Impacts of climate change on groundwater in the Great Lakes Basin: A review

Climate change has the potential to alter the physical and chemical properties of water in the Great Lakes Basin, in turn impacting ecological function. This study synthesizes existing research associated with the potential effects of a changing climate on the quality and quantity of groundwater in the Great Lakes Basin. It includes analyses of impacts on (1) recharge, (2) groundwater storage, (3) discharge and groundwater-surface water (GW-SW) interactions, (4) exacerbating future urban development impacts on groundwater, (5) groundwater quality, and (6) ecohydrology.Large spatial and temporal (i.e., seasonal) variability in groundwater response to climate change between regions is anticipated. Most studies combine field observations with modelling, but many have focused only on small/medium basins. At these small scales, groundwater systems are generally projected to be fairly resilient to climate change impacts. However, modelling studies of larger basins (e.g., Grand River, Saginaw Bay, Maumee River) predict an increase in groundwater storage. Uncertainty in model simulations, particularly from climate models that are used to force hydrological models, is a major challenge. There have been too few studies to date that investigate the interplay of climate change and groundwater quality in the Great Lakes Basin to draw conclusions about future groundwater quality and ecohydrology.A summary of methods, models, and technology is provided. Model uncertainty has become an increasingly important topic and is also discussed. The study concludes with a synthesis of the main science needs to understand groundwater impacts in order to adapt to a changing climate in the Great Lakes Basin.