IRRIGATION DEVELOPMENT AND ITS ENVIRONMENTAL CONSEQUENCES IN ARID REGIONS OF INDIA

The present paper examines the nature and dimensions of environmental transformation induced by canal irrigation in the arid region of India . The case study pertains to the Indira Gandhi Canal comand area in Ra jasthan where the density and area of vegetation cover have increased due to afforestation, and the cultivated area has expanded due to irri gation. Consequently, there has been a perceptible improvement in the structure and fertility of sandy soils, but it would require a hercule an effort on the part of the canal authority and local people to reduc e soil erosion and siltation in the lower parts of stage I and the ent ire command area of stage II. Moreover, the water table has been risin g rapidly throughout the command area of stage I. About half of the co mmand area and adjoining Ghaggar basin in Ganganagar District will be facing the danger oi waterlogging by the turn of the century. The inci dence of irrigation-induced alkalization is higher in the lower parts of stage I. Soil alkalinity has appeared within live years of the intr oduction of irrigation in the interdunal basins and is manifested as a strong salt regime or calcareous pans near surface. This calls for im mediate reclamation of the affected area and prevention of its expansi on by altering the strategy of irrigation development, by changing cro pping patterns, and by providing soil drainage.