Study of the seasonal and interannual shoreline changes in Pesaren Beach, North Bangka, Indonesia

Abstract

Coastal villages at Bangka Island have seen severe erosion that endangers their livelihood and infrastructure, likely to be induced by climate changes and human activities. Only a few studies have attempted to investigate the shoreline dynamics at Bangka Island, making this issue is still poorly understood. This paper presents a case study at Pesaren Beach, located in the Northeast of Bangka Island. The seasonal and interannual shoreline dynamics of Pesaren Beach are investigated by combining numerical hydrodynamic modelling using Delft3D and long-term satellite images and offshore wave analysis. Shoreline dynamics obtained using CoastSat reveal a cyclical pattern influenced by seasonal variations of the wave. During the northeast monsoon period (DJF), the strong and northern wave induces a receding shoreline. Meanwhile, during the west monsoon period (JAS), weaker and southeastern waves form a beach recovery period, advancing the shoreline. Tidal currents are less likely to contribute significantly to this seasonality, with spring peak flow speed < 0.5 m/s. The yearly fluctuations of shoreline position appear to be attributed to the interannual variability of wave climate. These results provide valuable insights into Pesaren Beach and lend a baseline understanding of other embayed sandy beaches on Bangka Island. Furthermore, this study demonstrates the potential of using publicly available data and tools to investigate shoreline dynamics in data-scarce regions like Indonesia. Built on this study and supported by field measurement, the potential impact of offshore tin mining on the beach could be explored.