Woolston New Weir and River Mersey Diversion Available to Purchase

The Woolston Weir and River Mersey Diversion project involved provision of a new hydraulic control structure, diversion channel and ancillary works on the River Mersey, near Warrington, for the Manchester Ship Canal Company. The weir is a substantial structure, nearly 80 m wide. It includes the largest low-head, air-regulated siphon weir to date in the UK, with nine bays, each 4 m width, plus 17·8 m wide ‘ogee’-type weirs either side, and a fishpass. Design involved extensive physical and numerical modelling. The weir was built in dewatered open cut in difficult ground, within a new channel some 600 m length cutting across an ancient loop in the Mersey. The scheme has provided an economic means of closely controlling a wide range of flows, for flood and navigation purposes, consistent with a pleasant river environment.