Discharge estimation in wide meandering compound channels: Fid-Bau Portal

Discharge estimation in wide meandering compound channels

Mohanty, P.K. / Mohanty, L.P. / Khatua, K.K.

A model for stage–discharge relationship in two-stage wide meandering channels, devised by statistical analysis of new experimental boundary shear data and some published shear data, is presented. By evaluating the measured boundary shear percentage on floodplains of unequal length on either side along with corresponding wetted area percentage for sinuous channels, it is seen that different but particular empirical relationships exist between shear percentage and percentage flow area due to various flow mechanisms occurring on floodplains lying on either side of the bend. The empirical relationships obtained for left floodplain shear is an exponential function while that for total floodplain is a power function. Expressions for average zonal velocity and hence for zonal discharge are then estimated by 1D analysis to compute the H–Q rating curve for such channels. This method is validated through its application to different published data sets with discharge prediction error lying close to ±10% on most occasions. The method when compared with some other well-known 1D approaches is found to perform reasonably well as evident from error analysis. The method when tested for predicting flow distribution, the error percentage is again within 10% for available limited data series.