Diablo desal expansion, South County sewage recycling get official support

Two South County water projects — that could provide some 2,000 acre-feet of supplemental water for the Five Cities area each year — enjoyed broad support among San Luis Obispo County Supervisors and city officials on Tuesday.

“Our water supplies are in critical condition,” said Greg Ray, Grover Beach Public Works director. “The time to act is upon us.”

The Board of Supervisors held a South County water study session in their hearing chambers on Tuesday that was attended by officials from Arroyo Grande, Grover Beach, Pismo Beach and Oceano to discuss two projects that could help the drought-depleted region.

With Pismo Beach serving as the lead agency, South County cities are planning to build a wastewater reclamation project that would inject as much as 1,200 acre-feet of treated wastewater into the Santa Maria groundwater basin. About 700 acre-feet would be drawn from the basin each year, allowing it to recharge and help prevent saltwater intrusion.

County Public Works staff is preparing a feasibility study for the second water project — an expansion of the desalination plant at Diablo Canyon nuclear power plant. By adding more reverse osmosis modules, the plant could produce as much as 1,300 acre-feet of additional water.

A 7-mile pipeline connecting the desalination plant to the Lopez Lake pipeline would also have to be built. The desalinated water could be available as soon as 2017. A report to the Board of Supervisors on the project is scheduled for March 22.

The South County is facing a water crisis because Lopez Lake is at only 29 percent capacity, the groundwater basin is overpumped, and deliveries from the State Water Project have been unreliable in recent years.

“This is an extremely important problem going forward,” said Arroyo Grande Mayor Jim Hill. “We are moving in the right direction, and we have two very good paths forward.”

Mark Hutchinson, deputy public works director, said the county is also looking at the feasibility of cloud seeding. This consists of releasing particles from airplanes, such as silver iodide, around which raindrops can condense.

Studies have shown that cloud seeding can increase rainfall by as much as 20 percent, Hutchinson said. If the county pursues this option, it would work in collaboration with Santa Barbara and Monterey counties. Santa Barbara County has been doing cloud seeding since 1981.

Although the Central Coast is in a strong El Niño weather pattern, the anticipated heavy rainfall has not yet materialized. January was a wet month, but that rainfall only caused slight increases in reservoir levels. This is because, after four years of drought, conditions in the county remain extraordinarily dry. Lopez Lake is expected to be at just 20 percent capacity by fall, Hutchinson said.

February has been mostly dry. City and county officials said they are hoping for a Miracle March. Storms are predicted for the first week of March.

This story was originally published February 23, 2016 at 5:28 PM with the headline "Diablo desal expansion, South County sewage recycling get official support."