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Dave Brigante

Ingenious Materials and Design Create
Floating Islands
at The Oregon Garden

by Dave Brigante, Oregon USA
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This past summer I experienced an unusual and exciting working day for nature. I was invited to participate in the planting and launching of three different sized BioHaven floating islands at The Oregon Garden. Designed for overall water quality enhancement, these islands amazingly can remove unwanted contaminants such as fertilizers, nitrates, phosphates, ammonia, heavy metals and organic waste from the water. The hands-on demonstration project was a collaboration between Garden SPROut Director Renee Stoops and Sean Dempsey of Floating Islands West (a licensee of California and Oregon). Floating Island International, Shepherd, Montana USA, is the original developer of the floating island technology.

On an overcast day at the Oregon Garden, Silverton, an inspired group consisting of Renee, Sean, a wine grape grower, a landscaper and I (aquatic plant grower) gathered for the project. We were also visited by a couple of other interested parties, a water treatment plant supervisor and someone who processes fruit products. It was a diverse group to say the least, which I believe had a focused concern about something that would not only improve water quality but would also create something of beauty while invigorating the resident wildlife. 

The floating islands themselves are made of fibers created primarily from recycled plastic water bottles, giving us even more motivation to always recycle those plastic bottles, as if we needed any more incentive. The fibers, once bonded together, form a massive surface area that attracts millions of contaminate-removing microbes, literally forming a mini-concentrated-wetland that can be as efficient as natural wetlands. As the pollutants are successfully eradicated and water quality improves, the islands’ versatility is apparent. They can also become nesting areas for waterfowl, food suppliers for insects and reptiles, and provide excellent protective cover for fish.

In looking back at this experience, it was enjoyable realizing that we built something self-sustaining with a positive impact on local environment. Once we were able to get over all of our feel-good moments during the preliminary learning process, we went about the task of planting and ultimately launching our living and breathing islands.


Each island was about 8" (20cm) thick, as four 2" (5cm) layers were pegged together using a polyurethane foam, which also created an amazing amount of buoyancy. After we carried our mattress like barges down to the water’s edge, Sean explained the step by step procedure involved in getting one of these islands planted. Previously 2" (5cm) diameter by 4" (10cm) deep holes had been drilled into the top two layers approximately 6” (15cm) apart across the entire surface area, providing planting pockets for our mostly northwest native aquatic plants. Before we started on the planting, we spread an organic compost over the tops of the islands and filled in the holes to give the plants a good start once they were situated.

The next step was to cover the soil by pinning down a woven mesh jute material to help keep the soil and plants stable. To be able to actually plant into each of the planting holes we went back to each location and cut a couple of crossing slits through the mesh material allowing for the plants to be placed precisely where we wanted them. If it happened that a root mass was a bit too large for the openings, the holes could be modified by cutting larger openings into the top two layers by using a serrated knife. After completing our final preparation our planting party could begin. 


We had 4" (10cm) pots to divide, crates of bare root individual plants and 2" (5cm) plugs to either split or plant directly. The assortment was a mix of arrowheads (Saggitaria sp.), rushes (Scirpus sp.), sedges (Carex sp), marsh marigolds (Caltha palustris), Lobelia (Lobelia cardinalis), stream bank dogwoods (Cornus sericea), umbrella plants (Darmera peltaphyllum), and even some native spatterdock (Nuphar polysephalum). We tried to stay cognizant of the fact that we really didn't want to use any plants that might take over the whole island or even spread into the water to someday become a nuisance.

Our design was as simple as putting the tallest specimens in the central areas and the lower growers more on the perimeter, we also tried to group the varieties en masse to create a more natural look. 

When we completed the planting of each island, we added 1/2" (1.3cm) of soil to cover the jute mesh as our last step before launch. It turned out that our first island required 6-7 cubic feet (.17-.2 cubic meters) of soil to fully plant that 80 square foot (7.4 square meter) surface area, the two others were 50 square feet (4.6 square meters) and 25 square feet (2.3 square meters). With just the five of us working, we planted and launched all three islands in approximately five hours, not including the gathering of materials.

To launch our islands we worked them towards the shore, even though they had garnered quite a bit more weight after planting. After attaching very strong cabling to the bottom of the island, a concrete cinder block was attached once the flotilla’s final position was reached. Two of the three islands that we created were anchored using this method and the third was allowed to float freely. It was truly amazing to see how much weight our islands could hold during the launching process, but we're still trying to locate where Renee and Sean ended up on that last one (below, lower right).

The unique makeup of the islands adapts to different uses while using the same basic material. Along with the obvious environmental advantages that they have, the potential aesthetic appeal is unlimited as well. By using a showy mix of plants and even changing the plant pallet on a seasonal basis, enjoyment of the islands can extend year round.

Another project I learned about while gathering information for this article required the connecting together of many islands, forming a Caspian tern nesting island at Summer Lake in southern Oregon USA. While one would expect that many plants might have been a part of that mix, in reality, sand was spread across this 20,000 square foot (1,858 square meter) area, more appropriate in that circumstance. It is my hope that this type of technology will be much more prevalent in the coming years as it is a system with such potential that it should be brought into the forefront in many different applications.

I want to thank both Renee and Sean for sharing this experience with the hands-on demonstration group. We were able to enjoy the working day for nature and it opened our eyes to an incredible idea, a tool to be utilized in our future endeavors. 

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