Experimental simulation of sandy beaches under waves and tides: hydro-morphodynamic analysis

Khoury, A., Jarno-Druaux, A., and Marin, F., 2013. Experimental simulation of sandy beaches under waves and tides: hydro-morphodynamic analysis Proceedings 12^th International Coastal Symposium (Plymouth, England), Journal of Coastal Research, Special Issue No. 65, pp. 1791–1796, ISSN 0749-0208.-->

Numerous studies have been carried out on sandy beach morphology; however, the physical processes which govern beach morphodynamic are still not well understood, despite the significance of this subject in view of the direct applications for coastal erosion. The present work brings a contribution to the study of these processes from well controlled tests carried out in a 10-m-long and 0.49-m-wide wave flume with macro – and mega-tidal regime simulations. The tests were carried out with very fine or fine sand of relative density s=2.65. The incident waves and the free surface in the shoaling zone were measured with resistive probes. The wave breaking height and the free surface in the swash zone were recorded with an optical method. The temporal evolution of bottom profiles was obtained using an acoustic method. Intertidal bars were generated; such bars were previously not observed in physical modeling to the authors' knowledge. Present experimental results are compared with field observations. Formation processes of intertidal bars are analyzed; we show in particular the significant effect of the relative tide range, of waves asymmetry, and of subtidal bars on these processes. Small local variations of the beach profile in the surf zone exhibit significant outcomes on the runup.