Rainwater Harvesting & Climate Change

Urban Water Systems: Drivers of Climate Change?

D J M Flower ¹, V G Mitchell ¹, G P Codner ¹

¹Institute for Sustainable Water Resources & eWater CRC, Department of Civil Engineering, Monash University, Victoria, 3800, email: David.Flower@eng.monash.edu.au

Abstract

Urban water systems contribute to climate change both directly through the fugitive greenhouse gas (GHG) emissions associated with water storage reservoirs and wastewater treatment processes, and indirectly through significant energy and materials consumption. This paper presents the findings of an investigation of the GHG emissions associated with operating a case study urban water system in Melbourne, Australia. It was revealed that the appliances associated with the residential end uses of water were responsible for significantly more GHG emissions than all upstream and downstream operations. These findings led to the conclusions that any project seeking to minimise the energy consumption and GHG emissions associated with urban water systems should: (a) consider the whole system, including the end uses of water, in a holistic application of life cycle thinking, and (b) focus on reducing the energy and water consumption associated with the end uses of water, since this will yield multiple benefits upstream, downstream and at the point of use.

Rainwater Harvesting: A Community’s Technology for
Coping with Climate Change.

J. C. Salas¹

¹ President, International Rainwater Catchment Systems Association (IRCSA). Member from Philippines. kahublagan@pldtdsl.net; orojessie@yahoo.com

Abstract

When climate changes, water movements change and human technology adapts. Studies at the International Rainwater Catchment Systems Association (IRCSA) for the last 25 years seem to prepare the mind, the practice and the business for the coming of such event. The paper shall give a short introduction on how climate change may impact on the lives of people and how does the variation challenge water resource management. The experience of climate variability and the prospect of climate change may change key hydrological variables which could turn to be non-linear and therefore bring surprises to unsuspecting communities. Knowledge that somewhere in the world such extreme event is a regular happening survived by communities, allays fear. This paper will tell the stories and will highlight the use of rainwater catchment systems.

Flood and drought are extreme variations in the water regime and these have posed problems on drinking water, food security, health and sanitation, and poverty alleviation. IRCSA’s international, regional and national conferences sponsored by members have produced papers and reports on local actions that demonstrate the capacity of RWCS in coping with the extreme climate variations. When drought and flood take turns in battering villages and cities, people begin to grapple and scramble for mechanisms that will help them protect life, and property first of all. The present experience of many communities in climate variability and the looming climate change has become not just a perceived threat but a real one measured in terms of losses.

It is appropriate to situate the technology search within a framework of a broader coping strategy. It is helpful to see such technology in the test of the worst scenario and the test of time. Trends and predictions could shed light. As coping is a behavioral and emotional response, expressed hopes and fears, and both local and expert opinions are valuable leads. Realizing the impact of climate change on the world water regime, the rainwater catchment system is given a second look in this paper.

Efficiency of Roof and Traditional Water Supply Catchments Subject to Climate Change

¹School of Environment and Life Sciences, University of Newcastle, Australia. p.coombes@newcastle.edu.au

²BMT WBM, Brisbane, Australia. mebarry@wbmpl.com.au

Abstract

A preliminary analysis has been undertaken to compare the relative efficiencies of traditional centralised water supply strategies with decentralised rainwater harvesting approaches. It is shown that both respond differently to drought and climate change forcing, with decentralised rainwater harvesting systems exhibiting a more uniform performance across these stressors. Sufficient data has been generated to warrant ongoing research and strengthening of these results, and this work will form part of a broader research programme.

N. Mithraratne¹ and R. Vale²

Reticulated water supply systems, standard practice in urban areas, suffer from water losses due to leaks and pipe bursts, and for satisfactory service need a high level of investment and intervention. Due to growing concern over future water shortages in urban areas, localized measures such as rain tanks are being widely promoted as a more sustainable alternative: they can promote improved water management through behavioural changes, thereby reducing the overall consumption.

The two systems, however, vary widely in terms of scale, useful life, and level of service, and it is impossible to assess accurately the relative long-term sustainability performance without a detailed life-cycle analysis. Using the results of a life-cycle study of reticulated supply and rain tanks for urban houses in Auckland, New Zealand, which concentrates purely on the environmental performance, this paper argues that rain tanks may not be the most sustainable option in all situations – while rain tanks are better in some situations, reticulated supply is better in others.

Climate Neutral Water Saving Schemes

Abstract

Sustainable water management is a key consideration for Australian cities including Melbourne. We need to manage our existing supplies wisely to protect our ecosystems with a particular focus on the health of our waterways.