Water availability in New South Wales
New South Wales overview
Water is a fundamental requirement for New South Wales' economic growth, its natural ecology and the community's life style and values.
- It is a major input to regional economic growth through agriculture, mining and associated industries. Currently 20-30% ($1.5-2 billion) of NSW gross value of agricultural production comes from irrigation.
- Good quality and reliable water is a fundamental need for the health and wellbeing of the 6.5 million people in NSW. Currently some 22 major storages (capacities greater than 10 GL) are used to supply drinking water to NSW urban centres and a further 17 major storages are used to supply water for irrigation.
- The existence of rivers is an important feature of many of the over 480 National Parks and Reserves in New South Wales and the availability of flow that closely follows natural patterns is critical for NSW's 4.5 million hectares of wetlands. Ninety four of these wetlands have been identified in the directory of important wetlands in Australia and of these, 6 have been identified as wetlands of international importance or RAMSAR sites.
In 1995 NSW embarked on a major program of water reform. The reforms have three goals:
- To better share the available water - by balancing the needs of consumptive water users with the need to maintain a sustainable ecosystem
- To enhance support to the rural sector - by recognising that a secure water future is essential to maintaining a productive rural sector.
- To reshape how water is managed and delivered in NSW - by providing avenues for direct community involvement in water management decisions and processes.
NSW is in the midst of implementing the reform initiatives. A key element of the change is the decision to provide an environmental flow share over the full range of flows in rivers. NSW adopted this approach as it considered that environmental flow shares could not be confined to low flows if the needs of the Australian water ecology are to be adequately addressed. Rather, NSW has used a range of hydrologic measures other than average or median flows to adequately reflect the unique features of Australian stream-flow. NSW is in the process of developing many of the initiatives and they are utilising a significant portion of government resources. As a result some of the reporting requirements of the National Land and Water Resources Audit cannot be fully met at this stage. Investigations are underway to see if, as the valley specific initiatives in the State are completed, the relevant information can be added to the Atlas.
The NSW Water Reform environmental flow strategies for the inland basins include the requirements of the Murray Darling Basin Commission (MDBC) cap, which limits water use to the level of development that was achieved in 1994. In fact in the inland basins, the Water Reform initiatives will reduce usage below the cap level in many valleys. Potential for development in the inland basins will therefore be limited to that facilitated by water trading or efficiency gains within the user enterprise. For these reasons, users of the Atlas will notice that all management areas within the Murray Darling basin in NSW are shown to have developed yields beyond sustainable levels. Furthermore identification of the surface water development potential on the NSW coastal streams will not possible until such time as flow management plans are developed for each of the coastal valleys.
The main constraint to development of groundwater resources is the extent to which they have already been developed. Allocations in most of the more productive aquifers have already reached or exceeded the estimate of sustainable yield. Constraints to development of other areas are mainly the uncertainty about sustainable yield, the limit to the magnitude of individual bore supplies imposed by the physical characteristics of the aquifer formation and quality of the water. The potential for further development of groundwater resources is in general limited to some of the smaller inland river tributary valleys, some of the coastal sand and alluvial aquifer systems, and the wider areas of the unincorporated areas.
There are 43 AWRC defined river basins in New South Wales and 17 of the 21 basins west of the divide form part of the Murray Darling Basin. On the basis of review done for the Audit all 17 of the basins in the Murray Darling are over committed (use exceeds sustainable yield). Likewise 2 of the 49 groundwater management units (including unincorporated areas) are over committed based on current usage and a further 17 are overcommitted based on allocation.
The key elements of NSW compliance with the principles established in the national water reform agenda include:
- Establishment of the Independent Pricing and Regulatory Tribunal (IPART) to ensure prices are based on appropriate cost recovery principles and are transparent.
- Corporatisation of Sydney Water Corporation (SWC), Hunter Water Corporation (HWC).
- Establishment the Sydney Catchment Authority
- Privatisation of all irrigation schemes except Coleambally, which is corporatised.
- Volumetric entitlements on all regulated rivers since 1983 and extensive trade of those entitlements.
- The internal separation of local government water supply and sewerage services from their planning and regulatory functions.
- Establishment State Water within the Department of Land and Water Conservation (DLWC) an internally ring-fence water business responsible for bulk rural water supply services
- Provision of environmental flow shares via the Water Reform initiatives.
- Establishment of the State of the Rivers and Estuaries reporting program.
- Establishment of the Healthy Rivers Commission to undertake independent public inquiries into the health of selected NSW through discussions with interest groups, public hearings and written.
- Introduction of numerous water related education and awareness raising programs
- Establishment of a Water Use Efficiency Advisory Unit to provide education and advice to irrigators.
- Introduction of the Catchment Management Act in 1989 and the creation of catchment management committees throughout the state.
Proposals for a new Water Management Act to replace a number of Acts that presently relate to water management in NSW are currently under discussion. This will appoint the Minister for Land and Water Conservation to the role as the states main water manager. The proposal includes provision for ensuring ecologically sustainable outcomes, security for entitlement holders, clearly defined rules and outcomes, community/government partnerships in water management, tradeability, separation of water entitlements from land ownership and streamlining licensing processes.
