Title

Impacts of driving on the beach: Case studies from Assateague Island and Padre Island National Seashores

Document Type

Article

Publication Date

2013

Publication Title

Ocean and Coastal Management

Volume

71

First Page

33

Last Page

45

DOI

10.1016/j.ocecoaman.2012.09.012

Abstract

There is mounting evidence that driving on the beach has a significant biophysical impact, and it has been suggested in a number of recent studies that driving on the beachface leads to a net loss of sediment from the beach-dune system. Identifying a conclusive link between beach driving and beach erosion is, however, complicated by the natural variability of the environment in both space and time, and it has proven difficult to distinguish the driving signal from this background noise. In this respect, the impacts of beach driving are not clear, making it difficult to develop appropriate management strategies to reduce the impact in either degree or extent. LiDAR data from both Padre Island National Seashore and Assateague Island National Seashore are used in the present study to determine if the differences in beach and dune morphology between restricted and open access sections of the beach are associated with beach driving. Results from Padre Island National Seashore suggest that beach driving does not affect the height and volume of the foredunes, but is responsible for a statistically significant decrease in the elevation of the dune crest and base compared to the control section of beach. The decrease in elevation is ascribed to the compaction and pulverization of seaweed wrack that accumulates along the Texas coast in the spring and summer months, and is responsible for the anchoring of sediment for the growth of new vegetation seaward of the foredune. At Assateague Island National Seashore, driving on the beach is shown to cause a statistically significant change in the beach-dune morphology, with smaller dunes set further back from the shoreline within the open access sections of the beach. Despite the changes in dune morphology at both sites, there is no statistically significant difference in beach-dune volume on either side of the beach access road, which suggests that driving on the beach does not lead to a net loss of sediment from the beach-dune system. Driving on the beach does, however, make the foredune at both sites susceptible to scarping and overwash during tropical storms and hurricanes. © 2012 Elsevier Ltd.