Uncertainty Analysis of Water Distribution Planning in Mian-Ab Irrigation Network in Shooshtar Plain: Application of Genetic Algorithm and Simulated Annealing

Allocated water for agricultural crops in a cropping pattern in different regions and seasons is faced with much variation. Therefore, the cultivation of each crop is subject to climatic conditions, drought tension, precipitation, and crop sensitivity with different levels of uncertainty and risk. In this study, the role of allocated water and its time fluctuations for the main crops in Mian-Ab irrigation network in Shooshtar plain have been investigated. The simulation model of cropping pattern with the objective of maximizing net income with irrigation, investment, cultivation, and land constraints was optimized using a simulated annealing algorithm. The obtained responses in the uncertainty conditions will determine the effect of tension fluctuations in fuzzy analysis process. Fuzzy set theory has been defined with triangular membership function and has been divided into five alpha levels of 0, 0.25, 0.5, 0.75, and 1 to find the fuzzy response of the problem. In each positive or negative α level, a genetic algorithm sub-model has been used with a proximity criterion to find the boundary responses. The results showed that the application of optimal strategy reduced water consumption up to 7 MCM/year and increased the net benefit in cropping pattern more than 5×1010 IRR annually. The developed fuzzy model showed that the water efficiency will be increased at least 30% with a 25% reduction in optimal irrigation..