Domestic Water End Use Study: An Investigation of the WaterSavings Attributed to Demand Management Strategies andDual Reticulated Recycled Water Systems
Author
Willis, Rachelle M
Published
2011
Thesis Type
Thesis (PhD Doctorate)
School
Griffith School of Engineering
DOI
https://doi.org/10.25904/1912/916
Copyright Statement
The author owns the copyright in this thesis, unless stated otherwise.
Downloaded from
http://hdl.handle.net/10072/367759
Griffith Research Online
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DOMESTIC WATER END USE STUDY: AN
INVESTIGATION OF THE WATER SAVINGS ATTRIBUTED TO DEMAND MANAGEMENT STRATEGIES AND DUAL RETICULATED
RECYCLED WATER SYSTEMS
RACHELLE M. WILLIS B.Eng (Hons 1)., Grad Cert. Research Mgmt.
GRIFFITH SCHOOL OF ENGINEERING
SCIENCE, ENVIRONMENT, ENGINEERING AND TECHNOLOGY GRIFFITH UNIVERSITY
SUBMITTED IN FULFILMENT OF THE REQUIREMENTS OF THE DEGREE OF DOCTOR OF PHILOSOPHY
AUGUST 2010
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Acknowledgements
It has been quite a pleasure undertaking this PhD due to the positive and supportive people who
have been involved. First and foremost, I would like to sincerely thank my Griffith University
supervisors, Dr Rodney Stewart and Dr Philip Williams, and my Gold Coast Water manager,
Bill Capati, for their encouragement and support. Dr Stewart’s unrelenting time, guidance,
mentoring and energy significantly enabled such an extensive body of work to be undertaken. I
am very grateful to have had such an excellent supervisor. Bill Capati’s drive, support and
enthusiasm significantly facilitated my progress and ensured the wide distribution and
promotion of this body of work. Without Bill’s support, this work could not have occurred nor
would it have been so applicable for practical industrial application. Dr Williams has also
provided invaluable guidance throughout my course of study.
I would especially like to thank the Australia Research Council (ARC) for funding my APAI
scholarship and also the industry partners involved in the ARC Linkage Grant, being Gold
Coast Water, the Institute for Sustainable Futures, Wide Bay Water and the Queensland Water
Directorate. Sincere thanks to the Griffith University Centre for Infrastructure Engineering and
Management for my placement, and Gold Coast Water for situating me within the organisation
for the entirety of my industry-based PhD. Thanks also to all the kind Gold Coast residents that
participated in this research, it would not have been possible without you all kindly offering
your valuable time.
I am also indebted to many Griffith University and Gold Coast Water colleagues and friends. To
Dr Kriengsak Panuwatwanich for all his assistance, input and expertise with paper publications,
especially with statistical analysis. Thanks to Lisa Rutherford, Sarah Jones and Scott Emmonds
(GCW - Demand Management) who have all significantly contributed to the development and
success of the Gold Coast Watersaver End Use Project through project management, day-to-
day support and encouragement. To the GCW ‘Shed Crew’ who brighten up every work day at
GCW through excellence conversion, friendship, coffee run’s and general camaraderie. To
fellow PhD candidate, Tracy Britton and all the Griffith University masters and undergraduates
that assisted me through their thesis and IAP projects, thank you. It has been a pleasure working
with you all.
I also wish to thank all my dear friends who make up our beautiful ‘Brissy Family’. Each and
every one of you has provided me with amazing support, superb friendship and very welcome
distractions throughout this journey. To the wonderful girlfriends who have always been there
walking alongside me, providing friendship and an understanding that never fails and will
Domestic End Use Investigation: WDM and Dual Reticulation, R.M. Willis (2010)
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always remain strong. Such excellent friends are rare indeed, and while you are now distributed
far and wide across this beautiful planet, you remain in my thoughts daily. I look forward to
future adventures with all of you.
To my dearest Mum, Dad and brother, who have supported me from the start and remain the
most amazing family one could wish for. Thank you for your unrelenting love, friendship and
encouragement throughout my life and for the rest of it. I could not imagine a better family. Last
but by no means least, to my wonderful partner Ryan. You have been my backbone for so many
years providing unconditional love, friendship, patience, laughter and encouragement when I
have needed it most and you have seen me through the entirety of this exhausting journey.
Thank you for making everyday a better one, I could not have completed this without you.
As a final note, I would like to dedicate this work to Annette Atwood, a beautiful friend who is
dearly missed. Your aspirations, dreams and memories are carried with me. Water is
fundamental for life. Misuse and over consumption of this precious resource will only result in
ruin. One can only hope that this research adds some of the much needed empirical support and
inspires further sustainable management and consumption of our most precious resource.
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List of Publications
The following papers were produced to disseminate concepts and results from the work
undertaken by the author during the course of this Ph.D. research study.
Journal Publications
1. Willis, R.M., Stewart, R.A., Williams, P.R., Hacker, C.H., Emmonds, S.C. & Capati, G.
(2011) Residential potable and recycled water end uses in a dual reticulated supply system.
Journal of Desalination. Vol 273:1-3, May 2011, pp. 201-211. DOI:
10.1016/j.desal.2011.01.022 (In-press, accepted January 2011). [Chapter 10]
2. Willis, R.M., Stewart, R.A., Panuwatwanich, K., Williams, P. & Hollingsworth, A. (2011)
Quantifying the influence of environmental and water conservation attitudes on household
end use water consumption. Journal of Environmental Management (In press, accepted
March 2011). [Chapter 7]
3. Stewart, R.A., Willis, R.M., Giurco, D., Panuwatwanich, K. & Capati, G. (2010) Web-
based knowledge management system: linking smart metering to the future of urban water
planning. Australian Planning, Vol. 47:2, June 2010, pp. 67-74. DOI:
10.1080/07293681003767769 (In-press, accepted April 2010).
4. Willis, R1., Stewart, R.A., Panuwatwanich, K., Jones, S. & Kyrakides, A. (2010) Alarming
visual display monitors affecting shower end use water and energy conservation in
Australian residential households. Journal of Resources, Conservation and Recycling, Vol.
54:12, October 2010, pp. 1117-1127, DOI: 10.1016/j.resconrec.2010.03.004 (In-press,
accepted March 2010). [Chapter 8]
5. Willis, R.M., Stewart, R.A, Giurco, D., Talebpour, M. R., Mousavinejad, A. (2011) End
use water consumption in households: impact of socio-demographic factors and efficient
devices. Journal of Cleaner Production (under review, submitted October 2010). [Chapter
6]
1 Awarded IWA Grand Award for Research Excellence: Sustainable Urban Water Management
Domestic End Use Investigation: WDM and Dual Reticulation, R.M. Willis (2010)
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6. Willis, R.M., Stewart, R.A. & Emmonds, S. (2010) Pimpama-Coomera dual reticulation
end use study: pre-commission baseline, context and post-commission end use prediction.
