District officials last week charged that the sewage treatment plant now under construction near Rockville - which will dump three million gallons of treated sewage a day into Rock Creek - was approved in violation of federal law and will significantly degrade the creek. The city has designated Rock Creek as a future fishing and swimming stream and as a possible future water supply for the nation's capital.

Speaking at 3 1/2 hour public hearing, held by the U.S. Army Corps of Engineers last Thursday night in Rockville, John D. Brink, chief of the District's Bureau of Air and Water Quality, said the city is concerned that in summer months more than half of the water in Rock Creek would be treated sewage effluent if the treatment plant is allowed to dump into the creek. The average summertime flow of Rock Creek is now 2.4 million gallons a day.

Reading a statement of Herbert L. Tucker, director of the District's Department of Environmental Services, Brink accused Maryland and Montgomergy County of failing to give the city proper notice, which must be given to affected states (and the District) under federal water pollution laws, and a chance to respond in writting before they approved the sewage plant last year.

The city also contents that federal law prohibits the lessening of water quality in waters considered an outstanding natural resource, such as streams in national and state parks, a law that Marlyland "admittedly did not review" when it approved the sewage plant, Brink said. Rock Creek is such a stream, the city argues, since the federal government created one of the nation's first federal parks around it in 1890 and the National Park Service has been pledged for decades to improving and protecting the stream.

Park Service spokesman James Redmond, superintendent of Rock Creek Park, told the 80 people attending the hearing that the Park Service is dedicated to making Rock Creek "a model stream for a metropolitan area" and is concerned that the Corps of Engineers "could be setting a precedent" if it permits the plant to be constructed without considering the cumulative impact of this and other treatment plants on Rock Creek.

The navy is now proposing to build a 70,000 gallon a day treatment plant on Stoney Creek, a small tributary of Rock Creek at the National Naval Medical Center in Bethesda just above the District line. But the Corps of Engineers is not reviewing it because its policy is not to review discharges into creeks with flows less than 5 cubic feet per second (CFS). The navy has estimated Stoney Creek's flow at 5-10 CFS but the corps says the flow is under 5 CFS.

County and state officials, and an attorney representing the private developers who are building the $9 million sewage plant, said that they complied with all notification laws in approving the plant and contend that Rock Creek is not a "high quality" stream protected by federal law.

They also disputed the Corps of Engineers' right to review the environmental effects of the sewage plant. According to David G. Sobers, director of Montgomery County's Office of Environmental Planning, they contend that the "hearing only pertains to the effect of that small structure and small pipe" that will actually be built on the edge of Rock Creek and not to the effect of the three million gallons of treated sewage a day that will come out of the pipe.

Sobers said that the issue of water quality is the responsibility of state water resource department officials who also act on behalf of the Environmental Protection Agency, State officials have determined the sewage effluent will not have an adverse effect on Rock Creek, he said.

While declining to admit that the Corps of Engineers legally can consider the issue of water quality, Sobers nonetheless said he wanted to reassure citizens that "We've reviewed the effects of the discharge and are satisfied with the effects both quantitatively and qualitatively."

Environmental and civic groups speaking at the hearing were not as confident Scott Allen, spokesman for the Sierra Club, said, "We are fundamentally opposed to the discharged of wastewater into small streams . . . especially when other allternatives exist" such as discharging into large rivers like the Potomac or irrigating (spraying) the treated effluent on farmland.

"That the plant meets state and EpA pollution standards is not very reassuring to me," Allen said, nothing the extensive pollution in U.S. rivers and the large number of viruses and pollutants that cannot even be traced - let alone removed - from water.

David Burwell, an attorney representing the National and Maryland Wildlife Federations, said he was concerned about "the cumulative effect" of the two sewage plants that propose to dump effluent into Rock Creek. He said the effluent will have "a dramatic effect on the District of Columbia" and that the corps should hold public hearings in the city as well as do a comprehensive environmental impact statement on the sewage plant. The Corps of Engineers is now in the process of preparing a limited environmental impact assessment.

Several civic groups and residents also expressed concerns about the sewage plant and its effluent, including Jennie Forehand, consumer representative of the Montgomery County Health Services Planning Board. She asked for a full environmental review because the review by state and county officials considered the effluent's effect on plants, fish . . . and even squirrels . . . but not on people" who live near Rock Creek.

The Corps of Engineers is keeping the hearing record open until Dec. 1 for anyone wishing to have a written statement considered before the corps decides whether to grant a permit for the sewage plant to dump in Rock Creek. Letters should be sent to the Corps of Engineers at P.O. Box 1715, Baltimore, Md. 21203.