Application of an improved linear storage routing model for the estimation of large floods

A runoff routing model, which incorporates a linear routing structure and attempts to provide a physically realistic distribution of storage effects, has recently been developed. The model with its physically realistic storage effects has been shown to provide consistently good reproduction of observed large floods without the need for parameter fitting or calibration. Storage distribution is determined from a volume law that accounts for the distribution of river channel storage in natural catchments. The model is briefly described, but the emphasis is on demonstrating its ability to reproduce large observed floods and design floods in China and Australia. The model results are compared with those from two commonly used non-linear storage routing models using several measures of performance. The probable maximum floods (PMFs) estimated based on all three models are also compared. The linear model using the proposed volume law is recommended for estimation of design floods because it has been shown to represent the observed geomorphological processes more realistically than other models, and because it reproduces observed large floods at least as well as the other models considered in this study.