The $20million Cowan Wastewater Scheme is part of the NSW Government’s $150 million Priority Sewerage Program (PSP) which aims to deliver improved wastewater services to unsewered communities in Sydney, the Illawarra and the Blue Mountains by June 30 2014. In order to complete the $150 million program Sydney Water Corporation entered into an Alliance arrangement with MWH Australia, John Holland, UGL Infrastructure and Manidis Roberts.
UEA was contracted by the PSP Alliance to complete the detailed design and construction of the pressure transfer and gravity mains between the township of Cowan and the new discharge man mole over the existing gravity carrier in Berowra. The scope of works involved the installation of:
- 2,289m of 160mm PN20 PE pressure main
- 492m of 180mm PN20 PE gravity main
- 90m of water main in rock ground conditions
Underboring was the chosen methodology to complete the works as it allowed vehicle traffic to be maintained at all times along the Old Pacific Highway and significantly reduced the restoration costs had open trenching been completed. UEA utilised three Horizontal Directional Drilling (HDD) rigs to complete the works within the tight timeframe set by the client.
Construction on the Cowan Wastewater Scheme started in early 2013 and is expected to take approximately 12 to 18 months to complete. Connections are expected to be made available by mid 2014. Once connected, residents will enjoy the benefits of reticulated sewerage services, rather than relying on septic tanks and a regular pump-out service.
Photo:UEA completing a 374m pilot bore with 82m of lift using the Vemeer D60 x 90 directional drilling rig.