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Manning River
Water Quality Objectives explained

| Contents | Background | Consultation | Objectives | WQOs | RFOs | Glossary | Bibliography | Map | At a Glance |

• Tailoring Water Quality Objectives to local conditions
• Downstream impacts
• Water Quality Objectives
• Aquatic ecosystems
• Visual amenity
• Secondary contact recreation
• Primary contact recreation
• Livestock water supply
• Irrigation water supply
• Homestead water supply
• Drinking water - Disinfection only, or
• Drinking water - Clarification and disinfection
• Drinking water - Groundwater
• Aquatic foods (cooked)
• Industrial water supplies

This section explains each of the eleven Water Quality Objectives (WQOs) developed for NSW rivers and estuaries, and provides guideline levels to assist water quality planning and management. Guideline levels are not provided for industrial water supplies as requirements are industry specific.

See the WQOs that apply to each part of the Manning River catchment.

Achieving each WQO will mean improving poor water quality or maintaining existing good water quality.

Objectives consist of three parts: environmental values, their indicators and their guideline levels. For example, if the objective is to protect secondary contact recreation (environmental value), we need to keep the faecal coliform levels in the water (the indicator) below a specified number or guideline level.

The objectives comprise community-based environmental values and their associated national criteria drawn from the ANZECC 2000 Guidelines. They provide the statewide context for taking this work forward into catchment action plans, regional strategies and local environmental plans. 

Tailoring Water Quality Objectives to local conditions

Local water quality varies naturally because of various factors, including the type of land the waters are draining (e.g. soils, slope), or rainfall and runoff patterns (e.g. ephemeral or permanent streams). Different land use and land management practices also affect water quality. Local WQOs must take account of these variations, particularly for the environmental value of aquatic ecosystems.

The ANZECC 2000 Guidelines move away from setting fixed single number water quality criteria, and emphasise water quality criteria that can be determined on a case by case basis, according to local environmental conditions. This is done through the use of local reference data and risk based decision frameworks — see section 2.2.1.4 Tailoring guidelines for local conditions (ANZECC 2000 Guidelines). The ANZECC 2000 Guidelines establish default trigger values that are set conservatively and can be used as a benchmark for assessing water quality. Further refinement of the trigger values may be needed to take account of local conditions, especially for aquatic ecosystems and particularly in places, or for issues, requiring priority action. This should be consistent with the approach advocated by the ANZECC 2000 Guidelines of focusing on the actual issue (or threatening process) that is a risk or potential risk to the environmental value(s). The selection of the indicator and derivation of the trigger value should trigger action or investigation before the environmental value is compromised. Trigger levels that have been locally refined must still protect the environmental value and drive local protection or improvement of water quality.

The key indicators and trigger values used here are examples of some of the indicators  listed in the ANZECC 2000 Guidelines. Key indicators for each environmental value are listed below. 

Downstream impacts

Planning and management decisions need to recognise that activities and decisions made upstream affect water quality downstream. Where this involves cumulative impacts for nutrients and sediments, the best approach may be to develop load targets for the catchment (see ANZECC 2000 Guidelines).

Water Quality Objectives

Meeting water quality levels suitable for local ecosystems is generally the basis for protecting the other environmental values, which are the uses people have for water.

Where the objective applies

• This objective applies to all natural waterways.
• High level protection of aquatic ecosystems applies to waters in and immediately upstream of national parks, nature reserves, state forests, drinking water catchments and high-conservation-value areas. This reflects their largely unmodified aquatic ecosystems, value in providing natural sources of high-quality drinking water, and high levels of recreational use.
• Even in areas greatly affected by human use, continuing improvement is needed towards healthier, more diverse aquatic ecosystems.
• Water quality in artificial watercourses (e.g. drainage channels) should ideally be adequate to protect native species that may use them, as well as being adequate for the desired human uses. However, full protection of aquatic ecosystems may not be achievable in the short-term in some artificial watercourses.
• Artificial watercourses should meet the objectives (including protection of aquatic ecosystems) applying to natural waterways at any point where water from the artificial watercourse flows into a natural waterway.

