Environmental flows: aconundrum.

Peter B. Moyle*, Joseph D. Kiernan, and John G. Williams

Center for Watershed Sciences, University of California, Davis.

“IMPROVING ENVIRONMENTAL FLOW METHODOLOGIES USED IN CALIFORNIA FERC

RELICENSING”

Dams in California• 1400 “jurisdictional” dams• 1000’s of smaller dams• 212 dams being relicensed by FERC

– 51 projects,1993-2010

Martis Creek 2009

Jurisdictional vsNon-jurisdictionaldams

Environmental Flow Approaches“Bottom up” vs “top down”

• “Bottom up”– What is the minimum amount of water needed

to keep target species going– Hydrology or habitat based methodologies

“Top down”How much water does the ecosystem need to keep functioning?Holistic or expert based methodologies

An oversimplified classification of methodologies

• Hydrology based– Tennant– Range of Variation (ROV)

• Habitat based– PHABSIM– Individual based models (IBM)

• Expert based– Demonstration flow assessment (DFA)– Non-quantitative

• Holistic

Difficulty

Tennant

ROV

Holistic

Habitat simulation

IBM

Expert Opinion

Realism:likelihood predictions will matchwith realityin long run

Expert

DFA

hydrologichabitat

Likely water/power yield

Tennant

ROV

Holistic

Habitat simulation

IBMProbabilitythat desired ecosystem values will persist

high

low

DFA

Expert opinion

Expert

HydrologicHabitat

Our Basic Findings• Regulated streams can be managed to favor desired

fishes (PM)• EFMs used in California are seriously flawed, esp.

statistical foundations (JW)• Bayesian Networks seem a better alternative; more

effective and likely less costly (JW)– More compatible with adaptive management

• Fish assemblages have a complex relationship to flows (JK)

• Monitoring for FERC projects is inadequate (JK)• May lead to erroneous conclusions about effects on fish

DAM NEAR TRUCKEE IS HIGH RISKPage 1,Sacramento Bee, December 5,2010

MARTIS CREEK DAM

1980 1985 1990 1995 2000 2005

Mea

n A

nnua

l Dis

char

ge (c

fs)

0

20

40

60

80Wet YearNormal YearDry Year

Median

25th Percentile

75th Percentile

Martis Creekmean annual discharge 1979-2008

1991

1992

1993

1994

1995

19

96

1997

19

98

1999

20

00

2001

20

02

2003

2004

2005

2006

20

07

2008

Mea

n da

ily d

isch

arge

(m3 /s

)

0.1

1

10

100

Mean daily discharge from the Putah Diversion Dam during the period of study, 1991-2008

Dis

char

ge (m

3 /s)

0.1

1

10

100

1000

Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep

B.

Summary of Putah Diversion Dam discharge for each day of the water year based on the complete period of record (N = 31 years): blue line = mean discharge, gray shaded region = range of discharge values.

Putah Creek is a refuge for native fishes

Sacramento pikeminnow

Threespine stickleback

Hitch

Tule perch

Anadromous fish spawn in Putah Creek

Spawning Pacific lampreyJuan Cervantes

Spawning chinook salmonJuvenile chinook salmon,Putah Creek

Alien fishes

Green sunfish

Bluegill

Largemouth bass

Putah Cr above Pedrick Road

Settlement, 2000Putah Creek Council et al. vs. Solano Water Agency

• Water for creek• Money for monitoring• Stream keeper• Putah Creek Coordinating Council• Drought protection for Solano County

Pro

porti

on n

ativ

e s

peci

es (a

bund

ance

)

0.0

0.2

0.4

0.6

0.8

1.0

1990 1995 2000 20050.0

0.2

0.4

0.6

0.8

1.0

1990 1995 2000 2005 1990 1995 2000 20050.0

0.2

0.4

0.6

0.8

1.0

Pro

porti

on n

ativ

e sp

ecie

s (a

bund

ance

)

0.0

0.2

0.4

0.6

0.8

1.0

1990 1995 2000 20050.0

0.2

0.4

0.6

0.8

1.0

1990 1995 2000 20050.0

0.2

0.4

0.6

0.8

1.0

1990 1995 2000 2005

A

A

B

B

C

C

D E F

D E F

Relationship between mean spring (1 March through 30 May) discharge and the proportion of the total fish assemblage comprised of native species at each sample site.

A)

0.0

0.2

0.4

0.6

0.8

1.0 B)

0.0

0.2

0.4

0.6

0.8

1.0 C)

Prop

ortio

n na

tive

spec

ies

0.0

0.2

0.4

0.6

0.8

1.0

D)

0.0 0.5 1.0 1.5 2.00.0

0.2

0.4

0.6

0.8

1.0

0.0 0.5 1.0 1.5 2.00.0

0.2

0.40.8

1.0E)

Mean spring discharge (log10 m3/s + 1)0.0 0.5 1.0 1.5 2.0

0.0

0.2

0.40.8

1.0 F)

r2= 0.00P = 0.98

r2= 0.17P = 0.09

r2= 0.30P = 0.02

r2= 0.36P < 0.01

r2= 0.00P = 0.77

r2= 0.18P = 0.28

-1 0 1

-1

0

1

LEPCRP SP

DRBT

RSC

LEPCCFLMBIS P

OM

nMDS 1

-1 0 1

nMD

S 2

-1

0

1

LEPFHM

CCFBGS

ISS

DI

SP

O

M

Pre-Accord Post-AccordSBK

PSC

RCHHTC

SKRPKMPLR

TUP

SMB CRPSBF

FHMMSQISS

GLF BBH

BGSGSF

BLPWCF

BCR

WRMRSH

RES

RBTSBK

RCHPSC

HTCTUP

RSCPLR

SKRPKM

SMB

LMBCRP

BLP

MSQGSF

BBH

WRMGLF

SBFRES WCF

RSH

BCR

Non-metric multidimensional scaling ordinations of the lower Putah Creek fish assemblages at six sites before (A) and after (B) alteration of the flow regime. Native species are shown in blue. Shaded ellipses represent the 95% confidence interval surrounding the mean position of each sample site in ordination space.

0

10

20

30

40

50

60

70

80

90

Alien Native Alien Native

1991-1998 1998-2008

Perc

enta

gePercent alien and native fish numbers before and after establishment of a 'natural' flow regime, Putah Creek

Stevenson Road station

BEFORE AFTER

EFFECTS ON NATIVE FISH ABUNDANCE: ESTABLISHING A ‘NATURAL’ FLOW REGIME

1991-97N= 7

1998-2008N= 10

Key Points

•Goal was clearly stated•Expand native fish assemblage

•Shift in fish assemblage happened in response to shift in flow regime

•Spring flows important for native fishes

•Water cost low •Assemblage has ‘memory’ of past events, so some resetting was probably needed.•Habitat major component of success

Making the changes permanent

• Habitat restoration• Community involvement

– Putah Creek source of pride– Other ecosystem benefits

• Water Agency involvement– Solano Water Agency– Stream Keeper

• Monitoring

Conclusions

• Many different methodologies• Important to have clear goals for flows• Putah Creek demonstrates possible to

successfully manipulate flows to achieve goals, based on expert opinion

• Dueling expert opinions likely to be settled in court