Applicability of video-derived bathymetry estimates to nearshore current model predictions

Radermacher, M., Wengrove, M.E., Van Thiel de Vries, J.S.M., Holman, R.A., 2014. Applicability of video-derived bathymetry estimates to nearshore current model predictions. In: Green, A.N. and Cooper, J.A.G. (eds.), Proceedings 13th International Coastal Symposium (Durban, South Africa), Journal of Coastal Research, Special Issue No. 70, pp. 290–295, ISSN 0749-0208.In the framework of swimmer safety, coastal managers desire accurate nearshore current predictions obtained from numerical models. To this end, detailed and up-to-date bathymetry is a necessity. Remote sensing techniques for bathymetry estimation are a promising solution. The focus of this paper is to assess the performance of wavenumber-based bathymetric inversion using Argus imagery (also known as the cBathy algorithm) as a feasible input bathymetry for numerical models to make reasonable nearshore current predictions. Numerical flow simulations on a cBathy bed are compared to simulations on an in-situ surveyed bathymetry. Results demonstrate that simulated nearshore currents on a cBathy bathymetry have a root-mean-square error in the order of 10 cm/s (magnitude) and 40 degrees (direction) when compared to simulated currents on a surveyed bathymetry. In the intertidal zone cBathy should be combined with a different method for bathymetry estimation in order to decrease these errors.