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

Many rivers are fed by lakes or snowmelt which will slowly release water over time even if there’s no rain at that particular time. These days, more and more rivers have artificial reservoirs that achieve this by creating a man-made lake with a controlled release volume.