Water Cycle Benefits Rainwater Efficiency

Written by peter@uwcs.com.au

October 8, 2016

hh_energy

Household energy use for Victoria and NSW

Stormwater, waterway benefits and water resources benefits of water conservation measures for Australian cities

Peter J Coombes, Michael Smit, Josh Byrne and Christopher J Walsh

Households with rainwater harvesting and water efficient appliances made a profound contribution to Australian society by ensuring that cities did not run out of water during the millennium drought. In spite of this, the value of sustainable households is contested as the memory of drought fades. This investigation used audited metadata from national agencies and water utilities, peer reviewed research, case studies and a systems analysis of Australian capital cities to define the benefits of sustainable buildings.

The key findings of this study confirm that source control measures including rainwater harvesting, water efficient appliances and vegetable gardens at households makes a substantial contribution to the viability of water resources and ecosystems in Australian capital cities. These benefits are demonstrated by the historical water balances from most cities as show, for example, for the Ballarat region – sustainable buildings assisted to halve the city’s mains water demands during drought.

Ballarat water balance

Reduction is mains water demands for Ballarat versus water sources, stormwater runoff and wastewater discharges

We will need to build more than 4 million new Australian homes by 2036, a greater than 50% increase in dwelling stock from 2011.   The prosperity and wellbeing of future generations will rely on those buildings being well designed and efficient to live in. There should be a lot of debate about how we are going to do that.

There has also been a range of comments about the energy efficiency of buildings and BASIX based on results obtained from NatHERS. BASIX provides targets for water and energy efficiency in dwellings that operate within planning regulations. In contrast, NatHERS provides a narrower assessment of a buildings thermal efficiency that operates as part of building approvals.

BASIX was designed to set performance based targets for both water use and greenhouse gas generation, which is a consideration of energy use. These performance targets were based on rigorous analysis of energy and water use data at the postcode level and consider the performance of the whole house, not just the building shell. We used metadata to investigate the performance of households. There are a few surprises as discussed in our Fifth Estate article: Why we need to keep and extend BASIX by Michael Smit and PJ Coombes.

We contrast this analysis with our recent systems analysis of households in Australian Capital Cities and historical data. Water conservation in households including rainwater harvesting and water efficient appliances made a profound contribution to Australian society by ensuring that many cities did not run out of water during the millennium drought. Nevertheless, as the memory of millennium drought fades, the value of sustainable households is contested.

The society benefits of source control and water efficiency was investigated using audited metadata from national agencies and water utilities, peer reviewed research, selected case studies and a Systems Framework analysis of Australian capital cities. The key findings of this investigation confirm the substantial contribution of sustainable buildings to improving the performance of water cycle infrastructure and ecological systems in cities. Source control measures including rainwater harvesting, water efficient appliances and vegetable gardens at households makes a substantial contribution to the viability of water resources and ecosystems in Australian capital cities.

Download the paper from Stormwater2016 by PJ Coombes, Michael Smit, Josh Byrne and Christopher J Walsh here: Water resources, stormwater and waterway benefits of water conservation measures for Australian capital cities.  The presentation can be downloaded here: sustainablebuildings. Our monitoring results for houses in South East Queensland during the drought were presented to the International Hydrology and Water Resources Symposium – download the paper here: SEQHouseholds

 

About
Dr Peter Coombes

Dr Coombes has spent more than 30 years dedicated to the development of systems understanding of the urban, rural and natural water cycles with a view to finding optimum solutions for the sustainable use of ecosystem services, provision of infrastructure and urban planning.

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