Evaluation of Water Quality Index of Tigris River for irrigation purposes in Amara city, Southern Iraq

The aim of the study was to determine the suitability of water for irrigation on the basis of the quality indices. The study was performed during the period October to December,2012. The quality of water was assessed by testing parameters such as sodium [Na+], calcium [Ca++], magnesium [Mg++], bicarbonate [HCO3-] and chloride [Cl-]. The quality indices were evaluated and ranged as Electrical Conductivity (EC) [97.0 to 115.0 µS.cm-1], Total Dissolved Solid (TDS) [49.4 to 61.7 mg.l-1], Sodium Adsorption Ratio (SAR) [3.63 to 4.41 meq.l-1], Residual Sodium Carbonate (RSC) [-6.91 to -8.69 meq.l-1 ], Kelly's Index (KI) [0.78 to 0.96 meq.l-1], Permeability Index (PI) [58.07 to 63.48%] and Magnesium Ratio (MR) [22.39 to 37.44%]. The results were compared to the USEPA standard. All the water quality indices were suitable for irrigation. The calculated indices were well in agreement with USEPA. Waters of Tigris River were found within the permissible limits for irrigation purposes.