Sediment transport rate and bed formation in straight compound channels

Abstract

Researches on compound channel hydraulics have been carried out for many years, yet few are concerned with sediment transport. In order to prevent sediment problem, the sediment transport process and the influence of bed form on the roughness of the river flows must be understood. An experimental investigation on the flood flow characteristics and sediment transport in straight compound channel have been undertaken. The effects of mobile-bed channels on flow characteristics and sediment transport were studied by using flumes in the Hydraulics and Hydrology Laboratory, Faculty of Civil Engineering, UniversitiTeknologi Malaysia (UTM). The flume is 4.0 m long, 0.6 m wide and configured into a 0.3 m wide and 0.05 m depth of rectangular main channel with a single floodplain. A mobile-bed channel is composed of uniform graded sand with a d of 0.8 mm. The findings on sediment transport rateand bed formation of the bed channel for overbank 50 flows in straight rectangular compound channels are presented in this paper. It has been found that the maximum velocity zone is observed to be in the main channel where sediment transportation takes place. Thus, the bed formation change after the sedimentation and erosion occur at the channel bed which is also influenced by the higher velocity in the main channel.