Delft start-up Reefy builds reef in the Maas for nature and water safety.

Rotterdam 24 June 2022 – In cooperation with the municipality of Rotterdam, Rijkswaterstaat and Boskalis, the Delft-based innovative start-up Reefy is going to test a modular artificial reef system that both protects the shore from large ship waves and stimulates nature.


Reefy is a young company from Delft that combines biology and hydraulic engineering to develop nature-inclusive solutions for water safety.

The Reefy innovation consists of gigantic “lego-like” blocks, which have been hydrodynamically designed and tested in the Deltares trench. By putting these blocks together underwater, a stable structure is formed that breaks waves but also creates an underwater labyrinth where fish and other species can shelter and breed. The blocks are made of durable concrete with a special surface texture. With this, the start-up wants to stimulate all kinds of biological growth, such as oysters and mussels, to create a living layer that stimulates biodiversity and can grow along with sea level rise, thus reducing the need for maintenance.

The history of Reefy

The Delft-based start-up Reefy was founded by Jaime Ascencio and Leon Haines. Ascencio worked as an engineer in Mexico and the Caribbean Sea, where he sought sustainable solutions for resorts against coastal erosion. The current artificial reefs on the market turned out to be unstable and could not be used as breakwaters. To find a solution, he went to TU Delft to study for a Master’s degree in Coastal Engineering. Haines is a marine biologist who, after studying Integrated Coastal Management / Marine Biology, spent five years working on coral reef restoration projects on islands in Thailand, the Maldives and Indonesia.

Reefy Co-Founders Jaime Ascencio (left) & Leon Haines (right) proudly displaying the signatures

The Green Gate: Municipality of Rotterdam and Rijkswaterstaat

Since the end of 2013, Rotterdam municipality, Rijkswaterstaat, the Port of Rotterdam Authority and the World Wildlife Fund have been working together to create sustainable, natural river banks in the Nieuwe Waterweg and Scheur. One of the ways they are doing this is with clean residual materials from the construction industry. The project is called ‘The Green Gate’. To keep these natural banks in place and protect them from the waves of ships and the currents, breakwaters are needed as foreshores. Rijkswaterstaat and the Municipality of Rotterdam are looking for more sustainable solutions than the usual quarry stone. By testing these reef innovations in collaboration with Reefy, the Municipality of Rotterdam and the Department of Public Works hope to find a resilient and sustainable solution to restore the natural values in the tidal area of the Maas.


As an international leader in dredging, offshore wind and maritime services, Boskalis is always looking for sustainable alternatives to implement in projects around the world. The Artificial Reefs Program of Boskalis supports innovative start-ups in the development of products to realize large-scale positive impact. Boskalis will help install the project in the Nieuwe Waterweg with large-scale equipment and knowledge. This project is also the fourth knowledge development project of Boskalis in the field of artificial reefs under the Artificial Reefs Program, with previous placements also in Monaco, Kenya and Panama.


In 2021, the Municipality of Rotterdam and Boskalis gave Reefy so-called ‘golden tickets’ to participate in the PortXL maritime accelerator programme. In this programme, start-ups and scale-ups are connected with potential clients and networks to test and bring innovations to the market. The Rotterdam Reef project, focusing on the chain from block production to reef monitoring, has emerged from this with pleasant collaborations from all parties to stimulate innovation.

Blijdorp Zoo

Zoo Blijdorp helps innovative companies by creating space as a testing ground. In cooperation with TU-Delft, Blijdorp offers facilities and guidance for startups to develop new technologies. Reefy has worked closely with the Oceanium in Blijdorp to develop their technology. Behind the scenes, the startup grows coral on various sustainable concrete alternatives to develop the perfect material for reef restoration. In front of the screens, in the Science Aquarium, Reefy has installed a scale model of the reef that will also be installed in the Green Gate to teach visitors about the use of artificial reefs for nature restoration.


The four parties signed a cooperation agreement on 24 June. The planning is to install the reef, the Rotterdam Reef, in October 2022. After that, the technical stability and ecological development will be monitored.