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In this section you will find detailed information, including national overviews and state and regional level assessments, from the 2000-2002 National Land and Water Resources Audit theme assessments.
Water - Water quality
Water quality improved through coordinated catchment management
Surface water quality
Water quality affects industries as diverse as tourism, fishing and agriculture. Poor water quality heightens water treatment costs for domestic and commercial use, compromises the integrity of aquatic ecosystems and adversely impacts upon biodiversity. The National Eutrophication Management Program reports that freshwater algal blooms alone are costing the Australian community between $180 m and $240 m each year (LWRRDC 2000).
Water quality issues were present in most assessed basins. Turbidity and nutrients were identified as the most widespread water quality issues, followed by salinity and acidity/alkalinity. Better information on the nature and extent of existing water quality problems is fundamental to improving water quality management.
This part of Australian Water Resources Assessment 2000 was undertaken in partnership with the Australian State of the Environment Reporting section of Environment Australia and State and Territory agencies.
Measurement of surface water quality
Monitoring of surface water quality is undertaken to address a range of requirements including:
- protection of public health;
- protection of aquatic ecosystems;
- assessment of waterway condition;
- compliance with discharge licences;
- State of the Environment reporting;
- furthering scientific understanding of catchment processes; and
- identifying relationships between water quality and land management practices.
It has been estimated that Australia spends $142 - $168 m each year on water quality monitoring (ATECH, in press). This monitoring is undertaken by a range of groups and organisations including:
- Commonwealth/regional agencies (e.g. Murray-Darling Basin Commission, Great Barrier Reef Marine Park Authority);
- local and State government agencies involved in environmental monitoring and the regulation of pollution;
- government agencies or government-owned corporations involved in providing services to the community (e.g. water, sewage);
- private companies or organisations whose activities may cause water pollution, often as part of their discharge licensing requirements (e.g. mines, industrial plant operators);
- research groups including universities (e.g. CSIRO); and
- community groups (e.g. WaterWatch).
For the assessment of surface water quality guideline exceedances and trends, data have been provided by all the major State and Territory agency water quality monitoring programs. Data were not able to be obtained from other sources because:
- access to the data is limited by ownership issues;
- access is too costly because of poor database management;
- data are only relevant to a specific area of research interest or licence;
- data collection has involved non-standard procedures; or
- data are of poor quality.
Interpretation of water quality trend data nationally is constrained by the density of data coverage and their availability. Findings are skewed toward States with the most comprehensive monitoring coverage.
Figure 11. Water quality issues. Major water quality issues affecting more than 33% of the river basin.
Note: Datasets for Northern Territory and Tasmania did not meet minimum requirements in terms of sampling frequency and length of monitoring record
Nutrients
Nutrients are a major water quality issue in 43 (61%) of the 70 assessed basins
Australia has a wide range of soil and vegetation types and climatic regimes affecting the natural nutrient status of surface water. State and Territory water quality guidelines reflect this natural variation, the pattern of land use in the catchment and the values of the water resources required to be protected.
The national summary of exceedance of surface water nutrient guidelines indicates that widespread exceedances occur across Australia. They affect the majority 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 are generally the relatively well-vegetated and less developed ones within areas such as north Queensland, north-eastern Victoria and south-western Western Australia.
The availability of data and intensity of monitoring coverage within individual river basins potentially underestimates the extent of nutrient exceedances as a major issue. Monitoring coverage for total nitrogen levels is more limited than that available for total phosphorus levels. Recognising the paucity of data to adequately characterise the nutrient exceedance and trend for Australia, the Audit has commissioned a series of projects that will provide information on the nutrient status of Australia?s catchments, rivers and estuaries. These projects include:
- development of a full nutrient budget for Australia?s intensively developed catchments;
- collaborative work with the Australian fertiliser industry to determine actual use and application rates for fertiliser on farm;
- further data collection and analysis for Australian estuaries; and
- assessment of nutrient impact on Australia?s rivers and estuaries.
These projects will report in 2001 and build on the context provided by this assessment of water quality monitoring data.
