Thirsty cities look seaward for more water

Posted: 7 April 2003

As California and other thirsty [US] states face a seemingly endless search for more water, one possible future is already here: a desalination plant that sucks salty water out of the sea and transforms it into drinking water. This report from the Washington Post looks at the potential for the oceans to meet that country's growing water crisis.

Think of the ocean, says Rich Youngblood, the City of Marina's conservation director, patting the pipes of his municipal water-making factory, as "the world's largest reservoir." Once seen as prohibitively expensive and technologically troublesome, large-scale seawater desalination is now poised to become a reality, as such states as California, Texas and Florida scramble for new sources beyond the traditional reservoirs, aquifers and rivers.

Although California is not about to become Saudi Arabia, the desert kingdom that gets 70 per cent of its water from the ocean, there are desalination plants proposed or planned in 13 sites along the Golden State's coast - an investment that could run into billions of dollars, and for some water districts could account for 10 to 20 per cent of their needs over the next two decades.

The technology could also up-end the long-running water wars between town and country, giving the fast-growing coastal cities new clout - and the ability to keep growing.

It has often been assumed that sooner or later, many places, like Los Angeles, would simply run out of new water - but desalination has the potential to change that equation, for better or worse. "It's a real revolution," said Barry Nelson, a senior policy analyst and water expert with the Natural Resources Defense Council, an environmental watchdog.

"Desalination has gone through a transformation. Once pie-in-the-sky, almost completely impractical. But now it is entering the mainstream of real-world options."

World's largest

The largest desalination plant in the Western Hemisphere will soon begin operating in Tampa, producing 25 million gallons of drinking water a day - or about 10 per cent of the city's needs. In Texas, the Republican Governor, Rick Perry, directed his state water development board to develop plans to operate desalination plants along the Gulf of Mexico.

Nine water districts have submitted proposals to meet demands in south Texas. In New Mexico, a federal project will explore how to desalinate not ocean water, but the underground aquifers in the southern part of the state, which hold a vast amount of saline water.

Desalination works by pushing salt water at high pressure through plastic membranes that filter out and remove the salt molecules. For every two gallons into the plant, out comes one gallon of fresh water and one gallon of brine. In recent years, the membranes have gotten cheaper and more efficient, but making fresh water from the ocean is still very energy-intensive.

Many urban water agencies are struggling to conserve and recycle water, but there are very few "new" sources of water. In recent years, the cities began to look to buy water from inland farmers, but those negotiations have been highly controversial, as they require farmers to allow fields to lay fallow.

Environmental damage

The most recent example is the stalled deal between San Diego and the Imperial Irrigation District in southeast California. The accord collapsed over who would pay for the possible environmental damage that would result from diverting the agricultural runoff that otherwise would drain into the Salton Sea, a lake that is a vital pit stop for migrating waterfowl.

"The demand for water is enormous and growing. That's what makes desalination part of the future," said Steve Erie, a professor of political science and a water expert at the University of California at San Diego. "If all of the other options are more expensive or limited, we will turn to desalination, and we will simply pay more," Erie said. "We'll look west, to the Pacific Ocean."

The Bush administration recently slashed the Colorado River water allocations of thirsty cities in Southern California. After years of taking more than its fair share from the other six states that rely on the Colorado, California was cut off from its access to extra water. With the Colorado River flows reduced, desalination is now seen as competitive -- when compared with the financial and environmental costs of building new dams and reservoirs, or importing water from farms to cities.

"There is no cheap water anymore," said Adan Ortega Jr., a vice president with the Metropolitan Water District of Southern California, the largest in the nation, which serves about 18 million people in six counties. The water district is planning to subsidize the construction of at least five desalination plants in the coming decade, and the agency's planners forecast that about 7 per cent of the region's needs will be met with formerly salty water.

Various advantages

The first and largest project is slated to be completed by 2007 in Carlsbad in northern San Diego County, a $270 million plant that will be larger than the one in Tampa. "Seawater desalination will be a critical resource in our water-supply future," said Bernie Rhinerson, chairman of the San Diego County Water Authority board.

Rhinerson said that desalination offers several advantages: It is drought-proof and reliable. It has been identified as the best alternative for providing a new supply of safe, reliable water for the San Diego region in its latest master plan. After the Carlsbad facility is completed, two more major desalination plants are planned. San Diego County plans on getting as much as 15 per cent of its water from the ocean.

Creating fresh water from salt is still expensive - and it has other problems. Environmentalists worry about dumping super-salty brine back into the ocean, about unsightly water factories built along the beaches and about the smog from power plants providing electricity to run desalination facilities.

Bob Yamada, seawater desalination manager for the San Diego County Water Authority, said the Carlsbad facility should be able to produce an acre-foot of water for about $800, plus another $100 per acre-foot to build new pipes to move the fresh water from sea level, uphill and inland to the users.

An acre-foot of water is the industry standard, equaling about 326,000 gallons or the amount that two urban households consume in a year. Buying imported water from farmers in the Imperial Valley would have cost San Diego around $250 to $300 an acre-foot, so desalination is clearly costly. (The same amount of bottled Evian water would cost about $1.4 million).

But Yamada points out that the cost should be measured against the creation of "new" water, meaning the cost of building new dams, reservoirs, wells and recycling plants. The first desalination plants will probably be built next door to existing coastal power plants, to reduce environmental impacts and eyesores.

In Marina, where the little desalination plant produces about 13 per cent of the city's water needs, manager Youngblood stands beside a vista of the vast Pacific. He recites a figure he recently read. Three per cent of all Earth's water is fresh, in the lakes, rivers and beneath the ground. All the rest, Youngblood said, is in the oceans.

Washington Post 30th March 2003