Discharge can be considered one of the most essential hydraulic parameters to know about a river for managing it. Ordinarily, the H-Q equation is used to estimate the discharge from the level of a river. Certainly, this provides acceptably accurate estimates in the upper reaches of rivers. In estuaries, however, its accuracy is fatally degraded. In the initial part of this study, a river was divided into 15 zones in the traverse direction, and the discharge in each zone was compared with the actual discharge of the river itself to see what kind of cross section allowed the local discharge to show the best correlation with the river discharge. Then, ADCP were placed on the riverbed and longterm measurements of the flow speed distribution were taken for comparison with the discharge as indicated by actual measurements. A clear proportional relationship was obtained between the two sets of data. It is clear that the equation relating the data sets provides a far superior estimate of discharge over the H-Q equation.