An integrated investigation of groundwater-surface-water interactions under conditions of changing climate in the Great Lakes Basin

Abstract

Fluctuations in temperature and precipitation associated with changing climate have the potential to influence hydrologic components, such as the timing and amount of groundwater recharge as well as temporal patterns in stream base flow. Variations in such factors may impact ecological functioning and human activities within a watershed, especially in water stressed, agriculturally dominated regions of the Great Lakes Basin. The potential impacts of climate change and subsequent feedback mechanisms are best examined through an integrated monitoring and modelling approach. In this manner, an improved understanding of a watershed's hydro-climatic functioning, especially groundwater-surface water interactions, may be obtained through multi-faceted, field based data collection and further supported by integrated numerical modelling. This research presents the Upper Parkhill Watershed in southwestern, Ontario (jurisdiction of the Ausable Bayfield Conservation Authority) as the location of an ongoing integrated investigation. This watershed features an Integrated Water and Climate Monitoring Station that has been collecting continuous data since 2012. Measurements from this station have been supplemented by site characterization as well as a water sampling program examining groundwater tracers, such as 222-Radon and electrical conductivity, in addition to stable isotopes (18O and 2H) and tritium to respectively assess locations of groundwater discharge, water origin, and age. This research supports the creation of an improved hydrogeologic conceptual model from which groundwater-surface water dynamics will be evaluated in the context of historical and potential future climate variability. It is anticipated that this study will provide a framework for the use of data from integrated monitoring stations and will also help to identify data gaps and variables of greatest importance for the purposes of integrated modelling.