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Los Angeles turns to contaminated aquifer for new water

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As drought and climate change ravage California’s once-reliable drinking water supply, Los Angeles officials are turning to a relatively new and nearly untapped resource for the city’s 4 million people: the Superfund site. in their own backyard.

Nearly 70% of the city’s 115 wells in the San Fernando Valley groundwater basin — the largest such basin under the Los Angeles Department of Water and Power — have gone unused. for decades after dangerous contaminants seeped into the aquifer.

Now the city is close to completing a massive $600 million plan to bring this resource back online. Centered on three treatment facilities in the San Fernando Valley, the groundwater remediation project will essentially create giant filters for the city’s toxic plume, allowing Angelenos to regain full access to up to 87,000 acres- feet of water each year, nearly a fifth of what they consume.

Some say it can’t happen soon enough.

“What drought does is it makes groundwater even more important as a source of water for us – that’s really what it’s all about,” said Anselmo Collins, director Senior Deputy General of the DWP. “The ultimate goal is to be able to take this water and put it into the drinking water network.”

The project took years to prepare, but the problem goes back even further.

In the mid-20th century, a post-war boom transformed the San Fernando Valley into a fertile hotbed for commerce and manufacturing, including major players in the aerospace, automotive, and construction industries. defense. But when these companies began storing and disposing of metals, solvents and other wastes in the area, known carcinogens such as trichlorethylene, perchlorethylene, hexavalent chromium and 1,4-dioxane poured into the valley aquifer.

The scale of the problem was only fully discovered after the Safe Drinking Water Act of 1974 imposed increased testing and monitoring standards for drinking water, according to project manager Larry Sievers. site remediation for the Environmental Protection Agency. By then, the basin was so contaminated that it earned the agency the dreaded Superfund designation, indicating a site so polluted that it requires long-term cleanup intervention.

“Superfund sites are kind of the worst of the worst,” Sievers said. “Every once in a while we get a site like the San Fernando Valley that has just huge reach.”

The Los Angeles Department of Water and Power’s Tujunga Spreading Grounds facility, where the agency will treat contaminated groundwater from the San Fernando Valley Basin. Groundwater was contaminated years ago after toxic chemicals seeped into the basin.

(Robert Gauthier/Los Angeles Times)

Indeed, the massive basin sits under several communities, including large swathes of Los Angeles, Burbank, and Glendale. More than a dozen organizations have a stake in its remediation, Sievers said.

But the bulk of the water rights in the basin belong to the DWP, which has spent years looking for responsible parties to appropriate the pollution, to no avail.

“The challenge we have with the San Fernando Basin is that it’s the biggest basin — the one we have the most rights to — but also the one that’s contaminated,” Collins said.

The city has long relied on other supplies to get by, including water imported from the Owens Valley, northern California, and the Colorado River via a network of aging aqueducts. But as drought undermines these sources, Los Angeles is forced to fundamentally overhaul its water infrastructure.

A group of closed aboveground tanks and buildings on land outside with hills above them in the background.

The Los Angeles Department of Water and Power’s Tujunga Spreading Grounds facility, where the agency will treat contaminated groundwater from the San Fernando Valley Basin.

(Robert Gauthier/Los Angeles Times)

Currently, only 10% of the water used by the city is of local origin. The DWP hopes this will increase to 70% by 2035 as filtration equipment and other major projects are completed.

“Not only does that make us more drought resistant if you have water, especially in the underground basin, but also a bit more resistant to earthquakes,” Collins said. “Because it’s not a matter of if, it’s a matter of when we’re going to have an earthquake, and the aqueducts are going through the San Andreas Fault.”

Mark Gold, a Los Angeles water expert and assistant professor at UCLA’s Institute for Environment and Sustainability, said he was pained to think such a precious resource was underutilized for a good part of four decades.

“The only people who got paid were the lawyers and the groundwater study people, but ultimately the public didn’t get their supply,” Gold said. He noted that dwindling state and federal supplies and rising water costs have made it more urgent than ever to get the basin back into the mix.

“To say that we should be able to get a quarter of our water supply from the groundwater of the City of Los Angeles is no exaggeration at all,” he said. “Sustainable local water is where we need to go…and groundwater is an important part of that.”

