Christopher BobbiDPIPWE T i AUSTRALIADPIPWE, Tasmania AUSTRALIA

Tasmanian Environmental Flows Framework (2007)

fi i l bj i1. Define environmental objectives

2. Conduct field assessments and hydraulic modellingy g

3. Conduct hydrological analyses and define flow characteristics that meet objectivescharacteristics that meet objectives

– Where these are not known, use the natural flow regime as a guide (Poff et al 1997)regime as a guide (Poff et al., 1997)

4. Recommend holistic environmental flows            (f i d i )(for rivers and estuaries)

Framework assumptionsp

NATURAL FLOW VARIABILITY

PHYSICAL HETEROGENEITYVARIABILITY HETEROGENEITY

BIODIVERSITY &ECOSYSTEM PROCESSES

Walker et al., 1995. Regulated Rivers: Research & Management 11:85.Poff et al., 1997. Bioscience 47:769.

Ward et al., 2001. Regulated Rivers: Research & Management 17:311.

Project approach

Stage 1: Scoping

j pp

Jul 06 ‐ Feb 07Stage 1: Scoping‐ Biophysical characterisation

D l t f t l d l d h th

Jul 06  Feb 07

‐ Development of conceptual models and hypotheses

‐ Site selection and methodologies 

Stage 2: Scientific studies Feb 07 ‐ Jan 09

Stage 3: Understanding linkagesJ 09 D 09Jan 09 ‐ Dec 09

www.dpipwe.tas.gov.au/Report Title: Tasmanian Environmental Flows (TEFlows) Project

TEFlows Project catchmentsj

Low flow variability (LV rivers)Photo: Jenny Davis

Ringarooma River (and estuary)

Great Forester River

Dans Rivulet

Littl S t Ri ( d t )

High flow variability (HV rivers)Photo: Jeff Ross

Little Swanport River (and estuary)

Macquarie River

Brushy Plains Rivulet

0 40 80 120 160 Kilometers

Conceptual modelspHypotheses: influence of flow regime variability on ecosystem components:ecosystem components:

• Physical habitat (e.g. woody debris and sediments)

A i d i i i• Aquatic and riparian vegetation

• Food webs

• Ecosystem metabolism

LV rivers HV riversLV rivers

Ringarooma Little SwanportResults: Hydrology(LV river)

406 815

(HV river)

58 035Mean annual runoff (ML) 406,81512.9

0

58,0352.822

Mean annual runoff (ML)Mean daily flow (m3s‐1)Mean number zero flow (days/yr) 0

1.2622

3.72( y /y )

Mean annual CVColwells indices:

0.4590.2540 205

0.1580.0560 102

PredictabilityConstancyContingency 0.205 0.102Contingency

Results: Physical structure

HV rivers:   Poorly sorted, physical attributes change over short Brushy Plains Rivulet

y , p y gdistances, low angle banks

Great Forester RiverLV rivers:    Well sorted, sediment frequently mobilised, high bank 

angle, dense vegetation encroachment

Results: Leaf litter

DryWet

Low variability

5

DryWet

High variability

5

LV river HV river

face

are

a (%

)

3

4

face

are

a (%

)

3

4S

urf

0

1

2 Sur

f

0

1

2

Autumn Spring

0

Autumn Spring

0

150 0.06 .06 .06

30 0.05 .05 .05

Great Forester River (GF2) Transect #2 Little Swanport River (LS1) Transect #6

148.5

149.0

149.5

150.0

Elev

atio

n (m

)

28.5

29.0

29.5

30.0

Elev

atio

n (m

)

0 5 10 15 20147.5

148.0

Station (m)

E

0 10 20 30 40 5027.5

28.0

Station (m)

E

Results: Terrestrial carbon use

80.0%90.0%

100.0%

Brushy Plains Rivulet Site 1%)

Brushy Plains Rivulet Site 1 Densiometercover = 21%

30 0%40.0%50.0%60.0%70.0%

carbon

 (%

cover   21%

0.0%10.0%20.0%30.0%

Apr-07 Aug-07 Nov-07 Feb-08 Jun-08 Sep-08 Dec-08restrial c

80.0%90.0%

100.0%Brushy Plains Rivulet Site 2

on of ter Brushy Plains Rivulet Site 2 Densiometer

cover = 43%

30 0%40.0%50.0%60.0%70.0%

ontributio cover   43%

0.0%10.0%20.0%30.0%

Apr-07 Aug-07 Nov-07 Feb-08 Jun-08 Sep-08 Dec-08

Co

Results: Macroinvertebrates

2.0RR1Au08

Riffle habitat communitiesSignificant variables:

