Investigation of Hydrogeochemical Characteristics and Controlling Processes of Groundwater Using Geochemical Modelling, Ionic Ratios, Water Quality Indices and GIS Techniques in Semi-arid Areas of Northern Ethiopia

Integrated approaches of geochemical modelling, descriptive statistical analysis, water quality indices (WQIs) and geospatial methods were applied to examine the hydrogeochemical characteristics and controlling processes of groundwater in norther Ethiopia. Groundwater’s physico-chemical including major ions, pH, total hardness (TH), soil salinity (EC), total dissolved solids, irrigation water quality indices (IWQIs), and pollution index (PI), from twenty-two samples have been used to evaluate groundwater chemistry. The groundwater is characterized by mainly alkaline freshwater dominating by Ca2+ and HCO3−. The results of ionic ratios revealed that rock-water interaction mainly by weathering of silicate and/or carbonate minerals, ion-exchanges, and human/anthropogenic phenomenon influenced groundwater hydrogeorochemistry. Based on SI, groundwater is under-saturated with reverence to gypsum, CO2, halite, fluorite and anhydrite at all sampling locations, suggesting that the dissolution of these minerals. Most water samples are oversaturated with reverence to aragonite, calcite and dolomite, demonstrating that they are precipitated. High bicarbonate, EC, TH, PI, Ca2+, K+, and Fe2+ values in most water samples prove to be inappropriate for drinking purpose. Groundwater was safe and suitable for irrigation for most IWQIs, while EC and bicarbonate hazards revealed that some groundwater required slight to moderate restriction on use. The thematic maps of most major ions, PI, EC, and TH show that an increased and water quality deteriorated towards the downward directions of the study site. Hence, it is crucial to consider these problems and to implement a constant groundwater chemistry examination program and upgrading of supervision practice for bearable uses of the groundwater.