4 ms·

most rivers are circular - just that the upstream water flow is invisible, by virtue of being in water vapor form.

• mirimir 9y ago
  That's very deep. I'm impressed. Sincerely.
  • maxerickson 9y ago
    But is it true? The flow rate of the Mississippi (I got ~500 cubic km/year) is about 0.025 Great Lakes (20,000 cubic km combined) per year. The oceans are 1.37 billion cubic km.
    • mirimir 9y ago
      Yes, it's true. Most of the water that flows from the Mississippi into the Gulf of Mexico comes from rain. And most of that rain comes from ocean evaporation. Sure, there's some input from aquifers, and some recharging of aquifers. And there's evaporation from the Mississippi, its tributaries, and all of the associated lakes, wetlands, and so forth. But the fact remains that the Mississippi is part of the global water cycle. And cycles are circles.
      • maxerickson 9y ago
        I sort of assumed that knowledge of the water cycle was a given. But how fast does the water have to cycle for a named river to be part of a circle? Does once every 10 million years do it?
        • mirimir 9y ago
          That's a fair point :)