1.5

1

sg

GF1Sp07

GF1Wi07GF2Wi07

RR1Au08g

‐ Flow type (HV or LV)‐ % fine sediments

0.5

1.0

CA

P2 silt

flowTypelowrsff

BP2Wi08

LS1Wi08

LS2Wi07GF1Au08

GF1Sp07

GF2Su08

% e sed e ts‐ Flow peakiness‐ River size flow features

-0.5

0.0

C

0

fines

BP2Wi08

LS1Au07

DR1Su08

DR1Wi08

DR2A 08

-1.5

-1.0peaky

LS1Au07

MR2Au07MR2Wi07

DR2Au08

DR2Sp07

DR2Sp08

DR2Su08

DR2Wi08

-1 0 1 2

CAP1

d iRed = HV riversBlue = LV rivers

Results: Estuarine food web

16Little Swanport • Stable isotope analysis

• Pooled bi‐plots of δ13C and δ15N Little Swanport Estuary (HV river)

121

42 3

signatures for estuarine food webs

SPOMEpiphytes

8

dN15

5

76

10

9

8

11 16RingaroomaRingarooma Estuary (LV river)

Seagrass

Sediment

Epiphytes

Dead seagrass

0

4

1212

34

SPOMSediment

-28 -24 -20 -16 -12 -8dC13

0

8

dN15

5

67

89

11

Sediment

SPOM

Dead seagrass

4

10

SPOMSediment

‐ Fish

‐ Crustaceansseagrass

-28 -24 -20 -16 -12 -8dC13

0‐Molluscs

Results: Estuarine response to flow eventsLittle Swanport Estuary (HV river)

600

800

ML

day-1

)6

l t

River flow

Chlorophyll a

0

200

400

Riv

er F

low

(M

3

4

5

phyl

l a (u

g l-1

)

lower estuarymiddle estuaryupper estuary

Chlorophyll a

0.012

9-S

ep-0

8

23-S

ep-0

8

21-O

ct-0

8

3-N

ov-0

8

21-N

ov-0

8

2-D

ec-0

8

15-D

ec-0

822

-Dec

-08

30-D

ec-0

85-

Jan-

0912

-Jan

-09

20-J

an-0

927

-Jan

-09

10-F

eb-0

9

24-F

eb-0

9

11-M

ar-0

9

24-M

ar-0

9

7-A

pr-0

9

21-A

pr-0

9

p-08

p-08 t-0

8

v-08

v-08

c-08

c-08

c-08

c-08 -0

9-0

9-0

9-0

9

b-09

b-09 r-0

9

r-09

r-09

r-09

0

1

2

Chl

orop

PO4

0.004

0.008

PO4

(mg

l-1)

9-S

ep

23-S

ep

21-O

ct

3-N

ov

21-N

ov

2-D

ec

15-D

ec22

-Dec

30-D

ec5-

Jan

12-J

an20

-Jan

27-J

an

10-F

eb

24-F

eb

11-M

ar

24-M

ar

7-Ap

r

21-A

pr

40

ml-1

) Dinoflagellates

0.4

0.6

1 )

lower estuarymiddle estuaryupper estuary

0

10

20

30

agel

late

abu

ndan

ce (m

NOx

0.2NO

x (m

g l-1

-20 0 20 40 60

0

Din

ofla

0

How does this help us make better water pmanagement decisions?1. In eastern Tasmania, the two different flow types DO produce ecosystems of differing character.

2. Confirms (at a local scale) theories about links between hydrological variability, physical habitat y g y, p ycomplexity and biological diversity.

3 Id ifi fl i (3. Identifies flow regime components (e.g. cease‐to‐flow events, seasonal floods, seasonal baseflow) h b i i l h ithat may be critical to the environment.

How does this help us make better water pmanagement decisions?4. Better predictions of the impacts of water management strategies on aquatic ecosystems of these river types.

5 Estuarine ecosystems are influenced by FW inflows5. Estuarine ecosystems are influenced by FW inflows and geomorphology. Despite being highly flexible, the timing and magnitude of inflows can be highlythe timing and magnitude of inflows can be highly influential.

AcknowledgementsAcknowledgementsDPIPWE:

Lead researcher:  Adam Uytendaal

Danielle Warfe, (now Charles Darwin University), Scott Hardie, Mike Male, Greg McDonald,  Kate Hoyle, David Horner, Tom Krasnicki, David Spiers,  John Gooderham, Shivaraj Gurung, Danielle Hardie, Justine Latton, MartinJohn Gooderham,  Shivaraj Gurung,  Danielle Hardie,  Justine Latton, Martin Read, and Bryce Graham.

Contributing consults:gLeon Barmuta and Anne Watson (University of Tasmania),  Jeff Ross  and Christine Crawford (Tasmanian Aquaculture and Fisheries Institute), Janet Smith, Peter Davies (Freshwater Systems),  Lois Koehnken (Technical Advice on Water) and Glen McPherson (Glen McPherson Consultancy).

Scientific Review Panel:Angela Arthington, Margaret Brock, Peter M. Davies, Graham Harris, Sam Lake, Helen Locher, Paul Reich, Peter Scanes and John Whittington.

Project website:Project website: 

www.dpiw.tas.gov.au/teflows