Greenfield developments require significant input from all sectors of the utility industry. Here, we look at the process of connecting the new Wyndham Harbour precinct in the Melbourne suburb of Werribee to water and wastewater services.
Wyndham Harbour is an exclusive new marina community located in Melbourne’s west, directly overlooking Port Phillip Bay. Featuring a variety of open spaces and community facilities, the focal point of Wyndham Harbour is Marina Square, a public meeting area overlooking the marina.
In 2016, the Wyndham Harbour Marina will become operational and will be Melbourne’s new centre for recreational boating on the western side of the bay. Additional facilities will follow in future stages, such as dry berths and an exclusive Marina Club.
As with any greenfield residential development, there is significant work to be done to connect the community to essential services.
City West Water oversaw the water and wastewater connections. Together with major project consultant Watsons, they issued a range of tenders calling for qualified subcontractors to bring these essential services to the site.
BMD Constructions was engaged as the principal contractor to complete the marina and residential civil works for the project – the scope of works included construction of 8km of water supply main; 4.6km of rising sewer main and a 7m deep sewer pump station; and 1,000m of 1,800mm diameter stormwater drain, among other items.
All of the teams involved in the project were keen to utilise cutting-edge technology for the connection of the water and wastewater services, and this desire came to the fore particularly in the construction of the sewer main.
Working with Watsons, the project team reviewed the options for the sewer main construction, and it was decided that horizontal directional drilling (HDD) would be utilised for the installation of 844m of the sewer rising main under the environmentally sensitive Grahams Wetland Reserve.
Watsons consulted with AHD Trenchless throughout the HDD design process, reviewing the works methodology, hydraulic frac analysis and bend radius to ensure that the construction met with all design and environmental protection criteria.
Construction commenced in February 2015, and the team from AHD Trenchless successfully installed 844m of 200mm diameter rising sewage main outfall in ground conditions including below water table sand and marine clay in record time and within budget.
Other challenges in the HDD installation included keeping the borehole from collapsing, and this was achieved by using a customised drilling fluid to static charge the borehole.
The exit side for the HDD shot was in a market garden farm, which created access issues during wet times. Great care also had to be taken to not disrupt their production schedules and day-to-day activities.
Works continue towards the overall completion of the Wyndham Harbour project. The end result will be a dynamic, integrated residential, commercial and marina complex based on principles which produce a balance in ecological sustainability, commercial viability and social responsibility.
The project is currently on track for overall completion over the 2015/16 summer.
