California's Dying Lakes

A combination of warmer climate and water mismanagement has led to the draining of Eagle Lake near Susanville.

While changes could still be made to preserve what’s left, the Bureau of Land Management says getting the lake levels to where they were a century ago would take decades of rain without evaporation — and that’s a scenario that just won’t play out.

Evaporation and winds drop lake levels at Eagle Lake several feet every year. 

“You get 3-5 feet of loss every year so you have to balance that with recharge, and if you don't, then the lake just gets smaller and smaller,” said Stan Bales with the Bureau of Land Management.

Recharging the lake with water is difficult. Eagle Lake sits on the leeward side of the lower Cascade Mountain Range. It’s what’s considered the rain shadow side of a mountain where precipitation hits the area, but it’s not nearly as much as the windward side. You might consider it the leftover rain from a storm. Filling the lake becomes harder due to the smaller rain and snow totals.

“Fredonyer Peak up there is almost 8,000 (feet) and it holds snow nicely, but it's a short run," said Bales.

Eagle Lake is a closed lake basin. There is only one surface source for runoff and it comes from Pine Creek.

Adding to the lake’s dropping levels was the Bly Tunnel. In the 1920s, Leon Bly headed the tunnel project in hopes to bring water from Eagle Lake to the neighboring Honey Lake Valley for agriculture needs.

“The intent was to take Eagle Lake water, increase the flow of Willow Creek, then divert it in Honey Lake Valley and then sell the water through a canal system to farmers, ranchers and try and make money doing that,” said Bales.

Little did they know the water was highly alkaline and not suitable for crops.

“They didn't sell enough water to make money to pay off their debts, and so they went out of business. Bankruptcy," said Bales.

Eagle Lake, and surrounding Susanville and Lassen, are made of volcanic rock. The rock puts a lot of alkalinity in the water leaving the pH balance too high for certain crops to absorb nutrients and grow.

“Because that tunnel did drain a lot of water out of Eagle Lake, the lake got much lower and some people who loved Eagle Lake were not happy with that tunnel operation,” said Bales.

Eventually, a concrete plug was installed with a valve. An argument over water rights was filed by land owners and only a small amount of water was released.

“It became a hot topic in the last six to eight years because the lake continued to drop during the drought, and people felt like that plug was allowing the water to drain and lower the lake. Eventually our BLM manager agreed to shut the valve on that plug,” said Bales.

What used to be a booming lake full of campers and fisherman is now limited to the south side of the lake. The Bureau of Land Management says the water quality from the middle to north sides of the lake were hit the hardest. Algae now grows in shallow water on the northside and is spreading across the lake.

Paul Divine with the California Department of Fish and Wildlife says the algae is impacting many of the water activities.

“That’s been really noticeable, especially with anglers, because they complain about the algae being caught on their lines and they have to reel their stuff in and clean it off before they can catch a fish," said Divine.

Much of the shoreline on the northside has receded tremendously. The beauty and uniqueness of Eagle Lake has not gone unnoticed. Conservation strategies are underway to save the Eagle Lake Trout.

“From the 1900s-1960s, maybe there is 11 different species of fish planted into Eagle Lake and none of them have survived to today, so we only have the native fish,” said Divine.

According to the California Department of Fish and Wildlife, Eagle Lake Trout are genetically adapted to the high alkalinity and warmer temperatures of the lake, so much so they have been used in other California lakes to bring recreation to fisherman, but have also been shipped as far off as New Zealand.

Creel surveys are being conducted to help maintain the fish population at Eagle Lake.

“It's the habits of the fish, what they might be eating that day or changes in the weather, phases the moon. There's all kinds of things you can look at and relate to changes in the feeding behavior of the fish,” said Divine.

A fish hatchery at Eagle Lake helps maintain a healthy population. It’s a start to saving Eagle Lake, but now others are looking into how to further save what’s left.

Valerie Aubrey has devoted her life to Eagle Lake. 

“(It’s) been my heart and soul since birth,” said Aubrey.

Aubrey worked as a fishing tour guide for more than 20 years and is a member of the nonprofit Eagle Lake Guardians. Aubrey blogs about the issues plaguing the once vibrant lake.

“With the drought, the water changing and such, we have very warm water. You know, last time I checked it, I had 70.8 (degrees) to 30 feet,” said Aubrey.

Eagle Lake trout are known to survive in 70-degree water and find pockets of cooler water to settle in, explains Divine.

She hopes recreation activities like ATV and bike riding could keep the economy thriving, if fishing and camping don't boost visitors.

The lake is expected to continue dropping until major snow storms or runoffs empty into it.

Clear Lake is the largest freshwater lake that lies wholly in California. It's also the oldest warm water lake in North America, having formed over half a million years ago, but those ancient waters and surrounding shores hide a dangerous element that could suffocate this treasure.

