JBA Bentley scores £19m Forgemasters’ contract

The Leeds-based design-and-build contractor will deliver civil flood alleviation works at the Brightside Lane site in Sheffield.

The civil engineering scheme will intercept the Bagley Brook culvert in the Lower Don Valley as it enters the Sheffield Forgemasters site, enabling storm water to be diverted, stored, and gradually transferred into the River Don.

An extensive underground catchment system comprising storage tanks, a cross-site transfer tunnel, and a pumping station will manage large volumes of water by rerouting and containing it during critical periods, then releasing it back into the river at a controlled flow rate.

To facilitate this, a section of flood wall along Sheffield Forgemasters’ boundary with the River Don will be repositioned to make way for a new outfall structure.

From here, the pumping station will discharge storm water back into the river at a rate of up to 8,000 litres per second.

These two years of flood alleviation works are part of Sheffield Forgemasters’ planning obligations linked to the construction of a new 13,000-tonne forging line, currently underway adjacent to the Midland Mainline railway.

Craig Fisher, programmes director at Sheffield Forgemasters, said: “We have already made huge steps towards flood prevention on the site, but the Bagley Brook transfer system will address a known flood-risk which can affect both our plant and this part of the city.

“The brook, which runs through an enclosed culvert along our northern boundary and into the River Don, was contained in the Victorian era, and the culvert simply can’t cope with an excessive flow of water, causing it to breach in heavy storm conditions.

“The new transfer system will allow storm water to be diverted from the culvert and contained in large attenuation tanks, before being transferred to the River Don via a new underground pumping station, near to Abyssinia Bridge.

Graham Frudd, contracts manager at JBA Bentley, said: “We are delighted to be working with Sheffield Forgemasters on what is a major flood alleviation project in the Lower Don Valley.

“JBA Bentley will undertake construction of a new weir chamber, integrated into the side of the existing Bagley Brook culvert, to allow a proportion of storm water to be redirected from the Bagley Brook culvert to a new pumping station at the side of the River Don.

“This will involve sinking a five-metre shaft to receive a tunnel boring machine which will drive a tunnel, twelve metres deep, for 320 metres across Brightside Lane. This will be launched from the 15m diameter shaft, which will double as storage and a pumping station.”