Roe Highway is part of a key road corridor in Western Australia that links the Kwinana Freeway to the Great Northern Highway, providing access to the Kewdale, Hazelmere and Canning Vale industrial areas. Prior to the construction of the interchange, Kalamunda Road was one of the last remaining signalised intersections on Roe Highway.

Completed in late 2021, this project involved the construction of a grade-separated interchange at the Roe Highway and Kalamunda Road intersection.

Main Roads WA engaged BG&E to design the relocation of Water Corporation’s major trunk and distribution mains affected by the works. The project required the relocation of five separate water mains and their associated complex multi-valve arrangement which included Pressure Reducing Valve (PRV) arrangement installations. Due to the importance of the PRV’s, they were designed to be above ground installations, housed in a specialised and secured Water Corporation managed building.

This project also included the detailed design and management of significant potential electrical fault touch voltages due to the close proximity of the Western Power’s transmission towers that were previously constructed without a continuous earth/fault wire.

As lead consultant, BG&E, worked closely with the overall project team, including specialist Water Corporation accredited Earth Potential Rise (EPR) electrical consultants, to determine agreed safe voltage mitigation measures to be implemented on the steel pipelines during construction and for Water Corporation’s permanent arrangements.

The water pipeline length and sizes consisted of three sizes of mild steel cement lined (MSCL) pipe:

• 900 metres of 1400 diameter.
• 1250 metres of 600 diameter.
• 400 metres of 300 diameter.