"Technical Report" Suitable Site Selection for Sub Surface Dams Construction Using GIS/RS (Case Study: Ghori Chai River Watershed)

Construction of underground dams as a new task in water resources management especially in arid and semi-arid regions of our country has received considerable attention recently. Outlet of large basins may be suitable places for constructing of underground dams according to appropriate topography and slope characteristics. However finding of suitable locations for constructing the underground dams in large areas is another important task in order to improve management of water resources. Here, the Ghori Chai basin, which is one of the large basins in Ardabil province was selected as a case study In this research, after introducing different methods for weighting and prioritizing effective factors in finding suitable locations for construction of underground dams, a new weighting method namely, weighting matrix that is based on statistics analysis and Queen function was applied along with the remote sensing (RS) methods and geographic information systems (GIS). The weighting matrix method is based on statistical analysis and equal weighting for all the factors in the study area, by preparing layers of slope, land use, geology, imaging layers of alluvium depth and water table level using the inverse distance interpolation method, and then incorporating the generated layers, the final layer is obtained. This layer provides the appropriate prioritization and location of underground dams at the level of 79,260 hectares of the basin by combining layers that are prepared independently and with the same weight and in the form of homogeneous units. The standard classification method has been used for prioritization.