As desalination gains traction in parts of California, Santa Cruz weighs future of its water supply

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When it comes to the view of desalination as a tool to drought-proof local water systems in California, 2022 has been a roller-coaster year.

In May, the California Coastal Commission, a 12-member appointed board responsible for overseeing the state’s 1,100 miles of coastline, rejected on environmental grounds a $1.4 billion desalination facility proposed for Huntington Beach.

Amid that rejection, the commission acknowledged that desalination needed a closer look as a tool to bolster the state’s water supply in a future predicted to be drier, hotter and thirstier. Six months later, the commission turned around and approved two desalination facilities, one in Orange County and another along Monterey Bay in Monterey County.

Then the prospect of desalination encroached even closer to home, when the Santa Cruz City Council on Nov. 29 approved a water-supply strategy that listed desalination as one of four water-supply projects on the table to secure the city’s water system in an increasingly uncertain climate future.

“As long as the Pacific Ocean is sitting in our front yard, desalination cannot go away as an option,” Santa Cruz’s water director, Rosemary Menard, said. “It can be done but it’s not the first thing we’re going to focus on. It’s a complicated strategy to pursue.”

Whether desalination is a realistic option for Santa Cruz is up for debate, but the Nov. 29 vote added yet another leg to the strategy’s complicated political journey in the city over the years. Desalination, though codified as a possible avenue, has not been publicly supported as the priority project. However, 2023 will see the Santa Cruz City Council begin the process of vetting the water-supply options in front of the city.

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Today, Santa Cruz gets 95% of its supply from surface water of the San Lorenzo River watershed. In a future with extreme, five- to 12-year droughts, supply from that watershed could slow to a trickle and the city would need to tap into other sources and reserves that don’t depend on rain during these extended dry periods.

The water-supply policy Menard and the Santa Cruz Water Department presented to the city council in November centered around the city’s vulnerability in water-storage capacity, and the critical need to cushion supply. The policy sets a goal of adding 500 million gallons per year to the local water supply by 2027, a roughly 20% increase over existing annual demand. The long-term plan, however, is more extreme.

Almost all of the city’s water storage is contained in Loch Lomond, which, at just under 3 billion gallons in capacity, is a little more than what’s needed to get Santa Cruz through a drought year. One year’s worth of reserves does not offer adequate security in a future of multiyear droughts. By 2045, Menard’s team estimates Santa Cruz will need the ability to have an additional 2.2 billion gallons of available water on hand for the city to comfortably weather droughts and continue to grow as planned.

Menard says the immediate focus will likely be on expanding storage capacity and the city’s ability to capture and store excess stormwater during wet winters. Another option is to recycle wastewater into drinkable water, easing the pressures on the city’s surface water sources.

Yet both of these options require, at least at some point, enough rain to fall. This is where desalination comes in as an option. The strategy doesn’t require rainfall as it draws water from the Pacific Ocean.

Desalination, however, takes years of planning and permitting, is energy intensive, expensive and, in Santa Cruz, would require a popular vote before the city council could move forward in pursuing it.

According to estimates from the city’s water department, desalination could cost up to $443 million in capital costs and no less than $6.8 million per year to operate, while also requiring 17,500 megawatt-hours of electricity per year — equivalent to power needed more than 1,600 homes for a year, based on federal estimates. The numbers dwarf those of other water-supply options, such as the stormwater capture and storage, known as aquifer storage and recovery (ASR), which is estimated to cost $96 million in capital costs and require 930 megawatt-hours per year.

Santa Cruz has tried to pursue desalination in the past. Eileen Cross, spokesperson for the city’s water department, says the city, in a partnership with the Soquel Creek Water District, put $11 million into a yearslong process of getting a regional desalination proposal through the environmental-clearance stage. However, pushback from the community culminated in a 2012 ballot measure — Measure P — that sought to codify a rule that any desalination project for the city of Santa Cruz must be first approved by the voters. Measure P passed with more than 72% of the vote.

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Although the lopsided vote showed residents wanted a say in whether the city pursues desalination, it did not offer a clear picture of whether residents want desalination. Nonetheless, in 2013, the city council decided to shelve the ongoing desalination project and create a Water Supply Advisory Committee, a 14-member appointed body that would engage the public and find which supply options strike the right balance of technical and political feasibility.

The water supply policy adopted by the city council on Nov. 29 is a direct descendant of the work of the Water Supply Advisory Committee. Rick Longinotti, who sat on the committee, said although desalination is listed as an option, “it’s the least likely to be implemented.”

“The public would need to feel confident that the other options were first explored fully and implemented before desalination,” said Longinotti, who sees desalination as an unsustainable electricity hog and heavily favors expanding the city’s ability to capture and store excess rainwater. “I will certainly do my part in advocating that the city implement the much more sustainable alternatives. What we want to do for the next generation is make things more sustainable and not so energy dependent.”

One of new Mayor Fred Keeley’s most prominent campaign messages was the need to “drought-proof” the city’s water system. Now that the city council has adopted a broad water-supply policy, Keeley sees 2023 and beyond as “project selection time.” He is looking at all options “with an open mind,” but isn’t ready to throw his support behind one project over another yet.

“The key for me is that our general plan vision [for development] is not held back by water-supply issues,” Keeley said.

The mayor also acknowledged that a lot has changed since the city previously pursued desalination in earnest. The coastal commission and Gov. Gavin Newsom have warmed up to the technology, and changes to that technology have played a major role. Both desalination plants approved by the coastal commission in 2022 are designed to draw ocean water in from subsurface wells, diminishing the environmental impact on marine life. Earlier desalination plants draw water directly in from the ocean’s water column, putting marine life at risk of being sucked up with the water.

Whether desalination is eventually pursued will be up to the city council and Santa Cruzans together. However, Menard maintains that, for now, it is “last on the list” of options ahead of Santa Cruz.