ABSTRACT
Presence of surface bedform in the form of stable clast is believed to be exist at micro-scale. Stable clast is believed to modify the flow field and provide sink and source for incoming sediment particles. The dynamics of flow pattern and bed load rate in the presence of stable clast are always puzzling due to wide range of particle size and presence of roughness elements. Thus, this issue can be treated using two methodological approaches namely local scale and reach scale solutions. Incorporating the flow fields and turbulence statistics at a very local scale leads to the prediction of occurrence of bed load transport using probability approach. Bed load and turbulence data were physically measured at mountainous region having diverge surface bedform in its presence. Understanding transport occurrence at finer scale is vital for instream rehabilitation, river restoration and installation of sediment sampler on river beds. However, treating the dynamics of flow and bed load at reach scale is significantly differed from local scale approach. Transport of sediment in the presence of stable clast at reach scale is best equipped using continuous transport prediction or reach-averaged bed load model. Wide ranges of data from King et al. (2004) are used for further investigation at reach scale solution. The presence of stable is verified from previous report and morphodynamic analysis. Transport of sediment using existing prediction model postulate the less suitability and a need for modification. Thus, a similarity approach is used to develop the bed load model which can predict the bed load transport at reach scale. This new equation is successfully predicting the transport of sediment in the presence of stable clast. This equation alleviates the dependence on wide range of particle size as previously demonstrated by past model.
