Ocean water desalinated at a controversial plant in Carlsbad soon could be stabilizing supplies for south Orange County residents served by Moulton Niguel Water District, who now depend on fluctuating allotments from the Colorado River and Northern California to keep their taps flowing.
In exchange, western San Diego County residents could see some relief from their soaring water bills if south O.C. residents start to absorb some of the hefty costs associated with turning seawater into drinking water. But it’s not yet clear how much, or if, a deal to use Carlsbad water might drive up water bills for Moulton Niguel customers.
While it may seem shortsighted not to tap the ocean to help address water shortages in Southern California, desalination remains a controversial piece of the region’s water supply puzzle. Desalinated water currently costs more than twice as much as imported water, and the process of turning ocean water into tap water can harm marine life and water quality. That’s why it can take decades and hundreds of millions of dollars to get a new desalination plant built, with critics who fought the $1 billion Carlsbad plant still describing it as a “boondoggle.”
But Gov. Gavin Newsom and other state leaders insist desalination needs to be part of California’s water portfolio going forward to help us weather climate change. And if Moulton Niguel’s potentially first-of-its-kind swap for desalinated water rights goes through, leaders of other water agencies hope it will serve as a model for other communities looking for creative ways to make water supplies and prices more reliable before the next drought.
“I think that what we’re doing really should be, and will be, the future of water management in Southern California,” said Dan Denham, general manager of the San Diego County Water Authority.
No costs or volumes are on the table yet. But Moulton Niguel Water District’s board voted on Thursday, Feb. 29, to give staff up to three years to negotiate with the San Diego agency over a potential transfer of rights to some water generated each day at the Claude “Bud” Lewis Carlsbad Desalination Plant.
San Diego County Water Authority, a wholesaler that provides supplies for the western third of the county, partnered with the private Poseidon Water to open the Carlsbad plant in 2015. That now is the largest desalination plant in the Western Hemisphere, using reverse osmosis to pump out up to 50 million gallons of purified seawater each day, enough to meet 10% of the San Diego region’s demands.
And the plant is about to get bigger. Regulators recently approved plans to add a pumping station at the existing site, boosting production to as much as 60 million gallons a day. But the expansion will happen as part of a broader, $247 million overhaul to help the Carlsbad plant meet new environmental regulations. Other changes will include a new intake structure to reduce the number of fish that get sucked into the plant, and reducing the concentration of briney wastewater discharged back into the sea.
Through 2045, San Diego County Water Authority is obligated to buy roughly 43 million gallons of water from the plant each day. That means there’s already up to 7 million gallons a day in excess capacity that Moulton Niguel could potentially tap into, with another 6 million gallons on the table once upgrades are complete.
But some of the 23 water agencies that get supplies through the San Diego County authority want to see desalinated water make up a smaller share of their water source going forward. The city of San Diego, for example, is developing its own pricey water recycling program.
The main complaint is that the price of desal water just keeps going up, with Poseidon water now selling for $3,300 per acre foot while imported water is around $1,500 an acre foot. San Diego area water agencies have had to keep making residents pay more for water to keep up with those spikes and to fund their own projects, with the city of San Diego recently approving a 20% hit to residents’ water bills over the next two years.
That’s where outside agencies like Moulton Niguel Water District, which now touts some of the lowest water prices in Orange County, could come in. If they buy some of San Diego’s desalinated water, it could help stabilize prices for customers there. And since desalinated water still would only make up a small share of the supply for outside agencies, Denham argues the higher price would be diluted for those customers.
“What I would say is it’s not so much about the cost,” he said. “It’s about the drought-proof nature of the supply.. … You’re paying a premium to have water when others don’t.”
Joone Kim Lopez, general manager of Moulton Niguel Water District, noted that at the peak of the last drought, the summer of 2022, imported water was so restricted that residents in parts of Los Angeles County could only water their yards one day a week.
When conditions get that serious, she said, the price of high-tier imported water can soar from today’s price of $1,500 an acre foot up to as much as $8,000 an acre foot. So if her agency could instead turn south to San Diego in those times and buy desalinated water, it could help them avoid inflated pricing or having to implement the most severe water restrictions for residents.
“We do live in a desert environment,” Laura Rocha, water resources manager for Moulton Niguel Water District, said during Thursday night’s meeting. “It’s not a matter of if we will have another drought but when we will have another drought.”
The cost of imported water keeps going up, too. Metropolitan Water District of Southern California, which coordinates supplies for the region, is eyeing a 13% rate increase next year after people have gotten so good at conserving water that the district’s revenues have plummeted. Still, unlike forecasts from a decade ago, Denham said he’s no longer sure imported water will ever cost as much as desalinated water.
Moulton Niguel is pursuing a water recycling project of its own. But Lopez said all options need to be on the table. So she hopes staff from her agency can work with the San Diego agency over the next few years to negotiate an agreement where they won’t be required to buy a minimum amount of desalinated water each year, but could instead tap the resource only when needed.
“We want to make sure it’s a smart investment for what we need.”
If a deal is approved by the boards from both agencies, O.C. residents still wouldn’t actually be drinking desalinated water.
Instead, the agencies are now negotiating what may be a first-of-its-kind deal in the state to transfer desalinated water rights, or what’s called “paper water” vs. “wet water.” So instead of transporting purified seawater 44 miles between the Carlsbad plant and Moulton Niguel’s district, the two agencies would swap rights on paper. The desalinated water Moulton Niguel paid for would still get mixed into San Diego’s system, while imported water that would have gone to San Diego would instead go to Moulton Niguel’s customers.
Such paper water transfers are common across the state. Water agencies regularly swap rights when, say, a farmer wants to sell rights while they let a field go idle. But limited desalination projects that exist across the state have so far typically been used to provide “wet water” for nearby communities.
If paper transfers are built into desalinated project plans, it could help spread costs between multiple agencies and get that water to communities in need, which often are miles from the coast.
One of many objections to a desalination plant that Poseidon spent 21 years and an estimated $100 million trying to develop in Huntington Beach was that part of Orange County already had access to reliable, affordable water supplies from a vast underground aquifer. The California Coastal Commission shot that project down two years ago.
With lessons from that failed project in mind, South Coast Water District in Laguna Beach has planned from the start to have partnership agreements locked down before agreeing to build the planned Doheny Ocean Desalination Project in Dana Point.
That 5-million-gallons-a-day plant got the greenlight from regulators in 2022. In December, Eastern Municipal Water District, in Riverside County, approved a plan to buy paper water rights from the Doheny plant. And Rick Shintaku, general manager of South Coast Water District, said they hope to see three more agencies — Laguna Beach County Water District, the city of San Clemente and Elsinore Valley Water District — consider joining the project over the next two months.
When asked why Moulton Niguel isn’t on that list, Lopez said that project still has a long way to go. She’d also prefer to not be locked into buying pricey desalinated water every year. But if they can’t reach an agreement with the San Diego authority, Lopez said they might reconsider the Dana Point project.
Source: Orange County Register
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