Living Shorelines As Alternative Methods Of Shoreline Protection

Abstract

Louisiana’s marshes and coastal estuaries are losing habitat at an alarming rate. High rates of sea level rise coupled with coastal subsidence are turning once thriving marsh land into open water. The sediment starved Mississippi River Delta is drowning, making families homes, property, and livelihoods increasingly vulnerable every year. Significant funding is being allocated for projects to offset the increasing erosion including but not limited to diversions, marsh creation, ridge restoration, and shoreline protection projects. Living shorelines, for the sake of this study, can be defined as a form of shoreline protection which helps shoreline stabilization and erosion reduction while still providing estuarine habitat and other ecosystem services. Living shorelines offer an eco-friendly alternative to traditional shoreline protection measures which can be costly, offer little ecosystem services, and often become ineffective by sinking below water level due to highly compactable bottom sediments. This study investigates some of the living shoreline projects completed along the Louisiana coast for porosity and wave attenuation and the subsequent effect on volumetric soil erosion rates. Wave attenuation, while important for reducing wave energy in the shoreward regions, did not show a strong correlation with volumetric erosion rates. However, increasing porosity, ranging from 0% to 35%, was shown to have a relationship with soil volume change rates in that the more porous a structure was, less erosion, and in some cases accretion, was shown across all projects.