8. Analysis of Hydrological Drought in the Eastern Part of Slovakia Using Standardized Precipitation Index

Meteorological drought is a natural phenomenon whose probability and frequency of occurrence increases with increasing the global air temperature. Over the last 138 years, the average annual air temperature in Slovakia has increased between (1.7 and −1.8 °C). This paper presents the analysis of drought in the eastern part of Slovakia using Standardized Precipitation Index (SPI) computed in 12 and 24 months’ time scales for classification of historical drought events for the period (1972–2014). The analysis was done at four precipitation stations localized in sub-catchment Bodrog that situated in the Eastern part of Slovakia. Then, the RUN method was used to identify extreme drought event. SPI value less than (−2) indicates drought condition. A one-dimensional frequency analysis of drought risk was performed in order to determine the probability of its occurrence and evaluating the negative effects of long-term precipitation deficits on surface and groundwater levels, aquatic fauna and flora. The results showed that the year 2003 was a significant year in which extreme meteorological drought was recorded at all precipitation stations. The most vulnerable area with an extreme rainfall deficit is the area in the middle of Bodrog basin, where meteorological droughts can rarely be expected, but can persist for a longer period. This methodology can be applied in different locations of the world as it is considered a broad methodology for drought analysis that based on the availability of data at certain locations.