Resizing a river Resizing a river : using experimental management : using experimental management to develop a downscaled environmental flow to develop a downscaled environmental flow
regime for the Lower Bridge Riverregime for the Lower Bridge Riverregime for the Lower Bridge Riverregime for the Lower Bridge Riveroror
DoesDoes more water mean more fish?more water mean more fish?Does Does more water mean more fish?more water mean more fish?
Mike BradfordMike Bradford
Paul Higgins
Josh Korman
Alternative Perspectives on Alternative Perspectives on Flow Flow M tM tManagement: Management:
Natural Flow ParadigmNatural Flow Paradigm “Nature knows best”“Nature knows best”
Designer FlowsDesigner Flows Flows for target species Flows for target species
Flows for ecosystem Flows for ecosystem healthhealth
or management goalsor management goals River resizingRiver resizing
The magnitude of the The magnitude of the impact is related to the impact is related to the “degree of hydrologic“degree of hydrologic
More water ≠ more fish More water ≠ more fish degree of hydrologic degree of hydrologic
alteration”alteration” More water = more fishMore water = more fish
Experimental Management as a Experimental Management as a p gp gmanagement paradigmmanagement paradigm
Substantial uncertainty in instream flow Substantial uncertainty in instream flow methodologies, most are not testedmethodologies, most are not tested
Variable and unpredictable responses of the Variable and unpredictable responses of the ecosystem to flow changesecosystem to flow changes
Instead of flow modelling, empirically determine Instead of flow modelling, empirically determine response of the river to flow by testing a range of response of the river to flow by testing a range of flow regimes flow regimes
Bridge River, southwestern BC
Present location of Terzaghi Dam
MAD ~100 m3s
Fish production in tributaries
Terzaghi Dam, ca 1958g ,
Antoine Creek
30.4 km
26.4 km
23.6 km
20 km
Reach 2Reach 3
Michelmoon Creek
36.5 km
33.3 km
Reach 1Yankee Creek
Hell Creek
Camoo CreekTerzaghi
D
R4 MAD = 0cms
R3 MAD ~ 0.6 cms36.5 km
39.5 km
Reach 4
Mission CreekDam
CarpenterReservoir
R2 MAD ~ 5.6 cms
100% diversion for power
Terzaghi DamReach 4
Reach 2Reach 3
Mid 1990s: the reintroduction of flow Mid 1990s: the reintroduction of flow d 990 odu o o od 990 odu o o ofrom from TerzaghiTerzaghi DamDam
Modification of the damModification of the dam How much water to How much water to
release?release? Water is worth 2Water is worth 2--3 M$ per 3 M$ per
annualized mannualized m33/s for power /s for power generationgeneration
At the time, juvenile salmon At the time, juvenile salmon were the primary were the primary environmental performanceenvironmental performanceenvironmental performance environmental performance measuremeasure
Standard physical Standard physical habitat simulation in habitat simulation in Reach 3 predicted Reach 3 predicted that a large flow that a large flow release would reducerelease would reduce 0 4
0.5
release would reduce release would reduce juvenile fish habitatjuvenile fish habitat
0.3
0.4ParrParr
FFUW
)This is counter to
S lh d
0.1
0.2 FryFry
P(W
Ustandard setting approaches used by agencies
Steelhead0.00 4 8 12 16 20
River discharge (cms)
More water ≠ more fish! Prediction: Optimal flows at Prediction: Optimal flows at 11 33 cmscms (1(1 3%3% MAD)MAD)11--3 3 cmscms (1(1--3% 3% MAD)MAD)
A flow experiment was recommended to A flow experiment was recommended to arbitrate between competing hypothesesarbitrate between competing hypothesesarbitrate between competing hypothesesarbitrate between competing hypotheses
HH11: : “More flow “More flow produces more fish”produces more fish” 75produces more fishproduces more fish
Fish production Fish production is direct is direct function of the relationship function of the relationship between wetted area and between wetted area and flfl
50('000
)
flowflow
25
Smol
ts
HH22: : “More flow will not “More flow will not produce more fish”produce more fish”
Habitat quality changes with Habitat quality changes with
00 1 2 3 4 5
Ri Di h ( )q y gq y gflow, and after some flow, and after some threshold point this causes threshold point this causes a net reduction in fish a net reduction in fish production production
River Discharge (cms)
pp
Recommended planned flow 12
14
16
s)
3 cms WUP6 cms WUP6 cms modified
planned flow treatments:
6
8
10
Rel
ease
(cm
Seasonal flow variation “semi- 2
4
6
Dam
natural flow”
4-year 7ud
get
0
Jan
Feb
Mar Apr
May Ju
nJu
l
Aug
Sep Oct
Nov
Dec
4-year treatment blocks 4
5
6
se W
ater
Bu
/y)
PlannedRealized
blocks
1
2
3
Dam
Rel
eas
(cm
s
0
1
1996
1998
2000
2002
2004
2006
2008
2010
2012
2014A
nnua
l
Reintroduction of continuous flowscontinuous flows began August 1, 2000
Hall et al 2009
Before Afterch
4
Rea
ch
3R
each
Monitoring Design Monitoring Design
PrePre--release: 1996release: 1996--19991999 Release year: 2000Release year: 2000 Post release: 2001Post release: 2001--20082008 Post release: 2001Post release: 2001--20082008 Basic unitBasic unit-- 3 pass backpack E/f 3 pass backpack E/f 1212--18 sites in each of 3 reaches18 sites in each of 3 reaches Additional indicators:Additional indicators:
Fish conditionFish condition Lower Lower trophictrophic levelslevelspp Physical and chemical monitoringPhysical and chemical monitoring
Hierarchical model for analyzing electrofishing data
mr hrLoop over reaches (r)
wr r Nucr
l Nus Nss
Ntotr Ntot
lr Nusr Nssr
l ,r l ,r
ai i
lLoop over passes (j)
li ci,j
Ni,1 Ni,j Ni,j+1
Loop over sites (i)
300
All Reaches Reach 3 Age-0 rainbow
150
200
250
danc
e ('0
00s)
100
150
danc
e ('0
00s)
Median
trout
0
50
100Abu
nd
0
50Abu
nd
abundance and 95% credible
1996 2000 2004 2008
60
Reach 2
1996 2000 2004 2008
Reach 4
credible intervals of abundance by
d
40
50
60
e ('0
00s)
100
150
e ('0
00s)
year and reach.Dashed horizontal li h th
10
20
30
Abu
ndan
ce
50
100
Abu
ndan
ce lines show the average abundance pre- and post-flow release
1996 2000 2004 2008
0
1996 2000 2004 2008
0
120
All Reaches
80
Reach 3 Age-1 rainbow trout
60
80
100
danc
e ('0
00s)
40
60
danc
e ('0
00s) Median
abundance d 95%
0
20
40
Abu
nd
0
20Abu
nd and 95% credible intervals of
1996 2000 2004 2008
Reach 2
1996 2000 2004 2008
Reach 4
abundance by year and reach
10
15
e ('0
00s)
30
40
50
e ('0
00s)
reach.