Figure 12. Surface water quality 2000. Exceedance of nutrient guidelines. Nutrient exceedances are based on total nitrogen and / or total phosphorus values.
Note: Datasets for Northern Territory and Tasmania did not meet minimum requirements in terms of sampling frequency and length of monitoring record
Figure 13. Surface water quality 2000. Exceedance of total nitrogen guidelines.
Note: Datasets for Northern Territory and Tasmania did not meet minimum requirements in terms of sampling frequency and length of monitoring record
Figure 14. Surface water quality 2000. Exceedance of total phosphorus guidelines.
Note: Datasets for Northern Territory and Tasmania did not meet minimum requirements in terms of sampling frequency and length of monitoring record
Nutrient trend analyses were constrained by the availability of data. The available trend data suggests that:
- six of the basins with exceedances in the Murray-Darling Drainage Division had decreasing nutrient concentration trends, while two basins had increasing nutrient concentration trends;
- six affected basins within the southern Victorian section of the South-East Coast Drainage Division showed increasing nutrient concentration trends, and three basins showed decreasing nutrient concentration trends; and
- one basin in the North-East Coast Drainage Division (Tweed) also showed a clear increasing nutrient concentration trend.
Relative size of basin area, significance of measured values and influence of climatic variation complicate summation of trends. Trend data are best assessed by reference to basin scale reporting through the Australian Natural Resources Atlas.
Figure 15. 'Good' quality surface water total nitrogen guidelines
NSG: No State/Territory guideline establish. ANZECC (1992) guideline was used as the basis for the exceedance assessment. Refer to Table A6 in Appendix 5 for actual values.
Figure 16. 'Good' quality surface water total phosphorus guidelines
* ANZECC (1992) guideline was used as the basis for the exceedance assessment
Salinity
Salinity is a major water quality issue in 24 (32%) of 74 assessed basins-particularly in the temperate South-West Coast, South-East Coast and southern Murray-Darling drainage divisions
Australia?s climate and ancient weathered landscape result in naturally high stores of salt within a range of soil types. Consequently, there are relatively high ?natural? salinity levels in Australian surface waters. This is compounded by the increasing extent of groundwater rise from dryland and irrigation salinity processes as detailed in the Audit?s report on dryland salinity. The State and Territory guidelines reflect these issues.
Salinity in surface water refers to salt concentration and should not be confused with salt load. Stream flow rates may dilute salt concentration so basins can export high salt loads while not exceeding surface water salinity guidelines. This is the case of some basins such as the Murrumbidgee, which exhibit good surface water salinity but export significant salt loads downstream (MDBMC 1999).
The analysis of exceedance of salinity guidelines indicates that salinity is an issue in much of temperate southern Australia and affects basins in the majority 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. Two tropical and several subtropical Queensland basins in the North-East Coast Drainage Division are also assessed to have basin scale salinity exceedances although the skewing of results by tidally influenced monitoring stations was likely for three of these basins.
Basins with no existing ?major? or ?significant? exceedance of salinity guidelines (see Figure 18 for State guideline thresholds) include:
- the majority of coastal basins within the North-East Coast and South-East Coast Drainage Division;
- many of the upper and lower basins within the Murray-Darling Drainage Division; and
- four near coastal basins within the South-West Coast Drainage Division.
The availability of data and the intensity of monitoring coverage limit comprehensiveness of this assessment. Salinity exceedances could also be expected to occur in some basins were there is 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 occurrences of soil salinisation.
Figure 17. Surface water quality 2000. Exceedance of salinity guidelines
Note: Datasets for Northern Territory and Tasmania did not meet minimum requirements in terms of sampling frequency and length of monitoring record
Trend analyses were constrained by available data. Where available, data indicated both increasing and decreasing trends.
- Two affected basins in the South-East Drainage Division showed increasing trends while another two affected basins showed 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 basin trends.
