Ottawa’s Secret Sand Dunes


Over 10,000 years ago a body of water covered the City Of Ottawa called The Champlain Sea, a deep sideline of the Atlantic Ocean. It occupied a depression created by a continental glacier, and then it drained away as the giant glacier that once covered the northern hemisphere disappeared and the earth rebounded back into shape.  Now its only remnants are the Ottawa and St. Lawrence Rivers. However, sand dunes were left to remind us of its former existence, sand dunes that exist hidden in the forests south of Ottawa off Slack Road. These dunes were a result of wind and water carrying sand left by the massive glacier into the sea by glacial rivers that once cut through through the glacial deposits. These sand dunes exist today, but are disappearing fast.


Once humans began to traverse these ancient sand dunes, evidence has appeared that native people who needed wood and game inhabited the region, and archeological artifacts have been found in the area.  Hidden behind a facade of forest trees, the “sand zone” is recognized for its archaeological potential. I recently visited the site and found it to be a unique area worth visiting if you have the chance.


This 1925 aerial view shows the once mighty extent of Ottawa’s Dune Sea. (photo from The Canadian Field Naturalist Journal June 2008)

Parking on a side road off Slack Road, we traversed up a small embankment to discover a flat plain of fine sand and dunes, stretching into the forest to the south. At one time this sand dune plain was massive, as a 1925 aerial photograph shows. In its current state it is just a fraction of its former self. The once mighty Dune Sea of Slack Road of about 3km in length has now been reduced to a few small areas of sand as the encroaching forest consumes this ancient Dune Region.


Comparison photos showing the disappearing sand dune region south of Ottawa. (from Canadian Field Naturalists Journal June 2008)

The area is now part of the Pinhey Forest Reserve (National Capital Commission) and contains numerous trails where one can explore this ancient sand dune area. Housing developments, an industrial park and re-forestation efforts have all but concealed the former dunes, but the ground beneath is definitely a sandy experience. There seems to be remnants of some kind of archeological dig at the various dunes, with sifting equipment strewn about.


The original sand dunes are now covered in forest growth, equally as magical. (photo Alison Fowler)

The forest that now covers the area is itself a unique feature as there are bizarre stick huts, carved stump monks and other oddities that give this hidden wonder a peculiar experience. Stick to the trails if you do go, and follow the trail maps, as it is very easy to become lost in the labyrinth among the secret sand dunes.

Andrew King, October 2016





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