The large waters of the IJsselmeer region are all designated as Natura 2000 sites and form a crucial core area in the swamp climate corridor. Bordering on the Wadden Sea, the IJsselmeer also has significance for the dune and coast climate corridor. The future water management of the IJsselmeer strongly determines the ecological development possibilities. The current water and nature quality is far below standard.
The IJsselmeer discharges through the drain locks in the Afsluitdijk on the Wadden Sea. With rising sea levels, this becomes more difficult due to the decreasing level difference. In addition to safety, the freshwater supply plays an important role. The IJsselmeer is seen as a collection basin for the water inlet of the north and west of the Netherlands.
As a thinking experiment we want to paint a picture of the IJsselmeer as a dynamic delta water.
By creating (possibly lockable) openings in the Afsluitdijk, the tidal effect can be restored up to Zwolle. The ecological benefits seem considerable: the exchange possibilities for fish are being improved and the intertidal area is being expanded. Depending on the dimensions and the design of the inflow openings, sediment management and water quality can also improve. With this solution, the water level will gradually rise with the sea level.
A condition for the restoration of tidal activity and the fresh-salt gradient in the IJsselmeer is that water withdrawals for agriculture are gradually being phased out. This is at odds with current policy, in which the function of the IJsselmeer as a freshwater basin is leading. But how crucial is that function for the Dutch economy? In any case, research has shown that measures to also supply water to the West of the Netherlands from the IJsselmeer (changes to locks, inlet works and watercourses) are not cost-effective.