Currently, tunnelling is in progress under several roadways, including the Lander Road crossing, the railway line near the Meyer Road and Freebairn Drive intersection and Papta Road at the Lonsdale road intersection at Hallett Cove. Tunnelling is expected to commence under Main South Road near Glenthorne Farm and the Happy Valley water treatment facility in late August. Preparations for tunnelling underneath the Southern Expressway will also commence.
Contractor Winslow Infrastructure will complete a 405 metre microtunnel using an MTS-2000 slurry machine and 1,800 mm outer diameter separator unit. The technique has been chosen to tunnel under roads and rail to ensure minimal disruption to traffic and the general public during the completion of the works. The microtunnelling works are expected to take approximately five months to complete.
SA Water has previously said that the main challenges expected in using Trenchless Technology include avoiding existing services and groundwater. Where practical, the pipeline will be located to avoid underground utility services and, where this is unavoidable, the relocation of services will be arranged with the relevant authority.
The 11.5 kilometre pipeline will deliver desalinated water from the Port Stanvac site to the Happy Valley treated water storages.
The majority of construction activities will be completed by the end of 2009, but pipeline construction is expected to be completed by mid-2010.