Australian Natural Resources Atlas

Natural Resource Topics

Water resources - Allocation and Use - Australian Capital Territory

Location Map

Australian Capital Territory

How has Australian Capital Territory's water use changed since 1985?

Comparison between the 1985 and 2000 'snapshot' assessments is difficult. Factors include the time between assessments (more than 15 years); seasonality and variability of climate; significant potential for changes in land use; and fluctuations in domestic and global market demands.

Water Use, Climate and the Audit Baseline Year - 1996/97

The baseline year for the Audit is the 1996/97 agricultural year starting on the 1st April and ending on 31st of March. For water use the data was compiled for the period 1 July 1996 to 30 June 1997 (water calendar year). When it is necessary to collect information for more than one year, the data collected must cover that year or, alternatively, appropriately adjusted to provide a best estimate for that year.

For water use data States and Territories were requested to provide a 5 yearly average value based on the 1996/97 year. Use figures were adjusted in areas where, due to climatic conditions, the water use was not considered to be 'average'.

Climate in 1996/97

During 1996 there was a transition from the weak large-scale climate controls to a strong El Ni?o condition after March 1997. This resulted in a drying over a large part of southern and eastern Australia. From July until September 1996 Victoria had unusually cold and wet weather. The remainder of the southern half of Australia was also wet for three months. Significant areas in south-west Queensland, western and central New South Wales, South Australia, western Victoria, and southern Western Australia had rainfall totals within the highest 10% on record.

During the summer of 1996-97, there was a very active monsoonal season in the tropical zones in western Australia and the Northern Territory. However, this finished abruptly and early, as El Ni?o developed rapidly in autumn 1997. From October 1996 very dry conditions prevailed over most of Victoria, the grain belts of South Australia and north-east Tasmania. Areas of southern Victoria through to south-east South Australia had the driest October to June period on record.

May 1997 brought rain to southern Australia and average to above average rain to parts of Queensland. There was some relief to farmers from the dry and hot conditions over southern Australia in early 1997. In parts of southern Victoria and south-east South Australia the driest October to June period was reported. (ABS Water Account, 2000)

Climate in 1983/84 (Water Review 85)

Water use in any particular year is affected by weather conditions. For much of Australia, the period, July 1983 to June 1984, was equivalent to a normal year in which water use was about average. In south-east Australia, however, abnormal weather patterns were experienced. In general, rainfall totals throughout Victoria were high during the first half of the year but were lower than average in the second half. These weather conditions, along with a continuing sensitivity to water use following the 1982/83 drought, had a marked effect on water usage. Although the 1982/83 drought that affected most of Victoria was broken by above-average rains early in the year, water restrictions in many urban areas were not lifted until much later in the year. Urban water use was therefore less than average, due both to the heavy rains and to the continuance of water restrictions.

The above-average rains in the first half of 1983-84 greatly reduced irrigation demands, and by mid-season virtually unrestricted supplies of water were made available to farmers (for example, 200% of water rights in the Goulburn-Murray Irrigation District). The drier conditions in the latter half of the year somewhat compensated for this, but total usage for the year was generally far less than average.

Rural usage was also less than average, again due to the early wet conditions and sensitivity about excessive water use following the 1982-83 drought. (DPIE, 1987).

Map of change in total water since 1985

Note: The change in water use volume from 1985 to 1996 does not always reflect factors affecting consumption patterns and volumes such as population growth, industry or land-use change or operational improvements. The observed difference may partly be attributed to differences in the approach and assumptions used to estimate water use within the river basin.

Chart of Proportion of total water use by consumptive classes
Basin NameUse in 1983-84 (GL /yr)Use in 1996-97 (GL /yr)% Change
ACTno data68 no data

Note: The total surface water use reported for each river basin does not include the water consumption of the eleven major cities. The data for cities and river basins are reported in the State totals.

How are the surface water resources used and allocated in Australian Capital Territory?

Chart of Proportion of surface water use by consumptive classes

Table: Surface water diversion and allocation 1996-97

Basin/SWMA Name Allocation (GL/yr) Diversion (GL/yr) Diversion: Allocation (%)
Australian Capital Territory 71 68 0
Murrumbidgee River A  51 51 100
Murrumbidgee River B  2 2 55
Murrumbidgee River C  18 16 89

Note: Allocation is not based on 1999-2000 estimates; Diversion based on five-yearly average 1996-97.

