Sediment resuspension and nepheloid layers induced by long internal solitary waves shoaling orthogonally on uniform slopes

• Published in: Continental shelf research 2014-01, Vol.72, p.21-33
• Main Authors: Bourgault, D., Morsilli, M., Richards, C., Neumeier, U., Kelley, D.E.
• Format: Article
• Language: English
• Subjects: Computer simulation; Continental shelves; Erosion; Internal solitary wave; Mathematical models; Nepheloid layer; Numerical modelling; Sediment; Sedimentary structures; Sediments; Slopes; Solitary waves; Transport
• ISSN: 0278-4343; 1873-6955
• DOI: 10.1016/j.csr.2013.10.019

Two-dimensional, nonlinear and nonhydrostatic field-scale numerical simulations are used to examine the resuspension, dispersal and transport of mud-like sediment caused by the shoaling and breaking of long internal solitary waves on uniform slopes. The patterns of erosion and transport are both examined, in a series of test cases with varying conditions. Shoreward sediment movement is mainly within boluses, while seaward movement is within intermediate nepheloid layers. Several relationships between properties of the suspended sediment and control parameters are determined such as the horizontal extent of the nehpeloid layers, the total mass of resuspended sediment and the point of maximum bed erosion. The numerical results provide a plausible explanation for acoustic backscatter patterns observed during and after the shoaling of internal solitary wavetrains in a natural coastal environment. The results may be useful in the interpretation of some sedimentary structures, and suggest an effective mechanism for offshore dispersal of muddy sediments. •We examine sediment resuspension induced by shoaling internal solitary waves.•These waves can resuspend muddy-like sediment and cause nepheloid layers.•The length of the internal swash zone (Ls) is an important parameter.•The length of nepheloid layers depends on impacting wave energy and Ls.•Results may provide guidance for interpreting sedimentary structures.