Subsurface Flow Simulations to Determine Potential Areas of Groundwater Dam Using SWAT Model (Case Study: Doroongar Watershed, Dargaz)

Underground dams are structures that block the natural flow of groundwater and causes underground water resources. In this study, at first18 prone area stounderground Dams were identified using Boolean logic and geology parameters, land use, slope, distance from roads and distance from fault. In the discussion of underground dams, subsurface flow has high importance so that if there is not suitable subsurface groundwater flows construction of underground dams may fail even with high costs. Therefore in this study, SWAT model was used to simulate the water balance and subsurface flow in Doroongar watershed andit was identified using those areas which have suitable subsurface flow and this parameter was used to zone and prioritize the prone areas. By running the SWAT model in the Doroongar watershed, in the calibration step, the correlation coefficient, weighted correlation coefficient and NS (Nash Sutcliffe) were calculated 0.77, 0.75 and 0.68, respectively and in the validation step were calculated 0.71, 0.67 and 0.61.The results showed that SWAT model had acceptable performance for simulation in Doroongar watershed. The results of subsurface flow simulation show that north and south parts of the Doroongar watershed has higher subsurface flow ratio to the center parts of the watershed which represents the high potential of these parts to underground dam construction.