IWA Water, Science and Technology: Water Supply, Vol 10:3, pp. 302-314, DOI:
10.2166/ws.2010.104 (In-press, accepted January 2010). [Chapter 9]
7. Willis, R., Stewart. R.A., Panuwatwanich, K., Capati, B. & Giurco, D. (2009) Gold Coast
Domestic Water End Use Study. Water Journal of Australian Water Association, Vol 36:6,
pp. 79-85(In-press, accepted August 2009). [Chapter 5]
Conference Papers
1. Willis, R., Stewart, R., Chen, L. & Rutherford, L. (2009) Water end use consumption
analysis into Gold Coast dual reticulated households: Pilot. Australia’s National Water
Conference and Exhibition: OzWater'09, Melbourne Convention & Exhibition Centre,
Melbourne, 16-18 March 2009. Melbourne.
2. Willis, R., Stewart, R., Capati, B. (2009) Closing the loop on water planning: an integrated
smart metering and web-based knowledge management system approach. 10th IWA
Conference on Instrumentation Control and Automation, 15-17 June 2009. Cairns,
Australia2.
3. Willis, R., Stewart, R., Panuwatwanich, K. & Williams, P. (2009) Influence of household
socioeconomic region and resident type on end use water consumption levels. 2nd
International Conference on Water Economics, Statistics, and Finance, International Water
Association, 3-5 July 2009. Alexandroupolis, Greece.
4. Willis, R., Stewart, R. & Emmonds, S. (2009) Pimpama-Coomera Dual Reticulation End
Use Study: Baseline Situational Context and Post-Commission End Use Prediction. 7th
IWA World Congress on Water Reclamation and Reuse, 21-24 September 2009. Brisbane,
Australia3.
5. Willis, R., Stewart, R., Talebpour, M. R., Mousavinejad, A. & Jones, S. (2009) Influence of
Demographics and Behaviour on the Water Saving Potential of Efficient Fixtures. 5th IWA
Specialist Conference on Efficient Use and Management of Urban Water. 25-28 October
2009. Sydney, Australia.
2 Awarded ‘Best Poster’ International Water Association 3 Awarded ‘Best Paper Presented by a Young Water Professional’ International Water Association
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Abstract
Rainfall patterns in Australia have altered in recent decades, with trends of lower rainfall across
densely populated southern areas recorded. Such drastic changes in climatic conditions have
triggered a re-evaluation of traditional techniques and methods to manage urban water demand
and supply. Throughout the nation, movement towards sustainable urban water resource
management is becoming the norm. This water security method involves the planning and
implementation of a range of water supply, demand management and source substitution
initiatives to meet short term demand and provide long term supply security to urban
populations. Examples of these initiatives include: desalinated potable water, water restrictions,
water efficient fixtures, awareness campaigns, dual reticulated recycled water supply and on-lot
rainwater tanks. In the urban water planning and management industry, these initiatives are
relied upon to provide alternative potable supply types and reduce average daily water demand.
Predictions and estimations of the potable water savings attributed to water demand
management and source substitution measures are often assumed and included in city-wide
planning and forecasting documentation. These water demand management and source
substitution measures play a significant part in meeting projected city future demand however,
these initiatives are all too often planned and implemented without validation of actual potable
water savings. Some examples of measuring potential savings through bulk demand reductions
are documented although this often involves further application of estimations for other
influencing factors such as climate, household makeup and leakage. Understanding the actual
potable water savings attributed to water demand management and source substitution
initiatives requires the application of end use water consumption monitoring due to the need to
establish the point of source savings related to these measures.
Significant residential end use water consumption studies have been carried out in Perth and
Melbourne in Australia and, in the United States of America. These investigations have
ascertained the unique consumption behaviours of residents in the monitored location and
presented some examples of measuring water savings attributed to water efficient devices. The
variation in end use consumption between the studies and the useful application of results from
these investigations has prompted the encouragement of further research in this field. To date,
no statistically significant end use water consumption study has occurred in the state of
Queensland, Australia. In response to the current gaps in the body of knowledge, this research
focused on determining end use water consumption and investigating the end use savings
attributed to water efficient fixtures, resource consumption awareness devices, and dual
reticulated recycled water supply regions in the Gold Coast, Australia. This study also
Domestic End Use Investigation: WDM and Dual Reticulation, R.M. Willis (2010)
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investigated the relationship between attitudes towards the environment and water conservation
and the impact that this had on end use water consumption. The research also developed end use
diurnal patterns of consumption for both single and dual reticulated regions on the Gold Coast.
A mixed methods approach was adopted to achieve the above mentioned research objectives.
This explanatory mixed methodology included: the development and application of natural
science research, quantitative survey questionnaires, numerous statistical analysis techniques,
experimental analysis, qualitative behavioural methods and software development. These
methods resulted in the experimental measurement of end use water consumption via high
resolution smart metering technology, at various times over a two year period, which included
before and after the introduction of resource consumption awareness shower monitors and, pre-
and post-commissioning of recycled water to the Pimpama Coomera dual reticulated region.
Water stock surveys and behavioural interviews assisted in developing end use water
consumption patterns and behaviours within homes. Questionnaire surveys determined socio-
demographic characteristics of the research sample and allowed for the development of
constructs to measure environmental and water conservation attitudes.
Due to the array of objectives, methods, data types and results, this thesis has been structured
around significant refereed journal publications produced during the course of the PhD study.
This allowed for unique elements and objectives to be explored and presented through peer-
reviewed journal papers. Two themes emerged from the research being: (1) influence of demand
management on water end uses; (2) and end uses of dual reticulated recycled water supply
schemes. The first theme covered: domestic end use water consumption in the Gold Coast; an
investigation into the impact of socio-demographic and water efficient devices on end use water
consumption; analysis of the effect of environmental and water conservation attitudes on end
use water consumption; and, an experiment to determine the effective water savings attributed
to a resource consumption awareness shower monitor device.
Showering was found to be the highest indoor end use consumer in single detached residential
households. Clothes washing was the next highest followed by tap and toilet use. Leak, bathtub
and dishwasher categories all had relatively small consumption volumes. When irrigation was
included in total end use consumption breakdowns, it was situated fourth after showering,
clothes washing and tap use. The effectiveness of water efficient shower heads and clothes
washing devices was empirically explored with payback periods of less than half a year and 6.5
years determined respectively. Irrigation was halved in properties with rainwater tanks. The
effect of attitudes on total and discretionary end use water consumption was very apparent.
