1301.0 - Year Book Australia, 2007  
ARCHIVED ISSUE Released at 11:30 AM (CANBERRA TIME) 24/01/2007   
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Contents >> Environment and Heritage >> Water use and irrigation

WATER USE AND IRRIGATION

By world standards, Australia is a dry continent with limited freshwater resources, largely due to its variable and unpredictable rainfall. More than two-thirds of the continent is classified as arid or semi-arid, making it the driest inhabited continent - Antarctica is the driest continent. Low population density means Australia has more fresh water available per person than many countries. However, Australia has one of the world's highest levels of water abstractions per person - the fourth highest of the OECD countries after the USA, Canada and New Zealand.

By far the largest consumer of water in Australia is the agriculture industry. Agriculture accounted for about two-thirds (67%) of total water consumption in 2000-01 (graph 24.23). Of the water used for agricultural production in 2004-05, most was for irrigation of crops and pastures (90%), the remainder was used for other agricultural purposes such as stock drinking water and piggery cleaning.

The second highest consumer of water is households, which accounted for 9% of total water use in 2000-01 (see Household water conservation practices). The water supply, sewerage and drainage services industry is also a significant consumer of water, accounting for 7% of total water consumption, followed by the electricity and gas supply industry which consumed 6.8% excluding in-stream water use for hydro-electricity generation. Mining accounted for 1.6% and manufacturing for 3.5% of total water use in 2000-01.

24.23 WATER CONSUMPTION, By industry - 2000-01 24.23 WATER CONSUMPTION, By industry - 2000-01


In 2004-05, 35,244 farms irrigated, applying a total of 10,085 gigalitres (GL) of irrigation water to 2.4 mill. ha (table 24.24). The area of crops and pastures irrigated is less than 1% of total agricultural land holdings. However, irrigated agriculture represents about 28% of the gross value of agricultural production.


24.24 IRRIGATION WATER USE - 2004-05

Agricultural
establishments
irrigating
Area
irrigated
Volume
applied
Application
rate
no.
'000 ha
'000 ML
ML/ha(a)

New South Wales(b)
8,606
910
3,716.6
4.1
Victoria
9,828
636
2,363.8
3.7
Queensland
8,258
542
2,613.4
4.8
South Australia
4,739
184
877.8
4.8
Western Australia
2,049
45
267.1
6.0
Tasmania
1,654
86
231.8
2.7
Northern Territory
110
4
14.2
4.0
Australia
35,244
2,405
10,084.6
4.2

(a) Averaged across all irrigated pastures and crops.
(b) Includes Australian Capital Territory.
Source: Water Use on Australian Farms, 2004-05 (4618.0).


Some crops are almost totally dependent on irrigation, while for others irrigation water supplements natural rainfall or provides moisture at critical periods of plant growth. ‘Pasture for grazing’ used the most water in 2004-05 (table 24.25). It accounted for nearly one-third of the total volume of irrigation water and also for one-third of the total area irrigated.

The most heavily irrigated crop in terms of the volume of water applied was rice, which had an average application rate of 12.1 megalitres per hectare (ML/ha) in 2004-05. This was almost three times the average rate across all crops and pastures (4.2 ML/ha). Cotton had the next highest application rate (6.7 ML/ha), followed by sugar cane (5.5 ML/ha).


24.25 PASTURES AND CROPS IRRIGATED - 2004-05
Agricultural
establishments
irrigating
Area
irrigated
Volume
applied
Application
rate
no.
'000 ha
'000 ML
ML/ha(a)

Pasture for grazing
12,101
842
2,896.5
3.4
Pasture for seed production
541
33
116.4
3.6
Pasture for hay and silage
4,449
151
579.3
3.8
Cereal crops cut for hay
910
33
80.2
2.4
Cereal crops for grain or seed(b)
2,329
309
814.4
2.6
Cereal crops not for grain or seed
710
19
52.9
2.8
Rice
774
51
619.0
12.1
Sugar cane
2,264
213
1,171.9
5.5
Cotton
668
270
1,819.3
6.7
Other broadacre crops(c)
937
63
177.3
2.8
Fruit trees, nut trees, plantation or berry fruits(d)
6,500
122
608.1
5.0
Vegetables for human consumption
3,791
109
419.2
3.8
Vegetables for seed
416
5
15.1
2.9
Nurseries, cutflowers or cultivated turf
2,656
14
66.3
4.7
Grapevines
6,808
147
591.9
4.0
Total(e)
(f)35,244
2,405
10,085
4.2

(a) Averaged across all irrigated pastures or crops.
(b) Excludes rice.
(c) Excludes sugar cane and cotton.
(d) Excludes grapevines.
(e) Totals include other pastures or crops not elsewhere classified.
(f) Total does not equal the sum as many establishments grow or irrigate more than one crop.
Source: Water Use on Australian Farms, 2004-05 (4618.0).


In the period since about the mid-1950s, there has been a rapid increase in the total area irrigated.

The increase in the irrigated area corresponds with the growth in total dam capacity (graph 24.26). Irrigation requires a dependable supply of water, something which cannot be supplied by the majority of Australian rivers because of the great variability in their flows. Dams have been built since the late-1800s to provide a reliable water resource for irrigation, urban water needs and hydro-electric power generation. At the start of the 20th century the combined storage capacity of all large dams was 250 GL, increasing to 9,540 GL by 1950 and 84,793 GL in 2005. Australia now has the highest per capita water storage capacity in the world, more than 4 mill. litres per person.

24.26 TOTAL WATER STORAGE CAPACITY OF LARGE DAMS


The Murray-Darling Basin dominates irrigation in Australia and accounts for more than 70% of irrigation water use in Australia. The Basin extends over three-quarters of New South Wales, more than half of Victoria, significant portions of Queensland and South Australia, and the whole of the Australian Capital Territory.

In the last 100 years, the Murray-Darling Basin has been transformed by the construction of major water storages on the Murray and Darling Rivers and their tributaries. The total volume of water storage capacity of major dams in the Basin is nearly 35,000 GL.

Today, the Murray-Darling Basin is Australia's most important agricultural region, accounting for more than 40% of the nation's gross value of agricultural production. It supports a quarter of the nation's cattle herd, half of the sheep flock, half of the cropland and almost three-quarters of its irrigated land.



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