Groundwater Quality and Appropriateness for Drinking and Agriculture Purposes Using Water Quality Indices and Multivariate Statistical Analysis in Kombolcha City, Ethiopia

Abstract

The study used an integrated method of water quality indices (WQIs) and multivariate statistical analysis to evaluate the hydrogeochemical characteristics of groundwater samples and their appropriateness for drinking and agricultural applications in Kombolcha City. The hydrogeochemical parameters from 17 water samples were examined using standard methods. The WQI, irrigation indices, and geographical information systems (GISs) were used to determine groundwater suitability for various purposes and the spatial distribution of major ions. The study also utilized multivariate statistical methods, including principal component analysis (PCA) and cluster analysis (CA), to evaluate complex groundwater quality datasets. The results revealed that all hydrogeochemical characteristics were in line with Ethiopian drinking water standards and WHO drinking water guidelines. The WQI indicates that 94% of the samples are in excellent condition, whereas about 6% are in acceptable drinking water conditions in the study area’s southern and central regions with considerable agricultural and industrial activities. The Ca²⁺-HCO₃⁻ facies comprise about 53% of the shallow aquifer, and the remaining samples are found in the Ca²⁺-Mg²⁺-Cl⁻ and Ca²⁺-Na⁺-HCO₃⁻–type facies. SAR, Na%, PI, and MAR indicators showed that most water samples are very good to moderately suitable for agricultural use. CA uses dendrogram plots to group groundwater characteristics and sample locations into three groups based on common groundwater features. The study concluded that the combination of WQI, multivariate statistical, and GIS is a viable approach for prioritizing groundwater mitigation and monitoring efforts in Ethiopia’s semiarid regions of the Awash River basin.