Definitions for "Direct Runoff"
In hydrologic terms, the runoff entering stream channels promptly after rainfall or snowmelt. Superposed on base runoff, it forms the bulk of the hydrograph of a flood.
Direct runoff is the sum of overland flow and interflow (water flow in the top soil layer). Direct runoff reaches the stream shortly after it falls as rain and is discharged from the basin within one or two days.
The runoff entering stream channels promptly after rainfall or snowmelt. Superposed on base runoff, it forms the bulk of the hydrograph of a flood. The terms base runoff and direct runoff are time classifications of runoff. The terms ground-water runoff and surface runoff are classifications according to source.