A Canadian Heritage River


Canadian Heritage Rivers are recognized for their outstanding contributions to the country’s cultural heritage, natural heritage, and recreational opportunities. Over the last four years, volunteers have worked with the community to document and publicize the significant features of the Thames watershed. This information formed the basis of the river’s nomination in 1999. The Lower Thames Valley Conservation Authority and Upper Thames River Conservation Authority have been working with a large group of volunteers representing local citizens, experts, historians, professors, and recreationists over the last four years on a project to see the Thames designated a Canadian Heritage River. The Thames has joined an elite group of the most historic and beautiful rivers in Canada. The designation of the Thames River as a Canadian Heritage River, brings recognition, status and an opportunity to leverage local and provincial support for the river’s benefit.


In December 1998, the Thames River was officially nominated as a Canadian Heritage River. 1999 was a pivotal year in the project. In February, a media event was hosted in London to officially announce the nomination of the river and to thank the many volunteers and funders. In December, the final document in the process was submitted to the Canadian Heritage Rivers Board. The final step leading to designation was the writing of a strategy for the river’s future.

The Thames Strategy outlines how the watershed’s natural, cultural and recreational features and values will be conserved and interpreted for the future. The strategy provides an opportunity for river managers, stakeholders and residents to work together to continue to conserve and revitalize the river’s many values. Copies of The Thames Strategy are available from the Conservation Authority. This colourful report has been distributed widely to stakeholders in the watershed to springboard the next phase of the project.

On August 14, 2000, the Thames River was formally designated a Canadian Heritage River! The designation was announced by the Minister of Canadian Heritage, the Honourable Sheila Copps and Ontario’s Minister of Natural Resources, the Honourable John Snobelen.

The Unique Physical Features of the Lower Thames River

The Thames is a "gateway" watershed; it is located in the southern most part of Canada, directly linked to the Great Lakes and thus the Atlantic Ocean. The Thames is the largest river tributary to Lake St. Clair and the second largest river in southwestern Ontario. The lower Thames River flows parallel to Lake Erie toward Lake St. Clair passing through Delaware, Wardsville, Thamesville and Chatham as well as the Chippewa, Oneida, Munsee-Delaware and Moravian First Nation Communities. The Thames finally joins Lake St. Clair at Lighthouse Cove. Major lower Thames River tributaries include the Indian/McGregor Creek and Jeanettes Creek at around 30 km each. The Thames was one of the first rivers formed following the retreat of the last glacier in Ontario. The lower river flows through flat plains of clay and sand, the result of thousands of years under glacial lakes.

Because of the flat gradient in the lower Thames River, Lake St. Clair water levels often dictate water levels in the Thames, especially during low flows. High lake levels can actually generate a reverse flow upriver. The lower Thames, occupies a small valley of its own making. Below the forks in London, to Chatham-Kent line, depth is generally less than 23 metres. Further downstream, the river is generally not confined by its flat valley. The river is so shallowly entrenched below the old lake plain downstream of Chatham, that dykes have been constructed to control flooding of the adjacent lands. The level of the river is actually higher than the surrounding land at the mouth. The St. Clair National Wildlife Area is an internationally renowned marsh located along Lake St. Clair near the mouth of the Thames.

Much of the soil in the Thames River basin is well suited to agriculture, especially with tile drainage and, as a result, the area has been intensively farmed for over 200 years. Erosion rates along the stretch of river from Delaware to the Chatham-Kent line are not steady and there may not be any change in a bank for many years until a single large discharge passes through and scours the bank with enormous energy. Gullies are quite evident especially through the Munsee/Delaware First Nation. Here, the tributary streams cut through the sandy soil down to the base level of the river, creating steep-sided narrow gulches along their lower courses. Over time this area becomes raised. In the "Chatham Flats" area, this alluvium has a reddish cast that contrasts with the grey clay of the surrounding landscape which originated under glacial Lake Whittlesey.

The Carolinian Life Zone

There is a long growing season in the "deep south" of Canada. The Thames is the only major river in Canada with the majority of its watershed (over 90%) within the Carolinian Zone. About 22-24% of the Carolinian Zone lies within the Thames Watershed. It is called "Carolinian" because many of the plants and animals found here are also found in the Carolinas as well as the Ohio Valley. Trees that are common in the Carolinian Floristic Zone include Sugar Maple, American Beech, Red Oak, Basswood. There are also many less common species such as Black Walnut, Butternut, Sassafras, Sycamore, Hackberry, Tulip Tree and Black Oak which survive here because of the long growing season. More than 40% of Canada’s endangered species occur here, along with more than 25% of the country’s population. The natural areas along the Thames River play a significant role in preserving this province’s and country’s rare plant life. This region is widely recognized as one of the most biologically significant and diverse regions in Canada with more than 2200 species of vascular plants. The only Canadian site for the endangered Wood Poppy is in the floodplain of the Thames River.

Before human settlement, there were also extensive areas of tallgrass prairie, especially in Essex and Kent Counties. These were some of the first lands to be cleared for agriculture and, as a result, they are some of the most endangered communities in North America. Today, small pockets of tallgrass prairie are found along the Thames River banks and within its valley in suitable habitat.

The fauna is also extremely diverse in the watershed. The Thames contains the largest number of Eastern Spiny Softshell Turtles in Canada and is critical to the survival of this endangered species. Owing to its many habitats, nutrient rich waters, long growing season, and connection with the Great Lakes, the Thames River sustains one of the most diverse fish and freshwater mussel communities in Canada. The Thames River sustains one of the most diverse fish communities in Canada. The river’s complex system of interconnected springs, swales, ravines, streams and rivers provides a broad range of habitats for some 88 fish species from 19 families. The Carolinian influence is also reflected in the mammal community of the Thames. For example, the Southern Flying Squirrel, Virginia Opossum and Woodland Vole are all Carolinian Species at the northern edge of their ranges in Ontario. Many species, especially those with southern distributions, are at risk in Canada due to their limited range or because of habitat loss.


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