| Abstrak/Abstract |
This study investigates the spatio-temporal bathymetric changes and classifies seabed morphology in Pangpang Bay, Banyuwangi, Indonesia. As a vital conservation and aquaculture area, understanding its seabed dynamics is crucial for sustainable management. The objective of this research was to analyze bathymetric changes from 1984, 2021, and 2024 and to classify the seabed morphology in 2024. This is the first multi-temporal mapping study to integrate historical nautical charts with high-resolution Single Beam Echosounder (SBES) data for Pangpang Bay, offering a novel perspective on its long-term coastal dynamics. The methods involved obtaining bathymetric data from historical nautical charts and single beam echosounder surveys. Spatial interpolation techniques were used to construct 3D bathymetric models. We performed cut-and-fill analysis, cross-sectional profiling, and depth variation detection to quantify changes. Seabed morphology was classified based on established hydrographic standards from the International Hydrographic Organization (IHO) as well as on previous research. The results show significant changes in the bay’s seabed. Sediment accumulation from 1984 to 2021 was 580,630.07 ± 91,551.20 m³, which was greater than the accumulation from 2021 to 2024. Conversely, erosion during 2021–2024 exceeded the earlier period by 6,811,950.01 ± 372,259.48 m³. Based on these findings, we conclude that the seabed morphology of Pangpang Bay is characterized by a high degree of geomorphological diversity. We found that sediment input, likely from river discharge and mangrove coverage in the western part of the bay, has led to channel narrowing. In contrast, we believe that increased flow velocity in the eastern part contributes to erosion, resulting in the formation of a V-shaped valley. The general-scale classification identified three types of morphology—plane, slope, and escarpment—while the more detailed-scale mapping revealed a wider variety of features, including break in slope, bank, sill, depression, and gully, as well as the previously mentioned plane, slope, and escarpment. These findings are crucial for informing marine spatial planning and coastal management strategies in Pangpang Bay, particularly for conservation and aquaculture activities. |
