Environmental assessment of groundwater quality for irrigation purposes: a case study of Hillah City in Iraq

This study was conducted to evaluate the groundwater quality of wells located around the Hillah city of Iraq, for the purposes of determining its suitability as water for agricultural irrigation, according to the Irrigation Water Quality Index (IWQI). The number of wells that are being investigated was 24. The spatial distribution of water quality parameters was investigated using ArcGIS software. Ten parameters were established for the dry and wet seasons of 2018 and 2019, which include pH, electric conductivity (EC), total dissolved solids (TDS), calcium, potassium, magnesium, bicarbonate, sodium, chloride and sulfuric. The results showed that all pH and sodium absorption ratio values were within the allowable limits. About 69%, and 75% electric conductivity, total dissolved solids, values respectively were higher than the allowable limits. Most values of positive and negative ions were higher than the allowable limits. In 2018, the water quality of (4%) of wells number was classified as moderate restriction and approximately 96% was poor quality in dry season, while the IWQI was enhanced in the wet season. In 2019, the quality of water was dropped as most of the water quality was classified as severe restriction and few in the high restriction for the dry season. These values were increased in the wet season due to the freshwater dilution effect. Water quality index show that a large percentage of the wells have poor water quality leads to severe restriction for irrigation requirements and need relatively high permeability soils and salt-resistant plants.