The water agenda for NSW over the next few years will be focussed on the goals of the reform agenda, namely:
Water sharing
- legislate to ensure that water is reserved to maintain the fundamental health of aquatic systems and ecological process
- ensure that agreed water quantity and quality environmental objectives can be met through development of environmental flow rules, water management plans and water quality management strategies
- manage water extractions from rivers to meet the agreed environmental objectives and, in inland NSW, the MDBC cap on water diversions
- support the preparation and implementation of estuary management plans
- protect groundwater aquifers at risk from contamination
- promote development of integrated water, sewer and drainage management plans for rural towns and support the implementation of stormwater management plans
- monitor the health of the state's rivers through indicative biological, physical and chemical parameters
- through community consultation find equitable ways to reduce total entitlements back to sustainable yields for all aquifers that are over allocated
- develop an integrated natural resources management data base in partnership with local government and the Commonwealth
- audit and report on the effectiveness of the environmental flow rules in meeting the broad river flow and water quality objectives
- integrate surface and groundwater management
Support to the rural sector
- introduce new water legislation which will clarify water users rights tom access and use water
- convert all water licenses to a volumetric basis and redefine entitlements within the new statutory framework
- complete the initial 5 year period of resource security for regulated rivers, review and prepare management plan for the next period
- commence the initial 5 year period of resource security for unregulated rivers and groundwater systems
- finalise all registrations under the water amnesty and phase out unauthorised extractions
- introduce a water trading system for all water users
- implement the Land and Water Management Plans
- review the focus and direction of the Irrigated Agricultural Water Use Efficiency program to better target government assistance
Water management partnerships and improvements
- Ensure socio-economic impacts of water management rules and strategies are adequately assessed and trade-offs identified
- Ensure that bulk rural water continues to be delivered on a commercial basis within clearly defined parameters
- review the focus and direction of the Country Town Water and Sewerage Supply program to better target assistance
The Australian Natural Resource Atlas contains information about NSW's water resources and in particular it provides information which will help support decision making for ecologically sustainable use of water resources. The information also supports improved water resource efficiency and will help decision-makers assess the influence of environmental, social and economic factors on resource management. Four key areas of interest are summarised at this site and they include:
- Current resource status summarised at the basin and State level including surface water and groundwater availability.
- Current resource use summarised at the basin and State level including surface water and groundwater use, allocation and efficiency of use.
- Water resource development potential summarised at the basin and State level at 2020 and 2050 and including sustainability of surface water and groundwater use, the degree of commitment of the surface water basins and groundwater management units and allocations of surface water for the environment;
- Water resource management options to maintain ecological use of water resources into the future and conform to national water reform compliance.
Surface water reporting units
For this Audit, the 55 surface water management areas, as designated by the DLWC, have been adopted as the reporting unit for NSW. These surface water management areas largely coincide with the old Australian Water Resources Council (AWRC) basins. The only exceptions are the basins within which the Department and the Barwon Darling Management Area operate major storages.
In those basins with major storages the AWRC basin has been further subdivided to distinguish between those parts of the basins in which the DLWC regulates part of the river system to assure supply (regulated basin) and those where it does not (unregulated basin). In a number of the other basins, such as the Hawkesbury-Nepean, Sydney, Shoalhaven and the Snowy, significant regulation is carried out by other agencies but these basins have not been included in the DLWC regulated category. The regulated basins include the Murray-Riverina, Lower Darling, Murrumbidgee, Lachlan, Macquarie, Namoi, Gwydir and Border Rivers within the Murray -Darling basin, and the Bega, Hunter, and Richmond Rivers in coastal NSW.
Groundwater reporting units
Groundwater information has been reported at three levels - Groundwater Management Units (GMUs), Unincorporated Areas (UAs), and Provinces. GMUs are those parts of NSW where groundwater usage is intense, has reached or exceeded the most recent estimate of sustainable yield, where this situation is likely to occur if present trends continue, or where groundwater resources are judged to be at risk for any reason. There are 41 GMUs, ranging from as small as 4 km2 to nearly 40 000 km2. The largest GMUs are those in the eastern part of the Murray Basin, where the initial mid 1980s definition of a GMU included a large area in which saline water was dominant. While this tends to skew data for these larger areas, and there is an argument in favour of reducing their size, in practical terms the problem has been dealt with by subdivision of the GMU into zones. Most of the management effort applied is concentrated in those zones in which low salinity water can be obtained.
UAs in NSW are those areas where the degree of management needed is less. UAs constitute the largest part of the State, ranging in size from about 15800 km2 (Clarence Morton, Oxley Basins) to 238000 km2 (Lachlan Fold Belt Province). These areas comprise those parts of the main sedimentary basins and fractured rock provinces which are not included in the GMUs, namely the Clarence-Morton, Oxley, Gunnedah, Sydney and Murray Basins and the New England, Lachlan and Olary fractured rock provinces.
Two other important areas should be noted. The Border Rivers GMU and the Great Artesian Basin Province both cross State borders. Data for both areas have been compiled by the Queensland Department of Natural Resources, using data obtained from the Great Artesian Basin Consultative Committee and Border Rivers Commission respectively. The Great Artesian Basin has been reported based on 13 groundwater management units, three of which are entirely in NSW.
GMUs and UAs have been grouped and/or defined for the purpose of this Audit into province areas. The concept of groundwater provinces was thought in the 1980s to be a logical basis on which to construct a groundwater management regime, and was used as a comparative unit for the 1985 review of Australia's water resources. In the event, however, this has been found impractical and groundwater management units have been defined on a much more detailed basis. Their boundaries are often influenced by, and in large part coincide with, geological features, but are also in large part purely administrative. The concept of groundwater provinces on a regional scale, as suggested by the earlier work, is therefore not regarded as particularly useful, but has been used here so that some comparisons can be made with the 1985 review.
Additional information on NSW Water Reform initiatives and updates on data as basin specific initiatives are implemented can be obtained from the New South Wales Department of Land and Water Conservation web-site at www.dlwc.nsw.gov.au
How much surface water does New South Wales have?
By world standards Australia receives little rainfall on average, and loses much of this to evaporation. Australia not only has a low average rainfall compared with other continents, but its runoff averages only 12% of rainfall compared with around 40% for Europe and North America. For NSW the runoff averages 17% for the coastal basins (varying between 12% and 30%) and 3.5% for the inland basins (varying between 0.01% and 31%).
