Comparison of classical and developed indexing methods for assessing the groundwater suitability for irrigation

Abstract

Introduction: Several water quality indices exist to evaluate irrigation water quality (IWQ), but they have some limitations. This study attempted to develop a new Overall Irrigation Water Quality Index (Overall IWQIndex) using a rational subindex that is flexible enough and updated to signify irrigation water suitability. It considered the maximum verified desirable and permissible value of parameters, including the hazard class, a modified rating system of parameters in each hazard class, and diversified water parameters that have affected the soil and plants. Materials and Methods: A total of 40 calcite-type groundwater samples were analyzed to evaluate the IWQ using the proposed Overall IWQIndex, some IWQ parameters, and different diagram-based statistical methods. Results: The study results were correlated with each other critically, and finally, the suitability for IWQ was determined. The results revealed that the samples of the postmonsoon and premonsoon felt under the ‘good’ and ‘excellent’ categories, respectively. Conclusion: The study developed an indexing model that is easy to compute, rationalize and deliver accurate information on the suitability of irrigation water.