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New South Wales State of the Environment
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SoE 2003 > Water > 5.3 Surface water quality

Chapter 5: Water

5.3 Surface water quality

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5.3 Surface water quality

Many NSW waterways have poor water quality, with salinity in some projected to deteriorate. Reducing diffuse water pollution will be the key to improvement.

Under current land management practices, the salinity of some rivers in the Murray–Darling Basin will increase over the next 50 years to levels which will severely restrict water use. Assessments of total phosphorus and turbidity in NSW rivers show that water quality is generally poorer in inland catchments than in those on the coast. Most inland rivers have concentrations of phosphorus that could support excessive growth of algae and other aquatic plants. Cold water pollution is also now recognised as having an impact on regulated rivers.

There have been significant reductions in nutrients from some point sources of pollution. Much of the current nutrient and sediment water pollution in NSW originates from diffuse sources. This means better management of urban and rural runoff, particularly from cropping and poorly managed stock access to waterways, will be vital in achieving aquatic ecosystem health.

Algal blooms are a continuing problem despite efforts to better manage water quality and river flow.

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NSW Indicators


Status of Indicator

5.4 Point-source discharges to fresh waters and wastewater treatment

Initiatives to reduce phosphorus have been successful for some point sources.

5.5 Surface water salinity

Salinity levels are predicted to increase significantly in the future given current environmental conditions.

5.6 Exceedences of surface water quality objectives

Nutrient and turbidity levels remain high in inland areas. Coastal rivers are generally in better condition.

5.7 Freshwater blue-green algal blooms

Blue-green algal blooms continue across much of NSW. The number of catchments affected by high-alert blooms is similar to previous reporting cycles.

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Importance of the issue

Good quality water is vital for human health, aquatic ecosystems and economic activity. Water quality is affected mainly by pollution from point and diffuse sources, land management practices and alterations to flow rates caused by dams. Worldwide, point-source pollution has been regulated, while pollution from diffuse sources, such as agricultural and urban runoff, is being addressed mainly through the efforts of individuals (Australian State of the Environment Committee 2001) and local councils. A number of Healthy Rivers Commission inquiries have highlighted diffuse-source pollution as having a major impact on the health of NSW rivers.

Land degradation also has significant impacts on water quality (NLWRA 2002a). It can lead, for example, to the mobilisation of saline groundwater which damages local infrastructure, and cause increases in stream salinity, turbidity and sedimentation which impose significant costs on downstream water users (Hajkowizc & Young 2002).

Regulation of rivers is also an important factor that determines water quality. Storing or diverting water modifies river flows, reducing the dilution and dispersal of pollutants, degrading ecosystem health, and changing river morphology. These can all have significant impacts on water quality. River flows are discussed in Water 5.2.

A major indicator and consequence of an increase in nutrients in waterways are algal blooms. They reduce the environmental values of water by limiting its potential uses and imposing treatment costs. Freshwater algal blooms are a serious and widespread problem throughout Australia with an estimated national cost for managing them of between $180 and $240 million each year (LWRRDC 2000).

For more information on the sources and management of surface water pollutants and their impact on ecosystem health, see EPA 2000c.

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Sources of pollution

Point-source pollution

Point sources of pollutants include sewage treatment plants (STPs), industrial activities and discharges from urban stormwater drains. Point sources discharge a variety of pollutants to aquatic environments and have the potential to cause severe long-term impacts on water quality, and human and ecosystem health.

Point sources also alter river flow patterns when they contribute significant volumes during low flows. The low dilution potential at these times can concentrate such commonly discharged pollutants as nitrogen, phosphorus, faecal coliforms and other bacteria, suspended solids, oil and grease, salts, metals, bacteria and toxic organic compounds. Some water pollutants contain endocrine disruptors, chemicals which disrupt the hormones that control sexual development and growth. These can cause deformities in fish and other aquatic biota.

STPs are generally the major point-source discharges to fresh waters, particularly to inland rivers. Although they generally have some form of treatment, elevated concentrations of pollutants may occur immediately downstream of the point of discharge. As a result, rivers receiving large volumes of STP effluent may experience elevated levels of nutrients. These can cause excessive growth of organisms which depletes oxygen (eutrophication), as well as algal blooms. Untreated effluent can also reach waterways through sewer system overflows when the transport capacity of the pipe network is exceeded, typically during wet weather.

