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Numerical data in tables

Survival of Downstream Migration

National Marine Fisheries Service
December 21, 2000

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

Survival of 1000 Juvenile 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 600 959 953 709 967 967 375 967 927
Dam 565 933 929 668 941 944 353 936 900
Little Goose Pool 454 872 880 631 908 863 212 797 803
Dam 428 858 850 595 894 839 200 777 760
Lower Monumental Pool 366 810 823 503 870 839 136 704 729
Dam 345 768 777 473 827 797 129 658 678
Ice Harbor Pool 287 721 720 424 806 755 84 598 628
Ice Harbor Dam 281 704 705 415 786 739 82 586 615
McNary Pool 221 658 653 360 769 702 46 517 557
Dam 212 641 637 340 748 684 45 502 543
John Day Pool 139 548 562 263 658 620 16 400 452
Dam 133 532 547 251 638 605 15 388 441
The Dalles Pool 115 509 524 232 627 587 11 361 417
Dam 102 463 476 205 570 533 10 328 379
Bonneville Pool 79 427 440 176 553 503 5 287 340
Bonneville Dam 74 403 415 165 519 473 5 272 322
 
Direct Mortality
Lower Snake River
4 Dams & 4 Pools
72% 30% 29% 58% 21% 26% 92% 41% 38%
Direct Mortality
Columbia River
4 Dams & 4 Pools
21% 30% 29% 25% 27% 26% 8% 32% 29%
Direct Mortality
Combined
8 Dams & 8 Pools
93% 60% 58% 83% 48% 52% 99% 73% 68%
Mortality of 8 Dams 12% 20% 17% 18% 23% 21% 5% 18% 22%
Mortality of 8 Pools2 81% 40% 41% 65% 25% 31% 95% 54% 47%
Indirect Mortality occurring 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

CAVEAT: Sub-yearling data has been called into question following this publication in 2000.
More caveats discussed in Appendix D of FCRPS 2000 Biological Opinion.

Red indicates 10% mortality or more

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

Draft 2000 FCRPS Biological Opinion, Appendix B
Data Reformatted from Tables B-7 through B-23
& Updated by Final 2000 FCRPS BiOp Table 6.2-7


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
Previously posted table based on Draft BiOp 7/27/00 Appendix B
FCRPS 2000 Biological Opinion (rather large at 21.4 megabytes)
Appendix D FCRPS 2000 Biological Opinion


National Marine Fisheries Service (NMFS)
Survival of Downstream Migration, Compiled from Tables B-7 through B-23, Appendix B
Updated with Final 2000 FCRPS Biological Opinion, Table 6.2-7, Chapt 6
Final FCRPS Biological Opinion, December 21, 2000

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