PAIRING TEMPERATURE DATA WITH FULLY-INTEGRATED HYDROLOGIC MODELS TO PROVIDE INSIGHT INTO GROUNDWATER-SURFACE WATER INTERACTIONS

Many of the physical, geochemical, biological and ecological processes that help shape our natural and manmade environments are dependent upon water temperature. New abilities to collect spatially and temporally extensive water temperature data have enabled researchers to better understand these processes and the relationships between them. Pairing these extensive temperature datasets with numerical models capable of surface/subsurface flow and heat transport can provide more insight into the interactions between surface water and groundwater, and the mechanisms that control water temperature. In this work, HydroGeoSphere, a fully-integrated hydrologic model capable of surface/subsurface flow and heat transport is paired with temperature data for a local-scale field site in Ontario, Canada to investigate underlying processes that drive the flow and thermal transport system, and their sensitivity to changes in the environment. The conclusions from these simulations are then tested in larger scale regional simulations of a watershed in north-central Kansas, USA. Some results from this research indicate that the location and quantity of groundwater discharge is sensitive to changes in streambed morphology and topography, which changes temporally with erosion and sedimentation. It has also shown that the sensitivity of stream and streambed temperature to changes in air temperature, and diurnal temperature variations, is influenced by the quantity of groundwater discharge. This links the sensitivity of the stream and streambed temperatures to changing climatic conditions to erosion and sedimentation processes. Overall, the use of extensive surface water and groundwater temperature datasets in fully-integrated hydrologic models capable of heat transport provide further insight into the flow and transport regime of the entire hydrologic system.