Residents with very high concern for the environment and water conservation and awareness
consumed significantly less total (128.2 L/p/d) and discretionary end use water than those with
Abstract
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moderate concern (169.0 L/p/d). This demonstrated the importance of instilling positive
environmental and water conservation awareness to consumers due to the significant water
savings apparent from such attitudes. The experimental study exploring the effectiveness of a
resource consumption awareness shower monitor revealed significant reductions in shower
volumes, durations and flow rates.
The second phase of research was the dual reticulated recycled water study in the Pimpama
Coomera Waterfuture Master Plan region. This involved the measurement of end use water
consumption pre-commissioning of recycled water, the prediction of consumption post-
commissioning and the monitoring of actual post-commissioning water end use, along with the
development of diurnal patterns of demand. Pre-commissioning recycled water end use was low
due to irrigation volumes being minimal. A predictive uptake model was developed based on
influencing factors reported in the literature including water restriction levels, climatic
influences, price and the uptake of recycled water in other dual reticulated schemes. The
predicted most likely uptake post-commissioning of recycled water to the Pimpama Coomera
region was determined to be 53 L/p/d or 30.5% of total end use. End use water consumption
was monitored post-commissioning in both a low and high consumption period, which allowed
for the formulation of average recycled water end use. Average recycled water uptake in the
Pimpama Coomera region was recorded as 59.1 L/p/d or 32.2% of total end use water
consumption. Of this recycled water use, the end uses of irrigation, toilet and leakage were 28.9,
27.5 and 2.7 L/p/d respectively. Potable water consumption in the dual reticulated region was
124.5 L/p/d or 67.8%. The end use post-commissioning recycled water consumption was almost
the same as that predicted pre-commissioning, irrigation consumption being particularly close.
End use diurnal patterns of consumption varied significantly between the single and dual
reticulated regions with the potable peak hour demand being almost twice as high in the single
reticulated region when compared to the dual reticulated region. This finding demonstrates the
need to undertake validation research to determine the effectiveness of unique source
substitution supply schemes.
The data and results from this extensive investigation into end use water consumption for single
and dual reticulated households in the Gold Coast, along with the measurement of end use water
consumption savings related to water efficient devices, educational prompt devices,
environmental and water conservation attitudes and the application of dual reticulation for
residential use, are highly applicable for industry and academia. This research significantly
contributes to the urban water resource planning and management field through the
determination of empirical data on a range of end use, water demand management and source
substitution initiatives. The results from the study can be readily applied to improve urban water
planning and management and the application of sustainable urban water resource management.
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Table of Contents DECLARATION OF ORIGINALITY.......................................................................................I
ACKNOWLEDGEMENTS......................................................................................................III
LIST OF PUBLICATIONS....................................................................................................... V
ABSTRACT ............................................................................................................................. VII
TABLE OF CONTENTS..........................................................................................................XI
LIST OF TABLES .................................................................................................................. XX
LIST OF FIGURES ............................................................................................................. XXII
LIST OF ACRONYMS.........................................................................................................XXV
CHAPTER 1 ................................................................................................................................ 1
INTRODUCTION....................................................................................................................... 1
1.1 Research Background.................................................................................................................... 1
1.2 Research Objectives and Scope .................................................................................................... 3
1.3 Research Method Overview .......................................................................................................... 4
1.3.1 Knowledge acquisition ......................................................................................................... 6
1.3.2 End use baseline and water demand management ................................................................ 6
1.3.3 Dual reticulated recycled water ............................................................................................ 6
1.4 Thesis Layout ................................................................................................................................. 7
1.5 References..................................................................................................................................... 10
CHAPTER 2 .............................................................................................................................. 13
LITERATURE REVIEW......................................................................................................... 13
2.1 The Water Conditions in Australia ............................................................................................ 14
Domestic End Use Investigation: WDM and Dual Reticulation, R.M. Willis (2010)
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2.2 Water Consumption and Demand Forecasting in Urban Australia........................................ 15
2.3 Gold Coast City’s Solution to the Water Crisis......................................................................... 17
2.4 Integrated Urban Water Resource Management...................................................................... 19
2.4.1 Supply sources.................................................................................................................... 20
2.4.2 Demand management ......................................................................................................... 22
2.4.3 Source substitution.............................................................................................................. 23
2.5 Water Demand Management ...................................................................................................... 23
2.5.1 Water metering ................................................................................................................... 24
2.5.2 Enforcement........................................................................................................................ 25
2.5.3 Water pricing ...................................................................................................................... 26
2.5.4 Engineered water efficient devices ..................................................................................... 27
2.5.5 Education and awareness .................................................................................................... 30
2.6 Source Substitution with Recycled Water ................................................................................. 31
2.6.1 Dual reticulation ................................................................................................................. 32
2.6.2 The Pimpama Coomera Waterfuture Master Plan .............................................................. 32
2.6.3 Overview of dual reticulated schemes in Australia............................................................. 34
2.7 Advanced Water Consumption Monitoring Technologies ....................................................... 36
2.7.1 Smart metering ................................................................................................................... 36
2.7.2 End use studies ................................................................................................................... 38
2.8 Research Justification.................................................................................................................. 42
2.8.1 Water end use and demographics ....................................................................................... 43
2.8.2 Engineered efficient devices, consumer attitudes and water end use.................................. 44
2.8.3 Recycled water end use ...................................................................................................... 45
2.9 Chapter Summary ....................................................................................................................... 45
2.10 References..................................................................................................................................... 46
CHAPTER 3 .............................................................................................................................. 55
RESEARCH METHOD AND DESIGN ................................................................................. 55
3.1 Overview of Research Method and Design ................................................................................ 55
3.1.1 Explanatory mixed method design...................................................................................... 56
3.1.2 Quantitative research .......................................................................................................... 58
3.1.3 Qualitative research ............................................................................................................ 58
3.1.4 Explanatory mixed methods: follow-up explanations model design .................................. 59
3.2 Phase 1: Knowledge Acquisition................................................................................................. 61
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3.3 Phase 2: Water End Use and Demand Management ................................................................ 62
3.3.1 Stage 2a: End use water consumption design ..................................................................... 64
3.3.2 Stage 2b: Obtain consenting sample ................................................................................... 66