- Within the Murray-Darling Drainage Division at least four 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 (MDBMC 1999) predicts increased salinity for almost all river basins within the Murray-Darling Drainage Division through to 2020, 2050 and 2100. It is important to recognise that the trends identified in Australian Water Resource Assessment 2000 are based on observed river salinity values over the preceeding 8-10 year period. While such trend assessments are important for tracking changes in river salinity they have a limited capacity to predict future salinity values due to 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 Murray-Darling Basin Ministerial Council study (1999) incorporates modelling of groundwater rise and salt load mobilisation processes, and highlights the complexity of developing a predictive capacity for surface water quality.
Figure 18. 'Good' quality surface water salinity guidelines
* Specific guidelines apply for some Victorian basins under State environment protection policies.
** Measured as Total Dissolved Solids (mg/L)
Turbidity
Turbidity is a major water quality issue in 41 (61%) of the 67 assessed basins.
Australia?s variable rainfall and stream flow, and highly erodible soils and streambanks combine to create naturally high turbidity levels in surface waters. To varying degrees State and Territory exceedance guidelines reflect this natural variation, the land use pattern of the basins and the values for which the basins are being managed.
High turbidity levels are a widespread water quality issue in Australia. The affected areas included most inland and lower rainfall basins of the North-East Drainage Division, the majority of the Murray-Darling Drainage Division and the more intensively developed basins of the southern South-East Coast Drainage Division. For some basins, turbidity exceedances may reflect the use of guideline values which do not adequately recognise the naturally turbid conditions of their surface waters. Basins for which exceedance analyses indicated turbidity was not an issue included relatively well forested, less developed and higher rainfall coastal basins within the North-East Coast, South-East Coast and South-West Coast Drainage Divisions. The availability of data and the intensity of monitoring coverage within individual river basins limits this assessment. A lack of monitoring coverage in the Indian Ocean, Timor Sea, Gulf of Carpentaria and Lake Eyre Drainage Divisions limit the ability to assess potential turbidity issues that may be associated with extensive land uses.
Figure 19. Surface water quality 2000. Exceedance of turbidity guidelines
Note: Datasets for Northern Territory and Tasmania did not meet minimum requirements in terms of sampling frequency and length of monitoring record
Recognising the limitations of the monitored data to accurately present the extent of turbidity and soil erosion across the Australian landscape, the Audit has commissioned a series of projects to better define these issues. This includes an assessment of water-borne soil erosion and sediment loads down rivers and estuaries, mapping of sediment types in estuaries, and an assessment of turbidity and sediments as key attributes for both river and estuary health. These projects will report in 2001.
Existing widespread exceedances and predominantly increasing trends suggest that turbidity is a worsening water quality issue for Australia. While constrained by data availability, the majority of trend analyses found increasing turbidity trends.
- In the Murray-Darling Drainage Division at least five affected basins had increasing trends while three affected basins had decreasing basin trends.
- In the South-East Coast Drainage Division at least two affected basins had increasing trends and one affected basin had decreasing trends.
Four basins with no recognised turbidity problems in the southern New South Wales section of the South-East Coast Drainage Division also showed increasing turbidity trends.
Figure 20. 'Good' quality surface water turbidity guidelines
pH
pH is a major water quality issue in 7 (16%) of 43 assessed basins
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 designate ranges for pH values and reflect some of this variability. Ranges are relatively consistent across the country. The monitoring coverage compiled for this variable was primarily limited to Queensland and Victoria. Problems are well documented but not necessarily well monitored in other basins (e.g. acid-drainage water quality problems have been detailed for a number of coastal New South Wales catchments [NSW EPA 1997]).
The areas with major pH exceedances included 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 exhibited significant exceedances of pH guideline.
Exceedances included both acidic and alkaline values, sometimes recorded from within the same basin. Many of the observed pH exceedances are located in coastal basins and may indicate natural floodplain conditions or the disturbance of in situ acid-sulfate soils. The exceedance characterisation of some coastal catchments may be biased by the catchment area weighting of lower basin floodplain/coastal monitoring sites.
