Investigating the Impact of Hurricane Harvey and Driving on Beach-Dune Morphology

Beach and dune morphology are spatially and temporally variable, changing over a broad range of scales simultaneously. Strong wind, waves, and storm surge from Hurricane Harvey substantially eroded the beach and dunes along the Texas coast, causing significant scarps and berms. This paper presents information about how anthropogenic activity, such as driving on the beach, affected the response and recover of a barrier island with regard to the post-storm resiliency along the Texas-Gulf of Mexico coast by comparing two adjacent 7 km stretches of coast: a driving section and a limited-access section. A collection of field photos, aerial imagery, and a September 2016 LiDAR-derived digital elevation model (DEM) dataset provide information on pre-storm morphology, while field photos, taken only 3 days after Hurricane Harvey made landfall, and a structure-from-motion (SfM)-derived DEM and imagery provide qualitative and quantitative information about the post-storm morphology. While beach and dune erosion in the non-driving section was restricted entirely to the beach and incipient dune system, the driving section exhibited complex patterns of erosion and deposition along the beach and the entire foredune profile was altered. Despite the hurricane making landfall north of the study site and closer to the non-driving section, beach-dune erosion and scarping was greatest in the southern section which is accessible to public vehicles. Results demonstrate that human activity affects the response and recovery of the beach-dune system along the Gulf side of the island by decreasing alongshore variability in erosion-deposition and limiting vegetative and geomorphic recovery.