The Gulches is an area of volcanic rock that is gashed by many channels that lead downhill from the site of a prehistoric glacier to a river  The channels clearly were cut by running water  It was once accepted as fact that the cutting occurred gradually, as the glacier melted  But one geologist theorized that the channels were cut in a short time by an enormous flood  The channels do show physical evidence of having been formed quickly, but the flood theory was originally rejected because scientists knew of no natural process that could melt so much ice so quickly
Paradoxically, today the scientific community accepts the flood theory even though scientists still do not know of a process that can melt so much ice so quickly
The physical effects of water on rock vary with the speed with which those effects are produced.