Surface runoff is water, from rain, snowmelt, or other sources, that flows over the land surface, and is a major component of the water cycle.
Runoff that occurs on surfaces before reaching a channel is also called overland flow.
A land area which produces runoff draining to a common point is called a watershed.
When runoff flows along the ground, it can pick up soil contaminants such as petroleum, pesticides, or fertilizers that become discharge or overland flow.
Urbanization increases surface runoff, by creating more impervious surfaces such as pavement and buildings do not allow percolation of the water down through the soil to the aquifer.
It is instead forced directly into streams, where erosion and siltation can be major problems, even when flooding is not.
Increased runoff reduces groundwater recharge, thus lowering the water table and making droughts worse, especially for farmers and others who depend on water wells.
Infiltration (hydrology) Infiltration is the process by which water on the ground surface enters the soil. Infiltration is governed by two forces, gravity, and capillary ... >
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Groundwater Groundwater is water located beneath the ground surface in soil pore spaces and in the fractures of geologic formations. A formation of rock/soil is ... >
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Sewer Sewers transport wastewater from buildings to treatment facilities. Storm sewers (also storm drains) are large pipes that transport storm water ... >
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Erosion Erosion is the displacement of solids (soil, mud, rock and other particles) by the agents of wind, water or ice, by downward or down-slope movement ... >
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Water pollution Water pollution is a large set of adverse effects upon water bodies (lakes, rivers, oceans, groundwater) caused by human activities. Although natural ... >
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Landslide A landslide is a geological phenomenon which includes a wide range of ground movement, such as rock falls, deep failure of slopes, and shallow debris ... >
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Water resources Water resources are sources of water that are useful or potentially useful to humans. It is important because it is needed for life to exist. Many ... >
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Estuary An estuary is a semi-enclosed coastal body of water with one or more rivers or streams flowing into it, and with a free connection to the open sea. ... >
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Slash and burn Slash and burn (a specific practice that may be part of shifting cultivation or swidden-fallow agriculture) is an agricultural procedure widely used ... >
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Eutrophication Eutrophication is the enrichment of an ecosystem with chemical nutrients, typically compounds containing nitrogen, phosphorus, or both. ... >
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