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

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.

Sediment Dynamics in Artificial Nourishments

“…Ferreira et al [9] studied the effects of artificial nourishment on the longshore sediment transport and consequently on the morphological evolution at the intervention site and nearby areas over a time span of 5 years. In a different approach, Guimarães et al [11] used 3D movable bed physical modelling to test the impacts of beach nourishment on hydrodynamics, sediment transport, and morphodynamics. Nourishments may also have ecological consequences.…”