Yet another plan has emerged for desalinating the vast brackish water supplies deep below the ground west of Albuquerque.

Commonwealth Utilities owner Paul Powers recently told The Albuquerque Journal that he hopes to round up $500 million in private investment money, drill as many as 60 wells in the Rio Puerco valley, build one or more desalination plants and eventually create enough drinking water to supply perhaps half a million new homes. The first phase of work could begin late this year or early in 2009, he told the paper.

Powers’ plan appears to be the most ambitious of three announced since Sandoval County struck water northwest of Albuquerque last year. The county and a California development company, Recorp Partners Inc., currently are testing water from two wells to determine the feasibility of removing enough salt to make it drinkable. Their long-term hope is to find a 100-year supply for 30,000 homes, county officials told the Independent in May.

More recently, Atrisco Oil & Gas announced that its partner, Tecton Energy LLC, discovered water while drilling for natural gas in an area due west of Albuquerque. Atrisco filed a plan with the Office of the State Engineer to tap the aquifer for 12,000 acre-feet a year — enough water for perhaps 50,000 homes. Company officials told the Independent last month they hope to start testing their water soon for its desalination potential.

If all three projects are successful, they could provide water for the region and then some. Powers’ plan alone calls for pumping 110,000 acre-feet per year, which is almost 36 billion gallons. In contrast, Albuquerque currently pumps about 24 billion gallons of drinking water per year from the aquifer that underlies the city.

But there are many "ifs" surrounding the projects that may take their toll, either technologically or politically.

Technologically, desalination is a no-brainer, said Kerry Howe, an associate professor of environmental engineering at the University of New Mexico. People have been turning seawater into drinking water for decades, in situations as varied as the oil-rich Middle East, nuclear submarines and coastal cities around the United States.

Two major hurdles face the Albuquerque-area projects automatically, Howe said, and both are linked to the amount of salt and other minerals in the water. The more salt in the water, the more energy it takes to remove it. And as more salt is removed, the waste removal becomes a major issue — one of the biggest issues facing inland plants, he said. "If you get three gallons of fresh water from every four of brackish, what happens to the other gallon?" Howe asked. It’s four times as salty and can’t just be pumped onto the ground. Coastal desalination plants can pump their salt-laden wastewater farther out to sea. "You can’t do that here," he said.

Some inland plants re-inject the waste water deep into the ground, far from its source, Howe said. That’s what El Paso has done after opening the world’s largest inland desalination plant. But that requires the underlying geology to be just right — porous enough to absorb millions of gallons of water, yet not connected to other water sources, he said.

The brine also can be pumped into evaporation ponds, but the remaining salts must be disposed of. Powell told the Journal he planned to sell the salt, but a Web posting on the blog WaterWired by Michael Campana, director of the Institute of Water and Watersheds at the University of Oregon, suggests it could be a substantial amount:

If you remove 10,000 mg/L from 110,000 acre-feet of water each year, that is about 1.5 million tons (1.35 billion kilograms) that has to be disposed of every year. Since volume is more important than weight or mass in terms of waste disposal, let’s assume the waste has the density of solid halite (mineral form of NaCl), which is about 2170 kg/cubic meter. So that waste will occupy a volume of 622,000 cubic meters or about 22 million cubic feet per year. That is a cube about 280 feet on a edge, or about 500 acre-feet of waste per year! That’s a conservative estimate because I assumed the waste could be treated as solid halite, when in fact in might be more of a granular material, like table salt.

Higher salinity also means higher energy costs, Howe said. The Albuquerque-area desalination plants might be able to use natural gas or electricity off the grid, or install their own wind and/or solar projects. But if the salinity content is too high, it may make the water too expensive to treat.

On the other hand, as the value of water rises, a desalination plant that doesn’t make economic sense now could become feasible in 10, 20 or 50 years, Howe said.

Yet another potential hurdle facing all three brackish-water proposals is the Office of the State Engineer, the agency charged with regulating water use in New Mexico. State law says the OSE has no jurisdiction over water that lies more than 2,500 feet below the surface. Powell, Atrisco and Sandoval County have said their preliminary tests have shown that their aquifers are below that level.

State Engineer John D’Antonio and others have voiced concern about the brackish water reserves, fearing they may be hydrologically connected to water sources that others already rely on and use fully. A bill introduced into the Legislature in 2007 by Albuquerque Republican Sen. Joseph Carraro called for the OSE to assume immediate authority over all deep aquifers, regardless of the salinity. It died in the Senate.

But there is fine print in the current law that suggests the OSE may actually control certain brackish water supplies. If the aquifer rises to 2,500 feet at any point, the OSE appears to have authority over the entire water body, said Blair Dunn, staff counsel at The WaterBank, an Albuquerque water-rights brokerage firm.

"No one’s challenged the law" regarding the OSE’s authority, Dunn said, simply because the matter has never come up before. And unless the Legislature changes the law to require otherwise, the OSE would likely have to prove that a given aquifer hits the 2,500-foot mark before assuming jurisdiction over it, he said.

If all of the Rio Puerco aquifers are indeed below 2,500 feet, the water appears to belong to whoever pumps it first — it’s the "law of first capture," said Dunn. Such is the case with all water wells in Texas. Under that legal strategy, oil magnate and wind-power enthusiast T. Boone Pickens says he plans to pump ancient water from the Ogallala Aquifer deep beneath the Panhandle and pipe it to homes and businesses hundreds of miles away, regardless of the effect on neighboring wells.

The rush to pump brackish water in the Rio Puerco area may have no effect on the other desalination plans or on water wells in Albuquerque and Rio Rancho. But there’s nothing to stop additional wells from going in, and nothing to prevent a Klondike-style gold rush for brackish water, Dunn said.

"I’m sure that as more people people start [drilling] wells in those places," he said, "there will have to be some clarification from the Legislature or the courts on that issue."