Construction: AWG Construction Services Ltd/BW Partnership (Midlands Omnibus)
Client and Designers: British Waterways
Embankment 4 on the Coventry Canal at Polesworth is 1210m long and up to 4m high and had been found to be unstable. The site is adjacent to, and subject to flooding from the River Anker. A thorough ground investigation was undertaken and a proposed solution to stabilise the embankment put forward. In addition to the slope stabilisation works canal wall and towing path improvements were carried out. Alternatives methods of stabilisation were considered. The cheapest option was rejected due to environmental considerations. The solution used was reinforced concrete bored piles were installed in the toe of the embankment to protect against a deep-seated failure of the slope. Additionally a toe berm was installed at the base of the embankment having the dual purpose of providing a level platform for the piling operations and providing resistance against shallow slips within the embankment.
The initial embankment stabilisation works were carried out in summer but the towpath was kept open for use by the public. This required careful management of pedestrian and construction traffic. To ensure smooth delivery of the works extensive community relations work was carried out including discussions with angling clubs that use the length.
The site is a very important wildlife corridor of reasonably high nature conservation value, otters are present on the River Anker, and Warwickshire County Council aspire to develop adjacent area as a nature reserve. Contractors used best practice to respect and protect the value of the site. The haul route passing through Mrs Hadley’s orchard took the least destructive route avoiding the riverbank and the mature ash tree. Opportunities were taken to create new habitats during the works, these included scraping out shallow ponds, using wood chips from tree works to make grass snake breeding sites, as well as construction of an otter holt.
The scheme was assessed by Dr Mark Robinson, Waterway Conservation and Regeneration, British Waterways and verified by Dr Richard Hunt, Ove Arup and Partners.