Some catchments are starting to show good results from programs to reduce the nutrient phosphorus at STPs. In terms of the volume of effluent treated, the nutrient loads from Hawkesbury–Nepean and Hunter STPs are low in comparison with other catchments, reflecting a higher level of treatment. Many of the State's STPs have had phosphorus reduction and other treatment system facilities upgraded, successfully reducing pollution loads. For example, Sydney Water reduced discharges of phosphorus from its STPs to the Hawkesbury–Nepean by 28% between 1999–2000 and 2001–02 (SWC 2002).

Diffuse-source pollution

Water pollution from diffuse sources is generated by runoff after rain, which collects pollutants from across a wide area. Diffuse sources in urban areas include road surfaces, industrial and commercial premises, parks, gardens and households. Stormwater runoff typically contains litter, nutrients, bacteria, pathogens, pesticides, heavy metals, sediment, oils and grease, and other pollutants.

In rural areas, diffuse sources include agricultural activities, such as cropping, irrigation, livestock grazing and intensive livestock industries, as well as forestry and unsealed roads. Rural runoff can contain elevated levels of sediments, nutrients, pesticides and other chemical applications. Activities such as cropping and land clearing can greatly increase diffuse-source pollution. Results from the National Land and Water Resources Audit show that the condition of many Australian river basins is strongly linked to vegetation cover, the intensity of land use, increased nutrient and sediment loads, and the loss of riparian vegetation (NLWRA 2002b). These all have an impact on the generation and nature of diffuse-source loads.

Diffuse sources contribute the vast majority of the annual nutrient load found in most surface waters. Figure 5.2 shows the estimated contributions of total phosphorus loads from one point source (STPs) and a range of diffuse sources for selected NSW catchments and subcatchments.

Figure 5.2: Estimated annual sources of total phosphorus for selected catchments

Figure 5.2

Download Data

Source: Diffuse-source data from Atech Group 2000 for the Border Rivers, Gwydir, Namoi, Central West, Lachlan, Murrumbidgee and Murray catchments; Baginska & Pritchard 2000 for the Manning and Richmond catchments; and NSW EPA, as at 2002 for the Hunter, South Creek, Port Jackson and Botany Bay catchments.

STP data from DLWC, as at 2002, and EPA, as at 2002

Note: For coastal catchments (the Manning, Richmond, Hunter, Port Jackson and Botany Bay catchments), only STP discharges to surface waters are included. Data are estimates only and actual pollutant loads may vary.

Contributions from diffuse sources ranged from 88–100% of the estimated annual total phosphorus loads generated. Similar results were found for diffuse sources of total nitrogen, which ranged from 74–99% of the estimated annual loads. It is important to note that STP discharges are the only point source included in Figure 5.2. Much of the STP loads in coastal catchments, such as the Manning, Richmond and Hunter, are discharged to marine and estuarine waters and all of these loads in the Port Jackson and Botany Bay catchments are discharged to marine waters through deep ocean outfalls. Although these discharges do not contribute to nutrient levels in surface water, they may have consequences for marine and estuarine health (see Water 5.6).

Diffuse sources are therefore clearly the most important origin of surface water nutrients in NSW. However, the relative importance of diffuse and point sources of pollutants varies from catchment to catchment and with the type of pollutant discharged. Point sources that discharge continuously into conditions dominated by low flows can have a greater impact than the higher annual loads of diffuse-source pollution. This is because diffuse sources of pollutants usually discharge during wet weather when high flows are able to dilute the pollutant concentrations. On the other hand, a diffuse-source pollution load may have a greater impact when pollutants are not quickly flushed from the system or assimilated.

Loads from diffuse sources are dependent on the intensity of various land uses. An assessment of the Murray–Darling Basin showed cropping generating just over 50% of the total phosphorus load, despite making up less than 10% of land use in the basin (Atech Group 2000). Figure 5.2 also shows the breakdown of diffuse phosphorus loads from different land uses within the selected catchments. In densely populated catchments, such as Port Jackson and Botany Bay, phosphorus from diffuse sources comes predominantly from urban runoff. In less urbanised catchments, such as the Border Rivers, Gwydir and Lachlan, agricultural runoff contributes most of the phosphorus.

