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.
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.
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 | | | | | |
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 (mS/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
mScm-1) and higher values in western lowlands and northern plains of Victoria (2200 mScm-1). NSW coastal rivers are typically in the range 200 - 300 mScm-1. |
| Upland Rivers | 30-350 | Conductivity in upland streams will vary depending upon catchment geology. Low values found in Vic alpine regions (30
mScm-1) and eastern highlands (55 mScm-1), high value (350 mScm-1) in NSW rivers. Tasmanian rivers mid-range (90 mScm-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. |
NRE Tas site-specific trigger values
NRE Tas undertakes quarterly monitoring for physico-chemical and nutrient parameters at 52 sites as part of its Baseline Water Quality Monitoring Program (BWQMP). NRE Tas has developed site-specific trigger values for each of the BWQMP sites using monthly monitoring data collected from November 2003 to December 2006. A trigger value is broadly defined as a concentration that, if exceeded, alerts water managers to a potential change and thus triggers a management response.
The approach used by NRE Tas to develop these site-specific trigger values has been based on the framework provided by the ANZECC 2000 guidelines. There is however an important difference in the NRE Tas trigger-setting process, in that the data sets used to develop the site-specific trigger values reflect site condition during 2003-2006, and as such provide a benchmark for 'current status'. The primary purpose of the NRE Tas site-specific triggers is to act as 'current status' trigger values which can be compared with future monitoring data to assess for stable, improving or deteriorating water quality status at each site. The current status trigger value provides a target for the protection of existing ambient water quality at BWQMP sites, recognising that existing water quality may already be influenced by varying degrees of impact. This is distinct from the ANZECC trigger-setting process which recommends that reference condition (minimal or no impact) sites are used to derive trigger values. Under the ANZECC framework, data from reference condition sites are used to develop 'low-risk' trigger values, where a low risk of adverse ecological effects can be inferred if trigger values are not exceeded (as discussed above). A subset of BWQMP sites have been identified as representative of reference condition for their catchment, and as such NRE Tas suggests that the site-specific trigger values for these particular sites may additionally be appropriate for use as 'low-risk' trigger values.
The NRE Tas site-specific trigger values are contained in the document below. This document also details the process used by NRE Tas to develop its site-specific trigger values and provides important information regarding factors influencing their scope, interpretation and application.
Site-specific trigger values for physico-chemical indicators monitored under the DPIPWE Baseline Water Qualtiy Monitoring Program (558Kb)
ANZECC Microbiological Guidelines
Primary Contact
The median bacterial content in samples of fresh or marine waters taken over the bathing season should not exceed:
- 150 faecal coliform organisms/100 mL (minimum of five samples taken at regular intervals not exceeding one month, with four out of five samples containing less than 600 organisms/100 mL);
- 35 enterococci organisms/100 mL (maximum number in any one sample: 60-100 organisms/100 mL).
Pathogenic free-living protozoans should be absent from bodies of fresh water. (It is not necessary to analyse water for these pathogens unless the temperature is greater than 24 degrees celsius.)
Secondary Contact
The median bacterial content in fresh and marine waters should not exceed:
- 1000 faecal coliform organisms/100 mL (minimum of five samples taken at regular intervals not exceeding one month, with four out of five samples containing less than 4000 organisms/100 mL);
- 230 enterococci organisms/100 mL (maximum number in any one sample 450-700 organisms/100 mL).
Drinking Water
For drinking water, guidelines published by the National Health and Medical Research Council (NHMRC, 1996) suggest that no thermotolerant coliforms (eg
E. coli) should be present in water used for drinking.
The Tasmanian
Department of Health provides detailed information regarding water quality guidelines for drinking and recreational water.
Further Information
Water Quality Parameters