3D modeling of Lac Saint-Pierre's hydraulic behaviour in the presence of an ice cover and analysis of scenarios leading to a better evacuation of the ice in the navigation channel

Period of execution: December 1996 to July 1997

Customer's name: Fisheries and Oceans Canada, Canada Coast Guard section, in partnership with the National Research Council of Canada

Summary:

A 3D model with finite elements technology allowed us to simulate the lac Saint-Pierre's current mode in the presence of ice blocks of variable size. The study of scenarios, corresponding to different hydrological conditions, make it possible to evaluate the efficiency of the widening navigation channel on a small area (60m x 5 km) to support a better evacuation of ice and to prevent ice jam. A CNRC model with the discrete elements method uses the results of the hydrodynamic model to simulate the process of ice evacuation.

Principal activities carried out:

• Adaptation and validation of a 3D hydrodynamic model with finite elements technology which take into account the shear stresses connected to the presence of ice covers of irregular shape;
• Building of a meshing with irregular triangular elements which reproduces the shape of the channel with enough detail in order to study the impact of dredging on a small area of Lac Saint-Pierre;
• Analysis of the hydraulic conditions of lac Saint-Pierre in presence of various dimensional ice covers;
• Carrying out simulations corresponding to real hydraulic conditions;
• Validating the model's results with current measurements;
• Analysis of various scenarios in order to improve ice evacuation and prevent ice jam.
  

Reports, Presentations, Publications:

Gagnon, M. and B. Morse, 1996. Modélisation mathématique de l'influence des conditions hydrauliques réelles sur l'évacuation des glaces dans le lac Saint-Pierre. Coastal Zone Canada 96. Rimouski, august 1996.

Gagnon, M., 1996. Modélisation 3D du comportement hydraulique du lac Saint-Pierre en présence d'un couvert de glace et analyse de scénarios conduisant à une meilleure évacuation des glaces dans le chenal de navigation. Océanide Inc. Septembre 1996. 113pp.


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