“Wisdom cries out in the street, in the square she raises her voice, at the busiest corner she cries out, at the entrance to the city gates she speaks” Proverbs 1 20-21
At the gates of Melbourne in Federation Square on a busy Friday morning, Dr Peter Coombes presented the arguments for water targets for sustainable buildings in Australia. Dr Coombes is Australia’s foremost expert on integrated water cycle management and he spoke on behalf of the Rainwater Harvesting Association. The science is based on detailed independent modelling developed over decades. The model already works, it has been proven over 10 years in New South Wales through BASIX , allowing rainwater harvesting and water efficient appliances. Rainwater Harvesting is not mandatory under water saving targets but 90% of households choose to use it to meet the targets. By 2050 we can ensure 90% of the dwellings in the country meet water saving targets. Water management in Victoria by 2050 will cost $36B for water, $24B for sewage and $12B for stormwater. The benefits of a water saving policy are massive, reduced operating costs for water utilities, more reliable storage, deferred desalination plants, more natural stormwater management and integrated water cycle management. Estimated savings from a sustainable buildings policy in Melbourne are $6B by 2050.
An important graph in the presentation was a comparison of the actual operating costs/property of Water Utilities in Melbourne over the last five years, which have almost doubled compared to Sydney Water operating costs which are almost static. Something has made an enormous difference and the implication is that part of the picture is the sustainable buildings policy affecting water use after BASIX was implemented in 2004.
Andrew Allan, National President Stormwater Australia, spoke on the implications of smaller rainfall events triggering urban flooding at a much larger scale than previously modelled. Rainwater harvesting at the source provides cumulative catchment benefits that significantly reduce the problems associated with urban impervious surfaces. Andrew pointed out 47% of our local urban waterways are in poor, or very poor condition. If our waterways are sick, how healthy can our cities be, what world are we leaving for our children?
Russell Beatty, principal economist and engineer for Jacobs Australia spoke on the documented successes of the BASIX program, which is cost benefit positive for household owners and the community. Russell also spoke about some of the NSW learnings including the need for Maintenance Guidelines for Rainwater Harvesting. Russell entertained the crowd with some back of the envelope applications of Dr Coombes integrated systems approach. For example Russell calculated that rainwater catchment area was 80 times as effective as dam catchment area in delivering water, and that the benefits of a combined dam storage/rainwater harvesting solution are greater than the benefits of either stand-alone model.
As Dr Coombes noted, there is a great opportunity to grasp an important policy tool and integrate town planning controls with water and energy outcomes, but we need to start now, before the next drought arrives and we are pushed into rushed, expensive solutions.