On the Gold Coast, coastal dunes play a vital role in building natural defences against erosion and storms, creating a dynamic landscape where urban development and natural beauty coexist. These sand dunes not only enhance the region’s coastal resilience but also provide essential protection for the shoreline.
International Coastal Management (ICM) has been a leader in implementing nature-based solutions that restore and strengthen coastal dunes, ensuring a sustainable balance between development and the coastal environment. Read on to learn all about sand dunes, how they are formed, and their role in resilience.
What Are Coastal Dunes?
Coastal dunes are naturally occurring formations along the shoreline, consisting of windblown sand that accumulates to create protective barriers. Dunes are essential for maintaining coastal resilience by acting as a buffer between the land and sea. They can help absorb the energy of storms, reduce coastal erosion, and protect inland areas from flooding - but they're not a standalone solution.
Why Are Sand Dunes Important?
They are vital to sand management because they offer long-term benefits for protecting the shoreline.
Their ability to absorb the impact of storms and high tides means that they can help reduce the frequency and severity of beach erosion, preserving the coastline and protecting communities.
Well-maintained dunes also build biodiversity by providing habitats for plants and animals.
How Are Coastal Dunes Formed on a Coast?
Coastal sand dunes form when waves move sand onto the beach, and strong winds (above 15-20 knots) blow the sand further inland. This process, known as aeolian transport, deposits sand onto dunes.
As the dunes grow, vegetation helps trap the sand, stabilising the dunes and preventing further inland movement. The primary dunes protect the coast, while secondary dunes, located further inland, develop with more mature vegetation and are less affected by erosion.
While dunes act as natural barriers, they are not standalone solutions to coastal erosion. Their stability and effectiveness depend on the broader dynamics of the coastal system. Successful dune management must also consider the Top of Beach (dunes and vegetation), Bottom of Beach (nearshore stability), and Sediment Supply (sand movement and sources). Adding dunes alone may not suffice if other critical factors are overlooked.
How do Sand Dunes Prevent Coastal Erosion?
The natural exchange of sand between the sea and the dunes dictates the health of our coastlines. Mild conditions nourish the beach, while storms may carve away at the landscape, pushing sand offshore, creating protective sandbars. Dunes and their vegetation help mitigate this erosion, absorbing wave energy and trapping windblown sand to maintain the delicate balance of the coastal system.
However, dunes are only part of the solution. Building sand dunes and vegetation without addressing underlying issues, such as disrupted sediment supply or unstable nearshore zones, can result in limited effectiveness. Our Coastal Resilience Framework, developed over decades of coastal engineering in Australia and globally, emphasises assessing the Top of Beach, Bottom of Beach, and Sediment Supply to develop comprehensive, sustainable coastal solutions that ensure dunes remain functional and effective over the long term.
The Gold Coast: A Model for Sand Dune Management
In the 1960s, the erosion crisis on the Gold Coast stripped dunes of vegetation, leaving coastal properties exposed and vulnerable. In response, our founder, Angus Jackson,
working at the council at the time, introduced a transformative approach to sand dune management. By integrating beach nourishment, dune stabilisation, fencing, and vegetation planting, Jackson established a framework that has become synonymous with effective coastal management.
This innovative strategy turned the Gold Coast into an internationally recognised model for coastal sand dune management, showcasing the power of natural defences in protecting urban beaches.
Key Innovations in Dune Management on the Gold Coast
Angus Jackson's contributions during his time as Gold Coast's Director of Beaches and Waterways, included significant advances in policy and practical implementation. His efforts included:
Extensive fencing and aerial fertilising trials to stabilise nourished dunes in non-urban areas.
Policies for seawall construction and dune management in urban areas.
Provisions that all excess sand excavated within 500m of the seawall line was to be placed on the beach and stabilised (previously sold for construction purposes).
These measures set the foundation for the Gold Coast’s enduring coastal resilience.
The Gold Coast Coastal Planning Policies
The policies introduced in the 1980s and expanded in 1990 became foundational for coastal resilience on the Gold Coast:
Policy 7: Foreshore Rock Wall Design and Construction defined seawall construction standards and requirements for dune stabilisation.
Policy 15: Management of Coastal Dune Areas focused on preserving and enhancing dune systems for environmental, visual, and public access benefits. This policy outlined the following key principles for dune management:
Stabilising dunes to minimise impacts of cyclonic winds on the natural and built environment adjacent to the active frontal dune area.
Preventing sand losses from wind erosion.
Establishing a sustainable habitat and wildlife corridors.
Reinforcing the visual amenity with appropriate vegetation and public education.
Facilitating safe public access through public land within dunal areas by defining access ways and public areas that can be maintained to a high standard with minimal impact on natural systems.
