Dam at Lock 37 Replacement
City of Kawartha Lakes
The Bolsover Dam at Lock 37 is a mass concrete gravity structure with a height of 12.3 m (maximum at the piers) and length of 68 m. The difference in water levels between upstream and downstream of the dam is approximately 6.7 m. The dam is located adjacent to Lock 37 on the Trent-Severn Waterway – a part of what is known as the historic Talbot section. The relatively unchanged appearance and operation of this section of man-made canal between Lake Simcoe and Balsam Lake is one of the reasons that the Trent-Severn Waterway is designated a National Historic Site.
Why did the dam need to be replaced?
The Bolsover Dam was originally constructed in 1902-1903 on a gravel and timber foundation. This foundation, while a common and acceptable manner of construction at the time, does not meet today’s design standards. After more than 100 years, this foundation had begun to show signs of deterioration.
What does it take to build a new dam?
In instances where an original structure can’t be saved and must be re-built, Parks Canada, including many skilled engineers, cultural resource specialists, and operational team, consider many factors before making a design decision. These include the effective use of funds, the impact on the natural environment, the ability of the structure to adhere to current codes of safety and operation, and an array of other Federal, Provincial, and Parks Canada policies. Of particular importance and unique to Parks Canada, are the decisions taken in an effort to maintain the look of the landscape, while also using modern construction techniques to improve the structure and ensure its longevity for future generations.
Public safety is a priority for Parks Canada. Our directive for infrastructure provides guidance on dam safety and follows safety guidelines developed by the Canadian Dam Association. Due to the magnitude and cost of this project there was a complex array of preparatory work undertaken, including: a rigorous environmental assessment, cultural resource assessments, consultations with Natural Resources Canada, and extensive surveying of the land and watercourse. Additionally, Parks Canada obtained permission under the Navigable Waters Protection Act (NWPA) to make changes to the navigable approach at Lock 37 Bolsover.
The construction phase included: removal of the existing dam, construction of a new dam in the same location, and all associated works to facilitate the construction including the installation and removal of two cofferdams one above and below the dam. This work also involved establishing a flow diversion system, the salvage of historical operational features, and de-mobilization including removal of the cofferdams, flow diversion system and all associated temporary ancillary works that facilitate the construction effort.
Parks Canada has a responsibility to protect nationally significant examples of Canada’s natural and cultural heritage. Often, these examples are in the form of structures like buildings, locks, and dams. In some places, like on Canada’s historic canals, these structures are still being used today, serving today’s needs. This presents challenges, like retaining the look and feel of a structure or landscape, and ensuring its continued use while accommodating 100-200 years of human growth. However, this animation and daily use allows Canadians to experience our treasured places in a unique and rich way.