Management of groundwater resources in the Tolga region (south-east Algeria)

This study attempted to assess and map the quality of Tolga's groundwater in order to determine its suitability for human consumption and agricultural use. The results of analyses of the physicochemical parameters of the water samples were compared with WHO potability standards and standard agricultural water quality indices, namely sodium adsorption ratio SAR ,Soluble sodium percentage Na% , Magnesium risk MH , Kelly ratio KR and permeability index PI. According to the results analysed, most of the physicochemical parameters are above WHO tolerance limits and within the limits of empirical water quality indices for agricultural use. In our study, the graphical maps obtained by kriging are fitted with theoretical variogram models that best approximate the point cloud. The suitability of these models for our sample is verified by cross-validation results. The graphical representation shows high concentrations of conductivity, salinity, calcium, magnesium, sodium, bicarbonate and chloride, which are located in the Eastern part of the region, and increase progressively from northwest to east. These waters are highly charged with salts and have maximum conductivity values.