In the News

Desalination: A Plan for Future Droughts

Wes Sims, KUSP News, 02/21/13

Podcast: Download (mp3)

“This is Ocean Street Extension and the river doesn’t always look or sound like this, but in a nice winter like this one, it’s a rather nice little sound,” says Santa Cruz Water Director Bill Kocher as we walked along the banks of the San Lorenzo River, the primary source of the city’s water supply.

“And if 90,000 acre feet moved down this river in one year that’s considered an average year. And already, from last October, we’re at 40,000 acre feet.”

An acre-foot is the volume of water that would cover an acre to a depth of a foot. Santa Cruz’s water district uses about 11,000 acre feet in a typical year. Usually the San Lorenzo River and the city’s wells provide enough. In dry years, the district has to let enough water flow down the river for fish to survive. Due to a recent order from the state, the amount or river water reserved for fish in dry years has increased. Meanwhile, the district can only take a limited amount from wells./p>

“If we had a drought today that looked like ’76-’77, we would be about 50% short for the average homeowner,” Kocher explains. “Just in terms of bathing, in terms of toilet flushing, in terms of outdoor irrigation, whatever they use water for. If they could imagine having half that amount available to them, that’s what would happen in a critically dry year.”

Dry Years are Where the Problem Lies

By imposing restrictions on water users, Kocher says the district can get usage down to about 9,500 acre feet. But the supply from the river and wells could fall 1,400 acre feet short.

“There’s really two things going on,” Kocher says. “One is that we are doing OK now in normal years. We’re not doing OK now in dry and critically dry years.”

Kocher’s plan has been to fill this drought-year gap with water from a 150 million-dollar desalination plant whose cost would be split with the Soquel Creek Water District. That district needs a new source to replace its well water supply or risk losing its wells to seawater intrusion. So during droughts, the Santa Cruz District would use the desalinated water to make up its supply gap. The rest of the time, the plant would provide water for the Soquel District. Taj Dufour, acting general manager for the Soquel Creek District explains the arrangement:

“Our plans are to pump this as frequently as we could to reduce our draw on the groundwater basin. And when the city needs it they would be in charge. So basically, whichever agency is using the plant would be responsible for the operational costs.”

A Rare Example of Cooperation

“In an era when you have two houses of congress that can’t talk across the aisle, it’s sort of a model for inter-agency, intergovernmental agency cooperation,” Kocher says.

But there’s plenty of disagreement outside the business model between the City of Santa Cruz and the Soquel Creek District. Santa Cruz voters in the November 2012 general election approved Measure P, requiring a future city-wide vote before the City of Santa Cruz can authorize a desalination plant. One of the organizers of Measure P was former electrical contractor Rick Longinotti, who is concerned in part about the contribution a plant would make to the district’s greenhouse gas footprint.

“it’s twelve times the energy to produce a gallon of water as our current water supply,” Longinotti says.

Longinotti wants the city to make more ambitious restrictions on water usage in dry years, rather than building a desalination plant.

Tomorrow during Morning Edition and All Things Considered we look at some of the ways desalination opponents propose for supplying water in droughts. 

© 2008-2013 scwd2 Desalination Program, All rights reserved.