Geared to protecting around 400 homes and businesses in the area, the Oakenshaw Beck flood alleviation scheme at Agbrigg, Wakefield was planned following the severe floods of June 2007, which caused devastation across the district.
The scheme, which has been developed in a partnership between Wakefield Council and the Environment Agency, is being carried out by Main Contractors CA Blackwell.
The result will be a flood bank and flood wall, securing an area of land that will temporarily hold floodwater resulting from heavy rain storms upstream on Oakenshaw Beck.
The works comprise the following main elements: excavation of made ground (ash) fill material from the main site and disposal on the fill site; construction of flood embankment control structures; a pumping station and control house; a parapet wall, floodwalls and floodgates. A diversion weir, channels, ponds and low flow culverts are also being constructed. Miscellaneous works include the construction of fencing and a cable pulling chamber. The flood embankment is approximately 350m long and constructed of cohesive (clay) material with a 4m wide crest and 1 in 3 side slopes, with a clay cut-off extending below base level.
The flood wall is of traditional construction in reinforced concrete and comprises of two separate lengths, at the upstream and downstream ends of the scheme. At the downstream end, the flood wall is approximately
74m long and up to 1.5m high. A length of around 30m is a direct replacement for the existing culvert parapet wall adjacent to the A638 Doncaster Road.
At the upstream end the flood wall is approx. 75m long and up to 1.4m high. The flood wall is being constructed without cladding except for the parapet section, where masonry cladding will be used, re-claimed from the existing masonry. Three floodgates are incorporated into the scheme at locations where access through the defence is required. Two floodgates are required at the upstream and downstream ends of the scheme. The third floodgate is required for access to an allotment site.
Currently the project is going very well, with the overall works 60 per cent complete and construction of the embankment 90 per cent complete. “The contractors are doing a very good job and we are very pleased with them” said Paul Maddison of Wakefield Metropolitan District Council.
Work started on 4 April 2011 and is planned to be complete by September 2011.