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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 - Assessment 2000: an overview
In 1994 the Council of Australian Governments agreed that action was needed to maximise the net value of the use and existence of the water resource and move to increase financial viability of the water industry. In addition it was needed to stop widespread degradation of natural resources and to minimise unsustainable use of water resources. They agreed to a strategic basis for action-the National Water Reform Framework-with the provision of water for the environment a key principle. Establishing environmental water provisions requires a multidisciplinary approach and is being undertaken with varying levels of sophistication across Australia.
Water reporting units
Australian Water Resources Assessment 2000 defined 325 surface water management areas and 538 groundwater management units as a basis for reporting on water quantity, use and allocation.
Surface water management areas refine the Australian Water Resources Council river basin definitions to better reflect the increasing need to intensively manage surface water systems.
For the first time, Australia has a spatially defined set of groundwater management units, an important basis for improved groundwater management.
Some 61 broadly defined groundwater provinces (defined by the former Australian Water Resources Council) have been used in this report as an aggregation unit for map representations of groundwater management data because groundwater management units can overlie each other and therefore cannot be represented in a compilation map form (see Figure 4b).
The 12 drainage divisions and 246 component river basins were defined by the former Australian Water Resources Council and have been used to present the results of the surface water quality assessment-with the exception of the Australian Capital Territory where monitoring stations have been used as the basis for reporting.
Table 1. Australian Water Resources Assessment 2000 reporting units.
| Groundwater1 management units | Surface water management areas | River basins2 | |
|---|---|---|---|
| New South Wales | 50 | 54 | 34 |
| Victoria | 79 | 32 | 29 |
| Queensland | 107 | 99 | 69 |
| Western Australia | 174 | 44 | 44 |
| South Australia | 53 | 34 | 21 |
| Tasmania | 17 | 19 | 19 |
| Northern Territory | 55 | 40 | 30 |
| Australian Capital Territory | 3 | 3 | n/a |
| Total | 538 | 325 | 246 |
1 Include the apportionment of the Great Artesian Basin components for each State or Territory.
2 In Water Review ?85 (DPIE, 1987) groundwater data were presented on a river basin basis.
Figure 1. River Basins
Click here to view the list of River Basins in Australia
Click here to download and view map in.pdf format (398 kb)
Figure 2. Surface Water Management Areas
Click here to view the list of Surface Water Management Areas in Australia
Click here to download and view map in.pdf format (452 kb)
Figure 3. Groundwater provinces
Click here to view the list of Groundater Provinces in Australia
Click here to download and view map in.pdf format (507 kb)
Figure 4a. Australia's groundwater management units
Figure 4b. Groundwater management units in the Port Phillip Groundwater Province
- A = Merrimu
- B = Deutgam
- C = Morrabin
- D = Frankston
- E = Nepean
- F = Jan Juc
- G = Port Phillip - water table aquifer
- H = Cut Paw Paw
- I = Port Phillip - middle Teritary aquifer
- J = Port Phillip - lower Tertiary aquifer
|
Average relative depth: 5 metres  |
Average relative depth: 20 metres  |
|
Average relative depth: 30 metres  |
Average relative depth: 50 metres  |
|
Average relative depth: 60 metres  |
Average relative depth: 100 metres  |
Groundwater management units
This map (Figure 4a) is provided to show the broad distribution of groundwater management units across Australia. In some cases groundwater management units overlie each other (e.g. in the Port Phillip Province, see Figure 4b).
Unincorporated areas
An unincorporated area is a groundwater resource defined by a groundwater province and excluding any designated groundwater management units. For the purposes of reporting the total groundwater resource, unincorporated areas have been included in the analyses that follow. For convenience unincorporated areas are reported as and under the heading of groundwater management units.
Water availability
Australian Water Resources Assessment 2000 details our water resources, reports on the sustainability of surface water and groundwater resources. It compares nominated sustainability measures to the allocation, current use and degree of infrastructure development in 325 surface water management areas and 538 groundwater management units.
The determination of a measure for sustainable water use requires consideration of a complex set of biophysical interactions and social and economic demands. It involves a trade-off between maintenance of in situ ecological values and demands for water extraction. This is made more complex in that the allocation under licence may differ from the actual use. A system in which use patterns exceed the designated sustainable measure is deemed to be over-utilised. Where the water allocation pattern exceeds a designated sustainable measure, there is a potential for overuse.
