3D Physical Modeling of an Artificial Beach Nourishment: Laboratory Procedures and Nourishment Performance

André Guimarães,Paulo A Silva,Carlos Coelho,Fernando Veloso-Gomes

doi:10.3390/jmse9060613

André Guimarães, Paulo A Silva + Show 2 more

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https://doi.org/10.3390/jmse9060613

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Abstract

Beach nourishment represents a type of coastal defense intervention, keeping the beach as a natural coastal defense system. Altering the cross-shore profile geometry, due to the introduction of new sediments, induces a non-equilibrium situation regarding the local wave dynamics. This work aims to increase our knowledge concerning 3D movable bed physical modeling and beach nourishment impacts on the hydrodynamics, sediment transport, and morphodynamics. A set of experiments with an artificial beach nourishment movable bed model was prepared. Hydrodynamic, sediment transport, and morphological variations and impacts due to the presence of the nourishment were monitored with specific equipment. Special attention was given to the number and positioning of the monitoring equipment and the inherent constraints of 3D movable beds laboratory tests. The nourishment induced changes in the beach dynamics, leading to an increase in the flow velocities range and suspended sediment concentration, and effectively increasing the emerged beach width. Predicting and anticipating the morphological evolution of the modeled beach has a major impact on data accuracy, since it might influence the monitoring equipment’s correct position. Laboratory results and constraints were characterized to help better define future laboratory procedures and strategies for increasing movable bed models’ accuracy and performance.

Highlights

According to [1], from the 1980s onward, due to the failure of many “hard coastal engineering structures”, the “soft engineering” coastal protection interventions became more appealing from the technical and economic point of view
This work aims to increase knowledge related to 3D movable bed physical modeling, with special focus on the required setup and configuration of the experiments and monitoring procedures, in order to obtain tangible data that allow the proper assessment of the nourishment morphological, hydrodynamic, and sediment transport impact
The results show that the beach tends to an equilibrium that is independent of the nourishment performed and allows the estimation of the time scale of the nourishment existence

Summary

Introduction

According to [1], from the 1980s onward, due to the failure of many “hard coastal engineering structures” (e.g., groins, breakwaters, or revetments), the “soft engineering” coastal protection interventions (e.g., artificial beach nourishments) became more appealing from the technical and economic point of view. Physical modeling of coastal interventions, such as beach nourishment, helps in understanding the nourishment impacts on the beach morphodynamics and physical processes, assessing its performance [3]. There are several works that address 2D physical modeling in general [4,5], and more precisely, artificial nourishments [6,7]. These are usually specific to a certain sediment transport mechanism or morphological element of the beach (e.g., dune stability). It was intended to obtain hydrodynamic, sediment transport, and morphodynamic data concerning the performance of artificial nourishments (Scenario A)

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