I am writing a story where a planet has all the rivers going from North to South and the villain is redirecting the rivers so that they go South to North, leading to bad stuff happening. The obvious problem with this planet is that if all rivers meet at the South Pole, then how does the water get back to the rivers' source? The answer is simple. There is a really big tunnel that goes from the South Pole straight to the North Pole. How this formed is not important; Douglas Adams levels of weirdness is
allowed encouraged. This leads to 2 less obvious problems.
The first is that if the water gets to its source without any work being done on it, then this planet is a perpetual motion machine. The second is that as the water falls, its potential energy is being converted into kinetic energy. Kinetic energy is basically temperature, so the water is getting REALLY hot. I do not know what happens to water when it gets hot enough to boil while free falling in a confined space and I will bet money that it is not good.
That I have figured out so far:
Thanks for your help.