Noosa Main Beach Resilience
Noosa Council is undertaking a new project to design a future replacement of the Noosa Main Beach seawall.
The current seawall is over 50 years old (pictured, right, during construction) and was not designed or constructed to the standard needed to continue withstanding weather events that are going to worsen over time due to climate change.
A compromised seawall significantly reduces the resilience of Noosa Main Beach foreshore to withstand expected rises in sea levels and storm tides.
The new design will improve the seawall’s strength to boost the precinct’s resilience to natural disasters and rising sea levels due to climate change.
This project is for the design phase only. Construction will rely on the availability of funding.
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Background and FAQs
What is a seawall?
A seawall is a structure that separates land and water, designed to prevent coastal erosion and other damage from wave action and storm tide inundation.
Why is a seawall needed?
The existing Noosa Main Beach seawall is over 50 years old and technical reviews show the wall is degrading at a rate of three percent per year due to wear and tear and less-than-ideal rock choice. The movement of the rocks over time has also significantly reduced the resilience of the Noosa Main Beach foreshore.
Historical image of the Main Beach seawall courtesy of Heritage Noosa.
How can rock in a seawall deteriorate?
Rock naturally degrades over time depending on the type of rock and the environment. The rocks in the Noosa Main Beach seawall started at 2.75 tonnes each but now weigh an average of 600kg - less than a quarter of their original weight. The use of basalt as the predominate rock has been a factor in the wall’s breakdown.
Other key issues include:
- wave pounding – every wave creates tiny chips and cracks that eventually break the rock apart.
- salt water attack – salt water crystals form and widen existing cracks
- rock-on-rock grinding
- chemical breakdown from salt water reacting with iron-rich minerals in basalt.
Why does rock size and condition matter?
Seawalls are designed to absorb and deflect wave energy to protect the coastline. Smaller, smoother rocks cannot absorb wave energy as well as larger, angular ones.
The deterioration of the existing seawall is a substantial risk during future severe weather events so early intervention is vital.
Is the Sand Recycling System staying?
Sand is important to the resilience of the beach, and the Sand Recycling System has a key role in maintaining the beach and maintaining the structural integrity of the sea wall.
Council is looking at options to enhance, not replace, the current system, with the aim to maximise how we use what is already in place.
What is not included in the design?
The scope of this project is limited to redesigning the seawall to improve resilience.
Issues outside the scope include car parking and traffic management. Other areas of the beach, such as the groynes, are also not part of this project.
When will construction of the new seawall start?
Noosa’s Main Beach is a drawcard for locals and tourists alike. Construction would ideally be timed to avoid the peak summer period.
Timing for construction will depend on Council securing funds from the Australian and Queensland governments after design is complete.
What section of the beach is part of these investigations?
The existing seawall alignment runs along the Main Beach Boardwalk, with the seawall largely invisible beneath the sand. The design will consider this area along with the adjoining section of beach.
When will the community hear more about the project?
We encourage everyone to register for project updates so they can receive information about what is happening and know about future community events about the project.
The previous Community Information Sessions about the resilience project provided an opportunity for the community to have their say and hear firsthand about the project.
Information Sessions Summary(PDF, 279KB)
Historical images of the seawall
Images courtesy of Heritage Noosa.