Client: Department of Transport

Construction Period: November 2018 – April 2019

Total Value: $3,560,000 + GST

This project included placement of new rock armour and repair of existing armour along a 600m long causeway along Jetty Road Bunbury. Over 31,200tne of rock was supplied and placed for the Department of Transport to strict standards and tolerances. This also included reclamation areas for a future multipurpose building and cul-der-sac turning area. A 500m long retaining wall was also constructed along the western revetment.

    The project included:

    • Supply and placement of 12,700tne class 1 (300-1000kg) rock to strict tolerances to provide an aesthetically pleasing finish;
    • Supply and placement of 2,250tne class 2 (60-300kg) rock;
    • Supply and placement of 11,600tne class 3 (10-60kg) rock;
    • Supply and placement of 4,000tne Run of quarry rock;
    • Supply and placement of 600tne Run of transition rock material;
    • Disposal of excess unsuitable spoil off site (over 3,300T of seabed mud and concrete waste);
    • Construction of 500m long limestone block wall with reinforced concrete footing and aggregate filled drainage trench along the western revetment. This included careful placement of rock amour against the finished wall;
    • Construction of reinforced concrete footings for future CCTV poles;
    • Repair of the boat harbour side of the causeway revetment using material from the existing revetment and imported rock material;
    • Removal of oversized rocks from the existing revetment, breaking to a suitable size and reusing;
    • Reconfiguration of the sea side causeway revetment using removed material from the existing revetment and imported rock material;
    • Reclamation for future multi-purpose building and cul-de-sac and northern interface between existing causeway revetment and spur groyne;
    • Earthworks to lower the causeway head by ~2m to allow the staged construction of the revetment armour work. This included excavation of seabed by up to 1.5m, sieving out unsuitable concrete and rubble from cut material so sandy material could be reused for backfill, staged placement of rock armour, and backfill of causeway head;
    • Removal and disposal of 250m of redundant asbestos water pipe;
    • Removal of redundant light poles;
    • Removal of 12No. existing timber jetty piles in the revetment using divers and underwater chainsaws;
    • Traffic management to allow 24/7 access to the finger jetties for boat pen owners. This was achieved via traffic management, use of spotters and gateman, establishing temporary parking areas, and communication with the boat pen owners;
    • Engaging an Ornithologist to remove nesting seagulls, eggs and hatchlings to allow the rock work to progress without harm to fauna;
    • Working in an environmentally sensitive area including provision for dolphin monitoring, water turbidity monitoring, contaminated soil testing, etc;
    • Working in an area that had to take into account tides and weather conditions to ensure the work was completed safely and avoid erosion of the works;
    • Providing an aesthetically pleasing rock revetment that was also well built to protect the foreshore.

    The project was effectively managed without environmental incident. All of the works were completed on time and on budget.