Winter storms have walloped California this year, and snowpack is【C1】_____up. But just a few years back, the state was wrung dry by a record-breaking drought. And more dry spells will【C2】_____come.

“I think everybody agrees that we need more water resources.” Adina Paytan, an oceanographer at the University of California, Santa Cruz. She【C3】_____out that her home country, Israel, faced the same problem. “Israel had water issues for ever and ever. They don’t have water issues【C4】__because they【C5】_____pretty much 90 percent of water use to desalination.”

Ocean desalination hasn’t enjoyed as much【C6】_____in California due to its cost, and because of concerns that the plants would damage coastal ecosystems—both when seawater is【C7】__in, and when leftover super-salty brines are【C8】__. Now, writing in the journal Water, Paytan and her team have assessed the【C9】_____ impact of the nation’s largest plant: the Carlsbad Desalination Plant, north of San Diego.

Here’s the good news. Scuba dives revealed that the【C10】_____of starfish, snails, sea cucumbers and other creatures that live on the sandy ocean bottom offshore have not【C11】__since the plant opened in 2015. But the bad news? The plume of salty runoff stayed【C12】__much farther out than models predicted, rather than easily【C13】_____with closer seawater.

“When you have a pool of salty water that doesn’t mix, it【C14】_____oxygen from penetrating, so it can cause lower oxygen levels close to the【C15】_____and obviously, all the organisms that need oxygen are not going to be happy.”

Ecosystems offshore from the Carlsbad plant were already disturbed by cooling water【C16】_____from a power plant at the same site, she says, which could explain why the marine life was【C17】_____. But at more pristine sites, especially those rich in biodiversity like kelp forests, a salty plume might do more harm.

The state’s already planning more ocean desalination projects up and【C18】_____the coast. Paytan says her lesson is this: “There’s tons of water in the ocean. We can use it but we just have to do it【C19】__.” And the first step is to update our models of how salty wastewater behaves offshore in order to ensure that our【C20】_____ for drinking water doesn’t cause an ecological sea change.

【C18】