Flood situation on the rivers Morava and Danube in September 2024 and its impact on the groundwater level

In the second decade of September 2024, after a long-lasting above-average temperature period without widespread precipitation, an extraordinary precipitation event occurred, affecting mainly the west and northwest of Slovakia. Cumulative precipitation amounts ranged from 120 to 250 mm, locally significantly more on the windward sides of the mountains. Extraordinary high precipitation totals were also recorded in surrounding countries, especially in Austria, Czech Republic, Romania and southern Poland. This precipitation event resulted in a flood situation. We observed the highest level of flood activity on all hydro-prognostic profiles of the rivers Morava and Danube. Direct hydraulic interaction between surface water and groundwater in the Záhorská nížina Lowland, Žitný ostrov Island and areas along right bank of the Danube River has caused a significant increase of the groundwater level during the flood wave in these areas. Based on the measured data from the state groundwater monitoring network of the Slovak Hydrometeorological Institute, we assessed the state of the groundwater level in the affected areas during the flood situation. We also identified and analyzed in more detail the areas where groundwater reached the terrain.