|Document Type:||Contract Report|
|Title:||Post-construction evaluation of the new juvenile bypass system and guidance screen modifications at John Day Dam, 1998|
|Author/Editor:||R. F. Absolon, Benjamin P. Sandford, Douglas B. Dey|
|Publisher:||National Marine Fisheries Service|
|Contracting Agency:||U.S. Army Corps of Engineers. Portland, Oregon|
Modifications to the John Day Dam juvenile salmonid sampling facility and bypass system were completed and the system was ready for operation in April 1998. This bypass system is similar to others constructed during the 1990s at Little Goose, Lower Monumental, Ice Harbor, and McNary Dam. The John Day facility does not have transportation raceways, but does include a hydraulic jump and wetted separator, which are unique to this project. We examined juvenile salmonids for descaling and gross external injuries, analyzed blood samples for evidence of stress build-up, and evaluated efficiency of the sampling system.
Hatchery yearling Chinook salmon and steelhead were released at several locations in the system, including the collection channel adjacent to Turbine Units 1, 9, and 15, at the crest gate, and at both the upstream and downstream ends of the primary dewatering structure. These fish were recaptured at the sampling facility and evaluated for signs of injury. Injury levels for both yearling Chinook salmon and steelhead were low, and most could be attributed to the hose used for collection channel releases.
Blood plasma samples were collected from 180 run-of-river yearling Chinook salmon and steelhead, and samples were assayed for levels of cortisol, lactate, and glucose. Fish of both species were collected from the gatewell, the pre-separator, and the pre-sample tank. The levels of all three plasma indicators were similar to those found in other facility evaluations.
Yearling Chinook salmon showed a significant increase in mean levels of both cortisol and glucose in the pre-separator and pre-sample tank samples as compared to the gatewell samples. No differences were noted in lactate levels from any of the three sites for yearling Chinook salmon.
Juvenile steelhead also showed a significant increase in cortisol levels when collected from the pre-separator and pre-sample tank locations compared to the gatewell site. No differences were found in lactate or glucose levels between any of the three sample locations.
Efficiency of the sampling system was evaluated using in-river PIT-tagged fish. The percentage of PIT-tagged fish diverted into the smolt monitoring sample was calculated as the number of fish diverted into the sample divided by the total number of fish passing the facility during the time the sample was set at each sample rate. This was compared to the sample rate set at the sampling facility. For sample rates of 0.67, 1.33, 2.0, and 3.33% there was no statistical difference between observed and set rates. The observed rate was statistically higher than the set rate for 1.0%, while the observed rate was statistically much lower for both 5.0 and 10.0%.