A condition in which precipitation rate is faster than infiltration rate, and excess water runs over the surface of land.
The topographic movement of a thin film of water from precipitation to lower elevations. With time, this water will begin to organizing its flow into small channels called rills. The rills converge to form progressively larger channels until stream channels are formed. Occurs when the infiltration capacity of an area's soil has been exceeded. Also called sheet flow or runoff.
Surface runoff of water as opposed to channelised runoff following a precipitation event. cf. runoff.