Community Update: Conservation During Construction - Protecting Fish Habitat

Trent-Severn Waterway National Historic Site

Over the last three years, Parks Canada has announced over $615 million in investments into the locks, dams, bridges and other infrastructure along the Trent-Severn Waterway. The mandate and values that define Parks Canada have also defined the approach to infrastructure investment: preserving natural and cultural heritage; engaging with Indigenous peoples, partners, communities and canal users; and environmental protection and conservation.

Parks Canada’s environmental team is engaged right from the start of each project; scrutinizing project plans and processes and looking for ways to avoid, reduce or offset a project’s potential to impact our environment. In some cases, other agencies are responsible for various aspects of an area’s ecology – water quality for example. Parks Canada engages often with these agencies to obtain data, coordinate conservation efforts, and seek approval.

Monitoring of the natural environment occurs before, during and after a project. This spring our team has been collecting baseline data and monitoring the Walleye spawn near several Trent-Severn Waterway dams and their watercourses. This includes both counting numbers of spawning adults, and collecting data on egg survival. The data obtained provides essential information to Parks Canada and our partner agencies on the quantity and condition of existing Walleye habitat on the Trent-Severn Waterway, how it can be protected through construction or rehabilitated, and ways that Parks Canada can enhance it for the future. 

An environmental worker in an orange vest takes notes beside a rapids A Biologist with Niblett Environmental Associates Inc. collecting field data on behalf of Parks Canada in the Six Mile Lake / Port Severn area

Habitat Enhancement

Otonabee River Dams 

The construction activities at the dam at Lock 19, and at the other dams on the Otonabee River will have an impact on spawning habitat both during construction, and because the new dams will have a slightly wider footprint for additional stability. Before construction begins, existing habitat in other nearby locations will be supplemented to offset any impacts. In addition, habitat restoration and enhancement will occur within the project areas following construction. Through these efforts the goal is to achieve an overall net benefit for spawning habitat following construction.

The downstream portion of a dam 

Maintaining Water Flow

Talbot River 

The Talbot Dam, which is being replaced, sits in the basin between Talbot Lock 38 and Portage Lock 39. Outflows from the dam diverge from the canal cut and go to Lake Simcoe via the Talbot River. This area is important for Walleye and White Sucker. Parks Canada’s water management accommodates the spring spawn for these species and the construction project has been designed to continue these measures by building one sluice of the new Talbot Dam at a time.

A flowing river 

Finding the Right Timing

Port Severn Dams 

The channel below the pool in the foreground (Port Severn Dam E, July 2017) is the primary Walleye spawning area in Severn Sound. This area is also an important spawning area for Lake Sturgeon. Parks Canada worked with the Ontario Ministry of Natural Resources and Forestry to better understand the timing of the spawn periods. This combined with a desire to construct outside of the tourism season, led to an adjustment in both the timing of the project at Port Severn Dam E, and how it would be implemented. 

A rocky area of water 

For More Information

This scale of investment hasn’t happened since the TSW was originally constructed, between 98 and 185 years ago. Be a part of all the action! To receive email updates about any of our projects, please contact us at and include the project name or area in the subject heading. For online news about projects in your area, please visit

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