Quantifying Water Use Efficiency in Paddy Production for Different Regions of Thenpennaiyaru River Basin (TRB) of Tamil Nadu

Agriculture is the world's greatest user and consumer of water. Crop irrigation accounts for two-thirds of all world water withdrawals and 85 per cent of total global water consumption. Today we face major issues on water scarcity which is closely related to “water stress” or “water crisis” is the lack of fresh water resources to meet the standard water demand. Irrigated cropping faces some issues on, decreasing water supply owing to increasing extraction and fewer inflows, as well as increased competition from other users in this context the current study focused on the estimation of crop water use efficiency and irrigation efficiency in the different regions of Thenpennaiyaru river basin (TRB) of Tamil Nadu. As per the Central Water Commission’s Basin Report, Thenpennaiyar Basin is the second largest interstate flowing river basin among the 12 basins lying between pennar and Cauvery basins. The river is the main source for irrigating over 38,000 acres in Krishnagiri district; 6250 acres in Dharmapuri district; 17,980 acres in Tiruvannamalai district and 25000 acres in Villupuram district and majority of population depend on this river for agricultural and allied activities. So, this river basin was purposefully selected for the present study to access the efficiency in water usage with the sample size of (320). As per the result CWUE is better in the head region (12.34 quintals/ha/mm) due to consistent water supply, which is directly dependent on effective management practices, which ultimately have higher efficiency and higher yield. Irrigation efficiency is most similarly in all three regions. The CWUE is a better indicator when quantifying the efficiency of a crop production system because it directly reflects the amount of grain yield produced per amount of water used rather than per depth of water applied, which is the case with the IWUE.