Warming temperatures and a changing climate are giving algae and bacteria the upper hand. The community isn't willing to give up, though.

Long-time resident Debbie Clarke sees the potential in the lake sitting just 100 miles north of Sacramento and San Francisco.

She recalls summer days from her childhood when the lake would go from 1,000 people to 15,000 people starting Memorial Day weekend. Even though the population of permanent residents has grown, Debbie says it still feels like a close-knit community. One neighbor is even working on revitalizing an old boat slip with hopes of making it a place to swim and fish, if he can find a way to keep out a dangerous bacteria growth called cyanobacteria.

Jim Steele, a retired ecologist and Clear Lake resident, says the cyanobacteria form at the north end of the lake where conditions are ideal. Winds carry the bacteria to the south end of the lake where it dies and releases phosphate, a key ingredient to bacteria growth.

The weather pattern, along with Clear Lake’s geographic history, create a perfect breeding environment for harmful bacteria.

The lake was shaped over a period of almost two-million years from faulting, tilting, erosion and even volcanism. Mount Konocti still stands high as a reminder of this ancient activity. Eruptions from the ring of volcanoes deposited high amounts of phosphorus near the lake. During a rainstorm, sediment containing the phosphorus will be carried down the hills and deposited in the lake.

This starts the recipe for cyanobacteria growth. The combination of elevated phosphorus levels and high temperatures reduces the oxygen in the lake, giving cyanobacteria an opportunity to grow and the upper hand over fish and other organisms.

One of the ways to treat this bacteria, at least on the south side of the lake, is to inject it with oxygen or put on a chemical that would keep the phosphate from coming to the surface. The other option is to head to the place where it all begins, the north side of the lake.

Martin Duncan is a Pomo Tribal member and has a long history. Many of his ancestors died in the lake during a massacre called Bloody Island. His great-great-grandma survived by hiding in the tule weeds surrounding the lake.

Over the years, those tules were removed along with precious floodplains that helped keep the lake in a natural balance. Martin is now working to replant those tules and restore the lake’s natural ecosystem alongside the Robinson Ranch Area Environmental Center. The goal is to reduce unhealthy runoff by integrating native practices with western science. 

Luis Santana, the Robinson Ranch Area Environmental Center Water Manager, says applying this practice to Clear Lake is challenging. He says there are shortcomings when it comes to understanding tribal practices. He believes having more collaboration between tribal, county, state and federal policies, plus funding conservation and restoration efforts can help bridge the gap.

Helping in that effort is E.J. Crandell, Supervisor District 3. He says being part of tribal leadership can get him access to parts of government he wouldn't normally have as a supervisor. For example, he was able to go to the office of tribal governments for California with access to Governor Gavin Newsom. E.J. also serves on a national advisory committee for the Environmental Protection Agency, another way to connect government and native communities.

Those connections are helping push forward efforts like the Middle Creek Restoration Project. E.J. says bringing back the marsh land would help create a collection point for all the sediment and nutrient load coming from the hills that eventually runs off into the creeks and into the lake.

The state of California is also involved creating the Blue Ribbon Committee which includes representatives from tribes, Lake County, UC Davis and the Central Valley Regional Water Quality Control Board. This is part of the state’s ongoing investment in the lake, which include a $2 million multi-year scientific research contract with UC Davis, $5 million in voter-approved bonds from Proposition 68, and a recent $15 million bond-funded investment to aid in the Middle Creek Restoration project.

From native practices and putting more voices at the table to western science, there's community buy-in to keep Clear Lake clear.

Lake Tahoe — the largest freshwater alpine lake in North America — is world-famous for its clear blue water, but the lake faces a multitude of threats requiring constant care and vigilance to keep it that way.

“We're more than a bumper sticker," said Laura Patten, the Natural Resource Director at the League to Save Lake Tahoe, better known as Keep Tahoe Blue. "We really rely on the science to figure out what is happening in the lake."

Patten and other scientists studying Lake Tahoe say climate change and recreation pose the biggest threats to the lake in the 21st century. Longer and hotter periods of heat, more extreme fire seasons, and erratic precipitation patterns in the winter all play a part in Tahoe's water quality.

"We need to think about how are we going to plan for that potential climate future of Lake Tahoe," said Patten. "If we're seeing different patterns in precipitation, in smoke and ash and wildfire, how are we seeing these different pressures impact the lake?"

It's important to understand Tahoe’s crystal "blue" water is actually clear. The clear water reflects the blue sky and absorbs red light, making the water appear brilliant hues of blue. The clearer the water — or the better the water’s quality — the bluer the lake.

