Author(s): Carolina Martinez; Ana Mendonca; Rute Lemos; Conceicao J. E. Fortes; Diogo Mendes

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Keywords: Physical modelling; Hybrid solutions; Stepped revetments; Overtopping

Abstract: Coastal revetments are commonly built along the sea-land interface to control coastal retreat. These coastal defence structures can also protect existing infrastructures from coastal hazards, such as wave overtopping and flooding. An interesting option to upgrade already existent rock revetments would be the use of steps because such a solution may improve coastal amenities by offering seating and viewing areas. Nevertheless, currently available empirical wave overtopping formulations do not account with a hybrid solution composed by rock and stepped coastal revetments. Therefore, physical modelling tests have been carried out with two revetment cross-sections: (i) a conventional double layer rock armour slope and (ii) a hybrid one where the upper layer of rock was replaced with concrete steps. Existing semi-empirical formulations provided in the EurOtop Manual were compared with measured values of the relative mean wave overtopping discharge. Results showed that semi-empirical formulations underpredict the relative mean wave overtopping discharge values by up to a factor of 55 for rock-only revetments and up to 65 for hybrid rock and stepped revetments. Moreover, the relative mean wave overtopping discharge values of hybrid revetments were not completely well described by the variable that incorporates the relative freeboard and the breaker parameter.

DOI: https://doi.org/10.64697/978-90-835589-7-4_41WC-P1937-cd

Year: 2025