Water Management and Retention Opportunities Along the Hungarian Section of the Drava River

The water budget of wetland areas and floodplains has been altered due to human intervention and water regulation works. To protect agricultural productivity, ecosystem services, and wetland habitats on the Hungarian side of the Drava River floodplain, this research developed a unified management approach for floodplain rehabilitation through natural water retention. The interaction of a natural water reservoir with the groundwater system was assessed numerically using MODFLOW-NWT. The model was calibrated (correlation coefficient 0.93) with a mean error of 0.04 m and a mean absolute error of 0.05 m. The natural water reservoir for the Korcsina subarea was simulated for +2 m surplus water level and 2 m³ s⁻¹ filling rate (172,800 m³ days⁻¹). The first 1-m water level rise increases the saturation of soil pores, while the second meter works as open excess water, surface water body (intermittent lake). The total upfilling (+2 m relative water level) at the Korcsina subarea requires 33 days and 6,625,675 m³ of water. The discharge (seepage) period lasted 14 days.