Groundwater Drought Occurrence in Slovakia

Groundwater regime and drought occurrence studies are very important for Slovakia, where groundwater is preferentially used for drinking water supply. It was shown by several studies that the groundwater drought occurs in Slovakia more often since the 1980s, causing problems in various sectors of the Slovak economy. Groundwater drought can be described either through groundwater heads, baseflow, groundwater storage or by the spring yield change. As the main reasons for groundwater drought occurrence, the natural factors and human activities can be mentioned. The amount of groundwater stored in the rock environment primarily depends on the water availability in the area and on the storage capacity of the rock environment itself. The lack of precipitation, high air temperature and the unfavourable storage properties of the rock environment belong to the main natural factors conditioning the groundwater drought occurrence. The groundwater over-abstraction also could increase the sensitivity of the local hydrological system to drought development. The groundwater drought studies for the Slovak territory were first published in the 1990s as a result of drought which hit the territory in the 1982–1984 period. After that, several important scientific works were performed to analyse the factors of drought development, occurrence and impacts on nature and social sphere. Baseflow drought, groundwater head drought and spring yield decrease were studied as presented in the chapter.