Land and Water Link
September 2002
National Bid to Save Water
Australia, the world's driest inhabited continent, ought to be a world
leader in water
conservation and re-use and a top exporter of related technology and
know-how, according to Dr Peter Dillon of CSIRO Land and Water.
'We currently waste close to 92% of city run-off and 86% of our effluent
water', Dr Dillon says.
'It is time to develop a national approach to doing it better. Lack of
coordination in addressing the barriers to re-use of stormwater and water
reclaimed from treated sewage effluent is impeding progress.'
'There is no national body or funding organisation dedicated to water
re-use, despite unanimous support for the idea from the Australian
Water Association's Water Recycling Forum.'
Australia's poor record on water re-use is slowly changing. Over the past
four years national re-use of effluent, for example, has doubled to 14%
of all effluent produced as a result of $300 million in capital works
investments around the country. However, this remains a small proportion
of the amount of water still running to waste.
In addition to conservation of rainwater, there are four kinds of water
with potential for re-use: stormwater, treated effluent, treated industrial
discharges, and 'grey' (or household laundry and bathroom) waste water.
These could be used for irrigation of city parks, road verges, ovals and
horticulture, for industrial purposes, for cooling water, and for environmental
purposes.
Dr Dillon says that Australia can save up to $5 for every 10 kilolitres
of water it recycles, making a national water re-use research fund a sound
investment.
One of the promising areas for investigation is the idea of 'underground
dams' – the storage and cleansing of surplus surface water in aquifers
under our cities, so it can be used to irrigate parks and gardens during
dry seasons.
Underground dams can be used to harvest city stormwater runoff and save
it to irrigate parks, sports ovals, golf courses and gardens during the
dry season. With further research and development we are confident that
they will provide drinking water for communities. Treated urban sewage
effluent can be harvested and stored in these underground dams, improving
it to a level safe for watering crops or the urban landscape.
Dr Dillon points out that underground dams also offer a means of providing
water security to fast-growing suburbs and industry on the outer metropolitan
fringe, without building new dams. 'They have the potential to save on
capital investment in water storage infrastructure while saving riverine
environments and productive land. These complement surface water dams,
and suitable aquifers are much more common than dam sites.'
Water losses from evaporation could be reduced – for example by capturing
surplus water from rare floods in arid regions to recharge natural aquifers.
In hot, arid areas (like the Western Australian Goldfields) precious water
could be stored underground for re-use by the mineral processing industry
or for greening townships.
At some sites saline groundwater has been made irrigable and even drinkable,
by blending it with fresh water harvested on the surface.
'However,' adds Dr Dillon, 'the water harvesting and storage situation
is likely to vary significantly from city to city, and will therefore
require investigation at the national level as well as a local perspective.'
Re-use is only one of a number of integrated urban water management initiatives
that Australia needs. In some cities it may not be an option. Better urban
planning to reduce demand, water-sensitive urban design, conserving water
in homes and industries, making water use more efficient, and changing
water pricing structures all have a role – alongside water re-use.
CSIRO's
urban water projects are addressing this broader
framework, so that the role of re-use can be better targeted.
'The fact that we re-use less than 10% of the potentially available urban
water is a reflection of our failure to get our act together on this vital
national issue', Dr Dillon concludes.
'Water will be in critically short supply for more than a third of the
earth's population during the 21st century. By solving our own problems
we will not only help Australia – we can also contribute ideas and
technologies to address one of the most vital aspects of human survival.'
For further information
Contact
Dr
Peter Dillon
Ph: 08 8303 8714
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