Examples of key indicators and their numerical criteria (default trigger values)

The following table includes examples of some of the key water quality indicators and related numerical criteria (default trigger values) selected from the ANZECC 2000 Guidelines, relevant to assessing and monitoring the health of aquatic ecosystems. To use and interpret these guidelines, see supporting information below and the ANZECC 2000 Guidelines. The booklet "Using the ANZECC Guidelines and Water Quality Objectives in NSW" explains key terminology and concepts used in the guidelines, in the context of NSW policy.

Supporting information

• The ANZECC 2000 Guidelines advocate a risk-based approach to water quality assessment and management. That is, the intensity of assessment of current water quality status or impacts on water quality should reflect the risk of impacts on the achievement/protection of the water quality objective.
• Trigger values are the numeric criteria that if exceeded indicate potential for harmful environmental effects to occur. The default trigger values provided in ANZECC 2000 Guidelines are essentially conservative and precautionary. If they are not exceeded, a very low risk of environmental damage can be assumed. If they are exceeded, further investigation is "triggered" for the pollutant concerned. Assessing whether the exceedance means a risk of impact to the Water Quality Objective requires site-specific investigation, using decision trees provided in the Guidelines.
• For Protection of Aquatic Ecosystems in NSW, the ANZECC 2000 Guidelines provide default trigger values for major physico-chemical stressors in Tables 3.3.2 and 3.3.3 (pages 3.3-10 & 11) and for Toxicants in Table 3.4.1 (page 3.4-5).
• Note for turbidity trigger values: In general values in the lower part of the range will be found in rivers and streams during low flows and/or in more vegetated catchments. The upper Manning has turbidity values of less than 5 NTU, which is good quality. Values in the higher part of the range will be found in rivers and streams in high flows and lower in the catchment (particularly inland catchments). For lakes and reservoirs, in general the higher values will be found in waterbodies that are shallow or in areas with dispersive soils.
• Note that pH varies naturally. Whilst 6.5-8.5 is the default trigger range, values outside this range should be investigated to assess whether they reflect natural variation. For example, some streams in sandstone areas have natural pH ranges as low as 4.5.
• The approach to protecting the aquatic ecosystem should consider the whole range of interacting factors - such as variability of water quality over time, sediment interactions, river flow, local geology, land use, the needs of sensitive habitats, and people's uses for water.
• Assessing ecosystem health also requires using a range of indicators and considering local modifying factors-such as basalt soils that result in naturally higher nutrient levels, or estuary opening patterns that affect water quality. However, information on a full range of indicators may not be available from regular monitoring.
• Although modified, many non-pristine environments contain important aquatic ecosystems. Well-functioning aquatic ecosystems also benefit people using these waters, such as by reducing blue-green algal blooms.
• Reducing diffuse pollutant loads during rainfall and runoff periods should be a key focus for improving water quality. It is also important in managing longer term impacts, such as sedimentation and polluted sediments.
• The choice of toxicant indicators for use in each management situation is related to known past or current activities. Impacts are detected by measuring water, sediment or biota. Natural sources should also be considered.
• Protecting aquatic ecosystems requires mimicking natural river flow patterns as closely as possible (see River Flow Objectives explained).

Where the objective applies

• The objective applies to all waters, particularly those used for aquatic recreation and where scenic qualities are important.

Examples of key indicators and their numerical criteria

Indicators used to assess and monitor visual amenity are summarised in the table.

Supporting information

• Visual amenity will be improved by protecting aquatic ecosystems and improving stormwater management.
• Visual amenity also needs to be protected to maintain water quality for primary and secondary contact recreation.

