Water resources - Quality
National overview of surface water quality issues
Deteriorating water quality increases the cost of treating water for domestic and commercial use. It affects industries as diverse as tourism, fishing and agriculture. Ecologically, poor water quality affects the variety and abundance of plant, fish and other animal life in our rivers, wetlands and estuaries.
Management is best based on knowledge of existing water quality. Getting and processing data to define surface water quality issues in Australia has been one of the tasks of the National Land and Water Resources Audit in partnership with the State of the Environment Reporting section of Environment Australia and State and Territory agencies.
Using information supplied by State and Territory Agencies, the Audit has for the first time compiled an Australia wide overview of catchments with major salinity, nutrient, turbidity and acidity / alkalinity water quality problems. Where data was available, assessments of blue-green algal blooms and faecal coliform contamination have also been completed.
Other important surface water quality issues in Australia include toxic chemical and heavy metal pollution, organic carbon loading, oxygen depletion, thermal pollution and biological pathogens. Information on these issues is limited and localised and is not part of this Audit.
The Summary of Surface Water Quality Issues map provides an Australia-wide overview of four water quality variables: turbidity, nutrients (total nitrogen and total phosphorus), salinity and acidity/alkalinity (pH).
These four issues are significant across much of Australia including most of the intensive land use areas. Assessing water quality issues was nevertheless constrained by monitoring coverage in each river basin. For much of Australia there is no water quality monitoring. Water quality monitoring is one input into an overall assessment of Australia's natural resources. Other supporting information is also being drawn from the Audit's assessments of river basin water use, sediment and nutrient exports, estuary and waterway condition.
This assessment is a snapshot based on records of water quality guidelines being exceeded. Of the four major water quality issues, nutrient exceedances affected the greatest number of river basins followed by turbidity, salinity and acidity / alkalinity (pH). Data for trend analyses was limited but where available generally indicated the absence of obvious trends for most basins. In basins where trends were detected, increases in turbidity and total phosphorus, and decreases in pH (increasing acidity) predominated. The trends for total nitrogen and salinity were split, with an approximate equivalent number of basins showing decreases and increases. Some of this variation may be associated with climatic events (high and low rainfall) during the record period. However, dryland and irrigation associated soil salinity, both key contributors to surface water salinity, are expanding, therefore the number of river basins affected by surface water salinity is expected to increase.
Turbidity
Findings
Turbidity is a major surface water quality issue in Australia. The affected areas included most inland and lower rainfall basins of the North East drainage division, most of the Murray-Darling drainage division and the more intensively developed basins of the southern South-East Coast drainage division. Turbidity was not an issue in the relatively well vegetated, less developed and higher rainfall coastal basins within the North-East Coast, South-East Coast and South West Coast drainage Divisions,
While constrained by data availability, most observed turbidity trends were of increasing turbidity:
- in the Murray-Darling Drainage Division at least five affected basins had increasing turbidity while three affected basins had decreasing basin turbidity.
- in the South-East Coast Drainage Division at least two affected basins had increasing turbidity and one affected basin had decreasing turbidity.
- four basins without recognised turbidity problems in the southern NSW section of the South-East Coast Drainage Division recorded increasing turbidity
This assessment was constrained by data availability and the monitoring coverage within individual river basins. The ability to assess whether turbidity was associated with extensive land use in the Indian Ocean, Timor Sea, Gulf of Carpentaria and Lake Eyre Drainage Divisions was also prevented by lack of data.
Context
Australia is a dry continent with variable rainfall and stream flow with large areas of highly erodable soil types. These factors often combine to create naturally high levels of turbidity in Australian surface waters. They also make the Australian landscape vulnerable to soil erosion. For this assessment, the Audit used State and Territory based water quality guidelines that reflect to varying degrees, regional distinctions in 'natural' water quality. However, more information on the natural characteristics of river basins may support the establishment of more lenient turbidity guidelines. This would allow for better water quality assessments where soil and flow conditions generate naturally high levels of turbidity.