Data on diffuse-source pollution is currently only available for nutrients. However, because the presence of nutrients is often a reflection of an erosion problem (NLWRA 2002b), the loads of other pollutants associated with erosion, such as sediment and pesticides, are also likely to be high in diffuse pollution.

Dealing with diffuse-source pollution is often cheaper than further reducing point-source pollution. For example, the cost of upgrading a modern STP to reduce phosphorus discharge can be as high as $10,000 per kilogram saved per year. In contrast, the cost of reducing phosphorus from some diffuse sources in the South Creek catchment has been estimated at $10–$200 per kilogram (McNamara & Cornish 2001), although this cost varies between catchments and land uses. These wide differences in costs may have major implications for deciding where and how to direct efforts to reduce pollution.

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Surface water quality

Salinity, phosphorus and turbidity levels are important determinants of the quality of surface waters and these are presented for NSW below. Limited information on temperature alterations and toxic pollutants is also included. It should be noted that pollutants such as trace metals, pesticides and other contaminants may compromise the achievement of water quality objectives regardless of salinity, phosphorus and turbidity levels. Consequently, the results reported should be viewed in terms of the variables tested and not overall water quality.

Detailed water quality monitoring data for NSW can also be obtained from the Community Access to Natural Resources Information (CANRI) website.


Naturally occurring catchment conditions can result in high salinity levels in Australian inland waters. Changes in land use can cause dryland and irrigation salinity and increase salt levels in water (see Land 4.3). Increasing surface water salinity is exacerbated by the highly regulated flow in many rivers of the Murray–Darling Basin (see Water 5.2). Discharges of saline wastewater from mines, power stations, paper mills and STPs are other sources of salts which reach waterways.

In addition to salinity levels, high salt loads can also degrade water quality and aquatic ecosystems. Loads may increase when standing waters, such as inundated wetlands and floodplains or river pools during low-flow periods, evaporate leaving high concentrations of salt behind. Rivers with high salt loads can also increase soil salinity when their water is used for irrigation (see Land 4.3). High salt loads have been found in the Murrumbidgee, Lachlan and Barwon–Darling rivers (Beale et al. 2000) and the Macquarie River (DLWC 2001a).

The water salinity information from the Key Sites Water Quality Monitoring Program for 1995–2001 (Preece 1998) has been analysed using the categories set in the NSW Interim Water Quality Objectives to protect aquatic ecosystems. Salinity was assessed using electrical conductivity (EC), which is a measure of the ability of water to conduct an electric current. EC is proportional to the concentration of total dissolved salts. Sites were assessed as 'good' if the median EC level between 1995 and 2001 was < 500 microsiemens per centimetre ((S/cm); 'fair' if in the range 500–1500 (S/cm, and 'poor' if it was > 1500 (S/cm.

All sites were judged to have good or fair salinity levels. Those with higher salinity levels were found in the Hunter, Murray–Riverina, Lachlan, Gwydir, Namoi, Castlereagh and Macquarie–Bogan catchments.

An audit by the Murray-Darling Basin Ministerial Council (MDBMC) has predicted future river salinities in the basin (MDBMC 1999). The audit estimated salinities for the years 2020, 2050 and 2100 for each river valley supplying water to the Murray or Darling rivers. The results in Table 5.4 show that many rivers face sharp increases in salinity to a point where many water uses are likely to be compromised.

Table 5.4: Estimated and predicted NSW river salinity, 1998–2100

Catchment or town

Average river salinity (EC)










Wagga Wagga




























































Source: MDBMC 1999

Note: Figures in italics exceed the World Health Organization-recommended 800 EC limit for drinking water. Figures in bold italics exceed the 1500 EC recommended for the protection of aquatic ecosystems.

The World Health Organization (WHO) has recommended a desirable upper salinity limit for drinking water of 800 EC. At a salt concentration of 1500 EC, WHO recommends against irrigation of leguminous pastures, forage crops, rice, maize and grain sorghum. In addition, adverse biological impacts are likely to occur in river, stream and wetland ecosystems at salt concentrations at this level (MDBMC 1999).

