Explanation of flood control in the Netherlands: Rivers are given more room, which decreases the chances of flooding. This policy is called "Room for the Rivers".

Full text:
Rivers: Flood control in The Netherlands

Various measures can be taken to prevent flooding of rivers. Usually, measures follow a strategy of three stages.

First; water is retained in the upper course of the river. The sponge effect of the landscape is used here. You have already seen in the previous video that a landscape can better retain the water if there is a lot of vegetation. This reduces peak discharge, and therefore the risk of flooding. Second, in the middle course, the water is also stored, but in surface water instead of in vegetation and the soil. For example in lakes. This can also limit the peak in the discharge, which reduces the risk of flooding.
Third, In the lower course, the intention is to drain the water to the sea as soon as possible. The less water there is, the less risk of flooding.

In the 1990’s, heavy rainfall caused extremely high water levels in the major rivers in the Netherlands, causing some areas to flood. This led to a new approach. Instead of just strengthening and raising dykes, the rivers are given more room. The measures were thus called “Room for the River”

Many measures of the room for the river program focus on the 3rd stage of the strategy: draining as soon as possible. By lowering the groynes and removing obstacles, the water can be drained faster. A highwater channel can also be built, which means that the water is drained faster.

Some measures focus on the second part of the strategy and ensure that the water can be temporarily stored in surface water, such as in a lake or in the floodplains. The floodplains are the area between the summer and winter dyke.
By digging out the flood plains, the river is thus given more space. As a result, the water level drops downstream, which reduces the risk of flooding there.

Climate Change measures have also been taken into account in the “Room for the River” measures.
Climate change increases the risk of flooding. The temperature rise makes it easier for water from the North Sea to evaporate. Particularly in winter, more precipitation is expected to fall due to climate change. This increases the already high water discharge in winter.
In the summer it will rain less often, but when it starts to rain, there will be much more rainfall per rain shower, so that the peak discharge can also become high. In short: the precipitation regime is also becoming more irregular. This means that the precipitation distribution changes due to climate change.
A final consequence of climate change is that the sea level is rising. As a result, the river is less able to drain the water. The water level in the river rises and flooding can occur.

So by giving the river room, the water level downstream drops, which reduces the risk of flooding.