Three Rock Rapids

Three Rock Rapids

The first full day of spring 2021 in Ottawa didn’t disappoint. Clear blue skies and warm temperatures brought people out in droves from their winter hibernation and eternal lockdowns. It was just what people needed to break out of their year-long COVID funk. I spent the afternoon with my son, Nick, at Hog’s Back Falls which, at this time of year, are rushing at full speed. Unlike the natural falls at the end of the Rideau River, where it empties into the Ottawa River, the Hog’s Back Falls are man-made. But no less spectacular.

The creation of the falls is tied to the construction of the Rideau Canal. In the pre-canal era, Hog’s Back Falls was known as Three Rock Rapids. The rapids only had a drop of 1.8 metres (6 feet), which was not nearly enough to flood the Rideau River to the depth necessary to put water over the upper sill of the locks at Hog’s Back, the entrance to the canal cut to the Ottawa locks. It was necessary to construct a dam which would raise the water level in this location by about 12.5 metres (41 feet).

Building a dam of this type at this location in the 1820s presented a number of construction challenges — it collapsed three times during construction, but was finally completed in 1831, allowing for the opening of the Rideau Canal.

The formerly gentle set of rapids just north of Mooney’s Bay is now a picturesque series of waterfalls, officially known as the Prince of Wales Falls. They are at their most spectacular in early spring when the canal is still closed and the full volume of the river rushes over the former Three Rock Rapids.

It is one of the highlights of spring in the nation’s capital, and remains one of Ottawa’s major tourist attractions at any time of year.