Artificial Reefs and Nearshore Nourishment on the Gold Coast: What the Monitoring Shows
- Aaron Salyer
- Sep 18, 2023
- 6 min read
Updated: Jun 3
The Gold Coast is one of Australia’s best-known examples of long-term coastal management. Its beaches support tourism, recreation, public infrastructure, private property and internationally recognised surf breaks. They also sit within a highly dynamic coastal system shaped by storms, waves, currents and longshore sand transport.
Managing this coastline has required more than one project or one type of coastal structure. Over several decades, the Gold Coast has used beach nourishment, nearshore nourishment, sand bypassing, dune management and artificial reefs as part of an adaptive coastal management strategy.
ICM’s experience on the Gold Coast draws on this long-term evidence base, including early nearshore nourishment trials, multi-purpose artificial reef design, beach monitoring and the use of nourishment to support both erosion management and coastal amenity. These initiatives were spearheaded by the efforts of ICM's founder Angus Jackson in the early 80's (as the Gold Coast City's Coastal Engineer) and subsequently by International Coastal Management (ICM).
Why the Gold Coast Needed a Long-Term Coastal Management Strategy
The Gold Coast experienced major erosion events during the 1950s, 1960s and 1970s. These events exposed the vulnerability of a developed coastline where beaches play a central role in recreation, tourism, public access and coastal protection.
Early beach nourishment campaigns helped demonstrate that adding sand to the system could improve beach width and buffer capacity. However, large-scale onshore nourishment could be costly, disruptive and difficult to maintain without a long-term sand management strategy.
This led to a more integrated approach. The focus shifted from reactive measures to proactive, long-term strategies. The idea was not just to combat erosion but to enhance the coastline's recreational and ecological value looking at more nature based solutions. This forward-thinking approach set the stage for innovations like artificial reefs, structures designed to promote sand accumulation and dissipate wave energy, reducing erosion.
A Pilot Approach
One of the strengths of the Gold Coast approach has been the use of piloting and monitoring to guide future works. With this proactive plan, the area became what could be called a full-scale coastal laboratory.
With each project, monitoring and feedback loops were set up so that real-world results could be used to guide future projects. Because of this commitment to solutions based on facts, the Gold Coast has become known around the world as a model for smart and flexible coastal management.
Key Gold Coast Projects and What They Show
A series of landmark projects paved the path of the Gold Coast's transformation:
The North Gold Coast Beach Protection Strategy
The North Gold Coast Beach Protection Strategy was a major coastal management program delivered between 1997 and 2001 to widen and protect the northern Gold Coast beaches. The strategy combined beach nourishment, completion of the boulder wall, ongoing maintenance nourishment and the construction of a nearshore artificial reef at Narrowneck.
The project is important because it shows how artificial reefs and nourishment can be planned together as part of an integrated coastal protection strategy. ICM managed key project elements including design studies, impact assessment, engineering design and implementation. The project also included physical and numerical modelling, environmental management planning and monitoring to assess performance over time.
Narrowneck Artificial Reef
Narrowneck Artificial Reef was designed as a multi-purpose artificial reef, with coastal protection and surf amenity objectives. The reef was constructed using geotextile sand containers, which were approximately 1/3 the cost of a rock reef construction. This cost-effective approach was consistent with the pilot nature of the project.
Long-term monitoring has shown geomorphological changes to littoral sand drift. This has caused a buildup of sand around the reef, helping to reduce erosion and offering added surf benefits on sandbanks.
The project remains an important reference point for multi-purpose artificial reef design because it shows how a reef can be designed to influence sand movement, reduce erosion risk and support surf amenity without fully blocking natural coastal processes.
Key Outcomes:
Demonstrated successful use of geotextile sandbags, offering cost-effective reef construction.
Induced geomorphological changes, leading to sand build-up around the reef.
Reduced coastal erosion and enhanced surfing conditions due to formed sandbanks.
Provided lessons that informed later artificial reef projects.
A 20-year scientific review of Narrowneck Reef found that the reef has had a localised influence on nearshore morphology and has helped maintain the beach in a more stable condition than before construction. The review also found that sand transport can occur both inshore and offshore of the reef, depending on wave conditions. This is important because it shows that a multi-purpose artificial reef can influence sediment movement without preventing sand from continuing through the coastal system.
