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Surface runoff is defined as precipitation (rain, snow, sleet, or hail [5]) that reaches a surface stream without ever passing below the soil surface. [6] It is distinct from direct runoff, which is runoff that reaches surface streams immediately after rainfall or melting snowfall and excludes runoff generated by the melting of snowpack or ...
If the precipitation rate exceeds the infiltration rate, runoff will usually occur unless there is some physical barrier. Infiltrometers, parameters and rainfall simulators are all devices that can be used to measure infiltration rates. [2] Infiltration is caused by multiple factors including; gravity, capillary forces, adsorption, and osmosis.
He summarized his conclusions with four laws: the law of stream numbers, the law of stream lengths, the limits of infiltration capacity, and the runoff-detention-storage relation. His results demonstrate that the salient factor in aqueous soil erosion is the minimum length of overland flow necessary to produce enough runoff to affect erosion.
Runoff can also induce bioaccumulation and biomagnification of toxins in ocean life. Small amounts of heavy metals are carried by runoff into the oceans, which can accumulate within aquatic animals to cause metal poisoning. This heavy metal poisoning can also affect humans, since ingesting a poisoned animal increases the risk of heavy metal ...
The speed at which a fluid flows past an object varies with distance from the object's surface. The region surrounding an object where the air speed approaches zero is known as the boundary layer. [3] It is here that surface friction most affects flow; irregularities in surfaces may affect boundary layer thickness, and hence act to disrupt flow ...
Runoff is the flow of water across the earth, and is a major component in the hydrological cycle. Runoff that flows over land before reaching a watercourse is referred to as surface runoff or overland flow. Once in a watercourse, runoff is referred to as streamflow, channel runoff, or river runoff. Urban runoff is surface runoff created by ...
If the soil is saturated, or if the rainfall rate is greater than the rate at which water can infiltrate into the soil, surface runoff occurs. If the runoff has sufficient flow energy, it will transport loosened soil particles down the slope. [10] Sheet erosion is the transport of loosened soil particles by overland flow. [10]
Levels of evapotranspiration in a given area are primarily controlled by three factors: [10] Firstly, the amount of water present. Secondly, the amount of energy present in the air and soil (e.g. heat, measured by the global surface temperature); and thirdly the ability of the atmosphere to take up water .