As California's drought continues to intensify, coastal cities are looking to the ocean as a potential means of supplementing a dwindling reserve of fresh water.
Construction of what's being billed as the largest desalination plant in the Western Hemisphere has been underway for nearly two years in Carlsbad. Two other treatment facilities, in Oceanside and at Camp Pendleton, are among 11 new projects being considered throughout the state.
In response to the newfound interest in harvesting seawater, the California Water Resources Control Board has been working to draft a streamlined set of regulations for review and approval of desalination projects. To date, each proposal has been reviewed on a case-by-case basis. On May 6, the board voted to approve its draft regulation.
Water-quality activists with California Coastkeeper immediately cried foul. They claim the guidelines, based off the Carlsbad project, will "utilize practices predicted to kill billions of marine organisms, cost ratepayers and municipalities more money than alternative water sources, produce more pollution, and impact marine ecosystems more severely than is necessary."
Once the salt is separated from a portion of the water pumped through a desalination plant to be retained for fresh-water use, the remaining highly alkaline "brine" is pumped back to the ocean via a discharge channel where it mixes with other seawater. Marine-life advocates are concerned that the extra salinity could have a negative effect on coastal wildlife, especially for creatures along the sea floor where sediments from the discharge could settle.
Coastkeeper's San Diego chapter has long advocated for fresh-water conservation measures, potable reuse, or wastewater recycling, touting the practice as cheaper and more environmentally sound. The City of San Diego is already moving forward with such a program, following a successful pilot run in 2010.
"Ocean desalination is not an effective drought response," says Coastkeeper executive director Sara Aminzadeh. "Desalination facilities are constructed under enormous cost to ratepayers, and often go unused. The desalination policy adopted creates a framework for local entities to consider and mitigate facility impacts to the ocean, but aside from environmental impacts, desalination is almost always the most costly and energy-intensive source of water."