Impacts
Turbidity affects water clarity and consequently light penetration. This in turn affects ecological processes that depend on sunlight including primary production by aquatic plants and plankton growth. Light penetration also affects the temperature regime of surface waters. Suspended sediments clog gills and filter feeders and smother sedentary aquatic plants, animals and their eggs. In extreme cases, catchment erosion, high turbidity and consequent sedimentation within watercourses can significantly alter the physical habitat of instream environments. This produces shallowing of pools and buries coarse bottom sediments leading to a loss of habitat and spawning sites for gravel bed dependent fish. In an aquatic ecosystem these impacts can generate flow on effects through food chain linkages.
Turbidity generated within a catchment can be exported to estuarine and coastal marine environments. Turbid water exported from catchments during floods has been implicated in the demise of coastal sea grass beds and fringing coral reefs. In addition to impacts associated with reduced water clarity and sediment smothering, turbid water can carry significant amounts of nutrients into estuaries and coastal waters, because nutrients such as phosphorus bind to the suspended soil particles.
Increased turbidity can directly impact on social and economic values. It reduces recreational opportunities and can affect industries such as fishing, aquaculture and tourism. Turbidity can also increase the cost of treating water for industrial and domestic use, affect pumps and irrigation infrastructure, increase flooding (due to reduced channel capacity) and lead to sedimentation of reservoirs and other water stores.
Managing surface water turbidity
Common characteristics of river basins affected by turbidity often include climate and intensity of land use. They usually contain areas largely cleared of native vegetation, support high levels of agriculture and/or pastoral development and have seasonally dry climates with generally variable rainfall. In contrast, river basins in which turbidity was assessed as not being significant have greater natural vegetation cover, and higher, and more even rainfall.
In the basins in which turbidity is a major water quality issue, management efforts need to counter practices that contribute to soil erosion that ultimately finds its way to surface waters through catchment run off. Management also needs to be directed at identifying means of intercepting soil mobilised by erosion before it reaches surface waters.
Catchment management seeking to reduce surface water turbidity needs to consider a range of initiatives under two strategic approaches that are not mutually exclusive, including:
Reducing soil erosion
- Planning to protect unsuitable soils, steep slopes, and riparian buffers from inappropriate clearing and use.
- Rehabilitation of areas affected by severe sheet, gully and bank erosion by land use retirement, contouring and revegetation.
- Development and adoption of best management practices / codes of conduct by agricultural industries eg, timing (in relation to rainfall) and number of cultivations; use of contouring and stubble / ground cover blanketing.
- Development and adoption of best management practices by pastoral industries eg. conservative grazing intensities and frontage and erodable slope exclusion fencing.
- Improved design and implementation of erosion control during road construction
Intercepting water born suspended solids
- Protective management and rehabilitation of riparian vegetation areas
- Maintenance and construction of catchment scale sediment retention /trap features including wetlands and detention basins within urban and agricultural landscapes.
There are two key challenges to combating turbidity problems. (1) the problem usually originates from a range of diffuse sources rather than a specific point, and (2) the impacts upon common property resources are often due to cumulative actions upon private property.
In some instances the potential for downstream impacts on nationally valuable resources such as Ramsar wetlands and protected marine areas such as the Great Barrier Reef Marine Park, provide some statutory capacity and impetus for Commonwealth government policy initiatives to support State and territory activities.
Salinity
Findings
Salinity is a major surface water quality issue in much of temperate southern Australia. It affects basins in most of the South-West Coast, the southern South-East Coast and southern Murray-Darling drainage divisions. Four basins in western New South Wales within the Murray Darling Drainage Division, one east coast basin in the South Coast Drainage Division (Hawkesbury) and three basins in the South Australian Gulf also recorded major and significant salinity exceedances. Assessments also revealed that two tropical and several sub-tropical Queensland basins in the North-East Coast Drainage Division had basin scale salinity exceedances. In at least three of these basins, however, tidal influences in the lower river monitoring stations, may have skewed the results.
In contrast most coastal river basins in the North East Coast and South East Coast Drainage Division, many of the upper and lower basins in the Murray Darling Drainage Division and four near coastal basins in the South-West Coast Drainage Division indicated no major of significant exceedances of salinity guidelines.
