Development of a manual operational model to improve the adequacy and dependability of agricultural water distribution in the main irrigation canals

This study investigated the effects of non-structural methods, as practical alternatives for upgrading the operational performance of the irrigation canal. To fulfill this objective, a hydraulic flow simulator model for the Nekoabad irrigation network's main canal was developed, calibrated and then, using two performance evaluation indicators, the adequacy and dependability of water distribution were evaluated. To evaluate water distribution improvement in each one of the non-structural solutions, daily water distribution planning; according to each solution was provided in MATLAB and linked to a simulated mathematical model. To determine the effectiveness of each approach, spatial analysis of changes insecure distribution (sufficient and sustainable) of agricultural water from upstream to downstream of the irrigation network, was done in GIS. The obtained results indicate that the adequacy of surface water distribution was improved 10-11% and 9-7% in the first and second non-structural alternatives, respectively. Besides, the dependability of surface water distribution shows about 13-15% within the application of the alternatives. The results reveal that the second alternatives, fulfilling appropriate water distribution along with the middle and downstream canal reaches, show a more or less good performance.