DOCK DIVE: Birse Construction is tunnelling under historic docks as part of a £14.8M wastewater scheme in Birkenhead, Merseyside. The firm is using a Lovat TBM to drive a 2.1m diameter, 178m long tunnel beneath the Alfred Dock to connect two, 28m deep and 4.5m diameter shafts forming part of the Lower Mersey Basin project for North West Water. As well as the tunnel, the company is involved in construction of a pumping station and extensive modifications to an existing screening plant at Wallasey, a diversion chamber to the existing 3.2m diameter brick 'Great Culvert' which carries the flow of the River Birket and discharges into the Mersey estuary at Birkenhead. The culvert is also collector sewer for foul and stormwater flows from Birkenhead. The scheme is part of North West Water's latest £200M project to clean up the River Mersey. By next year, improvements will provide secondary biological treatment at a new plant at Birkenhead's Morpeth Dock and other plants across the region.