A Coastline Perturbation caused by Natural Feeding from a Shoreface-connected Ridge (Headland Sint-André, Belgium)

Verwaest, T.; Houthuys, R.; Roest, B.; Dan, S., and Montreuil, A.-L., 2020. A coastline perturbation caused by natural feeding from a shoreface-connected ridge (headland Sint-Andre, Belgium). In: Malvarez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 701-705. Coconut Creek (Florida), ISSN 0749-0208.This paper explains how a local seaward perturbation, headland Sint-Andre, in the straight sandy coastline of Belgium can persist for centuries. The diffusive longshore transport gradients on the beach are counterbalanced by a sediment supply from off-shore via a shoreface-connected ridge. A UNIBEST-CL+ 1D coastline model is set up to describe the genesis of this coastline feature. From the size and shape of the perturbation and taking into account the diffusivity caused by the longshore transport gradients, the average sand supply from offshore is estimated to be 55,000 m3/year and it is hindcasted that the connection of the ridge to the coastline occurred between 300 and 400 years ago.