DISCUSSIONS ON MODELLINGS OF BED INTERSTITIAL ZONES AND BED LOAD INCIPIENT MOTIONS IN COBBLE BED RIVERS WITH PARTICULAR REFERENCES ON BED-MATERIAL PARTICLE SHAPES

Abstract

Conventionally, the particle shape of bed-material has not been taking into account the modelling of channel bed with sediment transport in the fields of fluvial hydraulics and environmental management. The objectives of this study is to check the effects of particle shape not only on the sediment transport process, but also on the bed interstitial zone as a condition of habitat environments.

Firstly, it is examined whether the bed-material particle shapes are characterized as the properties of channels and their watersheds or not. Secondly, it is described that the bed interstitial zones are formed due to the difference of particle shapes. And then, the critical tractive force on bed load incipient motion could be reevaluated by using the classical hydraulic modelling with ellipsoidal particle approximated by its tri-axial lengths, finally.