Methodologies for Tank Irrigation Performance and Management

Tank irrigation in three different typologies in three districts of Tamil Nadu state was compared. Increasing the water supply by 10 ha-cm in Tank only situation will increase the labour employment by 4.3 man-days compared to 11.6 man-days in Tank with wells situation and 15.2 man-days in Wells only situation in a hectare of land. Analysis of farmer participation indicated that by contributing one rupee in tank management would increase the rice yield by 2.4 kg per ha in Tank only situation and 4.6 kg per ha in Tank with wells situation. By increasing one additional well farmers’ contribution for water management would be reduced by Rs.45 per ha and by increasing one supplemental irrigation rice yield can be increased by 243 kg per ha. It needs 355 additional wells for the sample tanks in Tank with wells situation to be with optimal level of groundwater use. The sample tanks in Tank only situation need 190 additional wells to be changed into Tank with wells situation and 417 additional wells to be converted as percolation ponds. The stabilization value of Rs.2 91123 justifies the need for additional investment in wells for supplementary irrigation in the tank command area.