Development of an integrated irrigation water quality index (IIWQIndex) model

There are many irrigation water quality indices used to assess water suitability, despite some of their limitations. Hence, it is imperative to develop a water quality index to evaluate the irrigation water more accurately. This study has aimed to emerge an Integrated Irrigation Water Quality Index (IIWQ(Index)) using the sub-index and aggregated equations. This proposed index model was considered to be improved and updated in four aspects: the verified desirable and permissible value of parameters, maximum hazard class, used a modified rating system of parameters, and diversified parameters were considered. The proposed IIWQ(Index) model classified irrigation water into five categories, i.e., rejection, poor, moderate, good, and excellent. This model assessed two types of water to justify the model by categorizing the irrigation waters. The calculated results showed that the index values were 75.77 and 36.51, and the water category fell under 'good' and 'rejected' for the calcite (Ca-HCO3) and sodic (Na-Cl) water, respectively. Besides, this index model satisfactorily evaluated different types of water datasets of eight geographic locations in the world. The study illustrated that the IIWQ(Index) evaluated values and water categories were rational and exhaustive to predict the suitability of irrigation water.