Salt loads are also predicted to dramatically increase over the next 50 years. For the major inland rivers in NSW, the most marked increases in total salt loads are predicted for the Lachlan, Bogan, Barwon–Darling and Namoi rivers (Beale et al. 2000).


Increased phosphorus is a major cause of freshwater algal blooms which can degrade aquatic ecosystems and cause severe restrictions to the use of water for human and stock consumption (see EPA 2000c). Nutrient pollution is often a reflection of sediment problems as much of the phosphorus enters waterways attached to sediment particles (NLWRA 2002b). This suggests that erosion caused by the loss of vegetation and a range of land uses is likely to be a major source of phosphorus (see Land 4.2). Other sources of phosphorus include point-source discharges from STPs and intensive livestock industries.

The information on phosphorus from the Key Sites Water Quality Monitoring Program for 1995–2001 (Preece 1998) has been analysed according to the categories set in the NSW Interim Water Quality Objectives to protect aquatic ecosystems. Map 5.2 presents the results.

Map 5.2: Exceedence assessment of median total phosphorus at selected NSW sites, 1995–2001

Map 5.2

Source: DLWC data, as at 2002; SCA data, as at 2002

Median total phosphorus was generally higher at inland sites than coastal sites where concentrations were mostly good or fair.

Most inland rivers had phosphorus levels able to support excessive growth of algae and other aquatic plants. Phosphorus concentrations in 80% of sites assessed across the State were classed as fair or poor. In 67% of sites, phosphorus and turbidity levels were found to be fair or poor, demonstrating a link between phosphorus and sediment inputs in NSW waters. Inland sites with poor phosphorus levels were found in the Lachlan, Border Rivers, Gwydir, Namoi, Macquarie–Bogan and Darling catchments. On the coast, the Richmond, Hunter and Hawkesbury–Nepean had a number of poor readings.

The National Land and Water Resources Audit has assessed the nutrient levels of NSW waterways (NLWRA 2001b). The audit estimated that annual phosphorus loads in river networks were on average nearly three times those before European settlement. Total nitrogen is believed to have doubled over the same period.

Total phosphorus levels appear to be related to turbidity. This relationship shows the role suspended sediments play in transporting nutrients and the importance of managing vegetation loss, riparian zones and soil erosion. Nearly half of NSW waterways have substantially elevated total phosphorus and suspended sediment loads, while they are moderately elevated in a further 40%.


Australia has naturally turbid waters because of its deeply weathered soils rich in clay-sized particles. These particles are readily transported to streams during storms where they can remain suspended in the water column for long periods. Natural turbidity is increased by sediment entering rivers after land clearing, particularly the removal of riparian vegetation, and agricultural practices, such as grazing and cropping (see Land 4.2). Flow regulation and water abstraction can also increase turbidity by causing riverbank erosion.

High turbidity affects ecosystem health by reducing the light available for plant growth and animal functions; smothering in-stream habitat; and harming the health of aquatic animals by damaging gills and other respiratory structures. For more information on the impacts of turbidity, see EPA 2000c.

The turbidity information from the Key Sites Water Quality Monitoring Program between 1995 and 2001 (Preece 1998) has been analysed using the categories set in the NSW Interim Water Quality Objectives to protect aquatic ecosystems. Sites were classified as 'good' if the median turbidity level was less than 5 nephelometric turbidity units (NTU), 'fair' if between 5 and 50 NTU, and 'poor' if over 50 NTU.

Turbidity was found to be fair or poor for 69% of the sites assessed. It was generally worse at inland sites than coastal sites. Inland streams are naturally more turbid than those on the coast, where the soils tend to be coarser and settle faster. The degree to which turbidity is greater inland as a result of natural soil properties has not been determined. Sites with poor turbidity levels were found in the Lachlan, Border Rivers, Gwydir, Namoi, Macquarie–Bogan and Darling catchments.

Pesticides and other chemicals

A wide and growing range of toxicants, including hydrocarbons, trace metals, pesticides and herbicides, is entering rivers, and their long-term effects are still unclear (NLWRA 2002b). The use of pesticides, herbicides and defoliants in broadacre farming, coupled with discharges of water from irrigated agriculture, can lead to contamination of waterways. Water quality monitoring in the major rivers of north-western NSW indicate that pesticide contamination occurs during the summer cropping season (DLWC 2000a; DLWC 2001c).

