Landslides Along the Provincial Highways in Southern Saskatchewan (1)

The Saskatchewan Ministry of Highways and Infrastructure (MHI) manages a network of approximately 26,000 km of highways, which includes sections that cross the valley walls and riverbanks. Some valley walls and riverbanks may have failed in the past and are presently at or near equilibrium. In addition, highway construction along riverbanks and valley walls often involves deep cuts and high fill embankments, which are particularly prone to landslide activities. MHI spends several million dollars annually for evaluation, monitoring, and remediation of these landslides.

MHI has implemented an annual geo-hazard program to monitor and evaluate its geo-hazard including the landslide hazards. Landslides in southern Saskatchewan can generally result from combination of the various causes including: ground conditions (sheared shale materials, contrast in permeability and stiffness at the contact between the clay and underlying till), geomorphological processes (gradual erosion of the slope toe or rapid drawdown at meander locations), physical processes (snow melt and prolonged precipitation), and human activities (fill or cut construction on existing landslide blocks).

This presentation provides an overview of the geology, stratigraphy and groundwater conditions, current slope stability conditions, and the effect of rainfall to landslide activities in Southern Saskatchewan. The presentation also presents a number of case histories where potential significant economic loss of infrastructure and/or public safety concerns are involved.