Northwest Fisheries Science Center

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Document Type: Contract Report
Center: NWFSC
Document ID: 5551
Title: Post-construction evaluation of the juvenile bypass system at John Day Dam, 1999
Author/Editor: R. F. Absolon, Dean A. Brege, John W. Ferguson
Publication Year: 2000
Publisher: National Marine Fisheries Service
Contracting Agency: U.S. Army Corps of Engineers. Portland, Oregon
Contract Number: W66QKZ80354028
Pages: 14
Date: 2000

The John Day Dam juvenile salmonid sampling facility and bypass system reconstruction was completed and ready for operation in April 1998, at the beginning of the spring juvenile migration.  This bypass system is similar to others constructed at Little Goose, Lower Monumental, Ice Harbor and McNary Dams during the 1990s.  The John Day facility does not have raceways to hold fish for transportation, but does include a hydraulic jump and a wetted separator which are unique to this project.

In 1998, we released hatchery yearling Chinook salmon Oncorhynchus tshawytscha and steelhead O. mykiss at several locations in the bypass system.  Fish were recaptured at the sampling facility and examined for descaling and gross external injuries.  Blood plasma samples were collected to evaluate indicators of stress, and the efficiency of the sampling system was evaluated.  Evaluation of the adult sampling system could not be completed in 1998 due to deficiencies in several of its components.

In 1999, we evaluated the facility to ensure the safe passage of fry sized salmonids.  Three groups of 200 marked hatchery subyearling Chinook fry were released to the elevated flume in the area of the crest gate and recaptured at the sampling facility.  We were able to recapture 599 of 600 fish released, and none showed any signs of injury or descaling.

Based on results from this test, we concluded that the facility passed salmonid fry without delay or injury.  Evaluations conducted in 1998 and 1999 indicate that juvenile salmonids pass the John Day juvenile bypass facility without injury or undue delay.

Deficiencies in the adult portion of the facility  were corrected during winter 1998-99.  This part of the facility was not evaluated in 1999 because a suitable release location for adult test fish could not be determined.  We recommend that run-of-river adult salmonids be monitored each year to determine if there are problems with the adult sampling system.  If problems are observed, consideration should be given to conducting an adult evaluation that includes the gatewell environment, with marked adult salmonids initially released to a gatewell.