This paper presents an innovative model named sbm,rnwhich aims to quantify sub-tidal beach bathymetry from timeaveragedrnvideo observations of wave breaking. Sbm relies on the updatingrnof an initial beach bathymetry, either surveyed or obtainedrnfrom a previous video image, through assimilation of video-derivedrnand model-predicted patterns of wave dissipation. Model applicationrnalong 2 cross-shore arrays at a multiple-barred beach at Egmond hasrndemonstrated the model’s capability to reproduce the shoreward migrationrnof the outer bar and associated net accretion of sand in thernnearshore part of the surf zone, during the ?rst year after putting inrna shoreface nourishment. With a vertical o?set of 20 to 40 cm aroundrnthe bar crest, pro?le deviations are marginal at the seaward face ofrnthe bars, while maximum deviations up to 80 cm are found in therntrough region, owing to lack of wave dissipation information. Beingrncost-e?cient, this new method o?ers the potential to contribute importantlyrnto the monitoring of state indicators on coastal safety, beachrnrecreation and other functions of coastal systems, with high resolutionrnin time and space.
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