Sand Bypassing Systems at the Nerang and Tweed Rivers
Sand bypassing has been central to the Gold Coast’s long-term sand management strategy. At tidal entrances such as the Nerang River and Tweed River, training walls and entrance works can interrupt natural longshore sand transport. Bypassing systems help move sand past these entrances so it can continue feeding downdrift beaches.
These systems also support navigation by managing sand accumulation near entrances and channels. On the southern Gold Coast, sand bypassing has also contributed to well-known surf outcomes, including the Superbank and South Stradbroke Island. These systems not only ensured uninterrupted sand delivery to nourish southern beaches but also played a pivotal role in mitigating erosion.
Key outcomes:
Supported the continuation of longshore sand transport past trained entrances.
Helped manage sand accumulation near navigation channels and entrances.
Improved navigational access
Provided a long-term sand supply mechanism for beaches.
Enhanced surf conditions at iconic spots like the Superbank and South Stradbroke Island.
Palm Beach Artificial Reef (PBAR)
Palm Beach Artificial Reef was completed in 2019 and was informed by lessons from Narrowneck Reef and previous nourishment works. The reef was designed to contribute to coastal protection while also supporting surf amenity where conditions allow.
Monitoring has shown the development of sandbank surf breaks around the reef, including waves associated with sand movement and reef influence. Surveys have also indicated that nourished sand has remained within the Palm Beach system, enhancing the coastal landscape and supporting its recreational potential.
Key Outcomes:
Used monitoring results from Narrowneck for informed design and implementation.
Wave Peel Tracking (WPT) indicated the development of desirable sandbank surf breaks around the reef.
Ongoing surveys showed retained nourished sand around the reef, indicating long-term effectiveness.
The 2017 Gold Coast Beach Nourishment Project (GCBNP)
The 2017 Gold Coast Beach Nourishment Project placed more than 3 million cubic metres of sand along vulnerable sections of the Gold Coast coastline. The project used nearshore nourishment to deliver large volumes efficiently, with sand placed offshore where waves and currents could move it through the active beach system over time.
At Palm Beach, survey results five years after implementation indicated that around 75% of the nourished sand remained within the system. This outcome is important because Palm Beach has historically been one of the Gold Coast’s more erosion-prone beaches.
The result reflects the value of combining nourishment, reef design and monitoring within a broader coastal management strategy. Rather than treating nourishment as a stand-alone campaign, the Gold Coast approach has used repeated monitoring and adaptive design to improve long-term performance.
This project was built on decades of research and development in the field of mass nourishment, led by Angus Jackson and ICM.
Key Outcomes:
Successfully added over 3 million cubic meters of sand to vulnerable beach sections.
Five-year post-implementation surveys revealed 75% of nourished sand at Palm Beach still within the system.
Proved the combined efficacy of nearshore nourishment and the Palm Beach reef, retaining sand even after significant storm events.
Key Lessons from the Gold Coast
The Gold Coast experience highlights several lessons for coastal managers considering nearshore nourishment, artificial reefs or integrated coastal protection strategies.
Monitoring is essential. Coastal works need to be assessed over time, not judged only by the immediate post-construction beach condition.
Nourishment and structures can work together. Artificial reefs can influence wave breaking, sediment pathways and local sand retention when designed for the right site.
Understand sand systems. Nearshore nourishment can be an effective way to work with nature - sand is placed where waves and currents can move it through the beach profile.
Surf amenity can be part of the design brief. On the Gold Coast, reef and nourishment projects have shown that coastal protection can also consider recreation outcomes.
There is no single solution for every beach. The best outcomes come from understanding the sediment budget, wave climate, community values, asset risk and long-term management objectives.
What This Means for Other Coastal Communities
The Gold Coast shows that coastal resilience is built over time. Nearshore nourishment, artificial reefs and sand bypassing are most effective when they are planned as part of a wider coastal management strategy and supported by monitoring.
For other coastal communities, the lesson is not to copy the Gold Coast exactly. Every site has different wave conditions, sand sources, coastal processes, environmental constraints, community values and asset risks. The value of the Gold Coast experience is that it shows how evidence, staged delivery and adaptive management can improve long-term outcomes.
ICM supports councils, agencies and coastal asset owners with feasibility studies, concept design, detailed design, approvals support, nourishment planning, artificial reef design and monitoring programs for complex coastal environments.
Acknowledgements
ICM acknowledges the City of Gold Coast and the many coastal managers, researchers, consultants and contractors who have contributed to the Gold Coast’s long-term coastal management program. The success of these projects reflects decades of monitoring, practical decision-making, design refinement and collaboration across government, industry and research partners.
