California's oldest lake is in crisis

Leaders warn Clear Lake is facing ecological collapse, demanding urgent action. (City of Clear Lake)

Clear Lake is the heart of Lake County, a popular spot for bass fishing and water sports about 2.5 hours north of San Francisco.

It is also, according to a recent letter sent to the California Legislature, "choking on past pollution and toxic blooms" and "exceedingly malodorous." 

That description comes courtesy of a coalition of stakeholders in Lake County who are requesting upward of $15 million in state funds to rehabilitate Clear Lake. In the warmer months, the lake turns dangerous when toxic algal blooms and cyanobacteria surge. Tests have found cyanotoxins in 56% of homes that draw water from the lake, posing health risks ranging from rashes to liver damage.

Brad Rasmussen, Lake County's District 4 supervisor and a member of the Blue Ribbon Committee, told SFGATE the odor of the algae blooms "can be pretty overwhelming in certain parts of the county along the lake." He described the odor as "very strong" and having its own smell. "I wouldn't really know how to describe it compared to anything else. It's just an offensive smell."

Assembly Bill 707, passed in 2017, established the Blue Ribbon Committee for the Rehabilitation of Clear Lake to spearhead efforts to restore Clear Lake, aiming to revitalize its environment, enhance recreation and stimulate local economic growth.

Toxic algae overtakes Clear Lake in warmer months, posing health risks. (Clear Lake Water Quality)

Rasmussen said the economy of the county he serves depends on "having a lake that people want to use and come to." He is concerned that "if the lake is not in, say, a condition that people can or want to use it, then we're going to have less tourists here, less people traveling here, and that, you know, goes towards the decline in our our tax revenues."

In a joint letter to California legislators dated June 17, members of the Blue Ribbon Committee - including tribal leaders, a Farm Bureau representative and a Lake County supervisor - sent a blunt message about the ancient lake. "We are no longer dealing with a future threat. The damage is already here, and it is affecting drinking water, public safety, and the broader health of our communities." 

Lake County is among the poorest counties in California, as was noted in the original text of AB 707; the June 17 letter says the lake's condition may "disproportionately impact families who may not have the resources to seek alternative" water sources.

That damage extends to wildlife, too. The collapse of Clear Lake has pushed the Clear Lake hitch, a native fish species - also called the Chi "by native peoples since time immemorial," the letter notes - to the brink of extinction. The fish once "swam in large numbers through the lake and its tributaries during its annual migration, sustaining both the ecosystem and Indigenous lifeways," the letter says. "Today, its population has plummeted."

Satellite captures extensive algal bloom on Clear Lake, a sign of ongoing water quality issues. (NASA)

To turn the tide, the Blue Ribbon Committee is asking legislators to pony up for $15.4 million to fund what the letter describes as "12 shovel-ready projects designed to restore Clear Lake's health." Among them: a project to reduce nutrient pollution in the lakebed, one to add oxygen to deeper waters to support aquatic life, and another to install early warning systems to catch toxic algal blooms before they become health hazards.

As the Blue Ribbon Committee puts it, "what happens to Clear Lake doesn't stay in Lake County." The lake's decline isn't just a local issue; its vast footprint connects to water systems that feed farms, ecosystems and communities beyond the county line, including Yolo County and the Sacramento–San Joaquin Delta. Continued degradation, they warn, could trigger a "domino effect that would be felt across Northern California."

The committee insists there's still hope: "Clear Lake can be restored. It can once again be a thriving hub for recreation, biodiversity, and culture. But every season we wait, the path forward becomes steeper."

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