AquaChem Used to Analyze Groundwater Geochemistry for University of Ottawa Masters Project

April 17, 2015

A student at the University of Ottawa recently used AquaChem water quality analysis software in the completion of a M.Sc. thesis project to better understand the groundwater regime and produce maps of expected groundwater quality for a city in Ontario, Canada.

The project involved the sampling and analysis of groundwater from 127 private wells. Field parameters were recorded at each site and groundwater samples were analyzed for major ions, dissolved gases, dissolved carbon, bacteria, nitrogen parameters, environmental isotopes and trace anions and trace metals.

AquaChem was chosen to manage the water quality data and analyze the geochemistry using the plotting capabilities. A user-defined geochemistry database was created in AquaChem and the data was then used to experiment with plots of different kinds. When analyzing the plots, the connection between the sample view and the plots was very useful to identify points on figures. The figure below shows a Piper plot generated in AquaChem to identify differences between groundwater obtained from different well types. The water type of groundwater drawn from dug wells situated in shallow overburden deposits was calcium bicarbonate, whereas drilled wells situated in deep overburden deposits or bedrock produced sodium water ranging from bicarbonate to chloride. From this plot, the user was able to determine that deep overburden wells behaved similarly to bedrock wells rather than shallow overburden wells. This allowed the wells to be categorized for further analysis and mapping.