Rivers and lakes
The Dutch major river basin is internationally renowned for its economic activity along and on the rivers, effective flood protection, sought-after waterfront housing, and successful nature development projects. But according to the Delta Committee, climate change will cause much greater peak river flows in winter, and more frequent droughts during summers. Low river levels in summer will affect commercial shipping and lead to cooling water shortages for factories and power plants. Water shortage and deteriorating water quality will also affect farming, recreation, and natural ecosystems.
To be able to cope with greater peak river flows and water shortages, and to restore our rivers, we need more natural climate buffers:
- along the lower reaches of the Rhine and Maas, buffers can be established by relocating river dikes (to create a wider flood plain), digging peak flow bypasses, and lowering river banks;
- further upstream, buffers can be created by relocating river dikes, developing and restoring overflow areas and reed marshes in the alluvial plain, extracting clay and sand along contour lines, and digging bypasses or even completely new rivers;
- the buffer capacity of the tributary streams of the Maas and IJssel rivers should be restored, and stream mouths should be broadened to slow the outflow into the river.
Natural climate buffers will develop a natural succession of wetlands, marshy grasslands and riparian forests. In addition to better flood protection, this will open up great opportunities for hiking, biking, canoeing and swimming. Rivers passing close to cities will bring cool air during summer, and provide room to relax and enjoy the outdoors. And they are a source of sustainable building materials.
The IJsselmeer area provides wonderful recreation opportunities and beautiful vistas. But it is also a major freshwater reserve for agriculture, drinking water, and ecosystems. The IJsselmeer water level is therefore kept higher in summer than in winter. This reversal of natural water level fluctuation is unfavourable for natural ecosystem development. Moreover, there are no hydrological connections or natural transitions between the IJsselmeer and nearby water systems, such as the Wadden Sea. Because of the rising sea level in the Wadden Sea, the Delta Commission has proposed to raise the IJselmeer water level by another 1,5 m this century, to warrant gravity driven drainage of the IJsselmeer into the Wadden Sea and safeguard the IJsselmeer freshwater reserve.
The IJsselmeer offers great potential for developing additional recreation opportunities and new ecosystems. An all too drastic water level increase would threaten the present IJsselmeer ecosystems and hamper further nature development. Therefore, the provinces surrounding the IJsselmeer should increase their water retention capacities. This way a smaller increase of the IJsselmeer water level will suffice, and a more natural fluctuation pattern (lower water level in summer, higher water level in winter) will be possible.
To turn the IJsselmeer into a true, natural climate buffer, we should also strive for:
- natural shores wherever possible, to improve shore stability;
- water level management that more closely reflects natural fluctuation patterns;
- large-scale nature development, to allow the IJsselmeer to grow along with the rising sea level;
- restoration of the ecological links between the IJsselmeer and nearby water systems;
- more recreation opportunities (canoeing, camping etc);
- restoration of the freshwater-saltwater transition near the Afsluitdijk in combination with planned and necessary dike reinforcement and increased sluice capacity;
- increased habitat availability for birds (the IJsselmeer is an internationally significant bird habitat).