SURFACE RUNOFF Meaning and
Definition
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Surface runoff is defined as the movement of water across the land surface. It refers to the flow of water that occurs when rainfall, irrigation, or snowmelt exceeds the soil's capacity to absorb it. This excess water then travels above the ground, typically through natural channels such as rivers, streams, or man-made drainage systems like gutters and storm sewers.
Surface runoff plays a crucial role in the water cycle, as it is responsible for transporting water from the land surface to bodies of water such as lakes, rivers, and oceans. It is a major contributor to freshwater supplies, replenishing groundwater and maintaining the overall balance of water distribution within ecosystems.
Factors that influence the rate and volume of surface runoff include the size and slope of the land, soil type and moisture content, vegetation cover, and the intensity and duration of rainfall. Steep slopes and impermeable surfaces like concrete or asphalt can enhance the rate of runoff, as the water has limited opportunities to infiltrate the ground.
Surface runoff can have both positive and negative impacts. On the positive side, it can provide a vital source of water for irrigation and agricultural activities. However, excessive runoff can lead to soil erosion, landslide hazards, and flooding, as it can overwhelm natural drainage systems. It also carries pollutants, such as sediment, chemicals, and fertilizers, from the land into bodies of water, contributing to water pollution and degradation of aquatic ecosystems. Therefore, managing and controlling surface runoff is essential for both water resource management and environmental protection.
Etymology of SURFACE RUNOFF
The word "surface runoff" consists of two components: "surface" and "runoff".
1. Surface: The term "surface" originated from the Latin word "superficies", which means "outer or upper part". It entered Middle English through Old French as "surfas" and eventually evolved into "surface" in the 17th century. The word refers to the top layer or the exterior part of something.
2. Runoff: The word "runoff" indicates the flow or movement of water. Its etymology can be traced back to the Old English word "rinnan", which means "to run". Over time, this term evolved into "runoff" in the 19th century, referring to water running off the surface, typically due to rainfall or melting snow.
