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Trent Severn Waterway – Mississagua Dam Update, April 2017

April 19, 2017 – During the week of April 3, 2017 the new Mississagua Lake dam began to take shape with the creation of the first two concrete piers.   These piers built upon the concrete pad that had been previously poured as the foundation of the new dam.

Additionally, the wingwall connecting the shoreline to the easternmost pier has been formed up, and rebar set, in preparation for pouring the concrete that will form that portion of the new dam.  This pouring is anticipated in the coming days weather permitting.

The final piece in this first phase constructing the eastern portion of the new dam will be the forming and pouring of a rollway between the two piers.  A rollway is a contoured concrete surface at the base of the spillway that incorporates a sill plate.  The logs controlling the flow of water through the dam will seat on this sill plate.

Once the rollway is complete, work will begin transitioning to the next phase of this project.  Part of the existing temporary coffer dam will be removed to enable water to be shifted back to the easterly side of the site.  The remaining coffer dam will then be extended to facilitate the creation of piers on the westerly side of the site.  This shift to the second phase is currently anticipated to take place by May.

Water levels will continue to be carefully monitored and Parks Canada’s team members stand ready to make adjustments as required.
The replacement of the Mississagua Lake Dam is part of Parks Canada’s unprecedented $3 billion dollar investment over 5 years to support infrastructure work to heritage, visitor, waterway and highway assets located within national historic sites, national parks, and national marine conservation areas across Canada. These historic investments will mitigate health and safety risks, halt the loss of nationally significant built heritage and stimulate the economy in communities across the country.

Construction Site Safety

The replacement of the Mississagua Lake dam is a historic event and there has been tremendous interest amongst residents and visitors to the area.  There have been many reports of unauthorized individuals accessing the site to take a look at how work is progressing.  Unauthorized access to the construction site is strictly prohibited and can result in fines, serious injuries, or worse.  Parks Canada will continue to provide regular updates and photos about the progress of this project.  We respectfully ask that all posted signage be respected throughout this important project.

About Mississagua Lake Dam

The current dam at Mississagua Lake dates to approximately 1930 and replaced a timber crib dam that had been previously built in the area.  Remnants of this timber crib dam can still be seen in the water upstream of the dam site.  While numerous repairs have been made on the dam over the years, there have not been any major rehabilitations since the original construction.  When the existing dam was built it was anticipated that the water level of Mississagua Lake would be set much higher, thus explaining the abnormal difference in height between the dam and the overflow weir.

For More Information:

For up-to-date news on infrastructure work along the Trent Severn Waterway, please visit our website: If you have questions about the project to replace the Mississagua Lake Dam or if you would like to be added to our community engagement list and receive updates on this project, please contact us at: and include Mississagua Lake Dam in the subject heading.