About 75% of the runoff occurs on the coast where 90% of the population is concentrated; yet the coast uses only about 20% of the total water used in the State. Eighty percent cent of water use occurs west of the Great Dividing Range, where only 25% of the surface runoff occurs.
The mean annual streamflow of the State under natural conditions is 42,000 GL, which is equivalent to approximately 10% of all flows in Australian streams.
NSW is located between the summer monsoon rainfall system of northern Australia and the winter cold front rainfall system of southern Australia. River flows in NSW show distinct variations in time, with streamflow showing both a seasonal pattern and substantial year to year variability in discharge.
The inland Murray and Murrumbidgee Rivers in the south of NSW experience most of their runoff in the late winter/spring period, with about 58% of the average annual natural flow in the Murrumbidgee River occurring in the four month period from July to October. The seasonal pattern in the northern inland rivers is less obvious with 36% of the average annual natural flow in the Gwydir River occurring in the four month period from July to October, and 31% in the three month period from January to March. The annual flow in the southern inland rivers is less variable than in the north rivers with the minimum and maximum annual natural flows for the Murrumbidgee being 12% and 392% of the average annual natural flow, while for the Gwydir River the range is 5% to 480%. The Macquarie River located in the central inland part of NSW demonstrates the most variability of the western flowing rivers with minimum and maximum annual natural flow ratios of 3% and 780%.
The inland rivers with the lowest average annual flows are those flowing from Queensland and crossing the border west of Mungindi. Therefore it is not unexpected that the Darling River is subject to extreme variability with minimum and maximum annual natural flow ratios of 7% and 300%.
For coastal streams the catchment size and distance from the coast are the main factors influencing the flows. The large coastal catchments of the Clarence, Hunter and Hawkesbury -Nepean Rivers have proportionally low rates of flow. The exception is the Snowy River which benefits from snow melt, although a large part of its flow is now diverted inland.
Available resource
The total average annual surface water resource for NSW is 42,000 GL. This information has been determined from a combination of water resource system models and historical flow analysis.
The total annual divertible surface water resource for NSW cannot be provided at this stage as yield information cannot be determined for the unregulated rivers in the State. This is due to the lack of
- reliable water use data;
- water sharing rules that effectively represent NSW approach to environmental flow requirements; and
- water resource system models to assist planning decisions.
NSW has therefore taken the approach that it is better to await the availability of data based on reliable and realistic analysis than to divert limited resources from the water reform process at this time.
NSW has, consequently, placed a high priority on the management of the unregulated rivers. Management plans for the most highly stressed unregulated rivers will be prepared by 2001. Plans for other stressed and high conservation unregulated rivers will be completed by 2003, and all major unregulated rivers completed by 2005.
As studies are completed yield information for unregulated streams will be available on the DLWC web site at www.dlwc.nsw.gov.au
With respect to the regulated streams, most of these occur inland and are part of the Murray-Darling Basin. As this basin is subject to a cap on diversions, NSW has assumed that there will be no further infrastructure development in the basin that would increase diversions. In fact in the valleys where NSW has implemented environmental flow rules average annual diversions are expected to decrease below the MDBC cap values.
In these basins the divertible yield has been determined on the basis of simulation models which assume the 1993/94 levels of infrastructure development, cap management rules and, with the exception of the Macquarie basin, make no major provision for environmental flows. On the basis of no further development under the MDBC cap, the developed yield has been taken to be equal to the divertible yield for these basins. Finally, the sustainable yield has been taken as the average annual use with current infrastructure development and MDBC cap plus environmental flow rules.
For the regulated NSW portion of the Murray-Darling basin, both the total divertible and the developed yield is 68% of the total resource for that portion of the basin; while the sustainable yield is 42% of the total resource. This excludes those management areas where a sustainable yield is yet to be determined (the Murray, Barwon-Darling and NSW Border Rivers). Each of these three areas are considered to be over developed.
Of the coastal basins in which parts of the river systems are regulated by the DLWC, only the Hunter has been modelled and has yield values available; the remaining basins (Richmond and Bega), and those in which stream controls are exercised by other bodies, have not had yield values determined.
As a result of having more reliable streamflows in the southern valleys in the NSW portion of the Murray-Darling basin, the NSW management area with the most highly developed surface water resource is the Murrumbidgee basin, which has a developed yield of 2,186 GL. This represents 25% of the total resources and 36% of the divertible yield of the NSW portion of the Murray-Darling basin.
How saline are New South Wales' surface water resources?
