The Salmon River Diversion Project is located in Canada’s central Vancouver Island about 30 km west of Campbell River. The Salmon River Diversion Dam was built to divert water from the Salmon River via an engineered canal, into Brewster Lake, and then into Lower Campbell Lake. The diverted water is used for power generation at Ladore and John Hart generating stations.
At the time of construction, a natural obstruction in the Salmon River below the diversion dam prevented fish from migrating upstream. Therefore, there was only a minor instream flow release and no provisions for fish passage was required as part of the diversion project. Decades after construction, fish passage improvements were completed downstream and stocking programs were undertaken upstream of the diversion. Although both the fish screen and fish ladder are successful in aiding fish passage, neither structure performs at a high enough efficiency based on current standards. As a result, BC Hydro was carrying out a project to replace these structures in an effort to increase the efficiency of the upstream and downstream fish passage at the Salmon River Diversion.
McMillen Jacobs provided an alternative and feasibility analysis as well as developed the preliminary design for the refurbishment of the Salmon River Diversion Dam and Canal, the Upstream Fish Passage, and Downstream Fish Entrainment Mitigation measures. As part of the concept design, the McMillen Jacobs team investigated options to:
- Address improvements at the timber crib dam and lined canal so that BC Hydro can safety pass the 15 m3/s design flow
- Improve the design/configuration of existing facility headworks including the sluice way, canal intake / trashracks, and trimming weir to increase effectiveness of debris passage and fish passage
- Improve the effectiveness of the upstream fish passage past the dam as per the Salmon River Upstream Fish Passage Objectives
- Improve downstream fish passage by diverting fish out of the Salmon River Diversion canal and back into the Salmon River natural channel with a target efficiency of at least 90% at the screen (diversion of fish in good condition into the natural channel)
The upstream passage and headworks components of the project were developed to a 90% completion level. The Dam, Canal, and Downstream Fish passage were developed to approximately 15% level. BC Hydro re-evaluated the overall project and elected to decommission the project.