infiltrationis the movement of water into the soil surface

7/25/2019 Infiltrationis the Movement of Water INTO the Soil Surface

1/12

Infltrationis the process by which water on the ground surface enters

the soil. Infltration ratein soil scienceis a measure of the rate at which soil

is able to absorb rainfallor irrigation. It is measured in inches per hour or

millimeters per hour. The rate decreases as the soil becomes saturated. If theprecipitation rate exceeds the inltration rate, runowill usually occur unless

there is some physical barrier. It is related to the saturated hydraulic

conductivityof the near-surface soil. The rate of inltration can be measured

using an inltrometer.

Hydraulic conductivity, symbolically represented as , is a property

of vascular plants, soils and rocks, that describes the ease with which a uid
https://en.wikipedia.org/wiki/Soilhttps://en.wikipedia.org/wiki/Soil_sciencehttps://en.wikipedia.org/wiki/Rainfallhttps://en.wikipedia.org/wiki/Irrigationhttps://en.wikipedia.org/wiki/Surface_runoffhttps://en.wikipedia.org/wiki/Hydraulic_conductivityhttps://en.wikipedia.org/wiki/Hydraulic_conductivityhttps://en.wikipedia.org/wiki/Infiltrometerhttps://en.wikipedia.org/wiki/Vascular_plantshttps://en.wikipedia.org/wiki/Soil_sciencehttps://en.wikipedia.org/wiki/Rainfallhttps://en.wikipedia.org/wiki/Irrigationhttps://en.wikipedia.org/wiki/Surface_runoffhttps://en.wikipedia.org/wiki/Hydraulic_conductivityhttps://en.wikipedia.org/wiki/Hydraulic_conductivityhttps://en.wikipedia.org/wiki/Infiltrometerhttps://en.wikipedia.org/wiki/Vascular_plantshttps://en.wikipedia.org/wiki/Soil


2/12

!usually water" can move through pore spaces or fractures. It depends on

the intrinsic permeabilityof the material, the degree of saturation, and on

the densityand viscosityof the uid. #aturated hydraulic conductivity, Ksat,

describes water movement through saturated media.

Infltrometeris a device used to measure the rate of water

inltrationinto soilor other porous media. $ommonly used inltrometers are

single ring or double ring inltrometer, and also disc permeameter.
https://en.wikipedia.org/wiki/Intrinsic_permeabilityhttps://en.wikipedia.org/wiki/Saturation_(chemistry)https://en.wikipedia.org/wiki/Densityhttps://en.wikipedia.org/wiki/Viscosityhttps://en.wikipedia.org/wiki/Infiltration_(hydrology)https://en.wikipedia.org/wiki/Infiltration_(hydrology)https://en.wikipedia.org/wiki/Soilhttps://en.wikipedia.org/wiki/Disc_permeameterhttps://en.wikipedia.org/wiki/Intrinsic_permeabilityhttps://en.wikipedia.org/wiki/Saturation_(chemistry)https://en.wikipedia.org/wiki/Densityhttps://en.wikipedia.org/wiki/Viscosityhttps://en.wikipedia.org/wiki/Infiltration_(hydrology)https://en.wikipedia.org/wiki/Infiltration_(hydrology)https://en.wikipedia.org/wiki/Soilhttps://en.wikipedia.org/wiki/Disc_permeameter


3/12

The single ring involves driving a ring into the soil and supplying

water in the ring either at constant heador alling head condition.

Constant head reers to condition where the amount o water in the

ring is always held constant. Because infltration capacity is themaximum infltration rate, and i infltration rate exceeds the

infltration capacity, runo will e the conse!uence, thereore

maintaining constant head means the rate o water supplied
https://en.wikipedia.org/wiki/Hydraulic_headhttps://en.wikipedia.org/wiki/Hydraulic_head


4/12

corresponds to the infltration capacity.

Infltration is the movement of water I%T& the soil surfaceInltration


5/12

'ercolation ratecontrols the inltration rate

"ercolationis the movement of water (IT)I% the soil matrix.


