Salwan S. Al-Hasnawi, Ahmed S. Al-Zubedi
Groundwater provides is a crucial supply of drinking water in semi-arid regions where surface water is scarce and unreliable. Groundwater quality in the north-central Iraq effected by complex geological and hydrogeological conditions, spatially integrated assessments remain limited. The present study assesses the suitability of groundwater for drinking in the area between Tikrit and Baiji, Salah Al-Din Governorate, through combining hydro-chemical analysis with the Weighted Arithmetic met Water Quality Index and Geographic Information System techniques. Water samples taken from 33 groundwater wells, scattered in the study area,were analyzed to determine the major physical and chemical parameters which then evaluated basedon World Health Organization guidelines for drinking water. The calculated values of WAWQIwere used to classify groundwater quality, and Inverse Distance Weighting interpolation was used to examine spatial variability over the study area. The results show that most samples are fall within the poor to unsuitable categories for drinking, largely due to high concentrations of total dissolved solids, namely: sulfate, nitrate and sodium. Spatial patterns of groundwater quality reflect variations in lithology and structurally controlled hydrogeological conditions within the Injana aquifer system. The integrated Weighted Arithmetic Water Quality Index-Geographic Information System approach offers a practical basis for identifying areas of groundwater quality degradation and supports informed groundwater management in semi-arid environments.