Surface water quality in terms of salinity refers to salt concentration and should not be confused with salt loads. Stream flow can dilute salt concentration, so that basins may export high salt loads but not exceed surface water salinity guidelines. This is the case of some basins such as the Murrumbidgee, which recorded good salinity levels (salt concentration), but is know to export significant salt loads downstream (Murray Darling Basin Ministerial Council 1999).
Trend analyses were constrained by available data, but where available, the data indicated both increasing and decreasing trends:
- In the North-East Coast Drainage Division, two basins where salinity is not yet recognised as a basin scale exceedance issue, the Manning and the Burdekin, had increasing salinity
- Two basins in the South-East Drainage Division also showed increasing salinity while another two showed decreasing salinity
- Within the Murray-Darling Drainage Division at least 4 affected basins had decreasing trends while three affected basins had increasing trends. A basin not yet recording salinity exceedances (Lower Murray) and another with limited monitoring coverage (Mallee) also showed decreasing trends
The Murray Darling Basin's Salinity Audit (Murray Darling Basin Ministerial Council 1999) predicts increased salinity for almost all river basins within the Murray Darling Drainage Division through to 2020, 2050 and 2100. The trends identified in this assessment are based on observed river salinity values over a proceeding 8-10 year period. While such trend assessments are important for tracking changes in river salinity they have a limited capacity to predict salinity values. This is because of the non linear nature of salinity trends which are driven by climate, water diversion patterns and complex interactions with groundwater levels and salt stores. In comparison the predictive method used in the MDBMC (1999) study incorporates modeling of groundwater rise and salt load mobilsation processes and highlights the complexity of developing a predictive capacity for surface water quality.
The availability of data and the intensity of monitoring coverage limited the assessment. Salinity guideline exceedances could also be expected in some basins with insufficient monitoring coverage in the South-Australian Gulf, the southern South-East Coast and the Murray Darling Drainage Divisions, as all these areas have significant soil salinisation.
Context
Australia's dry climate and ancient weathered landscape result in naturally high stores of salt being present within a range of soil types. These factors often combine to create relatively high 'natural' salinity levels in Australian surface waters. State and Territory based water quality guidelines reflecting regional distinctions in 'natural' water quality were used for the Audit.
Impacts
For most freshwater organisms high levels of salinity cause major physiological stress resulting in changes in aquatic biotic communities and a significant loss of diversity. Salinity inhibits or prevents the growth of many aquatic plants affecting primary production and causing the loss of important microhabitats. Salinity impacts upon riparian vegetation further reducing habitat and increasing the potential for bank erosion.
High surface water salinity also has economic and social impacts. Salinity increases the cost of treating water for drinking, reduces the suitability / availability of water for irrigation and other industrial applications, and contributes to the loss of productive land (through the use of unsuitable irrigation supplies) and impacts on public infrastructure. Other social impacts include reduced recreational opportunities and aesthetic impacts.
Managing surface water salinity
Management actions required to address surface water salinity are often linked to those needed to address soil salinisation which is one of the key drivers behind increasing surface water salinity.
River basins with major salinity water quality issues are commonly characterised by similar land use patterns and climate. Most have low levels of natural vegetation cover, and a seasonally dry climate with generally low rainfall. Irrigated agriculture is also a significant land use in many of the affected basins.
In such situations there is often a high risk of soil salinisation due to accumulated salt stores within the (unflushed) soil profile and the prospect of rising water tables associated with changes in the landscape water balance. These changes in the landscape water balance are usually associated with the replacement of deep-rooted native vegetation with shallow rooted crops and pastures, and/or the contribution of deep drainage 'leakages' from irrigated agriculture. Rising water tables mobilise salts stored in the soil profile which find their way to surface waters though saline groundwater discharges or via surface catchment run off.
Management of both soil and surface water salinity is therefore associated with restoring the water balance within the landscape. However some of the management options promoted to address soil salinisation for example engineering solutions such as deep drainage or groundwater de-watering, can increase salinity levels in receiving surface waters.