Where the objective applies

• This objective applies to all waters but may not be achievable for some time in some areas.
• Secondary contact recreation applies in waterways where communities do not require water quality of a level suited to primary contact recreation, or where primary contact recreation will be possible only in the future.

Examples of key indicators and their numerical criteria

Indicators used to assess and monitor water for secondary contact recreation are summarised in the table.

Where the objective applies

• This objective applies in the immediate future to waters within and immediately upstream of recognised recreation sites. For many other waters, this is a long-term objective.
• Secondary contact recreation levels should apply in areas where primary contact recreation, such as swimming, is unlikely to be achieved in the immediate future, owing to pollution.

Examples of key indicators and their numerical criteria

Indicators used to assess and monitor water for primary contact recreation are summarised in the table.

Supporting information

• Maintain water quality in all areas where water quality levels for swimming are currently achieved.
• The immediate focus should be on improving swimming water quality at recognised recreation sites, with an emphasis on meeting targets during the bathing season.
• Over the longer term, water quality will need to improve to meet swimming objectives at more locations.
• Bacterial water quality tests are used to indicate the possible presence of human pathogens. DEC considers that the use of faecal coliforms and enterococci as indicators provides a suitable expression of the disease risks presented by contaminated bathing waters and allows for international comparisons to be made. It will, however, monitor closely scientific developments in this area.
• Achieving water quality levels that are safe for swimming will also result in safer water quality for non-potable uses in homesteads.
• Note that pH in ambient waterbodies varies naturally across the landscape and with time. The goal should be to retain the natural range of pH.
• The National Health and Medical Research Council released new guidelines for recreational water quality in 2005. However, these have not yet been adopted for use in NSW. Contact Beachwatch or NSW Health public health units for current information on recommended guidelines.

Where the objective applies

• This objective applies to all surface and groundwaters used to water stock.

Examples of key indicators and their numerical criteria

Indicators used to assess and monitor water for livestock water supply are summarised in the table.

Supporting information

• Poor water quality can limit livestock productivity.
• This objective is generally attainable if aquatic ecosystems are protected.

Where the objective applies

• This objective applies to all current and potential areas of irrigated crops, both small- and large-scale.
• Local requirements for irrigation water quality, such as salinity, apply.

Examples of key indicators and their numerical criteria

Indicators used to assess and monitor water for irrigation water supply are summarised in the table.

Supporting information

• Long-term effects of irrigation with saline water on soils need to be considered.
• A major consideration for irrigation water supply is the sodium adsorption ratio (SAR), which indicates the level of excess sodium in the water. If the SAR is high, the water may have an adverse effect on soil structure, even though the total salinity of the water may be low.
• A variety of plant pathogens can be distributed by irrigation water including nematodes, fungi, viruses and bacteria. However, in the absence of sufficient data, there are no guidelines for controlling plant pathogens.

Where the objective applies

• The objective applies to all homesteads that draw water from surface and groundwaters for domestic needs, including drinking water.
• The NSW Health Department advises that water for domestic use in homesteads should comply with the Australian Drinking Water Guidelines (NHMRC & NRMMC 2004) at the point of use, regardless of source.

Examples of key indicators and their numerical criteria

Key indicators for drinking water quality at the point of use in the Australian Drinking Water Guidelines (NHMRC & NRMMC 2004) are set out below. Monitoring should also be considered for health-related parameters of local concern. Communities should refer to the Australian Drinking Water Guidelines (and updates) [www.nhmrc.gov.au/publications/synopses/eh19syn.htm] for information on additional parameters.

