CLIMATE CHANGE ASSESSMENT OVER THE ASSINIBOINE DELTA AQUIFER

How will climate change impact Canada's groundwater resources? The answer is not clear. It has, however, been widely accepted that climate change will have an impact on the atmosphere (IISD, 2001). To assess these atmospheric changes on groundwater resources (and how we might adapt to them) a multi-disciplinary study based on large sand and gravel aquifer system known as the Assiniboine Delta Aquifer (ADA) is being conducted. The generalized approach will be to use physically based mathematical models of both the land surface and groundwater systems to predict changes in water quantity given drivers of future atmospheric climate and adaptive behaviors dictated by value-based economic analysis. Research efforts intended to understand the interaction between General Circulation Models (GCM) are progressing with computational methods, and hydrologic models are components of paramount importance in water resources management as well as in climate change assessment. Here the groundwater model MODFLOW that simulates the 3D groundwater flow by using a finite difference method is coupled together with the Canadian Land Surface Scheme CLASS for representing the water flow in the saturated and unsaturated zones of the porous medium respectively. CLASS follows Darcy's law of moisture fluxes and simulates the mean temperature, liquid water and ice contents in three soil layers. The two models are linked and run within the parallelized world of a componentized coupler. The complete set of linked codes is used to simulate a number of synthetic examples in both sequential and concurrent modes. Finally, it is used to model the hydrological water cycle in the Assiniboine Delta Aquifer, dealing with field data processed by Geographic Information Systems. Another purpose of our work and code development is to provide accurate planetary boundary layer conditions for the atmospheric model, in order to improve the short and long term climate forecasts over the Prairies.