Home » Dutch startup Reefy builds 17 “ReefBlocks” in the river Meuse to preserve wildlife and shorelines | Silicon Canals

Dutch startup Reefy builds 17 “ReefBlocks” in the river Meuse to preserve wildlife and shorelines | Silicon Canals

Rijkswaterstaat, the Municipality of Rotterdam, Boskalis, and Reefy announced that they are testing the Reefy artificial reef system to assist nature restoration and conservation efforts in the Meuse tidal region as part of the “Groene Poort” or “Green Gate” initiative.

Boskalis built 17 Reefy units underwater in less than three days, creating a sustainable living breakwater after extensive planning and cooperation with all partners. The artificial coral is roughly 25 metres long and 3 metres high, allowing visitors to see its upper layer during low tide.

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Image credit: Reefy

This pilot project was made possible, besides the four consortium partners, by the technical guidance and assistance of PortXL, Rotterdam Zoo Blijdorp, Burgers Zoo, TU Delft, and Deltares.

How will the reefs help?

Joep van Leeuwen, Senior Consultant Urban Development City of Rotterdam, says that reefs support biodiversity enhancement, storm protection, and tidal environment enhancement of waterfronts.

Jaime Ascencio, co-founder of Reefy, adds, “We need to rethink marine infrastructure and include the right conditions for letting nature thrive. It is important that water and sediments can go through breakwaters, then those appropriate conditions will allow ecological foreshores to develop that can grow with sea level rise.”

“The ReefBlocks provide this and the necessary complexity to boost life underwater. These eco-engineering solutions will be cheaper to maintain compared to traditional structures in the face of climate change.”

According to Leon Haines, co-founder of Reefy, the ecological growth of the coral will be constantly observed for impacts on the overall enhancement of ecosystem services. 

Reefy conducted the baseline biodiversity surveys prior to installation, and in a few months, the project’s groundbreaking biological outcomes are anticipated.

Everything you need to know about the partners


Founded by Jaime Ascencio and Leon Haines, Reefy is an eco-engineering company that combines biology and hydraulic engineering to create nature-inclusive solutions for coastal protection and offshore wind projects.

Reefy’s ReefBlocks are “Lego-like” blocks that were hydrodynamically built and tested in the Deltares wave tunnel. The blocks can be put together underwater to form a stable structure that absorbs wave energy and makes an undersea labyrinth where fish and other species can find shelter and breed.

The bricks have a unique surface pattern and are made of environmentally friendly concrete.

With this, the startup hopes to encourage different types of biological growth, including that of oysters and mussels, to produce a living layer that promotes biodiversity and can expand in response to sea level rise while requiring less upkeep.

Reefy is working on a number of foreign trial and demonstration projects in the Caribbean, Central America, and North America with a variety of goods for both coastal protection and offshore wind in addition to the Rotterdam Reef project.

City of Rotterdam and Rijkswaterstaat:

The City of Rotterdam, Rijkswaterstaat, the Port of Rotterdam, and the World Wildlife Fund have been collaborating since the end of 2013 to create viable, environmentally friendly riverbanks in the river Maas (also known as the river Meuse) in the heavily industrialised and populated region. 

The project is called De Groene Poort, or “Green Gate”.

Breakwaters are required to create a foreshore to keep natural riverbanks preserved and protected from currents and waves of ships. Rijkswaterstaat and the City of Rotterdam are looking for more sustainable solutions for this than the usual rock or stone dams.

The City of Rotterdam and Rijkswaterstaat hope to find a robust and long-lasting solution to reestablish the natural values in the Maas River tidal region by putting these coral inventions to the test in collaboration with Reefy. 

Besides the Groene Poort, the programme River as a Tidal Park is in progress to realise tidal parks in the delta. The City of Rotterdam is one of the partners in this programme.


Boskalis claims to be a global leader in marine, offshore wind and dredging services. It is constantly searching for environmentally friendly options to use in projects around the globe.

The Artificial Reefs Programme from Boskalis helps startups create goods that have a significant beneficial effect. Boskalis provided the project with large machinery and skills for installation in the Nieuwe Waterweg for the test setup. 

With prior postings in Monaco, Kenya, and Panama, this initiative marks Boskalis’ fourth knowledge-building project for artificial reefs under the Artificial Reefs Programme.


Reefy received so-called “golden tickets” from the City of Rotterdam and Boskalis in 2021 to take part in PortXL, a marine accelerator programme. 

Startups and scale-ups are given access to prospective clients through this programme, and they network to try and market innovations. The Rotterdam Reef project, which focuses on the cycle from block manufacturing to reef monitoring, was born by all parties to foster invention.

Diergaarde Blijdorp, TU Delft and Burgers Zoo

Blijdorp Zoo aids businesses by providing a space to serve as a testing ground. Blijdorp collaborates with Delft University of Technology to provide startups with resources and advice for creating new innovations. 

To create their equipment, Reefy collaborated closely with the Burgers Zoo in Arnhem and the Oceanium in Blijdorp. 

A scale replica of the coral placed in the Green Gate can be seen on the visitors’ side of the Science Aquarium in Blijdorp. The model is used to teach tourists about the value of reefs for preserving shorelines and the function of artificial reefs in the restoration of species.


Deltares is a knowledge centre for applied research in the area of water and the subsurface. It focuses on smart solutions, innovations, and apps for people, the environment, and civilisation around the globe.

Reefy has been working with Deltares in technological development and successfully tested ReefBlocksTM in the Deltares wave flume in simulated hurricane conditions.

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