Multiscale Modelling of Mountain, Forest and Prairie Basin Hydrology in Alberta using the Cold Regions Hydrological Model
Authors: John Pomeroy, Kevin Shook, Xing Fang, and Tom Brown
The Canadian Prairie region has presented formidable challenges for hydrological models due to its many internal drainages, large depressional storage, variable contributing area, high infiltration rates, wind redistribution of snow, solar radiation dominated snowmelt, frozen soils and low evapo-transpiration rates. The Canadian Rockies have also presented widespread problems to many models because of many of the aforementioned processes and sublimation of intercepted snow, the impact of slope and aspect on the snowmelt energy balance and sub-canopy radiation effects. Realistic hydrological modelling in western Canada has been hampered by attempts to apply models that were developed for well-drained, temperate or humid regions in our often poorly-drained, cold and sub-humid environment. Such model applications often require setting parameters outside of their physically meaningful range in order to compensate for deficiencies in model structure, conceptualisation and parameterisation. The Cold Regions Hydrological Modelling Platform (CRHM) is a modular hydrological model development platform that was created to explore appropriate structural content, adapt model structure to specific process scales, and increase the physical basis of hydrological models. It has been developed based on western Canadian basin research. In CRHM the user assembles a hydrological model from a selection of hydrological process modules (parameterisations). CRHM’s modularity provides the possibility to change process parameterisations from simpler to more complex ones and to emphasize prairie, forest or mountain processes. It is also possible to rapidly update parameterisations as advances in hydrological understanding occur, or to run models in parallel to compare the impact of differing parameterisations, parameter or driving data availability on model results. Recent CRHM advances include integration with the WISKI data management environment. The impact of these parameterisations on the predictive performance of models created with CRHM is discussed using case studies from the prairie and Rocky Mountains in Alberta. For some basins these are the first successful hydrological process simulations ever conducted and can be used to examine hydrological sensitivity to future land use, wetland drainage, drought, flood and climate change scenarios. The next steps are to apply models created from CRHM for these impact scenarios and to couple them to operational, climate and water resource models for a wider variety of applications from small to large scales.
The Canadian Prairie region has presented formidable challenges for hydrological models due to its many internal drainages, large depressional storage, variable contributing area, high infiltration rates, wind redistribution of snow, solar radiation dominated snowmelt, frozen soils and low evapo-transpiration rates. The Canadian Rockies have also presented widespread problems to many models because of many of the aforementioned processes and sublimation of intercepted snow, the impact of slope and aspect on the snowmelt energy balance and sub-canopy radiation effects. Realistic hydrological modelling in western Canada has been hampered by attempts to apply models that were developed for well-drained, temperate or humid regions in our often poorly-drained, cold and sub-humid environment. Such model applications often require setting parameters outside of their physically meaningful range in order to compensate for deficiencies in model structure, conceptualisation and parameterisation. The Cold Regions Hydrological Modelling Platform (CRHM) is a modular hydrological model development platform that was created to explore appropriate structural content, adapt model structure to specific process scales, and increase the physical basis of hydrological models. It has been developed based on western Canadian basin research. In CRHM the user assembles a hydrological model from a selection of hydrological process modules (parameterisations). CRHM’s modularity provides the possibility to change process parameterisations from simpler to more complex ones and to emphasize prairie, forest or mountain processes. It is also possible to rapidly update parameterisations as advances in hydrological understanding occur, or to run models in parallel to compare the impact of differing parameterisations, parameter or driving data availability on model results. Recent CRHM advances include integration with the WISKI data management environment. The impact of these parameterisations on the predictive performance of models created with CRHM is discussed using case studies from the prairie and Rocky Mountains in Alberta. For some basins these are the first successful hydrological process simulations ever conducted and can be used to examine hydrological sensitivity to future land use, wetland drainage, drought, flood and climate change scenarios. The next steps are to apply models created from CRHM for these impact scenarios and to couple them to operational, climate and water resource models for a wider variety of applications from small to large scales.