Data to support trend analyses were limited to Victoria, Queensland and South Australia. In the Victorian section of the Murray-Darling Drainage Division, analyses identified increasing pH trends (increasing alkalinity) in one basin and decreasing pH trends (increasing acidity) in six basins, only one of which is recognised to have an existing pH exceedance water quality issue. In the South-East Coast Drainage Division, decreasing pH trends were identified in four basins and extensive increasing trends in three basins, all of which do not yet have recognised pH exceedance water quality issues. Two Queensland basins in the North-East Coast Drainage Division also exhibited pH trends-the Brisbane, more acid and the Fitzroy more alkaline. The predominance of decreasing pH (increasing acidity) trends within inland Victoria highlights a need for further investigation. Increasing acidity trends in non-coastal areas could be associated with land degradation processes (e.g. soil acidification) and may be indicative of an emerging surface water quality issue (Harris 2000).
Figure 21. Surface water quality 2000. Exceedance of pH guidelines
Note: Datasets for Northern Territory and Tasmania did not meet minimum requirements in terms of sampling frequency and length of monitoring record
Figure 22. 'Good' quality surface water pH guidelines
NSG: No State/Territory guideline establish. ANZECC (1992) guideline was used as the basis for the exceedance assessment. Refer to Table A6 in Appendix 5 for actual values.
Assessment of State surface water quality
The key water quality problems for Australia are summarised below. State by State detail follows.
Exceedances: Australia
Table 4. Exceedance of water quality guidelines for Australia (number of river basins).
| Major exceedances | Significant exceedances | Number of basins assessed | |
|---|---|---|---|
| Nutrient: total nitrogen | 19 | 19 | 50 |
| Nutrient: total phosphorus | 40 | 20 | 75 |
| Salinity: electrical conductivity | 24 | 18 | 74 |
| Turbidity | 41 | 10 | 67 |
| pH | 7 | 6 | 43 |
Table 5. Availability of trend data.
| Total phosphorus | Total nitrogen | Salinity | Turbidity | pH | |
|---|---|---|---|---|---|
| New South Wales | Y | N | Y | Y | N |
| Victoria | Y | Y | Y | Y | Y |
| Queensland | N | N | Y | Y | Y |
| South Australia | Y | Y | Y | Y | Y |
| Western Australia | Y (limited) | Y (limited) | Y | N | N |
| Australian Capital Territory | Y | Y | Y | Y | Y |
Exceedances: New South Wales
Table 6. Exceedance of water quality guidelines for New South Wales (number of river basins, total = 34).
| Major exceedances | Significant exceedances | Number of basins assessed | |
|---|---|---|---|
| Nutrient: total nitrogen* | 1 | 2 | 3 |
| Nutrient: total phosphorus | 16 | 7 | 27 |
| Salinity: electrical conductivity | 2 | 5 | 16 |
| Turbidity | 11 | 4 | 21 |
| pH | 0 | 2 | 2 |
* ANZECC (1992) guideline was used for the exceedance assessment
Nutrient exceedances in New South Wales were assessed in terms of total phosphorus. They occurred in both inland and coastal regions. In the Murray-Darling Basin, nutrient exceedances often occurred with and would appear to be related to turbidity exceedances. Increasing trends in phosphorus were identified for a number of basins both coastal (Tweed, Macquarie-Tuggerah Lakes) and inland (Macquarie-Bogan). Decreasing phosphorus trends were observed for three inland basins (Murray-Riverina, Upper Murray, Namoi) and one coastal basin (Clarence).
Salinity exceedances were not widely recorded within New South Wales. Chronic exceedances were recorded within the Murray-Riverina basin and to a lesser extent within other Murray-Darling basins. Observed salinity trends are predominantly remaining steady or decreasing. Several of the Murray-Darling basins (Lachlan, Murray-Riverina, Namoi) showed decreasing salinity trends. Basins with increasing trends included the Manning Basin and the Horton River within the Gwydir Basin.
