Using Groundwater for Irrigation in Semi-Arid, Hard-Rock Areas in Peninsular India and the Role of UNESCO-IUGS-IGCP Project GROWNET
Ground Water Institute, India
Most of the groundwater pumped from an aquifer for irrigation of crops is consumed by the crops for their growth and is lost from the liquid phase of the water cycle. Agricultural use is thus mainly consumptive. On the other hand, most of the surface water or groundwater used for industrial or domestic purpose remains as water, albeit of degraded quality, which could be improved by treatment. Reuse and recirculation of the resource is thus possible. In semiarid regions of Peninsular India, the annual rainfall of 350 mm to 500 mm during the monsoon season (June-September), takes place in the form of a few rainstorms. Recently, the climatic pattern is becoming more uncertain and erratic. Degradation of watersheds is causing fast runoff towards major streams and less recharge to groundwater. Surface water sources are meager in most of the watersheds and the hard rock aquifers yield only modest quantities of groundwater. When the sustainability of the groundwater resource is thus threatened, there is naturally a tendency to question the wastage of precious groundwater for irrigation. People often refer to the productivity or the contribution to the GDP of one cubic meter (Cu. M) of groundwater used for irrigation by the farmers and the same quantity used by a rural industry. In other words there is a conflict between the farmers and the industries which have been encouraged by the Government to leave the highly developed urban centers and move to rural areas. But groundwater is the life-line for farmers who wish to dig or drill wells and move away from the perpetual poverty of dry-land farming. Therefore, even amongst the farmers, there is an intense competition for getting more and more share of groundwater. The average size of farm is about 2 hectares per family. Those who are lucky to have a good yielding dug well or bore well in their farm pump as much supply of groundwater as possible and irrigate high value, water-intensive crops like sugarcane and bananas. Others continue their efforts to get more groundwater from several wells within their farm. The down-the-hole hammer type drilling machines have considerably reduced the cost and time for drilling a bore. A 150 mm diameter bore of 100 m depth costs only around $350 to $400 in the U.S. The number of trial bores is therefore increasing every year. The pumpage is increasing; the water table is depleting and so also the yields. Efforts for recharge augmentation are few and scattered. This paper examines the scenario of groundwater use in Peninsular India and suggests governance at village level and active involvement of farmers in recharge augmentation, as the management tools. It also emphasizes the role of UNESCO-IUGS-IGCP Project GROWNET in disseminating the Best Practices in groundwater management. The author is the Project Leader of GROWNET.