The implementation of the national Delta Programme contributes to the preservation and strengthening of all the functions of the IJsselmeer area, now and in the future. A Delta Decision and preferred strategy have been drawn up for this area.
The IJsselmeer area is at the heart of Dutch water management. It harbours special values for nature and cultural history. The Afsluitdijk barrier dam has provided the entire area with more protection and made land reclamation possible. It also created a freshwater buffer that benefits drinking water supplies, agriculture, industry and nature in much of the Netherlands. Society as a whole uses the lakes and their shores in many ways, for example for leisure activities and shipping.
Sea levels are continuing to rise, possibly faster than previously expected. In recent years, it has become increasingly clear that it will become more difficult to discharge IJsselmeer water into the Wadden Sea if the current lake levels are maintained. At the same time, because of climate change, more river water is flowing into the IJsselmeer when conditions are extremely wet. As a result, flood risk management is under increasing pressure. In longer dry periods, the influx of water may actually decrease. This was also evident in the summer of 2018. The low level of water in the IJssel meant that no water was discharged into the Wadden Sea for a long period of time then, with salinisation as a consequence. It will be necessary to respond using water level management. The expectation is that economic developments, reducing land subsidence and the effects of climate change are also expected to result in increased demand for fresh water.
Generic Delta Decisions
To preserve the functions of the IJsselmeer area in the future as well, it is important to respond flexibly to developments and new insights. The basis for this has been set out in the three generic Delta Decisions of the Delta Programme: Flood risk Management, Fresh water, and Spatial adaptation.
There is also a Delta Decision for the IJsselmeer Area. It specifically addresses water level management in the IJsselmeer and Markermeer lakes in relation to the freshwater supplies and water discharge into the Wadden Sea. The Delta Programme states that the national government will maintain the average winter level in the IJsselmeer and Markermeer in line with the Water Level Decree for the IJsselmeer Area. This Decree also safeguards freshwater supplies by introducing flexible water level management during the summer. Water is discharged from the IJsselmeer to the Wadden Sea with a combination of gravity discharge and pumping at the Afsluitdijk barrier dam.
Preferred strategy for the IJsselmeer area
A preferred strategy for the IJsselmeer area has been drawn up elaborating the details of the Delta Decision. It defines goals and measures for maintaining the standard of flood risk management and freshwater supplies, and for increasing flexibility. Regional visions of the future and planning for investments with a long life cycle are very important here.
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