Regional Flood Frequency Analysis of the Sava River in South-Eastern Europe

Regional flood frequency analysis (RFFA) is a powerful method for interrogating hydrological series since it combines observational time from several sites within region to estimate risk-relevant statistical parameters with higher accuracy than single-site series. Since RFFA extreme value estimates depend on the shape of selected distribution data-generating stochastic process, there need suitable goodness-of-distributional-fit measure in order optimally utilize given data. Here we present novel, least-squares-based select optimal fit set five distributions, namely Generalized Extreme Value (GEV), Logistic, Gumbel, Log-Normal Type III and Log-Pearson III. The metric applied annual maximum discharge six stations along Sava River South-eastern Europe, spanning years 1961 2020. Results reveal that (1) basin can be assessed as hydrologically homogeneous (2) GEV provides typically best fit. We offer hydrological-meteorological insights into differences among stations. For period studied, almost all exhibit statistically insignificant trends, which renders conclusions about risk relevant sciences design regional protection infrastructure.