Locks along the Saint Lawrence Seaway (the Seaway) are usually closed between late December to late March because of ice. At other times of the year, shipping can be disrupted when locks are closed for other reasons.
Excluding the winter closure, the 2002 season for the two locks in the Seaway maintained and operated by the United States consisted of 276 days. The U.S. locks, located between Montreal and Lake Ontario, had 63 hours (just over 2½ days) of downtime during the 2002 season. Weather-related poor visibility, high winds, and ice caused 65 percent of all lock downtime; vessel incidents caused another 27 percent. Lock malfunctions caused only three hours of downtime during the 2002 season, 5 percent of the total.
Over the last decade, weather has been the primary cause of downtime (figure 8-8). Exceptions include 124½ hours of downtime in 1993 caused by water level/flow and 43 and 46 hours in 1998 and 1999, respectively, caused by vessel incidents. Although weather was responsible for the majority of downtime hours in 2001, vessel incidents that year accounted for 45 hours of downtime.
Lock downtime is not the only way Seaway shipping is impacted. For instance, in 2000 and 2001, water levels in the Great Lakes were at their lowest point in 35 years. During these reduced water level periods, some vessels could only carry approximately 90 percent of their normal shipment loads [1, 2].
During the 2002 navigation season, 30.0 million metric tons of cargo were transported through the Montreal-Lake Ontario section of the Seaway. Grain, iron ore, and other bulk commodities, as well as manufactured iron and steel, constitute the majority of shipments .
The Seaway is part of the Great Lakes Saint Lawrence Seaway System jointly operated by the United States and Canada.1 The entire system encompasses the Saint Lawrence River, the five Great Lakes, and the waterways connecting the Great Lakes, and extends 2,340 miles—from the Gulf of the Saint Lawrence at the Atlantic Ocean in the east to Lake Superior in the west.
1. U.S. Department of Transportation, Saint Lawrence Seaway Development Corp., Fiscal Year 2000 Annual Report: Great Lakes Seaway System Moves Forward Into the 21st Century, available at http://www.greatlakes-seaway.com/en/pdf/fy2000ar.pdf, as of July 2004.
2. U.S. Department of Transportation, Saint Lawrence Seaway Development Corp., Fiscal Year 2001 Annual Report: Linking North America's Heartland to the World, available at http://www.greatlakes-seaway.com/en/pdf/fy2001ar.pdf, as of July 2004.
3. ______. Fiscal Year 2002 Annual Report: Linking North America’s Heartland to the World, available at http://www.greatlakes-seaway.com/en/pdf/fy2002ar.pdf, as of July 2004.
1 The U.S. Saint Lawrence Seaway Development Corp. operates and maintains the U.S. portion of the Saint Lawrence Seaway between the Port of Montreal and Lake Erie.