Written by Lesley Peterson, Director of Conservation
Figure 1: Millpond Dam facing Upstream (November 2023)
Like many communities in Ontario, the town of Lucknow owes part of its history to the establishment of a mill pond. The Mill Pond Dam in Lucknow, ON was first built in 1856 to support an adjacent wool mill and powered other businesses as ownership changed hands over the years. It has been many years since the Mill Pond dam in Lucknow has been used for power generation. And, like other small dams, the Lucknow Mill Pond dam is now at or near the end of its lifespan. The pond has filled with sediment and the concrete spillway has started to erode and crumble.
The dam is owned by Morten Jakobson, who runs his business Protekta on the adjacent property. After a chunk of concrete on the west wall of the spillway broke off and fell inward in 2012, Morten began exploring opportunities to have the dam repaired but because the foundation of the dam was in such poor condition, this was deemed not viable. Morten then reached out to the Maitland Valley Conservation Authority for advice who suggested contacting Trout Unlimited Canada as we have experience with small dam removal and stream rehabilitation.
Ecological Issues
Figure 2: 2023 Water Temperatures from Above and Below the Mill Pond
TUC became interested in the project for the opportunity to restore water quality, aquatic habitat, and natural stream processes. Fisheries sampling was conducted and stream temperature monitoring was carried out to assess the current conditions. The sampling revealed that water flows coming out of the pond were generally warmer than water coming into the pond. This is not surprising considering the pond is wide and shallow and since it takes time for water to flow through the pond, there is ample opportunity for the sun to warm the water, especially during the hot summer months. This is particularly concerning for fish and aquatic animals that are sensitive to temperature, like Brook Trout. During fisheries sampling, TUC’s crews found Brook Trout heavily reliant on small pockets of habitat where groundwater comes into Dickies Creek. Not only is the temperate an issue in and of itself, but warmer water contains less dissolved oxygen which is critical to the survival of fish, aquatic invertebrates, and amphibians. Brook Trout can be seen as “canaries in the coal mine” – because they are sensitive to environmental change, they act as indicators of ecosystem health.
Supporters
Since becoming involved in the project, TUC has received grant funding from the Ontario government’s Great Lakes Local Action Fund and from Bass Pro and Cabela’s Outdoor Fund to support the project. Funds have been used to hire Palmer, part of SLR, to develop conceptual designs for dam decommissioning. Funding is also being used to support project management and community information sharing. Additional funds will need to be secured for dam decommissioning and associated stream rehabilitation.
Engineering and Design
In late 2023 Palmer surveyed the site to collect bathymetry data, sediment samples and measurements, and stream profile data that is being used to inform design options. As of February 2024, design is ongoing.
Community Engagement
In May 2023, TUC and Morten held a “come and go” community meeting at Protekta during which community members had an opportunity to see the dam, meet TUC’s professional staff, and hear about some of the ecological, safety, and liability concerns with the dam and pond. During the meeting community members also shared their concerns about the fate of the dam and pond.
A second community information session was held in January 2024 at the Lucknow Community Centre. At the meeting TUC staff provided background information on the project and shared case studies of other dam removal and stream rehabilitation projects that TUC has led and been involved with. The lead engineer from Palmer working on the project presented their work to date and two high level design options being considered.
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Next Steps and Decision Making
Conceptual engineering designs will be completed in the coming weeks and another community meeting is planned for early spring 2024 to share project updates and designs. Designs will also allow TUC to move forward with regulatory permit applications.
It is unknown how long the dam will last. A major storm or rainfall event could pose significant risk to the integrity of the structure. A dam failure would put residential homes, businesses, and infrastructure at risk. Significant environmental damage from uncontrolled sediment release, flooding, and erosion could also occur if the dam failed. Ultimately, all liability and decision making associated with the dam rests with the landowner. TUC will continue to explore funding opportunities to support dam removal to meet shared goals of reducing safety, environmental, and liability risks.
Disclaimer: This project has received funding support from the Government of Ontario. Such support does not indicate endorsement by the Government of Ontario of the contents of this material.
To read TUC’s policy on small dam removal, CLICK HERE.
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