For the Collie River bridges, a variety of temporary works were required and applied in accordance with the necessary environmental permits and approvals. These included:

• A silt curtain to act as a protective barrier for the river and to prevent sediment, silt and soil entering the watercourse.
• A sediment fence to provide further protection for the river by retaining sediment, silt and soil while also allowing water to drain into the river, reducing the impact on aquatic fauna.
• Use of geofabric - a unique high-strength material specifically designed to stabilise soil and keep earth in place.
• Bulk-A-Bags: large, custom designed bags filled with clean aggregate to provide the necessary weight to keep the other works in place and act as a retaining wall for the work platform.

This detailed approach means that the water quality and fauna of the Collie River and the riverbanks’ slopes will remain well protected throughout construction and installation of the piles.

Once the necessary structures are in place, our team will methodically remove the backfill material, carefully lift out the bulk-a-bags, retrieve the geofabric and dismantle the sediment fence and silt curtain.

"It was a critical concern of ours to incorporate additional controls in the river front pad construction and amend the methodology to ensure minimal impact on the natural environment." said Alfred Abi Assy, Senior Project Engineer. "Slope stability and erosion protection were key objectives in the design of the temporary works and we are proud of the solution that was designed and implemented."