Many other potentially damaging chemicals are discharged to waterways from point sources (see EPA 2000c) and urban runoff.

Cold water pollution

'Cold water pollution' is the low-temperature water released into rivers from large dams during warmer months. Between spring and autumn the water stored behind large dams stratifies thermally into a warm surface layer overlying a cold bottom layer. Since many older dams are only equipped to draw water from the bottom of the dam, water that is much colder than the natural river temperature is released downstream, causing cold water or 'thermal' pollution (see EPA 2000c).

Cold water releases can delay the natural seasonal changes in river temperature and reduce the range of temperature variation, both seasonally and diurnally. As an example, Figure 5.3 shows the predicted natural and observed water temperatures for the Tumut River downstream of Blowering Dam. These variations to natural temperature regimes can have severe consequences for ecosystem health including:

  • a reduction in ecosystem productivity through interference with biological and chemical functions
  • a reduction in aquatic biodiversity and an abundance and growth of individual species through the elimination of temperature-sensitive biota, changes to animal metabolism, interference with breeding cycles, and a decrease in the development and survival of the eggs and larvae of fish and aquatic insects.

Figure 5.3: Effect of cold water releases from Blowering Dam on the Tumut River

Figure 5.3

Download Data

Source: NSW Fisheries data as at 2002

Cold water pollution is believed to be one of the main factors behind the severe decline in native warm water fish species in the Murray–Darling Basin.

At least 140 dams in NSW have a height of 15 metres or more where a cold bottom layer can develop on a seasonal basis. However, not all cause cold water pollution because of the configuration of their outlets and/or the pattern and destination of releases. From existing information, at least 10 sites are severely affected by cold water releases. These are mostly large irrigation supply dams which release high volumes of water directly to the downstream river channel, reducing summer temperatures by up to 12oC (DLWC 2001b). Although the impact is worst immediately below the dam, it may still be detected hundreds of kilometres downstream (Preece & Jones 2002). While the extent and severity of cold water pollution in NSW is unclear, estimates have suggested that more than 2500 kilometres of rivers in the Murray and Darling systems are subject to ecologically significant temperature modification (Whittington & Hillman 1998).

Ecosystem health can also be affected by temperature increases. The loss of riparian vegetation, a shallowing of river channels caused by sedimentation, and warm water discharges from industries can all increase water temperatures.

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Freshwater algal blooms

Most of the problematic algal blooms that occur in fresh water in NSW are caused by blue-green algae, which can produce potent toxins. Non-toxic blooms can also have significant impacts on aquatic ecosystem health, but the hazard associated with them is usually less than that of blue-green blooms. Problems associated with both toxic and non-toxic algal blooms include large diurnal fluxes in dissolved oxygen concentrations which kills fish and other aquatic species; changes in pH; reduced light penetration; and the smothering of habitat.

A number of environmental factors interact to enhance the risk of blue-green algal blooms developing in fresh waters. The major influences are a climate which provides suitable growth conditions, and elevated nutrient concentrations. Although algal blooms occur naturally in Australia, changes in land and water management since European settlement have enhanced the conditions that suit their rapid development. These changes include:

  • reduced flows and flow variability because of river regulation
  • removal of riparian vegetation, which increases the availability of light for algal photosynthesis and raises water temperatures
  • increased nutrient loads from such sources as erosion, STPs and the application of fertiliser.

Because of the relationship between nutrients and algal growth, blooms are sometimes regarded as a surrogate indicator of eutrophication or high nutrient load. These conditions, especially high nutrient concentrations, are present in many NSW rivers, lakes and water storages. For more information on algal blooms, nutrients and eutrophication, see EPA 2000c.

There is no routine monitoring for algae in NSW and the reporting of blooms often depends on population density and public vigilance. The ad hoc nature of such reporting means that it is not possible to determine statistically valid trends for the data available.

