After the construction of the Afsluitdijk, the IJsselmeer became a region of fresh water, fed by the river IJssel. This large supply of fresh water is a key source of drinking water and water for agriculture. Large parts of the Province of North Holland get their drinking water from the IJsselmeer, and water for agriculture is transported to all the northern provinces via locks and canals.
Due to the growing supply from the IJssel, more and more water ends up in the IJsselmeer. The two discharge sluices in the Afsluitdijk – at Den Oever and Kornwerderzand – ensure that this surplus water is discharged into the Wadden Sea. This is only possible if the water in the IJsselmeer is higher than that in the Wadden Sea. Due to rising sea levels, however, the water level in the Wadden Sea is constantly rising. To be able to remove the water as well if the water in the IJsselmeer is lower than the Wadden Sea, we will be installing pumps in the discharge sluices at Den Oever.