The nature of groundwater systems ie, whether they are local or regional in magnitude, will affect the likely success and response times of potential management options. Regional groundwater systems may accommodate more than 100 years of rising groundwater before the water table approaches the surface. Consequently, response times in terms of reducing groundwater levels are of an equivalent duration. Local groundwater systems fill and respond more rapidly to intervention. The Audit's mapping of regional, intermediate and local groundwater systems provides an appropriate operational framework for planning restorative and preventative management actions to address bother surface water and soil salinity. These include but are not limited to:
- Increasing the efficiency of irrigation systems to reduce deep drainage losses from crop lands and supply infrastructure (ie channels)
- Catchment revegetation particularly of key groundwater recharge areas
- Changing agricultural land use from shallow rooted crops and pastures to deep-rooted perennials
- Supporting the implementation of property management planning which addresses vegetation retention, revegetation and water management planning
- Delineating salinity risk constraint areas for use in development applications
- Implementing conjunctive (surface / groundwater) water use strategies
- Implementing water diversion and flow allocation strategies that maintain instream dilution flows
Nutrients
Findings
Nutrients (total phosphorus and total nitrogen) are a major surface water quality issue in Australia affecting most of the more intensively developed basins in the North-East Coast, Murray-Darling, South-East Coast and South-West Coast drainage divisions. Basins assessed to have nutrient levels within guidelines include the relatively well vegetated and less developed basins in areas such as north Queensland, north eastern Victoria and south western Australia.
Nutrient trend analyses were more constrained by the availability of data than analysis of exceedances. The available trend data indicated that:
- Six of the affected basins within the Murray-Darling Drainage Division had decreasing nutrient concentration, with two basins increasing nutrient concentration.
- Six affected basins within the southern Victorian section of the South East Coast drainage Division showed increasing nutrient concentration, and three affected basins decreasing nutrient concentrations
- One basin in the North-East Coast Drainage Division (Tweed) also showed a clear increasing nutrient concentration.
Data availability and monitoring coverage within individual river basins limited this assessment. Monitoring coverage for total nitrogen was more limited than for total phosphorus and was not available for some states - see map below. Major or significant nutrient issues may not be detected where monitoring coverage is insufficient or non-existent. This could particularly apply to river basins with poor monitoring coverage in the North-East Coast, South-East Coast, South Australian Gulf and South-West Coast Drainage Divisions, which are characterised by more intensive land use, recognised to pose risks to surface water quality in terms of nutrient loading.
Context
Australia has a wide variety of soil and vegetation types and climatic regimes, all of which affect the natural nutrient status of surface waters. State and Territory based water quality guidelines reflecting regional distinctions in 'natural' water quality were used for the Audit. However, further research concerning the natural characteristics of river basins and the capacity of their aquatic ecosystems to assimilate nutrients may support the establishment of more site-specific nutrient guidelines.
Impacts
Surface waters nutrients are essential for aquatic ecosystem food chains. However, excessive inputs lead to nutrient pollution known as eutrophication. The impacts of eutrophication include excessive growth of nuisance aquatic plants including algae that can smother bottom habitats and choke waterways and estuaries. Flow on ecological effects include the loss of important feeding and breeding habitats such as sea grass, and impacts on benthic animals such as corals. Decomposing organic matter produced by excessive aquatic weed and algal growth can lead to oxygen depletion and in some cases, fish kills. High nutrient levels in surface waters also promote blue-green algae blooms, which can contain compounds toxic to humans and stock. Eutrophic waters also provide an ideal environment for pathogens that can increase the incidence of infections and disease in exposed wildlife and people.
Nutrient loads generated within a catchment are usually exported to estuarine and coastal marine environments. Nutrients derived from upper catchment land uses exported from catchments during floods have been implicated in the demise of coastal sea grass beds and fringing coral reefs.
Ecological impacts can lead to a loss of biodiversity within affected aquatic ecosystems. Social and economic impacts include increased costs of water treatment, public health risks, loss of amenity values (fishing, swimming, boating, aesthetics), reduced fisheries productivity and impacts on tourism.
