Simulation and Temporal Spatial Assessment of Surface Water Distribution to Agricultural Units in Abshar Plain, Esfahan

In this study, an assessment of the performance of the surface water distribution system in the Abshar Isfahan irrigation network was conducted. For this purpose, the two main right and left channels and ten secondary channels of this network were integrated into an integral delay simulator model developed in MATLAB. The simulation of surface water distribution between the intakes located in the main and secondary channels for an irrigation season, corresponding to the water year 1400 1401 and divided into five dominant operational scenarios, was carried out. The evaluation of surface water distribution performance involves the use of performance assessment indices, specifically the adequacy of water distribution, for each intake, region, and the entire channel. Additionally, the simulated data was imported into GIS software to analyze the spatial distribution of surface water distribution across the entire network, and maps of the average adequacy index dispersion for each operational scenario were extracted and analyzed. The simulation results indicated a predominantly decreasing trend in water delivery adequacy indices from the upstream intakes to the downstream in both the main and secondary channels. The average surface water distribution adequacy index ranged from 98% to 100%, 90% to 100%, 97% to 84%, 96% to 81%, and 93% to 69% in the upstream intakes and from 80% to 85%, 65% to 70%, 41% to 45%, 30% to 34%, and 20% to 28% in the downstream intakes, in scenarios one through five, namely, from high water availability to severe water scarcity. The results obtained highlighted deficiencies in the existing irrigation system's water distribution adequacy, especially in scenarios of low water availability, along the main and secondary channels. Furthermore, the spatial classification maps revealed a distinct pattern of inefficiency in surface water distribution at the network level and identified vulnerable areas within the network.