- Waterfalls are created when water flows down a rock. The water wears some of the rock away, so the waterfall is steeper. After years of continuous eroison ; the water then falls off the cliff into a plunge pool. Some of the rock that overhangs will eventually fall off into the plunge pool, this will happen more and more. The waterfall will then 'travel' down steam and can force many downstream villages to find somewhere else to live.