A method for dealing with the effects of cross-sectional shape on flow resistance in open channels was developed and presented in a previous paper. The new method, which was referred to as Kazemipour's method, was tested against the experimental data of other investigators available at the time when it was developed and published. Later, it was decided to carry out further experiments to obtain a new and independent set of data in smooth rectangular channels and to test the effectiveness of Kazemipour's method on these new data.