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Encyclopedia > 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 action. While smaller pores offer greater resistance to gravity, very small pores pull water through capillary action in addition to and even against the force of gravity. SOiL is a five-piece aggressive rock/Nu Metal band from Chicago, formed in 1997 by ex-members of renowned death metal acts Broken Hope and Oppressor. ... Gravity is a force of attraction that acts between bodies that have mass. ... This article or section does not cite its references or sources. ...

Infiltration rate in soil science is a measure of the rate at which a particular soil is able to absorb rainfall or irrigation. It is measured in inches per hour or millimeters per hour. The rate decreases as the soil becomes saturated. If the precipitation rate exceeds the infiltration rate, runoff will usually occur unless there is some physical barrier. It is related to the saturated hydraulic conductivity of the near-surface soil. Soil science deals with soil as a natural resource on the surface of the earth including soil formation, classification and mapping; physical, chemical, biological, and fertility properties of soils per se; and these properties in relation to the use and management of soils. ... In meteorology, precipitation is any kind of water that falls from the sky as part of the weather. ... High-altitude aerial view of irrigation in the Heart of the Sahara (, ) Irrigation (in agriculture) is the replacement or supplementation of rainfall with water from another source in order to grow crops. ... written by AmerHydraulic conductivity, mathematically represented as , is a property of soil or rock, in the vadose zone or groundwater, that describes the ease with which water can move through pore spaces or fractures. ...

The rate of infiltration is affected by soil characteristics including ease of entry, storage capacity, and transmission rate through the soil. The soil texture and structure, vegetation types and cover, water content of the soil, soil temperature, and rainfall intensity all play a role in dictating infiltration rate and capacity. For example, coarse-grained sandy soils have large spaces between each grain and allow water to infiltrate quickly. Vegetation creates more porous soils by both protecting the soil from pounding rainfall, which can close natural gaps between soil particles, and loosening soil through root action. This is why forested areas have the highest infiltration rates of any vegetative types. Soil texture triangle, showing the 12 major textural classes, and particle size scales. ... In meteorology, precipitation is any kind of water that falls from the sky as part of the weather. ...

The top layer of leaf litter that is not decomposed protects the soil from the pounding action of rain, without this the soil can become far less permeable. In chapparal vegetated areas, the hydrophobic soils in the succulent leaves can be spread over the soil surface with fire, creating large areas of hydrophobic soils. Other conditions that can lower infiltion rates or block them include dry litter that resists re-wetting, or frosts can lower infiltration. If soil is saturated at the time of an intense freezing period, the soil can become a concrete frost on which infiltration rates would be around zero. But any of these infiltration reducing conditions would not be over an entire watershed, there are most likely gaps in the concrete frost or hydrophobic soil where water can infiltrate. Hydrophobic soil - soil that is hydrophobic - causes water to collect on the soil surface rather than infiltrate into the ground. ...

Horton (1933) suggested that infiltration capacity rapidly declines during the early part of a storm and then tends towards an approximately constant value after a couple of hours for the remainder of the event. Previously infiltrated water fills the available storage spaces and reduces the capillary forces drawing water into the pores. Clay particles in the soil may swell as they become wet and thereby reduce the size of the pores. In areas where the ground is not protected by a layer of forest litter, raindrops can detach soil particles from the surface and wash fine particles into surface pores where they can impede the infiltration process.

Once water has infiltrated the soil it remains in the soil, percolates down to the ground water table, or becomes part of the subsurface runoff process.

The process of infiltration can continue only if there is room available for additional water at the soil surface. The available volume for additional water in the soil depends on the porosity of the soil and the rate at which previously infiltrated water can move away from the surface through the soil. The maximum rate that water can enter a soil in a given condition is the infiltration capacity. If the arrival of the water at the soil surface is less than the infiltration capacity, all of the water will infiltrate. If rainfall intensity at the soil surface occurs at a rate that exceeds the infiltration capacity, ponding begins and is followed by runoff over the ground surface, once depression storage is filled. This runoff is called Horton overland flow. The entire hydrologic system of a watershed is sometimes analyed using hydrology transport models, mathematical models that consider infiltration, runoff and channel flow to predict river flow rates and stream water quality. Runoff flowing into a stormwater drain 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[1][2]. Runoff that occurs on surfaces before reaching a channel is also called overland flow. ... Robert Elmer Horton (May 18, 1875 - April 22, 1945) was an American ecologist and soil scientist, considered by many to be the father of modern hydrology. ... River in Madagascar relatively free of sediment load An hydrological transport model is a mathematical model used to simulate river or stream flow and calculate water quality parameters. ... A mathematical model is an abstract model that uses mathematical language to describe the behaviour of a system. ... Water pollution Water pollution is a large set of adverse effects upon water bodies (lakes, rivers, oceans, groundwater) caused by human activities. ...

See also

  Results from FactBites:
ScienceDaily: Sustainability Articles (510 words)
Infiltration is the process by which water on the ground surface enters the soil.
Infiltration is governed by two forces, gravity, and capillary action.
Forestry is the art, science, and practice of studying and managing forests and plantations, and related natural resources.
  More results at FactBites »



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