The Influence of Flood Discharge to the Stability of River Morphology

Sedimentation has been an issue for a long periode of time. It affects the river morphology process which is constantly changing from time to time due to its sediment supply system. There are 2 main parameters that strongly affect the morphological process and those are discharge and sediment. When the movement of the sediment occur it will lead to degradation and agradation along the river that will affect the river morphology. Because of those processes, the river dynamic characteristic should be considered in structural design.In North Sulawesi, Tondano River has been known as one of the main river and it has a discharge all year around. With rapid land coverage change, dicharge may increase significantly and hence more sediment could be transported. Moreover, there are increase use of the river resources and more structures built along its sides that appeared to have induced more sediment in transport.This paper presented the corelation between discharge of various flow rates and the amount of sediment being transported at these rates along certain river segments. Slight changes on morphology of the river due to degradation and agradation processes at these segments were also displayed Analysis was carried out to evaluate agradation and degradation processes during various flow rate at the middle section of the Tondano River. Prior to this was the analysis of river discharge. This research has confirmed that indeed the sediment transport occurred at the observed river’s segments was due to the varied discharges. The transport therefore instigated the recurrent changes on the river’s morphology this may pose threats to the stability of river’s structures i.e. by means of scouring progression. Solutions suggested to overcome the problem includes: 1). Non-structural or structural reinforcement on the river bank; and 2). Sediment management to overcome the degradation and agradation processes.