Impact of climate variability on IDF curves and design discharges: the august 2023 event in SloveniaEastwood, Cathryn (Avtor) Šraj, Mojca (Mentor) Bezak, Nejc (Komentor) master thesisintensity-duration-frequency (IDF)GumbelSloveniaextreme precipitationdesign dischargeaugust 2023 floodThis study investigates the impact of climatic variability, particularly the August 2023 extreme flood event, on intensity-duration-frequency (IDF), depth-duration-frequency (DDF) relationships and design discharge estimates in Slovenia. Precipitation data from 25 rain gauges distributed throughout the country, at five-minute resolution, were used to derive an Annual Maximum (AM) series, which was analyzed to assess non-stationarity, identify the most appropriate theoretical distribution, and derive IDF curves including and excluding 2023 data. These curves were compared with national IDF/DDF datasets from the Slovenian Environmental Agency (ARSO) and the CROSSRISK project to assess their continued validity, and used as input to a rainfall-runoff model of the Suhodolnica catchment to assess the influence of the August 2023 event on design discharges. Standard and regional Mann-Kendall trend testing revealed limited evidence of non-stationarity, although a slight upward trend in long-duration extremes was detected in the Temperate Continental climate region. RMSE and MAE identified the Gumbel and Log-Pearson Type III distributions as best-performing across the gauge network. Incorporating the 2023 event increased calculated rainfall intensities at stations most affected by the flood, and a comparison with existing datasets revealed that ARSO curves, based on less recent data, are not fully representative of current climatic conditions. The representativeness of CROSSRISK curves could not be disproven. The rainfall-runoff model showed that incorporating 2023 data into design storm inputs increased simulated peak discharge by roughly 5 - 8%, depending on return period and antecedent conditions. These findings support more frequent, transparent updates to IDF and DDF datasets to improve infrastructure resilience.[C. Eastwood]20262026-09-01 08:48:47Magistrsko delo/naloga186405UDK: 556.166:551.583(497.4)(043.2)VisID: 181514COBISS_ID: 289783043sl