runoff (hydrology)

{{Short description|Flow of water across the earth}}

Runoff is the flow of water across the earth, and is a major component in the hydrological cycle. Runoff that flows over land before reaching a watercourse is referred to as surface runoff or overland flow. Once in a watercourse, runoff is referred to as streamflow, channel runoff, or river runoff.

Urban runoff is surface runoff created by urbanization.