Investigation of Spatial and Temporal Variability of Hydrological Drought in Slovenia Using the Standardised Streamflow Index (SSI)

Drought is a complex phenomenon with high spatial and temporal variability. Water scarcity has become growing problem in Slovenia recent decades. Therefore, the variability of hydrological drought was investigated this study by analysing Standardized Streamflow Index (SSI). Monthly discharge data series from 46 gauging stations for period 1961–2016 were used to calculate SSI values at five different time scales (1, 3, 6, 12, 24 months). The results indicate that frequency intensity droughts increased decades most analysed all considered. Spring summer periods identified as critical terms water deficit. vary independently location station, confirming regional phenomenon, even small country such Slovenia. However, considerably depending on scale chosen. This also confirmed hierarchical clustering number extreme droughts, various resulted distribution individual groups.