Coastal erosion is a global challenge threatening shorelines and communities worldwide. The Living Speed Bumps concept, developed by International Coastal Management (ICM), is a transformative approach to coastal resilience. It offers a sustainable alternative to traditional hard engineering methods, focusing on slowing sand movement while working with natural processes rather than against them. This soft-engineering methodology strikes a delicate balance between protecting coastlines and preserving the natural flow of sand, delivering adaptable and sustainable solutions for vulnerable beaches.
What Are Living Speed Bumps?
The Living Speed Bumps approach refers to strategically placed coastal features designed to reduce the speed of local longshore sand transport and retain sand for longer periods, allowing dunes and beaches to stabilise without downdrift impacts. Unlike contemporary engineering solutions like breakwaters and groynes that disrupt natural processes, living speed bumps slow sand movement while maintaining its fluidity, enabling natural ecosystems to adapt and thrive.
This concept is implemented through two complementary components:
Onshore Speed Bumps: Structures like artificial headlands or low/short by-passable berms
Offshore Speed Bumps: Submerged reefs or breakwaters placed offshore to reduce wave energy and promote sand retention in the nearshore zone
While some coastlines may benefit from a single component, such as a series of onshore speed bumps or a standalone offshore speed bump, others may require both elements working in tandem. Determining the best solution for a site requires the expertise of a specialised coastal engineering team. Our tailored approach ensures that each project aligns with local environmental conditions and community needs, creating a dynamic solution that protects coastlines while supporting their natural evolution.
What is Coastal Resilience?
Coastal resilience is the capacity of coastal communities, ecosystems, and infrastructure to adapt to, withstand, recover from, and thrive despite challenges such as coastal erosion, storm surges, sea-level rise, and climate change.
At its core, resilience means 'the ability to return quickly to a previous good condition after a problem or negative change'. In a coastal context, resilience can be assessed across various interconnected areas, including:
Physical Shoreline
Environmental Health
Community Wellbeing
Financial Viability
Regulatory Compliance
Each of these factors plays a critical role in shaping resilient coastal solutions. From a physical perspective, coastlines are inherently dynamic and often display natural resilience. This is evident on most sandy coastlines, where the ‘beach erosion’ and ‘accretion’ pattern (the dotted red line) happens cyclically.
During storm seasons, waves break up into the swash zone and erode the dune system. This sand is washed out into the storm bars which help then to reduce further erosion by breaking the waves. During calmer conditions, low wave energy ‘pushes’ the storm bar back into the swash zone, and wind helps to push dry sand back up into the dunes. Typically, new sand makes its way into the system to replace sand that also might have been lost.
A Changing Environment
Changes occur along our coastlines, it is inevitable, the coastal environment is highly dynamic. Some of these are due to natural changes and many are due to human influenced changes. If one of these conditions changes the balance, resilience potential will be disrupted.
Examples include:
Top of beach: the dunes are removed or built on
Bottom of beach: disruptive offshore structures
Sediment supply: blocked river previously supplying sand to a site or diminishing coral reef which previously provided sand to a site
The Coastal Resilience Framework
Building coastal resilience requires a comprehensive approach that addresses three critical components: the Top of Beach, the Bottom of Beach, and the Sediment Supply. The Top of Beach focuses on protecting and restoring dunes and other dry beach areas that act as the first line of defence against erosion and storm surges. The Bottom of Beach ensures the stability of the nearshore zone which includes the subtidal and intertidal areas that dissipate wave energy and support marine ecosystems. Finally, Sediment Supply involves managing sand sources, minimising disruptions, and promoting balanced sediment movement to sustain the beach system.
By integrating solutions that improve all three factors while allowing natural processes to thrive, this framework lays the foundation for building coastal resilience. It is a holistic, sustainable approach that prioritises long-term adaptation, environmental health, and community protection. This methodology reflects decades of ICM research and practical experience, offering a proven pathway for resilient and thriving coastlines.
