Ranking of suitable areas to underground dam construction(Case Study: Baghak Serney basin, Hormozgan Province)

Despite the low rainfall, which is amplified by disordered time distribution, a large amount of rainfall in Hormozgan province is wasted as runoff due to highly intensive and shower rains. On the other hand, an important part of the reserves of surface water resources such as rivers and dam lakes are losing due to high evaporation potential. Determining susceptible areas for construction of underground storages in plains covered by quaternary deposits is a good way to develop water resources in these conditions. Determination of the proper areas for this purpose depends on various ecological and anthropogenic criteria. Based on the research literature, socio-economic factors (water need and access), underground dam axis (depth, length and lithology), underground dam reservoir (permeability, slope and surface of the reservoir) and water (quantity and quality of water) named as the most important effective criteria. In this research, the Analytic Hierarchy Process (AHP) used to weigh the main and sub-criteria affecting the determination of the potential of underground dam construction in the study area. Sub-criteria of water quantity with a weight of 0.833, water demand with a weight of 0.8 and axis depth and reservoir permeability with a weight of 0.637 are the most important indicators of the research. The information layers of each criterion were fuzzy. Then, using satellite data and field control 14 axes (options) were distinguished and selected. Then by compilation of information layers in the ArcGIS environment, indices were calculated and ranked for each axis. The results showed that options 14 in the northwest of the region has requirements and the capability to build an underground dam. The system sensitivity in the rankings was tested by changing the ±5 and ±10 percent in weight of the highest-grade criteria. The selected option has suitable permeability and the depth of its axis is 9-12 meters. In addition, it is located in sub-basin B1 with an average annual rainfall of 207.1 mm and a rainfall volume of 1.9 million cubic meters. These features are among the suitable potentials for the construction of an underground dam in the region. So the results showed that the model has the sufficient stability in the axes prioritization relative to each other.