Site selection for constructing groundwater dams through Boolean logic and AHP method (case study: watershed of Imamzadeh Jafar Gachsaran)

Abstract

In dry and semidry regions, changes in precipitation in terms of time and level have significant fluctuations, which make management of water resources in these regions very important. The aim of this research is to first identify well-suited sites for constructing groundwater dams, such that there is no limitation for constructing such dams in these regions. For this purpose, by benefiting from Boolean logic and using the physiographic, topographic, geological, land-use, fault, and aqueduct criteria, the regions that had no limitation for constructing groundwater dams were determined. Next, using analytical hierarchy process as well as the quantity and quality criteria of water, economic and social, dam reservoir, and land use, the suitable regions for constructing groundwater dams were prioritized. The inconsistency rate in this research was obtained as 0.05. Investigation of the inconsistency rate indicated that the scoring performed for the criteria and sub-criteria studied here was acceptable. The results of prioritization of the region showed that the watershed slope is one of the most important criteria in determining suitable regions for constructing groundwater dams, and constructing dams at high slopes is not economical. The watershed slope to construct groundwater dams has been studied across all investigations dealing with site selection for groundwater dams. In this regard, the maximum slope for constructing groundwater dams has been considered as 5%. Furthermore, given the geological conditions of the region and high score of this criterion in constructing groundwater dams, this criterion should be paid more attention to in groundwater dam construction. Overall, the results indicated that the regions located in the western and central parts of the watershed had a higher score for groundwater dam construction. Considering the importance of groundwater dam in dry and semidry regions, it can be stated that by constructing groundwater dam in these regions, it is possible to improve the situation of water resources in the region.