Note: In the table above, the total surface water use reported for each river basin does not include the water consumption of the eleven major cities. The data for cities are reported in the State totals. 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 area.

The total volume of surface water licensed for use in the ACT Management Area is around 66 GL per year. This amount of water includes the ACTEW allocation for urban water supply and private diversion licences (groundwater and surface water).

Water use in the ACT Management Area is dominated by urban water supply and represents approximately 95% of the total licensed use. Irrigation and rural use is around 3 GL representing the remaining 5% of the total use. In addition there is some unlicensed water use for stock and domestic purpose.

Please note: The tables set out below detailing Level 1 and Level 2 water use categories. The sum of the Level 2 water use volumes will not necessarily equal the total Level 1 water use volumes. This is primarily due to lack of more detailed water use data. However, where Level 2 use = Level 1 use then blank cells in the table does not indicate water use unaccounted for in these categories. 

Map of total surface water use in 1996 Legend for reliability map

Table: Surface water use in Australian Capital Territory 1996-97

Basin/SWMA NameIrrigation (GL/yr)Rural (GL/yr)Urban / Industrial (GL/yr)Total (GL/yr)In-situ (GL/yr)
Australian Capital Territory416368no data
Murrumbidgee River A 11no data1no data
Murrumbidgee River B 115152no data
Murrumbidgee River C 311216no data
Map of surface water use for irrigation in 1996 Map of areas where surface water allocation is greater than sustainable yield

How are Australian Capital Territory's groundwater resources used and allocated?

There is little reliable information on the usage of groundwater resources or their extent in the GMU. Estimates of current use are around 5 GL per year. No information is available on the break up between uses. Under the Water Resources Act 1998 all operational bores in the ACT require a licence. In the NSW part of the GMU all bores are licensed. Groundwater use is, and will continue to be, mostly in 410.b and 410.c. There is little demand in GMU 410.a in light of the permitted land use, predominantly national park and forestry.

The estimation of sustainable yield for groundwater in the GMU's has been made taking account of environmental requirements and is therefore substantially less than the maximum sustainable yield.

Total recharge in the GMU's is calculated to average 73.1 GL per year. The ACT Environmental Flow Guidelines and the Water Resources Management Plan recognise that there are links between groundwater and surface water which need to be considered when determining allowable extraction. In particular, on a regional scale, groundwater is a major contributor to the base flow of rivers and streams. Intensive use of groundwater is likely to lead to significant stress on these waterways.

In this context, the ACT takes a conservative approach to groundwater management, particularly in light of the absence of reliable information. Groundwater abstraction in the ACT has therefore been limited to 10 percent of average annual estimated recharge. Over the entire GMU this is around 7 GL per annum. 

"GMU"=Groundwater Management Unit "UA"=Unallocated Area

Province Use in 1983-84 (GL /yr)Use in 1996-97 (GL /yr) % changeCurrent Alloc (GL/yr)Current Use : Alloc (%)GMU / UA
Australian Capital Territoryno data5 no data8 66 GMU
no datano dataUA
Lachlan 122517953834GMU
710UA
Map of total groundwater use in 1996 by province Map of groundwater allocated volume Chart of total groundwater use by use class

Table: Groundwater use in Australian Capital Territory 1996-97

ProvinceIrrigation (GL/yr)Rural (GL/yr)Urban / industry (GL/yr)In-situ (GL/yr)Total (GL/yr)SY (GL/yr)
Australian Capital Territory24 no data1 5 103
Lachlan 14150352261,491
Map of groundwater use for irrigation in 1996 by groundwater province

Surface and groundwater interactions

All groundwater use to date in the GMU has been developed privately and it is on a relatively small scale. While groundwater use and availability is important on a local scale, no significant scheme is anticipated. There are, however, individual enterprises which integrate groundwater and surface water use and there is potential for groundwater supplies to replace, and possibly in times of drought augment, water use through the urban water supply network.

Further information

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