Other cities have launched projects to reclaim or expand wetlands, including Washington's plan to clean up the Anacostia River. What makes Baltimore's idea different, Schwartz said, is that the artificial wetlands would be made from trash, such as discarded plastic soda bottles, taken out of Baltimore's harbor and recycled to build the infrastructure.
Students affiliated with the Living Classrooms Foundation, a nonprofit educational group, will be enlisted to fabricate the islands, plant them with marsh hibiscus and other vegetation, and serve as docents to explain them to passersby once they are put in the water.
The Waterfront Partnership plans to create 200 square feet of floating wetlands this year that can be used as a demonstration project and monitored for effectiveness in improving the water quality. That's about a dozen islands measuring about 4 feet by 4 feet.
The partnership has sought approval from Maryland's Department of the Environment and the U. S. Army Corps of Engineers to put the floating islands in the harbor, and hopes to receive permission in the next few months. The proposed location is a zone of water just south of the World Trade Center, between Harborplace and the aquarium. That area was selected, Schwartz said, because it's in navigable water but off limits to boat traffic.
If the project is deemed a success, she said, the partnership would seek to add floating wetlands every year.
In a separate but related project, the National Aquarium plans to add another 200 square feet of floating wetlands in the inlet between Inner Harbor Piers 3 and 4, another area that boats don't enter because it's cut off by footbridges connecting the piers. That work will be commercially fabricated and is expected to be in place this summer, pending governmental approval and availability of funds.
Lee, of the watershed association, said floating wetlands have been used in lagoons and lakes before but have yet to prove themselves in tidal waters like the harbor. Even if they can withstand the elements, he said, the small floating wetlands that the partnership and aquarium plan to deploy won't make a huge dent in the nutrient pollution that feeds algae blooms in the harbor.
The only way to clean up the harbor, he said, is to halt the pollution from the watershed that drains into it, which reaches all the way into Baltimore County. "It's a good start, a visible start, but the hard work is going up the watershed, where the pollutants are coming from," he said.
Steinmeier, the waterkeeper, agrees that the floating wetlands alone won't clean up Baltimore's harbor.
"Do I think that installing floating wetlands in the harbor is going to solve our problem?" Steinmeier said. "Hell, no. We can't be treating the problem just at the harbor level. But that doesn't mean we can't also be treating it at the harbor level."
Baltimore Sun reporter Timothy B. Wheeler contributed to this article.