Types of measures
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.
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.
Relocating a dike land inwards increases the width of the floodplains and provides more room for the river.
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.
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.
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 or modifying obstacles in the river bed where possible, or modifying them, increases the flow rate of the water in the river.
Dikes are strengthened in areas in which creating more room for the river is not an option.