Discharge capacity of pump based on crop requirements
The pump discharge should meet the peak demand of water for the selected cropping pattern. The rate of pumping depends on the area under different crops, the water requirement of the crops, rotation period (interval between two successive irrigations of a crop) and the duration the pump is operated each day. It may be computed by the following relationship:
Q = rate of discharge of pump (litres/sec)
A = area of land under the crop (hectares)
Y = depth of irrigation (cm)
R = rotation period (days)
T = duration of pumping (hours/day)
Lift Irrigation Systems
In lift irrigation projects, water is lifted directly from rivers or streams or from suitable points at different segments of a canal system. River lift irrigation schemes are feasible in regions where the stream flow is adequate during the peak period of irrigation demand by the crops and where electricity or diesel oil is available at reasonable cost. Canal lift irrigation schemes are beneficial in many areas where sizable land area adjoining a canal, but lying at higher elevations cannot be irrigated through gravity flow from the canal. The water can be pumped to one or more distribution chambers located at suitable points in the command area from where it is distributed through appropriate water distribution systems.
In many tank irrigation projects and small and medium scale reservoir projects, lift irrigation from tanks and reservoirs is sometimes practiced in situations where cultivation in the catchment area adjoining the reservoir may not result in excessive soil erosion and subsequent silting up of tanks/reservoirs.