Geochemical Assessment of Groundwater Suitability for Drinking and Irrigation Purposes in the Mamozin Watershed, Duhok Governorate, Northern Iraq

Groundwater is vital for drinking and irrigation needs worldwide, emphasizing its major role in sustainable development. Monitoring groundwater quality is critical, particularly in rural areas, where it serves as a key resource, to avoid the potential health and economic repercussions of water contamination. The wells of the Mamozin watershed, located southeast of Duhok City, are an essential groundwater resource for the local population, providing both drinking and irrigation fulfillment. Therefore, this research focuses on a geochemical assessment of groundwater suitability for drinking and irrigation purposes in the fourteen wells of the Mamozin watershed during the spring season (May 2025). Various indicators were used to assess the groundwater suitability. For drinking suitability, the potential of hydrogen (pH), total dissolved solids, total hardness, and water quality index indicators were used. The values for these parameters were given as pH (7.1-7.5), total dissolved solids (346.01-713.39 mg/L), total hardness (215.45-459.31 mg/L as CaCO₃), and water quality index (30.58-61.42). For irrigation suitability, the sodium adsorption ratio, sodium soluble content (Na%), residual sodium carbonate, permeability index, and Wilcox classification 1955, were used. The results were given as sodium adsorption ratio (0.03 to 0.48), Na% (1.30 to 10.59%), residual sodium carbonate (-3.17 to -0.90 meq/L), permeability index (34.24 to 43.46%), and Wilcox classification was found to be (excellent to permissible water). According to all these indicators, it has been determined that the groundwater in the study area meets the necessary standards for both drinking and irrigation purposes. The chemical analysis indicated that the cation orders were as Ca²⁺ > Mg²⁺ > Na⁺ > K⁺ while the anion arrangements were as HCO₃⁻ > SO₄²⁻ > NO₃⁻ > Cl⁻. However, the groundwater was classified as the Ca–Mg–HCO₃ type of freshly recharged groundwater, which influenced by rock-water interactions. The statistical analysis, on the other hand, indicated that the natural geological factors (90.389%) is significantly influenced the groundwater geochemistry in the study area through rock-water interactions.