This research examines the relations between near-surface airflow dynamics and sediment transport over complex, vegetated beach-foredune terrain. The project involves several event-based experiments at a variety of study sites to investigate the morphodynamics of coastal dunes so as to better understand and model their role in coastal sediment budgets and their natural erosion-rebuilding regime.
The onshore movement of littoral sediment via wind (aeolian) action to beaches and dunes is a key component of some coastal sediment budgets. Foredunes maintained by this process provide distinct, limited natural habitat in the coastal zone and important stores of sand that act as a buffer against wave attack and sea-level rise. This research explores the complex interactions between airflow, beach-dune terrain, vegetation, moisture and fetch effects, and sediment transport in an effort to improve our understanding of how airflow dynamics control the mass balance in various backshore settings (vegetated & unvegetated foredunes, wave cut scarps, eroding dune blowouts).
Much of this research has been conducted in the Greenwich Dunes, PEI National Park in eastern Canada via collaboration with Drs. Robin Davidson-Arnott (Guelph), Patrick Hesp (LSU), Bernie Bauer (UBC-Okanagan), Jeff Ollerhead (Mt. Allison) and Irene Delgado-Fernandez (Edge Hill, UK). Event-based experiments complement a longer-term monitoring program of foredune morphology in response to seasonal variations in wind climate, sand transport potential and storms. From this research, models that describe the seasonal to interannual morphodynamics of beach-foredune systems are being developed.
This research is sponsored by Dr. Walker's ongoing NSERC Discovery Grant.
Chapman, CA, Walker, IJ, Hesp, PA, Bauer, BO, Davidson-Arnott, RGD (2012). Turbulent Reynolds stress and quadrant event activity in wind flow over a coastal foredune. Geomorphology 151-152:1-12.
Walker, I.J., Hesp, PA, Davidson-Arnott, RGD, Bauer, BO, Namikas, SL, Ollerhead, J (2009). Responses of three-dimensional flow to variations in the angle angle of incident wind and profile form of dunes: Greenwich Dunes, Prince Edward Island, Canada. Geomorphology, 105(1-2):127-138.
Walker, IJ, Davidson-Arnott, RGD, Hesp, PA, Bauer, BO, Ollerhead, J (2009). Mean flow and turbulence responses in airflow over foredunes: new insights from recent research. J. Coastal Research, SI56: 366-370.
Hesp, PA, Walker, IJ, Namikas, SL, Davidson-Arnott, RGD, Bauer, BO, Ollerhead, J (2009). Storm wind flow over a foredune, Prince Edward Island, Canada. J. Coastal Research, SI56: 312-316.