National Guidelines For Water Quality

http://www.dpipwe.tas.gov.au/inter.nsf/WebPages/JMUY-52B3YX?

Tasmanian Guidelines

Microbiological Guidelines

DPIPWE site-specific trigger values

Further Information

Australian Water Quality Guidelines

As part of a National strategy to ‘pursue the sustainable use of the nation’s water resources by protecting and enhancing their quality while maintaining economic and social development’ the Australian and New Zealand Environment and Conservation Council (ANZECC) has developed water quality guidelines (numerical concentration limits or descriptive statements) for a range of ecosystem types, water uses (environmental values) and water quality indicators. Titled 'Australian and New Zealand Guidelines for Fresh and Marine Water Quality' this document is available for use as a reference tool for catchment management plans and policies.

The current ANZECC 2000 guidelines suggest a ‘risk assessment’ approach which utilises the concept of increased risk with increasing departure from ‘safe’ levels. It also states the principle that they are simply guidelines to be used in the absence of local reference data, and that where local data can be obtained, they should be used to develop local water quality standards.

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ANZECC water quality guidelines for Tasmania

Where there is insufficient reference data available to develop locally relevant guidelines, the ANZECC 2000 guidelines provide regional default low-risk trigger values for a range of physical and chemical water quality parameters in slightly to moderately disturbed ecosystems. These low-risk trigger values may be used for the purpose of protecting aquatic ecosystem health, and set limits (or ranges) below (or within) which there is a low risk of adverse ecological effects. The default trigger values for rivers in south east Australia (including Tasmania) are classified into two categories, based on altitude: lowland rivers (below 150m) and upland rivers (above 150m).

ANZECC default low-risk trigger values for nutrients, pH and DO

Ecosystem Type TP

(g/L) FRP-P

(g/L) TN

(g/L) NOx-N

(g/L) NH4+ - N

(g/L) pH * DO (%sat)

Lowland River 50 20 500 190 20 6.5 - 8.0 85 - 110

Upland River 13 5 480 190 135 6.5 - 7.5 90 - 110

Lakes and Reservoirs 10 5 350 10 10 6.5 - 8.0 90 - 110

*pH trigger values for humic rich Tasmanian rivers are 4.0 - 6.5

ANZECC default low-risk trigger values for salinity (measured as conductivity)

Ecosystem type Conductivity (S/cm) Explanatory notes

Lowland Rivers 125-2200 Lowland rivers may have higher conductivity during low flow periods with saline surface water and groundwater inputs. Low values are found in eastern highlands of Victoria (125 Scm-1) and higher values in western lowlands and northern plains of Victoria (2200 Scm-1). NSW coastal rivers are typically in the range 200 - 300 Scm-1.

Upland Rivers 30–350 Conductivity in upland streams will vary depending upon catchment geology. Low values found in Vic alpine regions (30 Scm-1) and eastern highlands (55 Scm-1), high value (350 Scm-1) in NSW rivers. Tasmanian rivers mid-range (90 Scm-1).

Lakes/ Reservoirs 20–30 Conductivity in lakes and reservoirs are generally low, but will vary depending upon catchment geology. Values provided are typical of Tasmanian lakes and reservoirs.

ANZECC default low-risk trigger values for turbidity

Ecosystem type Turbidity (NTU) Explanatory notes

Lowland Rivers 6-50 Turbidity in lowland rivers can be extremely variable. Values at the low end of the range would be round in rivers flowing through well-vegetated catchments and at low flows. Values at the high end of the range would be found in rivers draining slightly disturbed catchments and in many rivers at high flows.

Upland Rivers 2–25 Most good condition upland streams have low turbidity. High values may be observed during high flow events.

Lakes & Reservoirs 1–20 Most deep lakes and reservoirs have low turbidity. However shallow lakes and reservoirs may have higher natural turbidity due to wind-induced resuspension of sediments. Lakes and reservoirs in catchment with highly dispersable soils will have high turbidity.

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