Sat. Mar 2nd, 2024
Staff and dip nets

Neys Provincial Park recently removed an obsolete dam as part of its work to restore and maintain ecological integrity. Superintendent Allison Dennis has the story…

The term “dam” piqued my curiosity after my first review of the Neys Provincial Park Management Plan.

It turns out that a dam is a barrier built across the width of a river or stream that raises the water level on the upstream side to a specific height. Unlike a dam, which redirects excess water through spillways, a dam allows excess water to flow over the top of the structure and continue downstream.

So what does this have to do with a provincial park?

It’s time to update the Neys water fountain

Original Neys Dam

Here in Neys Provincial Park, we have a concrete dam located on the creek that formally served as the park’s main water source. This concrete dam allowed the stream to accumulate water. This water was then used to supply the park’s original pump house.

In 2003, our new water treatment plant was built to meet updated drinking water standards. This new system provides a better water supply for the park and made the old dam obsolete.

The time had come to dismantle the dam.

Why remove the landfill?

Baby Brook Trout

Landfills, even small ones, can lead to habitat fragmentation. This means that the movement and migration of fish and other stream inhabitants may be restricted.

Cold water streams, like this one, contain habitat for fish and serve as important spawning and nursery grounds for salmonid species.

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Removing this dam was an important step in restoring ecological integrity in Neys. Removal improves stream and habitat connectivity and reduces potential sedimentation impacts. It can make access to the habitats and food sources that fish need to survive a challenge!

Weirs can also cause changes to the landscape upstream and downstream of a stream. Upstream of a dam, stream-like habitats begin to accumulate and become more lake-like. This can result in a loss of natural features (such as riffles) that are important spawning and nursery habitats.

Downstream, the spawning habitat (and diversity of that habitat) may also be affected through a reduction in the amount of gravel that can move freely downstream.

In general, man-made structures such as landfills can also affect stream temperatures, water velocity, oxygen content, and erosion. Together, these changes have the potential to stress a stream’s ecosystem and negatively impact stream biodiversity and fish populations.

It was clearly worth it to get that prey out of here!

How did we do it?

Dipping stick and nets

The removal project began with fishery monitoring work to determine what species were present and support the environmental assessment process.

Since removing the old dam would require work on the stream, mitigation strategies were also needed to avoid causing damage to the fishery. It was important to confirm the presence of fish both above and below the dam before developing our plans.

In the spring of 2017, Ontario Parks staff placed dip nets at several points along the creek. This helped identify the types of fish species that inhabited this stream and establish baseline data for the site. It also allowed us to track the benefits that eliminating the landfill would have for the fishery over time.

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Our research confirmed the presence of Brook Trout above the dam site, and Brook Trout, Coho Salmon, Sculpin and Longnose Dace below the dam at the creek outlet.

With fisheries monitoring and environmental assessments completed, we were ready to remove the dam.

We take several steps to do this safely. We install sediment filters before starting work. We avoid working in the water during certain key periods in the life cycle of fish and their habitat. Lastly, we reseeded the stream bank after the project, providing erosion control.

All of these actions helped ensure fishery compliance and restorative success.

After a few days of hard work, the dam was successfully removed. We are happy to say that our habitat restoration was successful!

Removal of the dam helped support the resilience of the aquatic ecosystem and contributed to Ontario Parks’ goal of promoting ecological integrity.

Landfill Post Removal

To learn more about Ontario Parks’ commitment to ecological integrity, click here.