Can the Ocean Save the Colorado River? San Diego Thinks so.

Facing rising costs and rates, the leaders of San Diego’s water lifelines are looking to sell some of its most expensive supply: de-salted ocean water from a massive plant in Carlsbad. But, at the same time, they’re also trying to make more of it.  

Dan Denham, the San Diego County Water Authority’s new general manager, says he wants to expand seawater desalination not because he thinks San Diego needs more water, but because he thinks they can sell it and recoup at least a little of the massive investment local rate payers have made on the plant. It’s Denham’s latest move to try and position San Diego to be a water dealer across the drought-stricken West.

“We’re looking to expand the plant as an opportunity for users, whether that’s in southern California or the lower Colorado River basin,” Denham said.  

Last May, the Water Authority’s government relations team connected with Democrat Rep. Mike Levin’s staffers about securing money from the Inflation Reduction Act funding ($4.6 billion of which the Biden Administration dedicated toward resolving drought on the Colorado River) to ramp up production at the plant, according to emails obtained by Voice of San Diego.  

“Let us know if we can weigh in in support of using IRA funding for plant expansion,” wrote Oliver Edelson, a former legislative staffer for Levin, on May 22.  

When it opened in 2015, the desalination plant in Carlsbad was the world’s largest. It pumps 100 million gallons of seawater through filters each day to produce 10 percent of the region’s water supply. But it’s also San Diego’s most expensive source in part because the desalting process is extremely energy intensive. One acre foot of water (enough for two California households’ indoor and outdoor use per year) costs $3,200. Treated Colorado River water, San Diego’s main source, costs about half that.  

In November, the Water Authority submitted proposals to the U.S. Bureau of Reclamation, asking for $66 million to expand desal water production by 6,000-acre feet, bringing the plant’s total capacity to 60 million gallons of water per day.  

But even if the Water Authority gets the money, expanding that plant won’t be an easy sell. 

Environmental groups and law firms that represent them, like Coast Law Group, would probably fight the plant’s expansion. 

“It seems like a ridiculous move,” said Livia Borak Beaudin, an attorney at that firm. “There are so many (water districts) trying to use stormwater, recycle sewage into drinking water. It doesn’t make sense to use the most environmentally damaging and energy-intensive supply source.” 

 The Coast Law Group, among others, spent years battling against the Poseidon plant’s construction in the courts.  

“We sued (almost) every agency that had a hand in approving that project,” Borak Beaudin said. “We made it such a painful process that it slowed down all the other desal plants planned statewide.” 

Three other large desalination projects floated around the same time as the Carlsbad plant – one in Mexico, Orange County and Camp Pendleton — never materialized. More recently, the California Coastal Commission dashed Poseidon’s hopes of building another large desal plant in Huntington Beach. 

While the ability to constantly sip from the ocean seems like an obvious plus, environmentalists pushed back on its steep costs compared to alternatives like recycling wastewater or stormwater. And, environmentalists don’t like the plant’s 72-inch pipe that pumps in ocean water, and occasionally marine life, from an adjacent lagoon. 

Channelside Water Resources is working on a new intake structure and screens that are supposed to help reduce the number of fish that get sucked into the plant, according to a 2019 press release from the California State Water Resources Control Board. The company is pursuing “the best available technology” to minimize marine life impacts, wrote Michelle Peters, director of operations Channelside Water Resources.  

Denham said the proposed 6,000-acre foot expansion is already allowed under its permits and wouldn’t grow the plant’s physical footprint.   

He also stressed that growing desal is a potential solution for southern California, perhaps the whole lower river basin, to reduce demand on the drought-strained Colorado River. The thought is, San Diego would drink more from the ocean and less from the river leaving those supplies in key reservoirs for others that don’t have other sources to choose from. 

“In concept, this is a … proposal that, in its essence, protects Lake Mead,” Denham said.  

Lake Mead, the huge reservoir behind Hoover Dam on the Colorado River, is like the EKG for the Colorado River, which makes life possible for 40 million people in seven states and northern Mexico and powers a multi-billion-dollar agricultural industry. If water levels at Lake Mead reach certain low points, like in 2022, the federal government begins rationing river water to its users.  

“In this time of uncertainty caused by climate change, seawater desalination represents a drought-proof supply that could provide a level of certainty for the system,” reads an August letter from Denham to the U.S. Bureau of Reclamation as part of $66 million funding request.  

The Water Authority doesn’t have the authority to independently make direct water trades on the Colorado River. But the agency could accept investments from, say, Arizona which is in dire need of new water supplies. And in exchange, San Diego could use more of its desal water and leave some of its contracted Colorado River water in Lake Mead for Arizona.  

The Water Authority has already signaled there’s interest in their desal plant. Its leaders announced they’re formally exploring selling off some of that supply to a small water district in Orange County. It’s a big change for the San Diego supplier, which has traditionally been very protective of its water resources and quiet about dropping water demand in San Diego. 

Denham is upfront about the fact that San Diegans are buying much less water on average, than the Water Authority anticipated, especially in rainy years like this one. Water sales through December 2023 were 24 percent lower than the first six months of the prior fiscal year, according to the Water Authority. For an agency that makes most of its money selling water, the Water Authority is in for a tight budget year.  

Denham has been positioning the Water Authority as something of an entrepreneur on the river. San Diego has plenty of water supplies, and the prices to prove it. Now it’s facing mounting costs to maintain its system as well as pay for all those water contracts. It recently lost two of its 24 member agencies to another water supplier, blamed mostly on the rising cost of San Diego’s water.  

The city of San Diego, facing its own expensive water recycling project, has pushed Water Authority leaders to sell off some of its water contracts like desal. But it’s unclear whether the push for a plant expansion will also appease Water Authority customers.  

Denham responded to this conundrum by making new deals. In November, San Diego, Los Angeles and Imperial Valley made a three-way water swap (possible in large part due to an infusion of federal cash and lots of recent rain). San Diego forwent buying some of its Colorado River water and bought California water instead. Denham said those parties are hoping to replicate that in the next few years as the West draws nearer to a 2026 deadline where users must come to consensus on drastically reducing Colorado River water demand. 

“We’ll be talking about desal and I’ll be advocating for more flexibility in transferring this water,” Denham said. “It really is the future of water in southern California.”  

Clarification: This story has been updated to note that Coast Law Group is a law firm that has represented environmental groups.