Charles Gougeon held in his hand a wriggling brown trout, just caught from the sun-dappled creek nearby.

Gougeon was standing under a canopy of trees in Colesville, between New Hampshire Avenue and Columbia Pike. "Take a good look around," Gougeon, a fisheries biologist for the state Department of Natural Resources, told reporters last week. "We don't know how long they'll be here."

Gougeon's wading boots were planted on the muddy banks of the Good Hope tributary to Paint Branch, a tributary of the Anacostia River. The Anacostia, once a rich fishery, is now so clogged and dirty that it is considered a triumph to find a place where the fussy trout will live and breed.

The Anacostia is the subject of a multimillion-dollar cleanup effort now nearing the end of its second year, with help from the federal government, Maryland, the District, and Prince George's and Montgomery counties. The aim is to turn the river around by the end of the century.

Private groups also are becoming involved in the effort. A conservation group called START, for Stop Trashing the Anacostia River Today, announced a campaign in April to help clean up the river and to create a "continuous grand river park" along its banks from the District into Prince George's and Montgomery counties.

Unlike the Potomac, which benefited enormously from a single action -- improvements to the Blue Plains sewage plant -- advocates say the Anacostia will require the sum of many smaller actions to reverse years of pollution by a variety of sources, including road-building, subdivision construction, sand and gravel mining and sewage. The biggest problem is sediment choking the water. Many of the Anacostia cleanup projects are unglamorous stormwater filters, litter pickups or marsh plantings to restore conditions that existed decades ago.

The results are mixed so far. Advocates are encouraged that government officials have not balked at paying their share, and that plans are going forward for 40 new initiatives for the fiscal year beginning Oct. 1. Several major efforts were completed during the past year, including an $800,000 project to contain and filter stormwater for a major portion of Wheaton.

But in the Good Hope Tributary, the trout are barely hanging on. The number of young caught in the tributary's sampling station rose slightly in 1989, but the number of adults dropped, lowering reproduction prospects.

The reasons are varied: Sediment and sand from a large storm or sloppy construction can choke the creek or bury incubating eggs. Weak stream banks can erode, dumping in more dirt. If nearby trees are taken down, more sun falls on the water, making it warmer than trout can tolerate. Trout do not usually breed until their third year, so a big storm one spring can set back population growth for four years.

If the disputed $280 million Intercounty Connector is built between Route 1 in Prince George's County and Interstate 270 in Montgomery County, using the route proposed by Maryland highway officials, it would remove vegetation less than a mile from Gougeon's creek, and "we'll lose that tributary," he said.

Federal officials, however, want the route moved farther north because the planned route would cross wetlands, floodplain, woodland and park.

"You keep getting the argument: Is it worth it for a few lousy fish? It's a symbol," said Bob Schueler of Silver Spring, who is active in the campaign by Trout Unlimited to block the state's proposed route. "It's a question of whether you can have subdivision development and environmental quality."

Across the county line, in Beltsville, Prince George's and state officials cracked the dirt with gold shovels last week to begin construction of a $70,000 project to improve water quality in Indian Creek, the Anacostia's dirtiest tributary.

The county will expand an existing flood control dam. By holding onto storm water for 12 hours or so, the project also will prevent water from engulfing the creek all at once.

Ultimately, County Executive Parris Glendening said, the project will help clean the Chesapeake Bay.

"Very few people understand that way back up here, it's going to flow to Berwyn Heights to the Anacostia, to the Potomac, and it's going to end up in the bay," he said.