| Abstract from DBPedia | Surface runoff (also known as overland flow) is the flow of water occurring on the ground surface when excess rainwater, stormwater, meltwater, or other sources, can no longer sufficiently rapidly infiltrate in the soil. This can occur when the soil is by water to its full capacity, and the rain arrives it. Surface runoff often occurs because impervious areas (such as roofs and pavement) do not allow water to soak into the ground. Furthermore, runoff can occur either through natural or man-made processes. Surface runoff is a major component of the water cycle. It is the primary agent of soil erosion by water. The land area producing runoff that drains to a common point is called a drainage basin. Runoff that occurs on the ground surface before reaching a channel can be a nonpoint source of pollution, as it can carry man-made contaminants or natural forms of pollution (such as rotting leaves). Man-made contaminants in runoff include petroleum, pesticides, fertilizers and others. In addition to causing water erosion and pollution, surface runoff in urban areas is a primary cause of urban flooding, which can result in property damage, damp and mold in basements, and street flooding.表面流出（ひょうめんりゅうしゅつ、英: surface runoff）とは、雨水、雪解け水などから大地を流れる水の流れを表現する用語であり、水循環の主な構成を示す。流路に繋がる表面を流れる流水は、面汚染源とも呼ばれている。流出水が大地を流れるときには、流出水が、石油や農薬（除草剤・殺虫剤）、肥料などの廃水または面汚染源となるような汚染を拾い上げる。 (Source: http://dbpedia.org/resource/Surface_runoff) |
