Coastal Erosion and a Characterization of the Morphological Dynamics of Arauco Gulf Beaches under Dominant Wave Conditions

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Coastal Erosion and a Characterization of the Morphological Dynamics of Arauco Gulf Beaches under Dominant Wave Conditions
by Mauricio Villagrán 1,*ORCID,Matías Gómez 1ORCID andCarolina Martínez 2,3,4ORCID
1
Department of Civil Engineering, Universidad Católica de la Santísima Concepción, Alonso de Ribera 2850, San Andrés, Concepción 4090541, Chile
2
Instituto de Geografía, Facultad de Historia, Geografía y Ciencia Política, Pontificia Universidad Católica de Chile, Santiago 7820436, Chile
3
Centro de Investigación Para la Gestión Integrada de Desastres Naturales (CIGIDEN), Proyecto 1522A0005 Fondap 2022, Santiago 7820436, Chile
4
ANID—Millennium Science Initiative Program—Instituto Milenio en Socio-Ecología Costera (SECOS), ICN2019_015, Santiago 8331150, Chile
*
Author to whom correspondence should be addressed.
Water 2023, 15(1), 23; https://doi.org/10.3390/w15010023
Received: 4 November 2022 / Revised: 1 December 2022 / Accepted: 13 December 2022 / Published: 21 December 2022
(This article belongs to the Special Issue Erosion and Sediment Transport Processes in Coastal Waters)
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Abstract
Sandy coastlines in Chile currently have strong erosive tendencies. However, little is known about the morphodynamics of these coastlines; such knowledge would allow us to understand coastline changes and incorporate this knowledge into coastal management. Accordingly, the historical scale of coastal erosion and the morphodynamic characteristics of six beaches of the Arauco Gulf, central-southern Chile (36° S), were analyzed to determine the prevailing wave conditions during winter and summer. Historical changes in the relative position of the coastline were determined using DSAS v5.1. The coupled WAVE-FLOW-MOR modules of the Delft3D 4.02 software package were used for the morphodynamic analysis. Using image processing, it was established that erosion predominates in winter seasons for almost every beach analyzed. However, the Escuadrón beach presents this trend both in winter and summer, with rates of up to −0.90 m/year (2010–2021). In addition, accretion was observed in both stations at Tubul beach. On the other hand, numerical models for the dominant conditions predict accretion in the beaches of Escuadrón, Chivilingo, and Arauco, stable conditions for Coronel beach, and erosion in Llico.