A technical review of methods for establishing environmental water provisions was undertaken as part of the Audit?s assessment (Appendix 3). Each State/Territory used methods to assess sustainability within the context of its water management programs (e.g. Water Allocation Management Planning [Queensland], the Bulk Entitlement Conversion Program [Victoria], Stressed River Assessment Reports [New South Wales], the Water Management Planning Program [Tasmania] and the Water Allocation Program [Western Australia]).
Specific concepts of ?sustainable flow regimes? for surface water and ?sustainable yield? for groundwater were adopted for this assessment to:
- provide a comparable analysis across Australia;
- identify priority areas for further investigation or management action; and
- communicate Australia?s progress towards sustainable water resource management.
Research on ecological requirements of rivers is progressing. Australian Water Resources Assessment 2000 represents the best available knowledge and its application by State and Territory water management agencies.
Key elements of the National Water Reform Framework
- Pricing based on principles of full cost recovery and removal (or transparency) of cross subsidies.
- Future investment in new irrigation schemes, or extensions to existing schemes, to be undertaken only after appraisal indicates it is economically viable and ecologically sustainable.
- Comprehensive systems of water allocations or entitlements; backed by separation of water property rights from land, and clear specification of entitlements in terms of ownership, volume, reliability, transferability and, if appropriate, quality.
- Formal determination of water allocations or entitlements, including allocations for the environment as a legitimate user of water.
- Trading, including cross-border sales, of water allocations and entitlements, within the social, physical, and ecological constraints of catchments.
- Providing an integrated catchment management approach to water resource management including water quality.
- The separation of resource management, standard setting and regulatory roles of government, from the role of providing water services.
- A greater degree of responsibility for local management of irrigation areas.
- Public education about water use and consultation in implementing the water reforms.
- Appropriate water related research and use of efficient technologies.
Source: High Level Steering Group on Water, September 1999
Categorisation
A four-class classification system was developed to provide a simple method to communicate the status of the use and allocation of Australia?s water resources.
| Category | Extraction/ allocation1 % | Development status |
|---|---|---|
| 1 | <30 | Low development |
| 2 | 30-70 | Moderate development |
| 3 | 70-100 | Highly developed |
| 4 | >100 | Overdeveloped |
1Water extraction (diversion for surface water or abstraction for groundwater) and/or allocation as a percentage of the sum of sustainable flow regime (surface water) and sustainable yield (groundwater).
Category 1 systems have zero to low levels of resource use: direct management intervention and information requirement are low (e.g.2 Victoria River, Northern Territory; Burnie, Tasmania).
Category 2 systems are moderately developed: management and resource information requirement is moderate (e.g.2 Broughton River, South Australia; Ti Tree, Northern Territory).
Category 3 systems are close to, or at, their extraction limit and require a high level of management inputs. Resource information and monitoring are vital for these systems. Development depends on installation of appropriate water markets to move water to higher value use and to provide surplus for development or the environment through efficiency gains (e.g.2 Pioneer River, Queensland; Woongarra, Queensland).
Category 4 systems are over-committed in water allocation and/or use: insufficient provision has been made for environmental and non-consumptive uses, management intervention and information requirements are substantial (e.g.2 Wimmera-Avon Rivers, Victoria; Neuarpur GSPA, Victoria).
As the level of use nears or exceeds estimates of sustainable yield, higher levels of management are required. This will often require additional and more detailed information.
2Surface water example is given first, followed by a groundwater example
Surface water
The working definition of sustainable flow regimes adopted by this assessment was:
The limit on potentially divertible water that will be allowed to be diverted from a resource after taking account of environmental values and making provision for environmental water needs.
The concept of sustainable flow regimes needs to allow for the frequency of high, low and seasonal flow requirements of in-stream, wetland and floodplain environmental use and reliability of supply for extractive users. Methods of estimation across the States and Territories vary (Appendix 3).
Groundwater
The working definition of sustainable yield adopted for this assessment in 1998 for groundwater systems was:
The level of extraction measured over a specified planning timeframe that should not be exceeded to protect the higher value social, environmental and economic uses associated with the aquifer.
As part of and to underpin this definition, it was agreed by the State and Territory agencies, that for Water Resources Assessment 2000, operationally this definition would be interpreted as groundwater use being sustainable where groundwater level and pressure was maintained. Methods of estimation across the States and Territories vary (Appendix 3).
Update on progress
In May 2000 as part of the continued development of sustainability concepts, the National Groundwater Committee (a working group of the Sustainable Land and Water Resource Management Committee) agreed on the following definition of ?sustainable yield? and has submitted it to the High Level Steering Group on Water for endorsement:
The groundwater extraction regime, measured over a specified planning timeframe, that allows acceptable levels of stress and protects the higher value uses that have a dependency on the water.
