Hydrochemical Assessment of Tigris River for Irrigation Purposes within Baghdad Province, Iraq

The aims of this study are (1) to determine whether Tigris River water is suitable for irrigation using specific irrigation indices. (2) Analysis of thirteen hydrochemical parameters, including pH, EC, TDS, , , , , , , , , TA and as total hardness. Also, seven irrigation water quality indices were used: Magnesium Hazard (MH), Kelly's Index (KI), Sodium Adsorption Ratio (SAR), Sodium Percentage (Na%), Soluble Sodium Percentage (SSP), Potential Salinity (PS), and Sodium Hazard (SH), supported by the most specific irrigation diagrams (Piper, USSL and Wilcox). Samples were taken monthly from twelve different sites along the river for two consecutive years (2021-2022). The results revealed that the water is suitable for irrigation chemically according to SAR, Na%, SSP, KI, and MH, except for PS due to high levels of sulfate and chloride ions. Furthermore, the USSL diagram indicated Irrigation water quality, that 100% of water samples taken from the Tigris fell into the appropriate class within 2021. While in 2022, 83.33% of samples were within the appropriate class (C3-S1). According to the Wilcox diagram, 91.66% and 83.33% among the water samples within a good class (low sodium and moderate salinity) for two consecutive years