Water resources, stormwater and waterway benefits of water conservation measures for Australian capital cities
Peter J Coombes, Michael Smit, Josh Byrne and Christopher J Walsh. Presentation at Stormwater 2016 Conference: 2:15 pm on Thursday 1 September 2016
Water conservation and source controls at households includes rainwater harvesting and water efficient appliances. These approaches 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.
In 2014, more than 1.12 million households in capital cities included rainwater harvesting and water efficient appliances to provide over 125 GL of water savings at a value of greater than $400 million to households. These average annual savings in reduced water bills are $355 per household. These households also reduced greenhouse gas emissions by up to 350,000 tonnes and provided net present benefits for water security of over $483 million. The water security benefit of sustainable buildings was more than $429/household. These households also contributed to protection of urban waterways by substantial reductions in stormwater runoff volumes (65 GL) and contaminant loads (TSS: 13,040 tonnes/year; TP: 25 tonnes/year; TN: 172 tonnes/year).
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. The case studies presented in this paper also demonstrate that sustainable buildings and households operate as integrated systems to produce synergistic and accumulative benefits for water conservation, protection of waterways, improving the performance of infrastructure, and decreasing impacts on ecosystems.