Carillon is the first hydroelectric power plant in the province to have been built under the supervision of French-Canadian engineers at the very beginning of the Révolution tranquille. The facility, located on the Ottawa River, crosses the Quebec and Ontario border. Located entirely in Quebec, the run-of-river power plant is equipped with 14 turbine-generator units representing an installed capacity of over 750 MW. The spillway, meanwhile, is located in Ontario and has a discharge capacity of over 11,000 m³/s spread over 12 passes.
 
The particularity of the site is that significant erosion of the rock mass in the immediate downstream reach of the structure has occurred since it was commissioned. In addition, this erosion process is still active and could daylight potentially critical geological structures for the stability of the structure.
 
Assessing the stability of aging gravity dams and spillways has been an important engineering challenge for the past few decades. Usually, concrete dam-rock interfaces are considered as potential weakness planes where failure may occur. However, other planes of weakness may exist within the foundation rock mass. These planes are potentially problematic only when a combination of adverse conditions is encountered. These conditions are, among others, the nature and continuity of the critical geological structures as well as the spatial relationship between their geometry and the topography of the bedrock downstream of the structures. In order to assess the potential of failure in the rock foundation of a retaining structure, it is preferable to apply the concepts and methods developed in rock mechanics.