Let us go by Sydney experience
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Multiple sourcing is clearly seen as the only way and public participation the only alternative
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Photo: K. Manikandan
Improving quality: Waste water recycling is one way of ensuring sustainable supply.
The failing of the monsoon in June this year, the apparent increased melting of the Himalayan glaciers all linked to climate change or maybe not but all cause for concern when urban areas have become increasingly fragile and unable to cope with even a small change in the availability of water.
How are cities across the world coping with resource shortage or the likely impact of a fluctuating climate?
Let us look at Sydney. Australia has faced the big dry for some years, lack of rainfall and falling levels in the major dams especially since rainfall has been below normal in these inland catchments for the last decade and more. Sydney has responded with the Water4 life programme.
Water4life
Picking on the for/four homophone – words that are spelled differently but sound alike- Sydney puts out its four answers for sustainable water supply – Dams, recycling wastewater, water efficiency through demand management and finally desalination.
Dams which stored rainwater in inland catchments will continue to provide the bulk of the water but will steadily decline as a proportion. These reservoirs will account for 49% of the total water demand of the city.
Recycling wastewater has been taken up with the twin benefits of treating a polluting stream but also providing and substituting for fresh water. Though it is technically possible to take the water quality of treated wastewater up to potable levels, Sydney has chosen to use it for non-potable purpose and especially for industrial process use. One success story has been working with its largest industrial consumer and bringing in water efficiency in the system but also providing treated wastewater. Recycling will account for about 12% of greater Sydney’s water requirement by the year 2015.
Water efficiency through demand management will save about 24% of the total water demand or about 145 billion litres of water annually. This demand management exercise occurs through understanding every type of demand and focusing on optimising it through such initiatives as encouraging water efficient flushes through a discount scheme, pushing water efficient washing machines, encouraging mulching and wise landscaping practice, subsidising efficient showerheads but primarily understanding water demand and working together with consumers in a partnership to be efficient. Since Sydney has no pronounced aquifer rainwater harvesting has been pushed through incentivising rainwater tanks to be placed to collect and store the 1200 mm rain that falls annually and to use that for gardening which is one of the highest component of domestic demand.
Climate proof
Desalination is seen as the ultimate ‘climate proof’ water. The desalination plant in Sydney will provide about 15 % of the total water demand. A huge debate took place around the costs, efficiency and environmental impact of desalination plants. Though the debate is not fully settled the decision to go ahead with desalination has been taken and the plant and the distribution system are under construction.
City utilities all around the world are moving to understand their consumer and water demand and then to look at sources of sustainable supply to cater to this water requirement. In the bag of tricks rainwater harvesting, groundwater recharge and management, wastewater treatment and recycling, desalination and demand management all feature. However the biggest change seems to be on how multiple sourcing is clearly seen as the only way to go and that public participation plus engagement is the only alternative.
Utilities in India will need to learn from these experiences and change from within institutionally first so as to be able to cope with the challenges. Climate change will have a profound impact on water resource availability and the sooner we disperse risk the better for our water and sanitation systems.
www.rainwaterclub.org
www.arghyam.org
e-mail:zenrainman@
gmail.com
Phone: 080-23644690
S.VISHWANATH
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