Irrigation shutdown to boost San Pedro flows

Nature lovers buy the farm

Photos by Benjie Sanders / Staff
The Nature Conservancy's Barbara Clark hops through the San Pedro River in one of the Southwest's best remaining strips of riparian habitat.

A heron finds the cool stream to its liking. The San Pedro region is home to 345 species of birds, according to the Nature Conservancy.

Conservancy pays millions for 2,156 acres

CASCABEL - With hopes of restoring year-round flows to 10 percent of the San Pedro River, the Nature Conservancy has bought a 2,156-acre farm that has pumped more than 1 billion gallons of ground water a year.

Photos by Benjie Sanders / Staff Dried-up mud may be evidence of overuse of San Pedro River water by farming. Cattle destroy young cottonwoods and other vegetation. Beyond the river's steep banks, lush forests demonstrate the effect that a water source has on desert land. Water pumping and damming have devastated many rivers in the Southwest.

The purchase of the Three Links Farm, about 15 miles north of Benson, is the conservancy's latest effort to protect Arizona's last remaining free-flowing river and one of the nation's hot spots for biodiversity.

Last April, with similar intentions, the nation's wealthiest environmental group bought a 528-acre alfalfa farm on the San Pedro near Mammoth, then shut off its wells to help the river.

The San Pedro, which begins in the mountains of Sonora, Mexico, and travels north 140 miles to the Gila River at Winkelman, is one of the Southwest's best remaining strips of riparian habitat. Its cottonwood and willow forests are host to 345 species of birds, nearly half of North America's avian fauna, according to the Nature Conservancy.

Terms of the deal were not disclosed by either party, but Nature Conservancy officials said the purchase price was in the millions of dollars.

The Three Links Farm lines about six miles of the San Pedro, but hydrology models predict that cutting its ground-water withdrawals will restore year-round flows to 14 miles of the river that now are dry for much of the year. Another six miles of the San Pedro should see enhanced flows.

"This is where we get the most ecological value for the money we're investing," said Dave Harris, the Nature Conservancy's Lower San Pedro program manager.

The Nature Conservancy is putting a conservation easement on the land that forbids most development and restricts water use to less than a tenth of what the farm used.

In the next few years, it plans to sell the farm in up to five pieces, ranging in size from 275 to 600 acres, with existing houses and corrals included.

"By selling the property to buyers who cannot build subdivisions along the river, we ensure the river will remain healthy and vital forever," said Pat Graham, director of the conservancy's Arizona chapter. "It also makes good business sense for us to recover our investment, so we can protect other special places."

The Bureau of Reclamation will also underwrite part of the purchase. The federal dam-building agency is required to mitigate its impact on aquatic habitat in Arizona, so it's buying a 1,420-acre conservation easement.

The Nature Conservancy doesn't expect to profit on the deal because the conservation easements will reduce the land's value. The group said it just wants to break even.

For the Dobson family, owner of the Three Links Farm, the sale comes with some regret.

"We've had it for 20 years. We built everything on that place; now it's gone," said Billy Resor, who works on the farm that his father-in-law owns. "It was a pretty hard decision to make, but it was the only way our family could go on.

"There's no money in farming," Resor said. "There isn't anyone in the whole United States making any money farming."

The Dobson family will still graze livestock on 130 square miles of ranch land around the Three Links Farm.

When the farm's pumps were running, irrigating several cuttings of alfalfa a year, the riverbed's cottonwood and willow seedlings struggled to take hold, Harris said. Vegetation had the rug pulled out from under it when the water table declined.

Cattle walking through the stream bed would trample the plants and munch on young cottonwoods.

"It's like candy to them," Harris said. "Removing these kinds of stresses on the system will turn this place into a jungle."

Thick cottonwood-willow forests are a rarity because so many of the arid West's waterways have been dammed, diverted or sucked dry by humans. The dense thickets are favored by the Southwestern willow flycatcher, an endangered bird, and the yellow-billed cuckoo, which may soon gain protection under the Endangered Species Act.

The Nature Conservancy also plans to restore about 1,000 acres on the farm to native, low-water-use grasslands. To do that, it will have to eliminate various invasive species that have taken root.

Harris said last year's purchase of the alfalfa farm near Mammoth already has cut the depth to ground water by about 10 feet, although the drought "hasn't helped us a bit."

University of Arizona hydrologist Thomas Maddock, an expert on the San Pedro whose research helped the Nature Conservancy pick which farms to buy, said those purchases, along with the reduced water demand at the San Manuel mine, should lead to more water visible in the San Pedro's northern section.

"It's certainly going to have a real positive effect on the river," he said.

Wells in the San Pedro basin intercept rainfall and snowmelt in between where it seeps into the ground, often at the base of mountains, and where it's released into the riverbed to become surface flows, Maddock said.

"As long as you don't have any big pumps centered between the recharge and the discharge, you're going to get water in the river," he said.

* Contact reporter Mitch Tobin at 573-4185 or mtobin@azstarnet.com.

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