Erosion Mitigation Units (EMU): 2023 Victorian Premier’s Design Awards Jury Commendation – Product Design and Highly Commended – Circular Design and Sustainability

Industrial designer and founder of Melbourne studio Reef Design Lab, Alex Goad, has been designing and developing marine habitats since his honours year at Monash University. His MARS project – a system that provides a permanent structure for transplanting coral and protects habitats for other species – was the catalyst for starting the company, and it is now part of the permanent collection at both the NGV and the Museum of Modern Art in New York.

Over a decade ago, while he was still a student, Alex embarked on preliminary discussions with the City of Greater Geelong to design an underwater sculpture park in an area known as the Dell. The initial brief went through a series of evolutions, based largely on Alex’s foresight to create a hybrid between traditional engineering and art in a project that would serve as both a sculptural installation and a series of wave attenuators that would help protect and rebuild the region’s fragile marine ecology.

The result was the design, fabrication and placement of 46 organically-shaped, pre-cast erosion mitigation units (EMU) to form the Dell Eco Reef at Clifton Springs on the Bellarine Peninsula, a sustainable marine habitat restoration site that also provides a visually stunning and accessible snorkelling destination. The EMU project received a jury commendation at the 2023 Victorian Premier’s Design Awards in the Product Design category and its ongoing success is being monitored by Melbourne University’s National Centre for Coasts and Climate.

Image of Emu Project

Customised design based on ecological principles

There were a number of technically challenging elements to the design and fabrication process. Whereas many of Reef Design Lab’s projects utilise large format 3D printing and digital fabrication, the EMU design was customised and required a very specific mold that was both economical and sustainable. Using a low carbon concrete, replacing standard cement with an eco-bond cement mixture made with 30% fly ash, allowed the team to integrate recycled shells. Vibrating the mix brought the shell aggregate to the surface, which was then sandblasted to reveal the shell coating and provide more micro-surface complexity, forming a perfect substrate to attract species like oysters and mussels.

Having worked closely with ecologists for many years, Reef Design Lab has developed a strong understanding of what works. Research of the local marine environment was an integral element in the design. Despite Port Philip Bay having lost much of its natural shellfish reefs due to 2 centuries of trawling, Alex and his team studied existing rocky reefs to understand what occurs naturally. By surveying the area, looking at the types of habitats that exist and understanding the volume of water in rock pools, they could incorporate as many ecological design principles as possible into their EMU.

According to Alex, there are multiple benefits to designing in this way, allowing a human-made structure to replicate aspects of natural ecology and be sympathetic to the marine life, with gradual integration into the environment while acknowledging that the EMU was always going to be artificial structures.

The size and dimensions of the units also needed to be carefully considered to meet wave attenuation criteria and to create as much surface area as possible. They were designed to undulate – ‘like a rolling hill.’ Whereas in nature there may only be a single large rocky structure, when placed together, the EMU allows people to snorkel or swim between and through them with plenty of water flow surrounding the structures.

A project 10 years in the making

Despite the 10-year lead-up, intensive research and customising of the design, the EMU were manufactured within a few months. The formwork for the structures was built in-house in Reef Design Lab’s Mentone factory and the casting was done locally – all during the pandemic period.

‘Having our own manufacturing capabilities and being able to fabricate in-house is the best way for us to maintain design integrity and provide a greater surety of the structural success of each unit,’ Alex said.

Each EMU weighs approximately 1.6 tonne and is held in place using an earth anchor. They were easily installed in October 2022 using a simple barge and crane system in a single day. The EMU continue natural coastal processes while dampening the waves and protecting the area from erosion.

‘This project was a great example of collaboration with a client – the Geelong City Council – that helped us overcome every hurdle and was brave enough to do something a bit different,’ Alex commented.

‘In particular, collaborating with Ralph Roob, Geelong’s Head Coastal Engineer, gave us the opportunity to work closely on the aesthetic language used and create something special, an ecologically-inclusive, permanent coastal structure that is bio-protected by everything that grows on it,’ he added.

EMU as a template for the future of coastal preservation

Reef Design Lab recently installed similar EMU at Kingscote, Kangaroo Island to create a new snorkelling reef and the company is also working with Melbourne University on a US Government project to help protect coastal areas around US military bases.

‘People have always landscaped and gardens. In coastal environments, now is the time to landscape and create gardens underwater in a way that is ecologically productive,’ Alex remarked.

Positive outcomes

While winning awards and being recognised have been rewarding outcomes of the EMU project, Alex takes particular joy in the way the Dell Eco Reef has been embraced by scuba divers, snorkellers and the swimming community in the region. Although it is still a little too early to tell, the success of the project will be measured by the way it attracts colonies of fish and shellfish to return to the area. Stingrays are already harbouring under the EMU and thick mounds of seagrass growing around them points to structure stabilisation.

‘It’s so exciting to see a botanical garden in this inter-tidal zone and our vision coming to life,’ Alex remarked.

‘But the most rewarding part for me personally is the amount of coverage and positive feedback we have received and knowing that people are sharing our vision of what the future of coastal protection could look like,’ he added.

With so much negativity surrounding the impact of rising sea levels and climate change on marine environments, it is heartening to know that this site could be a template for what is to come. Studies being conducted by a team of marine scientists led by Dr Rebecca Morris over the next 5 years are covering a variety of aspects of the project, from conservation and erosion to the growth in numbers of fish. But Alex is quick to point out that this is just one small step in the fight towards protecting our coastal and marine scapes from issues that include CO2 emissions, invasive species and a lack of predators to balance the delicate ecology.

Receiving a jury commendation at the Victorian Premier’s Design Awards has given Alex and his team the opportunity to raise the profile of the long-term benefits of introducing human-made structures to help protect sensitive marine ecologies. They believe that the type of infrastructure that they design will become far more important in this era of climate change and represents the future of coastal protection

In addition to its Victorian Premier’s Design Awards jury commendation, EMU was also awarded gold at the Good Design Awards 2023 in the Product (Commercial and Industrial)category and was the Sustainable Design (Building Product) winner of the year 2023 at the Dezeen Awards.

Experience the EMO for yourself

According to Alex, the best time to swim or snorkel among the EMU modules is at high tide, when the water is at its clearest and the pods are fully submerged. For those who prefer being vertical, during low tide, the modules are exposed and retain water, creating mini rock pools that can be explored and enjoyed while wading.