Characterizing and quantifying aquifer-wetland interactions

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Wetlands are groundwater dependent to varying extents but the processes that control their groundwater dependency are poorly understood. Wetlands and aquifers are undergoing increasing anthropogenic and climate change pressures which have led to unprecedented perturbations throughout the world. Managers and policy makers have an urgent need for improved knowledge of the nature and extent of aquifer-wetland links to support better management and conservation of both entities. The aim of the proposed research is to improve our understanding of how wetlands (riparian marshes, isolated marshes and swamps, and peatlands) are dependent on groundwater, and vice-versa, in glaciated environments such as those found in eastern Canada and southern Quebec. The proposed research program is designed to tackle three major goals: 1) better understand exchange mechanisms responsible for the interactions; 2) measure flows and characterize exchange conditions between aquifers and wetlands; 3) develop a framework for quantitative approaches to estimate aquifer-wetland links. In Theme 1, a new landscape-wide network of 50 instrumented wetlands will be developed in southern Quebec. The hydrogeologic settings of each wetland will be characterized, along with its geochemistry. Five wetlands will be more intensively instrumented to allow finer analysis of aquifer-wetland interactions. Regional scale mapping of groundwater dependent wetlands will be performed. In Theme 2, a framework will be developed for using quantitative approaches. Two fully-coupled surface and groundwater flow models will be tested at the regional scale. A detailed modeling study will be performed for the five more instrumented wetlands. A management water budget tool will be developed for screening analyses. The originality of this research program stems from the variety of wetlands studied, from the breadth of geological conditions in glaciated terrain and from a combination of field, laboratory and modeling approaches. The research program will bring entirely new contributions to our knowledge of wetlands. These contributions have the potential to change dramatically the way groundwater and wetlands are managed.