In NSW, the concentration of blue-green algal cells in a waterway is used to determine the risk for human drinking water and domestic and livestock uses. There are three alert levels based on the known toxic effects:

  • low – 500 to 2000 cells/millilitre
  • medium – 2000 to 15,000 cells/millilitre
  • high – above 15,000 cells/millilitre.

During a high alert, the water is considered unsuitable for drinking without prior treatment to remove the algae and all toxins present. It is also unsuitable for watering stock and other domestic uses, and primary contact recreation. Use of the water for some irrigation purposes, especially on leafy green salad vegetables, is also not recommended. Medium and low alerts mainly require increased surveillance and monitoring, although some treatment may become necessary during medium alerts where town water supply is affected.

High alerts were issued for 68 sites in 2001–02. While this is slightly higher than the number of high alerts issued in previous years, it does not necessarily mean that blue-green algal blooms have become worse in recent times. Many factors, and in particular climate, have major roles in determining if blooms will occur in a particular water body. High rainfall years with high flows are likely to lead to fewer blooms than in dry years with low river flows.

During 2001–02, the Hawkesbury–Nepean, Barwon–Darling and Hunter catchments were the most affected by high-alert blue-green algal blooms, in terms of the number of sites and blooms, and the period of alerts. High-alert blooms were also significant for the Sydney Coast and Georges, Namoi, Macquarie–Bogan, Lachlan, Murray–Riverina, and Lower Darling catchments. Many of the inland water storages had extended blooms.

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Response to the issue

The main responses to poor surface water quality are programs to reduce the amount of pollution entering waterways and improve river flow regimes. Responses to river extraction and flows are discussed in Water 5.2, while this section covers the major responses aimed specifically at surface water quality and reducing pollution including:

  • water quality objectives and targets
  • programs to reduce pollution from point sources
  • programs to reduce pollution from diffuse sources.

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Water quality objectives and targets

As part of its water reforms, the NSW Government recommended interim water quality objectives for 31 NSW catchments in October 1999. Regional integrated catchment management plans or 'Catchment Blueprints' have since been developed for 21 catchments (see Land 4.1). The Blueprints are 10-year plans that establish natural resource priorities for whole catchments. They contain end-of-valley salinity targets, as well as targets for nutrients and other water quality problems.

For coastal rivers that are the subject of Healthy Rivers Commission inquiries, Government Statements of Intent provide river health objectives, including the water quality needed for various uses and strategies to achieve it.

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Programs to reduce pollution from point sources

The EPA regulates major point sources of pollution in NSW. Activities scheduled under the Protection of the Environment Operations Act 1997 are licensed by the EPA, with comprehensive requirements for pollution control, monitoring, reporting and auditing. Pollution from small-scale activities is regulated by local government through the issuing of notices and planning controls. Both the EPA and local government take enforcement action when requirements are breached or following pollution incidents.

Two regulatory approaches to manage point sources are load-based licensing (LBL) and the Hunter River Salinity Trading Scheme. Based on the 'polluter-pays' principle, LBL provides industry with incentives to improve its environmental performance. The scheme requires licensees to pay annual fees based on the pollution loads they discharge and provides financial incentives for industries to reduce those loads. The scheme includes incentives for the sustainable reuse of effluent and for licensees who commit to future improvement through load reduction agreements. Over 20 agreements are in place, saving more than 1500 tonnes of pollution per year.

The Hunter River Salinity Trading Scheme regulates the discharge of saline water to the Hunter from 20 of Australia's largest coal mines and two power stations. The scheme ensures that salinity levels in the river do not exceed agreed targets.

Through the National Pollutant Inventory (NPI), industrial emitters across Australia are required to report annually on estimated emissions of 90 pollutants to water, air or land. The NPI aims to encourage industry to identify and change certain manufacturing processes to those that are cleaner or more efficient.

Sewage effluent management

The EPA is developing a policy to provide a clear framework for State and local government decision-making on options for sewage effluent management. The framework will ensure adequate consideration is given to the environmental, public health, social and economic implications of all available reuse and disposal options.

A program has been introduced to manage sewer overflows. Whole sewage treatment systems are now being licensed under the Protection of the Environment Operations Act 1997. This includes STPs and all associated components of the reticulation system, including pipes and overflow structures. The licences contain a range of operating and maintenance requirements as well as pollution reduction programs to improve the performance of both the treatment plant and the reticulation system.

