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New desalination plant proposed for SLO County

Posted at 7:37 AM, Sep 28, 2022

The words “drought-proof water supply” almost sound too good to be true, but there is a proposal in the works on the Central Coast for a water supply that does not rely on rain.

The San Luis Obispo county public works department is kicking off a project that aims to bring large-scale desalinization to the Central Coast to supplement our water supply long term. While the plan is just in its starting phases the next steps are already laid out.

The Central Coast relies on a combination of rainfall, reservoirs, and groundwater to fulfill our water needs but as droughts and water insecurities continue to increase the county is planning for another source of water, this time from our ocean.

Courtney Howard, the San Luis Obispo County Public Works water resources division manager told us why this is something they are looking into. "With the changes, we're seeing and the rainfall patterns, we are looking for a drought-proof supply."

Part of the solution may be desalination, an energy-intensive process that takes salt water from our oceans and removes the salt through distillation eventually producing fresh water and salty brine.

Jacopo Buongiorno from the MIT Nuclear and Engineering department has worked on projects surrounding desalination on the Central Coast. He told us, "the ability to desalinate water and use that fresh water for agriculture or residential or even replenishing the aquifer would be certainly a positive a positive development."

In San Luis Obispo County, 88 percent of our water comes from groundwater sources, 10 percent from reservoirs and lakes, and the remainder from the state water project and recycled water.

Howard continued, "we see a lot of competition with our watersheds and groundwater basins and all who depend on that rainfall. And if those rainfall amounts are not filling our reservoirs and our groundwater basins like it has in the past, then we need to look at another source of supply so we can relieve some of that pressure on those systems"

The public works team will be taking a recommendation to the San Luis Obispo County Board of Supervisors in October to begin the planning process for a county desalination plant.

Bungiornio explained that this, even at the quickest timeline will be a long-term project. "Naturally, that would not be very near-term. It would be a little bit longer term because it does entail the construction of a desalination plant on site that at the moment does not exist."

The timeline of this proposal is long-term. Here is a look at the proposed "Path to Desalination"

Before the county can build or repurpose a desalination plant it must create partnerships with other water districts, evaluate locations, create a budget, and compile input from the public.

Howard continued, "we think it'll take a while to get all of that information gathered and vetted. So probably in about ten years, 5 to 10 years in that time frame. So there will be a lot of different tracks to evaluate, you know, sitting technology partnerships. And so we'll have public meetings to get input along the way."

Potential distribution, emergency plans, technology improvements, and currently available locations are all being considered. Once the plan is approved the board can move on to acquiring specialty engineers and consultants.

Howard explained, "I think it's important to get started now, and we're going to have a lot of opportunities for public engagement, and we encourage folks to get involved and send us their thoughts and concerns so that we can make sure we consider them as we go along."

The public is invited to share their opinions about the plan on October 18th at the county supervisor’s meeting.