| Surface Water Managemnet Area | <500 mg/l (GL/yr) | 500 - 1500 mg/l (GL/yr) | 1500 - 5000 mg/l (GL/yr) | 5000 -14000 mg/l (GL/yr) | >14000 mg/l (GL/yr) | Total volume (GL/yr) |
|---|---|---|---|---|---|---|
| New South Wales | 9,641 | 64 | 2,317 | no data | no data | no data |
| Barwon Darling Management Area | 70 | 12 | 146 | no data | no data | 192 |
| Bega River - Regulated | no data | no data | no data | no data | no data | no data |
| Bega River - Unregulated | no data | no data | no data | no data | no data | no data |
| Bellinger River | no data | no data | no data | no data | no data | no data |
| Benanee | no data | no data | no data | no data | no data | 0 |
| Border Rivers (NSW Part Only) | no data | no data | no data | no data | no data | no data |
| Border Rivers (NSW) - Regulated | 314 | no data | 40 | no data | no data | 196 |
| Brunswick River | no data | no data | no data | no data | no data | no data |
| Bulloo River (NSW Part Only) | no data | no data | no data | no data | no data | 0 |
| Castlereagh River | no data | no data | no data | no data | no data | no data |
| Clarence River | no data | no data | no data | no data | no data | no data |
| Clyde River - Jervis Bay | no data | no data | no data | no data | no data | no data |
| Condamine - Culgoa Rivers (NSW Part Only) | 0 | 0 | 0 | no data | no data | 0 |
| Coopers Creek (NSW Part Only) | no data | no data | no data | no data | no data | 0 |
| Darling River - Regulated | 100 | 2 | 96 | no data | no data | 147 |
| Darling River - Unregulated | no data | no data | no data | no data | no data | no data |
| East Gippsland (NSW Part Only) | no data | no data | no data | no data | no data | no data |
| Gwydir River - Regulated | 379 | no data | 214 | no data | no data | 403 |
| Gwydir River - Unregulated | no data | no data | no data | no data | no data | no data |
| Hastings River | no data | no data | no data | no data | no data | no data |
| Hawkesbury River | no data | no data | no data | no data | no data | no data |
| Hunter River - Regulated | no data | no data | no data | no data | no data | no data |
| Hunter River - Unregulated | no data | no data | no data | no data | no data | no data |
| Karuah River | no data | no data | no data | no data | no data | no data |
| Lachlan River - Regulated | 244 | no data | 149 | no data | no data | 271 |
| Lachlan River - Unregulated | no data | no data | no data | no data | no data | no data |
| Lake Bancannia | no data | no data | no data | no data | no data | 0 |
| Lake Frome (NSW Part Only) | no data | no data | no data | no data | no data | 0 |
| Lake George | no data | no data | no data | no data | no data | no data |
| Lower Murray River (NSW Part Only) | no data | no data | no data | no data | no data | 0 |
| Macleay River | no data | no data | no data | no data | no data | no data |
| Macquarie - Tuggerah Lakes | no data | no data | no data | no data | no data | no data |
| Macquarie River - Regulated | 335 | 5 | 293 | no data | no data | 465 |
| Macquarie River - Unregulated | no data | no data | no data | no data | no data | no data |
| Manning River | no data | no data | no data | no data | no data | no data |
| Moonie River (NSW Part Only) | no data | no data | no data | no data | no data | 0 |
| Moruya River | no data | no data | no data | no data | no data | no data |
| Murray (Hume to Border) - Regulated (NSW Part Only) | 3,828 | no data | no data | no data | no data | 1,914 |
| Murrumbidgee River - Regulated | 4,242 | no data | 66 | no data | no data | 2,187 |
| Murrumbidgee River - Unregulated | no data | no data | no data | no data | no data | no data |
| Namoi River - Regulated | 135 | 15 | 158 | no data | no data | 240 |
| Namoi River - Unregulated | no data | no data | no data | no data | no data | no data |
| Paroo River (NSW Part Only) | no data | no data | no data | no data | no data | 0 |
| Richmond River - Regulated | no data | no data | no data | no data | no data | no data |
| Richmond River - Unregulated | no data | no data | no data | no data | no data | no data |
| Shoalhaven River | no data | no data | no data | no data | no data | no data |
| Snowy River (NSW Part Only) | no data | no data | no data | no data | no data | no data |
| Sydney Coast - Georges River | no data | no data | no data | no data | no data | no data |
| Towamba River | no data | no data | no data | no data | no data | no data |
| Tuross River | no data | no data | no data | no data | no data | no data |
| Tweed River | no data | no data | no data | no data | no data | no data |
| Upper Murray River (NSW Part Only) | no data | no data | no data | no data | no data | no data |
| Warrego River (NSW Part Only) | 0 | no data | no data | no data | no data | 0 |
| Wollongong Coast | no data | no data | no data | no data | no data | no data |
How much surface water has been developed?
There are eight major regulated river systems servicing predominantly irrigation development. In these systems, the river channel itself is the major water supply system from the one or more headwater storages. These systems occur in the Murray, Murrumbidgee, Lachlan, Macquarie, Namoi, Gwydir and Border River catchments in the Murray-Darling basin, and the Hunter River catchment on the coast. The major urban water supply schemes operated by Sydney Water Corporation services the greater Sydney region, the Hunter Corporation services Newcastle and the Gosford-Wyong Joint Water Supply Authority services the central coast. They are integrated systems that comprise of a number of dams and transfer works that divert water across basin boundaries. A number of other smaller rural urban water supply schemes exist on the coast and the inland. Most of these do not involve diversion of water across basin boundaries.
There are 90 storages (each with a volume capacity exceeding 1000 ML) located across the State. These represent a total storage capacity of 32,065 GL.
How committed are New South Wales' surface water resources?
The NSW Water reform initiatives adopted a catchment classification system based on assessed level of environmental degradation (environmental stress) and proportion of flow extracted (hydrologic stress). This approach results in a matrix of 9 classifications of stress, which are grouped in 3 categories. http://www.dlwc.nsw.gov.au/care/water/wr.pdfs/wr_fs14.pdf
For the purposes of the assessment the NSW Stressed Streams classification was related to the national 4-class development status categories. The Category 4, over-developed management areas comprise an area of some 409,000 sq. km.
