Flood volume estimation in Switzerland using synthetic design hydrographs a multivariate statistical approach

Manuela Irene Brunner, Olivier Vannier, Anne-Catherine Favre, Daniel Viviroli, Paul Meylan, Anna Sikorska and Jan Seibert,

Accurate estimations of flood peaks, volumes and hydrographs are needed to design safe and cost-effective hydraulic structures. In this study, we propose a statistical approach for the estimation of the design variables peak and volume by constructing a synthetic design hydrograph. Our approach is based on fitting probability density functions to observed flood hydrographs and takes the dependence between the two variables peak and volume into account. The method consists of the following six steps: sampling of flood events, baseflow separation, normalization of the hydrographs, fitting of the hydrographs with statistical density functions, modeling of peak and volume considering their dependence, and construction of the synthetic design hydrograph. The method was developed and tested based on data from nine meso-scale catchments in Switzerland, and has been shown to provide reliable synthetic design hydrographs for all of these catchments. While the method has so far been applied to gauged catchments, it is foreseen to make it applicable to ungauged catchments using regionalization approaches.

2016/1 468-476