3.3.3 Stage 2c: Potable end use water consumption data............................................................. 70
3.3.4 Stage 2d: Stock survey and water use behaviour audit ....................................................... 72
3.3.5 Stage 2e: Potable end use water consumption .................................................................... 73
3.3.6 Stage 2f: Questionnaire development, distribution and analysis ........................................ 74
3.3.7 Stage 2g: Educational shower monitor device.................................................................... 77
3.4 Phase 3: Dual Reticulated Recycled Water................................................................................ 78
3.4.1 Stage 3a: Predictive dual reticulated recycled water uptake model .................................... 78
3.4.2 Stage 3b: Dual reticulated recycled end use data collection and analysis........................... 80
3.4.3 Stage 3c: Dual reticulated recycled water end use consumption ........................................ 81
3.5 Chapter Summary ....................................................................................................................... 82
3.6 References..................................................................................................................................... 82
CHAPTER 4 .............................................................................................................................. 85
SITUATIONAL CONTEXT AND DESCRIPTIVE DATA ANALYSIS............................. 85
4.1 Research Sample Group.............................................................................................................. 85
4.2 Research Sample Characteristics ............................................................................................... 88
4.2.1 Socioeconomic status of areas ............................................................................................ 89
4.2.2 Descriptive statistic characteristics of the total research sample ........................................ 90
4.2.3 Descriptive statistic characteristics of individual research areas ........................................ 92
4.2.4 Comparing single and dual reticulated regions................................................................... 93
4.3 Situational Context of Study ....................................................................................................... 94
4.3.1 Water restriction regimes over the data collection period .................................................. 94
4.3.2 Temperature and rainfall patterns on the Gold Coast ......................................................... 96
4.3.3 Climate, bulk recorded supply and end use data throughout the study period.................... 98
4.4 End Use Water Consumption Data .......................................................................................... 102
4.4.1 Winter 2008 ...................................................................................................................... 102
4.4.2 Summer 2008.................................................................................................................... 105
4.4.3 December 2009................................................................................................................. 108
4.4.4 March 2010....................................................................................................................... 112
4.4.5 Summary of all end use water consumption data ............................................................. 115
4.5 Chapter Summary ..................................................................................................................... 117
4.6 References................................................................................................................................... 117
Domestic End Use Investigation: WDM and Dual Reticulation, R.M. Willis (2010)
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CHAPTER 5 ............................................................................................................................ 118
GOLD COAST DOMESTIC END USE STUDY................................................................. 118
5.1 Abstract....................................................................................................................................... 118
5.2 Introduction................................................................................................................................ 118
5.3 The Gold Coast Watersaver End Use Study............................................................................ 119
5.4 Research Method ....................................................................................................................... 119
5.4.1 End use analysis process in brief ...................................................................................... 121
5.5 Results and Discussion............................................................................................................... 122
5.5.1 Water end use on the Gold Coast...................................................................................... 122
5.5.2 End use comparison with previous studies ....................................................................... 122
5.5.3 End use comparison: percentage or volume?.................................................................... 124
5.5.4 End use comparison for individual households ................................................................ 124
5.6 Conclusion .................................................................................................................................. 128
5.7 Future Work............................................................................................................................... 128
5.8 References................................................................................................................................... 129
CHAPTER 6 ............................................................................................................................ 131
END USE WATER CONSUMPTION IN HOUSEHOLDS: IMPACT OF SOCIO-
DEMOGRAPHIC FACTORS AND EFFICIENT DEVICES ............................................ 131
6.1 Abstract....................................................................................................................................... 131
6.2 Introduction................................................................................................................................ 131
6.2.1 Improving urban water security ........................................................................................ 131
6.2.2 Domestic water consumption and conservation................................................................ 132
6.2.3 Advent of smart water metering ....................................................................................... 132
6.2.4 Overview of Gold Coast End Use Study .......................................................................... 132
6.2.5 Engineered water efficiency ............................................................................................. 133
6.2.6 Influences of socio-demographic factors .......................................................................... 133
6.2.7 Research objectives .......................................................................................................... 133
6.3 Method ........................................................................................................................................ 134
6.3.1 Mixed method study design.............................................................................................. 134
6.3.2 Sample .............................................................................................................................. 134
6.3.3 Water consumption end use study .................................................................................... 134
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6.3.4 Questionnaire survey ........................................................................................................ 135
6.3.5 Household appliance stock survey and water behaviour investigation............................. 136
6.3.6 Water end use analysis and comparison ........................................................................... 136
6.4 Results ......................................................................................................................................... 137
6.4.1 Influence of socio-demographic factors............................................................................ 137
6.4.2 Stock efficiency versus end use consumption................................................................... 140
6.5 Conclusion .................................................................................................................................. 145
6.6 Acknowledgements .................................................................................................................... 145
6.7 References................................................................................................................................... 145
CHAPTER 7 ............................................................................................................................ 148
QUANTIFYING THE INFLUENCE OF ENVIRONMENTAL AND WATER
CONSERVATION ATTITUDES ON HOUSEHOLD END USE WATER
CONSUMPTION .................................................................................................................... 148
7.1 Abstract....................................................................................................................................... 148
7.2 Introduction................................................................................................................................ 148
7.3 Theoretical Background............................................................................................................ 151
7.3.1 Water consumption attitudes and behaviour..................................................................... 151
7.3.2 Water end use monitoring................................................................................................. 154
7.3.3 Research propositions....................................................................................................... 157
7.4 Research Method ....................................................................................................................... 158
7.4.1 Situational context ............................................................................................................ 158
7.4.2 Research sample ............................................................................................................... 159
7.4.3 End use smart metering approach ..................................................................................... 159
7.4.4 Questionnaire development and survey ............................................................................ 160