6/12

'ercolationin soilsis primarily due to gravity pulling the water verticallydownward

The rateof percolation is controlled by grain si*e


7/12

http+www.geol.edurmitch/0soils0percolation.pdf

Infltration and "ercolationInltration and percolation are two related but dierent processes describingthe movement of moisturethrough soil. Inltration is dened as the downward entry of water into thesoil or rock surface !###1,2345" and percolation is the ow of water through soil and porous orfractured rock. In hydrologic

modeling, these two processes are usually modeled separately. Inltrationrate is the rate at which a soilunder specied conditions absorbs falling rain, melting snow, or surfacewater expressed in depth ofwater per unit time !1#$6, 23/5". 'ercolation rate, although more di7cult tomeasure directly,represents the rate at which soil moisture moves down through the soil orpermeable rock.Inltration rate usually demonstrates a rather rapid decline with time fromthe beginning of inltrationand reaches a steady state as the soil eventually becomes saturated. 1t this

stage, the inltration ratewould be approximately e8ual to the percolation rate, which in general ismuch lower than the initialsurface inltration rate. Therefore, in practice the steady state inltrationrate can be considered as agood representation of the percolation rate when soil texture andcharacteristics are similar between
http://www.geol.edu/rjmitch/L8_soils_percolation.pdfhttp://www.geol.edu/rjmitch/L8_soils_percolation.pdf


8/12

upper layers of soil where the inltration rate is measured and lower layerswhere percolation occurs. Ifthe underlain soil layers are dierent from upper soil layers, the steady stateinltration rate may varysignicantly from the percolation rate. The percolation rate in a karst terrain

usually has high spatialvariability both hori*ontally and vertically9 therefore, the steady stateinltration rate is often unable toaccurately represent the rate of percolation in such terrain.

#stimation o the "ercolation $ateThe inltration rate can be estimated from eld tests. The :ouble ;ingInltrometer test is the mostcommonly used method. &ther eld testing methods approved byresponsible


9/12

Impact o "ercolation(hile inltration is important in estimating ood peaks and volumes for all

watersheds, percolation hassignicant impact on watersheds with very sandy soil or karst terrains.

%imulate Infltration and "ercolation &osses in Hydrologic'odelingInltration and percolation are components of hydrologic cycle and areaected by other components.lossary of #oil #cience Terms

#ntry o (ater into %oilInfltration+ Inltration refers to the downward entry or movement of waterintothe soil surface

It is a surface characteristic and hence primarily influenced by thecondition


10/12

of the surface soil.#oil surface with vegetative cover has more infiltration rate than bare soil(arm soils absorb more water than colder ones$oarse surface texture, granular structure and high organic matter

content in

surface soil, all help to increase inltrationInfiltration rate is comparatively lower in wet soils than dry soils)actors aecting infltrationi. $lay mineralsii. #oil Textureiii. #oil structureiv. =oisture contentv. Aegetative covervi. Topography"ercolation+The movement of water through a column of soil is calledpercolation. It is important for two reasons.

i" This is the only source of recharge of ground water which can be usedthroughwells for irrigationii" 'ercolating waters carry plant nutrients down and often out of reach ofplantroots !leaching"

In dry region it is negligible and under high rainfall it is high#andy soils have greater percolation than clayey soilAegetation and high water table reduce the percolation loss

"ermeaility+ It indicates the relative ease of movement of water with in

the soil.The characteristics that determine how fast air and water move through thesoil isknown as permeability. The term hydraulic conductivity is also used whichrefersto the readiness with which a soil transmits uids through ithttp+agridr.intnau61grieagri5@##1$2B2lec2B.pdf

Inltration

Inltration rate ;ate at which water enters the soil at the surface !inhr or cmhr"

$umulative inltration 1ccumulated depth of water inltrating during given time period
http://agridr.in/tnauEAgri/eagri50/SSAC121/lec12.pdfhttp://agridr.in/tnauEAgri/eagri50/SSAC121/lec12.pdf


11/12

Inltrometers

#ingle ;ing :ouble ;ing

http+en.wikipedia.orgwikiInltrometer

Inltration =ethods

)orton and 'hillips Inltration models developed as approximate solutions of an

exact theory !;ichardCs 68uation" >reen D 1mpt

Inltration model developed from an approximate theory to anexact solution

Inltration

;ainwater that soaks into the ground and may reach the groundwater table.
http://en.wikipedia.org/wiki/Infiltrometerhttp://en.wikipedia.org/wiki/Infiltrometer


12/12

>eneral 'rocess of water penetrating from ground into soil

infiltrationis the movement of water into the soil surface

Documents