Phénomènes d’érosion fluviale et conditions hydrodynamiques de la rivière Saint-Maurice, Québec, Canada

Abstract

This study was made in the lower portion of the Saint-Maurice River, one of the important rivers of Southern Québec. This study examines processes and phenomena who affect several banks of this portion of the river. Factors responsible for bank erosion such as waves and currents, water level changes and ice conditions are examined. The study covers specifically the river section between the Manigance rapids, North of the Grand-Mère hydroelectric power plant, and the des Hêtres rapids, in the South. Upstream of the power plant, banks are mostly made of clay or silty-clay more than half of the banks are active, that is 74,7 km on a total of 114,4 km. Downstream of the power plant, banks are mostly made of sand or a mixture of sand and gravel. The active banks form less than 10 %, or about 10,5 km in length for this sector. The rate of bank recession assessed by the digitalization of aerial photographs is of about 0,5 metres per year for the most eroded banks. The most affected zones are located in the high terraces of clay.

Keywords

• bank erosion and bank recession
• calculation of waves erosion
• hydroelectric power plant
• Saint-Maurice River
• Québec
• Canada