By Sandra Dibble From UT San Diego

Private proposal for a plant in Rosarito Beach moves forward

Could water flowing through San Diego taps one day come from across the border in Mexico?

The answer is yes, if proposals to desalinate seawater in Rosarito Beach and pipe it to the United States become a reality.

“Power, gas, commerce, families, everything moves back and forth,” said Mark Watton, general manager of the Otay Water District. “Why not water?”

Watton envisions the day when two-thirds of the district’s water supply — about 20,000 acre-feet per year — comes from a privately operated desalination facility next to a federally operated thermoelectric plant in Rosarito Beach.

Behind the project is NSC Agua, the Mexican subsidiary of Cayman Islands-based Consolidated Water Co. The company’s proposal for a plant with the capacity to convert up to 100 million gallons a day, or 112,000 acre-feet per year — twice the amount of a desalination plant under construction in Carlsbad — has been moving forward in recent months after years of delay. The estimated cost would be more than $500 million.

On a parallel track, the San Diego County Water Authority is participating in discussions with Mexican water agencies on the possibility of a publicly owned binational desalination plant in Rosarito Beach. “We know that a plant can be built,” said Dan Denham, the authority’s Colorado River program manager. “The question is, what size the plant will be, is it going to meet just Mexican demands or broader U.S. demands, and how is the water going to get across the border.”

This is not the first binational a water supply project proposed for the region. In the 1990s, the San Diego County Water Authority was in discussions with the Baja California government over the possibility of building a joint aqueduct to carry Colorado River water. The project never moved forward, but it set the stage for another idea — a binational desalination plant.

A 2005 study by the water authority considered locations on both sides of the border, including Rosarito Beach. A preliminary feasibility study in 2010 “determined that yes, it would be feasible to have a desalination plant in Rosarito Beach,” said Sally Spener, spokeswoman for the U.S. International Boundary and Water Commission. “The big questions are, how much would it cost, and who would pay for it.”

Now drought and growing demands on the Colorado River are adding urgency to these questions. A 2012 U.S.-Mexico agreement on the Colorado River known as Minute 319 listed a binational desalination plant in Rosarito Beach as a potential new source of water.

“We are studying the complex mosaic,” of alternatives, said Roberto Espinosa, head of the Tijuana office of Mexico’s Comision International de Limites y Aguas. The commission and its counterpart, the IBWC, are leading the binational discussion on the potential of a plant.

On the table are questions such as costs, environmental impacts, whether a future plant would be financed public, privately or with a combination of the two, and whether it should be binational or exclusively Mexican, Espinosa said.

IMAGE: The Presidente Juarez thermoelectric plant in Rosarito Beach, a key component in proposals to build a seawater desalination plant that would supply both sides of the border. — San Diego County Water Authority

For more on this story go to: http://www.utsandiego.com/news/2014/aug/24/rosarito-Mexico-desalination-plant-binational/