Saskatoon River Valley Geohazards – An Update and Modelling

ABSTRACT: The City of Saskatoon has had a long, but relatively unknown history of geohazards throughout the city limits owing to highly variable surficial geology and a moderately incised river valley. Landsliding activity ranges from large, retrogressive slides, translational to conventional circular slides as well as instabilities related to internal erosion. The complex glacial history of the soils in Saskatoon plays a key role in the type and nature of the instabilities. The presence of elevated groundwater levels within the uppermost surficial stratified drift and the relative location of the till layer and the river level are typically controlling factors. Other factors like possible artesian pressures within the lowermost Empress Sand and river levels that are reflective of the flow through the Gardiner Dam also play a lesser role. This paper will provide a brief synopsis of the surficial geology of the City of Saskatoon as well as a history of landslide activity on the east bank of the South Saskatchewan River. The landslide summary is an update to a previous publication that documented and described previous slide activity within the Saskatoon city limits. Lastly, a brief discussion on the current methods of slide remediation is discussed.