When water is lifted from surface sources or underground sources by man or animal power, mechanical or electrical power and directly supplied to the agricultural land, then it is known as Lift Irrigation. In this method, isolated small areas can be irrigated. The vast areas cannot be included in this system. lift irrigation can be divided into two groups.
(a) Lifting of water by man or animal power.
(b) Lifting of water by mechanical or electrical power.
When mechanical or electrical powers are not available in the villages or the economic condition of the farmers is not good enough to afford this expensive method, the lifting of water is done by the following method from the surface sources( like ponds, lakes, rivers, etc):
(3) Persian wheel
(4) swinging busket
(6) Rati or pulley
(7) wind lass
When mechanical or electrical power is available in villages or the farmers can afford the expenditure for the installation of the same, the underground water is lifted by pumps( diesel pump set or electrical pump set) and directly supplied to the agricultural land. The underground water may be available from the following sources:
(1) Open well
(2) Shallow tube well
(3) Deep tube well
Nowadays, the pumping system of lift irrigation from Shallow or deep tube well is widely practised.
Advantages of Lift irrigation
The following are the advantages of lift irrigation
(1)The farmers can supply water to their fields according to the requirement, and hence there is no possibility of over – irrigation.
(2) The water table is lowered when water is lifted from the wells thereby reducing chances of waterlogging in the area.
(3) As water is supplied directly to the fields, there is no water loss due to conveyance.
(4) The initial cost is low as there is no necessity of constructing hydraulic structures.
(5) As the loss of water is low, the duty of water is high.
(6) The maintenance cost is low.
(7) More than one crop can be grown in a year on the same land.
(8) Loss of valuable land is prevented as there is no necessity of constructing the network of canals.
(9)The water of the well is cooler in the hot season and warmer in the cold season.
This phenomenon is favourable for the crops.
Disadvantages of Lift Irrigation
The following are the disadvantages of lift irrigation.
(1) In summer the surface water may be dried up and the water table may go down below the suction head. Hence, the lift irrigation from the surface source and from the shallow tube well May fail in summer.
(2) If the lifting mechanism(i.e. pump) fails due to mechanical or electrical failure, then water cannot be supplied until the mechanism is restored.
(3) The well water has no silt content. The yield of a crop, therefore, depends on chemical fertilizer, which is costly.
(4) The lift irrigation is a consideration with the yield of the crop is not cost-effective.
Book – Irrigation Engineering, Writer – N N Basak