| |
 |
|
 |
 |
 |
|
|
|
|
 |
Barely 15 000 years old, the St. Lawrence River is the world's youngest seaway!
When out in the middle of the river, you feel you are
at sea, and when close to shore, the physical traces
of this waterway's birth and evolution can be read on its rocky shoreline. The
St. Lawrence originates in the Great Lakes, but the waters from several other
rivers that flow into the seaway contribute to its powerful current. Learn about
the fascinating natural phenomena that create
the magic of the St. Lawrence River.
The St. Lawrence River originates from the Great Lakes. As it flows towards the
Atlantic, it increases in size due to the runoff from many streams and rivers
in Quebec. The river flows through a variety of landscapes: flatlands and marshes,
beaches and sand dunes, rocky shorelines and reefs, each with its own species
of plants and animals. Humans have founded cities and villages along the St. Lawrence
for millennia. Unfortunately, humans and beautiful natural environments do not
always make the best neighbours…
Shoals and reefs
Submerged dangers in the seaway
The waters of the St. Lawrence froth and churn as they pass over the
Lachine Rapids near Montreal. Later on, the slope of the St. Lawrence's
riverbed evens out, and the river flows smoothly almost all the way
to Quebec City in a rounded valley. Vessels travel through a channel
dug into the riverbed. However, the riverbed becomes broken once again
near Quebec City, making sailing hazardous starting at the point where
the St. Lawrence reaches the mountains of the Laurentian Shield on
the North Shore and the Appalachians on the South Shore. Navigating
between Quebec City and Tadoussac requires excellent knowledge of
the river.
Shoals (underwater ridges) in the St. Lawrence
The riverbed of the St. Lawrence is irregular. The depth of the water
can suddenly vary by several metres due to shoals and bars. These
natural obstacles sometimes lie just beneath the surface of the water.
Near Bic, a short distance from Rimouski, an entire mountain is hidden
beneath the waves!
Shoals of all sizes are sources of concern to sailors. Colliding with
a shoal can damage a hull, cause a boat to capsize or even split in
two! If the ship has run aground on a shoal, there is a small chance
it may be able to float free with the rising tide. The only other
alternatives are to have the boat towed or abandon it to pirates!
Navigational hazard near Tadoussac: Prince Shoal
One of the most dangerous shoals in the St. Lawrence River is found
near Tadoussac. A lighthouse that resembles a child's top because
of its tapered base warns passing vessels of the undersea hazard in
the area. Yet despite the presence of this lighthouse and modern navigation
equipment, a passenger liner sank here a few years ago after striking
Prince Shoal in the middle of a sunny summer afternoon! The only consolation
to the ship's captain was that his ship was not the first to have
suffered this fate…
Reef surrounding Anticosti Island
Anticosti Island is the largest island in the St. Lawrence River,
but also the most difficult to approach by boat. It is surrounded
by a solid barrier reef that has been the site of many shipwrecks.
Sailors kept a watchful eye when passing near Anticosti Island, as
a powerful gale could break an anchor line and cast a ship on the
rocks, sealing its fate! |
|
|
|
 |
 |
|