Working in Nature vs. Working With Nature
Coastal engineering has undergone a significant evolution over the years, moving from approaches that block natural processes to those that embrace and work with them. Understanding this transition is key to creating sustainable coastal resilience solutions today.
The Evolution of Coastal Engineering
Most coastal solutions are heavily engineered. This is because coastal engineering is derived from civil engineering, and solutions were traditionally incorporated into coastal ports and harbours. These structures required keeping natural processes out (or to a minimum).
Waves and moving sand bars within a harbour or marina is not ideal. In fact, it can be dangerous, especially when loading and unloading goods. So, for improved functionality and trade potential, harbours were designed to be unnaturally calm under even the most significant storm events. Requiring large, hard engineering barriers to avoid the natural processes. This was fundamentally an ‘avoid’ approach.
Adapting for Beachfront Communities
As the popularity of beachfront living increased, the 'change' approach emerged. Engineers developed strategies and structures to alter natural processes, reducing erosion to protect properties and infrastructure. This phase prioritised human needs over the natural environment.
Transitioning to ‘Working With Nature’
The modern era of coastal engineering introduced a ‘working with nature’ or 'reduce' approach. Rather than avoid or change natural processes, it aims to ‘reduce’ and slow down the process to retain beaches for extended periods of time.
This approach was pioneered on the Gold Coast in the 1980’s by our Founder Angus Jackson, with the introduction of coastal solutions such as Nearshore Nourishment, which strategically places sand to create ‘designer sand banks’ that can nourish the beach slowly with natural cycles.
The ‘reduce’ approach focused on creating ‘speed bumps’ in the coastal zone, which led to the development of multipurpose artificial reefs (another concept pioneered on the Gold Coast with Angus Jackson). The development of the sand bypassing technology then allowed the Gold Coast to address the bottom of the beach, the sediment supply which led to the stabilisation of the top of the beach where significant coastal dune systems were developed, monitored and managed over the past few decades.
An Example
Below in an example of the ‘avoid’ approach (by others) with a significant, emergent breakwater vs. the ‘reduce’ approach by ICM on the same coastline, in the UAE. The submerged living speed bump allowed natural processes to occur at the site while maintaining a stable beach for 8 years (as per the contract agreement).
The Living Speed Bumps Design Philosophy
At its core, the Living Speed Bumps methodology prioritises:
Working With Nature: Slowing natural processes rather than stopping them, allowing sand to move but at a controlled pace that reduces erosion.
Soft Solutions: Favouring flexible, low-impact designs over rigid infrastructure to ensure harmony with coastal ecosystems.
Adaptability: Designing systems that evolve or can be adapted to changing environmental conditions, such as rising sea levels and shifting wave patterns.
Scalability: Tailoring solutions to fit local conditions and expanding them as necessary to address larger areas of coastline.
Proven Applications of Living Speed Bumps
The Living Speed Bumps concept is not theoretical - it has been successfully implemented in several key projects by ICM around the world. Each project demonstrates the flexibility and effectiveness of this approach in different coastal contexts:
1. Narrowneck Reef, Gold Coast, Australia
Onshore Speed Bump: An existing artificial headland.
Offshore Speed Bump: The Narrowneck artificial reef, designed to reduce wave energy and retain sand while creating a habitat for marine life.
Impact: The project enhanced sand retention along the shoreline, improved surfing conditions, and supported biodiversity.
2. Maroochydore, Queensland, Australia
Onshore Speed Bumps: Low, ‘soft’ berms were installed to stabilise sand flow and protect the beach from erosion.
Impact: Sand and waves naturally pass over the berms to maintain natural processes along the beach over the ‘speed bumps’ while reducing beach erosion.
3. United Arab Emirates: Submerged Rock Reef Breakwater
Offshore Speed Bump: A submerged rock reef breakwater was constructed to reduce wave energy and encourage sand deposition.
Impact: The breakwater successfully stabilised the coastline, providing a sustainable solution for managing erosion while preserving natural sand movement.
