The discharge estimation that means the most important element in a wetlands ecosystem and rivers is a
prime concern. All the interim, this discharge estimation depends on stage-discharge curve, but the limitation of
stage-discharge curve that uses only connection between the stage and discharge is widely well known. Thus, this
paper proposed a method of discharge estimation in a section through "representative parameter estimation method"
by using Manning and Chezy equations that have been extensively used in an open channel. Each result is
presented by both RMSE and Discrepancy Ratio. The scale difference for the results between laboratory and natural
open channel data existed, but the each result showed that the estimated discharge agree with the measured
discharge. If the verification and improvement are conducted in various rivers through continuous study, the easy
and rapid discharge estimation will be possible. So, the proposed method will be utilized in the water resources
fields.