Sense breaks through water debate
Hallelujah! Finally some sense in the water debate.
After the rush to build desal plants around the country in the grip of the last drought, a new report in Victoria finds this: “the current system does not adequately support the use of alternative water sources (e.g. rainwater and storm water) for non-drinking needs”.
The Living Melbourne, Living Victoria report must be music to the ears of the many voices who have been banging on for years and years about capturing and re-using rainwater.
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This report might have been produced for Melbourne, but it should be read by urban planners across Australia.
Among a raft of other suggestions, the findings push for stronger building controls to catch stormwater at its source and store it – in some cases in rainwater tanks at properties, and in others in storage tanks big enough for a whole urban precinct.
When we have situations where more storm water flows out of a city each year than the city consumes (as is the case in Melbourne), it does seem crazy not to be tapping into the stuff as it falls from the sky.
The strategy aims to reduce the demand for mains water by using stormwater for non-drinking functions such as flushing toilets and washing clothes, and continues to support greater water efficiency in homes through low-use appliances and tap fittings.
The report suggests improved standards should apply to all new and significantly renovated buildings in Victoria.
The report models the outcomes of capturing more storm water and provides some interesting insights.
One of the scenarios uses a combination of enhanced household water efficiency and rainwater tanks to provide water for toilets, laundry and gardens. In this scenario, mains water was assumed to be used for personal washing and in the kitchen.
The modelling estimated these changes would cut potable water demand by 24 per cent, and lead to a 9 per cent drop in stormwater runoff and an 11 per cent fall in the amount of wastewater being discharged across greater Melbourne by 2050.
In another scenario, domestic rainwater was used for hot water and laundry, while storm water was collected and stored at a precinct or suburb-level, and supplied to households for toilet flushing and gardens.
The modelling shows the above would deliver a 38 per cent cut in mains water demand, an 11 per cent drop
in stormwater runoff and a 32 per cent fall in the wastewater being discharged across greater Melbourne by 2050.
Putting the argument for better water collection in residences, the report noted that larger infrastructure, such as dams and desal plants had a “lumpy, long lead time” and run “much higher risks of saddling customers and/or taxpayers with excessive or unneeded investment” – as many residents across Australia are arguing they are now finding with various desalination plants.
Do you think it makes sense to collect rainwater in homes, or local storage facilities? If not, why not?