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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 - Achieving Sustainable Management
The social and economic benefit of Australia?s water resource development has come at a cost to the environment. Water management policies are evolving rapidly and recognise the need to manage systems to also provide for environmental water.
Surface water management
Surface water management is entering a mature phase: economic efficiency, management of the entire resource, equity, and environmentally sustainable practices are key concepts being addressed by Australia?s surface water managers.
Key environmental considerations for improved surface water management are:
Maintenance of environmental flows or water regimes to support in-stream, riparian and floodplain processes, and contribute to biodiversity (e.g. fish breeding, waterfowl habitat and food, triggers for prawn movement in estuaries).
Provision of flushing and dilution flows. This is particularly important in regulated systems, where the natural regime has been substantially altered and the downstream effects of land uses lead to potential water quality problems. Flushing and dilution flows can ensure water quality goals are met (e.g. salinity) and also reduce the release of nutrients-consequently reducing the risk of toxic algal blooms (e.g. blue-green algae blooms).
Conservation of key biodiversity values. Management actions to protect significant in-stream values and biota may need to occur before any decision is made to develop water resources.
Water resource development is approaching or has exceeded extraction limits in the southern States-especially Victoria, New South Wales and South Australia. Development opportunities in south-eastern Australia have shifted from the development of infrastructure to improving water use efficiency. This entails development of more efficient water delivery systems, improving infrastructure and methods of water use, gains through water use efficiency technologies and water trade. There is significant potential for efficiency gains in use within the agricultural sector, particularly through moving to more efficient methods of application such as trickle irrigation and minimising supply system losses to evaporation or seepage. On average only 77% (values range from 41% to 100%) of water diverted for use is delivered to the customer.
Assessment of progress in sustainable surface water management
All States and Territories have established definitions and differing methods to determine sustainable flow regimes for surface water (Appendix 3). Methods recognise the variability of water resources and ecosystems across Australia but are limited in their application by an inadequate knowledge of ecological requirements.
Assessment of progress based on State methods as part of this Audit revealed:
- Thirty-four (10.5%) of Australia's 325 surface water basins are recognised as over-utilised (Appendix 1).
- Forty-three (13.2%) of Australia's 325 basins have been reported to have formal allocations for the environment. The benefits of these allocations to the environment will be assessed over time by monitoring improvements in the ecological health of these systems.
This assessment is based on the methods detailed in Appendix 3.
Figure 29. Surface water management areas. Level of surface water resource commitment (2000)
Figure 30. Surface water management areas in each diversion development category by reliability class (see Appendix 1).
Table 27. Surface water management areas in each nominated diversion development category.
| Number of surface water management areas | Percent of total number of surface water management areas | |
|---|---|---|
| Low development: less than 30% of nominated sustainable flow regime | 195 | 60 |
| Moderate development: between 30% and 70% of nominated sustainable flow regime | 46 | 14 |
| Highly developed: between 70% and 100% of nominated sustainable flow regime | 50 | 15 |
| Overdeveloped: more than 100% of nominated sustainable flow regime | 34 | 11 |
Table 28. Environmental flow allocations for surface water management areas as at June 2000.
| Undetermined | No formal allocation | Less than 33%1 with formal allocation | Less than 67%1 with formal allocation | Total | |
|---|---|---|---|---|---|
| New South Wales | - | 45 | - | 9 | 54 |
| Victoria | 22 | - | 30 | - | 32 |
| Queensland | - | 99 | - | - | 99 |
| Western Australia | - | 42 | - | 2 | 44 |
| South Australia | - | 34 | - | - | 34 |
| Tasmania | 19 | - | - | - | 19 |
| Northern Territory | - | 40 | - | - | 40 |
| Australian Capital Territory | 1 | - | - | 2 | 3 |
| Total | 22 | 260 | 30 | 13 | 325 |
- Percent of sub-catchments within the surface management area.
- Surface water use is negligible-environmental flow allocations are therefore not applicable.
-
Groundwater management
Generally groundwater resources are not as well defined and their management is not as advanced or sophisticated as surface water resources. Implementation levels of best practice groundwater resource management vary. In Western Australia and Queensland, both high users of groundwater resources, knowledge and management of groundwater systems are well developed. In other States (e.g. New South Wales and Victoria), with the limit of surface water supply being reached, demands have substantially increased for access to groundwater resources.
Key sustainability considerations:
Maintenance of water level and/or pressure. Short-term declines of water level and pressure occur with any groundwater development. Ensuring that long-term or unplanned decline does not occur is a key issue in sustainable groundwater management.
Maintenance of water quality. Water quality can be degraded by excessive abstraction flows or intrusions from adjoining aquifers containing saline water, or from land uses that result in contamination.
Determination of environmental water provisions and setting sustainable limits. Sustainable yield needs to be assessed and agreed as a basis for managing the sharing of the resource between consumptive and in situ users.
Progress towards sustainable groundwater management
Broad-scale identification of groundwater resources undertaken as part of the Audit, including the compilation of resource data and definition of the groundwater management units, provides an important baseline for improved management of Australia?s groundwater resources.
