Selecting the Best Location for Constructing a Reservoir for Agricultural Water Supply Using a Combination of Boolean and Fuzzy Logic (Case Study: Qoyijq Watershed)

Providing the required water at different stages of plant growth has always been a major concern for farmers. The irregular spatial and temporal distribution of rainfall creates challenges for farmers in providing the required water for agricultural lands. A significant portion of rainfall occurs during non-agricultural seasons and is lost without storage. Therefore, one of the effective water resource management strategies in northern regions of the country is the construction of Ab-Bandans (traditional water reservoirs). In this study, seven geological criteria, slope, soil depth, sub-basin discharge rate, distance from fault, distance from road, and distance from river were identified and selected according to the characteristics of the region. Then, using Boolean logic, the areas that are unconstrained for constructing water dams were determined. Then, using the fuzzy logic method, unconstrained areas were prioritized to select the best location for reservoir construction. The results of the Boolean method showed that 4.3% of the region is susceptible to constructing water dams. Further analysis of the identified suitable areas using the fuzzy method showed that 0.4% of the area was categorized as relatively suitable, 2% as suitable, and 1.9% as highly suitable for constructing reservoir. Also, using these two logics showed that the southwestern parts of the region are suitable places for reservoir construction.