Fuzzy Boundaries: Classifying the Beach-dune Interface

Identifying the precise location of a coastal foredune toe is an important factor for determining the processes responsible for dune development and how to manage a recovering dune system. The dune toe is commonly identified using the inflection point, least-cost-path algorithms, or relative relief. These methodologies are relatively simple to implement using modern GIS techniques; however, they do not offer a cohesive definition of what defines a dune toe. This lack of consistency defining beach-dune boundaries can lead to problems for coastal managers with sea-level-rise and future climate uncertainty. Multiple factors such as beach width, wind direction and speed, wave height, vegetation abundance, and beach moisture level are unused when determining the location of transition between beach and foredune. The purpose of this study is to delineate the position between the beach and foredune where dune building processes begin to establish a more objective definition for the dune toe. Sample data from Brackley Beach, Prince Edward Island is provided. Preliminary results indicate the feasibility of utilizing remotely sensed data to characterize the interactions between multiple spatiotemporal dune building processes. It is argued that from this understanding a practical model can be developed to determine a process-based dune toe position. Furthermore, this research has the potential to determine the conditions that are universally applicable to coastal systems in both various stages of recovery and geographic location.