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Health of the Rideau River


A Century Ago: "Deplorable" Pollution

Swamp milkweed, Asclepias incarnata.
Swamp milkweed, Asclepias incarnata.

While the health of the Rideau River is frail in some areas, it is much better than it was a century ago. At the start of the 1900s, fish populations were decimated and water pollution was deplorable!

Intensive Fishing and Trapping
It is only possible to guess at the composition of the flora and fauna before the arrival of settlers in the Ottawa Valley, around 1800. In fact, records only go as far back as the end of the 19th century. These documents primarily concern native species that had commercial value.

Around the end of the 19th century, the harvest of mammals for their pelts and fish was intense, and animal populations were affected. In 1899, the state of the Rideau River fish community was so poor that the sale and export of all sport fish was prohibited for the next three years.

Water Pollution on the Rise
As the City of Ottawa grew the Rideau River became more polluted; residents discharged their wastes directly into the River. In 1918 a letter published in The Ottawa Citizen described the pollution in the Rideau River as "deplorable". [7]

Newspaper articles of the 1940s and 1950s detail extensive restocking of fish in the Rideau River, intended to improve the quality of sport fishing in the region. It was then believed that fish stocks were decreasing solely because of angling pressure. Deterioration of water quality was not considered.

During the 1960s and 1970s, rapid population growth and increased development along the Rideau River caused water pollution levels to rise. The improvement of transportation waterways through the Great Lakes enabled the invasion by European and Asian exotic species of the Lakes and the Rideau River. [6, 29]

Measuring a fish.
Measuring a fish during the Project.
The Tide is Turning
Happily, the tide began to turn during the next decades. During the 1980s and 1990s, urban populations stabilized. [29] Citizens and governments became more aware of the need to protect the environment, and infrastructures were built for that purpose. These changes resulted in an overall improvement of the water quality and health of the River.

Present-day studies such as the Rideau River Biodiversity Project establish a base from which trends may be monitored and changes may be closely followed.

Subtle Warning Signs
While the health of the River is relatively good, the Project has identified early signs of declining River health. The disappearance of native freshwater mussels from certain areas, the loss of adequate habitat for amphibians and reptiles, and the possible disappearance of a sensitive minnow species warn of a renewing decline that will continue if we're not careful.


 Health of the River  

The Rideau River, in Ottawa.
The Rideau River, in Ottawa: Cleaner than it's been in decades!
A Project of the Canadian Museum of Nature
 Images: Lynn Gillespie, Anne Phelps