The use of pre-planted coir fibre modules in bank stabilisation. The AGA Group pioneer greener solutions to erosion control

Using plants in this way is easier, more economical and more aesthetically pleasing than many of the heavy engineering solutions. By this method several typical lakeland and waterways problems can be solved in one go, and it is something that could easily be taken up by the pondkeeper and wild fowl conservationist too.

Article and photos by Tom Roach 

With the environment moving steadily up the political agenda, business is now trying to find new ‘soft’ engineering solutions as opposed to more traditional ‘hard’ revetment techniques. The recent summer rainfall has sparked debate, not only how to protect areas from flooding but the associated risks that flooding brings. Erosion of rivers and lakes is a natural process and ‘hard’ engineering techniques that have been employed in the past are increasingly being seen as inappropriate and unsustainable. This has led to forward thinkers finding innovative natural ways to curb the onset of erosion using techniques that would occur in nature.
The pre-vegetated coir rolls showing plants well established at the nursery.One of the solutions offered by sustainable aquatic practitioners such as the A.G.A Group is the use of coir; this material has a number of diverse functions and can be sustainably and responsiblyRecently the AGA Group acquired the vast growing facilities of the aqautic plant nursery Merton Hall Pond: All the plant production has been given over to providing material for the coir modules and reed bed schemes. sourced. When the coir is compacted into rolls it can be positioned in front of eroded banks and backfilled thus creating in effect a new bank. These pre-established coir rolls serve a number of functions other than erosion control and act as habitat for a number of valuable species. Indeed after 12-18 months the vegetation has grown sufficiently that it is hard to tell that a form of erosion control has been employed.

Coir has been used in this way for a number of years and has been widely accepted by regulatory bodies such as the Environment Agency as a more sustainable form of erosion control than hard revetments. Where the use of coir differs from harder techniques is that it is in balance with the natural system of the river or lake and does not have some of the negative impacts that are associated with hard erosion control measures. The use of hard revetments is proven in many cases to just move the problem to a different area, be it downstream or to another section of the lake.

OTHER BENEFITS OF USING PRE-VEGETATED COIR MODULES

In working with nature and using sensitive bio-engineering techniques such as this, there is a real opportunity to combat erosion while increasing habitat areas and improving biodiversity. In establishing marginal aquatic growth Pallets of reeds and sedges are used in floating island and are very effective as 'hoover' of excessive nutrients in the water.: Where there are wildfowl, a protective cover can be provided that the birds can actually nest on.Where there is likely to be heavy grazing from cattle, the coir modules can be provided with protective mesh.there are a number of associated benefits which can help to improve the habitat value of the site. The pre-vegetated coir-fibre modules have been widely tested and have proven to be very successful in improving water quality, increasing biodiversity, stabilising banks and reducing sediment transport.

Because this technique is effectively building a new front to the bank with materials that will ensure that it becomes completely naturalised it is possible to be fairly imaginative with the bank shape. This offers scope for creative planting behind the coir rolls and the opportunity to stop erosion naturally and enhance the intrinsic value of the site.

A.G.A GROUP : PIONEERS OF NATURAL SOLUTIONS

Companies such as the A.G.A Group who pioneer this type of approach offer natural solutions to sometimes complex problems. Working with nature to solve these problems is fast becoming the accepted methodology and as more The underside of one of the pallets clearly demonstrates the sort of root growth that the plants are capable of.: In turn this root growth helps reduce sediment and pollution.people take notice of the environment the practice is sure to spread. This approach can only be welcomed, as we increase our understanding of the natural environment so we can find solutions that not only serve our needs but enhance biodiversity and habitat.

COMING SOON: We'll be seeing how well these techniques work in a 'problem pond' full of ducks when we hide exposed liner and damaged banks with AGA's pre-vegetated coir modules ('coir sausages' I call them).