The term for water moving along the ground surface is overland flow or surface runoff. Overland flow occurs when the rate of water input, either from rainfall or melting snow, exceeds the rate of water infiltration into the ground. This results in water accumulating on the land surface and flowing downhill in response to gravity. Overland flow can be a significant source of erosion, as it carries away soil and other sediments. It can also cause flooding and damage to infrastructure, such as roads and buildings.