Plastic islands being used to restore African lake


September 21, 2012

One of the BioHaven Floating Islands, from a previous project (Photo: Floating Island Southeast)

One of the BioHaven Floating Islands, from a previous project (Photo: Floating Island Southeast)

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As the ever-growing giant flotilla of floating refuse known as the Great Pacific Garbage Patch will show us, we shouldn't be putting plastic waste in our waterways. A new project, however, is aimed at helping the environment by doing so ... in a roundabout way of speaking. The participants plan on taking several artificial floating islands made from post-consumer plastic, planting papyrus on them, and then using them to help rebuild the ecosystem of Africa’s Lake Naivasha.

Located in Kenya’s Rift Valley, the lake was crystal clear 30 years ago. Since then, a 20-fold increase in the local human population, along with foraging activity by water buffalo native to the region, has resulted in massive clearing of the lakeshore papyrus plants.

Like other aquatic plants, papyrus serve a vital role. Acting as biofilters, they trap suspended sediments, plus they remove toxic substances and excess nutrients from the water. Unfortunately, the destruction of much of the lake’s papyrus plants has led to a marked decline in its water quality.

One of the last stands of papyrus along Lake Naivasha (Photo: University of Leicester)

The restoration project is being funded by the German REWE Group. It involves the participation of UK tea producer and flower grower Finlays (which grows flowers in the region), and is being led by Dr. David Harper, a senior lecturer at the University of Leicester.

The team plan on introducing a new population of papyrus to the lake, at a spot where silty water from the Malewa River enters into it. Those papyrus will be planted on a series of BioHaven Floating Islands, made from recycled polyester drink bottles by North Carolina-based Floating Island Southeast.

Each BioHaven island is essentially a floating mat, made up of multiple layers of a plastic matrix bonded together with marine-grade foam. This provides a highly buoyant surface for plants to grow on, while allowing their roots (which dangle beneath the island) to both act as a sediment filter, and as a home for aquatic microbes. Those microbes feed on nutrients that might otherwise lead to excess algae growth – a service also provided by the plants themselves.

Additionally, the roots should serve as feeding grounds and nurseries for fish, while the five meter (16 foot)-tall stalks of the plants should make a good habitat for birds.

The islands have been ordered, and will be anchored in place once the papyrus is planted on them. If they prove successful at their first location, additional islands will be installed at other locations along the lake shore.

Sources: University of Leicester, Floating Island Southeast

About the Author
Ben Coxworth An experienced freelance writer, videographer and television producer, Ben's interest in all forms of innovation is particularly fanatical when it comes to human-powered transportation, film-making gear, environmentally-friendly technologies and anything that's designed to go underwater. He lives in Edmonton, Alberta, where he spends a lot of time going over the handlebars of his mountain bike, hanging out in off-leash parks, and wishing the Pacific Ocean wasn't so far away. All articles by Ben Coxworth

I used to fish on lake Naivasha growing up - a very beautiful place! I remember well the great papyrus "groves" along the shore, and its sad to hear these have become diminished. The lake area is a bird-watcher's paradise and its very good to hear that there are those who are going to great lengths to preserve this natural treasure of Kenya!


So wait, are they just assuming the various toxic chemicals from the plastic won't poison the lake? Or are they hoping the bio filters of the papyrus will do the job? That was my initial question from reading the title and was never really addressed in the article.


If I recall correctly, the lake is already contaminated from the flower industry, which exports and sells to Europe.

David Blume says cattails are one of the few plants that can remove endocrine disruptors, but maybe papyrus can also?

I hope to see more on this topic.

Mary Saunders

I am not sure this is such a great idea. Remember all the tires they threw into the Ocean near Florida to "help" marine species?

Srihari Yamanoor

This is a great idea that I had several years ago and I am pleased that someone else actually went to the next step of trying it out. The area I had in mind is the gulf coast outside of New Orleans. Loss of outer bank islands and sandbars was one of the essential contributing elements in the huge scale of damage inflicted upon the coast of Louisiana and the city of New Orleans. As the delta shrank so also did the ecosystems ability to absorb & stabilize soil & excess nutrients flowing out of the Mississippi river, hence the ever expanding annual dead zone. Natural forces are estimated to fix this over many centuries. We could fix this inside of a decade or two with artificial islands filtering & stabilizing sediment & nutrients at a speed nature cannot match by creating habitat for flora, fauna, & fish.


Now you are talking! Some great ideas coming through from this which will I am sure be applied in the near future. This beats the hell out of sending crackpot rovers to Mars!!

More of this is needed on our planet righ tnow. IOn this time of wars and troubles where humanity is pitched against one another - marvellous advances which make us proud are almost extinct

Elsdon Ward

Interesting Comments! I'm part of the Floating Island International network, and based on feedback from all over the planet it's very plain to see that cycling nutrients out of water, especially phosphorus, is one of today's greatest challenges.

Quick note about possible leaching of harmful chemicals. The islands referenced here use a matrix of recycled polyester...which is one of the inert polymers, as in water bottles. Plus, based on the BioHaven design, the plastic matrix will be layered with biofilm within a day or two of launch. In dozens of independent third party studies no trace of harmful leaching has come up. But still a valid concern.

Bruce Kania

I want these in New Orleans!

it tastes like burning

we have to stop the hide and seek program in dealing with plastic we gave to stop thin hd films and start recovering the same already destroying our forest water resources and agri fields

Deeaar Krishnan Krishnan
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