Our beaches are always changing due to natural coastal processes and weather patterns. Erosion can impact beachfront infrastructure and properties. We install and maintain coastal protection structures to ensure our coastal infrastructure is protected from coastal erosion and wave action.
Seawalls are constructed along our coastline to protect coastal infrastructure from erosion.
On the Gold Coast they are made of large boulders buried under the sand. They remain buried during periods of calm weather but can be exposed during storms.
There are currently 14 kilometres of public urban shoreline and 9 kilometres of private urban property that need seawall protection.
We have a program that prioritises public seawalls for construction, renewal and recertification. The program includes:
- renew and recertify existing seawall
- construct new seawalls to join individual seawalls together and provide total coastline protection
- investigate older seawalls (called peel backs) to check their condition (saving $18.9 million in renewal costs).
Seawalls must be constructed along an approved alignment called the A-line. This alignment was established by the Queensland Government following severe storm erosion in the 1960s and 1970s.
The location of the A-line is defined by several factors, including the presence of existing walls and ensuring a smooth line along the foreshore.
Peel back projects
To check the condition of existing seawalls we excavate the sand that covers them. 'Peeling back' the sand allows engineers to assess the condition of existing seawalls and identify areas for maintenance. Recent peel back projects include Burleigh Heads and Rainbow Bay.
Constructing and maintaining a seawall for a private property is the responsibility of the property owner. Development regulations for beachfront properties are outlined in our City Plan.
Our City Plan and Land Development Guidelines ensure that foreshore seawalls are constructed to a standard design.
Before any development or redevelopment of a beachfront property can begin, including a material change of use, a seawall is required under the City Plan. A development application for construction and certification of the seawall must be submitted and approved.
How to build a private seawall(PDF, 856KB)
Groynes are low walls or barriers built out from a beach to reduce coastal erosion. Projects are undertaken to maintain and improve their function.
Two groynes were constructed at Kirra Point and Miles Street to reduce coastal erosion along the southern beaches in 1972.
In 1996, 30 metres of Kirra Groyne was removed to help with the movement of increased sand produced from the Tweed River Entrance Sand Bypass Project.
Kirra Groyne was returned to its original length of 180 metres to enable improve movement of sand along southern Gold Coast beaches. The work was carried out in 2013 as part of our management of Gold Coast foreshores outlined in our Ocean Beaches Strategy.
This project was undertaken in partnership with the Griffith Centre for Coastal Management to share information about construction methods, testing and certification, and coastal engineering issues.
Training walls are constructed to stabilise our creek entrances at coastal inlets to maintain one position along the coastline. Keeping them in one place improves navigation and safety for vessels, flood management, erosion and water quality.
Training walls are located at:
- The Gold Coast Seaway (built 1986)
- Tallebudgera Creek (built 1976–1981)
- Currumbin Creek (built in 1980)
- The Tweed River Entrance (NSW) (built 1880s, extended 1964).
Two artificial reefs have been constructed on the Gold Coast – at Palm Beach and Narrowneck. They buffer the coastline from the impact of waves.
Palm Beach Shoreline Project
Palm Beach is a four-kilometre stretch of southern coastline located between Currumbin and Tallebudgera Creeks. Exposure to high wave energy caused by southerly swells moving around Currumbin Rock has caused erosion over many years.
After extensive research, we chose a combination of sand nourishment and constructing a uniquely designed artificial reef to protect the shoreline.
In 2017, more than 470,000 cubic metres of clean sand was delivered along the shores of Palm Beach. The sand was a buffer against coastal erosion ahead of the construction of the Palm Beach Artificial Reef.
Palm Beach Artificial Reef
The artificial reef was built in 2019 at a cost of $18 million. It is approximately 270 metres offshore from Nineteenth Avenue between the beach and the existing natural reef.
The artificial reef works by influencing the surrounding waves and currents to promote a long-term increase in sand along vulnerable sections of the Palm Beach coastline. The dimensions are 160 metres long, 80 metres wide and 1.5 metres below the average water level and its highest point.
60,000 tonnes of basalt and greenstone rock were loaded onto barges in Brisbane and transported to Palm Beach. A specialist marine construction vessel then moved the rocks into position using GPS technology.
We monitor the artificial reef to effectively manage this dynamic part of the coastline. There has been a sustained increase in beach width and a large increase in marine sea life around the structure.
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The Narrowneck area has a history of serious erosion, especially from storms. In 1999, Narrowneck Reef was built to protect the vulnerable, exposed and narrow stretch of foreshore.
In 2018, a renewal project extended the life of the artificial reef. An additional 84 mega geotextile sandbags were installed around the existing structure using a specialised vessel. Minor changes to the shape of the renewed reef based on physical modelling from the Queensland Government Hydraulics Laboratory. Two yellow navigation buoys next to the reef were also installed to prevent damage from anchoring vessels.
We monitor the reef to ensure it continues to provide coastal protection. Monitoring shows that the reef has increased the beach's resilience against impact from storms and ocean swells.
Watch how the containers were placed on the sea floor in this video.