More than 50 modern-day expeditionaries took off into uncharted environmental territory around Herring Bay in southern Anne Arundel County yesterday, hiking along neglected shorelines, paddling up shallow waterways in canoes, even flying overhead in an airplane.

The goal was to compile the first comprehensive study of threats to the picturesque tributary of the Chesapeake Bay that has made the waterfront town of Deale increasingly popular with refugees from city life.

The volunteers found gasoline traces in the water in the Town Point marina, trash in otherwise scenic Tracey's Creek, even a collection of iron barges abandoned at the end of an unnamed inlet.

The group is part of a growing movement by the state and environmental groups to enlist residents in the campaign to clean up the Chesapeake Bay.

"We say you're not going to clean up the bay unless you start in your back yard," said Terri Lehr, a project manager for Save Our Streams, the nonprofit organization that sponsored the survey in conjunction with activists, businesses and the state Department of Natural Resources.

"We want people to recognize that seemingly small things like over-fertilizing lawns, not picking up after a pet, using too many pesticides, using fertilizer as a de-icer or dumping things into storm drains have a big impact," said Sean McGuire, a Department of Natural Resources official who coordinated state support for the event.

In 1995, the state created three Tributary Strategy Teams--for the southwestern shore of the bay, the lower Patuxent River and the lower Potomac River--to develop plans to reduce phosphorus and nutrient pollution in the bay by 40 percent from their 1985 levels.

"By 2000, we will meet our phosphorus level and we will be very close to meeting the nitrogen level," McGuire said. "But as population grows, the only way to cap those nutrient levels is to get people to adopt the best practices in the watershed where they live. That's where education comes in."

The day began with a short training session at Deale Elementary School, where Lehr gave a presentation about what the volunteers should look for: exposed sewer lines, unusual stream conditions and barriers to fish migration. Armed with a 13-page checklist to record their findings, the volunteers scattered to their assigned territories.

Doug and Terri Sisk, owners of an auto body shop in Owings, hiked through the thicket along an inlet of Herring Bay called Rockhold Creek with three of their children. As daughter B.J., 20, took notes about a rusting oil drum sinking in the mud amid ever-present plastic bottles, Sisk explained why he insisted that his younger children, Doug, 11, and Anna, 8, also come along.

"We live on the water in Holland Point," he said. "It is just so beautiful that we have to protect it, to give back to the community. I want them to learn that when they get older, they've got to give back, too."

Meanwhile, Allen Flinchum, owner of a boat yard in Severna Park, rode in a small powerboat with his daughter Evann, 12, taking notes on the abandoned boats along the shoreline that may be leaking oil, fuel and battery acid into the bay.

"I run a clean place, but I like to stay ahead," he said. "I want to know everything that can cause a problem."

The volunteers' findings will be compiled in a report to be released in December, Lehr said.

"If a Boy Scout troop wants to do a cleanup, the people here will be able to direct them to the right place," she said. "If there's something that only the county or the state can do, they can be alerted."

CAPTION: Terri Sisk and daughter B.J. use a survey form to note the water conditions at Town Point marina as part of the effort to document problems in Herring Bay.

CAPTION: Rockhold Creek passes under Route 258 and through farmland toward the Chesapeake. Nutrients from farms are considered a major hazard for the bay.