The Crezéepolder is a 75-hectare nature reserve outside the dikes on the Noord river between Hendrik-Ido-Ambacht and Ridderkerk, in the Dutch province of South Holland. The Crezéepolder was formerly used for agriculture after the gorse (sedges) were reclaimed around the Second World War.
Instead of being an agricultural polder, the Crezéepolder will become a nature reserve. The development of this new nature and recreation area involves, among others, Rijkswaterstaat South Holland South, the province of South Holland, the municipalities of Ridderkerk, Hendrik-Ido-Ambacht, and Oasen.[1]
Two openings were made in the dike to allow freshwater from the Noord river to flow in at high tide. The water flows in and out twice a day. The difference between high and low tide here is approximately 90 cm. This is rare in both the Netherlands and Europe. Due to its location on the river, the area is attractive to rare and scarce animals and birds.
Source and more information: Wikipedia