Study of Shoreline Changes Due to Tidal Flood at the Coastal City of Meulaboh

Abstract

The coastline is constantly changing over time. The process of change that occurs continuously makes the coastline dynamic. Shorelines are vulnerable to changes caused by natural and human factors. One of the causes of shoreline changes due to natural factors is tidal flooding. Tidal floods cause abrasion of the coastline and create inundation on land. The coast of Meulaboh City has experienced tidal floods in 2020. The tidal floods that occur make the coastline abrasion and residential areas inundated. This study aims to determine the shoreline changes and the shoreline recovery process due to abrasion and accretion after tidal floods from 2020 to 2021. The shoreline in July 2019, 2020 and 2021 were analysed using DSAS tools to see horizontal shoreline changes. Measurement of the transverse profile of the beach was carried out 17 times in 12 transverse profiles. This measurement aims to map the profile condition after the tidal flood in July 2020. Measurement data for each profile was analysed using the EOF method to see vertical shoreline changes one year after the July 2020 tidal flood. Based on DSAS analysis, the shoreline conditions after tidal flooding (2019-2020) regressed with an average regression of 25.48 m and showed an accretion process after a year (2020-2021) with an average accretion of 14.38 m. Shoreline recovery due to tidal flooding can be seen well based on measurements for 1 (one) year and the results of Empirical Orthogonal Function (EOF) analysis. The recovery pattern is visible after 4 months of tidal flooding in July 2020. The beach profile tends to experience an accretion process in the 8th to 13th measurements and tends to experience abrasion in the 16th to 17th measurements. This shows that the accretion process on the transverse coastal profile is influenced by the east wind season, and the abrasion process generally occurs in the west wind season.