Big river floodplain forests are the richest yet most highly diminished and endangered forest ecosystems. Water engineering projects conducted on rivers and in river valleys, land use changes, and deforestation have contributed to these ecosystems’ degradation. Less than 10% of the natural forest floodplain area in Poland is currently covered by floodplain forests. Uroczysko Warta forest is one of the best preserved and largest natural floodplain forests in Poland, located in the Warta River Valley (the Oder River Basin). Damming of the Warta (Jeziorsko Reservoir) has changed the river regime and flooding patterns downstream (reduced flooding area and decreased flooding frequency), initiating floodplain forest disintegration. In response, a protection project has been undertaken in Uroczysko Warta. The project employs a system of water engineering constructions (flashboard gates, river sills, and culverts with flap check valves). The water engineering system is supposed to improve and reestablish hydrological conditions similar to the natural and stop disintegration processes occurring in floodplain forests. The paper presents technical solutions implemented for protection of Uroczysko Warta floodplain forests, the initial results after implementation of the project and research perspectives aimed at assessment of hydrological restoration effectiveness.