Re: Waikawa Marina Extension Project Update – January 2021
Stage Two of Works Underway!
Stage two of works involves the construction of the breakwater – the breakwater forms the perimeter of the marina in the water, and will be constructed from steel piles driven into the seabed at 4m centers with precast-concrete panels ‘clipped’ onto the front. Its purpose is to protect the berths from wave action and storm events.
During the preliminary design process, it became apparent that a traditional rock breakwater was not going to be a feasible option due to the water depth of up to 16.5m in the outer parts of the marina. We considered several other options and by using computer and scale modelling, it became apparent that the fixed pile and panel breakwater was going to give the best result for marina users. This breakwater structure also has the added advantage of being more environmentally friendly; by having a small footprint on the seabed when compared to a traditional rock breakwater and also because the panels only going to -5m CD, this allows water and marine life to pass under the breakwater.
Our Breakwater Contractor, Tas Marine Construction (TMC), has arrived on site and are setting up ready to start piling works in early February. TMC won the contract to build the breakwater by competitive tender in late 2019. Through their tender submission, TMC demonstrated they had the skill and experience to build this type of breakwater. In their tender submission, TMC also proposed changes to the tender design to simplify the structure; we have worked with TMC and the designers, Burbury Consulting, to incorporate these changes.
The welding of the breakwater steel piles into 24m lengths has been underway at a local engineering workshop, HML Engineering, and the first deliveries of welded piles have been arriving on site.
Photo 1 – Welding of piles at engineering shop
Photo 2 – Welded piles arriving to site.
Further machinery and equipment has been arriving on site for the construction of the breakwater.
On completion of their site setup, our Breakwater Contractor will then start their piling works. The piling works will take approx. 4-6 months to complete and will be the main activity on site during this period. A local precast company will fabricate the concrete panel’s off-site ready to be trucked to site for installation.
Part of the contractor establishment, TMC have been developing construction management plans to ensure they minimise the impacts on the surrounding environment. The key environmental hazard from their construction will be the noise from the piling, this is both airborne and waterborne noise, we will use systems and best practices to reduce the effects of the piling noise, including training undertaken to help protect the marine mammals.
The breakwater installation works will take approx. 8 months to complete.
Construction Safety Zone
The majority of the breakwater installation works is from floating plant, this includes a large barge set up with a crane and piling equipment. A workboat will maneuver the barge into position and tow piles to the barge.
The Harbour Master has installed two yellow special navigation buoys to highlight the risk as you approach the site from the north. Our breakwater contractor will install further navigational aids as the piling works progress.
We ask that you do not enter the construction zone and maintain a minimum of 30m separation from any of the construction plant or installed works.Back to Waikawa North West