The national overview of surface water exceedances of total phosphorus guidelines indicates that phosphorus was the main driver of recorded nutrient exceedances.
The similarity between basins with phosphorus exceedances and those with turbidity exceedances highlights the recognised role of suspended sediment as a transporter of bound phosphorus.
Basins that did not have phosphorus exceedances ie, smaller coastal basins with better vegetation cover and more even rainfall, also tended to not have turbidity exceedances.
The national overview of surface water exceedances of total nitrogen guidelines shows the more limited data available for total nitrogen. Some assessments revealed exceedance patterns for nitrogen were distinct from those observed for total phosphorus. Some larger inland basins ie, the Mallee, Murrumbidgee, Burnett, Fitzroy, that recorded major exceedances for total phosphorus, recorded only significant exceedances for total nitrogen. In contrast, some smaller more coastal basins ie, the Preston, Thomson, and Herbert that did not record exceedances for total phosphorus, recorded significant exceedances for total nitrogen.
These differences in exceedance patterns between the two main classes of nutrient indicate different nutrient sources. This highlights the need for specific management initiatives to deal with nutrient loads generated from different catchment activities and land uses.
Managing surface water nutrients
Most of the assessed river basins within the more intensive land use areas of Australia have significant or major exceedances of nutrient water quality guidelines.
Two nutrients are the main contributors to the eutrophication of Australian surface waters: phosphorus and nitrogen (see separate maps below). Both nutrients occur in a number of chemical and physical forms and are derived from a range of diffuse and point sources. Organic carbon is also implicated in the nutrient loading of surface waters but due to limited data availability was not part of the Audit.
Phosphorus and nitrogen loading within surface waters comes from natural sources such as soil, organic matter and rainfall, and land uses sources including domestic animal waste, fertilisers, storm water run off, sewage and industrial discharges. Knowing the source and relative contribution of nutrient types from different land uses within a catchment is fundamental to any catchment strategy seeking to manage nutrient loading. At a local and sub-catchment scale, nutrient loading from point sources such as sewage plants and diffuse sources such as fertiliser used in intensive agriculture and horticulture, both contribute significantly to surface water nutrient loads. However, nutrient budgets for entire river basins often point to a more significant contribution from other diffuse sources such as soil erosion and domestic animal wastes.
Catchment management efforts seeking to reduce the nutrient loading of surface waters need to identify methods of reducing the number and contribution of catchment nutrient sources. This includes recognising the fundamental link between nutrients and turbidity. Because nutrients bind to suspended sediments in the water, soil erosion contributes to both turbidity and nutrient pollution. Management also needs to consider ways of intercepting and assimilating within catchments the nutrient loads that result from soil erosion and land use activities to ensure that catchment nutrient exports remain within ecologically sustainable limits.
Catchment management planning for nutrients should consider a range of initiatives under these two strategic approaches which are not mutually exclusive. These include but are not limited to:
Reducing nutrient sources
- Reduce soil erosion (see turbidity management).
- Development and adoption of fertiliser best management practices / codes of conduct by agricultural, horticultural and pastoral industries.
- Further implementation of tertiary and /or land based sewerage treatment.
Intercepting and assimilating nutrients
- Maintain and rehabilitate riparian vegetation and wetland areas.
- Maintain, design and construct catchment scale sediment and nutrient retention /trap features including artificial wetlands and detention basins within urban and agricultural landscapes.
pH
Findings
The monitoring coverage for pH is limited primarily to Queensland and Victoria. The main affected areas were tropical Queensland coastal basins within the North-East Coast Drainage Division and the Campaspe basin within the southern Murray-Darling Drainage Division. Several other basins within the southern Murray-Darling Drainage Division and one each within the, South-East Coast, South-West Coast and North-East Coast Drainage Divisions also significantly exceeded pH guidelines. Problems were well documented but not necessarily well monitored in other basins. For example, acid-drainage water quality problems have been detailed for a number of north coast NSW catchments (NSW EPA 1997).
