Waterfalls are commonly formed in the upper course of the river.At these times the channel is often narrow and deep. When the river courses over resistant bedrock, erosion happens slowly, while downstream the erosion occurs more rapidly. As the watercourse increases its velocity at the edge of the waterfall, it plucks material from the riverbed. Whirlpools created in the turbulence as well as sand and stones carried by the watercourse increase the erosion capacity.This causes the waterfall to carve deeper into the bed and to recede upstream.
Uploaded: Jul 14, 2016