The States have used a broad range of approaches to implement sustainable yield. The principal method considers a percentage of the assessed rainfall-commonly between 1% and 5%-as being the recharge. Sustainable yield is then defined as all or the majority of the recharge. Other hydrogeological criteria and approaches have also been adopted to suit specific circumstances.
It was generally agreed by the State and Territory agencies, that groundwater level and pressure should be maintained at predetermined levels, while acknowledging that ?storage depletion? may occur.
Water requirements of groundwater-dependent environmental factors are significant in assessing sustainable yield. The extent to which environmental water provision has been taken into account for sustainable yield varies considerably between the States and Territories. River baseflow and wetlands requirements have often been considered to a rudimentary extent; vegetation and most other groundwater-dependent environmental factors have not been considered. As knowledge and appreciation of groundwater-dependent environmental factors increases, methods for calculating sustainable yield will be refined and values may decrease from present estimates.
Water quality
Australia Water Resources Assessment 2000 provides the first overview of Australia?s declining surface water quality with salinity, nutrients and turbidity issues revealed across most of the intensively used basins. Assessments of blue-green algae blooms, acidity/alkalinity and contamination by faecal coliforms have also been compiled where data are available (see the Australian Natural Resources Atlas).
Data coverage available for each variable is broadly related to both the perception of water quality data needs or problem areas and the ease and expense involved in measuring the particular variable. Variables with the greatest coverage are salinity, followed by turbidity, total phosphorus, pH and total nitrogen. Faecal coliform data were only available for a small number of sites within Queensland and the Australian Capital Territory. Data from local government and corporatised service providers-which often have prime responsibility for the monitoring of surface waters from a human health perspective-were not accessed.
The assessment has been based on comparing collated data with State and Territory guidelines for ?good? water quality. These guidelines take account of the natural variation in Australia?s surface water characteristics, the intensity of water quality impacting land uses, and the management objectives for the particular water body. Basin area characterisations were achieved by using a catchment area weighting method in which the results of a monitoring station were weighted by the area of river basin it sampled (Appendices 3 & 5). This method was supported and adopted by State and Territory agencies when compiling the assessment and can be rationalised in terms of the way water quality reflects land use activities in a basin. Nevertheless, the potential for generation of error was recognised, particularly when the monitoring coverage across a basin is limited and the opportunity for bias in the characterisation of basin water quality increases. This may lead to underestimation of the extent of declining water quality issue where monitoring stations are not placed in impacted areas, or alternatively overestimation of declining water quality where in the absence of upstream monitoring stations, results obtained by impacted lowland sites are used to characterise the upper basin.
In this Assessment monitoring sites were classified as ?good?, ?fair? or ?poor? for each variable based on whether guidelines were met. Generally a ?good? classification was achieved where water quality was within guidelines for a majority of time while a ?poor? classification resulted where water quality did not meet the guidelines for a greater period of time. A range of statistical measures including the median, ninetieth percentile, and percent time exceedance were used by States and Territories for this determination. These were dependent on the variable and whether the analysis was based on assessing acute (short-term extreme event) or chronic (long-term sustained event) water quality impacts. Full discussion of the methods used for water quality exceedance and trend assessment are presented in the A review of Australia?s surface water quality (ASoE & Audit, in prep.)
To compile the Australia-wide overviews of exceedances of ?good? water quality guidelines within basins a number of rationalised thresholds were used:
- ?major? issues occurred where guideline exceedances were calculated to occupy greater than a third (33%) of the basin area;
- ?significant? issues occurred where guideline exceedances were calculated to occupy greater than 5% but less than 33% of the basin area;
- ?undetermined? issues occurred where monitoring coverage was less than 50% of the basin area, and observed guideline exceedances represented less than 5% of the basin area.
- ?not significant? issues occurred where monitoring coverage was greater than 50% of the basin area and observed guideline exceedances represented less than 5% of the basin area.
The water quality assessment is constrained by available monitoring data. Data for each variable ranged from between 43 and 75 basins. No assessments were possible for Tasmania or the Northern Territory, or for Australia?s less intensive land use areas including the Indian Ocean, Timor Sea, Gulf of Carpentaria and Lake Eyre drainage divisions because the water quality datasets did not meet the minimum requirements in terms of frequency of sampling or duration of monitoring record.
