All the water in the Rhine catchment area follows the water cycle. ‘Cycle’ is the word used to show that things always happen in a certain order. Look at the arrows in the diagram of the water cycle.
You can see that everything is connected, from the Alps to the North Sea.
The small water cycle happens above the sea. Sea water evaporates as it is heated by the sun. The vapour rises and becomes a cloud in the air. The higher it rises, the colder it gets. When it reaches a great height, the water vapour changes to droplets which fall as rain. The water returns to the sea and can then evaporate again. And so on.
Water evaporates everywhere, not just above the sea. This produces clouds everywhere, which move further inland. Clouds have to rise when they meet mountains. The air is much colder there, and the water can no longer hold together. It falls as rain or snow.
The water reaches the land, and ends up in the sea again via streams, rivers, lakes or groundwater.
Snow also melts and returns to the sea. This is called the large water cycle.