FRANK L. CASSIDY JR.

"Larry"

CHAIRMAN

Washington

Tom Karier

Washington

NORTHWEST POWER PLANNING COUNCIL

851 S.W. SIXTH AVENUE, SUITE 1100

PORTLAND, OREGON 97204-1348

ERIC J. BLOCH

VICE CHAIRMAN

Oregon

John Brogoitti

Oregon

Jim Kempton

Idaho

Judi Danielson

Idaho

Fax:

503-820-2370

Phone:

503-222-5161

1-800-452-5161

Internet:

www.nwcouncil.org

Stan Grace

Montana

Leo A. Giacometto

Montana

June 13, 2001

Note: This staff issue paper is a preliminary analysis only. It has not been reviewed or

approved by the Northwest Power Planning Council and should not be cited as a Council

endorsement of any action based upon its content. Comments on this issue paper will be

accepted through Friday, June 22, 2001. The Council will discuss the findings of this analysis

at its next regular meeting in Pendleton, Oregon on June 26-27, 2001.

ISSUE PAPER:

ANALYSIS OF FEDERAL COLUMBIA RIVER POWER SYSTEM OPERATIONS ON

FISH SURVIVAL DURING SUMMER 2001

(COUNCIL DOCUMENT 2001-14)

This issue paper summarizes the results of a staff analysis that examined the effects of summer

spill and fish transport on the survival of outmigrating juvenile fall chinook. In particular, the

analysis focuses on the total system survival of ESA-listed Snake River fall chinook and unlisted

Hanford Reach fall chinook.

Caveats

• The base case 2001 operational configurations and spill levels are significantly different from

a normal water year. In 2001, Biological Opinion operations start from significantly reduced

spill and increased transportation levels. The findings of the analyses are applicable to 2001

water conditions and may not apply to other years.

• Good empirical survival data does not exist for 2001 water conditions. Hydroproject survival

estimates used in the model were obtained from 1994 to 1999 survival studies which may or

may not accurately reflect 2001 survivals.

• The analysis does not consider all populations of fall chinook. Besides the Snake River and

Hanford Reach, there are several other small, naturally spawning populations of fall chinook

that migrate during the summer months. Likewise, the analysis does not examine the impact

to various hatchery stocks of fall chinook that also migrate during the summer.

Methods

• Council staff used a version of the Simulated Passage Model (SIMPAS) to analyze the

relative effects of various spill and transportation alternatives on fish survival in the Snake

River and upper Columbia River basins.1 SIMPAS is a spreadsheet model developed by the

NMFS Hydro Program staff that uses empirical fish passage data to estimate relative juvenile

survival through the hydrosystem for various alternatives. The model was used by the

 

1

 A description of SIMPAS and model documentation can be found in Appendix D of the 2000 Biological Opinion.
Federal Biological Effects Team to help develop the 2000 Biological Opinion and is

currently used to analyze the relative consequences of hydropower operational changes on

the survival of listed stocks.

• The NMFS Simulated Passage Model (SIMPAS2) Version 1.0 was used for the analysis.

• Flows for 2001 were estimated by averaging 1944 and 1977 summer flows. Flows used in

the analysis were Snake River, 28 kcfs; Lower Columbia River, 122 kcfs.

• Transportation survivals were adjusted using “D values” found in the 2000 Biological

Opinion.

• Total system survival was calculated by summing in-river juvenile survival with “Dadjusted” transport survival.

Spill and Transport Scenarios

• Under the 2000 Biological Opinion, no spill will occur during the summer months at

collector dams and all juveniles collected at those projects will be transported. This

transportation operation is assumed for all model runs.

• Staff evaluated five different spill alternatives. The base case approximates the spill levels

called for under the 2000 Biological Opinion. Other alternatives assumed decreasing levels

of spill at the various projects. Spill levels for the alternatives are summarized in Table 1.

• Spill in megawatt-months (for one month) was estimated for each alternative.2

Table 1. Operational Alternatives with approximate megawatt-months in spill.

PROJECT

BASE CASE

(BIOP)

1000 MW-MOS3

ALT. 1

600 MW-MOS

ALT. 2

400 MW-MOS

ALT. 3

200 MW-MOS

NO SPILL

0 MW-MOS

Bonneville

92 kcfs night

75 kcfs day

50 kcfs night

50 kcfs day No spill No spill No spill

The Dalles

40% of flow for

24 hours

40% of flow

for 24 hours

40% of flow

for 24 hours

30% of flow

for 24 hours No spill

John Day 72 kcfs for 12

hours at night

30% of flow

for 12 hours at

night

30% of flow

for 12 hours at

night

No spill No spill

McNary No spill No spill No spill No spill No spill

Ice Harbor

20 kcfs for 24

hours No spill No spill No spill No spill

Lower

Monumental No spill No spill No spill No spill No spill

Little Goose No spill No spill No spill No spill No spill

Lower

Granite No spill No spill No spill No spill No spill

 

2

 Calculated mw-months based on assumed flow and spill levels used in this analysis. The mw-months give a

relative idea on how the various alternatives compare to one another. Power factors (H/K values) used to calculate

mw-months were obtained from federal agencies’ worksheets.

