Investigation of groundwater resources quality for drinking purposes using GWQI and GIS: A case study of Ottawa City, Ontario, Canada

Evaluating groundwater quality for specific purposes requires accurate quantitative and qualitative management, accessibility to the study area, and knowledge of the governing environmental processes. Groundwater resources are used as a supplementary for drinking water consumption alongside surface water in most countries. The purpose of this study is to investigate the quality of groundwater resources in the city of Ottawa, located in Ontario, Canada, using the Schuler diagram and the Groundwater Quality Index (GWQI). To determine the water quality, the qualitative parameters of groundwater including Ca, Mg, Na, Cl, SO₄, HCO₃, NO₃, F, pH, TDS, TH, and Turbidity were considered in the Schuler diagram and GWQI. Each parameter's classified water quality Map layer is prepared using the Kriging method in the ArcGIS environment. The results of Schuler's diagram indicated that the range of drinking water quality was good to moderate in more than 50% of the investigated groundwater resources. Moreover, the results of the groundwater quality classification map layer based on the GWQI revealed more than 90% of the groundwater resources were examined in the good and excellent range for drinking purposes. Accordingly, these results indicate that the GWQI values in the study area are well within the permissible limits and the quality of the groundwater is suitable for drinking and other inhabitants' consumption.