Willow Spiling on the Ayr

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One year has passed since ART installed willow spiling on the River Ayr at the new Tarholm sewage outfall

At the start of the willow installation.

Installing the willow spiling last September

It takes a lot of material to build a strong structure like this and while it doesn’t all root, some does and this provides a living barrier that resists erosion.

This technique was used after SEPA recommended a green engineering solution rather than a traditional hard engineering approach that would have included rock armour or rip rap. Scottish Water asked for ART’s advice and assistance and they installed a length of willow spiling (woven willow) along an area of bare banking once the outfall had been constructed.

That was one year ago exactly so ART revisited the site at the weekend and took more photos. Over the course of the year , the willow has rooted and grown, so much so that they have already taken a few cutting from the plants for use elsewhere.

Exactly one year after the willow was installed, it is easy to see the benefits of this work

Although cuttings have already been taken from these plants, it is a strong and robust structure that will last for decades with little management.

Willow spiling is a low cost solution for eroding banks and is much more environmentally friendly than hard engineering. It provides shade and habitat and is very resilient to high water floods events. During the course of the last year this section of bank has been underwater for weeks and the rooting willows survived a long period of drought although the top terrace did suffer as the plants were just developing roots when the dry spell hit. Next year, they should catch up with the lower terrace as they have now rooted.

The structure can cope with floods and high water events. It spent several weeks underwater before the end of last winter

Another benefit of this type of approach is that it traps suspended sediment from the river and builds banks. Nearly 30cm of silt has been deposited behind the lower terrace within the first year

This type of approach can also be used to protect banks eroding elsewhere within the catchment. ART are happy to advise owners and anyone interested in these using techniques.

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