Assessment and Management of Drainage Water Quality for Reuse in Irrigation Projects

ABSTRACT Nowadays, with the increase of the demand for freshwater used to irrigate the agricultural lands, in the exchange for the severe shortage in the sources of the freshwater supply, the finding of alternatives becomes persistent need to compensate this shortage. One of the important alternatives is the reuse of the drainage water for irrigation. In the present study, the quality of the agricultural drainage water of the Al-Husseiniya irrigation project of Karbala governorate in Iraq is assessed and managed in order to reuse this water for irrigation. The Brazilian Water Quality Index (IWQI) model is used to evaluate the quality of the drainage water and the river water within the study area. As well, the quality of drainage water of six selected stations is improved by blending this water with the river water by using nine blending ratios. It is found that 75% of the values of the IWQI classification category of the drainage water are within the category of severe restriction, SR, and 25% of these values are within the category of high restriction, HR. Also, the results showed that the river water quality is within the IWQI category of low restriction, LR. Graphical abstarctLayout of Al-Hussainiyah irrigation project (a), and (b) The monthly variation of the (IWQI) values of various stations.