Triadelphia and Rocky Gorge Reservoirs, a pair of tree-lined 800-acre lakes in the close-in Maryland suburbs, appear almost certain to be closed to the public next year.

The lakes and 6,000 acres of woods around them have for decades been popular recreation areas for Washingtonians. About 200,000 fishermen, boaters, picnickners, equestrians and nature lovers used them last year, according to figures from the Washington Suburban Sanitary Commission, which owns the lakes and the surrounding land.

Last summer WSSC had financial troubles. The water and sewer agency asked for a 13 percent rate increase to cover the shortfall. Officals and customers in Prince George's and Montgomery countries objected vigorously, and the rate increase now appears certain to be deferred.

Robert McGarry, WSSC general manager, asked his staff leaders to draw up plans for reducing expenses to cover the shortfall, assuming the rate increase is not approved.

One of the recommendations was to shut down public boat ramps, picnic areas, fishing access, riding trails and all other public facilities. McGarry has given that and other belt-tightening measures his approval.

"The prospect of a rate increase doesn't look good," McGarry said yesterday. "We have been concerned about revenues not meeting expenses. Recreation comes up as a nonessential operation. Therefore we're going to eliminate it."

The fishing and boating season at the two lakes runs from March 15 to Dec. 15. Holders of $10 water use permits will get to use the lakes through the end of this season. But McGarry said the agency plans to issue no permits next year.

Picnicking is free at various sites on the lakes, but next year those facilities will be closed, he said. Horseback rides using bridle paths near Rocky Gorge have $10 permits that expire Dec. 30. They will be able to use the trails until then, but there will be no trail use after that either, McGarry said.

Word of the planned closures came as a shock to people who use the impoundments.

Mike Farnham grew up near Rocky Gorge and has fished there for 16 years.

"No," he said, "I don't think it's fair that the local people are going to get hurt by the financial woes of the WSSC. It's going to have a bad effect on people that like to fish and don't have the time or money to go to exotic places.

"Why should they close the lakes down? Isn't WSSC big enough that fishing and boating is just a tiny part of the operation?" he asked.

Jim Donald, a federal worker who is a consistent voice in support of close-in fishing impoundments, said it "sounds like a bluff to me. In government, when you're under pressure to cut back you always lay out the most popular programs, where you know you'll get public reaction to have it restored."

But WSSC officials said it was no bluff.

Art Brigham, public relations chief, said the agency feels it must cut expenses by at least $1 million. McGarry said something had to go. "Would they prefer that we not repair broken water mains?"

McGary said the recreation shut-down is only part of a wide-ranging belt-tightening that included elimination of 104 staff positions yesterday. Most affected employees were offered jobs in unfilled positions elsewhere in the agency, he said.

The general manager did say that if the requested 13 percent increase were approved, "I wouldn't make any of the cuts I've approved and I would budget next year for the operations that are being eliminated."

"Whether they would survive budget reviews next year I couldn't say," McGarry added.

Losing access to the lakes would affect more than a few diehard fishermen. Of the 200,000 visitors to the lakes and surrounding woods last year, many simply came to see the huge azalea garden at Triadelphia in bloom in the spring, others to enjoy the extensive bird life or to use the gentle waters for canoeing or boating.

There are bald eagles nesting at Rocky Gorge. Both Farnham and Clint Bowman, another regular there, have seen them on numerous occasions. Large flocks of migrating waterfowl use the lakes in the fall, and there are resident populations of herons, turkey vultures, hawks and kingfishers.

Both impoundments are surrounded by uninhabited forests. On weekdays in spring and fall, boaters could easily spend an afternoon of uninterrupted reverie on either lake.

"It really would be highly disturbing if they closed down," Donald said. "What are we supposed to do instead?"