roads, parking lots and construction sites, targeted application and quick recovery of winter traction sand from roadways and restoring riverbeds and creek channels.

“These efforts are crucial for maintaining water clarity and the overall health of the lake,” said Jennifer Carr, NDEP administrator. “We are grateful for the continued efforts of our urban partners, including Nevada and California transportation agencies and numerous county departments.”

Key findings and accomplishments from the 2024 performance report include:

• California Department of Transportation, the city of South Lake Tahoe, El Dorado County, Nevada Department of Transportation and Washoe County exceeded their targeted pollutant load reductions.
• Pollutant controls are estimated to have reduced fine sediment particle loads by 553,325 pounds, nitrogen loads by 4,380 pounds and phosphorus loads by 1,580 pounds.
• Nevada exceeded its statewide clarity credit goal.
• 5,148 miles of streets were swept, 2 miles of forest roads were decommissioned, and nearly a half-mile of pedestrian and bicycle routes were constructed.

“By working together, we persevered in the face of a historic winter and this outcome reflects a steadfast commitment to preserving this environmental jewel for generations to come,” said Ben Letton, Lahontan Water Board acting executive officer.

The TMDL Program was launched in 2011 and seeks to restore clarity to a depth of at least 78 feet by the end of 2031, through the efforts of federal, state and local agencies, as well as private landowners in the basin. This interim goal is referred to as the “Clarity Challenge.” In time, the goal is for people to once again be able to see to depths of 97 feet.

The TMDL Program awards credits to implementation partners by tracking pollution reduction activities like street sweeping and stormwater infiltration. It allows implementers to use customized strategies for holistic pollution reduction rather than having to take a one-size-fits-all approach.

To learn more about ongoing efforts and to view the detailed 2024 performance report, please visit the Lake Clarity Tracker – Program Management page at LT Info | Program Management (laketahoeinfo.org).