3

 Biological Opinion spill levels are restricted by powerhouse requirements at Ice Harbor (8.5 kcfs), John Day (50

kcfs) and Bonneville (50 kcfs).
Results

Tables 2 through 5 summarize the results of implementing the different alternatives.

Table 2. Starting with 1,000 fish at the head of Lower Granite reservoir, the number of

transported and inriver Snake River fall chinook arriving below Bonneville Dam for

different alternatives.

SNAKE RIVER FALL

CHINOOK

NO. OF FISH

TRANSPORTED

BELOW

BONNEVILLE

NO. OF INRIVER

FISH ARRIVING

BELOW

BONNEVILLE

TOTAL NO. OF FISH

ARRIVING BELOW

BONNEVILLE

Base Case 164 1 165

Alternative 1 162 1 163

Alternative 2 162 1 163

Alternative 3 162 1 163

No Spill 162 0 162

Table 3. Total system survival of 1,000 juvenile Snake River fall chinook from Lower

Granite Dam pool to below Bonneville Dam for various alternatives (total system survival =

no. “D-adjusted” transported fish + no. inriver fish). Relative change in total system

survival from base case for each alternative is calculated.

SNAKE RIVER FALL

CHINOOK

TOTAL SYSTEM

SURVIVAL TO

BELOW

BONNEVILLE

NO. OF ADDITIONAL

FISH LOST FROM

BASE CASE

% CHANGE FROM

BASE CASE

Base Case 41

Alternative 1 40 -1 -2.9%

Alternative 2 40 -1 -3.0%

Alternative 3 40 -1 -3.0%

No Spill 39 -2 -4.1%

Table 4. Starting with 1,000 fish at the head of McNary reservoir, the number of

transported and inriver Hanford Reach fall chinook arriving below Bonneville Dam for

different alternatives.

HANFORD REACH

FALL CHINOOK

NO. OF FISH

TRANSPORTED

BELOW

BONNEVILLE

NO. OF INRIVER

FISH ARRIVING

BELOW

BONNEVILLE

TOTAL NO. OF FISH

ARRIVING BELOW

BONNEVILLE

Base Case 500 125 625

Alternative 1 500 122 622

Alternative 2 500 120 620

Alternative 3 500 117 617

No Spill 500 112 612
Table 5. Total system survival of 1,000 juvenile Hanford Reach fall chinook from McNary

Dam pool to below Bonneville Dam for various alternatives (total system survival = no. “Dadjusted” transported fish + no. inriver fish). Relative change in total system survival from

base case for each alternative is calculated.

HANFORD REACH

FALL CHINOOK

TOTAL SYSTEM

SURVIVAL TO

BELOW

BONNEVILLE

NO. OF ADDITIONAL

FISH LOST FROM

BASE CASE

% CHANGE FROM

BASE CASE

Base Case 245

Alternative 1 242 -3 -1.2%

Alternative 2 240 -5 -2.0%

Alternative 3 237 -8 -3.3%

No Spill 232 -13 -5.3%

Discussion

Snake River Fall Chinook

• Spill has little to no benefit for Snake River fall chinook as compared to the operations in

the base case. The number of fish lost from reducing spill is negligible. Under the

Biological Opinion spill levels, total system survival is 41 fish out of 1,000. By

eliminating spill at all dams, total system survival is 39 fish out of 1,000.

• Snake River fall chinook do not benefit from spill operations primarily because: 1) The

survival of juveniles migrating through Lower Granite reservoir is very low and fewer

fish reach federal projects; and 2) Most of the remaining fish are transported, leaving

very few in-river.

Hanford Reach Fall Chinook

• Spill has some benefit to Hanford Reach fall chinook as compared to the operations in the

base case. More Hanford Reach fish remain in the river than Snake River fish because

McNary Dam is the only project where Hanford Reach fish are collected and transported.

Under the Biological Opinion spill levels, total system survival is 245 fish out of 1,000.

By eliminating spill at all dams, total system survival is 232 fish out of 1,000.

• The reduction in survival caused by eliminating spill may be relatively innocuous for the

population. Hanford Reach fall chinook are a healthy population that generally exceeds

escapement goals and maintains mainstem harvest rates of about 30 percent, and overall

harvest/exploitation rates (which includes ocean harvest) of about 40 to 50 percent.4

• For migrating fall chinook juveniles, spill provides the greatest benefit in the following order

of priority: 1) The Dalles; 2) John Day; 3) Bonneville; 4) Ice Harbor.

• BPA is now forecasting lower summer flows than those used in this analysis. Depending on

how these flows are allocated between spill and powerhouse requirements, these lower flows

may tend to decrease Biological Opinion spill levels and make spill comparatively less

effective in increasing fish survival.

• The results of this analysis for Snake River fall chinook are different from the results

presented in the March 30, 2001 issue paper (Council Document 2001-6). In the March 30

issue paper, Snake River fall chinook total system survival was calculated to be

approximately 11%. The latest results show a total system survival closer to 4%. The

 

4

 John Skidmore, BPA, personal communication.
discrepancy is primarily due to lowering the Lower Granite reservoir survival estimates

(recent NMFS data) for fall chinook.

• Hanford Reach fall chinook survival in the current analysis is generally the same as the

results reported in the April 30, 2001 addendum (Council Document 2001-9). The slight

discrepancy is due to variations in spill assumptions at the federal dams.

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