Hydrological regionalisation of flood frequency analyses in Slovenia

Abstract

Floods in Slovenia are becoming more and more frequent and are cause of the third highest damage due to \ud natural disasters. The basis of effective flood risk management is a reliable frequency analysis that can be \ud used for estimating event return period. An upgrade of the classical frequency analysis is the regional flood \ud frequency analysis. Its main advantage is that it allows higher accuracy of flood forecasts also in areas with \ud shorter or no measurements. Regional flood frequency analysis encompasses four steps: checking\ud the \ud accuracy and discordance of data, identification of homogeneous regions, choice of an appropriate frequency \ud distribution for a region, and quantiles of the selected distribution. The most challenging part of this analysis \ud is the identification of homogeneous hydrological regions. In this paper we present three methods that can be \ud used for this step. The regional flood frequency analysis was performed for selected water gauging stations \ud in Slovenia