Turbidity exceedances are widespread throughout inland New South Wales. They include most basins within the Murray-Darling Drainage Division but are less prominent in coastal New South Wales with exceedances only being recorded in three basins (Hawkesbury, Macquarie-Tuggerah Lakes, Hunter). However inland rivers typically have finer sediments and often higher natural turbidity than coastal rivers. Increasing turbidity trends were observed for basins with existing turbidity exceedance issues (Macquarie-Bogan) and a number of southern coastal basins lacking existing turbidity problems (Clyde, Bega, Towamba). Two inland basins (Namoi, Gwydir) also showed decreasing turbidity trends. New South Wales trend analyses were based on a seven year record.
Very limited surface water acidity/alkalinity data were able to be compiled for New South Wales.
Exceedances: Victoria
Table 7. Exceedance of water quality guidelines for Victoria (number of river basins, total = 29).
| Major exceedances | Significant exceedances | Number of basins assessed | |
|---|---|---|---|
| Nutrient: total nitrogen | 17 | 6 | 25 |
| Nutrient: total phosphorus | 18 | 4 | 25 |
| Salinity: electrical conductivity | 8 | 6 | 21 |
| Turbidity | 17 | 2 | 23 |
| pH | 1 | 1 | 19 |
Water quality monitoring in Victoria is more intensive and has a greater coverage than in any other State. Water quality is generally ?fair? across the State with a majority of basins continually exceeding guideline values for turbidity, total nitrogen and phosphorus concentrations. Only two less developed basins in the east of the State (Snowy, Mitchell) did not record exceedances for both nitrogen and total phosphorus. Victorian nutrient exceedance guidelines are under review and may be relaxed for nitrogen levels to better reflect the variability of the surface waters. Nutrient trend analyses were limited by the length of available datasets but where available, tended to indicate decreasing total nitrogen trends for northern and eastern basins and increasing trends for a number of south coast basins (e.g. Hopkins, Tambo, South Gippsland). A mixture of up and downward trends was observed for total phosphorus. South coast basins (e.g. Portland coast, Hopkins, Otway, South Gippsland) showed upward trends while the Latrobe and the Maribyrnong showed downward trends.
A significant portion of the Victorian basins obtained poor exceedance results for salinity, including most western basins in the Murray-Darling and South-East Coast Drainage Divisions. Four of these basins also showed increasing salinity trends while basins in the central north and south (Maribyrnong, Barwon, Campaspe, Latrobe) showed decreasing trends in salinity.
Turbidity exceedances were widespread across Victoria with only eastern basins (Latrobe, Thomson, Mitchell, Snowy) showing good results. Turbidity trends indicated an increasing pattern in several basins within the Murray-Darling Drainage Division in the north and within the Maribyrnong and South Gippsland basins in the south of the State. Decreasing trends were observed in the Latrobe and Wimmera-Avon basins.
Only a few basins exhibited acidity/alkalinity guideline exceedances (e.g. Campaspe, Wimmera-Avon, Thomson). However strong state-wide trends for increasing acidity were recorded for most eastern basins while several central southern basins recorded increasing trends for alkalinity.
Exceedances: Queensland
Table 8. Exceedance of water quality guidelines for Queensland (number of river basins, total = 69).
| Major exceedances | Significant exceedances | Number of basins assessed | |
|---|---|---|---|
| Nutrient: total nitrogen | 5 | 4 | 11 |
| Nutrient: total phosphorus | 4 | 5 | 15 |
| Salinity: electrical conductivity | 2 | 4 | 16 |
| Turbidity | 11 | 4 | 18 |
| pH | 6 | 3 | 18 |
Turbidity and nutrients are the dominant water quality issues within Queensland. Most North-East Coast Drainage Division basins, particularly larger inland extending basins, recorded turbidity exceedances. Several smaller, relatively well vegetated coastal basins (e.g. Russell-Mulgrave, Johnstone, Pioneer) did not have turbidity exceedances. The distribution of nutrient exceedances, particularly total phosphorus, parallels turbidity. Basins without phosphorus exceedances included the Herbert, Tully, Pioneer and Burnett. Data for total nitrogen were less extensive but showed that some basins without exceedances for total phosphorus did have total nitrogen exceedances (e.g. Herbert). Insufficient data were available to assess nutrient concentration trends.
