BALTIMORE (Map, News) - A mass of Styrofoam cups, plastic bottles and leaves churned slowly in the water in Canton, caught on its way from Baltimore-area storm drains to the Chesapeake Bay.

The garbage from streets and neighborhoods far from the Inner Harbor flows mostly unfiltered into the Chesapeake Bay — a fact few residents realize, according to a study sponsored by a coalition of watershed activist groups.

“People just don’t understand what storm water is and where it goes and what happens to it before it goes to the harbor,” said Mary Sloan Roby, executive director of the Herring Run Watershed Association, at a news conference Monday in Canton.

One out of six people knows storm water is not treated before re-entering the waterways, according to the study sponsored by the Stormwater Action Coalition, which represents 15 area watershed groups.

People more often think the trash in the harbor comes from tourists in paddle boats tossing bottles overboard, rather than the garbage cans up in Towson, said Steve Raabe, president of Opinion Works, which conducted the research.

Researchers directed four focus groups and 800 telephone interviews to evaluate public opinion about contaminated water in the Baltimore area. The study will allow activist groups to better tailor their message to encourage environmental conservation.

“This is an opportunity to engage people,” said Halle Van der Gaag, executive director of the Jones Falls Watershed Association.

The environmental groups now can better educate people on some “simple and tangible” moves they can make to help the health of the Bay, such as picking up after their pets and placing lids on garbage cans, Van der Gaag said.

One of the more surprising results of the survey was what Raabe called “visceral” responses to the dirty waters. Many respondents were embarrassed by the floating trash and hesitant to bring out-of-town guests to the harbor, Raabe said.

“This is a deep concern of people,” he said.

smichael@baltimoreexaminer.com