Determination of Water Losses through the Agricultural Water Conveyance, Distribution, and Delivery System, Case Study of Roodasht Irrigation District, Isfahan

Significant water losses occurred within the Agricultural Water Conveyance, Distribution, and Delivery System in Iranian irrigation districts due to inappropriate operation and maintenance activities. Appropriate agricultural water programming and management need to determine these water losses require costly, time-consuming, and sequential measurement activities. This study proposed a practical approach to find out the approximated values of the losses that occurred in the systems mentioned above. In this respect, the irrigation water requirement of the crops during the cultivated season of 2015-2016 was calculated using the AquaCrop model upon considering applied efficiency in the farm scales. Then, the daily operational water losses were calculated by subtracting the daily gross irrigation water requirement and evaporation losses from the measure daily canal inflow. The obtained results revealed that daily operational water losses vary in a range of 30-60%, which were more significant than the values reported in the Iranian national standard for designing and operation of the irrigation districts (total losses are 10-20%). The reason to justify these water losses is mattered with a lack of operational knowledge, hydraulic basis of the open conveyance and distribution canal networks.