Lake St. Peter is too shallow: how a section of the St. Lawrence has rendered Montreal's port obsolete

   Lake St. Peter just upriver from Sorel, appeared 12,500 years ago when a glacier melted, leaving a massive watery gap 32 km long by 14 km wide.

   The problem? The glacier was too thin.  As a result, the lake bed measures less than 35 feet under the surface. 

   Modern container ships need 55 feet of depth to navigate an aquatic route. 

   So thanks to Lake St. Peter the river that has long served as Montreal's moneymaker is 20-feet too shallow to be useful. 

   Today's container ships dwarf the ships that came into Montreal during its thriving era. 

   The Manchester Challenge was the first container ship in Montreal in the 1960s. It had a 500 TEU (twenty-foot equivalent unit) which meant it could haul 500 containers. 

   The average container ship nowadays is 20-times that size, at 10,000 TEU. 

   In 2008 the largest container ship was a massive 14,000 TEU but even that has been outstripped by 23,000 TEU ships.

   Fully-laden, these ships simply cannot make it to Montreal due to the shallow Lake St. Peter. 

 

World's largest containership has a TEU of almost 24k TEU

The Panama Canal, in recent years, has been widened to allow the larger ships, further pushing Montreal's port into irrelevance. 

   So this raises the obvious question which has been asked for about 60-years: 

   Lake St. Peter has already been dredged to reach 35 feet but the problem is that the more you dredge, the more water flows upriver from the Great Lakes, so the water level doesn't rise much with dredging.

   One would need a complex and costly engineering solution, which would likely not make much economic sense.

   Quebec City had a larger population than Montreal before Montreal built a better port in the 1800s.

   Quebec and other ports east are now getting their revenge.

    Christy McCormick, a veteran Hong Kong-based journalist who spent many years reporting on Montreal's waterfront trade, notes that not all is disaster for Montreal, which has nonetheless seen its tonnage rise significantly through the years.  "Montreal," he notes,"still prospers as the most convenient access to one of the richest consumer markets - the Quebec-Windsor corridor - on the planet."