Artificial Floating Islands May Help You Resolve Issues in Ponds

In this article, we interview Autumn Boos, Director of Sales and Marketing for Midwest Floating Island, about artificial floating islands and what problems they can help communities or even individual property owners solve.

Useful Community Development (UCD): What are floating islands?

Autumn: Floating islands are sometimes called man-made floating wetlands or floating treatment wetlands (FTW’s).  BioHaven® islands are a thick porous mat which floats on the surface of the water with vegetation planted in pre-made holes.  These plants grow long roots down below the island. 

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Benefits of Floating Islands

UCD:  What are the benefits of having a floating island?

Autumn: There are multiple benefits of floating islands. Two of the biggest benefits are improved water quality and diverse habitat.

These floating wetlands can help reduce algae by cycling phosphorus and nitrogen. They can reduce total suspended solids which cause cloudy water.

The second main benefit is creating diverse habitat.  That habitat is “above the island,” “in the island,” and “below the island.” 

The surface of the island is very attractive to the frogs and the turtles. We also recommend native plants that are appealing to the pollinators. So if you are in the area where the monarch butterfly migrates, we might plant with swamp milkweed, for example, or other plants that would be important habitat for the birds and the bees. This habitat helps them with a more nutritional plant than some of the annuals that they might encounter in other people’s gardens. 

In the island and on the roots below the island, there is a sticky biofilm forming.  This helps grab microbes and bacteria which colonize to help break down the pollutants.

In the island itself, you have a tremendous number of organisms living in the porous holes of our matrix.  In some cases those macroinvertebrates can be rare for the estuary because it’s providing a different habitat than on the shoreline.  Those macroinvertebrates are very important.  In fact the island doubles in weight during the first year because there are so many macroinvertebrate and other animal species living in the island.

There is a sticky biofilm that naturally forms on the roots as well as within the island, and that sticky biofilm is going to help capture different types of microorganisms.  Those microorganisms, which really are the beginning of the food chain, will be grazed by fish and other organisms, so you really see the food chain going on.  So the islands are providing diverse habitat above, inside and below.

UCD: Would you like to mention briefly any other benefits?

Autumn: Some people value islands for shoreline protection.  We see that particularly down in the Gulf area where floating islands provide shoreline protection to help restore the marsh by reducing wave chop.

People also can use them for beautification and “soft-scaping”.  In urban areas where there are metal walls along the waterways, the floating islands provide a way to make the waterway more attractive and provide natural habitat.

UCD: Are there other  advantages for the environment?

Autumn:  Floating islands have minimal environmental impact during the installation process.  You do not need big earth moving equipment for a standard island in a pond.  You can simply plant the islands on the grass and push the island into the water.  They are a great retrofit.

One of the other great benefits is that the islands float so the plants do not suffer from draught or drowning as water levels change in the pond. 

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Construction, Sizes, and Locations of FTWs

UCD: How exactly are these constructed?  What makes them float?

Autumn:  Our islands are made of recycled PET, which is a plastic used in water and soda pop bottles.  This PET has more UV resistance than other plastics because of its molecular structure.  This material is a good choice because it doesn’t have the problems that the microbeads have.  PET is inert, which means it won’t biologically degrade or leach, which is why this is often used for packaging foods and beverages.  The great part is that we keep bottles out of a landfill and instead use them to clean the water.

We add a foam that is a marine grade foam approved by the Coast Guard.  So that is what makes it float.

UCD:  What sizes and shapes do you commonly install? 

Autumn:  Islands can range in size from small koi pond sizes up to very large.  The large projects are made by connecting modules together.

UCD: How do you determine the size of an island?

Autumn:  We consider how dirty the water is now, how much movement of the water there is (since stagnant water would require larger islands than a pond where there is considerable water flow), how big the pond is, the average temperature of that area—in warmer climates there is more biological activity which cleans the water faster, and then your time frame.    

UCD:  How would a typical community become interested in these islands, and how would they decide on locations?

Autumn: The ideal use of an island would be in a stormwater pond or wastewater pond.  Islands  in a pond do not need to be removed for the winter.  They can stay out year round, which reduces the maintenance cost.  So ponds are an excellent use of a floating island.

You can use floating islands in lagoons, rivers and lakes but you need to think through the anchoring requirements.

Typically someone would contact us to be referred to the appropriate person in their area. 

It’s a custom solution because we vary the design for the water body needs.  We usually talk with people individually to figure out what the right size is.  We encourage people to call and have a conversation.

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More About Improving Water Quality through These Artificial Structures

UCD: What amount of time typically is required before water cleaning benefits start to be realized?

Autumn:  The biofilm forms quickly but there is usually a lot of water to clean.  We do ask customers what their goal is because their time frame affects our recommendation on the size of the island.  If you want your water cleaned in six months, you need a much larger island than if your time frame is two years. 

UCD: Could you sum up how floating islands lead to water quality benefits? 

Autumn: The floating islands provide a place for microbes and bacteria to grow.  Microbes and bacteria are already in the water.  We’re not adding them; we’re providing a place for them to colonize because we are adding a tremendous amount of surface area and providing a fabulous place for them to flourish.  As they grow, and they are active and moving, that’s when they are breaking down the pollutants in the water.  The dirtier the water, the more active the microbes are, the more water cleaning going on.

UCD:  Talk to us about the cost.  Are they expensive, and how does the cost compare to other ways that you might approach cleaning the water?

Autumn:  Water is complicated. Cities and other groups have many tools and there is never just one perfect solution to solve all water problems.  

First, we encourage people to find ways to prevent the fertilizers and pollutants from continually entering the water.  However, islands are a wonderful option once the excess nutrients and pollutants are in the water body. Our product is competitively priced and ideal for retro-fits. Since we are a custom solution, we prefer to talk individually with people to see what solution will work for them.

UCD: Would you like to say more about the role of plants in all of this?

Autumn: The islands have the ability to clean the water even without plants, but we do recommend using plants.  Pulling up nutrients from the roots only accounts for about 5 to 7 percent of the water cleaning.  People are always skeptical about that, but it has been demonstrated in many pieces of research that that is true. 

However plant roots play a very important role. Those long roots are doing a couple of things:  (1) They are slowing down the movement of water which helps with settling; and (2) The microbes and the bacteria get stuck in the sticky biofilm on the roots and help with cleaning the water.  So not only do we have the top part of the island, but we have two feet down where all those roots are underneath the island where water cleaning is happening also.  Not to mention there are benefits to the food chain.

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Worldwide Applicability of This Technique

UCD: You're working in the American Midwest.  Are floating islands common in other parts of the world?

Autumn: We are a licensee of BioHaven floating islands.  The inventor is Bruce Kania in Montana.  Floating Island International licenses our technology for manufacturing and works with people all around the world. There have been more than 7,000 islands installed around the world. Islands have been installed in Canada, New Zealand, Australia, China, Sweden, all over the world.   Recently this summer there was a project put into Ecuador. 

UCD: Thanks for your time, Autumn.  How would people obtain more information about floating islands?

Autumn:   Start with the Midwest Floating Island website to learn more.  We have a number of case studies and research projects posted.

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Here at Useful Community Development, we believe that tiny clean water projects, including back yard ones, will lead to better consciousness of water quality everywhere. For more about water quality at the homeowner level and then the neighborhood and community level, check out the stormwater runoff page as a starting point. 

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