Our floating wetlands was inspired by a project done on a polluted canal in Fuzhou, China. The 600 meter canal, named Baima, had extreme problems with odors and floating solids created by the daily influx of some 750,000 gallons of untreated domestic sewage. Rather then re-piping the sewage to a remote treatment plant, the city sought a more affordable way of treating the sewage within the canal itself. In 2002, John Todd Ecological Designs/Ocean Arks international designed and built a “Canal Restoration Device” that utilized a floating walkway planted with over 12,000 native plants as a way of biologically treating the waste.The plant root zones provided the biophysically diverse surface areas needed for biological treatment. An anoxic zone at the top of the canal allows for denitrification. A centrally located barge provided additional aeration, and helped circulate the water past biologically active zones. Two areas were designed to innoculate the system with bacteria known for their abilities to digest sludge and grease, as well as remove nitrogen. And it worked! You can read more about the results here: http://toddecological.com/files/case-studies/china.pdf
So the plants digest/recycle nutrients in the waste and a greenway is created in an area that was once an eyesore. The Canal Restorer not only is functional as a way of remediating sewage, but it also brings much needed attention to an environmentally disturbed area.
So we wanted to bring some of those same ideas to the boat. We wanted to create a floating wetland that ran its entire circumference. Not only could it function as a microhabitat for some of the fish, crabs, jelly fish and water birds that are already in the Gowanus, but it could also add biodiversity and aesthetics. And theoretically, the boat, at its core, would not only be a self sustaining structure, but additionally, it would help remediate the sewage strewn waters that it passed through.
Not only did our Canal Restorer (we call it a ‘floating wetlands’) have to act as a structure to hold the wetland plants, but it also had to act as a walkway (for maintenance/viewing) and a platform from which we could row the boat (the boat has no engine and was not mobile otherwise). Ben Cohen and Stephan Von Muelen enlisted to help build/design the physical structure (you can see some of the design ideas in an earlier post). There were lots of ideas, lots of plans, and a prototype. Here’s a picture of us down in Jaimaca Bay messing around to see how well the barrels we got actually floated. This one was a little too tippy for a Gowanus adventure, but we were able to glean a lot of information that was used in the final construction.
And here’s shots of the work party where we built the dock that the plants will be fastened to. Ours is a lot more ‘low-tech’ then the John Todd Canal Restorer in China. Its made from 100% salvaged materials and the plants are donated from two native plant nurseries: Pineland Native Plant Center in New Jersey and GreenBelt Native Plant Center in Staten Island. We are also planting phragmites, which will be collected from different sites in the area.