Based on the isovel contour that was first introduced by Maghrebi (2006) and the geometrical parameters of channel cross sections such the cross-sectional area, wetted perimeter and the width of the free surface, Maghrebi [13] introduced a stage- discharge relationship. The main purpose of this paper is to use the Maghrebi's method in estimation of the conveyance of channels and employing it in 1-D numerical model based on the energy equation such the stander step method for evaluating water surface profiles. Thence, published field measurements of M1 and M2 water surface profiles by Sadiq and Sturm (1996) are used, and a comparison is made between water profiles of the proposed model and the ones of HEC-RAS and CES. The results show that 1-D modelling combined with the Maghrebi's method gives reasonable accurate values. In some cases, the results of this method are better than the ones of HEC-RAS and CES.

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