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Abstract

Water is vital, but population increase and climate change have caused water scarcity issues. Managed AquiferRecharge (MAR) can help replenish the aquifers in various ways. The study evaluates a few types of MARs and their impact in the city of Guelph, Ontario, Canada, using MODFLOW. Guelph mainly relies on fractured dolostone aquifers to fulfill its population's water needs, and a future rise in water demand could cause a water shortage. A MODFLOW model comprising three 10 m layers to represent the 30 m deep Guelph Formation aquifer. Hydraulic conductivities due to sand dominance are given 35, 20, and 10 m/day values from top to bottom layers, respectively. Recharge rate and boundary conditions are defined based on the site data analysis. The steady-state model shows that the highest head values are in the North region of the study area, and the lowest is in the middle region. A drought scenario was developed by decreasing recharge and increasing pumping rate for three years, resulting in an average 4m head drop. MAR was implemented for the next three years using an infiltration basin, and five injection wells resulted in a 5 m rise in the head only in the areas where MAR systems were installed. Furthermore, the spread of contamination into most of the domains occurred in three-year MAR activity areas due to various contamination sources. Overall, MAR demonstrated the potential to increase the water table and contamination vulnerability. With proper management, MAR could assist in long-term groundwater sustainability.