96 Survival of Downstream Migration, Draft BIOP, Tables B-7 through B-23 Appendix B

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

	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:

The juvenile survival rates shown are based on juvenile passage studies only and cannot be used to infer the likelihood of adult returns

The juvenile survival rates shown, as well as the input passage parameters, are point estimates, i.e., confidence intervals are not calculated or implied.

The model does not contain a time-step function so both inputs and outputs are scaled to seasonal averages.

The model does not account for the potential effects of various fish passage options on forebay passage in terms of reducing delay, residence time, or predation

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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