Dashed horizontal lines show the
5Abu
ndan
ce
10
20
Abu
ndan
ce average abundance pre- and post-flow release
1996 2000 2004 2008
0
1996 2000 2004 2008
0
120
All Reaches
100
Reach 3 Age-0 Coho salmon
60
80
100
danc
e ('0
00s)
60
80
danc
e ('0
00s)
0
20
40
Abu
nd
0
20
40
Abu
nd
Posterior distributions of abundance of
1996 2000 2004 2008
35
Reach 2
1996 2000 2004 2008
70
Reach 4
abundance of pre- and post-flow release
20
25
30
35
e ('0
00s)
40
50
60
e ('0
00s)
5
10
15
Abu
ndan
ce
10
20
30
Abu
ndan
ce
1996 2000 2004 2008
0
1996 2000 2004 2008
0
140
All Reaches
120
Reach 3 Age-0 chinook
60
80
100
120
ance
('00
0s)
60
80
100
ance
('00
0s)
Median
salmon
0
20
40
60
Abu
nd
0
20
40Abu
nd
Median abundance and 95% credible
1996 2000 2004 2008
0
Reach 2
1996 2000 2004 2008
0
Reach 4
credible intervals of abundance by
30
40
50
e ('0
00s)
4
6
e ('0
00s)
year and reach.
10
20
30
Abu
ndan
ce
2
4
Abu
ndan
ce
1996 2000 2004 2008
0
1996 2000 2004 2008
0
Is the Is the chinookchinook salmon decline caused by the impact salmon decline caused by the impact of of the altered thermal the altered thermal regime on regime on abundance?abundance?gg
0+ Chinook0+ Chinook
Site 30.4 Mean Temperature
14
0+ Chinook abundance: decline due to change in life
0+ Chinook abundance: decline due to change in life6
8
10
12
ter T
emp
(C)
0 cms3 cms6 cms change in life
history caused by increased larval development
change in life history caused by increased larval development
0
2
4
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Wat
prates
prates
Site 30.4 Estimated Chinook Emergence Dates
0 cms3 cms
Wat
er B
udge
t 3 cmsOption 1Option 2Option 3Option 4O ti 5
3-N
ov10
-Nov
17-N
ov24
-Nov
1-D
ec8-
Dec
15-D
ec22
-Dec
29-D
ec5-
Jan
12-J
an19
-Jan
26-J
an2-
Feb
9-Fe
b16
-Feb
23-F
eb2-
Mar
9-M
ar16
-Mar
23-M
ar30
-Mar
6-A
pr13
-Apr
Est. Earliest Emergence Date
Option 5aOption 5b
Summary of change over all 4 fish taxaSummary of change over all 4 fish taxa
R tt dLittle change 3x increase Rewetted
Is habitat in the Bridge River too complex to model or predict?
What have we learned?
1. Biology
P i t th fl l th B id Ri• Prior to the flow release the Bridge River was a productive salmon river
• Increasing the flow to the wetted reach had no effect on salmon abundance- this was contrary to
di ti b d h bit t d h d lipredictions based on habitat and hydraulic modelling
•Each fish taxa responded differently
• Possible to “resize the river”- a smaller flow release would likely provide similar benefits
What have we learned, con’t2. Resource management
• The river is not a “scientist’s sandbox”s o a s s s sa dbo
• We did not capture the important values to stakeholdersstakeholders
• Esthetic and cultural values strongly support higher flowshigher flows
5
6
7
Wat
er B
udge
t
PlannedRealized
1
2
3
4
Dam
Rel
ease
W(c
ms/
y)
0
1
1996
1998
2000
2002
2004
2006
2008
2010
2012
2014An
nual
D
Is monitoring and adaptive management an Is monitoring and adaptive management an ffi i t th d f tffi i t th d f tefficient method of resource management efficient method of resource management
decision making?decision making?
Long trials are difficult to sustain in today’s world ($$, time, shifting social environment)
Key questions may be less relevant by the end Lower requirement for accurate biological
information in complex decision environments where many factors are in play.
Value of information analysis at local and regional scales
See you in 2016 for the final See you in 2016 for the final yychapter!chapter!
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