District officials counter that they will fully comply with all environmental requirements as part of the ongoing permitting process. They expect to complete the regular permitting process next year.
In the meantime, using the emergency permit from the county, they are pursuing what they are calling “a permanent emergency solution.” Under the emergency permit, the plant will only be permitted to operate during periods of Stage 3 drought conditions, which is the extreme emergency.
The plant design is based on a study by the U.S. Army Corps of Engineers that identified a brackish desalination plant along San Simeon Creek as the most technically feasible option. Brackish water is water that has more salinity than freshwater but not as much salt as seawater.
The idea is to meet the needs of the current emergency while, at the same time, build a plant that is permanent enough to be able to handle drought conditions and water shortages that could last for years, Bahringer said.
“It’s a health and safety issue,” he said. “People are suffering too much and we want them to get back to normal.”
However, state regulators and many in the community have been critical of this approach. In a strongly worded letter to the district, the California Coastal Commission said the district could have used a portable desalination plant like the kind used along the Gulf Coast in 2005 following Hurricane Katrina, which could have been up and running by July.
“Emergency permits are meant to be for the short term,” said Tom Luster, an environmental scientist with the Coastal Commission. “This has turned into something more elaborate and permanent.”
The district board looked at this option but rejected it for a variety of reasons, Bahringer said. These included the inability to get a loan to finance the portable unit as well as concerns that a more permanent facility would be needed.
The facility under construction is designed to be quickly installed by housing the filtration and treatment units and other equipment in shipping containers and installing distribution pipes above ground, said Robert Gresens, district engineer.
The plant could be easily modified if the district decides to make it truly permanent, Gresens said. These modifications would include installing solar panels to provide electricity and burying the pipes.
District officials also acknowledge that the desalination plant under construction is likely to become permanent, operating at least during droughts and other low-water periods. One of the main reasons for this is the fact that the district took out a 20-year loan to pay for it.
The use of brackish water rather than seawater for desalination is a growing national trend. The desalination plants in Sand City and Orange County as well as more than 100 plants in Texas use brackish water.
“Until recently, brackish water was not considered usable,” said Kyle Frazier, director of the Texas Desalination Association. “But with chronic drought conditions, it is suddenly becoming more and more useful.”
The advantage of using brackish water is that its salinity levels are often much less than seawater, making it cheaper to turn into freshwater. The water to be used in the Cambria plant is about 8 to 10 percent of the salinity of the ocean.
Using less salty water reduces the cost of running the powerful pumps used to filter the salt out, and reduces the stress on expensive reverse-osmosis filtering membranes. It also reduces the amount of salt residue that needs to be disposed of after the brine is evaporated.
The desalination plant will still have several potentially significant environmental impacts that the district will have to fully analyze and deal with once the plant is up and running.
Reference : www.sanluisobispo.com