New method for estimation of stage-discharge curves in natural rivers

In the presented paper, a simple and feasible method for estimation of stage-discharge relationship in natural rivers using the concept of discharge estimation based on single point velocity measurement is introduced. Two innovative techniques have been implemented in rating curve estimation. First, discharge at a certain stage can be estimated by velocity measurement at an arbitrary point in the flow cross section. Then a relationship between the parameters obtained by the single point measurement technique and discharge ratios at different stages is presented. For this purpose, a relationship based on dimensional analysis through minimization of the differences between the calculated and analytical discharges at two different stages is established. For the verification, the results of the proposed relationship are compared with the observed stage-discharge data taken from the Severn River in UK, the Cuenca and Tomebamba rivers in Ecuador. The results have shown the high accuracy of the proposed method in such a way that the maximum relative errors for the Severn, Cuenca and Tomebamba rivers are less than 3%, 6% and 3%, respectively. In estimation of stage-discharge relationship, if the referenced stage is taken from higher stages, maximum error will be reduced to much smaller values.