Programs

Water Quality Targets

The Tamar River estuary has Estuarine and Marine water quality targets.  have been developed in conjunction with the Water Section of Environment Protection Authority (EPA) Tasmania using water quality data from the Tamar and other similarly type estuaries in Tasmania as reference condition estuaries.

The ecosystem condition for the Tamar estuary is classified as a Slightly to Moderately Disturbed (SMD) ecosystem. The determined water quality targets are for maintaining water quality or improving water quality over time. They provide guidance when assessing water quality and identifying if systems are functioning within or outside of expected ranges.

The default values for South-East Australia for physical and chemical stressors in the Australia and New Zealand Guidelines for Fresh and Marine Water Quality (2000) are applied where insufficient local data existed to derive guideline values. Site specific data exists from several years of monthly monitoring in the Tamar and other monitoring programs around the State by the Institute of Marine and Antarctic Studies (IMAS) and CSIRO. The default national guidelines for toxicants such as metals non-metal inorganics and organics are applied to all surface waters, including fresh and marine waters unless site specific toxicity assessments have been conducted.

 

The Water Quality Targets for the Tamar estuary are summarised below:

Table A. Local water quality targets.

Parameter

Chl-a

µg/L

TP

µg P/L

TN

µg N/L

Turbidity

NTU

DO

% Sat

pH

units

Estuarine Trigger level

3.4

27.4

384

6.4

Lower- 78.2  

Upper- 102.2

Lower-  7.3

Upper- 8.2

Marine Trigger level

0.7

36

340

5.1

Lower- 91.7 

Upper- 102.2

Lower – 7.9

Upper - 8.4

 

Chl-a = chlorophyll a, TP= Total Phosphorus, TN= Total Nitrogen, NTU= Nephelometric Turbidity Units D.O=Dissolved Oxygen

Lower and upper values are 20th% ile and 80th%ile values of local data.

 

Table B Default guideline trigger values for some key metals (µg/L) for the Tamar for ecosystem protection

 

Metals  μg/L

 

Copper

 

 

Lead    

 

Zinc    

Cadmium

Aluminium

Arsenic^

ANZECC Marine Trigger level

1.3

4.4

15

0.7

6*

As (III) 2.3 As(V) 4.5

* Tamar data has been used to derive this value.

^ These guideline values are for two arsenic forms.

 

The national guidelines, including Document 4, can be found at:

      http://www.environment.gov.au/water/policy-programs/nwqms/index.html

Supported by
Tasmania - Explore the possibilitiesLaunceston City CouncilWest Tamar CouncilGeorge Town CouncilNorthern Midlands CouncilMeander Valley CouncilHydro Tasmania

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