The process of removal of excess surface or ground water from land by means of surface or sub-surface drainage.
Hydraulic Properties of Soil:
The Properties which are involved in water retention and transmission in soil i.e. specific water capacity (c), hydraulic conductivity (k)and soil water diffusivity (d).
Diffusivity of Water (d):
It is the radio of the hydraulic conductivity to the specific water capacity and its also a function of water content expressed in cm2/sec.
Hydraulic Conductivity ( k):
It is the flux of water per unit gradient of hydraulic potential which is demoted as k and expressed in cms/hour.
Dareylaw V= KI
:. K = V/I
Where, V= effective velocity of flow, cm/hr
K= coefficient of permeability cm/hr
I= hydraulic gradient
The hydraulic head drop per unit distance in the direction of flow (dh/dl) is called as the hydraulic gradient.
It is the flux or (rate of movement) of water passing through the soil surface and moving laterally on down ward into the soil.
1 ATM = 76cm.Mercury =1033 cm water
1 Bar= 1000 cm water.
These are deep black soil containing > 30% clay and 0 to 50 cm profile, having swell, shrink property which result in the development of gi/gai micro relief and 1 cm wide crack upto 50 cm soil depth.