ASSESING THE PREDICTABILITY OF TOTAL SEDIMENT TRANSPORT RATE FOR UNIT STREAM POWER APPROACH

Abstract

Sediment transport is a significant factor in effective design of hydraulic structures and open channel water conveyance. Estimation of the
amount of sediment material w hich a specific flow can carry is one of the major issues of sedimentation research. Unit stream power is defined as the
time rate of potential energy per unit weight of water, and is found to be the dominant factor in the determination of total sediment concentration being
carried by the (Yang, 1972). Yang’s (1979) unit stream power approach for total load sediment transport function is applied to test the predictability of
total sediment transport rate by using flume data sets of Samaga et al (1986), Willis et al (1972) and river data set of Middle Loup river of Hubbel et al
(1959). The performance of the Yang’s sediment transport function for different data sets has been evaluated by finding statistical parameters, such as
root mean square error (RMSE), discrepancy ratio and inequality coefficient. From the evaluation, it is observed that the Yang (1979) total load function
under predicts the sediment transport rate for the three mixtures M1, M2, M3 and predicts well for mixture M4 of Samaga et.al data set giving good result
compared to other mixtures. For both Willis et al (1972) data set and the river data of Hubbel et al (1959) total load function of Yang (1979), both under
predicts as well as over predicts sometimes.Yang total load equation gives better results for samaga et al (1986) data sets for the four mixture.