Where does the water go when it’s not in the rivers?
Hint: It doesn’t cease to exist, it simply changes location.
If there is a ‘shortage’ of water, how do we have more plant life on earth now than we did a century ago?
The water ends up e.g. in Sahara.
Sahara, or, rather parts of Sahara are Greening due to increased rainfall.
https://www.thegwpf.org/images/stories/gwpf-reports/mueller-sahel.pdf
Ice at the polar caps?