River valley

River valleys

The development of a river valley is affected by the character of the bedrock or alluvium over which the river or stream flows, the elevational difference between its top and bottom, and the climate. Typically the flow will increase downstream and the gradient will decrease. In the upper valley, the stream will most effectively erode its bed through corrasion to produce a steep-sided V-shaped valley. The presence of more resistant rock bands, of geological faults, fractures, and folds may determine the course of the stream and result in a twisting course with interlocking spurs.