Oxbow And Other Dunes Of Wasaga

This piece follows The Story Behind The Beach: A Grain Of Sand published on August 5th

Wasaga Beach is known primarily for the beachfront, but there are other areas away from the beach that are hidden gems. As you paddle the Nottawasaga River through a bend not far from its mouth, you will encounter a large parabolic dune formation, called the Oxbow. Geologically, Oxbows are lakes when a meandering river with many curves erodes through the neck of one of its meanders and follows a shorter course that bypasses the meander. The entrances to the abandoned meander eventually silt up, forming an oxbow lake. Because oxbow lakes are still water lakes, with no current flowing through them, the entire lake gradually silts up, becoming a bog or swamp and then evaporating completely. There are countless examples of this process in the world.

The Nottawasaga River Oxbow is not such a geological feature as it is not a lake, and is therefore not appropriately named.  There are four major types of dunes: barchan, parabolic, star and longitudinal. The Oxbow of Wasaga Beach is in fact a parabolic dune which by some is also called U-shaped, blowout or hairpin. It is a mature dune, no longer subject to blowouts because of the growth supporting it, and the surrounding protecting woodlands.

You can hike in to the top of the dune but the best view is from the Nottawasaga. While walking and stopping for views or photographs you can reflect on how the dunes are an important part of Wasaga Beach’s geological history. Caution is advised when walking along the top of the dune. Not unlike snow avalanches, land slides can occur on dunes, such as the one at the Oxbow in April 2016, in which a large section of the dune collapsed into the river.

Oxbow Dune After Landslide

Oxbow Sand Slide – April 2016

On August 15, 1994, four young boys playing at the foot of the 10-meter high dunes in Sand Hills Park on Lake Erie, when about 10 tons of sand collapsed on top of them. Up to 30 people were digging for them, but none of the boys survived. I shudder to think of the time when my three children were playing at the foot of the same dune on one of our several trips there only a few years before, unaware of the danger!

There were no signs posted there at that time warning the many hundreds of visitors to the dunes. Nowadays there probably are, because 400,000 people visit the park’s beaches and dunes each year.

Similar dune slides and deaths are recorded from many other places around the world.

The ecology of sand dunes consists of their characteristic natural biological diversity, their physical and their human interactions which are part of their creation, existence and disappearance.  Where that balance is not upset by human actions, we are presented with natural examples of incredible biological diversity, consisting of areas situated right next to unstable beaches as well as largely undisturbed inland areas.

Many sand dunes are now protected as nature reserves, some as parts of larger conserved areas incorporating other coastal habitats such as mud flats, salt or sweet water marshes, mud flats, grasslands, scrub and woodland.

How then are dunes created? To the average uninitiated viewer they are simply a bunch of sand piled up to use for their recreational activities, be it for just peaceful sunbathing or, for others, for use with their wheeled motorized vehicles, from motorbikes to “all terrain” vehicles and even sand boarding and sand skiing.  Little do they realize or even care that they are transgressing into a range of unusual, interesting and unusual plants which can only exist in undisturbed habitats.

Naturalists have a significantly different view of how sand dunes are formed.

Anyone who has ever walked a beach on a windy day will have noticed that sand grains seldom travel far above the ground. The unpleasant stinging feeling on naked feet and other bare body parts illustrates the incredible power of their flight.

All dunes start as small sand droppings known as “embryo dunes” around obstacles such as plants or driftwood. While growing, these attract small plants to take root, helping to stabilize the sand.

As the wind reduces its speed on the lee-ward side of a dune, it drops most of the sand carried from the windward side, which eventually, through rain, snow and other weather influences, links with the soil and the prevailing humus on that side, where it joins the plant communities already in existence there.

Only a trained Naturalist can recognize the characteristic range of plants on the dunes which can survive the continuous blasting of sand grains, or being buried again and again by sand while trying to keep their living space from being blown away. One of the ways they accomplish this is by growing underground rhizomes to link with each other.

The ultimate stage in the development of dunes is woodland. At the Oxbow Dune in Wasaga Beach practically all stages can be seen within less than 300 feet of each other. In fact, there is a very old overgrown dune in the forests of Wasaga Beach which is visible in aerial photos. I have been told that it is even visible from satellites, but I still have to go there; it’s a long walk on a somewhat rough woodland trail.

Sand dunes in one stage or another of their developments are present along the entire east coast of the South Georgian Bay. In many cases however they have been damaged or obliterated by roads along the beaches. In the Wasaga Beach Provincial Park and the Bluewater Beach Ecological Park, they can still be found.


Written by

Peter Iden is a resident of Wasaga Beach and a Naturalist and Photographer who has a broad range of knowledge of the natural world. Peter is also a volunteer Warden for the Piping Plover Recovery Programme with the Friends of Nancy Island.

Email: cmis-cbc@rogers.com

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