Desalination as way to help solve state's water problem is inevitable

“Water, water, every where,/ Nor any drop to drink.” — “Rime of the Ancient Mariner,” Samuel Taylor Coleridge, 1798

It has taken an unprecedented series of multiyear droughts, conversion of thousands of California lawns to water-sparing cacti and other plants and stricterthan-ever water rationing in many parts of the state, but at last it's beginning to look like Coleridge's mariner may have been premature.

There's plenty of Pacific Ocean water being drunk in California today, with every indication suggesting there will be much more to come. California will likely never be like Israel, drawing 90% of its drinking water from desalinated sea water, but it's probable now that eventually such purified brine will make up something more than 10% of the state's supply.

This looks like a simple necessity. As the state insists on more and more dense residential construction and as snowpacks in the Sierra Nevada become thinner over the decades, this state will have to brace for spending big money to provide water for its population of about 40 million.

Yes, that population was down a little over the last two years, as some folks migrated to other states and fewer of the foreign-born came here during the worst COVID-19 pandemic years. But these look like minor and probably temporary phenomena compared with the full scope of urban California. No one has seen any notable declines in either traffic jams or crowds in pedestrian-only areas in spite of the state's recent loss of one seat in Congress.

Plus the rest of California has seen that San Diego County, with the Poseidon Water desalination facility at Carlsbad producing allout during the drought, was better off water-wise than many parts of the state. That came at a price, of course. The Poseidon plant, making about 48,000 acre-feet of purified water yearly (more than 1.5 billion gallons), accounted for almost 10% of San Diego County's water at a price of about $2,750 per acre-foot.

At one time, the price tag seemed to make the cost of desalination prohibitive elsewhere in the state. At the time the Carlsbad plant was finished, supplies from the California State Water Project were being sold to some agencies for about $700 per acre-foot. Desalinated water thus cost about four times as much as aqueduct supplies.

However, the state's aqueducts and the reservoirs they once filled have run at depleted levels for the last two years, and the cost differences of various types of water are beginning to narrow. Drought has caused the Metropolitan Water District of Southern California, the state's largest water wholesaler, to sell treated supplies for about $1,200 per acrefoot over the last year, still not close to the cost of desalinated water, but much closer than it was only about six years ago.

Plus much desalinated water from the state's other purifying plants now sells for less than Poseidon's supplies — more in the neighborhood of $2,000 per acre foot. That's one reason the state Coastal Commission last year approved building a new desalination plant near Doheny State Beach, close to Orange County's Dana Point. This facility would produce about 5 million gallons daily, significantly less than the Carlsbad plant, but still a boost for local supplies and a kind of insurance policy.

As technology improves, allowing desalination to kill fewer marine animals and organisms while producing less brine, more plants will be approved. This will be especially true if droughts persist and provide political pressure to green-light desalination projects. New technology also includes experiments with widely-spaced desalination buoys to decentralize the process so no ocean areas are overloaded with either thick brine or dead flora and fauna.

As usual, necessity has become the mother of invention: To survive, California must have more desalination plants if drought and population levels persist. For sure, the political imperative is there: A July survey by the Public Policy Institute of California found three-quarters of likely voters believe droughts are a big problem. Expensive as it may be, that cannot help but thrust desalination to the fore as a big part of the solution.