EXAMINING THE RESPONSE OF THREE BURIED VALLEY AQUIFERS TO LARGE SCALE WATER EXTRACTION

The sole source of water for the City of Edmonton, Alberta is the North Saskatchewan River (NSR), which originates in the Rocky Mountains. To build resilience against potential water scarcity due to climate change or contamination events, local groundwater is being considered as an alternative and emergency water source. Groundwater may provide a possible secondary source to augment water supply in drought, and a temporary solution in the event of upstream contamination in the NSR. Our recent research has delineated pre-glacial buried valleys close to the City of Edmonton, Canada that may contain large quantities of groundwater. These buried valleys host saturated sand and gravel that form aquifers, which are tapped locally as a water source. However, little is known about their capacity to supply larger water volumes. This study utilizes a numerical groundwater flow model (MODFLOW) to examine different pumping scenarios for three buried valley aquifers in the Edmonton area. Unique hydrogeological responses to pumping were observed in each buried valley aquifer, which establishes a first order regional scale hierarchization and characterization. Additionally, we constrained the maximum extractable volumes of water under idealized conditions to create a framework for future investigations into groundwater resources in the area. Knowledge of the response of the groundwater system to pumping scenarios will enable better informed decision-making for future groundwater resources decisions in Edmonton and elsewhere.