Groundwater suitability in Tashk-Bakhtegan and Maharloo basin, Iran

Aims: The main goal of the present study is the investigation of the suitability of groundwater for drinking and irrigation consumption in the Tashk-Bakhtegan and Maharloo basin based on the data from 420 observation wells. Materials Methods: Hydrogeochemical parameters including Potassium (K+), Sodium (Na+), Magnesium (Mg2+), Calcium (Ca2+), Chloride (Cl-), Bicarbonate (HCO3), Sulfate (SO42-), Electrical Conductivity (EC) and total soluble solids (TDS) for 420 monitoring wells in November 2017 (as a dry month) and May 2018 (as a wet month) were used to estimate Drinking Water Quality Index (DWQI) and Irrigation Water Quality Index (IWQI) for determining the suitability of groundwater. Findings: The results indicated that groundwater quality for drinking consumption varied widely across the basin and the mean value of DWQI increased from 238.83 in November 2017 to 249.79 in May 2018. IWQI results indicated that in most areas, especially on the north and south side of the basin, groundwater has moderate, high, and severe limitations for agricultural activities in both months. The average value of IWQI increased from 47.67 in November 2017, to 49.67 in May 2018, reflecting a slight increase in groundwater quality for agricultural uses. Conclusion: According to the obtained results, it can be said that necessary precautions should be taken for groundwater before using it for different purposes, and the results can be utilized in the management and organization of groundwater resources.