Wave Dissipation and Sediment Transport Patterns during Shoreface Nourishment towards Equilibrium

Yuan Li,Mingxiao Xie,Yu Cai,Chi Zhang,Hongshuai Qi,Yigang Wang

doi:10.3390/jmse9050535

Abstract

Implementing shoreface nourishment is an effective method to protect sandy beaches. A better understanding of the equilibrium mechanism of shoreface nourishments is necessary for coastal engineering designs and constructions. Two experiments on the beach profile equilibrium of the shoreface nourishment are carried out under mild wave conditions on the reflective and intermediate beach. It is observed that the shoreface nourishment increases local wave height and strengthens wave nonlinearity by its shallow water depth. The most intense wave breaking dissipation has been found on the crest of the shoreface nourishment, and the distribution of wave energy dissipation rate is more uniform on the quasi-equilibrium profile than that on the initial profile. A process-based numerical model is used to reproduce bed profile evolution successfully. On that basis, it is found that onshore bedload transport is the primary cause for the onshore migration of the shoreface nourishment. The magnitude of bedload transport decreases during the evolution of the shoreface nourishment towards equilibrium. The most intense sediment transport rate occurs over the shoreface nourishment or in front of the shoreline, depending on the ’lee effect’ of the nourishment. Furthermore, the effects of incident wave height, wave period, and sea-level rise on the equilibrium profile of the shoreface nourishment under mild wave conditions are analyzed.

Highlights

Published: 17 May 2021Coastal areas functioning as habitats for amphibians are densely populated and economically developed
The objective of this study is to investigate the wave dissipation and sediment transport patterns during the evolution of shoreface nourishment towards equilibrium under mild wave conditions
Analysis on wave height and wave dissipation in this study are based on short wave components

Summary

Introduction

Published: 17 May 2021Coastal areas functioning as habitats for amphibians are densely populated and economically developed. Coastal communities are currently threatened by climatic change and anthropogenic activities [1,2]. Traditional ‘hard structures’ such as, seawalls and submerged dikes, are constructed mostly focusing on the protections of lives and assets, without taking the environmental health into account [7] These ‘hard structures’ can provide protective services within a certain period, they will cause negative impacts on landscapes, ecosystems, biodiversity, and biological interactions in the long run [2,8,9]. Hs0 (m) Tp (s) Ω Duration (min) A1_2 E1_1 Reflective Intermediate In this experiment, beach bottom elevation was measured by the Trimble scan X configuration scanner with measuring error less than 1 mm.

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Conclusion