Water Use in Australia

Points covered:

• Where are Australia's water resources located?
• What products use the most water?

Australia is a dry country with limited water resources. The major water resources are in northern Australia and Tasmania, whereas most of our agriculture and people are in south-eastern mainland Australia.

With increasing demands on Australia's limited water resources, we must become more aware of how we use water. We must strike a balance between the need for economic productivity and the sustainable use of our water resources. In particular, we need to consider what foods to produce, based on how much water they use.

The largest consumser of water are meat and wool. To produce a kilo of beef requires 50,000 to 100,000 litres of water, while a kilo of clean wool requires a staggering 170,000 litres. These figures are even higher when the amount of water lost through drainage and delivery is added. It is time for us to evaluate the use of irrigation for growing such products. Water delivery needs to be very cheap, or wool and meat returns exceptionally high, for these products to be economically viable in the long term.

Some of our crops also use a lot of water. For example, a kilo of wheat uses 715 to 750 litres of water; a kilo of maize uses 540 to 630 litres; rice uses 1550 to 2000 litres and soybeans require 1650 to 2200 litres to yield a kilo of dry beans. Furthermore, many crops are grown in dry areas where up to half the available water evaporates from the soil surface or seeps down too low into the ground for the plant roots to reach it. Irrigation water is often delivered through sprinkler systems which allow evaporation to take place before the water even reaches the soil.

It has been suggested that government subsidies on irrigation water be removed to encourage farmers to use more efficient methods of water delivery and to choose crops that are economically viable and efficient in their water use. With global economic pressures and unwanted environmental consequences, we simply cannot afford to use water inappropriately. Ultimately, we must move towards sustainable agriculture.

Wayne Meyer
Land & Water Unit
CSIRO