Study of Sediment Land Elevation Dynamics Using Airborne LiDAR in the Ajkwa Estuary, Mimika, Papua, Indonesia Pratama S.A.P. , Pramadarsah A. and Helmi M.
Department of Oceanography, Faculty of Fisheries and Marine Sciences, Universitas Diponegoro, Indonesia
Environmental Division, PT Freeport Indonesia, Mimika, Papua, Indonesia
Abstract
Estuarine environments are highly dynamic due to tidal activity and sediment input from rivers, often causing rapid elevation changes. The dynamic changes in the Ajkwa Estuary due to rapid sedimentation require a comprehensive and well-structured programme aimed at enhancing ecosystem services, which provide ecological benefits and support local livelihoods. This initiative seeks to establish a sustainable and harmonious estuarine environment through spatial planning, particularly by organising mangrove zones as integral elements of an ecologically, socially, and sustainably valuable landscape. This study examines elevation changes and the role of geo-tube and e-groin (bamboo structures) in enhancing sedimentation. Airborne LiDAR data from 2017, 2019, 2022, and 2024 were processed into digital elevation models (DEMs), and elevation change was analysed using the DEM of Difference (DoD) method within the Geomorphic Change Detection (GCD) tool. Although the DoD method has been used elsewhere with DEM data, its application in estuarine areas remains limited. This study enhances estuary monitoring by applying the method in a dynamic coastal system supported by LiDAR technology. Results show elevation loss between 2017 and 2019. From 2022 to 2024, after installing sediment management geo-tube and e-groin (bamboo structures), intervention areas recorded gains 99.49% in Area A and 93.91% in Area B, while the non-structured area showed a more stable pattern. The findings confirm that sediments transported into the ModADA area can accumulate effectively with the aid of geo-tube and bamboo structures, making them suitable for mangrove planting and contributing to sustainable estuary management.
Keywords: Ajkwa estuary, geomorphic change detection (GCD), digital elevation model (DEM), LiDAR, DEM of difference (DoD)
