CCC to rule on Cambria desalination plant studies

California Coastal Commission (CCC) staff have advised the commission at its meeting this week to agree to a US Army Corps of Engineers proposal to test a beach in the Cambria region, near San Luis Obispo, for use as beach wells for a desalination plant.

The CCC report, however, suggests two conditions: any mechanized work should be limited to September and October; and the Corps should conduct additional water quality monitoring to ensure the project’s pump tests were not mobilizing contaminants and discharging them into coastal waters.

In April 2009, the Corps announced that it would receive US$ 2.5 million in funding through the new American Recovery & Reinvestment Act to develop the Cambria desalination project. Features of the proposed 1,600 m³/d plant could include a solar plant to offset its energy consumption and horizontal bored intakes beneath the ocean floor. Cost estimates are in the region of US$ 16 million.

The project site is between the estuarine waters of the Santa Rosa Creek Natural Preserve, which is part of the State Park, and the offshore waters within the Cambria State Marine Conservation Area. Both areas provide rich habitat for numerous species.

The beach was selected as a possible location for intake wells based on the likely presence of submerged “paleochannels”, which are the buried former channels of coastal waterways. A 2008 seismic and ground-penetrating radar study done for the CCSD found preliminary evidence of three such channels beneath the beach. These areas contain permeable gravel and sand deposits that may be suitable for siting intake wells that can pull in subsurface seawater without disturbing marine life found in the nearby open waters of the ocean or estuary.