From Unmodelable to Understandable: A Model Agnostic Approach in Prairie Pothole Hydrology

Modelling the streamflow of flat, and pothole-dominated prairie or arctic regions presents challenges due to the influence of variable Non-Contributing Areas (NCAs) on converting local runoff to streamflow. Various models have been developed to represent these NCAs and their impact on streamflow prediction. However, these models may not adequately capture NCAs dynamics, rely heavily on calibration, are not applicable to large-scale basins, or are not model agnostic. In response, we introduce an open-source and model-agnostic version of a revised Hysteretic Depressional Storage (HDS) model. This model incorporates an improved numerical solution that accurately captures the hysteretic relationships of prairie potholes and NCAs, and their effect on streamflow generation. The revised HDS model is implemented and tested in three hydrological models (HYPE, MESH, and SUMMA) on a prairie pothole basin in Canada. Results demonstrate enhanced simulations of streamflow responses in the tested basins. Notably, the modified models successfully replicate the known hysteretic relationships between depressional storage and contributing areas in the region. The open-source HDS implementation approach facilitates integration into hydrologic or land surface modelling systems, enabling improvements in simulating complex hydrology and streamflow patterns globally.