"When we think about Lake Tahoe's water quality and the threats that are impacting the water quality today, there are a number of them and they're interactive," said Dr. Sudeep Chandra, Director of the University of Nevada’s Global Water Center. 

Chandra is an expert in freshwater lakes, studying numerous lakes from Southeast Asia to the Eastern Sierra. 

"We're adding species to the lake unintentionally and often illegally and those species can reorganize how nutrients are given to algae that grow at the edge of the lake," said Chandra.

Algae most often forms in warm and relatively calm waters. Excess nutrients like nitrogen and phosphorus enter the lake via agricultural or stormwater runoff and can act as fertilizer for algae and bacteria growth.

Importantly, not all algae is toxic. But when toxic algae is present, it can be extremely harmful to the ecosystem. When toxic algae overgrowth — known as a harmful algal bloom or HAB — is detected, caution signs are put up around Tahoe warning of the dangers.

"One thing we're concerned about with shifting climate is that if the nutrients get delivered at the right time and the temperatures are elevated, we might select for more harmful algal blooms," said Chandra.

But could Tahoe turn green? We've seen other lakes in California struggle against and even lose the battle against algae, turning the water green.

When a harmful algal bloom happens, options to fight it are limited. It's better and cheaper to stop HABs before they happen, but it's not just algae posing a threat to Tahoe's water quality.

Invasive aquatic plants are also a problem, and these are most often introduced to the lake via unscrupulous boaters and boarders.

"One thing that we really focus on is the prevention of the spread of aquatic invasive plant species," said Patten. "That's really integral to making sure that we keep Tahoe blue and not green. Aquatic invasive plant species make their way primarily through boats. They can also make their way into Tahoe through something like a paddle board or a kayak so we really encourage everybody to clean, drain and dry. It's really up to everybody to make sure that they're not spreading aquatic invasive plants."

Boat inspections have been mandatory at Lake Tahoe since 2008, and permanent inspection stations are right now being placed on both the California and Nevada sides to help keep invasive species out.

Lake Tahoe is basically a giant granite funnel, so whatever happens in the greater Tahoe region has the potential to impact the lake. The Upper Truckee River carries sediment and other particle pollution into Lake Tahoe, which Patten says is the largest contributor to fine sediment pollution.

"We're really focused on restoring marshes and meadows so that those can act as big filters to make sure that those nutrients that feed things like weeds and feed things like algae are not getting into the lake," said Patten.

These marshes on the outskirts of the lake are essentially big filters, before the freshwater from the rivers meet up with the lake body itself. These marshes filter out the fine sediment before it gets into the lake, and the marshes also absorb excess nutrients, preventing algae growth in the lake itself.

The catch is there has been more building and development in some of the marshes. When we encroach on and change the dynamics of the marshland, the filter is less effective. Even with healthy marshes, some pollution isn't as easy to keep out of the lake.

Wildfire smoke can also deposit sediment into the lake which can decrease water quality and lead to algae growth, however, not all wildfire smoke has the same impact on the lake.

In 2021, the Caldor Fire raced towards South Lake Tahoe. Thick black smoke and ash fell into Lake Tahoe, and scientists were watching. The results were surprising. The smoke had less effect on algae growth than the very fine particles coming from fires hundreds of miles away.

"Not all smoke is created equal when you have fires," said Chandra. "When you have fires — for example the Caldor Fire at the south end of the basin in 2021 – that heavy smoke and ash that's deposited closer to the fire turns out to be less reactive and it doesn't grow as much algae. But the fine thin particles further away from the fire that maybe make the beautiful sunsets that we see, they actually have a lot of nutrients and metals that can stimulate algae growth."

Protecting the lake and keeping it blue really comes down to restoration.

"The more restoration that we can do in Lake Tahoe, the more we can protect it and keep Tahoe blue," said Patten, reciting her organization's mantra.

The federal government is helping to keep Tahoe blue. Since 1997, hundreds of federal projects have restored wetlands, reduced wildfire fuels and helped control invasive species. Congress just reauthorized the Lake Tahoe Restoration Act, extending funding of about $300 million to protect the lake’s water quality.

"Lake Tahoe is something that everybody cares about and that's just so incredible whether you're in DC or Sacramento," said Patten. "We have the tools to be able to respond to those [threats] because of how strong Lake Tahoe is with all of those counties, agencies, the community that lives here all really cares about it. We're really unique in that way."

Still, more can be done.

"We often get this question of like, well, if we continue on the current pace of activity, is the lake just going to change dramatically? I don't think we're quite there yet, but I do think we're on this teeter totter," said Chandra. "We just don't know, but I'm worried as a scientist — a conservation scientist — that unless we make some of these subtle changes that in 10 or 20 years, our kids won't have the ability to change things back. I'm not ready to give up on the lake and I'm not ready to say, 'Oh, it's all a disaster,' because there are little things that we can do that that would protect the lake in big ways into the future."

