noaa fisheries service northwest fisheries science center fish ecology division

Behavior and Survival for Juvenile Salmonids Passing Ice Harbor Dam during reduced and BiOp

spill treatments, 2006-07

NOAA Fisheries ServiceNorthwest Fisheries Science Center

Fish Ecology Division

U. S. Army Corps of EngineersNorthwestern Division

Walla Walla District

Gordon Axel, Eric Hockersmith, and Darren Ogden

Results - Ice Harbor Dam Spring Operations

2006 (High Flow)Reduced BiOp

2007 (Low Flow)Reduced BiOp

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 8 8

% RSW Spill 7% 6% 11% 10%

Results - Yearling Chinook Salmon: First Approach20

0720

06

BiOp Spill Reduced Spill

% at non-turbine routes: 88% % at non-turbine routes: 80%

% at non-turbine routes: 87% % at non-turbine routes: 80%

2007

2006

BiOp Spill Reduced Spill

% thru non-turbine routes: 95% % thru non-turbine routes: 93%

% thru non-turbine routes: 92%% thru non-turbine routes: 98%

Results - Yearling Chinook Salmon: Passage Distribution

2007

2006

BiOp Spill Reduced Spill

% at non-turbine routes: 91% % at non-turbine routes: 83%

% at non-turbine routes: 96% % at non-turbine routes: 88%

Results – Juvenile Steelhead: First Approach

BiOp Spill Reduced Spill

2007

2006

% thru non-turbine routes: 99% % thru non-turbine routes: 98%

% thru non-turbine routes: 99%% thru non-turbine routes: 99%

Results – Juvenile Steelhead: Passage Distribution

Survival Results – Yearling Chinook Salmon

2006 (High Flow)Reduced BiOp

2007 (Low Flow)Reduced BiOp

Spill Survival 96% 96% 97% 96%

RSW Survival 95% 96% 95% 95%

Dam Survival 91% 92% 94% 92%

Concrete Survival 96% 96% 95% 96%

Forebay Delay (h) 1.8 1.1 2.0 1.5

Survival Results – Juvenile Steelhead

2006 (High Flow)Reduced BiOp

2007 (Low Flow)Reduced BiOp

Spill Survival 100% 100% 97% 97%

RSW Survival 100% 98% 97% 98%

Dam Survival 90% 94% 94% 93%

Concrete Survival 100% 100% 97% 96%

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%

Results - Subyearling Chinook Salmon: First Approach

% at non-turbine routes: 93%

Results - Subyearling Chinook Salmon: Passage Distribution

% thru non-turbine routes: 98%

Survival Results – Subyearling Chinook Salmon

2006 (High Flow)

Spill Survival 99%

RSW Survival 98%

Dam Survival 95%

Concrete Survival 98%

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