Surface runoff
Also called: Runoff · Topic: Oceans: Hydrological Cycle, Relief of the Ocean Floor, Temperature and Salinity · NCERT: Class 11, Ch 12 "Water (Oceans)"
Meaning
Surface runoff is the part of rain or snowmelt that flows over the land into streams and rivers. It is the water that does not soak into the ground and does not evaporate. Runoff is high on steep slopes, bare ground, paved surfaces and soil that is already soaked. Too much runoff causes floods and washes away soil. It also means less water refills the groundwater.
Example
In the Himalaya, heavy monsoon rain on steep, bare slopes rushes quickly into rivers. Melting snow adds more water in summer, so streams swell and flash floods can follow.
Don't confuse with
- Infiltration: this is water soaking down into the soil. Runoff is water flowing over the surface.