Supporting information

• For an individual water supply, the emphasis should be on selecting the best quality source water available, and on protecting its quality by the use of barrier systems and maintenance programs. Whatever the source (ground, surface or tank water), householders should assure themselves that the water is safe to drink.
• Information on the quality of surface or groundwater may be available from state and local governments conducting monitoring programs. If not, individuals should consider having the water tested for the indicators above and any key health characteristics identified as being of local concern. Where raw water quality does not meet the requirements of the Australian Drinking Water Guidelines (NHMRC & NRMMC 2004), a point-of-use device may be needed to treat the water.
• The NSW Private Water Supplies Guidelines provide information regarding monitoring and treatment of private supplies serving the public. These are available from NSW Health.
• In many cases it will not be possible for water at individual homesteads to comply with the Australian Drinking Water Guidelines (NHMRC & NRMMC 2004) without some form of treatment. Many homesteads traditionally take drinking water untreated from local streams. Even in pristine areas there are health risks associated with this practice. The Government recommends that drinking water, including water for cooking and bathing, is at least disinfected before use.
• Effective communication and education strategies may be needed to ensure that householders understand that when water is not of a potable quality, precautionary measures should be taken (e.g. avoiding ingestion, boiling drinking water). Such water may be of sufficient quality to be used for washing clothes, gardening, toilet-flushing and other non-potable uses.
• Many homesteads rely on tank water for drinking and cooking. The enHealth Council's, Guidance on the Use of Rainwater Tanks (enHealth 2004) is endorsed by the NSW Health Department and provides useful information on the safe operation of rainwater tanks. Information is also available in the NSW Health Rainwater Tanks Brochure (PDF 98KB, from www.health.nsw.gov.au/pubs/r/pdf/rainwater020067.pdf ).
• Turbidity and pH in ambient waters are likely to vary outside the criteria above. Treatment at the point of use is likely to be necessary to achieve criteria above. It is advisable to maintain pH within this range to protect plumbing and fittings from corrosion and scale.

Where the objectives apply

• These objectives apply to all current and future licensed offtake points for town water supply and to specific sections of rivers that contribute to drinking water storages or immediately upstream of town water supply offtake points. The objective also applies to subcatchments or groundwaters used for town water supplies.

Examples of key indicators and their numerical criteria

Key indicators for raw water for drinking water supply that is to undergo coarse screening only are listed below. These indicators are drawn from the National Health and Medical Research Council Australian Drinking Water Guidelines (NHMRC & NRMMC 2004).

Note that a wide range of treatment technologies are available (e.g. coagulation, flocculation, filtration, ion exchange, reverse osmosis, carbon adsorption columns) that enable the production of acceptable drinking water from almost any raw water. The ANZECC 2000 Guidelines do not specify criteria for the many types of water quality that could be involved.

Refer to the NSW Groundwater Protection Policy, (DLWC 1998b) for information on the management of groundwater quality.

All drinking water should comply with the Australian Drinking Water Guidelines (NHMRC & NRMMC 2004) at the point of use. Refer to the Summary in the Australian Drinking Water Guidelines.

* Values given are NHMRC criteria for raw waters before disinfection or clarification. Raw waters can have concentrations of faecal coliforms above the NHMRC criteria, even in pristine ecosystems. Slightly greater faecal coliform or total coliform contamination, may therefore be acceptable in raw waters that are to be disinfected before delivery to the consumer. (Faecal coliform criteria used in Victoria have suggested that for raw waters requiring only low-level treatment, natural background levels of 95% of samples should have <10 faecal coliforms/100 mL. For high-level treatment, 95% of samples should have <100 faecal coliforms/100 mL.) For a full discussion of drinking water system management and criteria, see the Australian Drinking Water Guidelines (NHMRC & NRMMC 2004).

