Using The Canadian Method to Classify Irrigation Water Quality Index for Shatt Al- Kufa River Section (Al–Zerkh to Al–Qadisiya)


Shatt Al-Kufa ( Kufa River) is the main supply of surface waters in Najaf, it is necessary to concern about the river water quality because of increasing demand for different using. This study aims to find the Water Quality Index ( WQI) for irrigation use at many locations on Shatt Al-Kufa within the study section of the river. Nine water quality parameters: Sulfate (SO4 -2), Chlorides ( Cl-1), Total Dissolved Solid (TDS), Electrical Conductivity (EC), Hydrogen Power ( pH), Calcium (Ca+2 ), Magnesium ( Mg+2 ), Sodium (Na+ ), and Potassium ( K+) were studied over ten months ( January- October 2014) for nine locations along the study section. Sodium Adsorption Ratio ( SAR) and Soluble Sodium Percentage ( SSP) were also calculated. Firstly Food Agricultural Organization ( FAO, 1985) was adopted to evaluate the suitability of water for irrigation use. Then Canadian Water Quality Index ( CWQI ) was applied to classify the water quality index of the river for irrigation. It is found that the mean values of parameters for all selected locations are within the highest allowable limits of FAO classification for irrigation, with respect to the values of ( SAR ) the results showed that the water samples were within the level ( S1 ) which there was no harmful effects from sodium, while ( SSP ) values ( except one value ) fall within the water class of good according to Todd classification of irrigation water based on SSP. Results of the annual and seasonal average water quality indices according to the Canadian method were classified as Fair ( 65 – 79 ) in all selected locations. The effective reason which decrease the water quality index, was the presence of high values of ( EC ) and high concentrations of ( TDS ) in all locations, which it refers to high concentrations of salts. Approximately 100 % of EC and TDS water samples have concentrations that exceeded the permissible limits for irrigation water.