7.5 Data Analysis and Results ......................................................................................................... 160
7.5.1 Descriptive statistics ......................................................................................................... 160
7.5.2 Measurement model assessment ....................................................................................... 161
7.5.3 Exploration of clusters ...................................................................................................... 164
7.5.4 Water consumption end use analysis ................................................................................ 166
7.6 Discussion ................................................................................................................................... 170
7.6.1 Overview on water consumption and attitudes ................................................................. 170
7.6.2 Linking socio-demographic variables with attitudes ........................................................ 172
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7.7 Conclusions and Implications ................................................................................................... 173
7.8 Acknowledgements .................................................................................................................... 174
7.9 References................................................................................................................................... 174
CHAPTER 8 ............................................................................................................................ 178
ALARMING VISUAL DISPLAY MONITORS AFFECTING SHOWER END USE
WATER AND ENERGY CONSERVATION IN AUSTRALIAN RESIDENTIAL
HOUSEHOLDS....................................................................................................................... 178
8.1 Abstract....................................................................................................................................... 178
8.2 Background ................................................................................................................................ 179
8.2.1 Climate change and improving urban water security........................................................ 179
8.2.2 Domestic water consumption and conservation................................................................ 180
8.2.3 Advent of smart water metering and end use analysis...................................................... 180
8.2.4 Engineered water conservation appliances and fixtures ................................................... 181
8.2.5 Visual display technologies and alarming devices influencing resource conservation
behaviour ..................................................................................................................................... 182
8.2.6 Overview of Gold Coast Watersaver End Use study ........................................................ 184
8.3 Research Objectives................................................................................................................... 185
8.4 Research Method ....................................................................................................................... 186
8.5 Baseline Water Consumption End Use Analysis ..................................................................... 189
8.6 Visual Display Monitors Influencing Shower End Use Events .............................................. 191
8.6.1 Influence on shower duration ........................................................................................... 192
8.6.2 Influence on shower volumes ........................................................................................... 193
8.6.3 Influence on shower flow rates ......................................................................................... 195
8.7 Resource Conservation and Financial Modelling.................................................................... 196
8.7.1 Water and energy conservation......................................................................................... 196
8.7.2 Monetary savings and capital pay-back............................................................................ 197
8.7.3 Wider non-monetary benefits ........................................................................................... 199
8.8 Conclusions and Futures Directions......................................................................................... 200
8.9 References................................................................................................................................... 201
CHAPTER 9 ............................................................................................................................ 204
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PIMPAMA-COOMERA DUAL RETICULATION END USE STUDY: PRE-
COMMISSION BASELINE, CONTEXT AND POST-COMMISSION END USE
PREDICTION ......................................................................................................................... 204
9.1 Abstract....................................................................................................................................... 204
9.2 Australian Dual Reticulated Communities .............................................................................. 205
9.3 Pimpama-Coomera Dual Reticulation Scheme ....................................................................... 207
9.4 Pimpama-Coomera Dual Reticulation End Use Study ........................................................... 208
9.5 Baseline Situation: Recycled Water Pre-Commissioning End Uses ...................................... 209
9.6 Predicting Recycled Water Post-commissioning End Uses .................................................... 211
9.6.1 Predictive analysis approach and input factors ................................................................. 211
9.6.2 Establishing baseline end use situational context ............................................................. 211
9.6.3 Influence of irrigation end use measurements conducted elsewhere ................................ 212
9.6.4 Influence of water restriction levels and changes ............................................................. 213
9.6.5 Influence of customer water source preferences............................................................... 214
9.6.6 Influence of recycled water pricing .................................................................................. 215
9.6.7 Influence of climate .......................................................................................................... 216
9.6.8 Influence of lot size .......................................................................................................... 216
9.6.9 Influence of recycled water awareness campaign............................................................. 216
9.7 Predicting Post-commissioning Dual Reticulation End Uses ................................................. 217
9.7.1 Possibility theory underpinning prediction model ............................................................ 217
9.7.2 Prediction model application ............................................................................................ 217
9.8 Future Research: Post-commissioning Comparative Analysis .............................................. 219
9.9 Conclusion .................................................................................................................................. 219
9.10 References................................................................................................................................... 220
CHAPTER 10 .......................................................................................................................... 223
RESIDENTIAL POTABLE AND RECYCLED WATER END USES IN A DUAL
RETICULATED SUPPLY SYSTEM.................................................................................... 223
10.1 Abstract....................................................................................................................................... 223
10.2 Integrated Urban Water Resources Management .................................................................. 223
10.2.1 Water services planning.................................................................................................... 224
10.2.2 Water end use and diurnal patterns................................................................................... 225
Domestic End Use Investigation: WDM and Dual Reticulation, R.M. Willis (2010)
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10.2.3 Gold Coast’s Pimpama Coomera dual reticulation scheme.............................................. 227
10.3 Objectives and Scope of the Paper ........................................................................................... 229
10.4 Pimpama Coomera End Use Water Consumption Study ...................................................... 231
10.4.1 Pre-Commissioning of recycled water to Pimpama Coomera region ............................... 231
10.4.2 Post-Commissioning of recycled water to Pimpama Coomera region ............................. 233
10.4.3 Comparison of Phase 1 prediction with Phase 2 data ....................................................... 235
10.5 Compilation of end use average hourly diurnal patterns ....................................................... 236
10.5.1 Developed end use diurnal pattern software tool.............................................................. 236
10.5.2 Diurnal patterns of consumption....................................................................................... 236
10.5.3 End use diurnal patterns of consumption.......................................................................... 238
10.5.4 Variation in peaks between single and dual reticulated supply schemes .......................... 240
10.6 Conclusions, Implications and Future Directions ................................................................... 240
10.7 References................................................................................................................................... 242
CHAPTER 11 .......................................................................................................................... 245
CONCLUSIONS, CONTRIBUTIONS AND IMPLICATIONS......................................... 245
11.1 Research Objectives and Outcomes ......................................................................................... 245
11.1.1 Knowledge acquisition ..................................................................................................... 247
11.1.2 Water end use and demand management.......................................................................... 247
11.1.3 Dual reticulated recycled water ........................................................................................ 250
