Three (3) ice retention booms are deployed each year on the St. Lawrence River. These booms have been placed at strategic locations on the river in order to create an ice cover early in the winter season and hold it in place all winter. This way, the formation of new ice upstream is minimized. This prevents ice accumulation in the navigation channel, reducing the risk of ice jams and flooding. The three booms are located between Montreal and Trois-Rivières. A first boom is located upstream of Lavaltrie, near Île Mousseau; the second at Lanoraie, near Île Saint-Ours; and the third on the north shore of Lac Saint-Pierre, between artificial islet 4 and Pointe de Yamachiche. Figure 1 shows the location of the three booms.
At Lavaltrie, the boom consists of 8 sections of 11 steel beams. At Lanoraie, the boom consists of 11 sections of 11 steel beams. The Yamachiche boom consists of 20 sections of 11 steel beams. All the beams are connected with chains to steel cables 51 mm in diameter by 152 m in length. These boom sections are in turn connected by cable to anchors buried at the bottom of the St. Lawrence River. The anchors and their cables are left in place over the summer; a yellow plastic buoy (SB-40) marks the location of each anchor.
Each year, the ice booms are removed in spring and stored for the summer season. This procedure is required to maintain the structures and their components, as well as to ensure free passage of pleasure craft in these sectors during the summer. Maintenance of parts is usually done during the summer by Canadian Coast Guard personnel at the Sorel Base. In the fall of each year, the booms are redeployed between October 16 and November 17 at the latest.
These specifications describe the removal, transport and unloading of booms at Sorel in spring as well as retrieval from the Sorel Base, transport and installation of the booms in fall. It also describes anchor and anchor cable replacement.
