Waterfalls don't change the rate of flow of water. When 1,000 cfs is flowing into the waterfall, 1,000 cfs is flowing out. Rain events result in rises in flow a

Waterfalls don't change the rate of flow of water. When 1,000 cfs is flowing into the waterfall, 1,000 cfs is flowing out. Rain events result in rises in flow and droughts result in low flows, these are important in a fish's life cycle. Many dams fill up their reservoirs during a rainy season and then slowly release during the dry season. Waterfalls don't do that.