Assessment of groundwater quality for drinking purpose using GIS based WQI methods, in Koga irrigation

Groundwater is the most important source of freshwater across the world. However, its quality is deteriorating over time due to anthropogenic and natural factors. Koga irrigation scheme is one of the most intensively irrigated areas causing groundwater deterioration. Nonetheless, groundwater quality used for drinking purpose was not properly assessed. Hence, this study was intended to evaluate the groundwater quality used for drinking purposes using GIS-based WQI method. This method considers twelve water quality parameters (Turbidity, TDS, pH, Nitrate, Sulfate, phosphate, Ammonium, Copper, Iron, Fluoride Electric conductivity and thermotolerant coliform). Besides, geostatistical and spatial analyses were used to assess their spatial pattern. Accordingly, the concentration of nitrate, ammonia, turbidity, pH value, and thermotolerant coliform were not within WHO standard. Furthermore, about 64.4% and 35.6% of the irrigation scheme maintain good and poor groundwater quality, respectively. Yet, the area requires further investigation through including additional parameters, and identifying pollution hotspot areas.