Queensland does not suffer the major salinity problems experienced in other States. However, trend results have identified that some basins are undergoing changes to the salinity regime, with the Burdekin and Condomine-Balonne both recording increasing salinity trends. The inclusion of lower basin tidally influenced sampling sites in the exceedance analyses is thought responsible for all basins that recorded salinity exceedances including the Daintree, O?Connell, Kolan, Burrum, Brisbane and Logan-Albert basins.
Acidity/alkalinity exceedances were recorded for a number of coastal Queensland basins. In several instances these included relatively undisturbed basins (Endeavour, Daintree), and may reflect the naturally acidic conditions of lowland floodplain surface waters. Other basins recording exceedances (Russell-Mulgrave, Tully, Herbert, Ross, O?Connell, Burrum) have relatively intensive floodplain development and modification. Acidity could be associated with disturbance of acid-sulfate soils.
With the exception of two sites in Oxley Creek in the Brisbane Basin, faecal coliforms are not routinely monitored in Queensland waterways.
Exceedances: Western Australia
Table 9. Exceedance of water quality guidelines for Western Australia (number of river basins, total = 44).
| Major exceedances | Significant exceedances | Number of basins assessed | |
|---|---|---|---|
| Nutrient: total nitrogen | 2 | 3 | 7 |
| Nutrient: total phosphorus | 1 | 4 | 7 |
| Salinity: electrical conductivity | 11 | 2 | 17 |
| Turbidity* | 2 | 0 | 3 |
| pH | 0 | 1 | 3 |
* Measured as total suspended solids (mg/L)
Available nutrient data indicated that exceedances-both total phosphorus and total nitrogen-were significant water quality issues in most monitored basins. Only the Blackwood basin did not exceed guidelines for both total nitrogen and total phosphorus. The Preston basin reported exceedances for total nitrogen but not phosphorus, while the Murray basin did not exceed guidelines for total nitrogen but did for total phosphorus-possibly associated with its high turbidity status (phosphorus can be bound to suspended sediment). Trend data indicated increasing nutrient trends for the Denmark (total nitrogen), and for Murray and Harvey (total nitrogen and total phosphorus) basins. Small areas of decreasing trends were also observed for the Murray, Albany (total phosphorus) and Swan Coastal basins (total nitrogen and total phosphorus).
Salinity was identified as the most widespread surface water quality issue in Western Australia. This may partially reflect the limited data collected on other water quality variables. Except for some smaller coastal basins in the South-West Drainage Division (Harvey, Preston, Donnelly, Shannon) almost all basins-both inland and coastal-were affected by salinity. Trend data identified a relatively large number of basins with increasing salinity trends (Kent, Frankland, Warren, Busselton, Murray, Esperance, Shannon). Some parts of the Shannon basin recorded decreasing trends. The Preston also recorded decreasing salinity trends.
Turbidity data were available for analysis from only four basins. They indicated that the Murray and Harvey Basins had significant exceedances while the Blackwood basin did not.
pH data were also limited. Only one basin (Harvey) had recorded exceedances.
Exceedances: South Australia
Table 10. Exceedance of water quality guidelines for South Australia (number of river basins, total = 21).
| Major exceedances | Significant exceedances | Number of basins assessed | |
|---|---|---|---|
| Nutrient: total nitrogen | 2 | 3 | 5 |
| Nutrient: total phosphorus | 3 | 1 | 4 |
| Salinity: electrical conductivity | 1 | 2 | 4 |
| Turbidity | 2 | 1 | 3 |
| pH | 0 | 0 | 1 |
Only a limited number of South Australian river basins have sufficient monitoring coverage to support basin water quality exceedance and trend assessments. Therefore some reference is made to monitoring station results.
The best basin monitoring coverage available was for nutrients and recorded total nitrogen and/or total phosphorus exceedances for the Lower Murray, Mallee, Myponga, Fleurieu Peninsula and Willochra Creek basins. Individual site nutrient exceedances were recorded from all monitored basins.
