Posted on 7 May 2014
The Netherlands lies in a delta, which enables three major rivers: the Rhine, Meuse and Scheldt, to flow out to sea. Without dikes and coastal dunes, around two thirds of the Netherlands would be flooded. Flood protection is therefore a very high priority in water management.
The cadence of Dutch history is marked by floods and the response to them. In 1993 and 1995, the Dutch rivers swelled to unprecedented levels. Large tracts of farmland were inundated; 250,000 people and one million head of livestock were evacuated. As a consequence, the Dutch government took measures to protect the rivers region against flooding.
The implementation of the ‘Room for the River’ approach was born. Started in 2007, it restores the river’s natural flood plain in places where it is least harmful in order to protect those areas that need to be defended.
A total of 19 partners - the provinces, municipalities, water boards and Rijkswaterstaat are cooperating in the implementation of the Room for the River Programme. The Minister of Infrastructure and the Environment bears the overall responsibility for the Programme.
The goal of the Dutch Room for the River Programme is to give the river more room to be able to manage higher water levels. The plan has three objectives:
- By 2015 the branches of the Rhine will cope with a discharge capacity of 16,000 cubic metres of water per second without flooding;
- The measures implemented to increase safety will also improve the overall environmental quality of the river region;
- The extra room the rivers will need in the coming decades to cope with higher discharges due to the forecast climate changes, will remain permanently available.
At more than 30 locations, measures will be taken that give the river space to flood safely. Moreover, the measures will be designed in such a way that they improve the quality of the immediate surroundings. We use nine different solutions to give the rivers more room:
- Lowering of floodplains: Lowering (excavating) an area of the floodplain increases the room for the river at high water levels.
- Deepening summer bed: The river bed is deepened by excavating the surface layer of the river bed. The deepened river bed provides more room for the river.
- Water storage: The Volkerak-Zoommeer lake provides for temporary water storage when exceptional conditions result in the combination of a closed strom surge barrier and high river discharges to the sea.
- Dike relocation: Relocating a dike land inwards increases the width of the floodplains and provides more room for the river.
- Lowering groynes: Groynes stabilise the location of the river and ensure that the river remains at the correct depth. However, at high water levels groynes can form an obstruction to the flow of water in the river. Lowering groynes increases the flow rate of the water in the river.
- High-water channel: A high-water channel is a diked area that branches off from the main river to discharge some of the water via a separate route.
- Depoldering: The dike on the river side of a polder is relocated land inwards. The polder is depoldered and water can flood the area at high water levels.
- Removing obstacles: Removing or modifying obstacles in the river bed where possible, or modifying them, increases the flow rate of the water in the river.
- Strengthening dikes: Dikes are strengthened in areas in which creating more room for the river is not an option.