Identification of suitable sites for subsurface flow harvesting using underground dam (Case study: Border basins of Torbat-e-Jam County)

Every year, large amounts of the country's water resources leave the country through political borders. Subsurface water is part of these resources that flows on the dry bed of rivers and becomes inaccessible without proper exploitation. Since Iran has many common borders with neighboring countries, it is necessary to pay attention to this issue. One of the appropriate solutions to prevent the outflow of subsurface water from the country is the construction of an underground dam that the first and most important step in the construction of an underground dam is to locate the suitable areas. The purpose of this study is to identify suitable sites for subsurface flow harvesting in the border areas of Torbat-e-Jam County. Therefore, using the analytical hierarchy process (AHP), the effective factors in identification of suitable sites for the underground dam were weighted and potential areas were identified. Finally, through a field visit and considering the issues in the region, suitable areas were determined for the construction of an underground dam. The results show that 26.6% of the study area has lacks subsurface flow harvesting potential. Among the parameters weighted by AHP, geology and slope have the highest weight and the distance from the road has the lowest weight. Furthermore, with the field studies, three suitable points for the construction of an underground dam in the study area were identified. Since locating an underground dam is time consuming and costly, using the AHP can be a good way to reduce the time and cost of locating.