PERFORMANCE OF PERCHED BEACH NOURISHMENTS

Rosaria Ester Musumeci, Luca Cavallaro, Enrico Foti

Abstract


Perched beach nourishments are popular measures to contrast beach erosion in the presence of steep beaches. Inspired by a real case-study, in the present work the performance of two configurations of the submerged barrier used to protect the toe of the beach are experimentally investigated. Measurements have been gathered concerning wave reflection and transmission, stability and scours around the submerged sill, and beach profile evolution. Both accretive and erosive wave conditions have been considered here. A comparative analysis on the evolution of the two configurations of the sill, shows that the armoring of the filter behind the rubble mound structure is a very effective measure to increase the level of beach protection (e.g. the shoreline retreat under erosive wave attack is reduced to a third). The comparison of the experimental results with an analytical model to predict the equilibrium profile of perched beaches shows that the key phenomena controlling the process are related not only to wave reflection but also to wave dissipation mechanisms at the sill. Moreover, the comparison of the experimental results with field data proves that notwithstanding the several simplifying assumptions considered in the physical modeling, several phenomena are reasonably predicted by the model (e.g. beach evolution, stability and scours).

Keywords


equilibrium profile; submerged breakwater; accretive waves; erosive waves

References


Baquerizo, A., 2005. Reflexión del oleaje en Playas. Métodos de evaluación. PhD Dissertation, Universidad de Cantabria, Santander, Spain.

Chatham, C.E., 1972. Movable-bed model studies of perched beach concept. Proc. 13th Int. Conf. on Coastal Eng., 1197-1215.

Dean, R.G., 1991. Equilibrium beach profiles: characteristics and applications. Journal of Coastal Research, 7(1), 53-84.

Dette, H.H., Larson, M., Murphy, J., Newe, J., Peters, K., Reniers, A., and Steetzel, H., 2002. Application of prototype flume tests for beach nourishment assessment. Coastal Engineering, 47(2), 137-177.http://dx.doi.org/10.1016/S0378-3839(02)00124-2

Foti, E., Cáceres Rabionet, I., Marini, A., Musumeci, R. E., and Sánchez-Arcilla, A., 2011. Experimental investigations of bed evolution in wave flumes: Performance of 2D and 3D optical systems. Coastal Engineering, 58. 606-622.

Goda, Y., and Suzuki, Y., 1976. Estimation of incident and reflected waves in random wave experiments. 15th Coastal Engineering Conference, 828-845.

Gonzalez, M, Medina, R., Losada, M.A., 1999. Equilibrium beach profile model for perched beaches. Coastal Engineering, 36(4), 343-357.http://dx.doi.org/10.1016/S0378-3839(99)00018-6

Losada, I. J., Losada, M. A., and Roldan, A. J., 1992. Propagation of oblique incident waves past rigid vertical thin barrier. Applied Ocean Research, 14, 191-199.http://dx.doi.org/10.1016/0141-1187(92)90014-B

Musumeci, R. E., Pistorio, S., D'Arrigo, A., and Foti, E., 2011. Morphodynamics of a perched beach. Proceedings of the Coastal Sediments 2011, 873-886.

Sorensen, R.M., Beil, N.J., 1988. Perched beach profile response to wave action. Proc. 21th Int. Conf. on Coastal Eng., 1482-1491.

Sumer, B. M., Fredsøe, J., Lamberti, A., Zanuttigh, B., Dixen, M., Gislason, K., and Di Penta,A., 2005. Local scour at roundhead and along the trunk of low crested structures. Coastal Engineering, 52(10-11), 995-1025.http://dx.doi.org/10.1016/j.coastaleng.2005.09.012

Van Rijn, L.C. 1993. Principles of sediment transport in rivers, estuaries and coastal seas, Aqua Publication.

PMCid:1005200

Van Rijn, L.C., Tonnon, P.K., Sanchez-Arcilla, A., Caceres, I., and Grune, J., 2011. Scaling laws for beach and dune erosion processes. Coastal Engineering, 58(7), 623-636.http://dx.doi.org/10.1016/j.coastaleng.2011.01.008


Full Text: PDF

Creative Commons License
This work is licensed under a Creative Commons Attribution 3.0 License.