Orange County Desalination Plant

By November 14, 2018 March 19th, 2019 No Comments

Providing enough water for southern California been a concern since the area began to urbanize in the first years of the 20th century.  Much of southern California’s water has since been imported from the Central Valley, the Owens Valley, and the Colorado River, with snowpack melt in the Sierras being the ultimate source for the former two.  Below average rainfall across California, combined with the snowpack in the Sierras decreasing over the past decade, has increased interest in alternate sources for southern California’s growing water demand.  For instance, Lake Mead on the Colorado River is currently at Shortage Trigger Level – 1,075 feet elevation.
On September 18, 2018, John Kennedy, Executive Director of Engineering and Water Services of the Orange County Water District (OCWD), delivered a presentation of the status of the proposed Huntington Beach ocean desalination project.   The presentation was made to the Groundwater Resources Association, southern branch, at the OCWD headquarters in Fountain Valley.  In the early 2000’s, OCWD began considering a desalination plant to alleviate the increasing water demand by Orange County’s growing population.  In 2010, OCWD and other water agencies entered into a confidentiality agreement and Memo of Understanding with Poseidon Water, a builder of desalination plants.  Poseidon has since constructed a desalination plant in Carlsbad, in northern San Diego County, and has operated it since 2015.
The Orange County desalination plant would be situated in Huntington Beach, adjacent to the AES electrical plant.  According to Poseidon, the plant would be able to provide 50 million gallons of water per day, or 56,000 acre-feet per year.  The term of the contract between the OCWD and Poseidon would be either 30 or 35 years.  Poseidon would build the plant, and OCWD would build the distribution system.
The plant would operate by installing an intake pipeline that would extend to 1,840 feet offshore.  The outfall pipeline would extend to 1,500 feet offshore.  The screen on the intake pipe would be a one millimeter screen mesh, to minimize the intake of marine organisms.  At the terminus of the outfall pipe would be a diffuser.  The outgoing water would be 2 parts per thousand above the ambient ocean salinity.
Besides reducing the need for imported water from northern California and the Colorado River, the desalination plant would provide water with lower Total Dissolved Solids (TDS) than imported water.  Finally, after the contract expires, OCWD would own the plant.
There has been concern whether the cost of the desalination project would ultimately pay for itself – and then decrease the cost of water to OCWD customers – or would it wind up costing more to build and operate the desalination plant than to continue to import water.  The point at which the project would pay for itself depends on how much money the Metropolitan Water District of Southern California contributes to the cost of the project.  The Metropolitan Water District of Southern California is a regional wholesaler that delivers water to 26 member public agencies – 14 cities, 11 municipal water districts, one county water authority – which in turn provides water to 19 million people in Los Angeles, Orange, Riverside, San Bernardino, San Diego and Ventura counties.  Depending on the amount that the MWD contributes, the cost of the plant would be recouped as early as 2035 (or, if less money is contributed by MWD, not until after 2050).  After that point, water produced by desalination would be less costly than imported water.  However, if the MWD decides to contribute nothing, then it is accepted that the plant would not be able to be built.
So, where does this project stand now?  Poseidon needs to complete the California Environmental Quality Act (CEQA) requirements.  The OCWD also needs to negotiate with the other water districts in southern California that want to participate in this project.  And, ultimately, the MWD – which has authority over virtually all the water in the southern portion of the state – would deliver the final verdict as to whether the project would go forward.
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