Coastal Bioengineered Reefs as a Sustainable Technique for Coastal Land Building and HabitatRestoration

摘要

Coastal areas in Louisiana and around the globe have been impacted by coastal sediment subsidence and sea level rise. Powerful storms have added to coastal erosion. Louisiana, with 40% of the nation's coastal wetlands, is suffering 90% of the nation'scoastal wetland loss. Coastal bioengineering, using living organisms such as the eastern oyster Crassostrea virginica, to help grow coastal protection, can be cost effective and can protect or even grow coastal land.Two oyster reefs were placed in the Gulf of Mexico off the coast of Louisiana in 2012. Each reef consists of approximately 560 rings; 40 rings across, 7 rows, and 2 layers. The rings are 5 feet in diameter and have a 9 inch wall thickness. Over time, oysters have grown on the rings, increasing the strength and size of the barrier. This phenomenon can help influence future structures to be more sustainable over a longer period of time and increase coastal structures' lifespan.Counts of oysters (size and density) have been made over the last three years, and estimates of land growth have been made over that same period. While the process is dynamic, involving growth, predation, death, and is influenced by tidal and wave events, the overall trend is toward consistent growth of the oysters and growth of land in the lee of the reefs. This paper provides some details of this study and suggests possible ways that this type of coastal bioengineering can aid in enhancing sustainablecoastal protection in Louisiana and other areas.