Abstract

Employing total bed material load equations which were derived from non-native hydraulic and sediment databases often yields an undesired prediction. Furthermore, the performance of such equation also depend on the river characteristics which the equation was derived such as energy gradient, channel width, discharge, velocity, sediment particle size and etc. Thus, one should always bear in mind that the performance of existing sediment transport equations may inconsistence from region to region and from river to river. Thus, there is an urgent need to come out with a site specific sediment transport equation which may yields better results for high gradient rivers in Malaysia. This paper reports the preliminary results on the development of a new total bed material load equation that is applicable for high gradient rivers in Malaysia by using multiple linear regression analyses. The hydraulic and sediment data were collected from 6 high gradient rivers having diverse catchment characteristics in Malaysia. The governing parameters were carefully selected based on literature survey and field experiments, examined and grouped into five categories namely mobility, transport, sediment, shape, and flow resistance parameters. The most influential parameters from each group were selected by using all possible regression model method. The suitable model selection criteria namely the R-square, adjusted R-square, mean square error, and Mallow’s Cp statistics were employed. The accuracy of the derived model is determined using the discrepancy ratio, which is a ratio of the calculated values to the measured values. The best performing models that give the highest percentage of prediction from the data were chosen.

Keywords: Sediment Transport, High Gradient Rivers, Multiple Linear Regressions