The Evidence of Coastline Changes in Banten Bay, Indonesia

Consisting of semi-circular body, coastal region in the Banten Bay holds a significant role for both marine ecosystem and human activities. The change of its coastline due to the erosion/sedimentation process may affect the ecosystem and economic purposes. This study aims to figure out the evidence of coastline changes in Banten Bay using remote sensing and numerical model. The recording satellite data from Landsat 5 TM, Landsat 7 ETM+ and Landsat 8 OLI during 1990 - 2019, are employed to examine the coastline changes using Normalized Different Water Index (NDWI). Besides, applying the Langevin equation in the particle tracking model, the sediment data from observation in April 2016 are utilized to simulate the trajectory of sediment movements to understand the hydrodynamic processes which cause the changes of coastline. Over 30 years, satellite imageries showed the significant changes with the average of 0.8 (sedimentation) and 0.5 (erosion) km for the western and eastern part respectively. The simulation of sediment movements illustrates the dominant westward direction with the maximum 247.88 m3/day supporting the sedimentation in the western part. Moreover, the distribution of suspended sediment demonstrates the highest concentration in the eastern part with the range 9.47 - 249.54 mg/L indicating the evidence of intense erosion in the eastern part. HIGHLIGHTS Analysis based on satellite imageries and sediment transport model simulation have been carried out to give the evidence of coastline changes in Banten Bay Satellite imagery confirmed that the dominant change occurred in the western and eastern part of the Bay with the average of 0.8 km and -0.5 km, suggesting sedimentation and erosion respectively Model simulation results revealed that the sediment moves westward with the maximum 247.88 m3/day in the western part and high suspended sediment concentration with the range 9.47 - 249.54 mg/L in the eastern region GRAPHICAL ABSTRACT