The majestic site 180 miles northwest of Washington where a small creek rushes down a slope of jutting rocks to join one of America's most beautiful white-water rivers is the focus of a new environmental battle in which both sides say they have nature's best interests at heart.

Near where Deep Creek joins the Youghiogheny River, one of Maryland's natural wonders, the residents of Garrett County are planning to build a sewage treatment plant whose discharge would empty into the creek and ultimately into the river.

Residents of the communities of McHenry and Thayerville, a few miles from the river say the treatment plant is critical to develop their areas and to prevent pollution of their most vital natural resource, Deep Creek Lake.

Environmentalists, pouring in from the Washington area and Baltimore, assert that the plant's discharge may be lethal to the trout that inhabit the Youghiogheny.

"The locals are willing to risk the river to save their lake," says a Baltimore environmentalist.

That is parried by a local resident who says those challenging the plant "must accept the onus of jeopardizing the lake," if they continue to fight against construction of the treatment plant.

"This is not a battle pitting good guys against bad guys . . . Not the forces of crass commercialism against lovers of the environment," said Garrett County Administrator Marshall Rickert. "We want to guarantee that Deep Creek Lake is not polluted, and we do not believe that the treatment plant discharge will harm the fish in the Youghiogheny."

The sprawling like with its 69 miles of shoreline can draw as many as 15,000 visitors on a summer holiday weekend to a community with a year-round population of about 1,000. Motels, restaurants, and resorts dot its shores and many residents here depend on the lake for their livelihoods.

"We don't need anybody to come up here and tell us how to run our county," said Celeste Lascaris, who operates the Silver Tree Inn, a restaurant on the lush, forested shores of Deep Creek Lake.

Lascaris said the community needs the treatment plant "desperately or our lake will be polluted. We have people up here who watch out for everything in the environment and they would do nothing to hurt the lake or the river."

The treatment plant skirmish is not the first time "The Yock, as the river is called, has brought environmental controversy to the area in this westernmost finger of Maryland.

Two years ago, when the state passed stringent regulations to limit development along a 22-mile corridor of the wild river, land owners along the Yock exploded, calling the regulations "communistic."

Since then they have denied the public access to the river, although before the regulations were passed, fishermen and others who wanted to use the river had been welcome on their land.

Now "no trespassing" signs can be seen on the property along the river, and when someone ignores the signs, "They get run off in a hurry," according to land owner Burnice Thomas.

The state's regulations ban any changes in the existing buildings or landscape along the river - even the painting of a house or barn - without permission from state officials.

The land owners' response to the regulations?

"We ignore 'em," said retired farmer William Martin Friend.

The land owners along the Yock have stayed out of the current controversy over the sewage treatment plant, which would not serve their area.

Other local residents who are well aware of the previous fight between the landowners and state officials view this new controversy as just another example of outsiders trying to dictate something that is none of their business.

Most residents in the McHenry Thayerville area use septic tanks to dispose of sewage. The sewage flows to the tanks, is treated there and seeps into drain fields on the property. Some of these fields have become overworked during the 50 years since the community developed. When this happens the sewage "begins to percolate to the surface of the fields" and rain water could make it run into the lake, according to county planning director Tim Dugan.

Dugan not only fears this possible pollution of the lake, but also said the new sewage plant is essential for community development as the county has planned it.

The sewage treatment plant first was proposed in 1967, but various delays - changes in federal guidelines, problems in funding engineering studies and finally, last year, the challenge from an environmental group called Trout Unlimited - have put off construction and raised the system's cost to $10 million according to current estimates.

Recently, whenTrout Unlimited's lawyer, Monroe Mizel, made it clear that his organization would go to court to prevent a threat to The Yock, it was the last straw for many anxious residents.

The Trout Unlimited group maintains that it is not opposed to the construction of the plant, but only to the use of chlorine to kill bacteria in the sewage. The state has said it will permit a level of two parts per million of chlorine in the water that leaves the treatment plant.

This, says Trout Unlimited leader, James Gracie, would be lethal to trout.

One county official said that amounts of chlorine below two parts per million cannot be measured. He says that the level of chlorine in discharges leaving the plant will actually be below the state-mandated level, although there will be no way measure this. This county also says that as the discharge mixes with water in Deep Creek, it will further reduce the chlorine content.

Gracie says that there is not enough water in the half-mile run from the plant to the entrance of the Yock to do the job.

Although charges and counter-charges continue to fly, the the two sides came to a tentative and precarious agreement Friday to seek a sophisticated study of what the discharge will do to the river's fish and plant life.

Gracie and his group said last week that they would drop their opposition if better monitoring systems to detect levels of chlorine are required in the plant and if the special environmental study is done.

The study is dependent upon obtaining federal or state funds.

If would provide much needed information to prevent environmental disasters as sewage treatment plants are built on natural waters all across the country, according to Gracie.

Another Trout unlimited member, lawyer Barton Walker, views the county's agreement to seek funds for the study as a "big win" for the environmentalists.

Many of the local residents of McHenry and Thayerville are skeptical of whether money will be available for the study. Despite the hint of compromise in the air, the residents anger toward the environmentalists, who they call "outsiders," still is very evident.

Other residents said they are tired "of the fuss and the delays."

Gary Yoder, who has studied the ecology of Deep Creek Lake for the state, said that "People have to realize there are no absolute, perfect solutions to some problems.

"The fishermen and county residents are going to have to get together and find the least dangerous method of sewage treatment that will do the most possible good. And they'll have to face the fact there might be some risk involved."