Comparison of rainfall characteristics and rainfall erosivity between two experimental sites in Austria and Slovenia

The aim of this study was to compare the rainfall characteristics and rainfall erosivity between two locations in the Danube River Basin, the Hydrological Open Air Laboratory (HOAL) agricultural catchment in Austria and an experimental plot located in an urban park in Ljubljana, Slovenia. The variability of rainfall characteristics and rainfall erosivity were investigated using 5-year-long measurements (2014 – 2018) of rainfall (amount, duration and intensity of rainfall) and drop size distributions (diameter, velocity and median volume diameter of the drops). Despite having the same Köppen-Geiger climate classification, differences were found between the two study sites. The long-term annual average total precipitation was almost twice as much in Ljubljana compared to the HOAL. According to the results of the hierarchical clustering analysis, larger and more intense rainfall events occurred in Ljubljana than in the HOAL, but the average drop characteristics were lower for the events in Ljubljana. Furthermore, if the events were not extreme, their characteristics were similar regardless of location. The rainfall intensities tended to peak in the summer months at both sites, when rainfall durations were shorter, and larger and faster drops were observed. The rainfall erosivity was found to be between 2-5 times greater in each year in Ljubljana than in the HOAL because of the more intense rainfall and single faster and larger drops during events.

 

Acknowledgment: This contribution is part of the ongoing research project entitled “Evaluation of the impact of rainfall interception on soil erosion” supported by the Slovenian Research and Innovation Agency (J2-4489) and the Austrian Science Fund (FWF) I 6254-N.