Groundwater–Surface Water Interaction: Process Understanding, Conceptualization and Modelling (Proceedings of Symposium HS1002 at IUGG2007, Perugia, July 2007). IAHS Publ. 321, 2008, 117-123.

Analysis of thermal stream loadings in a fully-integrated surface/subsurface modelling framework

A. E. Brookfield, E. A. Sudicky & Y.-J. Park

Department of Earth and Environmental Sciences, University of Waterloo, 200 University Ave. W. Waterloo,
Ontario N2L 3G1, Canada

aebrookf@scimail.uwaterloo.ca

Abstract Over the past several years, increased attention has been directed towards understanding flow, contaminant and thermal transport exchange processes occurring at the interface between surface water and groundwater, particularly in the vicinity of riparian zones in the riverine valleys and within the hyporheic zone. In this paper, we will demonstrate the new capabilities of the HydroGeoSphere model, a recently developed surface/subsurface control-volume finite element model, which enables HydroGeoSphere to simulate these thermal processes. HydroGeoSphere is a fully-coupled 3-D model that can simulate water flow, evapotranspiration and advective-dispersive heat and solute transport over the 2-D land surface, as well as flow and transport processes in the 3-D subsurface under variably-saturated conditions. Full coupling of the surface and subsurface flow regimes is implicitly accomplished by simultaneously solving one system of non-linear discrete equations describing flow and transport in both flow regimes, as well as the water, heat and solute exchange fluxes between continua. The model capabilities and main features are demonstrated with several high-resolution 3-D numerical simulations, which can examine the effect of contaminant and thermal loadings on surface and groundwater quality. The development and application of a comprehensive model is fundamental to the development of sound management and policy strategies for the protection of the environment, for both human and natural ecosystem functioning. A fully-integrated framework utilizing physically-based, watershed-scale modelling tools enables the quantitative assessment of the capacity and the limits of water resource systems, the evaluation of impacts of anthropogenic activities on water quality, and the definition of the conditions needed to maintain a balance between consumptive water use and the needs of natural habitats to maintain aquatic and wetland resources.

Key words thermal; model; modelling; surface; subsurface; integrated; temperature; atmosphere