SIMULATING THE EFFECTS OF LAND USE AND CLIMATE CHANGE ON HYDROLOGIC FLOW AND TRANSPORT USING A FULLY-INTEGRATED SURFACE/SUBSURFACE MODEL

Both climate and land use changes can affect the sustainability of water resources. Field studies and modeling efforts have provided valuable information regarding the impacts of these changes on surface water and groundwater resources. However, the use of physically-based fully-integrated hydrologic models to explore the entire hydrologic system in a holistic manner under climate and land use change has only just emerged. This type of modeling framework can be used to quantitatively evaluate the impact of both climate and land use changes on surface and subsurface hydrology, contaminant and thermal energy transport, and the interactions between the surface and subsurface flow and transport regimes. In this work, the 3D model HydroGeoSphere is used to illustrate the variations in groundwater-surface water interactions as a result of climate and land use changes, and the importance of these interactions on the quantity and quality of surface water and groundwater. Results from numerical simulations of a river basin in North-central Kansas, in addition to a stream section in Southern Ontario, Canada will be presented to demonstrate the effects of climate and land use change across a variety of scales and environments. Changes in air temperature and precipitation quantities and patterns guided by IPCC Global Climate Model outputs are simulated and compared to results from simulations using current climatic conditions. Changes in land use representing increased urbanization and increased agricultural activity will also be simulated. This research highlights the need for a holistic approach when predicting the impacts of both natural and anthropogenic activities on the sustainability of water resources.