eli5: Why does there continue to be water in a river, even though it doesn’t rain all the time in the upper parts?

Question

eli5: Why does there continue to be water in a river, even though it doesn’t rain all the time in the upper parts?

In: 29

Answer 1

People have mentioned the water in the ground already, so I’d just like to point out that trees are a huge part of this. Trees can store literally tens of thousands of gallons inside them, which they slowly release over time through multiple different processes. This is a huge part of why when you cut down all the trees, flooding becomes much more common and rivers become a lot less healthy. The trees aren’t there to store and purify it anymore.