Management of on-site sewage systems is also being addressed through the Septic Safe Local Government Program. A large number of on-site sewage systems have been registered and inspected across NSW and strategies developed to improve existing systems and plan new developments.

A range of other programs is improving the management of effluent from STPs including:

  • the Country Towns Water Supply and Sewerage Program, which helps country councils develop better water and sewerage services (DLWC 1999a)
  • the Priority Sewerage Program, which identifies priority areas for sewerage system improvements from an environmental and human health perspective within the operating boundaries of Sydney Water, Hunter Water, and Gosford and Wyong Councils
  • the Accelerated Sewerage Scheme, which is providing up to $20 million to reduce the impacts of sewage in Sydney's drinking water catchments
  • the NSW Government's Waterways Package including the $90-million upgrade of the Cronulla STP completed in April 2001 and the $197-million Illawarra Wastewater Strategy to transfer wastewater from Bellambi and Port Kembla STPs to Wollongong STP for treatment or reuse
  • a draft integrated effluent management strategy for the Hawkesbury–Nepean River system to help manage the projected impacts of population growth in western Sydney.

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Programs to reduce pollution from diffuse sources

Managing diffuse-source pollution is an integral part of overall catchment management. Catchment management frameworks are being developed through a range of processes: at the national level through the Natural Resource Management Ministerial Council and the Murray–Darling Basin Ministerial Council's Integrated Catchment Management Strategy; and at the State level primarily through Catchment Management Boards. At the local and regional level, efficient land-use practices and planning are crucial for mitigating the potential impacts of diffuse sources, both urban and agricultural.

There has been significant activity in recent years to reduce urban stormwater runoff. The NSW and Commonwealth Governments have allocated funds to help local government and other organisations manage stormwater. The NSW Government has established a five-year, $82-million program to tackle urban stormwater pollution.

Through this funding, stormwater pollution is being managed by:

  • NSW Stormwater Trust Grants – a four-stage program to fund the development by local government of innovative approaches to stormwater with the fourth and final round of grants totalling $15 million awarded in 2002
  • Stormwater Improvement Program – between 2000 and 2002, the Sydney Catchment Authority allocated approximately $1 million to assist local councils implement priority stormwater improvement works
  • stormwater management planning – a legal direction requiring local councils in NSW to prepare stormwater management plans for urban areas has resulted in over 130 plans submitted to the EPA
  • Urban Stormwater Education Program – funding of $7.4 million has been allocated over five years to implement a statewide education program (see EPA 2000e for more information).

In response to rural runoff, extension and education services as well as financial assistance is provided by NSW Agriculture, the Department of Infrastructure, Planning and Natural Resources and Sydney Catchment Authority. At both national and State levels, salinity management is being used as the driver for implementing reform in natural resource management (see Land 4.3). Many actions to address salinity are also likely to have broader water quality benefits.

Specific initiatives to improve rural runoff include:

  • community-led Landcare groups rehabilitating riparian zones and preventing land degradation (see Land 4.1)
  • management of pesticides in agriculture through the introduction of the Pesticides Act 1999, the Australian Cotton Industry Best Management Practices program, and Land and Water Management Plans in south-western NSW
  • a Sydney Catchment Authority–NSW Agriculture program to assist the dairy industry to better manage waste and minimise runoff.

The NSW Government has also been developing tools for managing diffuse-source water pollution in the future. In April 2002, the Government released a proposal on green offsets for sustainable development. The initiative includes a pilot scheme for trading between point and diffuse sources of nutrients in the South Creek catchment in western Sydney, and a pollution offset scheme to support sustainable development in Sydney's drinking water catchments. For more information, see EPA 2002a.

As part of an Urban Stormwater Initiative under its Living Cities Program, the Commonwealth Government allocated around $11 million over three years (1999–2002) for stormwater management to improve the health of urban waterways in major coastal cities and centres (Environment Australia 2000).