Both low pH (acidic) and high pH (alkaline) exceedances were recorded, sometimes from the same basin. The weighting of lower basin, floodplain/coastal sampling sites may bias the exceedance records in some coastal catchments.
Data to support trend analyses were limited to Victoria, Queensland and South Australia. In the Victorian section of the Murray Darling Drainage Division, trend analyses identified increasing pH in one basin and decreasing pH (increasing acidity) in six basins, only one of which was recognised to currently exceed pH guidelines. In the South-East Coast Drainage Division, decreasing pH was recorded in four basins and increasing in three basins, all of which did not have existing pH guideline exceedances. Two Queensland basins in the North-East Coast Drainage Division also exhibited pH trends: the Brisbane (increasing pH) and the Fitzroy (decreasing pH).
Managing surface water pH
The natural pH of Australian surface waters is highly variable and is driven by a range of factors including underlying geology, organic loading, flow characteristics and climate. State and Territory based water quality guidelines for pH reflect some of this variability, with some states such as Victoria setting specific guideline for individual basins under State Environment Protection Policies. Queensland uses national ANZECC guidelines but has recognised that naturally acidic floodplain wetlands may sometimes record exceedances. Australia-wide, the development of more site, and regionally specific pH guidelines could be warranted in order to accommodate natural surface water conditions outside the existing guidelines.
The predominance of decreasing pH (increasing acidity) trends in Victoria, highlights the need for further investigation. The relationship between surface water acidity and a range of drivers including land degradation processes such as soil acidification is recognised (Harris 2000)
Many of the pH exceedances were located in coastal basins perhaps reflecting natural floodplain conditions or the disturbance (oxidisation) of insitu acid-sulphate soils. Increasing pH in non-coastal areas could be associated with land degradation (ie. soil acidification) and may indicate an emerging surface water quality issue. Other potential causes of surface water pH exceedances include acid rain (a major issue in the Northern Hemisphere), acid mine drainage, industrial discharges, and organic loading of slow flowing or still waters.
Catchment management plans to address pH exceedances first needs to identify the source of the problem. Appropriate management initiatives could include:
- Better management of industrial (including mining) point source discharges
- Preventing and managing the exposure of acid sulphate soils to reduce the potential for acid drainage to surface waters
- Reducing organic loading to surface waters
- Improved soil husbandry (including fertiliser use) to prevent structural decline and acidification.
Surface water quality monitoring in Australia
In Australia, monitoring of surface water quality is undertaken to provide information for a range of purposes including to:
- protect public health
- protect aquatic ecosystems
- assess waterway condition
- ensure compliance with discharge licences
- State of the Environment /Audit reporting
- improve scientific understanding of catchment processes, and
- identify water quality relationships and responses to land management practices
Australia spends $142 - 168 M per year monitoring water quality (Atech 2000). This is undertaken by:
- Commonwealth / Regional agencies
- Local and State government agencies involved in environmental monitoring and pollution regulation
- Government agencies or government owned corporations providing community services (ie. water, sewage)
- Private companies or organisations whose activities may cause water pollution (eg. mines, industrial plant operators)
- Research groups including universities, CSIRO
- Community Groups such as WaterWatch
To assess surface water quality guideline exceedances and trends, data was obtained from all the major State and Territory agency water quality monitoring programs. However, data was not obtained from other sources because:
- access was limited by ownership issues;
- access was too costly due to poor database management;
- data was only relevant to a specific area of research interest or licence;
- data was collected using non-standard procedures;
- data was collected for only a short time period; or
- data was of poor quality.
Where available, data was obtained for six water quality variables including, salinity, turbidity, total nitrogen, total phosphorus, pH and faecal coliforms. Data for other important water quality variables was limited and localised and was not part of the Audit.
To enable defensible exceedance and trend analyses to be conducted, stringent data quality and length of record requirements had to be met. This reduced the amount of available water quality data.
Where is surface water quality being monitored?
Coverage
Water quality data that met the requirements for exceedance or trend analyses for at least one water quality variable were available for 113 of the 246 river basins in Australia. Data was primarily limited to the more developed areas, often in those basins where water quality has already been an issue. This includes most of the North-East Coast, South-East Coast, Murray Darling, South-West Coast and the South-Australian Gulf Drainage divisions. Victoria had the best coverage, followed by New South Wales, Queensland, Western Australia and South Australia.