| Basin/SWMA | Volume diverted (GL/yr) | Sustainable (GL/yr) | Diversion Development class |
|---|---|---|---|
| Barwon Darling Management Area | 192 | no data | OVER DEVELOPMENT |
| Bega River - Regulated | 5 | no data | OVER DEVELOPMENT |
| Bega River - Unregulated | no data | no data | MEDIUM DEVELOPMENT |
| Bellinger River | no data | no data | MEDIUM DEVELOPMENT |
| Benanee | no data | no data | OVER DEVELOPMENT |
| Border Rivers (NSW Part Only) | no data | no data | OVER DEVELOPMENT |
| Border Rivers (NSW) - Regulated | 196 | no data | OVER DEVELOPMENT |
| Brunswick River | no data | no data | MEDIUM DEVELOPMENT |
| Bulloo River (NSW Part Only) | 0 | 0 | LOW DEVELOPMENT |
| Castlereagh River | no data | no data | OVER DEVELOPMENT |
| Clarence River | no data | no data | LOW DEVELOPMENT |
| Clyde River - Jervis Bay | no data | no data | LOW DEVELOPMENT |
| Condamine - Culgoa Rivers (NSW Part Only) | no data | no data | OVER DEVELOPMENT |
| Coopers Creek (NSW Part Only) | 0 | 0 | LOW DEVELOPMENT |
| Darling River - Regulated | 147 | no data | OVER DEVELOPMENT |
| Darling River - Unregulated | no data | no data | OVER DEVELOPMENT |
| East Gippsland (NSW Part Only) | no data | no data | LOW DEVELOPMENT |
| Gwydir River - Regulated | 360 | 360 | OVER DEVELOPMENT |
| Gwydir River - Unregulated | no data | no data | OVER DEVELOPMENT |
| Hastings River | no data | no data | MEDIUM DEVELOPMENT |
| Hawkesbury River | no data | no data | MEDIUM DEVELOPMENT |
| Hunter River - Regulated | 114 | 114 | OVER DEVELOPMENT |
| Hunter River - Unregulated | no data | no data | HIGH DEVELOPMENT |
| Karuah River | no data | no data | LOW DEVELOPMENT |
| Lachlan River - Regulated | 259 | 259 | OVER DEVELOPMENT |
| Lachlan River - Unregulated | no data | no data | OVER DEVELOPMENT |
| Lake Bancannia | no data | no data | LOW DEVELOPMENT |
| Lake Frome (NSW Part Only) | 0 | 0 | LOW DEVELOPMENT |
| Lake George | no data | no data | OVER DEVELOPMENT |
| Lower Murray River (NSW Part Only) | no data | no data | OVER DEVELOPMENT |
| Macleay River | no data | no data | MEDIUM DEVELOPMENT |
| Macquarie - Tuggerah Lakes | no data | no data | MEDIUM DEVELOPMENT |
| Macquarie River - Regulated | 407 | 407 | OVER DEVELOPMENT |
| Macquarie River - Unregulated | no data | no data | OVER DEVELOPMENT |
| Manning River | no data | no data | LOW DEVELOPMENT |
| Moonie River (NSW Part Only) | no data | no data | OVER DEVELOPMENT |
| Moruya River | no data | no data | LOW DEVELOPMENT |
| Murray (Hume to Border) - Regulated (NSW Part Only) | 1,914 | no data | OVER DEVELOPMENT |
| Murrumbidgee River - Regulated | 2,145 | 2,145 | OVER DEVELOPMENT |
| Murrumbidgee River - Unregulated | no data | no data | OVER DEVELOPMENT |
| Namoi River - Regulated | 227 | 227 | OVER DEVELOPMENT |
| Namoi River - Unregulated | no data | no data | OVER DEVELOPMENT |
| Paroo River (NSW Part Only) | no data | no data | OVER DEVELOPMENT |
| Richmond River - Regulated | 1 | no data | LOW DEVELOPMENT |
| Richmond River - Unregulated | no data | no data | LOW DEVELOPMENT |
| Shoalhaven River | no data | no data | MEDIUM DEVELOPMENT |
| Snowy River (NSW Part Only) | no data | no data | MEDIUM DEVELOPMENT |
| Sydney Coast - Georges River | no data | no data | OVER DEVELOPMENT |
| Towamba River | no data | no data | LOW DEVELOPMENT |
| Tuross River | no data | no data | LOW DEVELOPMENT |
| Tweed River | no data | no data | MEDIUM DEVELOPMENT |
| Upper Murray River (NSW Part Only) | no data | no data | OVER DEVELOPMENT |
| Warrego River (NSW Part Only) | no data | no data | OVER DEVELOPMENT |
| Wollongong Coast | no data | no data | LOW DEVELOPMENT |
The volume diverted is the total volume of the SWMA's surface water resources diverted for use both within the management area and for export to other management areas.
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 in relation to sustainable water management.
It is important to recognise that adequately quantifying a sustainable flow regime or sustainable yield and consequent operating rules is a complex matter. State, Territory and scientific agencies continue to develop and apply methods and measures for determining sustainable flow regimes and sustainable yields.
This categorisation provides a general guide only. Please refer to the State and Territory Overview and Technical reports for detail on the analysis methods used.
| Category | Development status | ||
|---|---|---|---|
| 1 | <30% | Low development | |
| 2 | 30 - 70% | Moderate development | |
| 3 | 70 - 100% | Highly developed | |
| 4 | 100% | Overdeveloped | |
| * Water use as a percentage of sustainable flow regime (surface water) and sustainable yield (groundwater) | |||
How much groundwater does New South Wales have?
Hydrology and available resource
The dominating influences on the location and magnitude of groundwater resources in New South Wales are geology, geomorphology and climate. The run-off divide formed by the Great Dividing Range separates the short steep eastwards flowing rivers which flow directly into the Pacific Ocean from the western flowing rivers which have a much longer and more circuitous course to the Southern Ocean as tributaries of the Murray River.
The eastern flowing rivers have, on the whole, had a relatively short period since the last major sea level changes in which to develop, and there has been only a limited development of alluvial deposits. Where such deposits do occur, they commonly grade laterally into unconsolidated estuarine and marine deposits. Consequently the highly productive aquifer systems often associated with alluvial deposits are generally not available in association with these eastern flowing rivers. Extensive, but shallow, alluvial deposits are associated with the Hunter and Richmond Rivers, and in the former case are important sources of groundwater mainly used for irrigation. The other coastal river systems have only limited groundwater resources associated with their alluvial deposits but are used extensively as a stock and domestic source of water especially during droughts.
