Behavior and Survival for Juvenile Salmonids Passing Ice Harbor Dam during reduced and BiOp spill treatments, 2006-07 Gordon Axel, Eric Hockersmith, and Darren Ogden NOAA Fisheries Service Northwest Fisheries Science Center Fish Ecology Division U. S. Army Corps of Engineers Northwestern Division Walla Walla District The data I will present represents 2 years of a radiotelemetry evaluation with an RSW operating at Ice Harbor Dam.

Results - Ice Harbor Dam Spring Operations 2006 (High Flow) Reduced BiOp 2007 (Low Flow) Total River Flow (kcfs) 120 144 75 79 Mean Training Spill (kcfs) 32 76 15 46 % Spill Training 26% 52% 20% 58% Mean RSW (kcfs) 8 8 % RSW Spill 7% 6% 11% 10% During both spring evaluations, we had similar treatments: a reduced spill of about 30% of the river, and a BiOp spill which incorporated 45 kcfs during the day and gas cap at night. We observed two very different flow years which provided a great chance to see differences in behavior and survival associated with each. I would like to point out that although flow through the RSW was a constant 8 kcfs in both years, the percentage of the river flow through the RSW was 4% higher during the low flow year. This seemed to have a large impact on fish approach and passage behavior.

Results - Yearling Chinook Salmon: First Approach BiOp Spill Reduced Spill % at non-turbine routes: 88% % at non-turbine routes: 80% 2006 % at non-turbine routes: 87% % at non-turbine routes: 80% For yearling Chinook salmon, first approach within 5 meters of the concrete was much higher in 2007 than in 2006, by nearly 30%. I’ve noted the percentage of fish approaching non-turbine routes in the upper right corner to give an idea of how well the spill pattern is drawing fish away from the powerhouse. 2007

Results - Yearling Chinook Salmon: Passage Distribution BiOp Spill Reduced Spill % thru non-turbine routes: 95% % thru non-turbine routes: 93% 2006 % thru non-turbine routes: 98% % thru non-turbine routes: 92% When we look at passage distribution for these fish we see that although the percentage through non-turbine routes remains high, yearling Chinook aren’t continuing on through the RSW. During BiOp spill they utilize the training spill and during the reduced spill we observed 16-20% use the bypass system. 2007

Results – Juvenile Steelhead: First Approach BiOp Spill Reduced Spill % at non-turbine routes: 91% % at non-turbine routes: 83% 2006 % at non-turbine routes: 96% % at non-turbine routes: 88% For Steelhead, we also saw an increase in the percentage of first approaches at the RSW with the increased percentage of surface flow. We also observed lower rates of approach near the powerhouse. 2007

Results – Juvenile Steelhead: Passage Distribution BiOp Spill Reduced Spill % thru non-turbine routes: 99% % thru non-turbine routes: 98% 2006 % thru non-turbine routes: 99% % thru non-turbine routes: 99% Again, though we still have some reluctance to continue on through the RSW, more so during 2006 when the flow queues may have pulled more fish to the powerhouse. However, FGE is extremely high for these fish and overall passage through non-turbine routes for steelhead was near 100%. 2007

Survival Results – Yearling Chinook Salmon 2006 (High Flow) Reduced BiOp 2007 (Low Flow) Spill Survival 96% 96% 97% 96% RSW Survival 95% 96% 95% 95% Dam Survival 91% 92% 94% 92% Concrete Survival In terms of survival for spring migrants, we observed no statistical difference between treatments or flow years. This is yearling Chinook. Forebay delay was slightly lower during BiOp spill treatments, but Dam survival which incorporates forebay loss does not indicate a significant difference between treatments. Forebay Delay (h) 1.8 1.1 2.0 1.5

Survival Results – Juvenile Steelhead 2006 (High Flow) Reduced BiOp 2007 (Low Flow) Spill Survival 100% 100% 97% 97% RSW Survival 100% 98% 97% 98% Dam Survival 90% 94% 94% 93% Concrete Survival 100% 100% 97% 96% For Steelhead, similar results: high survival, no statistical differences between treatments. Forebay Delay (h) 1.9 1.1 1.8 1.7

Results - Ice Harbor Dam Summer Operations 2006 (High Flow) Total River Flow (kcfs) 56 Mean Training Spill (kcfs) 22 % Spill Training 40% Mean RSW (kcfs) 8 % RSW Spill 14% During summer operations at Ice Harbor for Subyearling Chinook we had one treatment due to lower flow conditions. Again, I would like to point out that the percentage of spill through the RSW was even higher at 14%.

Results - Subyearling Chinook Salmon: First Approach % at non-turbine routes: 93% For subs, we had over 60% first approach in the near vicinity of the RSW.

Results - Subyearling Chinook Salmon: Passage Distribution % thru non-turbine routes: 98% The passage distribution suggests that subyearlings tended to pass the structure with somewhat less of an aversion as we observed with spring outmigrants and nearly 98% passing through non-turbine routes.

Survival Results – Subyearling Chinook Salmon 2006 (High Flow) Spill Survival 99% RSW Survival 98% Dam Survival 95% Concrete Survival Survival results for subs show very high survival at the project with a median forebay delay of about 2 hours. Forebay Delay (h) 2.0

Conclusions No difference in survival by species, treatment, or flow years BiOp spill slightly reduces forebay residence; though does not significantly alter forebay loss Increasing percentage of river flow through RSW by 4% increased passage through RSW by 8% for yearling Chinook and 36% for steelhead Increasing the forebay depth by one foot at Ice Harbor could increase percentage of flow through the RSW by 2% during a high flow year and 3% during a low flow year So the take home messages from 2 years of evaluation at Ice Harbor: -No differences in survival by species, treatment, or flow years -BiOp spill slightly reduces forebay delay, though does not affect forebay loss -By increasing the surface flow queues by 4%, we increased passage over the RSW for yearling chinook by 8% and for steelhead by 36% -Increasing the forebay depth by a foot might provide a benefit by pulling more fish from the powerhouse and passing them through safer routes.