Sydney – Duplication of Drinking Water and Wastewater Pipelines for Sydney Water
BESSAC is contributing to the construction of several major tunnels as part of projects to duplicate a primary drinking water pipeline in Thornleigh and a wastewater pipeline in Rouse Hill, in Sydney, Australia. This work is being carried out for Sydney Water by the Ironbark joint venture, a partnership between Bouygues Construction Australia and our sister company Rob Carr Pty Ltd.
This project includes two key operations directly supporting Sydney’s demographic growth:
- TIOM: construction of a microtunnel through Sydney’s abrasive sandstone for a drinking water network.
- MNW: construction of a microtunnel for the installation of steel pipelines for a wastewater network.
FOCUS on the two projects:
TIOM: a microtunnel in a demanding geological environment
For the TIOM project, BESSAC supplied the “Jane Starkey” microtunnelling machine, along with a specialized team.
The machine excavated a 1,200-meter DN1800 tunnel between the Thornleigh reservoir and the Thornleigh–Wahroonga pumping station, progressing through Sydney’s highly abrasive sandstone.
MNW: installation of wastewater pipelines
For the MNW project, the two drives of 80 m and 700 m in DN1500 were completed in the fourth quarter of 2025.
Thanks to optimized planning, the DN1000 steel pipes were then welded and inserted into both tunnels in record time.
An exemplary collaboration
These achievements illustrate the value of close cooperation between the client, contractors, and specialized partners. They also demonstrate how combining proven MTBM technology with the expertise of the teams enables reliable results, even in complex geological conditions.
