My world - think 13th century medieval Europe - has a gigantic waterfall. Imagine Niagara Falls but even bigger, consuming multiple sides of a big mountain. People don't climb the mountain, as it is too steep or the waterfalls make it impossible. One day, the water stops pouring down. The world is shocked and sends a unit to find out what happened. No more water means they can now climb the mountain, which they do.
Now, I want the waterfall to be stopped by unknown people living on the mountain, but we're talking about a massive load of water. My current thoughts are: all the water up the mountains streams through a big cave/tunnel while flowing down, which now is blocked with rocks.
My questions are...
- How big should this tunnel be, to realistically process enough water to keep a waterfall of my magnitude going?
- How would these people block the tunnel, as we probably need gigantic rocks, and explosions aren't possible?
- Does everything I say make sense?
Thank you all so far for your awesome replies. Very interesting. To put some things together:
Where does the water come from? Rain is an option, but as @HDE226868 puts it, this asks for a gigantic surface. Probably too big. Question: can't the mountain be very high with permanent melting snow on top, which creates the flow? Does my mountain still has to be the same size, @RobWatts?
How big can the mountain and tunnel be? @ArtOfCode's calculations say 9m diameter for the tunnel, which is possible to block. Great! @DoubleDouble points out the lake has to be as width as the waterfall. Good point
What blocks the tunnel? Rerouting is a great idea by Mikey, but creates question (posted multiple times): where does the water go to. @youstay-igo suggests to stop multiple small rivers, but I think this will be hard to do simultaneously. Putting a plug in the tunnel that can sustain the pressure can work, combined with rerouting.
Where does the water now go? Would it be possible to be rerouted into the mountain, in a cave system? Of course it will be huge. It streams under the surface & finds a way to the sea. Other options without creating a new waterfall seem impossible, no?