Erosional blowout dune dynamics, Cape Cod National Seashore

This research explores the morphodynamics of erosional blowout dunes at Cape Cod National Seashore, Massachusetts, USA - an area that hosts one of the highest densities of these features in North America. The project involves examination of historical changes in land use and blowout morphology, exploring linkages to climatic variabilty and storminess/hurricanes, and conducting event-based experiments and computational fluid dynamics (CFD) simulations to characterize airflow and sand transport dynamics within blowouts of different sizes and/or stages of evolution. 

Blowout dunes are formed by wind erosion of pre-existing sandy deposits in coastal and inland settings. Blowout morphodynamics reflect both natural processes of sand deflation and drift as well as human-induced land-use changes (e.g., foot or vehicular traffic), animal activity (e.g., grazing), or climatic events (e.g., drought) that reduce stabilizing vegetation cover and/or enhance aeolian activity. They are often the first features to form in either destabilizing dune terrain (via vegetation death) or rapidly stabilizing landscapes (via localized flow acceleration effects). Little is known on blowout dune initiation, morphodynamics, and relations to climatic variability and/or land use changes, which limits our ability to interpret these features as indicators of climate variability and land use changes.

 

 

 

 

 

 

 

 

A collaborative project with Drs. Patrick Hesp (LSU), Paul Gares and Thad Wasklewicz (ECU) funded by the US National Science Foundation is underway to examine blowout initiation, historical evolution, and event-based morphodynamics at Cape Cod National Seashore and Sandy Neck Beach Park, Massachusetts, USA, which host perhaps the highest densities of blowouts of varying morphology in the world. The research involves close collaboration with the US National Park Service and Town of Barnstable, MA. Specific objectives include to:   

1.     reconstruct historical landscape dynamics using aerial photography to quantify and visualize changes in aeolian activity, dune morphology, land cover, and human activity;

2.     quantify spatial and temporal morphological changes across a range of blowouts using field experiments and aerial and ground-based LiDAR to enhance our understanding of blowout dynamics and evolution; and

3.     analyze historical climate data to identify relations between regional climatic variability and events (e.g., drought, North Atlantic Oscillation (NAO), hurricanes, strong Nor’westers), and dune activity. 

This multi-methods approach is designed to improve our scientific understanding of blowout dune evolution as well as provide new insights on the use of these features as sensitive indicators for climatic and land-use change impacts. 

This research is funded by a US National Science Foundation collaborative Research Grant with Drs. Patrick Hesp (LSU) and Paul Gares (ECU).

Select Publications

Hesp, PA, Walker, IJ (2012). Three-dimensional aeolian dynamics within a bowl blowout during offshore winds: Greenwich Dunes, Prince Edward Island, Canada. Aeolian Research 3(4): 389–399.