River Bann Pumping Station, Co. Londonderry
Doran Consulting provided the design services to Williams Industrial Services Ltd on this NI Water Design & Build project to construct a replacement raw water abstraction pumping station to transfer flows of up to 40Ml/day from the River Bann at Castleroe Wood, near the Cutts, Coleraine, to Ballinress Impounding Reservoir for treatment at the Ballinress Water Treatment Works prior to supply to the Coleraine area. The scheme also incorporated the construction and commissioning of new bypass pipework to Ballinrees WTW and the upgrading of the existing pumping main outfall structure at the impounding reservoir.
The new intake from the River Bann allows river water through dual 600mm diameter pipes from the River Bann feed into inlet screen section, which comprises two "Brackett Green" band screens operating as duty/ standby. Screen washwater is fed from main pump discharge main via PRV.
The design is based on a dry well/ wet well configuration with screened water flowing into a reinforced concrete wet well sump adjacent to a drywell housing four "Flowserve" multistage pumps operating as Duty, Assist 1, Assist 2 and Standby. Each pump is fitted with automatic discharge valve.
The wet well was hydraulically modelled and the results incorporated into the construction. A surge analysis was carried out on the rising main and two "Flo-Dyne" 12.5m3 surge vessels were installed on the discharge main. The Control Building has pre-cast concrete piled foundations and is constructed in structural steel portal frames with roof and walls made up of insulated cladding panels.