The degradation of Clear Lake and the steps Costner and other water managers are taking to deal with it, are a distillation of the turmoil that algae and cyanobacteria are taking across the United States and around the world. Climate change and nutrients flowing from the land are the primary ingredients of a toxic soup that is endangering lakes and rivers, and challenging public health and economies from California to China, from South Africa to France.
Reducing the threat, as Costner has learned, is expensive. State and federal water quality regulators, prodded by deteriorating conditions at Clear Lake and in other areas, are taking notice.
It all starts with cyanobacteria, sometimes called blue-green algae, ancient single-celled organisms that thrive in warm, nutrient-rich waters. Sometimes they produce toxins. For swimmers, the toxins can cause skin rashes and allergic reactions. Depending on which of the dozens of cyanobacteria species is present, consuming the toxins can lead to intestinal infections, liver damage, or nervous system impairments. Dogs have died from drinking toxin-laced water.
Front of mind for drinking water providers and regulators are recent contamination events that shook U.S. cities from coast to coast. Cyanotoxins from a harmful algal bloom in Lake Erie infiltrated Toledo’s drinking water system in 2014, leading city officials to warn more than 400,000 people not to use their tap water for days.
In 2018, residents of Salem, Oregon, found themselves in the same scenario when cyanobacteria proliferated in Detroit Reservoir and wound up in the city’s distribution system.
The conditions prevalent in Lake Erie’s western basin are also present in shallow Clear Lake, where lakebed sediments are fortified with centuries of accumulated phosphorus. A host of other sources around the lake — septic tanks, stormwater drainage, farm runoff, land erosion — add more phosphorus as well as nitrogen to the mix. Though acute cases of cyanotoxin poisoning in humans are rare, the last thing Costner wants is a crisis similar to Toledo or Salem to unfold for his customers. Fortunately his protections against such an event will soon be strengthened. His district broke ground in March on a near-total system overhaul, a $10 million renovation funded in full by a state grant because the district is classified as a severely disadvantaged community.
The project is expansive. A new water intake will extend 1,500 feet into the lake, nearly four times longer than the current pipe, in hopes of accessing water farther away from the blooms that cluster along the shore. The longer intake will ease the strain on the district’s pumps when the lake is low.
Because electric utilities in fire-prone California are now preemptively shutting off power on dry, windy days to reduce the odds that their transmission lines spark a wildfire, the district will be getting a backup generator, too. A power shutoff in Lake County in 2019 lasted four days, and Costner was able to run his aging generators only 14 hours a day before they needed a break.
Also in the grant package: a new pump house, a raw water line to the treatment plant, a charcoal and sand filter that doubles the filter capacity, a clear well where treated water is stored, and an upgraded computer control system.
The entire project is a response to the severe drought year of 2014, when lake levels plunged and the cyanobacteria grew from a nuisance to a threat, a situation that is poised to reemerge in the months ahead. California just experienced its third driest winter on record. Clear Lake is near the lows from 2014. So Costner is bracing for another grueling warm season.
“It’s going to be a really, really bad summer,” Costner said. “Let’s just hope it doesn’t get as hot as it’s been.”
Costner said that in March. As the calendar turns to May, and with Gov. Gavin Newsom having declared drought emergencies in the counties to the south and west of Lake County, a bad algae year on Clear Lake seems all the more likely.