The Effect of Vegetation Density on the Resilience of Coastal Dune Systems Against Wave-Induced Erosion

Coastal Dune systems often are the first line of defense against storm surge and wave attack for coastal infrastructure and communities. The preservation of existing dune systems and the restoration of degraded ones should be given high priority by coastal managers and stakeholders. Dunes with healthy vegetation growth are believed to provide an even higher resilience against wave-induced erosion. However, very little research currently exists on quantifying the effect that plants have on dune stability. In particular, the correlation between the density of the vegetation growing on the dune and the added resilience against wave attack has not been investigated. Authorities such as the Texas General Land Office (Texas GLO) or the Natural Resources Conservation Service (NRCS), operated by the United States Department of Agriculture (USDA), have established general guidelines for dune restoration (Patterson, 2005; Williams, 2007) These guidelines however are not based on any scientific analysis. This research is a first step towards closing this knowledge gap by means of a physical model experiment. The general idea is to find the optimal plant density (i.e. plants per area) for a specific type of plant to protect against wave-induced dune erosion. The findings may guide further experiments with different plant types and may be adapted as guidance for real-life dune restoration projects