Assessing estuary pressures and the relationships with catchment conditions

Michaela Dommisse, Multi-regional projects (#203029)

Po rt P hi llip B ay

Lim eb ur ne rs Ba y

Po rt P hi llip B ay

Sk ele ton C re ek

Ko ror oit C ree k

Lav er ton C re ek

We rri be e R iv er

Port Phillip Bay

Western Port Bay

Corner Inlet

Gippsland Lakes

Swan Bay

Shallow Inlet

Lake Tyers

Anderson Inlet

Barwon River

Sydenham InletYarra River

Tamboon Inlet

Snowy River

Jack Smith Lake

Curdies Inlet

Limeburners Bay

Aire River

Hopkins RiverMoyne River

Skeleton Creek

Gellibrand River

Fitzroy River

Werribee River

Thompson Creek

Barham River

Anglesea River

Cumberland River

Patterson River

Painkalac Creek/Aireys Inlet

Wye River

100 0 100 Kilometers

N

EW

S

Estuaries and human activities

Kidneys of the sea

123 bays, inlets and estuariesLifestyle, freshwater, fertile land, fish catch and shipping

941

1718

23

Victoria in context of national landscape healthFuture population projection

N

Estimated population change 1996-2020in percent by Local Goverment Authority

-21 to -30

-11 to -20

-1 to -10

0 to 10

11 to 20

21 to 30

31 to 40

41 to 50

51 to 60

61 to 70

71 to 80

140 to 150

>10 people per km2 in catchments= muddy estuary (Edgar, 2001)

Values of estuariesRanging from

short

intermittent mouth

microtidal

open coast

sheltered embayment

macrotidal

open mouth

long

Anglesea Cardinia

500 m 500 m

The Project in a nutshell

1

2

34

5

Link whole of ecosystem pressure

to state

Incorporate into management plans

Make sure it

happens

outputs outcomes

Human activities and estuaries

Catchment use

Environmental flowCoastal development

Harvest and use

Mouth opening

Steps for science outputs

• Summarise information on estuary pressures in a GIS or tagged database - Barton PhD (31 estuaries, phyico/chem data)

• Develop conceptual models linking pressures to estuary condition (building on SERM and Ozestuaries)

• Validate methodology (in situ)• Develop Interim guidelines

Cause-effect 1

• Spatial comparison across estuaries with different catchment characteristics, mouth opening/closing regimes etc.– broad-scale correlation

• Barton PhD - EPA data– 31 estuaries ranging from degraded

(e.g. Curdies) through “pristine” (e.g. St George, Tidal Rivers)

Cause-effect 2

• Evaluate response of estuaries to specific management actions– environmental flow releases (e.g.

Coorong and Murray flows)– nutrient management schemes (e.g.

regularly monitoring algal blooms)– estuary mouths artificially opened or

closed (e.g. non-management action in Surry)

Microbial function- conditionT6 x+1 no c 20 May

Stress: 0.14

MinimallyIntermediateHighly

Stress 0.14

nMDS

EW

Em Diagram from Jan Barton (EPA, Flinders)

Low

Steps to make it happen

• Consideration in broad strategies – regional catchments strategies

(Advocacy group)

• Incorporation into existing plans and strategies as science becomes available

(agency participation) – regional river health strategies

Time frames?

Start Methods

Aug05

March06

Pressuressummary

Dec 06

Biophysicalclassification

Indicators and conceptual models

March 07

Sept 07

Dec 07

Final report

Increase the profile of Victoria’s estuaries

Nov05 Sept 07

Housing the science

April 06 Feb 07 Dec 07Nov 05

www.dse.vic.gov.au