Although a concept of sustainable yield has been agreed for groundwater, the basis of the calculation of sustainable yield varies greatly between the States and Territories, with varying degrees of consistency with the emerging approach to sustainable yield (incorporating consideration of all potential demands in the allocation of the resource).
Assessment of groundwater systems against sustainable yield is difficult. Assessment must consider use, allocation and environmental water requirements in the context of resource characterisation. A precise assessment cannot be made for many of the groundwater systems in Australia as characterisation data for groundwater management units are partially or completely lacking.
Based on the methods detailed in Appendix 3, this assessment of sustainability for Australia?s groundwater management units found that:
- Approximately 96% of groundwater management units have use information. 57 (10%) of Australia?s 538 groundwater management units are overused (Appendix 2).
- Three of the groundwater management units in Victoria (less than 1% across Australia) were reported as having formal environmental allocations. However, environmental considerations are known to be part of allocation decisions in other States (e.g. the Swan Coastal Plain wetlands in Western Australia).
Figure 31. Groundwater province abstraction development categorisation (2000)
Figure 32. Groundwater management units in each abstraction development category by reliability class (see Appendix 2).
Table 29. Groundwater management units in each nominated abstraction development category.
Number of groundwater management units Percent of total number of groundwater management units Low development: less than 30% of nominated sustainable yield 274 51 Moderate: between 30% and 70% of nominated sustainable yield 81 15 Highly developed: between 70% and 100% of nominated sustainable yield 104 19 Overdeveloped: more than 100% of nominated sustainable 57 11 Not recorded 22 4 Licence arrangements: differences between allocation and use
Allocation, or rights to use water established under licence, may differ greatly from actual use. On average across Australia, water allocation exceeds use by approximately 11%. However the variation across Australia is significant (Table 30). The differences between allocation and use place particular challenges before water resource managers.
One challenge is the changing status of ?sleepers? (allocations that are not being used) and ?dozers? (allocations that are being occasionally used). Where capping is based on use, we need to recognise water rights while avoiding trading ?sleepers? and ?dozers? where possible. Otherwise, once traded, they become an additional use of the resource.
Through the Audit, Australia has commenced identification and characterisation of over-allocated surface and groundwater systems. For surface water systems, allocation data were able to be provided for 63% of all surface water management areas. Two of these are judged as over-allocated in terms of meeting sustainable flow regimes (Appendix 1).
We have allocation information for approximately 95% of groundwater management units. Eighty-three (15%) of Australia?s 538 groundwater management units are judged to be over-allocated (Appendix 2).
Table 30. Total annual water allocation (GL) in Australia (1996/97).
Surface water allocation (GL) Groundwater allocation (GL) Total allocation (GL) Total water use (GL) Volume difference between allocation and use (GL)1 Percent difference between allocation and use
(%)
New South Wales 9 825 2 665 12 490 10 004 2 486 25 Victoria 5 469 780 6 249 5 788 461 7 Queensland 3 202 983 4 185 4 591 -406 -9 Western Australia 855 1 138 1 993 1 796 197 10 South Australia 740 630 1 370 1 266 104 8 Tasmania2 403 20 423 471 -48 -11 Northern Territory 53 73 126 179 -53 -42 Australian Capital Territory 76 7 83 73 10 12 Total 20 623 6 296 26 919 24 071 2 848 11 1Positive figures indicate where, for the entire State/Territory as a summary analysis, use is less than the amount licenced (allocated); negative figures indicate where use exceeds the amount licensed.
2 All groundwater allocation in Tasmania is informal. Allocation and use information was for 1996/97-the only year for which estimates of water use were made-and a number of rights to water were not defined as volumetric allocations and hence not reported on under allocation. The only allocations reported were those issued as Commissional Water Rights (water licences under the Water Act 1957).
Conjunctive use: a management challenge
Interaction between surface and groundwater systems is an important issue for sustainable water resources management. Some irrigation areas (e.g. Burdekin, Queensland) manage conjunctive use as part of water supply. Nevertheless, administrative arrangements and technical understanding of the complex interactions between surface water and groundwater are still developing for most of Australia. Resource allocation and management decisions are requiring more detailed information of our entire water resources (e.g. as understanding increases, initiatives such as the Murray-Darling surface water cap will probably need to be amended to include conjunctive use).
Sustainable development
Water development is at different stages across Australia. Australian Water Resources Assessment 2000 has identified areas where potential for sustainable development exists. In summary, water resources agencies have identified the following opportunities:
Surface water development
- Australian Capital Territory. Water use is predicted to double by 2050 and a cap on diversion is being set. Any development will result from more efficient water use, particularly in urban use.
- New South Wales. The potential to develop coastal streams will be quantified as flow management plans are developed.
- Northern Territory. Only 0.5% of the sustainable surface water resources are being used and potential for development is high. Implementation of sustainable development of surface water is occurring through the ?beneficial uses? process. The main development need is in augmenting existing water supplies to the Darwin and Greater Darwin areas. In the past, several potential dam sites have been analysed without any consideration for sustainable development.
- Queensland. Water Allocation and Management Plans (WAMP) and Water Management Plans are being completed. The Fitzroy and draft Condamine-Balonne WAMP, Moonie, and Warrego-Paroo-Bulloo-Nebine Water Management Plans have been completed, identifying areas for development while maintaining environmental requirements.