Throughout the 'California's Dying Lakes' series, we've seen some sobering images of some of California's beautiful blue lakes going green. Eagle Lake, Clear Lake and Lake Tahoe are each unique in the factors that most contribute to the water color and clarity changing, but they are unified on one front — finding a solution.

ABC10 meteorologist Rob Carlmark took a trip to Southern California's largest natural lake, Lake Elsinore. This lake is facing the same scenario, but the leaders of the community surrounding the lake are taking the next step. They put forth real action and are getting results.

If you haven't heard of Lake Elsinore, it’s a place that has what you would want in a smaller town. It has a quaint main street, with trees lining brick blocks of a downtown with mom and pop shops. It has a barber shop with an old barber pole and a popular dive bar, the Wreck.

Lake Elsinore’s Historical Society says it's kept people coming and staying since the 1800s. Celebrities like Steve McQueen and the original Dracula, Bela Lugosi, visited often decades ago for work and leisure, but the star of the town is the lake.

It's the largest natural freshwater lake in Southern California. It is fairly shallow but six miles long and the surface area is nearly 3,000 acres.

"The lake is the jewel of the city and it is the centerpiece. We attract visitors from all over the world," said mayor Steve Manos.

When the lake turned green with toxic cyanobacteria algae in 2022, the town was heavily impacted. They've had numerous periods of the water turning green, but the outbreak prompted a six-month closure.

Residents demanded Lake Elsinore’s mayor and city council address the issue.

"It tends to have this particular problem with cyanobacteria where the algae blooms come about each summer. In past years it's caused massive fish kills which then in turn cause other problems and feeds the ongoing annual problem of the large algae blooms," said Manos about the lake.

All lakes have different factors aiding algae growth. At Lake Elsinore, treated wastewater adds elements like phosphorus that helps algae grow. The water quality can also be affected by decades of hotter years with longer periods of drought. A prolonged warmer, shallow water table adds to more devastating blooms. The lake went through one of its most dangerous outbreaks of toxic green algae in March 2023.

Before the outbreak, the city spent millions upgrading businesses and boat launches at their Launch Pointe facility. These campgrounds and restaurants were not used to their full potential when the lake closed.

The mayor says the residents spoke up.

"They want to see something done and no matter how difficult that is, they'd like to go ahead and see us make the effort," said Manos.

He tasked the city council and others, like community support manager Adam Gufarotti, to come up with a plan to save the lake.

"We are really pushing hard to make changes now. Our residents deserve this, the region deserves a lake that they can swim in year-round and we are going to deliver on that," Gufarotti said during a tour of the lake in August.

He also adds they planned to move quickly, something even residents may not have expected. The city passed a sweeping lake management plan during the lake’s closure and within months, they had the first pieces of a purification puzzle in place.

Among the many things the city of Lake Elsinore has tried to do in the lake to help the water quality is a floating nanobubbler. They say they are getting results.

A barge keeps the nanobubbler in place, which emits very tiny bubbles in a test portion in the lake that are suspended in the water column instead of floating up. This process is designed to disrupt the typical lifecycle of algae growth and improve clarity.

The city installed a test bubbler on the north side of the lake. That year, mother nature also provided ample rain over the winter, and officials saw results within the first year.

During the visit in August, Gufarotti compared satellite images of the outbreak in March 2023 to the much cleaner lake in March 2024.

The color and clarity of the lake changed. In March 2024, people could see 16 feet under the surface of the lake, and good healthy algae was growing at the bottom.

Gufarotti said the locals were sounding off on social media.

"People were posting photos and other ones were like, 'That can't be Lake Elsinore,' and sure enough, more and more people came down, saw it and said, 'Yes, that's Lake Elsinore,' and then we had our 30 year residents come and say, 'I've lived here my whole life ... and I've never seen Lake Elsinore that clear,'" said Gufarotti.

Manos says the nanobubbler plan will expand with plans to spend $8 million on more, larger nano-bubblers.

"Redemption and certainly hope sprung anew. During the spring time, we saw some very clear water and a very good result that I believe changed a lot of opinions as to what was possible," he said.

For Lake Elsinore, this is just the beginning. In future years, it will likely be warmer with more droughts. Keeping phosphorus in check will also be a challenge.

It's a big problem with no silver bullet, but people are fighting for this little lake town.

"We all as humans deserve a place to swim and enjoy. We need that as part of our life. It's part of our mental health. We need a place to stretch our legs and swim," said Gufarotti.

This approach and effort to keep Lake Elsinore from going dramatically green is gaining international attention. A group from South Africa paid a visit to their first "Global Water Summit" in September to discuss their similar green lake issues and to find solutions, too.