Economics of Irrigation Groundwater in Vanur and Marakkanam Blocks of Coastal Tamilnadu: Access and Efficiency Analysis

Tamil Nadu is an agricultural state with water constraint and depends upon its available surface and groundwater resources for irrigation. More attention on groundwater irrigation was found in recent years in TamilNadu since more than 95 percent of surface water resources were exhaustively used.Of all the districts, the coastal districts though received high rainfall also found characterized by high groundwater extraction and water scarcity in post – monsoon period. For better insight regarding this,both physical and economic access and efficiency of irrigation ground water were done in this study in selected non – saline coastal blocks vizVanur (semi critical) and Marakkanam (over - exploited) of Villupuramdistrict in TamilNadu through sample farms (90 in each block). The regression analysis revealed that increase in irrigation cost influenced more decrease in magnitude of groundwater access in semi-critical (SC) block and comparatively less decrease in over exploited (OE). The economic access of ground water extracted for increase in water used was found high in OE than SC. Both the physical and economic efficiency of ground water use were found high in SC than OE block. Arriving at the more reduced magnitude of physical and economic ground water access in OE block and raised physical and economic efficiency of water use is essential. This may be possible by less water intensive cropping and other suitable coping strategies.