The most productive aquifer systems in the eastern coastal region are the coastal dune deposits, which have been extensively developed along some parts of the coast during a succession of sea level changes. Of particular importance are the Tomago Sand Beds and associated Tomaree and Stockton deposits, which provide an important part of the water supply for Newcastle and surrounding areas.
The western flowing rivers have a much longer route to the sea, with lower gradients across the western slopes and plains. Alluvial deposits have formed extensively along their valley systems, and in the case of the southern rivers, in delta areas where in past times they debouched into the eastern marginal areas of the lakes and swamps of the Murray Basin. A large proportion of these deposits formed during periods when the climate was very humid, resulting in chemical deposition of the products of erosion from the highlands. Under these conditions, quartz grains remain as an inert residual product while all other products of decomposition are soluble and removed as part of the salt load of the rivers. The outcome of this process is the accumulation of thick and extensive deposits of clean quartz gravel and sand, and it is these deposits which form the main aquifers in the westerly flowing river systems in New South Wales.
The most substantial deposits within the river valleys are in the Murrumbidgee Valley (upstream of Narrandera), the Namoi Valley, and the Lachlan Valley (upstream from Hillston), and in all these areas it is possible to construct bores with very large supplies. Pumping rates of 20 ML/day are not uncommon, and the salinity of the water is as low as 300 mg/L. Less substantial resources are available in all the other westward flowing rivers, to a varying degree. In the case of the Murrumbidgee, Murray and Lachlan Rivers, extensive deposits of coarse quartz sand and gravel have accumulated in deltas formed where the rivers left the main valley system and entered the low lying Murray Basin area. These are best developed in the Darlington Point and Hillston areas on the Murrumbidgee and Lachlan Rivers respectively, and many bores are capable of yields of 30 ML/d or more.
The alluvial deposits described above are, in terms of their geological character, superficial. That is, they form a thin veneer on some parts of the landscape, obscuring the basement rocks beneath them. Those underlying rocks are of varying character and have a very wide range of water storage and transmitting capacity. Sandstone, with residual intergranular porosity, is in general the most highly productive of them and in New South Wales they occur in a number of large sedimentary basins. By far the most important from a groundwater sense is the Great Artesian Basin. It occupies an area which covers 20% of the Australian landmass extending over four States/Territories, and its water resources are discussed elsewhere.
The Oxley Basin contains a sandstone formation, which is an extension of the main sandstone aquifer of the GAB, and although artesian conditions in it are such that bores do not flow to the surface it is possible to pump moderately large supplies of water from bores. The aquifer is extensively covered and obscured by the basalt of the Liverpool Range. Sandstone in the Clarence-Morton, Gunnedah and Sydney Basins are generally less productive than in the GAB or Oxley Basins. Stock and domestic supplies are commonly available, but bores with yields sufficient for irrigation, municipal or industrial use are rare. There are several areas within the Sydney Basin, where circumstances such as locally better permeability and/or recharge conditions in the Hawkesbury Sandstone aquifer have resulted in slightly higher pumping rates being available. Concentrated usage in some of these has led to a degree of competition locally for access to supplies.
Older fractured crystalline rocks of igneous or metamorphic origin form the landscape in large areas of the State, and have been grouped here into the New England, Lachlan Fold Belt and Olary Provinces. These rocks are intrinsically impermeable, and only attain a degree of porosity and permeability, which enables them to store and transmit water by secondary processes. Such processes may be tectonism (earth movements) which causes fracturing and jointing and consequently open spaces within the rock mass, or chemical erosion which may differentially remove some of the rock mass leaving a matrix of residual material with some porosity and permeability. In the more humid areas along the Great Dividing Range, small pumping rates sufficient for stock and domestic use and with salinity generally less than about 1500-2000 mg/L. Towards the west, as the rainfall decreases and the land slopes and elevation which control the hydraulic gradients decrease, the salinity increases gradually and is generally such that the water can only be used for stock watering and limited domestic purposes.
Sustainable yield and environmental allocation
Environmental requirements have been addressed, from a groundwater perspective, by reserving a default allowance of 30% of estimated long-term average annual recharge. That is, under standard arrangements, the sustainable yield of an aquifer system is taken to be 70% of the recharge. This is in lieu of real information about the actual needs of groundwater dependent ecosystems, and will be used until such time as better information becomes available. Variation from the 70% allowance will be made in certain circumstances but to date has only really occurred in the Namoi valley where for social reasons and in the apparent absence of significant groundwater dependent ecosystems the sustainable yield has been taken as 100% of recharge.
The broad approach described above will operate at a Groundwater Management Unit and sub-unit (zone) level. Other measures to protect the environment, such as buffer zones or maintaining water levels within a band width , are used at the paddock scale to provide protection to the environment.
The following paragraphs have been adapted from the DLWC report Sustainable Yield Estimates for High Risk Aquifers In NSW (J Ross, 1999, In Press). They outline NSW current approach to estimation of sustainable yield.
One of the most basic pieces of data required for sensible management of a resource is the quantity of input to a system or recharge. In the past, the quantity of recharge to an aquifer was accepted as an amount equivalent to the safe yield or quantity of water that could be removed from an aquifer artificially on a sustainable basis. We now understand that the sustainable yield of an aquifer is usually a quantity that is considerably less than recharge so adequate provision for the environment can be made. Nevertheless, a sustainable yield figure is derived from a recharge determination. With this in mind, any sustainable yield study will always involve the determination of recharge as a first necessary step.