Supporting information

• Refer to the summary of guideline values in the Australian Drinking Water Guidelines (section 10.8)
• While the Australian Drinking Water Guidelines 2004 do not recommend a specific raw water quality for treatment, the Framework for Management of Drinking Water Quality has been developed as a preventative risk management approach for the management of water quality from catchment to consumer.
• The Guidelines advocate "barrier systems" involving catchment management, appropriate treatment and monitoring to verify quality.
• The focus is on improving the quality of raw drinking water sources to protect public health and minimise treatment costs. In some cases, this will require controlling or removing pollutants from dedicated drinking water subcatchments, from upstream of river offtakes and from groundwater systems used for drinking water.
• Protection of zones upstream of raw water or reservoir inlets is essential, but may be feasible only over limited distances. The location and size of offtake zones will need to be defined based on further local community consultation. Upstream conditions will also need to be considered (e.g. existing land use, pollutant sources, climatic and river flow factors).
• The existence of an offtake zone acts as an indication of the need to protect drinking water at the point of supply and to identify upstream threats to those supplies.
• Some waterbodies used as a raw drinking water source may provide water of high quality that needs only disinfection before use. These waterbodies should be regarded as having a high environmental value and should be protected.
• Many town water supplies rely on pumping groundwater from aquifers or river alluvium.
• Water quality tests for faecal coliform bacteria are used as an indicator of the possible presence of human pathogens. Improved tests are being developed.
• The NSW Health Private Water Supplies Guidelines provide information regarding monitoring and treatment of private supplies serving the public.
• It is advisable to maintain pH within the range above at the point of supply, to protect plumbing and fittings from corrosion and scale.

Where the objective applies

• The objective applies to all waters where aquatic foods are taken for non-commercial and commercial harvesting.

Examples of key indicators and their numerical criteria

Indicators used to assess and monitor water quality so that it is suitable for the production of aquatic foods are summarised in the following table. Other indicators are listed in the ANZECC 2000 Guidelines and Food Standards Code (ANZFA 1996 and updates available at www.anzfa.gov.au).

Supporting information

• To protect the health of human consumers of aquatic foods (whether derived from aquaculture, commercial, recreational or indigenous fishing) the ANZECC 2000 Guidelines are intended to be used in conjunction with the Food Standards Code (ANZFA 1996 and updates available at www.anzfa.gov.au).
• The indicators are to assist managers to minimize the exposure of human consumers of aquatic food species (eg recreational fishermen) to bacteria-borne disease. In the case of commercial harvesting and cultured species the relevant requirements of NSW SafeFoods and the NSW Shellfish Projects Operations Manual need to be met. Also NSW Health recommends against the consumption of raw shellfish harvested on a non-commercial basis. All such shellfish should be thoroughly cooked to kill pathogens and minimize the risk of food poisoning. Cooking, however, cannot remove the risk of algae toxins or chemical contaminants.
• There is a need to identify all aquatic food sources to ensure that appropriate management is in place to protect the human consumer.
• The condition of the waterway must be suitable for both individual species and their habitats and must protect consumers from chemical contaminants that may accumulate in the tissues of aquatic foods or from human pathogens. Many waterways in NSW produce aquatic foods that are suitable for eating after cooking.
• NSW Health should be consulted about issues that have a direct public health impact and concerns about the safety of aquatic foods should be brought to the attention of local public health units.
• The potential for members of the public, including those in Aboriginal communities, who gather shellfish for subsistence or non-commercial purposes to be exposed to pathogens by eating raw shellfish needs to be considered.
• The potential presence of microbial pathogens (faecal bacteria, viruses, Cryptosporidium), algal and biotoxins and chemical contaminants needs to be considered when assessing the risks associated with shellfish consumption. In addition, an understanding of the catchment and actual and potential pollution sources that may impact on the water quality is essential.
• Water quality tests for faecal coliform bacteria are used as an indicator of the possible presence of human pathogens. Improved tests are being developed.

The high economic value of water taken from rivers and lakes for use by industry needs recognition in water quality planning and management. It has been identified as an important environmental value through community consultation.

As industry water supply needs are diverse, relevant water quality criteria are not summarised here and the ANZECC 2000 Guidelines do not provide guidance on the water quality needed for various industries. Sources of water used for industry invariably have other environmental values, which mostly need water of a higher quality than that needed by industry. Further, individual industries generally have the capacity to monitor and treat the available water resources to meet their own needs.

This page was published 1 May 2006