Locks along the Saint Lawrence Seaway (the Seaway) are usually closed from 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, such as vessel incidents and weather.
Excluding the winter closure, the 2004 season for the two locks in the Seaway maintained and operated by the United States consisted of 281 days. The U.S. locks, located between Montreal and Lake Ontario, had 66 hours (almost 3 days) of downtime during the 2004 season. Weather-related poor visibility, high winds, and ice caused 66 percent of all lock downtime; vessel incidents caused another 23 percent .
Weather or vessel incidents caused most of the lock downtime between 1994 and 2004. In all but three years (1997 through 1999), over 50 percent of lock downtime was because of weather (figure 12-6). Weather and vessels each caused 43 hours of downtime in 1998, and vessels caused 46 hours of downtime in 1999. 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].
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 (figure 12-7). During the 2004 navigation season, 30.5 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 constituted the majority of shipments .
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/, as of July 2004.
2. ______. Fiscal Year 2001 Annual Report: Linking North America's Heartland to the World, available at http://www.greatlakes-seaway.com/, as of July 2004.
3. ______. personal communication, February 2005.
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.