Opeongo Lake Dam Replacement

Work on this project included the demolition of the existing stop log dam built in 1955 and replacement with a three-level self-operating weir dam, total length was 42 meters – three times the original dam size. The dam was constructed on Annie Bay located on Lake Opeongo, the largest lake in Algonquin Provincial Park.

Also involved in this project was the construction of a diversion channel designed for the five-year storm water flow of 5.5m3 per second. The Diversion Channel, designed in-house by Maple Reinders, also included a 2-meter-high fish jump to prevent invasive species from travelling upstream to Lake Opeongo.

Culverts were placed under the existing dirt roadway to allow travel from one side of the dam to the other and a stop log system was put in place to control flow. A cofferdam, constructed of blasted rock from the park and lined with an impermeable plastic barrier, was also placed in front of the old dam to allow for a dry and safe work area.