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CSS Oversight CommitteeISAB

November 15, 2013

Comparative Survival Study Outcomes –

Experimental Spill Management

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Topics for today• CSS study• Long term survival studies• Background on spill• Experimental Spill Management

Design• Simulation results and next steps

Comparative Survival Study• A regional collaborative salmon and steelhead

life cycle monitoring program• Successfully implemented since 1998• Annually reviewed by the NPCC Independent

Scientific Advisory Board and the region• Analyses published in peer reviewed scientific

journals

Background• 40- 60 years of historical run

reconstruction data • 15 years of Comparative Survival

Study Data• 15 years of spill and dissolved gas

data and effects on juvenile migrants• Analyzed multiple lines of evidence

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NPCC Smolt-to-Adult Survival Goal- Recovery

• Achieve SARs averaging 4% for Snake River Chinook salmon and steelhead

SAR

NPCC Smolt-to-Adult Survival Goal- Recovery

• Achieve SARs averaging 4% for Snake River Chinook salmon and steelhead

SAR

NPCC Smolt-to-Adult Survival Goal- Recovery

• Achieve SARs averaging 4% for Snake River Chinook salmon and steelhead

SAR

3 4 5 6 7 8 dams

Decline in Snake R. Chinook & steelhead associated with dams…

Key Concepts:Is there evidence linking estuary and early-ocean mortality to the migration experience through the hydrosystem?

DELAYED Hydrosystem MORTALITY• Similar concept to smoking/lung cancer

Potentially 8 Dams

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ApproachWeight of evidence Multiple lines of evidence for relative importance of major factors influencing survival rates

CSS SARs (Chin & Sthd)

SARs (run rec. - Snake Chin & Sthd)

Spawner:recruit (Snake & John Day Chin)

3 4 5 6 7 8dams

1960 1965 1970 1975 1980 1985 1990 1995 2000 2005 2010

Environmental Contrast

Life cycle

Life stage

Prec

isio

n &

Spe

cific

ity

Key Studies• Petrosky and Schaller 2010 – Spill, water velocity and ocean conditions influence SARs

• Haeseker et al. 2012– Spill, water velocity and ocean conditions influence SARs

• Schaller et al. in press– Spill, water velocity and ocean conditions influence

Recruits/Spawner and SARs

• Over a dozen peer reviewed publications

Chinook

Steelhead

1997 1999 2001 2003 2005 2007 20090%

1%

2%

3%

4%

1997 1999 2001 2003 2005 2007 20090%

1%

2%

3%

4%

5%

SAR

Relative Variable Importance

SAR

Day N.Spill WTT Screens PDO0.0

0.2

0.4

0.6

0.8

1.0

1997 1999 2001 2003 2005 2007 20090%

1%

2%

3%

4%

1997 1999 2001 2003 2005 2007 20090%

1%

2%

3%

4%

5% Steelhead

Chinook

SAR

Relative Variable Importance

SAR

+- --

+- --Day N.Spill WTT Screens PDO

0.0

0.2

0.4

0.6

0.8

1.0

+

+

Delayed Hydrosystem Mortality• Multiple lines of evidence- – 3 fold decline in marine survival rate for Chinook– 2 fold decline in marine survival rate for

Steelhead

• CSS Workshop 2011– “The evidence presented for … delayed

mortality arising from earlier experience in the hydrosystem is strong and convincing.”– “ It is difficult to imagine how [other factors]

would align so well both in time and space with the establishment of the hydro system.”

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Summary of 2011 Workshop• Survival (in freshwater and marine) increases: • faster water velocity• increased spill • lower % transported

•Current FCRPS configuration:• Little ability to speed water velocity• Opportunity to further manage spill combined with surface passage to

reduce powerhouse passages

• Promising approach - management experiment to evaluate improvements to SARs by increasing voluntary spill- Adaptive Management approach

In-river Passage RoutesNon-powerhouse = Spill (traditional or surface spillway weirs)

Powerhouse = Turbine or juvenile collection/bypass

Submersible traveling screen

Collection channel

(3) Turbine

Forebay

Tailrace

(1) Spillway Reservoir

(2) Juvenile Bypass Systems

Gatewell

Spill Benefits

• Historic data has consistently shown a juvenile survival advantage.

