The controversy simmers as a report released in October by a group of Harvard-led scientists found that nitrogen levels were too high in about half of the country’s national parks undefined in large part because of ammonia emitted into the air by agricultural operations, which can deprive fish of oxygen or drive out some vegetation in an ecosystem. This phenomenon is expected to worsen in coming decades as corporate farming increases, according to the report.

In response to the uproar here, the state has temporarily imposed more stringent notification requirements for future CAFO applicants, acknowledging that many crucial players, including the superintendent of the river and the director of the state agency that permitted the operation, knew nothing about the project until after it had been approved.

Gov. Mike Beebe of Arkansas, a Democrat, has allocated more than $340,000 to test and monitor the water quality in the watershed. Both of Arkansas’ United States senators undefined John Boozman, a Republican, and Mark Pryor, a Democrat undefined have said they were concerned about the location of the farm, and supported close monitoring.

Environmental groups have filed a federal lawsuit against the Farm Service Agency and the Small Business Administration to try to block $3.4 million in loan guarantees for the farm, arguing that the agencies had not properly considered its environmental impact.

“I was just sick over it undefined I just couldn’t believe it,” said Jewell Fowler, 87, who found out about the hog farm after it had been approved, through a notice in a local newspaper. Born in Mount Judea, Ms. Fowler has lived for the past four decades in a wooden cabin on the banks of the Big Creek, one of the main tributaries to the Buffalo River: a quiet oasis where the trees emit a sugary scent and water laps over rocks in a soothing whir.

“I’m just afraid of the stink, maybe contamination, make people sick,” Ms. Fowler said.

But the farm in Mount Judea has received considerable support, not least from some residents who live close by. Many see it as an economic bright spot in Newton County, which has high poverty.

On a recent chilly morning, a scent evoking a mucky lagoon curled over the hill where Glen Ricketts lives. He cracked a smile.

“You smell it,” he said.

From Mr. Ricketts’s property, looking down a valley in the distance, a pair of white triangular roofs pop up like fins amid a sea of trees. They are the large barns that house the pigs.

“Reason why it don’t bother us, we’re just hillbillies,” said Mr. Ricketts, 55, who is related by marriage to some of the farm’s owners. “When you’re raised up around a hog, it don’t bother you.”

Charles Campbell, 77, has permitted the farm’s owners to spray some of the manure on his land.

“I don’t think that it would pollute the river at all,” he said. “I’ve lived in this country for, well, all my life, and cattle and hogs has been raised up and down the creek here, and to me it ain’t bothered nothing so far.”This, however, is unlike any other hog operation in the area. With just over 2,500 sows undefined producing thousands of piglets undefined C&H has more of them than all of the other hog farms now operating in the Buffalo River watershed combined.

The farm, its operators say, produces nearly 1.5 million gallons of hog manure a year if it runs at capacity. The waste is being stored in large lagoons and sprayed as fertilizer on nearby fields, some of them close to the Big Creek. Ten of the 17 fields that will receive fertilizer will have dangerously high phosphorous levels within a year, Kevin Cheri, the superintendent of the Buffalo River for the National Park Service, wrote in a letter to the Farm Service Agency.

Environmentalists also worry that rain could cause the manure to run off into streams and creeks, especially because of the type of topography in the area. Known as karst, it is essentially a permeable limestone rock with many cracks and caves beneath the surface that water flows through quickly and easily, potentially allowing contaminants from the manure to seep into the ground and settle throughout the watershed. Some business owners worry that pollution would devastate tourism. The river attracts more than a million visitors each year for hiking, horseback riding and canoeing.

“There is a probably greater than 95 percent chance that we are going to see impacts of degraded water quality and major environmental degradation,” said John Van Brahana, a recently retired hydrogeologist from the University of Arkansas who has conducted tests in the area.

Supporters of the farm argue that unlike the small operations that have been common throughout the watershed, this one uses more environmentally friendly technology to prevent pollution. For one thing, the lagoons holding the waste are larger than required and use a clay liner that will prevent leakage, supporters have said. (Dr. Brahana said he believed the type of clay the operation was using would leak.)

C&H was the first undefined and still the only undefined hog farm in the state approved through a new general permit that officials created for CAFOs to comply with federal rules. That permit did not require the strict procedures for notifying neighbors required for other agricultural permits in the state.

Even some of the farm’s staunchest opponents said its owners were good, hardworking people looking to make a living, but they were critical of how they went about establishing the operation.

Teresa Marks, the director of the Arkansas Department of Environmental Quality, said that while