Bill Manda, a 51-year-old disabled Metro worker from Silver Spring, stood on the sandy banks of Triadelphia Lake in Upper Montgomery County recently and peeped under a big wet rock.

A smile cracked across his craggy face. His arm quickly poised to strike at a small creature racing for darkness under the stone.

Swooosshh!

Manda put a strangle hold on a frantically wiggling crayfish.

"Looka here, Winnie, see what I got," yelled Manda to his wife as he plunked the struggling creature into a bucket of muddy water teeming with life. Both Manda and his wife peered into the bucket and exploded with laughter as the crayfish crawled through a mass of tiny creatures sloshing in the water.

It was a typical Sunday at the lake for Manda, who said he comes at least once a week to Brighton Dam (Triadelphia Lake) to find new specimens for his home aquarium.

Manda, a lanky, silver-haired man, is like thousands of other area residents, who find peace and quiet at the Upper Montgomery County reservoir.

Brighton Dam, built in 1943, is apparently more appealing then other local spots, according to Washington Suburban Sanitary Commission officials, because it is reasonably close to town, but has the relaxing benefits of its rural setting.

WSSC officials say the five-and-a-half-mile long lake, which feeds the T. Howard Duckett Dam in Laurel and ultimately provides drinking water for residents of Prince George's County, is also the home of the largest azalea garden in Maryland.

Paul Hancock, watershed supervisor for the area, who has worked at Brighton Dam for more than 25 years, said WSSC will have the results of a survey in December that will indicate the number of people who visit the dam each year.

The 49-year-old watershed supervisor said that WSSC has been able to control the water quality of the reservoir by prohibiting swimming and the use of gas-powered motorboats.

Manda once owned a boat, bought with a friend who he had met at the lake severl years ago. His friend recently left the area, however, so now he spends his time exploring and fishing from the banks of the lake.

"I scrounge a lot," said Manda, wiping brown mud off his shoes. He has found more than 1,000 sinkers and 300 lures in the murky bottom of the lake during his explorations, he said.

"All I do is clean them up and fish with them . . . I've caught some of the largest bass with them."

Manda's wife, who usually sits in the car during her husband's adventures, said she is "just happy Bill has a good time."

According to Manda, he knows the best fishing spots on the lake, because he waited until the water level dropped last summer during the drought and took pictures of the lake bottom.

Trenton Wagenor, of Columbia, and his brother Thomas, who was visiting from Texas recently, both discovered they didn't know the best fishing spots. The two fishermen just shook their heads as small mouth bass ignored them and leaped out of the sunlit water nearby.

"Those fish are just having fun with us. They don't want our bait. They just want to let us know they are out there," said Trenton. He added, however that when his luck is better, small mouth bass, catfish, crappie and other "good eatin' fish" can be caught at the lake.

But fishing wasn't all that Trenton or his brother had come for according to the avid outdoorsman. He said he and his brother were looking for peace, quiet and relaxation. "This is just a place located between the shopping malls and highways," said Trenton.

In the past, some visitors to the dam had been troubled by rowdy teenagers, a problem which now has been corrected, according to WSSC officials.

Drunken and rowdy teenagers had caused problems for families who brought their picnics to the lake, said Lloyd. Abbott, a security patrol officer at the dam. As a result, WSSC closed the Brighton Dam picnic area until the school year ended, he said. Since the grounds opened in June, the security guards have stepped up patrols of the area, Abbott said.

Dan Matys, 27, who is stationed at Ft. Meade, recently brought his family to the picnic grounds near the dam. "I love it here. It is not far and it is serene and quite."

Matys said he chose a Monday to visit the lush green picnic grounds because, "it's impossible to find a place to picnic on the weekends."

According to 19-year-old Wally Golden, who came to Brighton Dam to pass the day with friends, it has always been "just a place to relax."

At the Green's Bridge boat mooring ramp, Doug Smith, a local high school teacher who was launching a boat, said there were "no hassels on the lake . . . and its quiet because they only allow electric boat engines."

As Smith spoke, boaters lined up at the ramp to launch their boats into the calm waters of the lake. As the temperature rose and Smith wiped perspiration from his forehead, he added, "The only drawback here is that you can't swim in the water."