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Highlights from the article: In 2019, the Faculty of Civil and Geodetic Engineering of the University of Ljubljana (UL FGG) is celebrating its centennial: The precursor of the faculty was the Technical Faculty established in 1919 as one of five founding faculties of the university. In the field of capacity building, UL FGG offers several courses for graduate and postgraduate students in landslide mechanics and dynamics, landslide stabilization and landslide risk mitigation. IPL-151 Soil matrix suction in active landslides in flysch - the Slano Blato landslide case (2010-2012) (Mikos et al. [23]; Macek et al. [12]) 31 Pulko B, Majes B, Mikos (2013) Reinforced concrete shafts for the structural mitigation of large deep-seated landslides: an experience from the Macesnik and the Slano Blato landslides (Slovenia).

In some rainfall-triggered landslides, intensity-duration thresholds can have limited prediction ability; therefore, investigation of alternative approaches that can be used for temporal prediction of rainfall-induced landslides is needed. This paper presents a methodology for predicting rainfall-induced shallow landslides based on a lumped conceptual hydrological model. The production storage level during the rainfall event and the rainfall sum during the event are used for landslide prediction. Based on these two hydro-meteorological variables a threshold is defined that could be used for rainfall-induced landslides prediction as part of an early warning system. The presented methodology is tested using the meso-scale Selška Sora River catchment case study in western Slovenia where 20 active landslides from the Slovenian National Landslide Database are used to calibrate and evaluate the methodology performance. The results are compared to three different (i.e. local, regional, and global) intensity-duration thresholds. The results of the presented approach are superior in terms of several goodness-of-fit criteria compared to tested local and global ID thresholds. Because only daily rainfall, evapotranspiration, and discharge data are needed to calibrate the selected hydrological model and only daily rainfall and evapotranspiration to run the model, the presented approach could also be useful for data-scarce areas where detailed physically based landslide prediction models that require many data cannot be constructed. Moreover, we have also derived the probabilistic version of the proposed threshold for triggering of shallow landslides using copula functions. [ABSTRACT FROM AUTHOR]

High-frequency rainfall data is needed in different practical hydrologic applications, such as the construction of the intensity-duration-frequency curves (IDF). This paper presents an investigation of trends (station-wise and regional) for several rainfall durations that were constructed based on the 5 min rainfall data. Moreover, changes in IDF results for two 22-year sub-samples were also analyzed. Additionally, changes in extreme events clustering at the regional scale were also analyzed. Ten rainfall stations (44 years of data 1975–2018) located in Slovenia (central EU, approx. 20,000 km2) were used in this study. Results indicate that no clear pattern in the detected trends can be found based on the analyzed stations. However, all the statistically significant trends at the significance level of 0.05 for the 5 min rainfall data were negative. Moreover, regional trends for this duration were also statistically significant. The changes in the design rainfall events between two equal sub-samples (1975–1996, 1997–2018) were between −30% and 60%. The investigation of changes in extreme rainfall event clustering indicated that extreme 5, 30, and 60 min events could more frequently occur a few days earlier in spring or summer compared to the past period. On the other hand, longer duration events (i.e., 360 and 720 min) tend to more frequently occur a few days later in autumn compared to the past. In most cases, changes are not statistically significant. [ABSTRACT FROM AUTHOR]

Summary Floods, landslides and debris flows are natural events that occur all over the world and are often induced by extreme rainfall conditions. Several extreme events occurred in Slovenia (Europe) in the last 25 years that caused 18 casualties and approximately 500 million Euros of economic loss. The intensity–duration–frequency (IDF) relationship was constructed using the Frank copula function for several rainfall stations using high-resolution rainfall data with an average subsample length of 34 years. The empirical rainfall threshold curves were also evaluated for selected extreme events. Post-event analyses showed that rainfall characteristics triggering flash floods and landslides are different. The sensitivity analysis results indicate that the inter-event time definition (IETD) and subsample definition methodology can have a significant influence on the position of rainfall events in the intensity–duration space, the constructed IDF curves and on the relationship between the empirical rainfall threshold curves and the IDF curves constructed using the copula approach. Furthermore, a combination of several empirical rainfall thresholds with an appropriate high-density rainfall measurement network can be used as part of the early warning system of the initiation of landslides and debris flows. However, different rainfall threshold curves should be used for lowland and mountainous areas in Slovenia. [ABSTRACT FROM AUTHOR]

Extreme events such as flash floods and debris flows are frequent phenomena that occur in steep torrential catchments; these kinds of events can cause notable geomorphic changes. Repeated terrestrial laser scanning (TLS) surveys were performed in a steep forested catchment of the Kuzlovec torrent (drainage area ~ 0.7 km 2 ) in central Slovenia, where a ~ 200-m long section of the torrent was scanned in 2013, 2014, and 2015. The main aim of this study was to perform the geomorphic response detection in the torrent due to hydro-meteorological events of different magnitudes. After applying several pre-processing steps, digital terrain models (DTMs) with a cell resolution of 5 cm were produced. The geomorphic change detection was performed using the DTM of Difference approach (DoD). Several above-average flow events occurred in the period from 2013 to 2015 (some of them can be regarded as floods). The 2014 August extreme flash flood that was initiated by the rainfall event with a return period exceeding 100 years, where maximum 1-minute rainfall intensities were up to 288 mm/h, led to erosion rates of an order of magnitude higher than average annual erosion rates. Moreover, the analysis of the geomorphic changes shows that the August 2014 flash flood caused intense sediment transport processes that resulted in the changes at the location of the main stream channel thalweg and reduced channel roughness. The unit stream power for the scanned section of the torrent was assessed to be approximately 500 W/m 2 during this extreme event. This is above the thresholds that were suggested to differentiate between the situations where significant geomorphic changes can occur and the situations where geomorphic changes are not notable. [ABSTRACT FROM AUTHOR]

Summary: Rainfall kinetic energy–intensity relationships for rainfall erosivity estimation were established on the basis of raindrop size distribution measurements performed in the Brkini hilly area in southwest Slovenia, a transitional area between the Mediterranean and continental climate conditions. A set of measurement instruments, an optical disdrometer coupled with a rain gauge, was installed on two locations: Koseze and Kozjane. The data set contained raindrop size distribution and rainfall intensity measurements of the rainfall events that occurred during a one-year period in the 2008/2009 season. The rainfall intensities obtained with the rain gauges were used for event rainfall depth control measured by the disdrometers and testing the established kinetic energy–intensity (KE–I) relationships. Two exponential KE–I relationships were established for each measuring site, for 1-min and 5-min rainfall intensity data, respectively. Their performances were tested and compared with the performances of other KE–I relationships proposed by authors throughout the world, which could be recognised as relatively suitable for kinetic energy estimation in the Mediterranean area. The comparison included 11 KE–I relationships expressed with linear, linear-log or exponential formulations. The analyses exposed the rainfall intensity overestimation by the disdrometers and the limited use of the tipping bucket rain gauge for kinetic energy estimation under such climate conditions. According to our results, the established KE–I relationship for 5-min intensity data in Koseze is recommended to be used while estimating rainfall kinetic energy in the Mediterranean part of Slovenia. As input data, rainfall intensities measured with precise weighing rain gauges, as those installed in the Slovenian meteorological network, should be used. However, when using rainfall intensity data obtained with a tipping bucket rain gauge of lower accuracy or insufficient intensity range, the exponential relationship of is expected to deliver better kinetic energy estimations. [Copyright &y& Elsevier]