An Investigation of Louvers as a Method of Guiding Juvenile Pacific Salmon

Louvers may be generally described as a series of vertical slats placed in a diagonal line across the migratory path of downstream migrating fish. Each slat is set at right angles to the direction of flow. The migrants, upon approaching the slats, tend to avoid them while continuing downstream and are thus guided to a bypass at the downstream end of the louver line. In 1957, 1958, and 1959 tests were conducted on an experimental louver installation on the Puntledge River in an attempt to provide a satisfactory solution to the problem of screening downstream migrating chinook salmon fry (Oncorhyncus tshawytscha) from the water intake canal of the Puntledge River powerhouse. Research was continued at Robertson Creek in 1960, 1961, and 1962 to evaluate the louver principle for guiding sockeye salmon (O. nerka) and coho salmon (O. kisutch) smolts from the water intake canal of a proposed hydroelectric project on the Stamp River System. Both of these river systems are located on Vancouver Island, British Columbia. This report will summarize the results of the experiments carried out during the period of louver testing. An appraisal of louvers as a method for deflecting juvenile salmon is presented and an attempt is made to indicate areas where further research is required. The data are presented in two parts: the first, dealing with the Puntledge River tests and the second, covering tests conducted at Robertson Creek.