Kinematic wave parameters and time of travel in circular channel revisited

Two cases are considered: (a) circular channel with constant Manning roughness coefficient, and (b) circular channel with variable Manning roughness coefficient. For case (b), a mathematical equation, which can describe the variation of Manning roughness coefficient with flow depth is presented. The examination of the “old” kinematic wave parameters shows that they do not give good agreement to the “true” relationships between discharge and flow area. “New” kinematic wave parameters that give better agreements are recommended to replace the old parameters. Similarly, the time of travel formulas that are based on the new parameters are recommended to replace the formulas that are based on the old parameters. These time of travel formulas can be used for estimating the time of travel in circular channel subject to a uniform lateral inflow and a constant upstream inflow.