Introduction
The Birth of a River
The Big Chill
Of Steam and Stone
Raindrops to Rideau Falls
Raindrops Keep Falling
Getting the Drift

Our River the Rideau
Introduction

This story is about one of the great little rivers of the province, the magnificent Rideau River in Eastern Ontario. This river has given us everything- our history, our landscape, our familiar place names, our jobs, our businesses, our memories and probably our future. It has given and given without complaint for over 150 years of European settlement. People have come to take it for granted. The Rideau will always be here for us to use.

But lately, something’s going wrong. The warning signs are there. Beaches are closing, the water is green in places, the fishing is getting worse, and a quiet paddle can turn into a dizzy nightmare of buzzing boats. Times are changing. The river is changing. The three things everyone wants on the Rideau are the three things most at risk: clean water, wildlife and attractive stable shorelines. The lovely Rideau can no longer handle the pace of modern use and abuse we are giving her.The problem has been developing slowly, unnoticed from day to day and year to year. Suddenly, like wrinkles, you wake up one day and there they are! Fortunately, the things that have been creeping up on the Rideau can be fixed. It’s largely a matter of attitude.

We want to turn neglect into respect. What we do to our old friend the Rideau over the next few years is crucial. Sure, it has a few wrinkles, but for the most part the Rideau River has a lot going for it. Our Rideau is every bit as interesting and worth boasting about as the other great waterways of this province. And we can help it get even better.

Colonel John by began to put a series of locks and small dams on the free-flowing Rideau River for defence against the United States in 1826. Today, those same locks bring boaters along the beautiful recreational gem called the Rideau Waterway. But the Rideau is still very much a natural waterway- the plants, the animals, the floods, the watershed, Rideau Falls, the rocks -the ecology of the RIVER shines right through. A drop of rainwater that falls in Carnahan Lake in far-away Olden Township (now part of Central Frontenac), or the water meandering down the lazy Jock River in Richmond, or the water tumbling over the Oxford Mills Dam on Kemptville Creek - most of these waters will eventually flow past Mooneys Bay, on through Ottawa and over the Rideau Falls into the waiting Ottawa River.

This natural flowing system and complex natural valley is what this book is all about. The valley is the stage and the river is the star of the show.

A healthy river means a healthy valley, and a healthy valley means a better quality of life for everyone. After all ... it’s our valley.© Rideau Valley Conservation Authority.

^ up

The Birth of A River

It was a dark and stormy millenium when our part of the Earth’s molten crust bubbled, boiled over and started to cool. Those first hot rocks, the roots of ancient mountains, formed a mass of very old and very hard stone known as the Precambrian Shield. The hilly area west of present-day Smiths Falls is what’s left of those rugged ancient outcrops formed over three billion years ago.

East and north of Smiths Falls, the Precambrian rocks dip below the surface, forming a huge hardrock basin.

The forces of wind and rain eroded the mountains, and the area was slowly covered with layers of younger rocks like limestone and sandstone. These were laid down, one on top of the other, in broad flat plains in the bottom of the basin.

Finally, as recently as one million years ago, the surface was rearranged by massive cracking, heaving and erosion. To top it all off, as many as four glaciers ground their way back and forth across the face of Eastern Ontario. They made a heck of a mess. The last of these moving ice mountains melted away a mere 10 000 years ago.

^ up

The Big Chill

The weight of the glacier several hundred metres high depressed the land in the “Rideau Valley” to well below sea level. When the ice finally melted northward and exposed the St. Lawrence Valley, sea water rushed in and flooded the lowlands.
At its peak, this new branch of the Atlantic Ocean covered all land below the present elevation of about 120 metres. Now known as the Champlain Sea, it covered more than half of the Rideau Valley right up to present-day Smiths Falls, located on the edge of the basin.

The land rose slowly back into place after the ice melted. As the land rose, the Champlain Sea was gently tilted back down the St. Lawrence. Souvenirs of its existence includ the whale, seal and other marine skeletons found near Ottawa, far inland from the nearest body of salt-water today.

Where you are: Rideau Valley >Rideau Watershed > Our River, the Rideau > Excerpts

Of Steam and Stone

The first major man-made event in the history of the Rideau occurred from 1826 to 1832. Colonel John by and the Royal Engineers created the Rideau Canal, one of the world’s most daring and inspiring civil engineering triumphs of the times.

Colonel By designed a remarkable waterway that took full advantage of the Rideau River’s natural unique features. The plan was based on the river’s high stable banks and the abandoned river channels, called “snies”, parallel to the present riverbed. His innovative idea was to flood out obstructions and rapids by building dams, and then pass the canal around the dams by a series of locks.

With this system, By joined two natural rivers, the Rideau and the Cataraqui, into one navigable 200-kilometre waterway from Ottawa to Kingston. The artificial channel cut through at Newboro joins the north-flowing Rideau to the south-flowing Cataraqui.

What effect did this massive construction job have on the Rideau? Water levels were raised all along its length. Low islands and peninsulas were lost underwater. Wetlands and low-lying shoreline were flooded out. New wetlands were created. Rapids, falls and the natural flow of the river were drowned out as dams slowed down the current and made deeper, longer stretches between locks.

Today, the Rideau has recovered from the trauma of canal construction, and the military highway has turned into a world-famous tourist route. The natural beauty and elegant engineering of this waterway make the Rideau River perfect for tourism, nature study and recreation. For generations, the river has been essential to the folks who live along its shores. It has become a member of the family.

^ up

Raindrops to Rideau Falls

The Rideau Valley is roughly shaped like an isosceles triangle. One point is at Ottawa. Another point is about 10 kilometres north of Brockville on the St. Lawrence, and the last is near Mountain Grove on Highway 7 in the lovely County of Frontenac. The whole Rideau Valley covers an area of over 4 000 square kilometres, two-thirds the size of Prince Edward Island!


The deepest point in the waterway is in Big Rideau Lake, west of the Rocky Narrows where the plumb bob settles in at over 100 metres straight down. The north shore of the Rideau Lakes is one side of an ancient fault in the bedrock.

It’s about 130 kilometres from the headwaters of the Rideau waterway south of Sharbot Lake to its mouth at (former) Ottawa City Hall. At Rideau Falls, the river plunges 11 metres over a ledge of limestone in the beautiful “curtain” of water for which the river was named by early Canadian voyageurs. About four percent of the mighty Ottawa River’s volume comes from the Rideau.The three largest tributaries of the Rideau are:

1. the Jock River, which drains a subwatershed areas of 572 square kilometres south and west of the National Capital Region;
2. Kemptville Creek, with a subwatershed of 458 square kilometres starting down near the St. Lawrence River; and
3. the Tay River, which drains the 456 square kilometres Bobs Lake area west of Perth.