Spatio-temporal Variability of Hydraulics and Morphodynamics in a Small River

Abstract Fluvial systems are formed through hydromorphological processes, which describe the interaction between the flow characteristics and the sediment across the river. Continuous hydromorphological processes promote alteration of river courses through changes in planforms, as rivers try to balance between the sediment transport, capacity of the water and the sediment supply. Thus, the fieldwork investigations on hydraulics and morphological changes along the Melana River in Pulai, Johor Bahru were carried out. Three measurement sections were chosen as spatial variables, while intervals of 7 day(s) and 21 day(s) were chosen as temporal variables in this study. Hydraulic parameters such as water level, velocity distribution, and morphological changes along the river were examined. The findings prevailed that significant temporal and spatial variability in bed morphological changes were driven by hydraulic factors such as water level, flow velocity and also channel planform itself. The highest bed load transport was observed at S3 with 2.13 g/s, meanwhile the lowest rate of bed load transport happened at S1 with 0.53 g/s. The most noticeable changes in bed morphology were observed at downstream section of river with deepened up to 2.27%. Variations in river width and depth created differential flow velocities, impacting the erosion and deposition patterns.