Testing the ability of a semi-distributed hydrological model to simulate streamflow and contributing area relationships in cold regions

English Abstract:

A dry and cold climate, the prevalence of small depressions, and the lack of a well-developed drainage network are characteristics of environments with extremely variable contributing areas to runoff. These types of regions (e.g., the Prairie Pothole Region (PPR) of North America) arguably present the greatest challenge to properly understanding catchment streamflow generation processes. Previous studies from all types of regions have shown that contributing area dynamics are important for streamflow response, but the nature of the relationship between the two is not typically quantified. Furthermore, it is not known if hydrological models can properly represent contributing area while simulating streamflow. In this study, the relationship between streamflow and contributing area was first characterized using field and remote sensing measurements. We then tested the capacity of the PDMROF configuration of Environment Canada’s MESH model to reproduce this relationship. The study focused on the St. Denis Creek watershed in central Saskatchewan, Canada, which with its considerable topographic depressions can be considered representative of much of the PPR, making it ideal for this type of investigation. Streamflow tended to scale with contributing area according to power law relationships (R² >0.75, p <0.001) for both model and remote sensing methodologies, and were in good agreement with each other. Ongoing challenges in defining quantitative relationships between streamflow and contributing area include data collection, and demonstrable hysteresis and spatial variation in the relationship among watersheds.