On the Gold Coast, coastal dunes play a vital role in building natural defenses against erosion and storms, creating a dynamic landscape where urban development and natural beauty coexist. These coastal 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 these coastal dunes, ensuring a sustainable balance between development and the coastal environment.
Note: this post is a summary of the Technical Article by Angus Jackson and Zack Lindenberg
What Are Coastal Dunes?
Coastal dunes are naturally occurring formations along the shoreline, consisting of windblown sand that accumulates to create protective barriers. These dunes are essential for maintaining coastal resilience by acting as a buffer between the land and sea. They help absorb the energy of storms, reduce erosion, and protect inland areas from flooding.
Why Are Coastal Sand Dunes Important?
Coastal dunes are vital to coastal sand dune 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 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.
This natural process is essential for maintaining coastal resilience and protecting beaches.
How do Sand Dunes Prevent Coastal Erosion?
Dunes are more than just picturesque landscapes; they're the backbone of our beaches. 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 bars.
Yet, it's the dunes and their vegetation that mitigate this erosion, absorbing the ocean's energy and trapping windblown sand. It's a delicate balance, one we've learned to harness and respect through our work on the Gold Coast.
The Role of Gold Coast Sand Dunes in Coastal Management and Resilience
ICM has a long-standing commitment to sand dune management on the Gold Coast, a critical component of the region's coastal defense system. Since the 1970s, Gold Coast sand dunes have played a pivotal role in protecting our beaches, evolving alongside innovative coastal management practices. Today, the integration of these sand dune systems into broader coastal resilience strategies showcases their effectiveness in safeguarding against erosion, storms, and rising sea levels.
Through a combination of natural defenses and urbanisation, the Gold Coast coastal management approach has become a model of sustainability, ensuring that these coastal dunes continue to protect the region’s iconic beaches while balancing the needs of development and conservation.
"The legacy of the Gold Coast's beach nourishment began with Sam Smith's daring ventures in 1973. As the second coastal engineer for the City of Gold Coast, I inherited a treasure trove of knowledge, pivotal to our second wave of innovative coastal works. Over the decades which led to the development of ICM, we continued to expand this knowledge base, protecting our cherished shores through nature based implementation, monitoring and technique development." - Angus Jackson, Founder of ICM
The Gold Coast - a Model for Coastal Sand Dune Management
In the 1960s, the erosion crisis on the Gold Coast led to innovative approaches in sand dune management. The dunes were stripped of vegetation, leaving coastal properties vulnerable. In response, our founder, Angus Jackson, working at the council at the time, introduced a combination of beach nourishment and dune stabilisation, including the use of dune fencing and vegetation planting, which became the hallmark of Gold Coast coastal management.
This innovative approach turned the Gold Coast into a model for coastal sand dune management, demonstrating the power of natural defenses in protecting urban beaches.
An extract from the technical report:
"Extensive fencing and arial fertilising trials of the nourished dunes was carried out during my time as the Gold Coast's Director of Beaches and Waterways in non urban areas.
To extend this into areas with private oceanfront properties (urban areas), we developed a policy in 1985 for seawall construction and dune management (Jackson 1985). This policy recognised the need for dunes to seaward of the boulder seawall.
This policy also recognised the value of a good beach to beachfront properties and included a provision that all excess sand excavated within 500m of the seawall line was to be placed on the beach and stabilised (previously sand excavated for basements was sold for construction)."
"This policy was very effective and resulted in not only construction of an almost continuous terminal seawall but also importation of over 1.5Mm3 of sand to form a dune buffer seaward of the new walls.
This policy was expanded into 2 complementary policies (7 and 15) in 1990 to be part of the Gold Coast's Town Plan.
Both these policies provide details on dune management with fences and native vegetation, while policy #15 explains the nature and importance of dunes:
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 corridor for wildlife.
reinforcing the visual amenity of the City’s beaches by:
using appropriate vegetation in dunal areas; and
education and promotion of good landscape design principles in establishing new vegetation in urban areas in, and adjacent to, dunal areas.
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 visual amenity and privacy requirements of beachfront residents."
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.
Urban Dunes in Coastal City Planning
The world is urbanising, and the coastlines are no exception. Our work on the Gold Coast has proven that dunes can coexist with cityscapes, offering a multitude of benefits, from erosion protection to enhancing livability. As we look ahead, urban dunes will be pivotal in our climate change adaptation strategies. Well-vegetated dunes offer a dynamic defense, adapting to sea-level rise and providing time – the most precious resource in emergency management.
Embracing Coastal Dunes for Coastal Resilience
The evidence is clear, coastal dunes can adapt to and even outpace sea-level rise. They're natural fortifications that can grow with the challenges they face. Our approach on the Gold Coast – blending dune restoration with nature-based solutions – has mitigated significant sea-level rise impacts. As we navigate the future, the lessons we've learned here will be critical in fostering resilient coastal cities globally.
Dunes need to be part of a holistic resilience strategy
To properly address any coastline and improve the chance of building resilience there must be a multitude of factors take into consideration. However, when looking purely at the physical response there must be a three pronged approach, considering the following:
The Top of the Beach: this is the dry beach area which includes dunes (natural or manmade). There are various structures and strategies that can be implemented to improve short and long term sand retention potential in this zone.
The Bottom of The Beach: this is the area in the below low tide active zone (this area can be supported with actions like Nearshore Nourishment and Multi Purpose Artificial Reefs)
Sediment Supply: this is key to ongoing success and can be addressed in a variety of ways on a local and regional level (sand management plans may include physical interventions such as sand bypassing or sand backpassing systems as well as re-use of locally available material from an array of sources)
Want to develop coastal resilience strategies for your coastline or property?
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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.