Assessing the suitability of water for irrigation purposes using irrigation water quality indices in the Irob catchment, Tigray, Northern Ethiopia

ABSTRACT Irrigation alleviates poverty in arid and semi-arid regions, such as Ethiopia, necessitating a water suitability assessment. This study evaluates irrigation water quality in the Irob catchment, Northern Ethiopia. It differs by using combined parameters of the irrigation water quality index (IWQI) for comprehensive assessment beyond standard comparisons. Eighteen water samples were collected and analyzed using ultraviolet spectrometry, titration, and atomic absorption spectrometry. The evaluation considered electrical conductivity (EC), total dissolved solids (TDS), total hardness (TH), sodium adsorption ratio, sodium percentage, residual sodium carbonate, permeability index, magnesium ratio, Kelley's index, potential salinity, and the IWQI. The findings revealed that 22.2, 38.9, 88.8, 66.7, 83.3, 66.7, 100, 72.2, and 55.6% of samples exceeded recommended standards for EC, TDS, TH, permeability index, manganese, cobalt, copper, cadmium, and nickel, respectively. Most water quality parameters meet standards, but improved irrigation management is crucial to reduce risks. The IWQI indicates that 22.2% of water samples have minor restrictions, while 77.8% have no restrictions. This method provides key insights for evaluating irrigation water quality in similar hydrogeological and environmental conditions, particularly in semi-arid and arid regions. The findings enhance the understanding of sustainable water quality, supporting local authorities in developing resilient irrigation strategies for regional agricultural sustainability.