The status of the Bay Area Regional Desalination Project was presented at the Redwood City Council Chambers Tuesday to instigate a public discussion regarding using desalinated water to address regional water shortages.
The San Francisco Public Utilities Commission, East Bay Municipal Utility District, Contra Costa Water District, and Santa Clara Valley Water District have been studying the feasibility of desalination as a regional water supply source since 2003, while Zone 7 Water Agency joined the collaboration in 2010.
The agencies have collectively spent $2.3 million in studying desalination.
“Desalination is not looked at as the only option, but part of a portfolio” said Manisha Kothari, project manager at the San Francisco Public Utilities Commission.
Conservation, Kothari said, will continue to be priority for the Bay Area’s largest water agencies.
At this point, no agencies have made any decisions at this time regarding the use of desalination, Kothari said.
According to Kothari, the process of desalination, which removes salts from ocean and bay water to produce fresh drinking water, is costly but has major benefits to the adjoining water agencies.
Desalination is not curtailed by drought, water pipeline failures, it would be less affected by major earthquakes, and would often be the more dependable choice of water supply in times of emergency, Kothari said.
“Desalination provides a reliable source of drinking water unlike other alternative supplies,” she said.
According to Ray Wong of the Santa Clara Valley Water District, the cost of desalinated water would be approximately $1,000 per acre-foot compared to $400 per acre-foot using pumped groundwater.
“It’s more expensive,” Wong said. “But we’re trying to look at different sources and alternatives.”
In April 2009, the project began a six-month pilot test at the Contra Costa Water District’s Mallard Slough Pump Station. The test, Wong said, demonstrated that desalination was technically viable and brine toxicity had no effects on local species, but there could be a possible impact to the Longfin and Delta Smelt fish species in local waters.
Environmental activist groups have been wary of the process of desalination in the past.
Josh Sonnenfeld of Save the Bay said he was concerned about potential impacts desalination could have on surrounding natural habitats .
“We don’t know what the intake of all that water will do to wildlife,” he said. “We can’t assume we can just keep taking water from the Bay forever.”
David Smith, the Vice President of the development company DMB Pacific Ventures, said that they have never proposed desalination as the solution for the project's water supply.
Emily Corwin, junior engineer at Contra Costa Water District, said the percentage of desalination in the overall water supply of the Bay Area would be minimal but would be beneficial to diversify water sources.
Recycled water programs are also being strongly considered throughout the Bay Area, she said.
“All of the agencies are evaluating recycled water in parallel with desalination,” she said. “It’s not an either, or situation.”
According to Wong, the collaborating agencies will now continue to study desalination in terms of greenhouse gas analysis, hydraulic modeling, delta modeling and storage optimization at a cost of $1 million, which will be equally shred among the five agencies.
Each agency is expected to make a final decision on agency participation in the use of desalination by June 2013.
Until then, the agencies will continue to study the feasibility of desalination alongside other potential water supplies.
“Desalination is just one of many tools to address water shortages,” Kothari said.