Table 2 



Low Water (chart) Datum for IGLD 1955 and IGLD 1985 



Low Water Datum in Meters 



Location 



IGLD 55 



IGLD 85 



Lake Superior 



182.9 



183.2 



Lake Michigan 



175.8 



176.0 



Lake Huron 



175.8 



176.0 



Lake St. Clair 



174.2 



174.4 



Lake Erie 



173.3 



173.5 



Lake Ontario 



74.0 



74.2 



Lake St. Lawrence at Long Sault Dam, Ontario 



72.4 



72.5 



Lake St. Francis at Summerstown, Ontario 



46.1 



46.2 



Lake St. Louis at Pointe Claire, Quebec 



20.3 



20.4 



Montreal Harbour at Jetty Number 1 



5.5 



5.6 



Lake St. Lawrence (72.5) 

 at Long Sault Dam. Ontario 



Lake St. Francis (46.2) 

 at Summerstown. Ontario 



Lake St. Louis (20.4) 

 at Pointe Claire, Quebec 



Montreal Harbour (5.6) 

 at Jetty Number 1 



Distance (Km.) 



Figure 12. The reference zero point for IGLD 1985 at Rimouski, Quebec is shown in its 



vertical and horizontal relationship to the Great Lakes-St. Lawrence River 

 System. Low- water datums for the lakes are shown in meters 



Chapter 2 Secondary Sources of Coastal Information 



21 



