Digital Map fromDr. William Bowen California State University Northridge

Sacramento-San Joaquin

DeltaSan Joaquin

River

Sacramento River

Suisun Bay

San Francisco

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2

Stationary Habitat ---Geometry

Dynamic Habitat ---Hydrodynamics, ocean conditions, weather

Environment

Biological Conditions

3

Estuarine habitat conceptual model(Peterson 2003)

Stationary Habitat

Dynamic Habitat

Production AreaTidal and River Flow

PelagicRecruitment

4

Hydrology

Delta Geometry

Water Demand

Exports

Delta Hydrodynamics

Realized Habitat

Potential Habitat

Biological and Chemical Conditions

5

Tides

0 50 100 150 200 250 300 3500

0

5

10

15

O N D J F M A M J J A S

Day of Water Year

W D

1983 1977 1998 1991 1995 1992 1982 1990 1958 1994 (1997)

Dry Years

Wet Years

Fre

shw

ater

Flo

w (

m3 s

-1)

Variability of Freshwater Delta Inflow

6

X2=

82

X2=

70

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Pelagic organisms follow salinity:The copepod Eurytemora affinis

Kimmerer 1998

40 50 60 70 80 90 10040

50

60

70

80

90

100

110

1:1 Regression Line

X2 (km)

Po

sit

ion

of

Pe

ak

(k

m)

8X2 (km)

1009080706050

100

90

80

70

60

50

X2

Cen

ter

of d

istr

ibut

ion

1:1

Pelagic organisms follow salinity: Delta smelt

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0 10 20 300

20

40

60

80

100Delta smelt

Thr. shadAm. shad

Striped bass

Chinook salmon

Salinity

C

um

ula

tive

Pe

rce

nt

Splittail

Most fishes follow salinities

Kimmerer 2004

Marine species

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1967-871988-2000

1982-2000 (DS)All Years

1

2

3

4

1

2

3

4

0

1

2

3

2

3

4

5

0

1

2

3

2

3

4

5

50 60 70 80 90

0

1

2

3

50 60 70 80 90

-2

-1

0

1

Bay Shrimp

Striped BassSplittail

Longfin smeltDelta smelt

Herring Am. Shad

Flounder

Lo

g A

bu

nd

an

ce

or

Su

rviv

al

X2 (km)High Flow Low Flow

Source:Kimmerer 2002MEPS

Higher trophic levels show many

relationships of abundance to

freshwater flow

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X2 (km)

0

1

2

0

1

2

1

2

3

4

1

2

3

4

50 60 70 80 90

2

3

4

5

50 60 70 80 90-2

-1

0

1

2

Mysid

Copepod: Spring

Copepod: Summer

Rotifer: Summer

Chlorophyll: SummerChlorophyll: Spring

Lo

g A

bu

nd

an

ce

X2(km)

High Flow Low Flow

Lower trophic levels show few relationships

of abundance to freshwater flow

Source:Kimmerer 2002 MEPS

1972-19871988-2000

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X2 (km)

1873 Delta:

Long residence time

Marsh connections

Two rivers connect to bay

Waterways dendritic

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Modern delta

Short residence times

Rip-rapped

Cross Delta flows

Rare San Joaquin connection to bay

Waterways web-like14

What Changes As Flow Increases?

X2Location of Any Salinity

RangeLSZ

Salinity and X2

FLOW

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stratification

Flo

odpl

ains

ProportionDiverted

What Changes As Flow Increases?

DeltaResidence Time

RiverStage,

Velocity

River stage and velocity

Floodplain inundation

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FLOW

FLOW

Upstream bottom current

NutrientsContaminantsOrganic matter

Sediment

What Changes As Flow Increases?

Concentrations

Loadings

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FLOW

FLOW

What Changes As Flow Increases?

Adult spawners move up:SalmonGreen and White

SturgeonLongfin smeltDelta smeltSplittailAmerican shadPacific herring

Young Marine fish move up:Starry flounderWhite croakerPacific halibut

Young fish move down:SalmonLongfin smeltDelta smeltSplittailAmerican shadStriped bass

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Flows are important but so is geometry

1.1. Environmental flows are more than just volumes of inflows Environmental flows are more than just volumes of inflows and outflowsand outflows

2.2. Recent flow regimes both harm native species and Recent flow regimes both harm native species and encourage non-native speciesencourage non-native species

3.3. Flow is a major determinant of habitat and transportFlow is a major determinant of habitat and transport

4.4. Recent Delta environmental flows are insufficient to support Recent Delta environmental flows are insufficient to support native Delta fishes for today’s habitatsnative Delta fishes for today’s habitats

5.5. A strong science program and a flexible management A strong science program and a flexible management regime are essential to improving flow criteriaregime are essential to improving flow criteria

Five Key Points

20

+

-

NutrientsOrganic matter

SedimentFish

Flo

odpl

ains

ProportionDiverted

What Changes As Flow Increases?

X2

-Delta

Residence Time

-

RiverStage,

Velocity

+

Location of Any Salinity

Range

-SalinityAt a Point

LSZ

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Delta smelt habitat abundance in relation to X2

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FishProduction

BenthicProduction

Zooplankton Production

MicrobialProduction

PhytoplanktonProduction

Nutrient Input

Organic InputInputs

Hydrodynamic Forcing:

Freshwater inflowOceanic variability

Wind

Stratification

Transport/Retention

PhysicalHabitat

Physical forcing

mechanisms

Material flows

Direct physical

influences

Key feedback

loop

Conceptual Model:Physical effects on estuarine ecosystem

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How much water do fish need?

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