Considering the privacy requirements of beachfront residents.
Results and Long-Term Impact
These policies were very effective and resulted in not only construction of an almost continuous terminal seawall but also facilitated the importation of over 1.5 million cubic metres of sand to form a substantial dune buffer. These measures transformed the Gold Coast into a resilient and visually stunning coastline, proving that thoughtful dune management can simultaneously protect properties, preserve ecosystems, and enhance public enjoyment.
The Gold Coast Now: Seawalls + Dunes
The Gold Coast’s policies have set a benchmark for coastal development. A central aspect of these policies is the requirement for new beachfront developments to rebuild existing seawalls if they are not up to standard or have degraded. These seawalls must meet Council’s strict design standards and align with the adopted foreshore seawall line, which follows the long-term primary dune alignment.
Additionally, properties concerned about erosion or the integrity of their existing seawalls can proactively rebuild these structures, accompanied by dune stabilisation measures. By ensuring that seawalls are complemented with well-maintained dune systems, these policies enhance the stability of the foreshore, reinforce the natural protection offered by dunes, and preserve the visual and ecological value of the coastline. This holistic approach highlights the interconnected nature of seawalls, dune ecosystems, and sediment management in achieving long-term coastal resilience.
ICM specialises in designing and constructing seawalls, dune stabilisation and vegetation plans that meet Gold Coast City Council standards. With decades of experience, we provide tailored solutions, ensuring seamless navigation through regulatory approvals to protect your beachfront investment while enhancing resilience. |
Urban Dunes and Coastal Resilience
Coastal dunes are not just natural defenses; they are dynamic systems that can adapt to sea-level rise and evolving coastal conditions. On the Gold Coast, we've demonstrated how dunes can coexist with urban landscapes, blending erosion protection with enhanced livability.
Looking ahead, urban dunes will play a pivotal role in climate change adaptation, offering a flexible buffer against rising seas and storm surges while buying critical time for emergency response. These strategies provide a blueprint for building resilient coastal cities worldwide, ensuring that natural defences work in harmony with urban development.
Sand Dune Restoration
Dunes are naturally dynamic systems, continually shifting and evolving in response to wave energy, storms and wind. The goal is to enhance resilience by reducing severity of erosion and introducing systems that help dunes rebuild and adapt over time.
There is no one-size-fits-all solution, each coastline requires a tailored approach, guided by engineering expertise to identify the most effective strategies. At ICM, we specialise in developing dune systems that protect coastlines while working with natural processes.
Here are some potential solutions:
The Top of the Beach: The dry beach area, where dunes, natural or engineered, retain sand and stabilise the coastline. Depending on the location, different solutions such as geotextile sand containers, coir logs, and dune fencing can enhance sand retention and protect fragile ecosystems. Dunes can also be developed to bury terminal seawalls.
The Bottom of The Beach: Below the low-tide active zone, Nearshore Nourishment and Multi Purpose Artificial Reefs are two solutions that can dissipate wave energy and reduce storm impacts dependent on the site. These measures can reduce erosion effects on dune systems while maintaining natural coastal dynamics.
Sediment Supply: Sustainable sediment supply is crucial for long-term success. Options such as sand bypassing systems, backpassing, and reusing locally sourced materials can help dunes remain robust and resilient over time.
Our expertise, honed over decades on the Gold Coast, showcases how engineering solutions can work with nature, creating thriving, resilient coastlines that stand as global models for sustainable coastal management.
How does Dune Fencing Help the Development of Sand Dunes?
Dune fencing is a simple yet effective method to protect and restore coastal dunes. These fences are strategically placed to trap windblown sand, helping to build and stabilise dunes naturally. By reducing foot traffic they protect fragile vegetation that anchors the dunes, and when combined with other restoration efforts, dune fencing supports long-term coastal resilience and enhances ecosystem health.
Why Can’t You Walk on Sand Dunes?
Although coastal sand dunes may appear resilient, walking on them can severely damage the delicate vegetation that stabilises the sand. Without this vegetation, the dunes become vulnerable to wind erosion, and the sand can be lost inland or carried away by storms. This is why it’s essential to avoid walking on dunes and to use designated pathways to protect these vital coastal formations.
Want to Develop Coastal Resilience Strategies for your Coastline or Property?
Schedule a free 15-minute consultation with one of our experts. We’ll discuss your needs and explore how ICM can provide tailored solutions for your project.
Acknowledgments
We extend our gratitude to the City of Gold Coast and all those who have contributed to shaping its shores - from past councils to consultants and contractors - who have played a pivotal role in maintaining and protecting the coastline through innovative coastal sand dune management.