While the Tarholm Sewage outfall on the lower River Ayr was a controversial and unwelcome addition to the river by many, plans were passed and the works went ahead this summer. Contractors recently completed the pipe track and the concrete outfall structure and ART were asked for advice and assistance with installing green bank protection as SEPA preferred this option to traditional and hard engineering methods.
After initial discussions, ART were engaged to install willow spilling with the condition that it was completed before the end of September. We stockpiled willow cuttings and poles, keeping them alive in troughs of water and in the river itself for around 20 days before use. Soaking the cuttings appears to improve rooting success.
With all materials on site and a looming deadline, last week we set about installing the willow and after a few hards days work, we believe this should soon develop into an erosion resistant, living and naturally armoured banking.
The images below show the works progressing to completion.
At the start of the works
Willow spiling with willow and hardwood brash faggots to reinforce the toe of the bank and to infill behind the spilling. These should trap sediment carried in suspension in the river.
We installed to levels of the spiling to help stabilise the slope.
There’s a lot of willow required for this type of work
As we completed the work, we were pleased with the results and the outfall was connected.
We will post updates of this as time progresses to show just how effective these techniques are. By next spring the willow should be well rooted and bursting into life.
