Groundwater suitability in Tashk-Bakhtegan and Maharloo basin, Iran

In the present study, groundwater quality evaluation for drinking and irrigation purposes in Tashk-Bakhtegan and Maharloo basin was investigated using the data from 420 observation wells.

To assess the suitability of groundwater in terms of 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) and to calculate the Drinking Water Quality Index (DWQI) and Irrigation Water Quality Index (IWQI) were used.

The results showed that groundwater quality for drinking purpose varied widely across the basin, with the average DWQI value increasing from 238.83 in November 2017 to 249.79 in May 2018. IWQI results also indicated that in most areas, especially in the northern and southern parts 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, indicating a slight increase in groundwater quality for agricultural use.

According to the obtained results, necessary precautions should be taken for groundwater before using it for different purposes, and the results of this study can be used in the planning and management of groundwater resources.