4. United Arab Emirates: Offshore geotextile reef and low crested groynes
Offshore Speed Bump: A geotextile reef was installed offshore to reduce wave energy and promote sand retention in the nearshore zone.
Onshore Speed Bumps: Low geotextile groynes were implemented along the coastline to complement the reef, managing sand movement effectively.
Impact: This combined approach created a more stable coastline and enhanced long-term resilience against erosion.
Living Speed Bumps: The Future. Oceanside, CA
ICM’s innovative Living Speed Bumps concept is now being implemented in Oceanside, California, as part of our winning proposal for the Re:Beach Design Competition launched by the city and GHD.
The project includes:
Onshore Artificial Headlands: Located at Tyson Street Park and Wisconsin Avenue, these structures act as speed bumps to slow sand flow along the top of the beach, helping stabilise sand and create new green spaces for community use.
Offshore Artificial Reef: Positioned between the headlands, this reef reduces wave energy, supports sand retention in the nearshore zone, fosters new marine habitats, and can enhance surf amenity in the reef’s vicinity.
The design builds on proven methodologies from ICM’s work on the Gold Coast and other locations, tailored to Oceanside’s unique coastal conditions. Public engagement played a critical role, with community input emphasising the importance of sand retention, recreational space, and protecting surfing conditions.
As a dynamic and scalable solution, Living Speed Bumps offer Oceanside a practical way to reduce erosion while setting a global precedent for innovative coastal resilience.
The Oceanside project is a pilot project and will be heavily monitored in the lead up to the implementation, during and after construction to ensure that the outcomes are met and inform any future decisions or projects along the California coastline.
Why Choose Living Speed Bumps?
The Living Speed Bumps approach offers several advantages over contemporary coastal protection methods:
Longevity: By working with natural processes, this concept minimises environmental disruption and can enhance ecosystem health.
Cost-Effectiveness: ‘Soft’ or low’ solutions are often more affordable than large, rigid infrastructure, making them ideal for resource-limited settings. Note that with lower capital costs, maintenance programs should be in place to achieve longevity
Flexibility: Living Speed Bumps can be tailored to suit diverse coastal environments and expanded as needed. The choice of materials, whether geotextile, rock, basalt, or even oyster-based structures, depends on the site’s unique conditions and is guided by ICM’s engineering expertise to ensure maximum effectiveness.
Community Benefits: By preserving beaches, improving accessibility, and enhancing recreational opportunities, these solutions strengthen community connections to the coast while addressing pressing erosion challenges.
Environmental Benefits: Living Speed Bumps encourage biodiversity by creating habitats for marine and coastal species. They promote natural sediment movement and retention, and can integrate nature-based solutions.
This adaptable and sustainable approach makes Living Speed Bumps an innovative choice for building resilient coastlines.
Challenges and Adaptations
While the Living Speed Bumps methodology has proven effective, each project presents unique challenges. Key considerations include:
Environmental Sensitivities: Ensuring that designs support local ecosystems and species
Balancing Competing Needs: Managing trade-offs between sand retention, surfing conditions, and public access, capital costs vs. maintenance costs
Long-Term Monitoring: Establishing robust post-construction monitoring programs to assess effectiveness and make data-driven adjustments.
ICM’s extensive experience allows for adaptive management, ensuring that solutions remain effective in the face of dynamic coastal processes.
A Vision for Coastal Resilience
Living Speed Bumps represent a transformative approach to coastal resilience, offering an alternative to contemporary engineering methods. By slowing natural processes rather than changing/blocking them, this methodology provides a more harmonious balance between protection, adaptation, and environmental preservation.
As climate change intensifies and coastal erosion accelerates, the need for innovative, solutions like Living Speed Bumps has never been greater. From the Gold Coast to Oceanside, ICM continues to lead the way in developing and implementing cutting-edge designs that protect shorelines and empower communities.
Interested in learning more about Living Speed Bumps or collaborating on a coastal resilience project? Contact us today to explore tailored solutions for your coastline.