Study on river-discharge measurements with a bottom-mounted ADCP

To examine the accuracy of discharge measurements in rivers, continuous measurements of flood flows were conducted with a bottom-mounted ADCP. The observed data indicates that the vertical distribution of the velocity varied considerably in the rising and falling stages of a hydrologic event, in which the unsteadiness parameter alpha and H.WL. were relatively larger. It should be noted from the observed data that the averaged coefficients of float were in good agreements with well-known empirical values, while the coefficients of float varied appreciably in each hydrologic event. The accuracy for evaluating river discharge is investigated by using the rating curves with H-Q and V-Q, showing that the rating curves with H-Q and V-Q are appropriate for the evaluation of discharge in the upper and lower reaches of the river, respectively.