Significant and major salinity exceedances at a basin scale were recorded for the Myponga, Fleurieu Peninsula and Willochra Creek basins. However, salinity exceedances were recorded for monitoring stations from all basins indicating the widespread nature of salinity as a water quality issue in South Australia. Although tributaries of the Lower Murray Basin recorded large exceedances of salinity guidelines these tributaries occupy only a small area of the Lower Murray Basin. Trend analyses of observed salinity values for the Lower Murray Basin indicated a decreasing trend in salinity.
Basin turbidity exceedances were recorded for the Lower Murray, Mallee and Fleurieu Peninsula. Individual monitoring station exceedances were also recorded from the Broughton, Torrens and Millicent Coast basins. Trend data indicated increasing turbidity within the Mallee and Lower Murray basins.
Only the lower Murray had basin monitoring coverage for pH, which indicated no significant basin exceedances for this variable. A monitoring station pH exceedance was recorded for Lake Alexandrina.
Exceedances: Australian Capital Territory
Table 11. Exceedance of water quality guidelines for the Australian Capital Territory (number of monitoring stations1).
| Major exceedances | Significant exceedances | Number of monitoring sites assessed | |
|---|---|---|---|
| Nutrient: total nitrogen2 | 5 | 0 | 5 |
| Nutrient: total phosphorus | 0 | 5 | 5 |
| Salinity: electrical conductivity | 0 | 5 | 5 |
| Turbidity | 2 | 3 | 5 |
| pH | 0 | 5 | 5 |
| Faecal coliforms | 3 | 2 | 5 |
- Results presented here are for individual monitoring stations because the Australian Capital Territory lies within one river basin (Murrumbidgee).
- ANZECC (1992) guideline was used as the basis for the exceedance assessment.
-
Water quality within the Australian Capital Territory is generally within guideline values. Main exceptions are sites that have direct run-off from urban development, showing elevated total nitrogen, turbidity and faecal coliforms. Land use and development impacts are shown particularly in the Molonglo River sites. Total nitrogen values downstream of the Australian Capital Territory are high due to the discharge of treated waste water effluent high in nitrate.
Trend analyses for all attributes indicated an increasing trend in faecal coliforms in the Murrumbidgee River downstream of the Australian Capital Territory.
Groundwater quality
Water quality data for groundwater are limited. A review of the salinity status of groundwater revealed that approximately 21 000 GL (72%) of Australia?s readily accessible groundwater supply is suitable for drinking water*.
Figure 23. Proportion of groundwater sustainable yield (GL/year) by salinity class
Table 12. Groundwater sustainable yield (GL) by salinity status (mg/L).
<500 500-1000 1000-1500 1500-3000 3000-5000 5000-14000 >14000 Total NSW 554 4 237 129 790 480 - - 6 189 VIC 302 422 244 367 207 1 377 797 3 717 QLD 1 422 1 030 113 160 35 23 - 2 784 WA 514 1 162 1 150 1 500 766 841 371 6 304 SA - 290 709 102 21 25 - 1 146 TAS 1 585 767 - 178 - - - 2 531 NT 5 785 186 324 141 5 - - 6 441 ACT 103 - - - - - - 103 Total 10 264 8 094 2 670 3 238 1 515 2 266 1 168 29 215 Percent of groundwater resource 35 28 9 11 5 8 4 100 Achievements in water quality management
Australia has:
- implemented a National Water Quality Management Strategy (ANZECC/ARMCANZ 1994);
- prepared National Water Quality Guidelines (ANZECC, in press);
- prepared National Guidelines for Water Quality Monitoring and Reporting (ANZECC, in press);
- initiated a National Action Plan for Salinity and Water Quality (Commonwealth Government 2000) providing a basis for coordinating water quality management activities in some key catchments;
- conducted an Australia-wide review of water monitoring to provide baseline information for improving monitoring activities (ATECH, in press); and
- reviewed water quality exceedances and trends (Australian Water Resources Assessment 2000).
Table of Contents for the Australian Water Resources Assessment 2000
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