Irrigation is the controlled application of water to croplands.  Its primary objective is to create an optimal soil moisture regime for maximizing crop production and quality while at the same time minimizing the environmental degradation inherent in irrigation of agricultural lands. OR Irrigation is the application of water to the soil to supplement natural precipitation and provide an environment that is optimum for crop production. Well Irrigated crops produce more food.  Irrigation engineering is a kind of civil engineering which includes the study of controlling and harnessing the various natural sources of water.

Irrigation is defined as the process of artificial supply of water to soil for raising crops. It is a science of planning and designing an efficient, low-cost, economic irrigation system tailored to fit natural conditions. It is the engineering of controlling and harnessing the various natural sources of water, by constructing dams and reservoirs, canals and headworks, and finally distributing the water to the agricultural fields. Irrigation engineering includes the study and design of works in connection with river control, drainage of waterlogged areas and generation of hydroelectric power.