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Survival of Downstream Migration
Draft 2000 FCRPS Biological Opinion, Appendix B
Data Reformatted from Tables B-7 through B-23

National Marine Fisheries Service, July 27, 2000

Downstream migration through the 8 dams and reservoirs
of the Federal Columbia River Power System (FCRPS)

Survival of 1000 Fish Arriving at Lewiston, Idaho

  Average Best Year Worst Year
In sequence
heading downstream 		Sub-Yearling
Chinook
(1995-99) 		Yearling
Chinook
(1994-99) 		Steelhead
(1994-99) 		Sub-Yearling
Chinook
(1995) 		Yearling
Chinook
(1999) 		Steelhead
(1995) 		Sub-Yearling
Chinook
(1997)1 		Yearling
Chinook
(1994) 		Steelhead
(1994)
Lewiston, Idaho 1,000 1,000 1,000 1,000 1,000 1,000 1,000 1,000 1,000
Lower Granite Pool 599 942 909 709 969 967 375 949 750
Dam 565 916 886 668 943 944 353 919 728
Little Goose Pool 454 850 828 630 910 881 212 743 602
Dam 428 836 801 594 896 856 200 725 569
Lower Monumental Pool 366 798 767 502 871 853 136 678 508
Dam 345 756 725 472 828 811 129 634 473
Ice Harbor Pool 294 708 672 426 806 784 92 576 404
Ice Harbor Dam 287 691 658 417 787 767 90 564 396
McNary Pool 231 642 604 363 769 734 56 495 320
Dam 222 625 589 344 748 716 54 482 312
John Day Pool 143 531 512 264 658 660 17 376 204
Dam 136 515 499 252 638 644 16 365 199
The Dalles Pool 121 495 479 233 627 628 13 340 177
Dam 107 449 435 206 570 570 11 309 160
Bonneville Pool 84 415 393 178 554 544 7 269 127
Bonneville Dam 79 392 371 167 520 511 6 255 120
 
Direct Mortality
Lower Snake River
4 Dams & 4 Pools 		71% 31% 34% 58% 21% 23% 91% 44% 60%
Direct Mortality
Columbia River
4 Dams & 4 Pools 		21% 30% 29% 25% 27% 26% 8% 31% 28%
Direct Mortality
Combined
8 Dams & 8 Pools 		92% 61% 63% 83% 48% 49% 99% 75% 88%
Mortality of 8 Dams 12% 20% 20% 19% 24% 23% 5% 18% 13%
Mortality of 8 Pools2 80% 41% 43% 65% 25% 26% 95% 57% 75%
Indirect Mortality occuring later in life
from the effects of
8 Pools & 8 Dams
? ? ?       ? ? ?
  Sub-Yearling
Chinook 		Yearling
Chinook 		Steelhead Sub-Yearling
Chinook 		Yearling
Chinook 		Steelhead Sub-Yearling
Chinook 		Yearling
Chinook 		Steelhead
  Average Best Year Worst Year

Red indicates 10% mortality or more

Dam survival is modeled and Pool survival is calculated by substraction from empirical data.

1No Data available for 1994 Sub-Yearling Chinook. Sub-Yearling Chinook are typically Fall Chinook while Yearling Chinook are typically Spring/Summer Chinook

2No Data is available for mortality/survivability before dams were built but it was certainly much less than the current mortality.

Best professional judgement was used to develop some of the passage parameters, e.g., in some cases, fish passage data gathered at one dam during a single passage season was applied to several other similar hydrosystem projects.

Reach survival data is limited to NMFS PIT tag data collected during 1994-99. These years represent a range in flow and environmental conditions. In several years, reach survival data were extrapolated from some of the upper projects in the Snake River (on a per-mile basis) to the entire system. The reach survival estimates are point estimates roughly classified by the volume of runoff during the year in which the data were collected.

Although there may be uncertainty about the accuracy of the resulting pool and dam survival estimates, the BET and NMFS found that the model output for the years 1994-99 was reasonable and produced reach survival estimates similar to the empirical estimates. Once the model was calibrated to data for the current operation, the BET and NMFS considered it had a reasonable base case from which to make comparisons of additional model studies over a range of water conditions represented by water years 1994-99 of potential future juvenile fish passage actions.

Caveats of methodology:

Related Links:
Columbia Basin Salmon Recovery Strategy

National Marine Fisheries Service (NMFS)
Survival of Downstream Migration, Compiled from Tables B-7 through B-23, Appendix B
Draft Biological Opinion, July 27, 2000

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