Comparative Survival Study Outcomes –
Experimental Spill Management
Howard Schaller
PSMFC Annual Meeting
September 24, 2013
1
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
History and Background
• Analyzed multiple lines of evidence
• 60- 40 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
• Developed spill scenarios on the basis
COE data
3
NPCC Smolt-to-Adult Survival GoalRecovery
• Achieve SARs averaging 4% for Snake River
Chinook salmon and steelhead
4
3
SAR
2
1
0
Chinook
Observed
Steelhead
Observed
NPCC Smolt-to-Adult Survival GoalRecovery
• Achieve SARs averaging 4% for Snake River
Chinook salmon and steelhead
4
3
SAR
2
1
0
Chinook
Observed
Steelhead
Observed
Decline in Snake R. Chinook & steelhead
associated with dams…
3
4 5 6 7 8 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
7
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.”
8
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
Approach
Weight of evidence Multiple lines of evidence for relative importance of major
factors influencing survival rates
Precision & Specificity
Life
stage
CSS SARs (Chin & Sthd)
SARs (run rec. - Snake Chin & Sthd)
Life
cycle
Spawner:recruit (Snake & John Day Chin)
3
1960
4 5 6
1965
7
1970
8dams
1975
1980
1985
1990
Environmental Contrast
1995
2000
2005
2010
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
• Over a dozen peer reviewed publications
Relative Variable Importance
Steelhead
5%
4%
SAR
3%
2%
1%
0%
1997
1999
2001
2003
2005
2007
2009
Chinook
4%
3%
SAR
2%
1%
0%
1997
1999
2001
2003
2005
2007
2009
Relative Variable Importance
Steelhead
5%
SAR
1.0
4%
0.8
3%
0.6
2%
0.4
1%
0.2
0%
1997
0.0
1999
2001
2003
2005
2007
2009
Chinook
4%
Day
-
N.Spill
+
WTT
-
Screens
+
PDO
-
1.0
0.8
3%
SAR
0.6
2%
0.4
1%
0%
1997
0.2
0.0
1999
2001
2003
2005
2007
2009
Day
-
N.Spill
+
WTT
-
Screens
+
PDO
-
In-river Passage Routes
Non-powerhouse = Spill (traditional or surface spillway weirs)
Powerhouse = Turbine or juvenile collection/bypass
Direct survival:
spill > bypass > turbine
(1) Spillway
Reservoir
Forebay
Gatewell
Direct & indirect survival
(delayed mortality):
spill > bypass
spill > turbine
Forebay & Tailrace
TDG monitoring
Collection channel
Tailrace
(2) Juvenile Bypass Systems
Submersible traveling screen
(3) Turbine
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 approachsupported by empirical observations:
– Juvenile survival
– SARs
– TDG effects
Variability of Spill 1995-2012
5
Summary of GBT Samples (1995-2012)
as a function of TDG
Percent of Fish with Fin GBT
25%
PctFinGBT
PctRank1
PctRank2
PctRank3
PctRank4
20%
15%
223,921 fish examined
10%
7.7%
4.9%
5%
2.5%
0%
0.2%
100 to 105
0.3%
106 to 110
0.9%
0.6%
111 to 115
116 to 120
121 to 125
126 to 130
Upstream Tailwater TDGS
130 to 139
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.
2
Summary of 2013 Workshop
• Reviewed historical dissolved gas effects.
•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
What is experimental design?
Plan for measuring response to a treatment
- Treatment = increase in spill for fish passage
- Response = change in survival
- Plan = implement CSS monitoring methods
21
Elements of “good” experimental design
- Large contrast (perturbation)
- High precision of measured response variable
- High degree of replication
- Minimize and account for confounding factors
22
Summary of 2013Workshop
• Applied peer-reviewed models to spill levels
Prospective tools –
integrating across river and ocean conditions
• Summarize distributions relative to desired goals (e.g.,
population viability)
Undesirable
70
Frequency
60
50
40
30
20
10
0
0%
1%
2%
3%
4%
Projected SARs
5%
6%
24
Prospective tools –
integrating across river and ocean conditions
• Summarize distributions relative to desired goals (e.g.,
NPCC SAR goals, Recovery)
Desirable
70
Frequency
60
50
40
30
20
10
0
0%
1%
2%
3%
4%
Projected SARs
5%
6%
25
Chinook- Undesirable (< 1% SARS)
100%
Since ‘98: 65%
75%
60%
Probability
50%
25%
0%
125
120
115/120
BIOP
Spill Treatment
26
Chinook- Desirable (> 2% SARS)
100%
75%
Probability
50%
Since ‘98: 10%
14%
25%
0%
125
120
115/120
BIOP
Spill Treatment
27
Summary of 2013Workshop
• Applied peer-reviewed models to spill levels
Chinook salmon
SAR
Steelhead
4
4
3
3
2
2
1
1
0
0
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
• 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?