ALM Note: Are we always in drought?

Derek Eamus ,Director ,Institute for Water and Environmental Resource Management
University of Technology, Sydney,has spoken recently about the need for change in the way in which we manage water in Australia. The bottom line is that across the board we are using more than we receive. According to Dr Eamus,

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?Australia receives about 3.3 million gigalitres of rainfall per year. . The problem is, about 3.0 million gigalitres of water is lost as evaporation from soil and vegetation each year. That?s 90 % lost into the atmosphere. The remaining 10 % disappears as river flow from the land.
Australia therefore appears to have a zero, or even a negative rainfall deficit, ....., input (rain) is equaled by loss (river flow plus evaporation); this is before we even think about consumption by industry and domestic use. How, therefore, can we drink and irrigate the quantities we do?

The average Australian consumes about 1.2 million litres of water per person per year. Annually Australia uses about 22,000 gigalitres of water (about 10 % of the volume we lose as river flow). Where does all this water come from if 90 % of rainfall is lost to evaporation and 10 % to river flow to the oceans??

Whilst water consumption in urban landscapes represents only a small portion of this consumption, these figures demonstrate that action is required to permanently change our consumption patterns. Fundamentally for urban landscapes this means changes to both the nature of vegetation and the way in which we manage it. If we define drought conditions for plants as soil moisture deficit then for most of Australia we know that this occurs every summer. That is we should be expecting drought conditions and planning to provide sustainable vegetation with minimum supplementary irrigation at all times.

Further information can be found at:

http://www.iwerm.uts.edu.au/docs/The%20Australian%20Dream%20-%20a%20summary.pdf


http://www.sustainability.uts.edu.au/research/environment/werm.html