Providing a scientific basis for water management policy, and assessing the physical characteristics underlying hydrologic risk, typically requires watershed-scale assessments that encompass a few hundred km2 at a minimum. However, agriculture-focused water resources challenges often encompass much larger areas, and can easily extend to major river basins (>100,000 km2). Given the recent increase in crop losses attributed to large-scale extreme climate related events (i.e. overland pluvial flooding, excess moisture, and drought), and the concern that the frequency of these events will progressively increase in response to climate change, there is growing demand for large-scale hydrologic risk assessments. Because of complex interactions between climate, surface water, groundwater, and soil moisture across much of the agricultural landscape, robust physically-based 3-D integrated hydrologic models provide a holistic means of performing water related risk assessment for these types of applications.
In this presentation we discuss a large-scale modelling-based agricultural risk assessment project whereby fully-integrated surface/subsurface water models are being developed using the HydroGeoSphere platform for the South Saskatchewan River Basin (SSRB, ~150,000 km2) located in the predominately arid region of Western Canada. The hydrologic responses within its major sub-basins are nested seamlessly within the full-basin scale model in order to capture additional details at an increased resolution.
Results from this work demonstrate that comprehensive physically-based hydrologic simulation platforms are becoming increasingly relevant and feasible tools for addressing water related challenges facing global agriculture. Visualization of transient model results includes spatially-distributed soil moisture, groundwater levels, recharge and discharge patterns at high resolution in relation to surface topographic controls and water bodies.
Once complete, the SSRB modelling platform will facilitate large-scale spatially-distributed projections of flood, drought, and other water-related risks to crop production at unprecedented detail, over temporal intervals ranging from days to decades.