Reef Rehab

Innovative concrete structures mix with corals to defend the coastline during hurricane season

- JEFF YOUNG

ABOUT 200 YARDS OFFSHORE OF NORTH Miami Beach, an underwater experiment is underway. An artificial reef called the Sea Hive will test how a blend of synthetic and natural defenses can help protect some of the nation's most valuable waterfront property against the battering waves of tropical storms.

The Sea Hive is a stacked pyramid of 12-foot-long hexagonal concrete tubes submerged in about 30 feet of water. In cross-section they resemble the pattern of a beehive thus the name and openings along the sides allow water and wave energy to enter.

"Because of their perforated nature they do a really good job of mitigating wave height and wave energy," University of Miami Associate Professor of Marine Biology Diego Lirman told Newsweek.

Lirman is part of a team of engineers, biologists and social scientists developing the coastal defense project that mixes the "gray" of concrete and the "green" of nature-based solutions-in this case, corals.

Corals are Lirman's focus. His lab works to grow and restore corals in South Florida waters and the

Sea Hive is intended to act as both a wave barrier and a base for coral growth. In lab simulations, Lirman said, the concrete structure alone reduced wave energy by 60 to 70 percent, a potentially valuable addition when storms erode the beach and threaten beachfront property.

"But the really cool outcome is that by adding corals, especially using branching corals that cause a lot of friction, you can increase the benefit by anywhere between 10 and 20 percent," he said. "It gives support to this idea that hybrid approaches are much better than just deploying a whole bunch of 'gray' infrastructure, which is what we've done in the past."