Estimation of The Relationship Between The Travel Time of Flood Peaks and Peak Discharge on The Poprad River by Multilinear Flood Routing

The empirical relationship between travel-time of flood peaks and peak discharge was studied on a reach of the Poprad River in Slovakia. The data were fitted by regression and compared with the expected shapes as described in the literature. Further a chain of linear segments has been considered as the model of that relation. The number of segments parameters and the angles between theses in this piecewise linear model were fitted by optimisation of a conceptual multilinear flood routing model performance on a large flood wave with the help of a genetic algorithm. In the setup of the multilinear model the travel-time parameter of the model was allowed to vary with discharge according to the piecewise linear model of the travel time of flood peaks. The discrete state space representation of the Kalinin-Miljukov model was used as the basis for a multilinear discrete cascade flood routing model. The resulting relationship was compared with empirical data on travel times and used to model the variability of the time parameter in the discrete state space representation of the Kalinin and Miljukov model on three verification floods. The modelling results showed that the inclusion of empirical information on the variability of the travel-time with discharge even from one flood enables satisfactory accuracy for the prediction of the flood propagation process