Science is at the core of Reefy. Before testing anything in the water we conduct thorough experiments and monitoring of key components and the environment to ensure reliability, sustainability and constructability.

The Rotterdam Reef

In March 2023 Reefy successfully installed the Rotterdam Reef in collaboration with The Ministry of Infrastructure, Boskalis and the City of Rotterdam. This large scale pilot project is part of the "Green Gate" program, where the government aims to restore the intertidal environment for nature in the Meuse/Rhine delta. Breakwaters are required to protect these soft shores against large ship wave from Port activity. In order to meet EU Water Frame Work Directive targets the government was in search of innovative solutions. Reefy was chosen to pilot it's technology in light of an upcoming project of 4km of foreshore development.

The next 2 years Reefy will closely monitor both ecology and engineering parameters for system optimization and future large scale implementation.

Dry-testing experiments

To develop an efficient underwater installation technique for the giant Reefblocks, Reefy conducted dry testing experiments in collaboration with Boskalis. During these tests an installation tool was developed that can place the blocks accurately with minimal tolerances on the sea floor with the help of advanced GPS technology. Results from these experiments lead to further optimization of the living breakwater units, ready for deployment.

Wave flume experiments

Reefy performed extensive wave flume testing in the world-famous 110m long Eastern Sheldt Flume at Deltares. Complex ecological configurations of the ReefBlocks were tested and proven to be stable in hurricane force wave conditions. The structure showed to be a highly effective wave attenuator by dissipating up to 90% of the wave energy. Ecological data such as flow within the structure were also measured. This data allows us to design for a combination of hydrodynamic and ecological purposes.

Material and coral experiments

Reefy has tested a variety of sustainable materials for reef restoration in collaboration with Blijdorp Zoo in Rotterdam and Burgers Zoo in Arnhem. We also performed toxicity and trace element testing with Wageningen University. In Burgers Zoo, Reefy successfully grew coral on fully biodegradable biopolymers. This can allow coral to grow whilst the substrate slowly disappears, leaving only nature. In Blijdorp Zoo, Reefy is currently testing the growth of corals on sustainable and low emission concrete alternatives with great results!

Living lab: Indonesia

On the island of Gili Air, in Indonesia Reefy works together with Gili Shark Conservation, the Coral Catch program, TUDelft and Conservation Diver to test sustainable and resilient approaches to reef restoration. Our focus in this living lab is on optimizing materials for coral recruitment and selection of heat resilient coral whilst maintaining the maximum genetic diversity.


Monitoring is a key part of the activities of Reefy. Before and after installation we need to understand the ecosystem and hydrodynamics in an area to design the best solution for both coastal protection and ecology. Monitoring is crucial for learning and optimizing the Reef enhancing breakwater. At the site of the Rotterdam Reef project the founders got wet to take eDNA samples and film video transects. This status quo will be compared during a two year monitoring campaign in collaboration with the Municipality of Rotterdam.

Team scientific publications

Jaime Ascencio:
Stopping waves with marine vegetation:

Leon Haines:
A new heat resilient coral for resilient reefs

Daan Houtzager:
Stability in breakwaters

Rewilding the ocean to protect the land.

© 2022

Delft, The Netherlands

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