Areas that lacked water quality data suitable for analysis included: all of the Northern Territory and Tasmania, most of the northern tropics, central and southern arid regions including the Indian Ocean, Timor Sea, Gulf of Carpentaria and Lake Eyre Drainage Divisions.
Table of River Basin Water Quality Data Analysis Coverage for Different Water Quality Variables
| Water Quality Variable | River basins with sufficient data for site exceedance assessment* | River basins with sufficient data for site trend assessment** |
|---|---|---|
| Total Phosphorus | 101 (41%) | 64 (26%) |
| Total Nitrogen | 75 (30%) | 41 (17%) |
| Electrical Conductivity | 112 (46%) | 99 (40%) |
| Turbidity | 98 (40%) | 74 (30%) |
| pH | 73 (30%) | 61 (25%) |
| Faecal Coliforms | <1% | <1% |
% Figures indicate proportion of Australia's 246 basins
* At least three years of monthly data collected since 1995
** 7-10 years of monthly data collected since 1990. Flow measurements must have also been undertaken.
Exceedance Analyses
The number of exceedance analyses assessed per river basin largely paralleled monitoring station density. Agency monitoring programs capable of assessing a wider range of water quality variables usually covered areas of greater land use intensity. Data coverage for each variable relates to the ease and cost of measurement. The variables with the greatest coverage were salinity, followed by turbidity, total phosphorus, total nitrogen and pH.
Faecal coliform data were only available for small number of sites within Qld and the ACT. However, the Audit did not obtain faecal coliform data, from local government sources or corporate service providers which have the prime responsibility for monitoring surface water from a human health perspective.
Trend Analyses
Due to the more stringent data demands for trend analyses, available data was better able to support guideline exceedance analyses than trend analyses. For water quality trend assessments, salinity had the greatest coverage followed by turbidity, total phosphorus, pH and total nitrogen.
However, it is encouraging that generally sufficient salinity data existed to assess trends for most of the more intensively developed catchments. There was also relatively good coverage of turbidity data to support trend analyses in the intensive land use areas.
One apparent limitation in terms of trend data coverage for key water quality issues concerned nutrients. Only Victoria had statewide monitoring of both nitrogen and phosphorus with sufficient sampling frequency to provide data for good trend analyses. Australia-wide total phosphorus had much greater data coverage than total nitrogen. This probably reflects the view that phosphorus concentrations are the major limiting factor in algal blooms and eutrophication, and hence more important to monitor than total nitrogen concentration (a concept being challenged by new research findings).
Although pH is readily and cheaply measured in the field it was not widely reported, possibly because acidification of surface waters is yet to be identified as a significant issue for most inland waters. In fact, the low priority given to acidification might explain why much of the pH data already collected, is yet to be analysed.
Number of Water Quality attributes per basin for which exceedance analyses could be assessed.
Number of Water Quality attributes per basin for which trend analyses could be determined.
The following table lists the coverage of water quality monitoring in Australia by State:
| State | Number of stations used in water quality reporting | % of drainage basins reporting water quality |
|---|---|---|
| Australia | 707 | 49.19 |
| Australian Capital Territory | 5 | 1 |
| New South Wales | 100 | 31 |
| Northern Territory | ||
| Queensland | 245 | 36 |
| South Australia | 22 | 12 |
| Tasmania | ||
| Victoria | 184 | 28 |
| Western Australia | 156 | 19 |
Click on the State name in the table to view a report for that State.
Future challenges for monitoring of Australia's surface water quality
Even with an annual investment of about $150m, water quality monitoring in Australia, has a limited ability to assess and report on the status of Australia's surface waters.
Progress
In terms of achievements, Australia has:
- Ongoing implementation of a National Water Quality Management Strategy (ANZECC / ARMCANZ 1994)
- National Water Quality Guidelines (ANZECC 1992 & in prep).