• Spill is a mitigation measure that can be provided in every flow year.

• Spill can be provided without impact to reservoir elevations.

Risk Based Spill Program

• Survival benefits of spill > potential TDG related mortality

• Adaptive Management approach-supported by empirical observations:– Juvenile survival– SARs– TDG effects

Variability of Spill 1995-2012

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Summary of GBT Samples (1995-2012)

as a function of TDG

100 to 105 106 to 110 111 to 115 116 to 120 121 to 125 126 to 130 130 to 1390%

5%

10%

15%

20%

25%

0.2% 0.3% 0.9% 0.6%

2.5%

4.9%

7.7%

PctFinGBTPctRank1PctRank2PctRank3PctRank4

Upstream Tailwater TDGS

Perc

ent o

f Fis

h w

ith F

in G

BT

223,921 fish examined

In Preparation for 2013 Workshop

• Develop estimates of the amount of water that could be spilled (spill caps) at each of the hydroprojects on the Lower Snake and Columbia rivers for the various scenarios modeled for the 2013 workshop.

• Choose representative flow years for prospective modeling.

Summary of 2013 Workshop• Reviewed historical dissolved gas effects

• Characterized spill incorporating surface passage

• Presented and reviewed draft Experimental Spill Management Design.

• Evaluated four spill levels:• Biological Opinion-current• 115/120% - lowest increase• 120% Tailrace -moderate increase• 125% Tailrace - greatest increase

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Plan for measuring response to a treatment

- Treatment = increase in spill for fish passage

- Response = change in survival

- Plan = implement CSS monitoring methods

What is experimental design?

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- Large contrast (perturbation)

- High precision of measured response variable

- High degree of replication

- Minimize and account for confounding factors

Elements of “good” experimental design

Summary of 2013 Workshop

• Applied peer-reviewed models to spill levels

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Prospective tools – integrating across river and ocean conditions

• Summarize distributions relative to desired goals (e.g., population viability)

-1% 0% 1% 2% 3% 4% 5% 6%0

10

20

30

40

50

60

70

Projected SARs

Freq

uenc

y

Undesirable

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• Summarize distributions relative to desired goals (e.g., NPCC SAR goals, Recovery)

-1% 0% 1% 2% 3% 4% 5% 6%0

10

20

30

40

50

60

70

Projected SARs

Freq

uenc

y

Desirable

Prospective tools – integrating across river and ocean conditions

Probability

Chinook- Undesirable (< 1% SARS)

125 120 115/120 BIOP0%

25%

50%

75%

100%

Spill Treatment 28

60%Since ‘98: 65%

Probability

Chinook- Desirable (> 2% SARS)

Spill Treatment

125 120 115/120 BIOP0%

25%

50%

75%

100%

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14%Since ‘98: 10%

Summary of 2013Workshop

• Applied peer-reviewed models to spill levels

Summary of 2013Workshop

• Applied peer-reviewed models to spill levels

125% 120% 115/120% BiOp Observed0

1

2

3

4Steelhead

125% 120% 115/120% BiOp Observed0

1

2

3

4Chinook salmon

SAR

Summary:• Definition of spill scenarios for simulations based on what appears

technically possible with current FCRPS configuration

• Biological Planning tool indicates 125% spill level most likely to achieve SAR objectives

• Ongoing CSS analyses provide rigorous monitoring framework to evaluate Experimental Spill Management

• Expected benefits to Upper- & Mid-Columbia stocks – These stocks provide for additional monitoring/learning

• Simulations are encouraging in terms of:– expected response (conservation benefit)– likelihood of detecting response (learning)

Questions?