Coastline Change Analysis using Landsat-8 on Rebana Metropolitan Area, West Java

Abstract

The Rebana metropolitan area is an industrial area development covering Cirebon-Patimban-Kertajati to support accelerated economic growth, especially in the West Java region. In order to minimize failures in supporting the development targets of the Rebana metropolitan area, it is necessary to carry out spatial planning with consideration of the hazard aspects in the development area. One of the aspects that need to be studied further is the dynamics of the coastal area such as coastline changes that occur due to erosion or sedimentation. Analysis of erosion and sedimentation is essential for further studies to be carried out regarding the factors that cause erosion and sedimentation and how to protect and prevent them in the future. This research utilizes remote sensing techniques and integrated geographic information systems (GIS) to identify coastline changes from 2017-2022 in the coastal areas of Subang, Indramayu, and Cirebon districts which are included in the Rebana metropolitan area. In this study, Landsat-8 satellite imagery is used to identify and quantify Spatio-temporal changes that occur in the coastal area of the Rebana metropolitan area in 6 years. The Normalized Difference Wetness Index (NDWI) algorithm is used to separate wet and dry objects which are interpreted as bodies of water and land. Thresholding the results of the NDWI algorithm along with the on-screen digitization approach was carried out for coastline extraction. The calculation of coastline changes is carried out using the Digital Shoreline Analysis System (DSAS) so that the rate of change of coastline in the study area is obtained. During the study period, the results showed that the average erosion rate in the Rebana metropolitan area was -3.66 m/year and the average sedimentation rate was +6.28 m/year, where the greatest erosion rate occurred in Kapetakan sub-district, Cirebon Regency with an average rate -7.63 m/year, and the greatest sedimentation rate occurs in Pusakanagara sub-district, Subang Regency with an average rate +24.64 m/year. Karangampel Sub-district in Indramayu Regency has 79.89%, the widest erosion area of its total coastline length, and Balongan Subdistrict, Indramayu Regency has the widest sedimentation, 91.37% of the total coastline length. The land use that is most affected by erosion and accretion in the coastal area of the Rebana metropolitan area is fishpond.