GOOD DECK Flashcards
is the process of water entry into a soil from rainfall, or irrigation.
INFILTRATION
Another word for soil water movement
PERCOLATION
is the process of water flow from one point to another point within the soil.
SOIL WATER MOVEMENT OR PERCOLATION
is the rate at which the water actually infiltrates through the soil during a storm and it must be equal the infiltration capacities or the rainfall rate, which ever is lesser.
INFILTRATION RATE
the maximum rate at which a soil in any given condition is capable of absorbing water
INFILTRATION CAPACITY
is primarily controlled by the rate of soil water movement below the surface and the soil water movement continues after an infiltration event, as the infiltrated water is redistributed.
THE RATE OF INFILTRATION
play a key role in surface runoff, groundwater recharge, evapotranspiration, soil erosion, and transport of chemicals in surface and subsurface waters.
INFILTRATION AND PERCOLATION
Infiltration rate is dependent on a few conditions namely,
Land surface
Land vegetation cover
Surface soil characteristics
Storm characteristics
Surface soil and water temperature,
Chemical properties of the water and soil
Soil properties affecting soil water movement…
Hydraulic conductivity
Water-retention characteristics
a measure of the soil’s ability to transmit water
Hydraulic conductivity
the ability of the soil to store and release water
Water-retention characteristics
is accomplished by analysis of rainfall-runoff data from a watershed.
Areal infiltration estimation
obtained by subtracting runoff volume from rainfall volume.
Infiltration volume
obtained by dividing infiltration volume by rainfall duration.
Average infiltration rate
what is integrated to calculate the total rainfall volume
Rainfall hyetograph
what is integrated to calculate runoff volume
Runoff hydrograph
2 measurements of infiltration
Areal measurement
Point Measurement
are normally made by applying water at a specific site to a finite area and measuring the intake of the soil
Point infiltration measurements
four types of infiltrometers
Ponded-water ring of cylinder type
Sprinkler type
Tension type
Furrow type
infiltrometers should be used to determine infiltration rates for inundated soils such as flood irrigation or pond seepage
Ring
infiltrometers should be used where the effect of rainfall on surface conditions influences the infiltration rate
Sprinkler
used to determine the infiltration rates of soil matrix in the presence of macropores.
Tension infiltrometers
are used when the effect of flowing water is important, as in furrow irrigation.
Furrow infiltrometers
are usually metal rings with a diameter of 30 to 100 cm and a height of 20 cm.
Ring infiltrometers