CARLSBAD, N.M. » Just after the local water board announced this month that its farmers would get only one-tenth of their normal water allotment this year, Ronnie Walterscheid, 53, stood up and called on his elected representatives to declare a water war on their upstream neighbors.

"It’s always been about us giving up," Walterscheid said, to nods. "I say we push back hard right now."

The drought-fueled anger of southeastern New Mexico’s farmers and ranchers is boiling, and there is nowhere near enough water in the desiccated Pecos River to cool it down. Roswell, about 75 miles to the north, has somewhat more water available and so is the focus of intense resentment here. Walterscheid and others believe that Roswell’s artesian wells reduce Carlsbad’s surface water.

For decades, the regional status quo meant the northerners pumped groundwater and the southerners piped surface water. Now, amid the worst drought on record, some in Carlsbad say they must upend the status quo to survive. They want to make what is known as a priority call on the Pecos River.

A priority call, an exceedingly rare maneuver, is the nuclear option in the world of water. Such a call would try to force the state to return to what had been the basic principle of water distribution in the West: The lands whose owners were the first users of the water — in most cases farmland — get first call on it in times of scarcity. Big industries can be losers; small farmers winners.

The threat of such a move reflects the political impact of the droughts that are becoming the new normal in the West.

"A call on the river is a call for a shakeout," explained Daniel McCool, a University of Utah political scientist and author of "River Republic: The Fall and Rise of America’s Rivers."

"It’s not going to be farmers versus environmentalists or liberals versus conservatives," he said. "It’s going to be the people who have water versus the people who don’t." And, he said, the have-nots will outnumber the haves.

Dudley Jones, the manager for the Carlsbad Irrigation District, said that water law and allocation practice have long diverged. "We have it in the state constitution: First in time, first in right. But that’s not how it’s practiced." In New Mexico’s political pecking order, his alfalfa farmers, despite senior priority rights dating back 100 years, have little clout. The state water authorities, he said, "are not going to cut out the city."

"They’re not going to cut out the dairy industry," he added. "They’re not going to cut off the oil and gas industry, because that’s economic development. So we’re left with a dilemma — the New Mexico water dilemma."

A priority call, said McCool, "will glaringly demonstrate how unfair, how anachronistic the whole water law edifice is."

He added, "The all-or-nothing dynamic of prior appropriation instantly sets up conflict. I get all of mine and you get nothing."

Despite the support Walterscheid got from two of the Carlsbad Irrigation District’s five members, however, the March 12 meeting produced not a priority call, but an ultimatum: The Legislature should give Carlsbad $2.5 million to tide it over, or the water district will make the call and start a traumatic legal and scientific battle.

The prior appropriation system on the Pecos has its beginnings in the late 19th century. Its waters flow about 925 miles from the Sangre de Cristo Mountains in northern New Mexico, ending up in the Rio Grande in Texas. It has been a focus of conflict. Texas, saying upstream users were taking its share, won a 1987 Supreme Court ruling guaranteeing deliveries under the Pecos River Compact.

After the ruling, which was signed by the feuding water districts, Roswell took steps to conserve water, including putting meters on wells, limiting withdrawals, allowing five-year averaging of water use and buying out some farmers. At the Pecos Valley Artesian Conservancy District in Roswell, officials take pride in this foresight and maintain that they are not cheating Carlsbad.

"If we turned off every one of our pumps today, they wouldn’t see any more water," said Aron Balok, the district’s manager. Nonetheless, the bounty of the Roswell-Artesia aquifer, which has produced a robust economy, including abundant dairies, an oil refinery and the West’s biggest mozzarella plant, gives rise to "just plain jealousy" in Carlsbad, he said.

"If the priority call were executed today," Balok said, "the refinery would shut down. The cheese plant would shut down. The dairies would shut down. To what end? It wouldn’t make water appear." The agreement made to settle the dispute with Texas was supposed to stop such brinkmanship. But, he said, "Nobody ever foresaw it being this dry for this long."

How dry is it? In 2012, parts of the riverbed were dry for 77 days, said Mike Hamman, the area manager for the federal Bureau of Reclamation in Albuquerque. In 2011, with the drought sending feed prices up, the Clovis Livestock auction house, the region’s biggest, sold 144,000 head of cattle, 20 percent above average. "Some herds have sold out," said the president, Charlie Rogers. Most ranchers "have reduced back from 70 percent down to 25 percent." Hay, he said, costs too much.

Higher prices, however, did not offset the losses that hay farmers like Mark Weems and Billy Grandi in Carlsbad suffered when they could not water their fields. Weems said he had to sell 22 acres to make payments on his farm and equipment. The buyer: an oil-related company that wanted the water rights.

As for Brantley Lake, the nearest reservoir, "Two months ago it looked like you could drive a four-wheeler across it," Weems said. Grandi added, "If the drought continues, a lot of farmers will just have to sell out."

Hamman understands that fear. "If indeed we are moving into a new climate regime that is going to limit the ability to continue the status quo," he said "we may have to do something different — reallocate the system, or make adjustments to existing settlements."

The climate and the economy on which existing compacts were based may have fundamentally changed. In the West, "the 1 percent of the economy that is farming takes close to 80 percent of the water," McCool said. The Pecos feud, he said, is a prelude to wars on rivers like the Colorado, which provides water to more than 20 million people. A recent federal study showed that the Colorado will not have enough water to satisfy existing claims.

In a shakeout, farmers cannot prevail, McCool argued. "Let’s see, we could dry up some hay farms or we could dry up Las Vegas. Which one is it going to be? It’s going to be the new economy of the West with the focus on recreation and tourism and hunting."

"There will be farming ghost towns," he said.

© 2013 The New York Times Company