11.2 Study Contributions................................................................................................................... 251
11.2.1 Contributions to existing body of knowledge ................................................................... 251
11.2.2 Implications for water planning and management ............................................................ 253
11.3 Study Limitations and Future Research Directions................................................................ 254
11.4 Closure ........................................................................................................................................ 255
11.5 References................................................................................................................................... 256
REFERENCES........................................................................................................................ 257
APPENDIX A .......................................................................................................................... 271
APPENDIX B .......................................................................................................................... 282
Table of Contents
- xix -
APPENDIX C .......................................................................................................................... 284
APPENDIX D .......................................................................................................................... 288
APPENDIX E .......................................................................................................................... 290
APPENDIX F........................................................................................................................... 296
APPENDIX G.......................................................................................................................... 307
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List of Tables
Table 2-1 Australia’s water consumption by sector 2004-05 (ABS, 2007) ................................ 15
Table 2-2 Gold Coast Waterfuture Water Balance (GCW & GCCC, 2007)............................... 18
Table 2-3 Savings from various WDM measures (Sarac et al., 2002, pp. 7).............................. 28
Table 2-4 Class A+ recycled water uses (GCW, 2009b) ............................................................ 33
Table 2-5 Water use in Pimpama Coomera versus existing communities (Gold Coast Water,
2004) ................................................................................................................................... 34
Table 2-6 Summary of dual reticulated schemes in Australia..................................................... 35
Table 2-7 Summary of findings from other water end use studies.............................................. 41
Table 2-8 Comparison of Asia-Pacific end use water consumption studies ............................... 42
Table 3-1 Strengths and weaknesses of Explanatory Mixed Methods (Creswell, 2008) ............ 57
Table 4-1 Overview of research area and recruited participants................................................. 88
Table 4-2 Overview of research area and socioeconomic status indicators ................................ 89
Table 4-3 Descriptive statistics of research regions.................................................................... 91
Table 4-4 Gold Coast water restriction overview and timeframe ............................................... 95
Table 4-5 Climatic, bulk supply and end use water consumption data from Gold Coast City ... 99
Table 4-6 Winter 2008 end use data for research regions ......................................................... 105
Table 4-7 Summer 2008/09 end use data for research regions ................................................. 107
Table 4-8 Summer December 2009 end use data for research regions ..................................... 111
Table 4-9 March 2010 End use data for research regions ......................................................... 115
Table 5-1 Comparison between national and pacific water end use consumption studies........ 123
Table 6-1 Comparison between national end use water consumption studies (Willis et al.,
2009b) ............................................................................................................................... 137
Table 6-2 Showerhead efficiency cluster comparisons ............................................................. 141
Table 6-3 Clothes washer efficiency comparisons.................................................................... 142
Table 6-4 Rainwater tank cluster comparisons ......................................................................... 143
Table 7-1 Measurement items for concern for environment factor........................................... 153
Table 7-2 Measurement items for water conservation awareness and practice factor............. 155
Table 7-3 Results from domestic end use studies ..................................................................... 156
Table 7-4 Socioeconomic descriptive statistics for sampled regions ........................................ 161
Table 7-5 Measurement items mean value and standard deviation........................................... 162
Table 7-6 Measurement model analysis results ........................................................................ 163
Table 7-7 Clustered comparative analysis results. .................................................................... 170
Table 8-1 Independent sample t-test for equality of means ...................................................... 194
Table 9-1 Summary of dual reticulated schemes in Australia................................................... 206
Table 9-2 PC baseline end use situational context .................................................................... 212
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Table 9-3 Influence of water restriction levels on billed water meter consumption in the Gold
Coast (ML/d) ..................................................................................................................... 213
Table 9-4 PC respondent perceptions on preferred source for outdoor activities (n=70) ......... 214
Table 9-5 Recycled water for irrigation purposes influencing factors and weighted possibility
distribution ........................................................................................................................ 218
Table 9-6 PC recycled water post-commissioning end use prediction...................................... 219
Table 10-1 Summary of findings from other water end use studies.......................................... 226
- xxii -
List of Figures
Figure 1-1 Overarching mixed methods research design.............................................................. 5
Figure 2-1 Overview of reviewed literature topics ..................................................................... 13
Figure 2-2 Factors that influence demand (White and Turner, 2003; WSAA, 2008) ................. 16
Figure 2-3 Gold Coast Waterfuture Master Plan water balance 2007 (GCW & GCCC, 2007).. 18
Figure 2-4 Australian IUWRM framework (Turner and White, 2006)....................................... 21
Figure 2-5 WELS water rating label (Commonwealth of Australia, 2009) ................................ 26
Figure 2-6 Pimpama Coomera Master Plan – household water uses (Gold Coast Water, 2008b)
............................................................................................................................................. 33
Figure 2-7 Typical smart meter set up in residential household (Stewart et al., 2009)............... 37
Figure 2-8 Potential for demand reduction and alternative supply options across scales (Stewart
et al., 2009) ......................................................................................................................... 37
Figure 2-9 Matching technologies to objectives (Giurco et al., 2008a) ...................................... 38
Figure 2-10 Household end uses of water ................................................................................... 39
Figure 3-1 The explanatory mixed methods design (Creswell and Plano Clark, 2007).............. 56
Figure 3-2 Explanatory design: follow-up explanations model (QUAN emphasised) (Creswell
and Plano Clark, 2007)........................................................................................................ 56
Figure 3-3 Overarching mixed methods research design............................................................ 60
Figure 3-4 Phase 1 research activities and output ....................................................................... 61
Figure 3-5 End use measurement study design cycle (Giurco et al., 2008a) .............................. 62
Figure 3-6 Phase 2 research activities and output ....................................................................... 63
Figure 3-7 Stage 2a: End use water consumption design............................................................ 64
Figure 3-8 Stage 2b: Obtain consenting sample.......................................................................... 66
Figure 3-9 Stage 2c: Potable end use water consumption data acquisition testing ..................... 70
Figure 3-10 End use data downloading procedure...................................................................... 71
Figure 3-11 Stage 2d: Stock survey and water use behaviour audit............................................ 72
Figure 3-12 Stage 2e: Potable end use water consumption......................................................... 73
Figure 3-13 Stage 2f: Questionnaire development, distribution and analysis............................. 75
Figure 3-14 Diagram of relationships between dependent and independent questionnaire survey
variables .............................................................................................................................. 76
Figure 3-15 Stage 2g: Shower monitor investigation.................................................................. 78
Figure 3-16 Phase 3: Detailed overview of research activities and output ................................. 79
Figure 3-17 Stage 3a: Predictive dual reticulated recycled water uptake model......................... 80
Figure 3-18 Stage 3b: Dual reticulated recycled end use water consumption data collection and
analysis................................................................................................................................ 80
Figure 3-19 Stage 3c: End use model for dual reticulated recycled water consumption ............ 81
Domestic End Use Investigation: WDM and Dual Reticulation, R.M. Willis (2010)
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Figure 4-1 Research areas for the Gold Coast Watersaver End Use study ................................. 86
Figure 4-2 Research areas and participating households ............................................................ 87
Figure 4-3 Yearly temperature and rainfall patterns for the Gold Coast, Queensland................ 97
