Girdwood Contracting Pty Ltd was engaged by North East Water for the Design & Construction of the Oxley Sewerage Scheme. The project included 3km of reticulated sewer mains, inspection shafts and manholes laid on grade through established streets and residential areas. The sewer scheme included 2x in-ground pump stations, (1x 4m deep and 1x 7m deep) as well as an above ground high pressure pump station with a 16km HDPE rising main from Oxley to Wangaratta..
Challenges included construction of deep sewer sections (6m) adjacent to the King River. Water inflow to the construction zone was extreme and the use of spear point dewatering to lower the water table was required in order to achieve pipe installation on grade. As we moved from the deepest sections, free draining bedding material was used to give the water a path to disperse away from the construction zone.The 7m deep in-ground pump station was also located in the water inflow zone. Again, the spear-point dewatering system allowed the water table to lower sufficiently to complete the installation.
The above ground pump station construction was Tilt-up concrete panels on a concrete slab with colour-bond metal roofing. Due to the proximity of houses to the pump station site, particular attention was paid to noise levels from the pump building. Acoustic rated access doors and ventilation cowls were installed to prevent noise transmission.