Assessment of Waterlogging Hazard in the Vojvodina Region (Northern Serbia)

In the context of global climate change, waterlogging is a severe agricultural meteorological disaster, causing substantial crop yield losses. It results from heavy rainfall, floods, and phreatic rise, leading to excess water accumulation on the surface or seeping through porous soil. In Vojvodina, waterlogging primarily occurs due to significant precipitation in the non-vegetation period or heavy spring rainfall. This study assessed waterlogging hazard in Vojvodina using soil water balance during the non-vegetation period and maximum daily precipitation in spring (March to May). Data from 1971 to 2021 from eight principal meteorological stations were used. Thiessen polygons defined proximal regions around these stations, assigning meteorological parameters across each polygon. Monthly soil water balance was calculated by considering the difference between precipitation and evapotranspiration, using the FAO-56 Penman-Monteith method and taking into account soil water reserves. Soil water reserves were computed based on solum depth and available water, which varies from 10 mm to 150 mm across the area. Next, time series of soil water balance and maximum daily precipitation in early spring were modeled using the Generalized Extreme Value (GEV) distribution function, a common choice in hydrological analyses. The goodness-of-fit for the GEV distribution was tested using the Anderson-Darling test (significance level 0.05). The GEV distributions were fitted to empirical data using the R package 'fitdistrplus', and critical values for the Anderson-Darling test were calculated via Monte Carlo bootstrap simulations using the 'nsRFA' R package. In the Vojvodina region, drainage systems are generally designed based on the relevant amount of excess water with a return period of 10 years. Therefore, for this study, the amount of excess water in the soil water balance during the non-vegetation period, as well as the maximum daily spring precipitation, both with a ten-year return period, were calculated for all analyzed meteorological stations. The waterlogging hazard map was developed by combining the waterlogging hazard assessments based on the amount of excess water during the non-vegetation period with those based on the maximum daily precipitation in spring. It is estimated that the areas facing the highest waterlogging hazards, which constitute about 30% of Vojvodina's territory, are primarily located in the central, eastern, and southeastern parts of the region. The methodology presented for assessing waterlogging hazard provides a clearer understanding of its spatial distribution, enabling the implementation of measures to improve the planning, management, and maintenance of drainage systems, thereby enhancing prevention and mitigation of its negative impacts. This research was conducted within the the European Union’s Horizon Europe innovation action programme under grant agreement No 101094070, project DALIA (Danube Region Water Lighthouse Action) and COST Actions CA22162 – FutureMed and CA22122 RethinkBlue.