In fact, restoring the San Fernando Valley groundwater basin is a huge part of Los Angeles’ plan for the future, which includes big investments in water recycling and stormwater capture as well as ‘a persistent push for conservation, all in the name of reducing reliance on imported supplies.

But cleaning up decades-old contaminants from a major municipal water source is a daunting undertaking. The multi-step process will include pumping the water out of the ground and then passing it through a series of filters and treatments, according to Evelyn Cortez-Davis, director of water engineering and technical services at DWP. .

She walked the steps during a recent tour of the Tujunga Spreading Grounds facility in Sun Valley, which will house the largest of the project’s three sites when completed in 2023.

A man in a helmet near a collection of filtration tanks outdoors.

DWP Civil Engineer Jose Rubalcava near a collection of filtration tanks at the Tujunga Spreading Grounds facility.

(Robert Gauthier/Los Angeles Times)

First, the pumped water will be cleaned with hydrogen peroxide, then pushed through filters to remove sediment such as dirt and sand, Cortez-Davis said. Then the water will be bombarded with hundreds of ultraviolet lamps for disinfection. Finally, it will pass through huge tanks of granular activated carbon, which will adsorb any residual hydrogen peroxide and remove other harmful compounds.

Only then will it be ready for the standard treatment that all LA tap water receives, including doses of chlorine, ammonia and other additives. The treated water will meet all federal and state drinking water standards, Cortez-Davis said.

Filtration tanks in a row outside.

Filtration tanks at DWP’s Tujunga Spreading Grounds facility.

(Robert Gauthier/Los Angeles Times)

She noted that due to the way the city is plumbed, the water will not stay in the San Fernando Valley but “will be integrated into the entire distribution system”, benefiting almost all of Los Angeles.

“The city has been focused on conservation for so long that we’re doing it really, really well,” Cortez-Davis said as he walked around the construction site. “The part that I think is sometimes lost on people is how much we rely on groundwater during dry spells, and the fact that so many of our wells have been impacted for so long.”

But part of the reason the site has gone unused for so long is that officials spent years in litigation and worked to find responsible parties who could help pay for cleanup costs.

Some large companies, including Honeywell and Lockheed Martin, have already agreed to take over some of the decades-old chemicals and pledged to fund cleanup efforts or compensate in-kind losses, according to the DWP. Others have yet to be identified, and some may not exist all these years later.

“So it behooves us as stewards of our groundwater basin to make sure that we continue to have access to that groundwater because it is a critical supply,” Cortez said. Davis. Rather than wait for a resolution, “the alternative was for the taxpayers of Los Angeles to proactively do this and reclaim our resource.”

That means Angelenos bear some of the cleanup costs, she said, although the EPA and the cities of Burbank and Glendale also treat water in other parts of the basin.

“It’s tricky, and we all depend on it,” said Richard Wilson, deputy general manager of Burbank Water and Power. “We have to be good stewards of the water that we import, the water that we have in the ground, and that’s a regional problem, especially with the drought.”

In Los Angeles, nearly half of the project’s money so far — about $310 million of $634 million — comes from state grants through Proposition 1, a water bond of 7.5 billion passed by voters in 2014.

Joe Karkoski, deputy director of the financial aid division at the National Water Resources Control Board, which administers the funds, said this was precisely the type of project for which the bond was created.

“As they are able to clean up groundwater contamination, they are bringing more of their municipal wells back online that were meant to be made inactive,” he said. “That means their portfolio starts to change over time – they become less dependent on surface water…and more dependent on local groundwater resources.”

Other projects are also underway, including the dual use of the Tujunga site as an improved land application facility to capture more stormwater when it rains. With some treatment capacity already operational, the city has doubled Tujunga’s capacity to capture stormwater from 8,000 acre-feet per year to 16,000, or about 5 billion gallons, officials said.

UCLA’s Gold said the scope and scale of projects in the San Fernando Valley give him “tremendous hope” for the city’s water future.

“We get reliable, local water supplies,” he said, “and that’s something we need a lot more of here in the state of California.”

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