Fisheries Habitat Construction at Big Island Marsh

A Fisheries Act Authorization from DFO is required by Parks Canada, Trent Severn Waterway (TSW) for impacts on fish habitat associated with dam construction projects at TSW Trenton Dam 1 and Glen Miller Dam 3. The Authorization includes provisions for offsetting measures.

The construction of the Big Island causeway in the 1950's and decreased water flows between the island and the mainland have caused the channels to be filled in with silt, and cattails now cover the entire area from the island to the mainland. Parks Canada is proposing to expand on existing fish habitat enhancements at the Big Island Marsh by constructing a new channel and widening/deepening of 2 existing channels. Cattail marsh vegetation will be removed to a width of 10 m and depths up to 3.0 m, in order to ensure these areas stay open into the future. This project is expected to result in the enhancement of fish habitat at the Big Island Marsh.

Latest update

July 27, 2021 - The assessment decision statement has been issued to the proponent.



Trent-Severn Waterway National Historic Site
P.O. Box 567
Peterborough, Ontario K9J 6Z6
Telephone: 705-750-4900 or 1-888-773-8888

  • Location

    • Trent-Severn Waterway National Historic Site (Ontario)
  • Nature of Activity

    • Other, not otherwise specified
  • Assessment Status

  • Start Date

  • Proponent

    Parks Canada
  • Authorities

    • Parks Canada Agency
  • Assessment Type

    Project on federal lands
  • Reference Number


This map is for illustrative purposes. The markers represent the approximate locations based on available data. More than one marker may be identified for a given assessment.


Nearby assessments

...within 200 kilometres
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