Regional frequency analysis of the maximum 5-day precipitation in Slovakia using L-moment approach

Understanding the patterns of extreme precipitation is crucial for effective water resource management, infrastructure design, and flood risk assessment. This study offers a comprehensive analysis of the maximum annual 5-day precipitation totals (Rx5d) in Slovakia using regional frequency analysis (RFA) to elucidate the probabilistic behavior of these events, essential for informed decision-making amid changing climate patterns. We analyzed 70 years (1951–2020) of precipitation data from 419 stations employing the L-moments approach for regional homogeneity testing and frequency analysis. The data were stratified into homogeneous regions using a multi-regression approach and distance matrices, facilitating the development of regional frequency curves. We employed L-moments ratio diagrams and Anderson-Darling goodness of fit tests for extreme-value distributions. Our methodology delineated 14 distinct regions, with the generalized logistic distribution identified as the most suitable approximation for Rx5d in 11 out of the 14 clusters. The study suggests that cluster analysis coupled with L-moments-based regional frequency analysis can effectively derive design rainfall estimates for Slovakia. The developed regional frequency curves are invaluable for estimating return periods of extreme 5-day precipitation events at any location within the study area, proving indispensable for effective flood risk management, infrastructure design, and climate adaptation planning.