Groundwater Potential Mapping Using Frequency Ratio and Statistical Index Models at Dehloran and Mosian-Abdanan Plains ,Iran

Identifying areas with high potentials for groundwater is a major factor for the management of groundwater resources. In this study, we tried to identify areas with the potentials for groundwater   in Dehloran  and Mosian-Abdanan  plains, Ilam, by using frequency ratio and statistical index  models. Conditioning Factors used in this study include: Groundwater levels, Lithology, geomorphology, slope, slope aspect, drainage density, land use, elevation, topographic wetness index, curvature, and texture of the soil. In the frequency ratio and statistical index  models, at first wells with a discharge rate of 10 cubic meters per hour were extracted in the region; then, 70 percent Training wells (253 pcs) and 30% of the wells for validation (108 pcs) were randomly selected and divided and based on the frequency ratio, necessary analyses were conducted in classes and maps and maps were overlapped and, finally, the groundwater resources map  for each of the models were produced. ROC curve method was used to evaluate the performance of models. The results showed that the  frequency ratio and statistical index models 99 and 93 percent respectively have excellent efficiency in finding potential sources of groundwater in the plains of Ilam province, Dehloran, and Musian_Abdanan. Based on the model results, Frequency Ratio model functions better than Statistical Index. Based on this, the percentage of the area achieved in the Frequency model ratio are as follows 36% of the areas were Very weak; 15% Weak; 12% Average; 19% Good, and 18% Very good. It is suggested that respected Managers  use Frequency Ratio model  in their own programs.