Locating Suitable Sites for Building underground Dam using AHP Multi-criteria Decision Making Method

Use of underground dams can be beneficial for optimal expansion and utilization of water and also for underground water storage. Considering the prevailing conditions in the region of Andika in Khuzestan Province, building underground dams may be an appropriate strategy to offset water shortage during the dry months of the year because construction of such dams in this region entails low costs and the dams will have acceptable efficiency. Many criteria and factors with different degrees of importance are involved in locating underground damsites. Therefore, synchronization of the geographic information system (because of its high capability in analyzing spatial data) and analytic hierarchy process was used to study and apply the role played by each of the mentioned factors (while considering the degrees of their influence in selecting the suitable sites), and the desired results were obtained. The present research used a decision tree that included the reservoir and economic criteria each with its own subcriteria. For the reservoir factor the four subcriteria of slope, hydraulic conductivity, effective porosity, and permeability of dam foundations and for the economic factor the two subcriteria of damsite and its distance from the water use location were considered. Twenty seven sites were initially selected to determine dam axes at the desired sites. The positions of the selected sites were then considered on the map and the spatial priorities of 15 sites were introduced. Finally, the storage volume of each proposed priority was calculated.