- National Guidelines for Water Quality Monitoring and Reporting (ANZECC in prep)
- Regionally defined water quality guidelines and management objectives, being progressively refined and implemented by State and Territory agencies
- National Action Plan on Salinity and Water Quality - providing a basis for coordinating water quality management activities in some of the key catchments across Australia
- An Audit funded national review of water monitoring in Australia providing a baseline of information for improving monitoring activities (ATECH 2000)
- Review of water quality exceedances and trends: (Australian Water Resources Assessment 2000).
Challenges
To gain maximum return on Australia's investment in water quality monitoring areas of potential improvement that present challenges include:
Monitoring Practices and Activities
- Data standards. Improving data quality by applying more standards and quality assurances particularly to programs such as Waterwatch (where activities are aimed at providing water quality information c/f activities aimed at improving community awareness]
- Enabling trend assessments. Ensuring monitoring programs are maintained for long enough periods and involve sufficiently frequent sampling to support trend analyses at strategically selected sites (with nutrients as a high priority).
- Enabling contaminant load assessments. Ensuring that river flow data is collected and recorded concurrently with contaminant concentration data to allow contaminant loadings to be calculated
- Capturing peak events. Furthering the adoption of flow based water quality monitoring programs to collect contaminant concentration data during a range of flow events to improve contaminant load accounting. This type of monitoring (c/f regular time period monitoring) is more suitable for the variable and extreme flow events that characterise many Australian river systems and which account for much of the contaminant load exported from river catchments to estuaries and near shore environments.
- Better understanding 'natural' water quality. Investing in strategic 'baseline' water quality monitoring programs at less disturbed sites and river basins to improve the understanding of 'natural' system dynamics and provide an improved basis for system specific water quality guidelines
- System relevant monitoring and guidelines. Further implementing basin or region-specific water quality guidelines, and monitoring programs with improved recognition of the natural variability in Australia's surface water quality.
- Responding to basin specific contaminants. Strategically increase the number of variables included in monitoring programs to respond to specific and localised water quality issues such as toxic chemicals (including pesticides), heavy metals and pathogens.
- Assessing water quality outside the intensive land use zone. Establishing water quality monitoring programs in less populated areas of Australia (including the Indian Ocean, Timor Sea, Gulf of Carpentaria and Lake Eyre Drainage Divisions) to assess potential water quality impacts associated with extensive land use areas.
Institutional
- Australia-wide comparability. Within the context of ANZECC water quality and monitoring guidelines (in press), seek agreement on appropriate minimum standards for the range of variables measured, units of measurement and methods so that data Australia wide are comprehensive and comparable
- National monitoring coverage. Supporting and facilitating the implementation of additional water quality monitoring programs so information is available for all key basins, States and Territories.
- Data management and access. Improving data management and access to ensure the community, industry and government have access to quality assured data and information. [An excellent example of data management that facilitates access is the Victorian Water Resources Data Warehouse]
- Reporting and assessment capacity. Continuing Audit type activities so that the national capacity for the regular assessment and reporting of water quality trends is improved and can be more readily linked to land use pattern and practice.
Management
- Managing the drivers of water quality. Translating water quality management objectives into land use planning and management activities that effectively target the causes of water quality impacts
- Monitoring to serve management needs. Designing monitoring programs, sites and data collection activities so that water quality information better serves catchment, river and estuary management needs, quantifying the impacts of catchment land uses and providing feedback for the implementation of Integrated Catchment Management programs, their targets and priorities
- Linking water quantity and quality management. Managing water quantity (diversions, flows and allocations) to better support water quality management objectives
Further Information
- Further information will be made available in the National Water Quality Monitoring Methodology Report once it has been completed.
- Link to data available for download on the Surface Water Management Areas
- Link to data available for download on the Groundwater management units and provinces - ARC/INFO export
- Link to Map Maker.
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New 'Land Use of Australia, Version 3' data showing irrigation, agriculture and landuse for the years 1992, 1993, 1996, 1998, 2000 and 2001 have been added to the Map Maker.
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Australian Water Resources 2005 data has been added to the Map Maker.
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