The following working definition has been adopted:
Sustainable yield is that proportion of the long term average annual recharge which can be extracted each year without causing unacceptable impacts on the environment or other groundwater users
From the above definition, it is immediately apparent that the actual proportion is not specifically given. This proportion will change according to each situation and is assigned differently to each aquifer system. Recharge calculations with sustainability factors applied to them act as interim sustainable yield figures. These sustainability factors are some proportion of long term annual average recharge. While adhering to the precautionary principle, sustainability factors are chosen according to level of knowledge of an aquifer system, level of use of that resource, the magnitude of perceived risk to that aquifer system and the environment, and the reliability of recharge to that system. As better understanding is developed, the sustainable yields can be adjusted accordingly. The initial figures are intended to be conservative while bearing in mind that it is most often easier to subsequently adjust Sustainable Yield values upward rather than downward. Sustainability factors offer protection to the integrity of the groundwater system itself and ultimately all groundwater users including the environment and ensure that neither temporary nor permanent damage to the aquifer system results from overuse.
Sustainable yield values can - and indeed will - change over time as our technical understanding of the dynamics of individual groundwater systems is enhanced as a result of more rigorous investigation and in response to changes in natural and socio-economic realities. In short, this is a commencement of a continuous process of periodic review and adjustment of sustainable yield estimates. It follows therefore that a set of sustainable yield figures will reflect a level of understanding that exists at a point in time. Groundwater management committees may change the sustainable yield factor to suit local conditions.
High levels of accuracy in determining sustainable yield require a degree of rigorous study that would take years if not decades to achieve. As many systems are either over-allocated or about to become over-allocated, it is not practical nor is it in the best interests to wait those decades before adopting allocation ceilings that are technically highly accurate. In short, at this stage a very high degree of accuracy is not required to commence management consistent with the philosophy of sustainability. Nevertheless, the approach applied has generated a set of figures that have been produced as a synthesis of knowledge accumulated to the present and have been adjusted according to good hydrogeological common sense and an understanding of local issues. Additionally, the approach has been conservative in the interest of resource protection but tempered with compromise recognising the need to preserve current development and acknowledging the importance of encouraging continued development where appropriate to do so.
Where rigorous numerical models have been developed and have resulted in the generation of acceptable recharge figures for an aquifer system, these values have been adopted as acceptable for use in sustainable yield determinations. In some cases systems that are similar to a modelled system have had recharge determined empirically using the modelled system as a reference.
The first question asked was therefore Does a model exist? If so, has it produced acceptable recharge figures? If this was the case, those recharge figures were used. If not, alternate assessment was carried out.
Most systems however, have not been modelled. In those cases, inputs (or recharge) to the system have generally been kept to rainfall and river components of recharge. (Three systems, The Lower Lachlan, The Lower Murrumbidgee, and the Great Artesian Basin have been handled differently with regard to Sustainable Yield determinations and are given separate explanation below). Throughflow and underflow have in most cases been omitted from calculations in the interest of both simplicity and conservatism. Likewise, irrigation returns have not been considered even though in some situations, a certain proportion of irrigated water might be expected to access the underlying aquifer.
Two equations were used to estimate recharge. Both have a limited number of terms and allow recharge values to be assigned respectively to:
- Rainfall sourced and;
- River sourced.
Rainfall recharge was calculated simply according to assessed rainfall, area and proportion of rainfall accessing the aquifer. River recharge was estimated using an equation, which is a modified form of the Darcy equation that is used in the assessment of river recharge in the Modflow software package that models groundwater flow. The result is a theoretical contribution of the river to the recharge. An additional factor was applied to this result as an adjustment factor intended to reduce the theoretical river recharge and is set as a) the fraction of the year and/or b). fraction of river reach - that is considered as a loosing stream. In this way an actual river recharge component is produced.
There is a strong subjective character to the results achieved by the above method. This subjective character is unavoidable because of the general approach to the problem at hand. Additionally, in most cases our understanding of the groundwater systems in the State is general itself and requires that a variety of assumptions be made based on similarities to known conditions. These assumptions however are made with common sense and with hydrogeological principles in mind and are therefore valid within the needs of the present situation.
Once recharge values have been estimated, some proportion of that recharge is taken as the Sustainable Yield. The setting of this proportion again introduces an element of subjectivity. As a default however, 70% of average annual rainfall is taken as the proportion that can be extracted form the aquifer annually on a sustainable basis. This is consistent with the situation in Victoria where 70% is the default figure. Therefore unless designated otherwise for specific reasons 70% of annual average recharge is taken as the sustainable yield of the aquifer. Similar to the terms in the recharge equations, the sustainable yield factor is somewhat arbitrary but does offer what is considered to be adequate protection and security to the groundwater system, environment and extractive users.
How committed are New South Wales' groundwater resources?
| Province | Over | High | Med | Low | Total (GL/yr) | ||
|---|---|---|---|---|---|---|---|
| Clarence-Morton | GMU | 25 | 27 | 20 | 8 | 78 | |
| UA | no data | no data | no data | 9 | 9 | ||
| Great Artesian | GMU | 919 | 2 | 9 | 1 | 1,017 | |
| UA | no data | no data | no data | no data | no data | ||
| Lachlan | GMU | 256 | 198 | 58 | 27 | 538 | |
| UA | no data | no data | no data | 71 | 71 | ||
| Murray | GMU | 1,125 | 417 | 50 | 15 | 1,607 | |
| UA | no data | no data | no data | 27 | 27 | ||
| New England | GMU | 79 | no data | 16 | 6 | 100 | |
| UA | no data | no data | no data | 46 | 46 | ||
| Olary | GMU | no data | no data | no data | no data | no data | |
| UA | no data | no data | no data | 1 | 1 | ||
| Sydney | GMU | 446 | 8 | 3 | 30 | 485 | |
| UA | no data | no data | no data | 26 | 26 | ||
| Note: "GMU"=Groundwater Management Unit "UA"=Unallocated Area | |||||||
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 in relation to sustainable water management.
It is important to recognise that adequately quantifying a sustainable flow regime or sustainable yield and consequent operating rules is a complex matter. State, Territory and scientific agencies continue to develop and apply methods and measures for determining sustainable flow regimes and sustainable yields.
