Most summers, health officials advise Southern Californians to avoid a handful of regional lakes because of toxic algae blooms that can sicken people and pets and kill fish and birds.
Such warnings are becoming more common as climate change accelerates, with drought conditions and warmer temperatures regularly fueling bright green blooms in places like Silverwood, Pyramid and Big Bear lakes.
But few places see algae blooms as early and as often and as severe as Lake Elsinore, which is the largest natural, freshwater lake in Southern California. Because Lake Elsinore sits at the end of the San Jacinto watershed, with no outflow for the nutrient-rich water it collects, the city has struggled for decades to fend off toxins from algae blooms that sometimes limit lake activities or close the lake entirely.
Now city officials hope a new, $2 million “nanobubble” project — which uses microscopic bubbles to get more algae-fighting oxygen to the bottom of the lake — might play a key role in improvement plans aimed at keeping Lake Elsinore open. They see the lake as both a recreation spot and a source of income for area businesses that rely on the visitors it brings from all over Southern California.
“The significance of this body of water cannot be understated. It is integral to the economic vitality and the growth of our city,” Mayor Steve Manos said during a lakeside press conference Friday, Dec. 15. He called the city’s investment into improving the lake’s water quality “not just a prudent decision” but “an imperative one.”
Nanobubble systems don’t come cheap. And unless they’re being used to treat, say, small ponds, their effectiveness is localized to areas where they’re deployed. It’s not yet clear how many systems would be needed to clean up a lake as large as Lake Elsinore, which covers nearly 3,000 acres.
But the science shows promise that such technology could be scaled up and deployed nationwide. The Environmental Working Group, an environmental watchdog and lobbying nonprofit, reports that since 2010 at least 85 communities around the country have spent more than $1.1 billion trying to treat and prevent harmful algae blooms.
“We believe the launch of this innovative and comprehensive solution will become a model for others who are grappling with the same water quality challenges in their lakes and other water bodies, not just here in California but across the nation,” said Nick Dyner, chief executive of Hawthorne-based Moleaer, the company that makes the nanobubble systems, during the press conference.
Elsinore’s decades-long battle
Southern California has relatively few public lakes that allow boating and similar activities, and Lake Elsinore has long been a recreation hub for the region. But the lake also has long been prone to algae blooms, events in which simple plants grow out of control — a result of the lake taking in nutrient-rich runoff from nearby fertilized agricultural operations and lawn care.
In 2016, the lake hit its lowest levels since early 1993. That’s when officials detected the first blue-green algae bloom, which is one of the riskiest types.
Toxins in the algae can cause skin irritation and gastrointestinal problems for humans, and in rare cases high-concentrations can be lethal, according to Marisa Van Dyke with the State Water Resources Control Board. The toxins also can be fatal for dogs and livestock that drink the water and bird deaths have been reported in areas with persistent blooms. Also, blooms can leave behind a trail of odors, scum and foam.
Such blooms happen more easily when water is warm and shallow. Even in a wet year, Lake Elsinore is only 40 feet deep. And a recent report from the Centers for Disease Control on fresh water blooms around the country found that with climate change fueling historic droughts and heat waves such blooms appear to be happening more often, and harming more people and pets.
Lake Elsinore officials have tried several solutions over the years to improve water quality with mixed results.
The city and the Elsinore Valley Municipal Water District each spend more than $750,000 per year to add 5 million gallons of recycled water to the lake a day. But city officials say it’s still not enough to offset evaporation.
The city also has studied the lake’s fish population and worked to remove invasive species such as carp.
In 2008, officials installed an aeration and mixing system, which floats in the middle of the lake and moves the water around to try and prevent stagnation. City records say it’s helped, though Moleaer argues that such systems are inefficient at increasing dissolved oxygen levels — especially near the bottom of the lake, where it’s most important.
The city, like other communities, also has relied on chemicals to treat algae blooms when they occur. In October, Lake Elsinore contracted with a company to apply chemicals to get levels under control.
But such solutions are temporary, and environmental groups have raised concerns about the possible negative effects the chemicals might have on other plants and wildlife.
With all of those concerns in mind, the city of Lake Elsinore recently approved a comprehensive lake management plan. And the nanobubble project is a key part of that plan.
Nanobubbles show promise, with caveats
Tiny gas bubbles, known as nanobubbles, are 2,500 times smaller than a grain of salt. They exist naturally in waterfalls and fog, carrying oxygen and other gases.
While ordinary bubbles in a body of water rise and burst at the surface, nanobubbles are so small that they implode under the pressure of the water. So when they’re injected and released deep into a lake, they’ll release oxygen there, where it can help break up compacted sediment layers and speed the natural decomposition of settled organic matter that otherwise can fuel algae blossoms.
“Nanobubble technology is unlike any other surface water treatment previously used in Lake Elsinore because it addresses the root cause of the lake’s problems,” Dyner said.
“In simplest terms, nanobubble treatment is helping the lake restore itself.”
Fighting algae blooms also isn’t the only use for such systems. Nanobubble technology can help farmers get healthier plants by delivering oxygen-saturated irrigation water; it can speed wastewater treatment processes and it can help bodies of water recover from disasters.
In late 2021, after a fire led to a chemical spill in the Dominguez Channel in Carson, the Los Angeles County Department of Public Works tapped Moleaer to install 14 of its devices at the site. Chemicals from the fire had triggered production of tons of hydrogen sulfide, which caused such a putrid rotten egg smell that residents got sick, and Moleaer’s systems eventually were credited with helping to reverse those conditions.
For the Lake Elsinore project, Moleaer will install two custom-built nanobubble generators in a shipping container on a floating barge. Temporary pipes running down to the lake floor will release enough nanobubbles to treat 2,400 gallons of water per minute, supersaturating it with oxygen to help dissolve harmful algae.
This will be the largest nanobubble system ever deployed from a floating barge, and Elsinore will be the largest lake Moleaer has ever treated. That’s why an engineering firm contracted by the city expressed some doubts about the potential effectiveness of such a system.
“It will be important to have independent review of the water quality data gathered from the lake during operation of the Moleaer units to determine their effectiveness,” that report states.
The $2 million project, already underway about 50 feet offshore from Elm Grove Beach, is in the pilot stage. If the city is pleased with results, more systems could be installed at other spots in the lake.
How many? And how much would it cost? That’s not yet clear. Moleaer officials are still gathering information from multiple water quality sensors to determine how many systems would need to be deployed to treat the entire lake.
Other plans to help Lake Elsinore
Along with the nanobubble pilot project and its potential expansion, the city’s plan to improve water quality in Lake Elsinore includes several more steps.
First is to replace the aeration system, which was installed in 2008 and is reaching the end of its useful life.
Second is to work on a wetland restoration project to revive and recreate the natural habitat around the lake. That should help filter runoff and other incoming water, including from nearby Canyon Lake via the San Jacinto River.
Lake Elsinore also recently secured $1.5 million in grant funds for a 2-year pilot project to install an algae harvester that will filter lake water and separate out the algae. That project is supposed to be installed on the north end of the lake, but is still in the planning stage.