In the midst of a climate crisis, temperatures and sea levels are rising at unprecedented rates. This is creating stronger and more frequent disasters. This has created stronger hurricanes with higher wind speeds and higher precipitation rates. In coastal areas, erosion is a growing concern to the environment and the tourism industry alike. This underscores the current urgency for finding engineered solutions to protect coastlines.

Coastal erosion is a global problem. The United States alone spends $150 million on beach nourishment every year to attempt to combat the $500 million per year property and land losses caused by erosion. Around the world, nearly a quarter of all beaches are eroding. This threatens biodiversity and leaves coastal marine life potentially irreparable after highly damaging storms.

Beyond the loss of sands and soils, coral reefs have declined by 50% in the last 30 years. Oyster reefs have dropped an even more staggering 85%. Seagrass beds have dropped 29%. This is a challenging loss as they can capture 35 times more carbon than the Amazon rainforest.

Engineering solutions: Breakwaters and artificial reefs

Breakwaters often take the form of short mounds of rubble that can provide wildlife with some forms ofThe Dry Tortugas National Park. This submerged ship’s wheel has become an artificial reef. Photo: Brett Seymour, Submerged Resources Center, NPS, public domain. shelter. Artificial reefs can be natural breakwaters, but are often not sustainable or stable. Large sunken ships, old tires and vehicles are often utilized as structures for coral to live off and fish to live in. Coral reefs can dissipate 97% of wave energy from waves, storms and even tsunamis before even reaching shorelines.

The modern engineering solution: Reef enhancing breakwater

To create a holistic solution approach to the erosion and marine life loss problem, Jaime Ascencio and Leon Haines created “Reefy.” After five years of research from Ascencio and Haines’ experience in marine biology and five years of coral reef restoration, this living breakwater solution was invented.

BlueInvest, the EU’s innovation and investment platform for ocean technology, invested a whopping￡500,000 toward this new technology. Reefy also won the BlueInvest Awards in 2021. Reefy plans to attain an additional ￡1 M for furthering biodiversity and marine construction innovations.

In 2023, Rotterdam’s first living breakwater was placed in the form of a 102 ton Reefy modular reef in the Maas river. All 82 ft of length and 10 ft of height of this breakwater work to support five times more species effectively tripling biodiversity and save up to 60% of material volumes as opposed to traditional options.

This project represents the pilot of ReefBlocks. It is a part of the “Green Gate” project that works to renew the intertidal landscapes. There is heavy port activity in Rotterdam, making it a prime location to conduct the two-year testing in real application.

Growing with nature

Reefy is a modular, artificial reef designed to “rewild the ocean” by restoring biodiversity and creating a sustainable wave barrier. The unique, adaptable concept is formed out of individual bricks that resemble Legos. There are protrusions to interlock with other blocks to form any shape needed. There are three holes These blocks become home to sea life. Image source: Reefythat were hydrodynamically designed for water flow. These blocks are made of a low carbon concrete. They are also permeable to promote water quality.

These patented blocks can serve as places for oysters and mussels to grow and flourish. Sturgeons and eels can also take shelter among the complex structures. The rough, rippled texture of the blocks creates an engaging and beneficial surface for corals and bivalves to grow. Filter feeders can live in these blocks, further improving water quality. Eco-blocks can be placed strategically within the traditional Lego-blocks to form target habitats for local species. Seagrass beds can also thrive behind the breakwater, providing more support for marine life.

This living breakwater can protect coastlines from hurricanes and flooding. The oysters and coral form a living layer that can self-repair post-storm and rise with the changing sea levels. This is a level of resilience that is critical to accommodate the ever-changing climate crises.

Tried-and-tested approach to environmental betterment

The Reefy design was tested first in the Eastern Sheldt Flume at Deltares Research Institute. It was forced under hurricane-level wave scenarios. It was able to dissipate 90% of the wave energy successfully. The flow was also assessed to determine ecological growth potential.

A digital twin of the ocean was then created via computer model to input wave size and current velocity for design. It is also actively tested and monitored to see if biodiversity is flourishing. A reef paint that is made with increased calcium levels and engineered to help oysters grow and a paint for coralline algae are active experiments.

Through rigorous testing it was determined that coral could grow on biodegradable biopolymers. Wageningen University assisted with toxicity and trace element testing. Positive results are being seen from coral growth observed on various low carbon and sustainable material alternatives.

Reefy is continuously being tested over its two year trial-period in Rotterdam. It is evaluated for its two major claims: ecological benefit and engineering success. This will help elucidate whether more implementations are feasible and what aspects can be optimized. eDNA and film samples were taken in the beginning of the trial period. They will be compared to the final result after two years.

It is crucial to efficiently and continuously monitor this new technology. It is important to ensure that unforeseen, adverse effects are not present in the environment. It is as necessary to track expected success and failures as it is unsuccessful ones. This is all in the name of locating and facilitating the best options to protect coastal shores and rebuild biodiversity for thriving ecosystems.

The future of reefs

Reefy plans to expand future projects into Mexico and the Southeastern United States. There is ongoing testing in the North Sea to introduce oyster habitats. Gili Air, an island in Indonesia, has been historically bombarded with storm surge and sea level rises. This has created losses of protective coral reef and seagrass fields. Reefy has implemented a pilot project to dually serve as coastal protection from waves and a place for new corals to grow and create a habitat for population resurgence. There are many restoration applications that this reef enhancing breakwater design can accommodate: coral reef, oyster reef and seagrass.

[Researchers build 3D printed coral homes for fish....on GlobalSpec]

Reefy has been awarded first place winner in many challenges and innovation projects. It was dubbed the perfect biodegradable reef for the 2020 Offshore Wind Innovation Challenge and winner of the NENovation Award in 2020. They received assistance from BlueInvest, the CleanTech Challenge, PortXL maritime accelerator program, and Deltares. They are supported by the Boskalis Artificial Reef Program, Rijke Noordzee and the Nature Conservancy as well.

There is no doubt that the future of coastal protection and coral reef restoration will rely heavily on breakwaters such as Reefy. By combining ecology and engineering, it is becoming possible for engineering solutions to interact with and support nature. Instead of fighting climate change, finding mitigation strategies that allow for rewilding the natural ecosystems is a sustainable solution that will not further damage precious marine life and natural aquatic patterns.