Laboratory Experiment of a Live Dune Sample to Validate Vegetated Dune Response

Abstract

Abstract Coastal dunes are naturally occurring barriers that serve as defense measures from wave action and storm inundation. To combat coastal erosion, sediment placement efforts consisting of man-made dune construction are commonplace to protect coastal communities and shoreline infrastructure. Few dune construction practices consider the differences between man-made dunes and naturally established dunes regarding engineering and ecosystem services. Vegetation’s role in dune stability has previously been well-documented through field data collection and laboratory experiments, including synthetic or transplanted vegetation. However, limited laboratory comparisons exist between these synthetic vegetation options and naturally formed vegetated dunes. A novel physical modeling experiment was conducted where a naturally established dune transect from the US Southeast Coast was sampled and transported to a wave flume facility for testing under controlled wave conditions. Here, a naturally formed dune with established vegetation is compared to a sand-only dune and a dune constructed with synthetic vegetation. It was confirmed that both the naturally formed dune and the constructed, synthetically vegetated dune were significantly more effective in preventing erosion than a constructed, unplanted, sand-only dune. During testing, the sand-only dune failed 68% sooner than the natural and synthetic dune, furthering the potential of synthetic vegetation as a viable surrogate material for improving dune resiliency during initial dune construction.