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Other responses

Other important responses to protecting surface water quality include:

  • management of algal blooms through the activities of Regional Algal Coordinating Committees and improving environmental flows in rivers throughout NSW (see Water 5.2)
  • NSW water quality monitoring programs undertaken by the Department of Infrastructure, Planning and Natural Resources, local councils and the Sydney Catchment Authority within Sydney's drinking water catchments
  • support for community water quality monitoring through the Waterwatch and Streamwatch programs
  • research into the impact of cold water from dams on aquatic ecosystem health funded by the Environmental Trust
  • monitoring of water quality in acid sulfate soil priority areas as part of the Acid Sulfate Soils Program (see Land 4.5).

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Effectiveness of responses

Most of the responses to water quality management have for many years focused on point sources. There have been significant reductions in pollutants from many point sources and nutrient pollution from STPs is also being reduced because of major investments by local councils and the State Government. As a result of these successes, diffuse water pollution has now become the principal challenge in attaining further gains in many areas.

The management of urban stormwater has improved in recent years. After the first three-year phase of the Urban Stormwater Program, an estimated 3600 tonnes of litter and coarse sediment was being prevented from entering NSW waterways annually. However, there has been less effort to reduce diffuse pollution in rural areas and several years of drought have reduced the visibility of the issue.

For cold water pollution, existing responses have been successful in raising awareness and a better understanding of the scope of the problem. However, it is likely to be several years before significant advances are apparent because of the long lead times in designing, constructing and commissioning new infrastructure. Significant resources will be required but it is not clear if these will be available.

The incidence of algal blooms remains high despite efforts to better manage water quality and river flow. The elevated levels of nutrients found in many NSW waters, particularly in inland areas, are a major contributor to the problem. This has been demonstrated in western Sydney, where a reduction in nutrient loads from STPs has decreased the frequency and intensity of algal blooms (SWC 2001). The benefits of improved environmental flows is difficult to assess, as the long-term data is insufficient. However, early evidence from the Integrated Monitoring of Environmental Flows program shows that flushing flows can disrupt blue-green algal growth (DLWC 2001d).

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Future directions

Increased effort is required to manage diffuse water pollution, particularly in rural areas. Government needs to work in partnership with land managers to further explore ways to reduce runoff of pollutants from agriculture. Land-use planning is also crucial in mitigating the potential impact of diffuse sources, both urban and agricultural. In addition, operators and regulators should continue their efforts to address remaining point sources that make significant contributions to pollution loads.

Landholders can improve whole-farm practices to reduce runoff of nutrients and other pollutants. They can also continue to work with agencies to protect and restore riverine corridors to help prevent pollution from entering rivers. Information on sustainable land management practices and financial assistance is available from the Department of Infrastructure, Planning and Natural Resources.

Individuals can make simple changes to their everyday behaviour to help reduce water pollution and protect waterways, for example:

  • not using sinks to dispose of harmful materials, such as oils and grease, medicines and other chemicals
  • composting food scraps or putting them in the bin rather than washing them down the sink
  • using washing detergents with low or no phosphorus and using them sparingly
  • washing cars on the lawn or at a carwash where the water is recycled
  • cleaning up animal waste and disposing of it in the rubbish bin.

The Department of Infrastructure, Planning and Natural Resources, EPA and Sydney Catchment Authority have more information and advice on how to reduce the pollution of waterways.

Monitoring will be needed to assess whether the water quality targets in Catchment Blueprints are being met. Results from this monitoring will be vital in determining the success of measures to improve water quality and will enable the identification of priorities and any further problems.

More information is needed on:

  • the potential impacts of pollutants other than nutrients from point sources
  • the impacts of diffuse-source water pollution, including how variations in its magnitude and characteristics affect receiving waters
  • the characteristics of diffuse runoff, including the chemical form of the pollutants
  • the effectiveness and costs of various management actions to reduce pollution from diffuse sources
  • the occurrence, magnitude, duration and extent of cold water pollution and toxic pollutants.

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Linked issues

2.1 Population and settlement patterns

2.2 Urban water

4.1 Land-use changes

4.2 Soil erosion

4.3 Induced soil salinity

5.1 Freshwater riverine ecosystem health

5.2 Surface water extraction

5.5 Groundwater quality

5.6 Marine and estuarine water quality

5.7 Sediment contamination

6.6 Aquatic ecosystems

6.7 Aquatic species diversity

6.9 Aquatic harvesting

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