The Choice of Location of Underground Dams Using Multi-Criteria Decision-Making Methods TOPSIS and GIS in the Eastern Part of the Watershed of Gorganroud

Groundwater dams are structures that have the ability to block subcortical water, retain water in local aquifers or divert water to adjacent aquifers, raise groundwater levels, store and make available groundwater. Taking into account the environmental and socio-economic benefits of underground dams, proper location is the first step in the construction of these dams. New and innovative methods for correct location reduce the risks associated with improper location and construction of underground dams. For this purpose, in this research, through the use of multi-criteria decision-making methods along with the high capabilities of ArcGIS software, suitable location of underground dams in the eastern part of Gorganrood watershed in Golestan province has been done.

Criteria were considered including slope, drainage, geology, topography, land use, fault, soil texture, and positions of village. The Analytic Hierarchy Process (AHP) is used to weighting the criteria. Then the TOPSIS technique is used to integrate criteria maps and locating underground dams.

A consistency rate of 0.03, showed a relatively high accuracy of weighting process. Considering the normal weights, slope and positions of village were found to be the most and the least effective criteria, respectively. The results showed that the study area is classified into four categories for constructing underground dams: very suitable, suitable, partly suitable and unsuitable. The unsuitable category has the highest percentage of the surface area (76.7 percent) and the very suitable category has the lowest percentage of the surface area (2.1 percent).

In conclusion, with considering high capacities of multiple-criteria decision-making methods and GIS in locating underground dams, as expert opinions are more accurate and data are newer and it is more possible to get better results from these techniques and tools.