FOOTBALL TRAINING facilities used by Premiership clubs playing Manchester United, as well as visiting international teams, have been saved by a living engineering solution.
The Cheshire site near Wilmslow was threatened by rapid riverbank erosion until supplier contractor Willowbank won the £40,000 contract to reinstate the edge of the River Bollin.
'The 3m high bank on the river was over-steep and the eroding toe was causing the bank to crumble into the river, ' says Willowbank partner James Hector. The Environment Agency approved solution was to stabilise the toe and bank by installing three tiers of live willow spiling.
The company says this is the most common and best known green solution for bank revetment. The technique uses woven willow to form flexible, growing structures which resist and deflect water flows.
This enables the bank and vegetation to regenerate naturally and stabilise preventing further erosion.
For three weeks in November, four skilled spilers, or willow workers, worked along a 100m river stretch to produce a natural retaining wall, capable of rejuvenating itself.
The stakes are driven vertically through the slip circle into the riverbed and interwoven horizontally with willow shoots to establish a dense root mass and top growth.
The willow will require annual maintenance in the winter to control top growth. This technique offers protection against erosion to both the toe and upper bank.
The location of the site, in an exclusive part of Cheshire, brought challenges of its own. 'This is the first time we've had to duck while working to avoid low flying helicopters whisking premiership footballers and wealthy businessman to and from the location, ' said Hector.
With access to the eroding section of riverbank crossing a championship golf course, Willowbank also laid a vehicle track to protect the grass.