Session A6- Nature-like fishway construction, Digdeguash Lake, N.B, a case study in stability during flood events

• Main Authors: Jenkins, Ron, Corr, Aaron, Parish, John
• Format: Text
• Language: unknown
• Published: ScholarWorks@UMass Amherst 2011
• Subjects: Canada; Atlantic salmon
• Online Access: https://scholarworks.umass.edu/fishpassage_conference/2011/June28/29

In the summer of 2010 a nature-like fishway was constructed around a two meter tall dam at the outlet of Digdequash Lake on Linton Stream, which drains into the Magaguadavic River near St. George, New Brunswick, Canada. The goal of the project was to reestablish historic fish passage as compensation for a gas line project in the region. The project location was selected from several other potential sites through consultation ·with DFO, the Atlantic Salmon Federation, and staff at the Department of Natural Resources. The recommendations identified brook trout, anadromous Atlantic Salmon, American eel, and gaspereau as the target species for the project. An assessment of the site, condition of the dam, water and access needs of a nearby salmon hatchery and construction cost concluded that the best alternative for fish passage was a nature-like channel around the north side of the dam. The fish passage channel had a controlled inlet, was constructed of large rock and cobble, was sealed with bentonite at all locations up gradient of the dam, had a step-pool structure, and ensured upstream and downstream fish passage during the spring and fall of the year. There was also a recreational boat landing on the north side of the dam that needed to be relocated to the north to accommodate the by-pass channel. Anecdotal evidence of fish passage was observed by members of the design and construction team. A multi-year fish monitoring and tagging program was planned to begin in the summer of 2011, however, the proposed study was interrupted by a greater than 100-Year storm event that occurred at the site in the spring of 2011. The flood breached the dam, leaving the nature-like fish passage in stable condition, ·with minor erosion of some of the bio-engineered bank features.