If earth were flat, H2O would cover it up to 3000 m deep Fortunately, H2O is concentrated in depressions all over earth surface. Units of Measurement Various units e.g., gallons, acre-feet, etc.
Rainfall is more at the tropics and on windward side of mountains.
In general, the greater the discharge, the better the water supply and more erosion. Erosion and deposition produce tight meanders and eventually oxbow lakes form.