Project Overview
This project represents a critical renewal of Central Coast Council’s West Gosford sewer network, replacing approximately 2.2 kilometres of ageing major sewer infrastructure to address structural reliability concerns and strengthen the long-term resilience of this essential asset.
The works involve the construction of large-diameter sewer rising mains using a combination of open trench, Horizontal Directional Drilling (HDD) and above-ground pipeline installation methodologies, enabling the new infrastructure to be delivered across a range of technically and environmentally complex conditions.
The works are being delivered across three separable portions and include DN800 PE100 sewer rising main installed by HDD adjacent to Narara Creek, DN800 PE100 pipework installed through the golf course, and the conversion of approximately 215 metres of the Western Transfer Main from an underground to an above-ground alignment. The above-ground works incorporate OD660 MSCL pipelines supported on screw piles and headstocks, together with thrust blocks, access slabs, ladders, handrails and expansion mechanisms. The scope also includes DN600 DICL pipework, tie-ins to existing infrastructure, permanent access provisions, temporary works, shoring and dewatering, demolition and disposal of redundant infrastructure, polywelding, and comprehensive testing and commissioning.
A defining feature of the project is the complexity of the surrounding environment. Construction interfaces with environmentally sensitive wetlands, Narara Creek and areas of archaeological and Aboriginal heritage significance, requiring careful planning and strict compliance with environmental and heritage requirements. Works also involve the management of acid sulphate soils and other contaminated materials, while construction activities must be coordinated around key stakeholders including Gosford Racecourse, the golf course, showground, Central Coast Council and the surrounding community. These constraints require an integrated approach to construction methodology, environmental management, stakeholder engagement and sequencing to successfully deliver the works while minimising impacts to surrounding land uses and sensitive areas.