Figure 4-4 Average daily per capita consumption for total sample in winter 2008 (n=151) .... 103
Figure 4-5 Average daily per capita consumption for single reticulated region in winter 2008
(n=38)................................................................................................................................ 104
Figure 4-6 Average daily per capita consumption for dual reticulated region in winter 2008
(n=113).............................................................................................................................. 104
Figure 4-7 Average daily per capita consumption for total sample in summer 2008/09 (n=127)
........................................................................................................................................... 106
Figure 4-8 Average daily per capita consumption for single reticulated region in summer
2008/09 (n=29).................................................................................................................. 107
Figure 4-9 Average daily per capita consumption for dual reticulated region in summer 2008/09
(n=98)................................................................................................................................ 107
Figure 4-10 Average daily per capita consumption total sample December 2009 (n=33)........ 109
Figure 4-11 Average daily per capita consumption single reticulated region in December 2009
(n=7).................................................................................................................................. 110
Figure 4-12 Average daily per capita consumption dual reticulated region in December 2009
(n=26)................................................................................................................................ 111
Figure 4-13 Average daily per capita consumption total sample March 2010 (n=100)............ 113
Figure 4-14 Average daily per capita consumption single reticulated region in March 2010
(n=27)................................................................................................................................ 113
Figure 4-15 Average daily per capita consumption dual reticulated region in March 2010 (n=73)
........................................................................................................................................... 114
Figure 4-16 Gold Coast indoor water consumption for entire study period (n=412)................ 116
Figure 4-17 Gold Coast total (indoor and outdoor) water consumption for entire study period
(n=411).............................................................................................................................. 116
Figure 5-1 Gold Coast Watersaver End Use study project schedule......................................... 120
Figure 5-2 Data loggers and collection technique..................................................................... 122
Figure 5-3 Average daily per person consumption (L/p/d): combined sample (n=151) ........... 123
Figure 5-4 Household daily per capita consumption: activity break down............................... 125
Figure 5-5 Household daily per capita consumption: shower only........................................... 126
Figure 5-6 Household daily per capita consumption: irrigation only........................................ 126
Figure 5-7 Average daily per capita water consumption: socioeconomic regions.................... 127
Figure 6-1 Schematic illustrating water end use analysis process ............................................ 135
Figure 6-2 Average daily per capita consumption (L/p/d): combined sample (n=151) ............ 137
Figure 6-3 Impact of socio-demographic area on end use water consumption ......................... 138
Figure 6-4 Impact of lot size and RWT installation on irrigation end use ................................ 139
List of Figures
- xxiv -
Figure 6-5 Impact of family income on water consumption ..................................................... 140
Figure 6-6 Relationships between household resident typologies and water end use consumption
........................................................................................................................................... 140
Figure 7-1 CFA model .............................................................................................................. 164
Figure 7-2 Profiles of clusters’ final centroids.......................................................................... 165
Figure 7-3 Average daily per capita consumption per end use: total sample (n=132).............. 166
Figure 7-4 Household daily per capita consumption distribution with water end use breakdown:
total sample (n=132) ......................................................................................................... 167
Figure 7-5 Average daily per capita consumption: VHC cluster (n=54) .................................. 168
Figure 7-6 Household daily per capita consumption distribution profile: VHC cluster (n=54) 168
Figure 7-7 Average daily per capita consumption: MHC cluster (n=78).................................. 169
Figure 7-8 Household daily per capita consumption distribution profile: MHC cluster (n=78)169
Figure 8-1 Alarming visual display device ............................................................................... 184
Figure 8-2 Sample end use break down: winter pre-retrofit (n=151)........................................ 189
Figure 8-3 Sample household end use distribution: winter pre-retrofit (n=151)....................... 190
Figure 8-4 Sample shower end use distribution: winter pre-retrofit (n=151) ........................... 191
Figure 8-5 Sample pre- and post- monitor retrofit shower event duration frequency distribution
........................................................................................................................................... 193
Figure 8-6 Sample pre- and post- monitor retrofit shower event volume frequency distribution
........................................................................................................................................... 195
Figure 8-7 Sample pre- and post- monitor retrofit shower event flow rate frequency distribution
........................................................................................................................................... 196
Figure 10-1 Factors that influence demand (White and Turner (2003) & WSAA (2008))....... 225
Figure 10-2 Rainfall and maximum temperature with bulk recorded supply for Gold Coast City
over the duration of the Gold Coast Watersaver End Use study July 2008 – June 2010 .. 231
Figure 10-3 Pre-commissioning end use water consumption data (summer 08/09) ................. 232
Figure 10-4 Post-commissioning end use water consumption data (summer 09/10)................ 234
Figure 10-5 Average hourly diurnal pattern profile: single and dual reticulated regions ......... 237
Figure 10-6 End use hourly diurnal pattern profile: single and dual reticulated regions .......... 240
Figure 11-1 Overarching mixed methods research design ........................................................ 246
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List of Acronyms
ABC Australian Broadcasting Corporation
ABS Australian Bureau of Statistics
COAG Council of Australia Governments
CSIRO Commonwealth Scientific and Industrial Research Organisation (Australia)
DNRM Department of Natural Resources and Mines (Queensland, Australia)
EPBC Environmental Protection and Biodiversity Conservation Act (Australia)
GC Gold Coast
GCCC Gold Coast City Council
GCW Gold Coast Water
GCWF Gold Coast Waterfuture
GCWSEU Gold Coast Watersaver End Use (Project)
IPCC Intergovernmental Panel on Climate Change
IUWRM Integrated urban water resource management
PC Pimpama Coomera
PCWF Pimpama Coomera Waterfuture
Pot Potable water supply
PRW Purified recycled water
QWC Queensland Water Commission
Rec Recycled water supply
RWTs Rainwater tanks
RWTP Recycled water treatment plant
SD Standard deviation
SEQ South East Queensland
UKWIR United Kingdom Water Industry Research
UN United Nations
USA United States of America
USEPA United States Environmental Protection Agency
WDM Water demand management
WELS Water Efficiency Labelling and Standards
WSAA Water Services Association Australia
WWTP Waste water treatment plant
Measurements
L litres
L/h/p/d litres per hour per person per day
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L/H/d litres per household per day
L/p/d litres per person per day
kL kilolitre
kL/a kilolitres per annum (year)
$/kL dollars per kilolitre
ML megalitres
ML/d megalitres per day
GL gigalitres
GL/y gigalitres per year
- 1 -
Chapter 1
Introduction This thesis disseminates an extensive investigation into end use water consumption and the
effective water savings attributed to water demand management and source substitution
initiatives in the case study area of the Gold Coast, Queensland, Australia. The Gold Coast is a
major urban growth area of South East Queensland, located at the most south eastern corner of
the state, bordering New South Wales. The Gold Coast is projected to grow from the current 0.5
to 2.5 million people by 2056 (Po et al., 2003). The primary purpose of this research is the
establishment of end use water consumption data for single detached households in both
traditional single reticulated and non-traditional dual reticulated regions on the Gold Coast.
Other key purposes include: the quantification of actual end use potable water savings attributed
to dual reticulated recycled water supply schemes, determining the influence of water demand
management initiatives including educational messages and water efficient devices, and
evaluating the influence of socio-demographics and attitudes on residential end use water
consumption behaviours. This chapter provides an introduction to the research through a brief
description of the research background, the objectives of the study, the scope of the research and
an overview of the research method and design. The chapter concludes by providing detail on
the layout and structure of the thesis. Introductory background information pertinent to the
research is described in the following section.
1.1 Research Background
Water, like energy, is neither created nor destroyed but simply converted from one form to
another (Bouwer, 2000). Of the earth’s water, 97% is stored as salt water in the oceans, with
only 1% of the worlds global water occurring as liquid freshwater with the other two-thirds
captured as snow and ice (Bouwer, 2003). Of this available 1% liquid freshwater, 2% is
accessible in lakes and streams with the remaining 98% stored as ground water. Liquid
freshwater is thus an extremely finite and limited resource which needs to be managed
appropriately (Bouwer, 2000). Securing a reliable supply of fresh water for the world’s ever
increasing population is one of the biggest challenges facing society today. The United Nations
(UN) estimates that by 2025, two-thirds of the world’s population will face water shortages
(Barlow, 2009; UN, 2009).
