Utah conservationists are taking aim at an Air Force plan to fly bombers low over the desert in a new training run - a route that would take them over some of the country's most spectacular wilderness study areas.

Up to two B-1B and two B-52 aircraft would use the new route daily. The route, called IR-323, would begin southwest of Ouray, Uintah County, head toward Green River, turn southwest toward Fremont, Wayne County, and Greenwich, Piute County.Eventually it would swing to the northwest, to the Utah Test and Training Range in Tooele County. The B-1B would fly as low as 600 feet at 620 miles per hour, while the B-52 would be only 400 feet above the terrain at speeds of 390 mph.

According to maps provided by the Air Force, the route apparently passes directly over several wilderness study areas, notably some in the San Rafael Swell west of Green River in southern Utah. The Swell is of such high quality - both for scenery and ecological values - that several organizations support its designation as a national park.

The 8.4-mile-wide flight corridor would reach to within about a mile of the boundary of Capitol Reef National Park.

George H. Gauger, chief of the Environmental Planning Division for the Strategic Air Command, based at Offutt Air Force Base, Neb., said in a letter to state officials that the route is proposed because it offers an approach from the east to the Test and Training Range.

An environmental assessment is being prepared, Gauger said. "We are particularly interested in identifying wildlife populations . . . and habitats and recreation land uses sensitive to aircraft overflights."

Bombers blasting along several hundred feet over the San Rafael River and Sid's Mountain areas "just isn't appropriate," said Gary Macfarlane, conservation director for the Utah Wilderness Association. One of the state's healthiest herds of bighorn sheep clamber through the rugged country of Sid's Mountain, he said.

In addition, he said, the flight corridor "goes right down Desolation Canyon," a famous river-running canyon and wilderness study area on the Green River.

"How many people run the river down Desolation Canyon? They're going to be bombarded literally and figuratively by these airplanes," Macfarlane said.

The flight path also goes over Fish Lake, a popular fishing spot, and other Bureau of Land Management wilderness study areas in the House Mountains.

"So it doesn't matter whether you're an outdoor recreationist or livestock permittee or what, these things are going to have an effect on your use of the public lands," he said. "It really calls into question who owns and controls our public lands."

Ken Rait, issues coordinator for the Southern Utah Wilderness Alliance, said the flight route would distract from the wilderness qualities of the land it crosses.

"I think there are probably alternative sites where they could do this type of activity," he said.

"Certainly we're going to see tremendous impacts upon sensitive populations of species such as bighorn sheep." Bighorns are particularly jittery if loud noises disturb them during the spring lambing period.

In addition, Rait said, the "general spirit of wilderness" would be damaged by low-level bomber flights. He called for the Air Force to prepare a full-blown environmental impact statement on the plans.

"We're going to see if we can work with them in terms of alternative flight routes. We'll just have to see where it goes from there."

"The Strategic Air Command does not need this route," said Steve Erickson, an activist with the military watchdog group Downwinders.

"They have thousands and thousands of miles of low-level military training routes throughout the United States, primarily in the West. They're still caught up in a mentality that we must be training actively and excessively for nuclear war with the Soviet Union."

With a route that is 200 miles long and 8 miles wide, the Air Force would blanket 1,600 square miles of Utah with its low-level flights from IR-323 alone, he said.

Erickson too said the Air Force should prepare an environmental impact statement, instead of the less specific environmental assessment now in the works. "It's going to have a significant impact. It's a major federal action," he said.

Lawson LeGate, the Sierra Club's southwest regional representative, said he has been buzzed by a low-flying plane in another state.

"It can be very surprising when they fly at low level because you can't hear them coming, and then they're right on you all of a sudden . . . If it happens on a regular basis, I think that could really affect that wild-country experience so many people are seeking."

In addition to bighorn sheep in the desert regions, elk could be spooked in higher country, such as the Book Cliffs, he said.

"It's high time we take a look at the cumulative effects of all of the military operations areas, because, gosh, they seem to be proliferating over the West," LeGate said.

"It's getting harder and harder to find any place where you can escape this sort of activity."