How much will water cost from a Doheny desalination plant? South Coast board hears options

South Coast Water District’s board of directors received new details about a proposed desalination facility during a workshop Tuesday in Laguna Beach.

A 30-year loan and $10-million grant could be obtained, while multiple sources of power, including natural gas, could help fuel the plant as part of the Doheny Ocean Desalination Project.

Mark Donovan, senior engineer with GHD, Inc., briefed board members on alternative power supplies, potential hazards from sea-level rise and projected costs of water for various ownership scenarios at the proposed plant.

South Coast, which serves customers in South Laguna, Dana Point, San Juan Capistrano and San Clemente, is proposing a 5-acre facility on 30 acres of district-owned property near San Juan Creek that would produce 4 million to 5 million gallons of potable water per day, with the possibility of increasing the output to 15 million gallons per day.

Water would cost $2,169 per acre foot with a facility that produces 5 million gallons of water per day under a public-private partnership, Donovan reported. An acre foot is equal to 326,000 gallons, or enough water to cover an acre of land 1 foot deep, according to the nonprofit Water Education Foundation.

In this scenario, a private company would shoulder the cost for development and construction while the district would pay for water once it is delivered.

Poseidon Water, which is working on getting approval for a desalination facility in Huntington Beach, approached South Coast last year about a partnership.

Water would cost less for a district-owned facility that produces 5 million gallons per day while under a 30-year loan with a 2% interest rate — $1,465 per acre foot.

In the coming months the district must decide whether it wants to partner with a private company and/or team with other public entities to help spread costs of a desalination facility.

“I struggle with the concept of building a plant that will provide, day in and day out, more water than this district can use,” board member Dennis Erdman said. “I’m happy to see a 3-million-gallon-per-day option.”

Donovan provided options for a facility that produces 3 million gallons of water per day.

The district imports 80% of its water from the Colorado River and Northern California. The remaining 20% comes from recycled and groundwater sources.

Cost estimates for design and construction have ranged from $70 million to $90 million.

Board member Bill Green said it may be time to see if surrounding cities would like to partner with the district on the project.

“It’s time we start contacting, now that we have dollars in front of us,” Green said.

Under the proposal, crews would drill wells extending from Doheny State Beach to draw water from under the ocean floor rather than in open water.

The next board workshop on the Doheny facility will begin at 3 p.m. on Nov. 15.

bryce.alderton@latimes.com

Twitter: @AldertonBryce