A multi-scenario multi-model analysis of regional climate projections in a Central–Eastern European agricultural region: assessing shallow groundwater table responses using an aggregated vertical hydrological model

Abstract The 2022 drought highlighted Hungary's vulnerability to climate change, especially the Great Hungarian Plain. Soil moisture, which is crucial for agriculture, depends on the position of the shallow groundwater table. This study investigated the effects of climate change on groundwater table fluctuations in more than 500 wells on the plain. An integrated vertical hydrological model, assuming negligible horizontal subsurface flows, employed the Dunay–Varga-Haszonits methodology for evaporation and Kovács approach for the water retention curve. Verified with two meteorological databases, the model was accepted for 463 wells based on NSE > 0.4 and RMSE < 0.5 m criteria. The FORESEE HUN v1.0 dataset proved suitable after spatial consistency tests. Examining 28 bias- and discontinuity-corrected climate model projections on these wells revealed a general decline in the groundwater table. Differences between trends to 2050 and 2100 suggested lower groundwater levels by mid-century. This research highlights climate change impacts in a crucial Central-European agricultural region in the Carpathian Basin and emphasizes the importance of modeling climate change-induced changes in shallow groundwater levels in water resources management.