Five minutes with Calloway Precast: what is a seawall, and what does one cost?
Calloway Precast is one of our industry partners. Project Coordinator Sarah Lindqvist put some questions to General Manager Trent Calloway.
What is a seawall?
A retaining wall on the sea side of whatever is being protected, usually a road or a house. It takes the wave energy so the land behind does not have to.
Is that what is proposed for Kings Beach?
Not entirely. On a normal seawall most of the design effort goes into the sea face. At Kings Beach the sea face is conventional and the main load comes from the sand side. Strandline Coastal Engineering is responsible for the design. Calloway would manufacture the precast units.
What does a seawall cost per metre?
It depends on height, footings, distance to site and crane access. The proposal's $47.2 million over about 400 metres works out at roughly $118,000 a metre, but that figure includes design, approvals and ten years of monitoring and maintenance, so it is not comparable with other projects. Calloway would welcome the opportunity to quote.
How long does a seawall last?
A design life of 50 years is a normal target if the wall is built to specification and maintained. Maintenance is the part that is most often underfunded.
Are there any concerns about access?
The stairs. I would want to walk the track with the engineers.
Partners have no role in, and no influence over, technical findings. See DKB-POL-006.
The Kings Beach Salt Runoff Containment Proposal is a proposal to build a 6 metre concrete wall between the sand and the sea at Kings Beach, Broken Head, NSW, to stop salt reaching the ocean. It has not been approved and no works are scheduled.