Modeling sand wave characteristics on the Belgian Continental Shelf and in the Calais‐Dover Strait

Abstract

A theoretical model able to predict the main geometrical characteristics (crest orientation, wavelength, ...) of sand waves is applied at different locations of the North Sea, where large scale morphological patterns are observed. The predictions of the model are compared with data provided by field surveys and the obtained results show that the model provides a reliable description of the bottom forms generated by tidal currents in shallow seas

Biogeomorphology of coastal seas

“…Moreover, both bedload transport and suspended load transport are included in the model. The model was able to reproduce the sand wave length at different locations on the Belgium Continental Shelf fairly well (Cherlet et al, 2007).…”

“…Hulscher (1996) elaborated on this idea, and found that sand waves are generated by residual vertical circulation cells, whereby sediment at the trough is transported towards the crests. The occurrence of sand waves and sandbanks can be fairly predicted for the North Sea in both a qualitative (Hulscher and van den Brink, 2001) and quantitative way (Cherlet et al, 2007). The latter two studies both used linear stability analysis to determine a specific wave length and an orientation of the most unstable component of the bed perturbations, which can be assumed to coincide with the appearing bedform.…”

“…From these 32 locations, 23 are in the Dutch part of the North Sea (Van Santen et al, 2011), 7 are in the Belgian part of the North Sea (Cherlet et al, 2007), 1 is in San Francisco Bay in the USA (Sterlini et al, 2009) and 1 is in the Gulf of Cadiz in Spain (Németh et al, 2007). The Rouse numbers P at these locations are between 1.9 and 5.0, which is comparable to the range in Rouse numbers P presented in Figure 3.1B.…”

“…For a detailed explanation on the theory behind the use of linear stability analysis for understanding morphodynamic behaviour of coastal systems see Dodd et al (2003). The model used in the present chapter is based on the work by Besio et al (2006) and later modified by Cherlet et al (2007), who modeled sand wave lengths along the Belgium continental shelf. By linking the relations described in Section 4.3 with the idealized model of Cherlet et al (2007), a first insight can be obtained into the possible influence of benthos on the wave length and occurrence of offshore sand waves.…”

“…In summary, the overall effect of different types of biota on the sand wave length is difficult to predict, given the various influences on the different model parameters. Therefore, including the extreme biological factors in the idealized model (Cherlet et al, 2007) is valuable to give some insight into the possible influence biota have on the sand wave length and sand wave occurrence. …”