Data are limited to the more developed areas of Australia. The areas of greatest data availability include most of the North-East Coast, South-East Coast, Murray-Darling and South-West Coast Drainage Divisions. The South Australian Gulf Drainage Division has only limited monitoring coverage. In terms of State coverage, Victoria is best served followed by New South Wales, Queensland and Western Australia.
To facilitate more detailed assessment beyond the basin aggregations presented in this report, site data are reported in the Australian Natural Resources Atlas. This builds on initiatives such as the Victorian Water Resources Data Warehouse and will be invaluable to regional groups seeking to understand water quality issues and priorities within their basin.
Table 2. River basin water quality data analysis coverage for different water quality variables. Percent figures indicate proportion of Australia?s 246 basins.
| Water quality variable | River basins with sufficient data for site exceedance assessment1 | River basins with sufficient data for site trend assessment2 | |||
|---|---|---|---|---|---|
| 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% | |||
Criteria for inclusion of data in Australian Water Resources Assessment 2000:
- 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 taken.
-
Water quality trends
Water quality trend data were limited by the lack of monitoring sites with adequate long-term records. There are generally sufficient salinity data to assess trends in most of the more intensively developed catchments and a relatively good coverage of turbidity data for trend analyses in the intensive land use areas. Victoria is the only State that monitors both nitrogen and phosphorus with sufficient frequency to provide data across the State on which good trend analysis can be undertaken. Trend information that is available is detailed in the Australian Natural Resources Atlas, again as a basis for regional resource management.
Stringent data quality and length of record requirements needed to be met to enable defensible exceedance and trend analyses to be conducted (ASoE & Audit, in prep.). These requirements further reduced the amount of water quality data available for this assessment. A tabular summary of river basin coverage and data meeting criteria for inclusion in this assessment for each water quality variable is presented in Table 2.
Water quality variables examined as part of the Audit surface water quality assessment
Water quality variables that were examined as part of the Audit surface water quality assessment include:
Salinity describes the salt concentration in water. Usually measured as electrical conductivity of water in microsiemens per centimetre (µS/cm-sometimes referred to as EC units). Electrical conductivity is an appropriate indicator of salinity, as it is proportional to the concentration of total dissolved salts and is easily measured in the field or by later laboratory analysis. Salinity is also sometimes measured directly (as is the case in Western Australia) as total dissolved solids.
Turbidity is a measure of the clarity, ?dirtiness? or light scattering/absorbing capacity of water, which is roughly proportional to the type and concentration of suspended matter. It is therefore commonly used as an indicator of the amount of suspended solids in the water column. Turbidity is usually measured in Nephelometric Turbidity Units (NTU), which provide a measure of the capacity of light to penetrate through water. Total suspended solids measured in milligrams per litre (mg/L) is also used as a less accurate measure of turbidity in some instances and by some States although it is recognised that non-solid or dissolved substances within water can also affect turbidity.
Nutrients. There are a number of nutrients that affect the quality of surface waters. These include nitrogen, phosphorus and organic carbon. These nutrients can occur in a range of chemical forms. Total nitrogen and total phosphorus were assessed as part of the Audit.
Total nitrogen is a measure that sums the concentration of the major forms of nitrogen including ammonia, organic nitrogen, nitrate and nitrite. Total nitrogen is reported in milligrams per litre (mg/L) and requires laboratory analysis of samples collected in the field for accurate measurement.
Total phosphorus is a measure that sums the concentration of all forms of phosphorus in the water column including dissolved forms, insoluble particulate forms and phosphorus already incorporated in phytoplankton. Total phosphorus is measured in milligrams per litre (mg/L) and requires laboratory analysis of samples collected in the field for accurate measurement.
pH is a measure of the concentration of free hydrogen ions in solution. It is expressed on a logarithmic scale (1-14). Values at the low (1-7) end of the pH scale represent extreme to low acidity, while values at the high (7-14) end of the pH scale are a measure of low to extreme alkalinity; 7 in the middle of the scale indicates a neutral solution.
Faecal coliforms are bacteria present in human and animal waste. Measures of faecal coliform concentration are obtained by cell counts using epifluoresence (measures the brightness of ultra violet illuminated bacteria in water samples) or by the use of standard sized sampling plates. Counts provide an indication of the contamination of water by sewage or animal wastes and the suitability of water for drinking.
Other surface water quality issues include blue-green algae blooms, 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 was not able to be assessed. In the case of blue-green algae it was assessed but due to the paucity of data, has not been reported (see A review of Australia?s surface water quality [ASoE & Audit, in prep.]).
Table of Contents for the Australian Water Resources Assessment 2000
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