A waterfall is a place where a stream or river has water flowing from high to low, with a large angle of inclination, rapid water speed, which can create water waves and whirlpools.
Russell Falls, Mount Field National Park, Australia.
Classification of waterfalls:
The reason there is a waterfall is because the river runs through it, encountering a hard rock block that has not been eroded. Along with the soft rock being eroded away, creating low and high steps, also known as river hierarchy .
Besides, during the tectonic process, geological activities create faults, pushing the upper part of the river up, the lower part of the waterfall down. These two causes created the waterfall.
Not only on the ground there are waterfalls, but also underground, there are waterfalls. Underground water sources will create underground rivers, when meeting places where the terrain is high suddenly suddenly low, underground waterfalls will also be formed. The water of the waterfall is the water of the river running through that terrain.