Establishing baseline conditions of fine sediment dynamics using an unmanned aerial vehicle

Understanding sediment dynamics is fundamental for river management, ecological sustainability, and hydropower development. Establishing reliable baseline conditions of sediment loads is crucial, especially in tropical river systems where hydropower development is rapidly expanding, and where knowledge gaps remain compared with temperate regions. Recent advances in remote sensing have provided new possibilities for sediment research. In the Baleh river, Sarawak, Malaysia, drone-based analyses revealed striking contrasts in suspended sediment concentration within confluence zones, sometimes varying significantly over just a few metres. Such spatial detail highlights the effectiveness of unmanned aerial vehicles (UAVs, or drones) in identifying hotspots of sediment mixing, documenting tributary-mainstem interactions, and enhancing baseline data collection of the Baleh river.