Water School

What is runoff?


Runoff is the portion of precipitation that doesn’t soak into soil and instead moves from land to streams or other surface water. Runoff can be caused by precipitation, snowmelt and irrigation that the Earth does not soak up. 

There are three types of runoffs. They include:
•    Surface Runoff: Water after precipitation merges with streams or surface water
•    Subsurface Runoff: Water soaks into the soil and merges into the water table, then flows into the stream
•    Base Runoff: Precipitation soaks into soil and moves into any drain, stream or river; referred to as inter-flow

There are a variety of environmental impacts that runoff can cause. Runoff can carry pollutants from the land to surface and groundwater. A big source of pollution are excess fertilizer and pesticides that runoff from agricultural and residential areas. The chemicals in this runoff can be toxic to humans as well as the wildlife that rely on the surface and groundwater.

Water pollution is not the only risk presented by runoff; it can damage property too. Flooding and erosion are major concerns for property owners, but runoff can be prevented with drainage systems, ground covers and mulch. 

Return to Water School to learn more about water!

Environmental impacts of agricultural runoff
How To Prevent Erosion And Runoff In The Yard?
Understanding the Impacts of Runoff | Shore Stewards | Washington State University




The information provided on this site is intended as background on water within the Brazos River basin. There should be no expectation that this information is all encompassing, complete or in any way examines every aspect of this very complex natural resource.

If you have questions about a post or would like additional information, please contact us or call 888-922-6272.

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