Probabilistic regional envelope curves in Europe

Regional envelope curves represent the current level of information about the most extreme flood events observed in a region. In this study, we derive and compare regional envelope curves across European regions, with a multi-scale approach. A large flood database, containing more than 7000 annual maximum discharge series from gauges located all over Europe, is used for the analysis. Multiple spatial scales are adopted to take into account the uneven gauge density in the study domain. In each region, we derive the slope of the regional envelope curve and the envelope flood for a representative catchment of size 1000km2. Based on the framework of probabilistic envelope curves, we also make a probabilistic statement about the regional envelope curves in terms of its return period. Results show that the slope of the regional envelope curves varies substantially across European regions and the correlation between envelope flood and the estimated return period is investigated.