The first prototype of a concrete reef structure will be placed in the ocean off Windward Oʻahu later this year or early next.
The $27 million coastal protection project is meant to slow wave energy, reduce impacts to near-shore communities and support a coral reef ecosystem.
The project is funded by the Defense Advanced Research Projects Agency and spearheaded by the University of Hawaiʻi’s Applied Research Laboratory.
"The base structures were purposely designed to both be durable in a high wave energy environment and also reduce wave energy," said lead scientist Ben Jones. "They reduce waves in a gradual way that allows a coral reef, really, to thrive on and behind these structures."
"We're not using typical iron or stainless steel rebar, and we do this because it doesn't corrode. So even over, say, a 50- or 100-year lifespan, the glass fiber rebar will not corrode, which is often one of the modes of failure of reinforced concrete," Jones said.
The coastal protection project has been working with two concrete casting yards, Jensen Precast and GPRM Prestress, to create 60 units.
"They're pretty excited about this. This is different work for them. They're complex shapes. And so they're coming up with some real ingenious ways to create large steel molds to cast these structures," Jones said.
The structures will be placed on the Kailua Bay side of Marine Corps Base Hawaiʻi. Jones said the underwater site is near a rocky area not used by surfers.
He said there have also been discussions about placing concrete reefs in places like Waikīkī.
But the Department of Defense-funded research isn't embraced by all. The Associated Students of the University of Hawaiʻi at Mānoa testified at a regents meeting Thursday against extending the affiliated research contracts with the military.
This interview aired on The Conversation on Sept. 20, 2024. The Conversation airs weekdays at 11 a.m. on HPR-1.
