The Nile is 2nd longest, for what it's worth, behind only the Amazon. And, to understate matters a little bit, it's in quite an arid region, so that its waters were quite literally the lifeblood of all Egyptian civilizations.
The Yellow River -- which, for its part, is quite literally the cradle of Chinese civilization -- is in a very similar position. It's the 6th largest river by length, but 113th by flow rate.
Perhaps, as others have just speculated, flow rate was once a lot higher, and now water is being diverted to agricultural and other projects, so that a much smaller fraction of it reaches the sea.
The Yellow River -- which, for its part, is quite literally the cradle of Chinese civilization -- is in a very similar position. It's the 6th largest river by length, but 113th by flow rate.
Perhaps, as others have just speculated, flow rate was once a lot higher, and now water is being diverted to agricultural and other projects, so that a much smaller fraction of it reaches the sea.