California Coastal Commission eyes desalination policy in 2018

STATEWIDE — The worst of California’s most recent drought cycle might be over, but policymakers are still contemplating desalination as a potential solution to future water shortages. Members of the California Coastal Commission, contemplating its 2018 agenda, held a study session on desalination at its final meeting of 2017.

Some of the questions Coastal Commission members will face as they devise a desalination policy during the next 12 (or more) months including how water will be sourced at new plants and how saltwater conversion plants affect marine life.

Tom Luster, a senior environmental scientist with the Coastal Commission, provided a detailed, technical presentation of seawater desalination and its potential impacts. Much of his presentation focused on subsurface intake designs and other ideas to draw open water into a desalination plant with minimal loss of marine life.

Luster said various federal and state policies, such as the Clean Water Act, Coastal Act and State Water Code, have all carry a similar goal in governing desalination plants on the coast: “Don’t kill marine life if you don’t have to.”

“In seawater there are planktons. That’s the basis of one of the key environmental issues we deal with in citing, designing and permitting seawater desalt facilities. Seawater is full of plankton … [and] is not just water,” Luster told commissioners. “[Seawater] is habitat for a rich variety of small organisms, most of which we know very little about. Basically, planktons are organisms that drift with the currents.”

Other life forms potentially affected by desalination plants and intakes are fish eggs, larvae and early stage crabs.

Damon Nagami, a senior attorney with the Natural Resources Defense Council, said desalination should take a back seat to what he identified as more efficient and practical drought solutions.

“California’s top priority for drought relief ought to be securing affordable, cost-effective, resilient and environmentally sound alternatives that we know will work, such as conservation, efficiency, stormwater capture and recycling,” Nagami told commissioners. “NRDC is not categorically against desalination [but could support it] as a last resort, where it’s needed.”

Nagami went on to explain desalination as a potentially “an expensive, energy intensive and environmental risky water supply option and may not be the best use of scarce water plans, especially in regions where water sustainability remains a distant aspiration.”

Desalination plants could also pose threats to California’s networks of Marine Protected Areas, according to Nagami.

Ray Heimstra of O.C. Coastkeeper said open ocean intakes are obsolete technology. He added the use of wedgewire screens to protect marine life from being sucked into desalination plants was found to be ineffective by the State Water Boards.

“Most of the marine life is very small. Those screens don’t do much,” Heimstra said.

Open ocean intakes also produce chemical additives and wastewater discharge, Heimstra told commissioners.

Brine discharge is yet another potential consequence of desalination plants. Heimstra said brine discharge should be comingled with wastewater as to not create newly polluted areas.

“The screens, although they’re one-millimeter slots, very small slots, about the thickness of a credit card, most plankton are still able to get through,” Luster told commissioners.

Open intakes with one-millimeter slots are the standard for plants required to use them over other technology, according to Luster.

The Coastal Commission will revisit its desalination discussion later this year.