- Tasmania. Private developers have identified a number of sites for irrigation and the State Government is assisting in environmental investigations to assess opportunities.
- Victoria. Very limited opportunities for increases in diversions exist north of the Great Dividing Range. Any new development will be sourced from traded water or from achieving efficiency savings. There is potential for development in south-east Victoria, south of the Great Dividing Range. In the west of the State the resource development is limited by salinity and availability of the resource.
- South Australia. The Mt Lofty Ranges and the more efficient use of Murray River water provide the greatest potential for surface water development.
- Western Australia. Investigations over the last decade have increased knowledge of surface water resource development opportunities in the Indian Ocean Drainage Division. There is still capacity for surface water development while making provisions for the environment in the more populated South-West Division of the State.
Groundwater development
- New South Wales. Potential for groundwater development is limited to aquifers of some of the smaller inland river tributaries and valleys, some of the coastal sand and alluvial aquifer systems and the wider unincorporated areas*.
- Northern Territory. The Northern Territory has a low ratio of current use to available sustainable groundwater resources. Potential for development is limited by environmental values, existing supporting infrastructure, population, land capability and heritage issues. Main opportunity for development is for high return horticultural industries.
- Tasmania. No formal guidelines restricting groundwater development exist and constraints would only occur if groundwater extraction demonstrated an impact on other users.
- Victoria. Approximately one-third of the groundwater management units are highly or fully developed. Potential for groundwater development remains in the south-west of the State, the alluvial systems in the north-east and the South Australian/Victoria border zones in the north and south.
- Western Australia. Around 18% of the State?s groundwater sustainable yield is currently being utilised indicating a significant scope for further groundwater development. The highest level of resource utilisation at the divisional scale occurs in the Perth Basin (39%), which reflects the high accessibility and economic utility of that particular resource. Growth in groundwater use is expected in the Perth groundwater division due to growth in public water systems and self-supplied use for urban, mining and industrial use, as well as growth in the vigorously and generally high value developing irrigation industry on the Coastal Plain. Growth is expected in areas away from Perth and will be dominated by mining development including significant mine dewatering and mining of hypersaline groundwater.
- South Australia. While many of the major groundwater resources are already fully allocated there remains significant unused allocation for development in the State. The majority of the groundwater development potential lies in the south-east of the State and the Murray Basin. However, in these areas soil conditions, salinity and depth to watertable may ultimately constrain some developments. As the large resources are becoming increasingly regulated, other resources (e.g. the Mt Lofty Ranges) are coming under increasing pressure to meet demands for irrigation water. Development pressures are increasingly leading to regulation of the groundwater resources.
Achieving sustainable management
Work is under way in all States and Territories towards sustainable water resources management. Examples of initiatives include:
Environmental, economic, social and engineering assessment criteria for assessing development proposals. Several States are assessing large-scale water resource development proposals using assessment criteria developed by the Audit (e.g. the Tasmanian policy is based on these guidelines for water resource development assessment <www.daff.gov.au/water-reform/publications.html>).
Further development through efficiency gains. Examples include the South Australian Highland Irrigation districts with 15% efficiency gains through infrastructure improvements; piping of part of the Wimmera Mallee stock and domestic system; and the pipelining of the Woorinen supply system in Victoria.
Improved and coordinated management of groundwater. Management of the groundwater resource of the Great Artesian Basin is shared between four jurisdictions and has suffered from lack of coordination in the past-it has tended to be managed as four separate resources. Key issues for management are the continued decline in artesian pressure, the deterioration in the water infrastructure to the point where extractions are substantially in excess of requirements, the difficulty in making water available for new and high-value users, and loss of key groundwater-dependent ecosystems. The recently released Strategic Management Plan provides for its management as a single resource. The plan identifies the need for expansion of joint water users and government bore rehabilitation and a bore drain replacement program (costed at around $220 m) to enable a higher level of control to be exercised over the extractions. Another need is for recovery of artesian pressure to achieve pastoral and biodiversity outcomes, make water available for new users and reduce adverse impacts of water distribution on natural resources and biodiversity.
National Water Reform. All State and Territory water management agencies are working towards meeting requirements for environmental allocations through legislation, planning and assessment processes (e.g. streamflow management plans, stressed rivers programs, riparian vegetation management and nutrient management strategies).
Significant surface water provisions for the environment (e.g. in Western Australia, a State-wide average of 88% of total mean stream flow and 65% of potentially divertible water has been allocated for the environment).
Provisions for groundwater dependent ecosystems. Detailed assessment and formal determination of environmental water provisions has been undertaken for the groundwater areas of the Swan Coastal Plain. This assessment provides for protection of wetlands and sustainable use of a large groundwater resource in the centre of Perth.
Urban demand management. Urban water authorities in all States and Territories have introduced two-part tariffs based on a pay for use principle. It is made up of a service fee and volumetric charge for services. Full cost recovery is also being implemented to yield efficiency gains across most of Australia?s major cities.
Table of Contents for the Australian Water Resources Assessment 2000
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