The Hedwige-Prosperpolder is located on the border between Belgium and the Netherlands, along the Scheldt estuary. The Hedwige-Prosperpolder has an area of approximately 465 ha. The area was depoldered beginning of 2023 by excavation of the former primary dyke and an onset of a creek and gully system was excavated in the area itself.<br>In this study an assessment was made on the impact of the depoldered area on the tidal propagation in the Scheldt estuary itself and a comparison with previous model excercises. A data analysis was performed, based on the measured tidal data from gauges along the Western Scheldt and the lower Seascheldt.<br>Based on this analysis, the effect on the highwater levels at Antwerp is estimated at a reduction of about 1 - 2 cm at neap tide and 3 - 5 cm at spring tide. The largest effects are found at Liefkenshoek, just upstream Hedwige-Prosperpolder, the smallest effects at Prosperpolder, just downstream of the depoldered area.