Project leader: Dr. Edward Sudicky, Professor, Department of Earth Sciences; Canada Research Chair in Quantitative Hydrogeology, University of Waterloo

Project team: Researchers are based at the Universities of British Columbia, (Dr. J. Ross), Toronto (Dr. W. Richard Peltier) and Waterloo (Drs. Edward Sudicky and Jonathan Sykes), and at Université Laval (Dr. Rene Therrien). Natural Resources Canada and the US National Center for Atmospheric Research are project partners.

Objective: The goal of this project is to develop a computational modelling framework that couples the US National Center for Atmospheric Research’s (NCAR’s) Climate Community System Model (CCSM4) with HydroGeoSphere, a three-dimensional model of surface and subsurface flow dynamics that has been under development for more than a decade by University of Waterloo and Laval researchers.

Project description: This project integrates an intra‐disciplinary team of researchers in studies of climate change and groundwater resources evaluation. Dr. Sudicky and his team will replace NCAR’s land surface processes module, the one that deals with evapotranspiration, soil moisture and river runoff as well as the depiction through leaf area index of the evolving albedo of the surface, with the HydroGeoSphere model. With their module in place, the team will directly address the effect of global warming on soil moisture, surface water and groundwater conditions at the continental scale and predict more accurately than previously possible the increasing susceptibility of the system to regional changes in precipitation patterns.

The project’s investigators are working with scientists at NCAR to enable coupling of the models, and with researchers at Natural Resources Canada, Earth Sciences Sector, to develop databases of the surficial geology and land use/land cover over the Canadian land mass. They are also performing calculations at a much higher spatial resolution for several watersheds in Ontario and Quebec to demonstrate the utility of the coupled HydroGeoSphere–CCSM4 model to address issues typically confronted by water managers and conservation authorities charged with implementing policy and operational adaptations driven by climate change and related issues such as changes in land use.

Existing climate change models incorporate land surface processes such as hydrologic surface‐water routing, evapotranspiration and shallow infiltration over the first metre or two of the subsurface, but they do not include a groundwater component. This is a major deficiency because, for example, current climate models cannot forecast the impacts of global warming on base flow to streams and rivers fed by groundwater, nor can they accommodate important feedbacks between the groundwater system, the shallower unsaturated zone, and the climatological system. This deficiency is being addressed by this research project.

Climate change will have an impact on future recharge rates and on the underlying groundwater resources. Quantifying the impact is difficult and subject to uncertainties in climate predictions. Groundwater recharge is influenced not only by hydrologic processes, but also by the physical characteristics of the land surface and soil profile. Many climate change studies have focused on modelling the temporal changes in the hydrologic processes and have ignored the spatial variability of physical properties across the study area. While knowing the average change in recharge and groundwater levels over time is important, these changes will not occur equally over a regional catchment or watershed. Long-term water resource planning requires both spatial and temporal information on groundwater recharge to properly manage not only water use and exploitation, but also land use allocation and development. Studies concerned with climate change should therefore also consider the spatial change in groundwater recharge because of future changes in hydrologic processes.

The results of these modelling efforts will lead to important data maps on soil moisture conditions, river flows, groundwater recharge rates and groundwater aquifer conditions over the Canadian landscape as they might be affected by climate change in the coming decades. These forecasts will be of immense value to water managers and policy-makers who plan adaptations because of climate change.