Some facts about Water erosion :
Water erosion is the detachment and removal of soil material by water. The process may be natural or accelerated by human activity. ... Water erosion wears away the earth's surface. Sheet erosion is the more-or-less uniform removal of soil from the surface.
Water and Wind Erosion (cause)
Water erosion is the removal of soil by water and transportation of the eroded materials away from the point of removal. Water action due to rain erodes the soil and causes activities like gully, rill, and stream erosion leading to the downstream effects of flooding and sedimentation.