To my understanding, a river’s source is fueled by snow and rain, but is it enough to keep it running for that long? Afterall the source doesn’t get rain/snow 24/7 so wouldn’t bigger rivers drain the source in a matter of weeks instead of many hundreds of years?
In: Planetary Science
Most rivers will vary dramatically over the course of years in terms of how much water is flowing in them. Sometimes they might get nearly dry or even completely dry, and at other times they might overflow their banks.
One thing to keep in mind is that the presence of lakes helps to normalize the level of rivers. They typically form where there is a bottle neck holding back much of the potential flow of the river and only allowing a smaller amount out. The rest backs up and forms a reservoir, and when there is not as much rain or snow it will continue to trickle out from that reservoir for a long time.
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