THE CONCRETE INDUSTRY needs a few more friends in the aqua-agricultural business like Tyler Ortego, who has created a proprietary mix design for a special concrete element.
Ortego, a biological engineer and owner of ORA Technologies, is the inventor of a method of shoreline control which creates semi-artificial reefs using oysters. His graduate work at Louisiana State University focused on how to use oysters to create erosion barriers.
Ortego's research resulted in two inventions: OysterKrete and OysterBreak. Both employ the oyster's inherent nature of clustering to fill in the gaps of strategically placed submerged precast concrete rings.
OysterKrete promotes oyster attachment to the hardened concrete's surface. Aa roughened surface texture is very important for early growth. OysterKrete is a harsh mixture that results in a hardened concrete that resembles pervious concrete.
OysterBreak focuses on the artificial reef structure. The system uses stacks of specially designed concrete rings similar in size, shape, and weight to spacer rings used on manhole risers, but featuring anchor lugs and wave openings. Each ring is wetcast using the OysterKrete mix design.
These living barriers become structures for shoreline erosion protection. Placed in rows two to three deep, the OysterKrete structure allows tidal water to easily move within the structure, while resisting wave action that causes shoreline erosion.
An advantage of OysterBreak is its design flexibility. Engineers can determine the proper geometry between two segments of OysterBreak reef with coastal engineering analysis. The relationship between OysterBreak segment length (flushing gap interval), flushing gap length, and distance to shore will result in a secure structure that will yield the proper wave–shoreline interaction.
Workers place the rings with enough spacing to accommodate oyster colonization. New oysters can fill the spacing between rings for many generations. On a project on Chesapeake Bay, researchers reported oyster growth after two seasons. Another OysterBreak design advantage is that it is easily expanded. Owners can add additional rings on top of existing structures for future growth.
Ortego has licensed his two inventions to Wayfarer Environmental Technologies (WET), of Hunt Valley, Md. In turn, WET is using Oldcastle Precast as its exclusive manufacturer.
The structures offer engineers another tool to help solve shoreline erosion problems, says Dale Robicheaux, who markets these products for Oldcastle. Oldcastle engineers can aid engineers in designing customized elements to create living structures to mitigate shoreline erosion.
More than an Erosion Barrier Wall
There is an environmental benefit from creating living oyster reefs. Where oyster beds are under duress, OysterBreak provides a safe haven. The structures give oyster larvae a secure place to nest. The new permanent residents provide millions of larvae each breeding season.
OysterBreak structures help regenerate the oyster beds. When an oyster dies, the uncemented valve falls to the seabed. In short time, the newly shelled covered area becomes a viable harvest bed. These oyster reefs have additional environmental benefits. Reestablished reefs enhance habitats for commercial fishing and expand sport fishing.