At which point does the greatest stream erosion occur

The greatest stream erosion occurs at the point where the greatest force of the river hits against the side of the bedrock before eroding. Streams on the earth's surface are eroded in three ways: Hydraulic action, abrasion, and solution. Dependent upon the makeup of the soil or surface upon which the force of the river hits, determines the movement of the river's path. 

Answerhave flowing water either episodically or during only a portion of the year;