This categorisation provides a general guide only. Please refer to the State and Territory Overview and Technical reports for detail on the analysis methods used.
| Category | Development status | ||
|---|---|---|---|
| 1 | <30% | Low development | |
| 2 | 30 - 70% | Moderate development | |
| 3 | 70 - 100% | Highly developed | |
| 4 | 100% | Overdeveloped | |
| * Water use as a percentage of sustainable flow regime (surface water) and sustainable yield (groundwater) | |||
How saline are New South Wales' groundwater resources?
| Province | <1500 mg/l (GL/yr) | 5000 mg/l (GL/yr) | 14000 mg/l (GL/yr) | >14000 mg/l (GL/yr) | Total volume (GL/yr) | |
|---|---|---|---|---|---|---|
| New South Wales | GMU | 553580 | 1274550 | 167770 | 543300 | |
| UA | 3026044 | 789900 | 1095000 | |||
| Clarence-Morton | GMU | 134,200 | 120 | 29 | 16 | 2 |
| UA | no data | 507 | no data | no data | no data | |
| Great Artesian | GMU | 187,400 | 327 | 90 | 41 | 30 |
| UA | no data | no data | no data | no data | no data | |
| Lachlan | GMU | 342,635 | 268 | 6 | 7 | no data |
| UA | no data | no data | no data | 429 | no data | |
| Murray | GMU | 157,010 | 458 | 251 | 128 | 30 |
| UA | no data | no data | no data | no data | 500 | |
| New England | GMU | 88,080 | 27 | no data | no data | no data |
| UA | no data | 1,865 | no data | no data | no data | |
| Olary | GMU | no data | no data | no data | no data | no data |
| UA | no data | no data | no data | 153 | no data | |
| Sydney | GMU | 133,300 | 410 | no data | no data | no data |
| UA | no data | 734 | no data | 208 | no data |
How much water does New South Wales trade?
The Total reported Volume Traded in New South Wales is 305 GL; in 1135 transactions.
The State and Territory water management agencies continue to consider water use efficiency and optimisation strategies within existing infrastructure (e.g. water supply efficiency, precision irrigation and scheduling, water recycling, trading and pricing) as part of water resource development planning.
Recognising that water is a finite resource, the States and Territories have developed water allocation systems where security and reliability are assigned to entitlement, trading is provided so water can be moved to high value uses and the choices of individuals are maximised.
Part of the decision-making framework to enable and facilitate water trading, changes in water allocation and definition of rights to water is the need for water use monitoring. Water use monitoring will assist decision-making and provide an opportunity over time to evaluate the effectiveness of allocation policies.
Environmental water requirements
Except for the East Coast and the uplands on the west of the divide, NSW rivers are generally small in channel capacity, flat graded, extremely sinuous with broad flood plains. Natural flows are extremely variable compared with rivers in most of the world. Generally the main channel of inland rivers carries only 10% to 50% of the flow in high floods. The rivers do not have a regular seasonal flow pattern to the same extent as the rest of the world. However, the southern inland rivers of NSW have a more regular seasonal pattern (wet winter/spring and dry summer/autumn) than the central and northern inland rivers. It is not uncommon for the lower parts of inland rivers to cease to flow for a few months during extreme droughts and have low flows for a few years during extended droughts. The periods between over-bank floods can be as long as 3 to 5 years for the southern inland rivers and up to 10 years for the northern inland rivers. On the other hand floods can occur a number of times during a year and a number of years in succession.
Australia's and NSW river based ecology has adapted to this variability, attuning itself to the extreme uncertainty and variability in stream flows and river levels. The recruitment of species generally takes place in periods of maximum food availability during over-bank flood flows of adequate duration. In extreme droughts the population probably declines to the most robust that survive in natural protected habitats. For most of the time species population is maintained by events that produce food from flood plains, billabongs and in-river benches.
Therefore the NSW Water Reform and its approach to sustainable management of surface water resources has focused on developing and implementing a series of management strategies that seek to restore some of the full range of the natural flow pattern to NSW rivers. The full range of the natural flow pattern has been altered by development within the whole catchment including, major dams, irrigation and other diversions, flood plain flow water harvesting, flood protection schemes, upland farm dams and the operational procedures used by water supply and distribution authorities and users.
A number of hydrologic measures other than average or median flows alone have been adopted as performance indicators for the development and implementation of Water Reform management actions. Action is being taken to base these measures on daily flow analysis. The measures include flow duration curves, flow sequences, ecologically significant event analysis (frequency and duration of events, duration between events).
Environmental requirements have been addressed, from a groundwater perspective, by reserving a default allowance of 30% of estimated long term average annual recharge. That is, under standard arrangements, the sustainable yield of an aquifer system is taken to be 70% of the recharge. This is in lieu of real information about the actual needs of groundwater dependent ecosystems, and will be used until such time as better information becomes available. Variation from the 70% allowance will be made in certain circumstances but to date has only really occurred in the Namoi valley where for social reasons and in the apparent absence of significant groundwater dependent ecosystems the sustainable yield has been taken as 100% of recharge.
The broad approach described above will operate at a Groundwater Management Unit and sub-unit (zone) level. Other measures to protect the environment, such as buffer zones or maintaining water levels within a bandwidth are used at the paddock scale to provide protection to the environment.
Further information
Reports
- NSW Water Resources Assessment 2000 Report
- NSW Water Resources Assessment 2000 Technical Report
- Study of Streamflow data and modelled streamflow report
Data
- Extension of unimpaired monthly streamflow data and regionalisation of parameter values to estimate streamflow in ungauged catchments (NLWRA 2000)
- Surface Water Management Areas
- Groundwater management units and provinces - ARC/INFO export
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