Flooding is possible at high water levels. One of the reasons for this is that the countryside around the Rhine is increasingly being used by people. Building houses, factories and offices leaves less and less space for the river. The water gets higher. Take a wide dish and pour some water into it. Pour that water into a narrow glass. The water level in the glass will be higher.
Water cannot flow away in a glass, but in a river it can. If the river has less space to flow, the water has to be carried along more quickly. The river flows faster. But think about what happens when you pinch a garden hose. The water has to pass through a smaller opening, and the stream becomes stronger. The water in the Rhine is now flowing more than twice as fast as in the past!
Briefly, because we give the rive less space, the water is flowing fast and water levels are rising.
Landscape that has been shaped by people is called a cultivated landscape. Over the years, the catchment area has become more of a cultivated landscape.
The area around the Rhine is used for farming, and there are houses and factories along the river. Dikes have been built at many points to protect these areas against the water. Dikes are also part of a cultivated landscape.
A landscape that is entirely shaped by nature is called a natural landscape. For example, woods and lakes. The catchment area used to contain more natural landscape. At that time, a lot of extra water could remain behind in the area around the Rhine. And it didn’t matter if they flooded occasionally!