Development of regression equations for the water discharge estimation in tidally affected rivers

In the gauging station which tidal current effects are dominant, the reliable measuring methods are needed. In this study, the stage height difference is considered to derive the rating curve and the index velocity is considered to derive the mean velocity equation which discharge results from these equations are compared with the measured discharge collected in the Samrangjin station where tidal current effects are dominant. A robust minimum covariance determinant method, one of the nonlinear multi-regression methods, is applied to derive regression equations for the rating curve and mean velocity equation using 39 measurements collected at Samrangjin gauging station. The new rating curves allow superior in predicting discharge more precisely in tidily affected river as compared to existing equation. The discharge estimated using the mean velocity from the index velocity is in best agreement with the measured discharge data.