Author(s): Yusron Saadi; Ida Bagus Giri Putra; Agus Suroso
Linked Author(s):
Keywords: Bed surface stability; Steady antecedent flow
Abstract: Bimodal sediment beds were exposed to different duration of steady antecedent flow hydrographs. The works were intended to observe the changes in bed topography after a certain duration of exposure by the flow. The changes in bed surface structure were observed by measuring the elevation of the bed surface at a large number of points organized on the orthogonal grid. Probability distributions of bed surface elevations were carried out to estimate the level of changes and the variations of bed surface level. The results suggest that the pattern of bed surface topography after steady flow hydrograph of 6 and 9 hours tended to form diagonal patches. Different bed surface formation than that in the original bed became apparent, particularly elongated valleys and peaks were established in the measurement area. Different patterns were produced by 12-hour steady flow hydrograph with the concentration of eroded bed in certain areas and the patches were more elongated in the streamwise direction. The level of stability formed by the different duration of steady flow is also reflected by the distribution curves after stability test. The difference between the distribution curves was easily recognized in the shorter duration and decreased in the longer duration of the hydrograph. Only bed surface elevation distribution around the mean level changed whilst the bed surface elevation at the higher values above and below the mean level did not deviate markedly.
Year: 2018