By Julie Regan and Jason Vasques
The clearness of Lake Tahoe’s deep, blue waters tells a story. The lake’s incredible clarity, which today runs about 60 to 70 feet deep, is among Lake Tahoe’s most famous features, and despite having been on the ropes more than once in the past 100 years, that clarity endures.
Tahoe Conservancy Executive Director Jason Vasques
TRPA Executive Director Julie Regan
The most recent report on Lake Tahoe’s clarity from the UC Davis Tahoe Environmental Research Center shows that the visibility of the lake’s water averaged 62 feet last year. By any standard, being able to see a 10-inch white disk descend six stories into a body of water is amazing. But as the report attests, the depths being measured could be better, could be worse, and must be better understood.
When scientists began dipping that disk in the lake nearly 60 years ago, lake clarity averaged nearly 100 feet. Annual monitoring of the lake’s health has created one of the longest records of freshwater research in the world. That record tells a story of missteps, gained insights, innovation, and successful conservation. As numerous agencies and private property owners work to regain that lost clarity in a time when climate change, wildfires, and aquatic invasive species threaten everything we love about the Tahoe Region, it is critical that we strengthen our resolve to preserve Lake Tahoe for all to enjoy.
Its clarity is more fragile than you might think. For millions of years, the forests, meadows, and wetlands of the Lake Tahoe Basin slowly filtered snowmelt and runoff from the surrounding mountains. The delicate system remained intact for another 10,000 years through the traditional ecological practices of the lake’s original and current stewards, the Wašišiw, or Washoe people.
In the 1800s, European Americans deforested the basin to support mining operations on the great Comstock lode, causing a short-lived but extreme loss of lake clarity. Years later, an uncontrolled building boom in the mid-20th century took the lake’s natural systems to the brink of destruction. As sewers and septic systems drained into the lake, plans were drawn up for freeways and a city the size of San Francisco to fill the watershed.
By the 1960s, scientists provided grave insights that the consequences of overdevelopment threatened to turn the lake gray or green with algae. The states took action to mandate sewage be treated and transported out of the basin. Then, in 1969, California, Nevada, and the federal government adopted a bi-state compact to create the Tahoe Regional Planning Agency—the first interstate compact of its kind in the U.S. The agency enacted regional conservation programs and science-based policies that capped future development. Land acquisitions through federal and state agencies including the California Tahoe Conservancy further reduced development and made room for wetland restoration projects. Although development slowed, the damage was done. Lake Tahoe continued to lose clarity for nearly 30 years.
A turning point came in 1997. Federal, tribal, state, and local partners renewed their efforts and launched the Lake Tahoe Environmental Improvement Program. Under the Environmental Improvement Program, public and private partners embarked on projects to protect natural resources and address the root causes of clarity loss. Today, despite new pressures from climate change impacts, clarity is holding steady, and may be improving in winter months, while summer clarity is declining.
Despite the mixed trajectory of lake clarity today, the Tahoe Basin is meeting or exceeding targets for reducing pollutants. Under the EIP, public and private partners have retrofitted roadways and developed properties with erosion control and stormwater infiltration infrastructure. The California Tahoe Conservancy and other Environmental Improvement Program partners have rehabilitated more than 1,400 acres of damaged wetlands, improving biodiversity and regaining some of Tahoe’s natural filters. These projects are keeping more than 500,000 pounds of pollutants out of the lake every year from urban areas alone. Scientists tell us these reductions are improving water quality, and that we need to stay the course while supporting additional research.
Tahoe has its challenges and complexities: Two states, six local governments, vast National Forests, and more than 40,000 private properties all intersect in the watershed. Although the region is just one-third the size of Yosemite National Park, Lake Tahoe can see three times the visitation Yosemite sees. Emerging factors like extreme weather, warming temperatures, aquatic invasive species, and wildfire smoke are adding further challenges to the lake’s health.
Although it’s clear more research is needed to finish the job of restoring clarity, progress can be seen and experienced all around. Today, a full 90 percent of the basin is public land. It’s easier for you to dip your toes in the lake, or wade in one of the creeks that flow into it, because of decades of work to increase public ownership of lakefront and river corridor properties. It is critical that these public lands stay protected and accessible to all.
Peregrine falcons and sandhill cranes are returning to basin after being absent for decades. You now have more ways to get around the Lake Tahoe Basin than ever by walking, biking, and rolling instead of by car. These are what government documents often call the “multiple benefits” of projects. For everyone else, it’s a bit more of all the reasons we love Tahoe.
Continuing this progress and restoring lake clarity will require not only the stewardship and commitment of everyone who loves Lake Tahoe. We must ensure agencies and scientists can continue to work together so that science drives action, as it has for decades, to protect the extraordinary natural resources of Tahoe for future generations to enjoy.
Authors:
Julie Regan is Executive Director of the Tahoe Regional Planning Agency, where she has held executive positions since 2003. Julie is the past Co-Chair of the nationally-focused Network for Landscape Conservation and has contributed writings on destination stewardship to the global conversation on overtourism. She is currently a doctoral candidate in environmental science at the University of Nevada, Reno.
Jason Vasques is Executive Director of the California Tahoe Conservancy with a mission to lead California’s efforts to restore and enhance the extraordinary natural and recreational resources of the Lake Tahoe Basin.