1301.0 - Year Book Australia, 2009–10  
ARCHIVED ISSUE Released at 11:30 AM (CANBERRA TIME) 04/06/2010   
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Contents >> Land, biodiversity, water and air >> Murray-Darling Basin (Article)

FEATURE ARTICLE: MURRAY-DARLING BASIN

The Murray-Darling Basin is located in the south-east of Australia (map 3.17). The Basin covers 1,059,000 square kilometres or 14% of Australia's land area. It includes the Australian Capital Territory, and parts of Queensland (15%), New South Wales (75%), Victoria (60%) and South Australia (7%). The Basin contains Australia's three longest rivers, the Darling (2,740 km), Murray (2,530 km) and Murrumbidgee (1,690 km). Significant proportions of the Basin's area are comprised of agricultural land (67%) and native forest (32%).

3.17 THE MURRAY-DARLING BASIN


The climate of the Murray-Darling Basin is relatively dry compared to other regions of Australia (map 3.18). Annual rainfall in 2005-06 was lower in the Murray-Darling Basin than in the tropical north, eastern seaboard and south-west of the continent, as well as in Tasmania. However, most of the Basin received more rainfall than central Australia.

3.18 TOTAL RAINFALL - 2005-2006


Based on long-term averages, the Murray-Darling Basin receives 530,618 GL of annual rainfall. Of this, 94% evaporates or transpires, 2% drains into the ground, and the other 4% becomes run-off (table 3.19).
3.19 Annual water balance- 2008

Murray-Darling Basin
Australia


Volume
Proportion of
rainfall
Volume
Proportion of
rainfall
Water balance component
GL
%
GL
%

Rainfall
530 618
100
3 704 913
100
Evapotranspiration
497 290
94
3 291 649
89
Run-off
23 609
4
349 431
9
Deep drainage
9 719
2
63 833
2

Source: Bureau of Rural Sciences, 2008, Rural Water, viewed 9 July 2008, http://adl.brs.gov.au/water2010
Note: Components may not add to rainfall total due to rounding. Data relates to long-term averages, and is not indicative of a single period of time.


The latest 2004-05 figures show that industries (including agriculture) and households in the Murray-Darling Basin accounted for more than half (52%) of Australia's total water consumption. Agriculture was the largest user of water in 2004-05 in the Murray-Darling Basin, accounting for 83% of water consumption in the Basin; households (2%) and other industries (2%) consumed minor amounts in comparison. The remaining 13% of total water consumed in the Murray-Darling Basin was by the water supply industry, which includes losses in delivery systems (graph 3.20).

3.20 Water Consumption in the Murray-Darling Basin - 2004-05
Graph: 3.20 Water Consumption in the Murray-Darling Basin—2004–05


In the Murray-Darling Basin, water is also an essential production input for the electricity and gas industry. In 2004-05, approximately 3% of Australia's electricity and one-third (33%) of the nation's hydro-electricity was generated in the Murray-Darling Basin. Hydro-electricity represented the bulk of the Basin's generated electricity. Approximately 15,900 GL of water was used (non-consumptively) in the Murray-Darling Basin to generate 5,209 gigawatt hours (GWh) of hydro-electricity. The volume of water used in the Murray-Darling Basin represented 27% of Australia's hydro-electricity (in-stream) water use.

Agriculture water use data are available up to 2007-08, however, data on the use of water by source are only available for 2005-06 and 2006-07. The main sources of water used by agriculture in the Murray-Darling Basin were surface and ground water (graph 3.21). These two sources combined accounted for 98% of all water consumed for agricultural production in the Basin. Other sources accounted for the remaining 2% of water consumption, including recycled or reused water from off-farm sources and reticulated mains supply.
In 2005-06, total agricultural water consumption in the Murray-Darling Basin was 7,720 GL, however in 2006-07 water consumption dropped by 38% to 4,772 GL. Due to dry conditions in 2006-07 use of surface water dropped to 3,323 GL, a 49% decrease compared to 2005-06 levels. Agricultural use of ground water increased to 1,338 GL (up 25%) and use of other water sources decreased to 111 GL (down 27%).

3.21 Sources Of Agricultural Water, Murray-Darling Basin - ^2005-06 to 2006-07
Graph: 3.21 Sources Of Agricultural Water, Murray-Darling Basin—^2005–06 to 2006–07


In 2007-08, irrigated agricultural water consumption in the Murray-Darling Basin was 3,142 GL, a drop of 1,317 GL (30%) compared to 2006-07 (table 3.22). The agriculture commodities that had the most water applied in the Murray-Darling Basin in 2007-08 were: cereals for grain and seed, excluding rice (26%), pastures, cereals and other crops used for grazing (21%) and grapes (14%). The Basin accounted for all irrigated water consumption in Australia for rice (100%), and the vast majority for cotton (91%), cereals to grain or seed, excluding rice (84%) and grapes (84%).

3.22 PASTURES AND CROPS IRRIGATED, MURRAY-DARLING BASIN

2005-06
2006-07
2007-08
GL
GL
GL

Pasture, cereal and other crops used for grazing
2 022.2
1 133.6
656.8
Pasture, cereal and other crops used for hay
648.8
468.8
340.6
Rice
1 251.9
239.4
26.7
Cereals for grain and seed (excluding rice)
623.7
571.8
805.3
Cotton
1 574.4
818.8
282.6
Sugar cane
-
-
-
Pastures for seed
25.2
74.0
n/a
Other broadacre crops
117.7
61.0
85.3
Fruit and nuts
412.7
417.1
356.1
Vegetables for human consumption and seed
152.0
124.9
124.0
Nurseries, cut flowers and cultivated turf
12.2
12.7
9.4
Grapes
514.8
533.9
433.9
Other pastures and crops not elsewhere classified
14.3
2.3
21.1
Total volume applied
7 369.8
4 458.3
3 141.7

- nil or rounded to zero (including null cells)
Source: ABS Water Use on Australian Farms, 2007-08 (4618.0); ABS Experimental Estimates of Gross Value of Irrigated Agriculture Production, 2000-01 to 2006-07 (4610.0.55.008).
Note: Components may not add to volume total due to rounding.

The volume of water used by the agricultural sector for crops and pastures varies from year to year. This is due to a variety of reasons such as: level of rainfall, volume of water available for irrigation (water allocations), technological improvements in irrigation infrastructure, water trading, input costs and commodity prices. Between 2005-06 and 2007-08, water consumption by some commodities was more variable than others. For example, water consumption for cotton in the Murray-Darling Basin decreased considerably from 1,574 to 282 GL and rice also decreased from 1,252 to 27 GL.

Water storage levels in large dams located in the Murray-Darling Basin has progressively declined from July 2000 to June 2006. Basin storage levels were relatively high between July 2000 and December 2001 (greater than 50% for this 18 month period). From January 2002, the combined storage level in large dams in the Murray-Darling Basin did not increase above 50% except for a brief period in late 2005. There is a pattern of increased storage in the winter and spring months of almost every year. However, the amplitude and duration of water storage increase varies, and this affects the volume in storage (graph 3.23).

3.23 Water Storage (a), Murray-Darling Basin - July 2000 to June 2006
Graph: 3.23 Water Storage (a), Murray-Darling Basin—July 2000 to June 2006








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