Discussion of “ Development and Verification of an Analytical Solution for Fore - casting

The author presents an interesting method to forecast nonlinear kinematic flood waves (Serrano, 2006). As a first remark, the discussers would like to stress the fact that the proposed method is an approximate solution and not an analytical solution, as suggested by the title of the paper. Indeed, an analytical expression is given by the backwards characteristics methods, as in Eq. (6) of the paper. However, since this solution is implicit, the author proposes an approximate explicit solution by making simplifying assumptions. The discussers would like to raise two points in this discussion: