To Fight Coastal Erosion, Design a Bespoke Artificial Reef

It started in the Caribbean Sea. Jaime Ascencio, then a business development engineer working across Latin America, was eager to find sustainable ways to combat the coastal erosion that was eating away at the region’s treasured beaches—and threatening the tourism dollars brought in by its seaside resorts. “If there is no sand, there are no guests,” he says. But Ascensio, who knew that artificial reefs could make for natural breakwaters, could only find solutions that were neither sustainable nor stable enough to resist the force of the waves. So he went on to get a master’s in coastal engineering at the celebrated Delft University of Technology in the Netherlands—and developed one himself.

After more than five years of research and development, the fruits of his labor were just submerged in the Maas river, just outside of Rotterdam, the Netherlands: 17 blocks, six tons each and made of low-carbon concrete, are now stacked on the river floor. The resulting structure—82 feet long and almost 10 feet high—makes up Rotterdam’s first living breakwater, an artificial reef that will restore marine biodiversity and double as a more sustainable wave barrier against the turbulence caused by the tens of thousands of ships that sail in and out of Europe’s largest port every year.

Officially called a Reef Enhancing Breakwater, the underwater structure is the first project of Reefy, a startup Ascensio cofounded with Leon Haines, a marine biologist who has spent five years working on coral reef restoration projects in Thailand, the Maldives, and Indonesia. Next up on Reefy’s list are similar projects in Mexico and the Southeast coast of the United States (which is already a veritable playground for artificial reefs).

In many ways, the underlying principle behind the startup—that rewilding the ocean can protect the coastline—already exists in nature. All over the world, coral reefs act as a natural buffer, protecting coastal regions from waves, storms, and tsunamis. According to a group of researchers who analyzed corals in all corners of the world, coral reefs can dissipate a staggering 97 percent of wave energy before it reaches the shoreline. Corals also support more species per unit area than any other marine environment while covering only 0.01 percent of the ocean floor.

Except coral reefs are dying from the relentless stress caused by climate change. This much-documented demise has given rise to myriad artificial reef solutions over the years—some unintended, others highly engineered. These run the gamut from sunken ships to purposefully submerged old US army tanks, NYC subway cars, eerie underwater sculpture parks, and dome-shaped coral skeletons preseeded with coral fragments by robotic arms.