A fuzzy interval dynamic optimization model development for surface water resources allocation based on ecological and water scarcity factors, the case of Simineh River Basin

Allocation of surface water resources is considered as a solution to deal with water stress, especially in low rainfall areas, but the existence of high uncertainty as well as the lack of water. This allocation has always caused problems and this issue has become one of the main problems of governance in low rainfall areas of the world. Hence, in this research, a fuzzy interval probabilistic planning model was designed for the allocation of surface water resources by considering ecological factors and water scarcity. In so doing, after analyzing and validating the model, parametric sensitivity analysis was performed on the ecological and economic factors in the Simineh River, which is one of the important rivers of the Urmia Lake catchment. The results showed that an increase of 10 to 50 percent of water shortage led to a drop in the values ​​of the objective functions. Also, a 50% increase in the pollution production rate has led to a decrease in all economic and ecological goals from 2.5 to 3.5%, and a 50% increase in the removal of pollutants has also led to a 2-3% improvement in economic goals. In conclusion, it can be argued that the water scarcity is one of the consequences of the pollution of this crucial resource, and for this reason, a significant part of water resources are left out of the allocation cycle. With a 100% increase in uncertainty, the ecological goal has dropped by 2.7% and other goals have changed in the range of 1.5% to 2.0%. Considering the variables of water scarcity and water pollution can also affect the output of the developed model and provide more reliable answers, therefore, it is recommended to consider these two factors in future studies.