The Intergovernmental Panel on Climate Change (IPCC) state that ‘observational records and
climate projections provide abundant evidence that freshwater resources are vulnerable and
have the potential to be strongly impacted by climate change, with wide-ranging consequences
Domestic End Use Investigation: WDM and Dual Reticulation, R.M. Willis (2010)
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for human societies and ecosystems’ (Bates et al., 2008, pp. 3). The Water Services Association
of Australia (WSAA, 2009a) states that relying on rainfall is a high risk strategy in an era of
climate change and that Australia’s frequent water scarcity occurrences has prompted residents
to see climate change as a ‘here and now’ issue rather than one of the future (WSAA, 2009a).
With such limited worldwide liquid freshwater, increasing urban water source pollution and a
growing populations steadily increasing demand on finite water sources, sustainable integrated
water planning and management has become pertinent to ensure the secure supply of freshwater
for the world’s future inhabitants. The described pressures on water supplies have instigated a
shift in urban planning towards integrated urban water resource management (IUWRM), which
sees the planning and application of a range of supply, demand and source substitution
initiatives to meet the urban water demands of the future.
The application of IUWRM initiatives has taken place readily throughout Australia with
detailed planning and implementation occurring in the research region of the Gold Coast. More
than a quarter of Gold Coast’s 2056 forecasted water demand will be supplemented by source
substitution or water demand management (WDM) initiatives. With the residential population
projected to increase from the current 0.5 million people to 2.5 million people in this time
frame, the water demand predicted to be reduced through water conservation, pressure and
leakage management, rainwater tanks and recycled water equates to 130 mega litres per day
(ML/d) (GCW & GCCC, 2007). To ensure volumetric savings are feasible, knowledge and data
on the effective potable water savings attributed to the individual WDM initiatives and source
substitution measures is necessary. Thus, an understanding of local residential consumption
behaviours and attitudes is essential. It is well documented that the monitoring and evaluation of
the effectiveness of IUWRM initiatives have been limited (White and Turner, 2003). Some
effort has been made to determine the saving attributed to WDM initiatives but this is generally
based on bulk recorded data, estimations or modelling. Only one Australian example of end use
monitoring of water efficient devices was reported in 2005, but the continued technological
developments in efficiencies of water use devices call for further research on this topic.
The relationship between attitudes and actual end use water consumption behaviour is another
area which requires significantly more investigation. Loh and Coghlan (2003) and the CSIRO
(2002) detailed how environmental attitudes affected outdoor water consumption but there is
currently no literature reporting the relationship between environmental and water conservation
attitudes on internal end use water consumption. Less precise bulk recorded water consumption
data has been linked with attitudes but researchers were not able to stipulate which water use
activities are actually influenced by attitudes (Nancarrow et al., 1996; Hassell and Cary, 2007).
The need to undertake monitoring, evaluation and review of WDM initiatives at an end use level
was stated by Giurco (2008a), Turner et al. (2005) and WSAA (2003). The need to undertake
Chapter 1: Introduction
- 3 -
location specific end use studies is also strongly encouraged to provide an understanding of
local consumption behaviours (Mayer and DeOreo, 1999; White and Fane, 2001; Turner et al.,
2005). To date, no statistically significant end use study has been carried out within Queensland.
Measurement of WDM and source substitution at an end use level requires the application of
advanced water monitoring technologies such as high resolution water meters, data loggers and
analysis programs. Monitoring end use water consumption involves recording individual usage
within households, which includes showers, clothes washing, taps, toilets, irrigation,
dishwashing and leaks. Understanding where, when and how water is being consumed assists in
the refinement and justification of WDM and source substitution initiatives.
The application of WDM initiatives is imperative in order to reduce demand and instil
sustainable water consumption behaviours in growing populations but, this is not a stand-alone
solution for the management of urban water. Additional and alternative sources are required to
augment and offset current supply sources like dams and desalination. The introduction of
recycled water to urban areas through dual reticulation is encouraged and is stated to be an
effective method of source substitution (COAG, 2009). To date, six dual reticulated urban
developments have been planned with several currently supplying residents throughout
Australia with recycled water. On the Gold Coast, residents and businesses in the Pimpama
Coomera region are now supplied recycled water through a centralised distribution dual
reticulation scheme. Measurement of potable water savings and recycled water consumption has
been calculated at the bulk supply level for many of the operating dual reticulation schemes. In
both Australian and worldwide literature, there is no evidence of an investigation on the end use
water consumption occurring within a dual reticulated recycled water region hence, the need to
undertake this study. Beyond this lack of a dual reticulation end use study, there exists a range
of significant gaps in the current body of knowledge addressing urban water resource
management. These include: a statistically significant end use water consumption investigation
for Queensland, description on the effective end use savings attributed to household stock
efficiency and educational devices and the relationship between water conservation and
environmental attitudes on end use consumption. Further discussions on current gaps in the
body of knowledge are presented in Chapter 2 and within Chapters 5 to 10. The following short
summary highlighting research gaps sets the scene for the research objectives and scope of this
study.
1.2 Research Objectives and Scope
The herein described research was conducted to provide data and knowledge to address the
above mentioned research gaps. The principle objectives of this research were: (1) to investigate
end use water consumption breakdowns and diurnal consumption patterns in detached
Domestic End Use Investigation: WDM and Dual Reticulation, R.M. Willis (2010)
- 4 -
residential households; (2) to determine the potable water savings attributed to water demand
management initiatives and dual reticulated recycled water schemes and; (3) to assess the
relationship between consumer attitudes and end use consumption. More specifically, it aimed
to establish residential water end uses in both traditional single reticulated households and non-
traditional dual reticulated households and to ascertain diurnal patterns for both of these supply
types in the context of the northern growth corridor of the Gold Coast, Australia.
The research was conducted within the following scope:
The study was limited to the context of the Gold Coast, Queensland, Australia;
The research was restricted to the end use analysis of the residential sector only (i.e. does
not include the commercial or industrial sector); and
The research focused on household water consumption in only single detached residences
(i.e. no multi-unit developments, cluster housing or attached housing, etc.).
1.3 Research Method Overview
This interdisciplinary study required a research design adapting methods from the experimental,
social science and natural science fields. An explanatory mixed methods research approach was
adopted due to the extensive range of research objectives and required data sources. The mixed
methods design integrates both quantitative and qualitative research methods, which strengthens
the research design to satisfy the defined objectives (Creswell and Plano Clark, 2007; Creswell,
2008). The explanatory mixed methods approach places emphasis on the quantitative data and
results with qualitative data used to help build or explain the initial quantitative results (Morse,
1991; Creswell and Plano Clark, 2007). There were three main phases to the research method,
which included a knowledge acquisition phase, a water end use and demand management phase
and a dual reticulated recycled water phase. Each of these phases includes numerous research
stages that contained unique methods and design. Each key phase and associated stages of the
research method are presented in Figure 1-1.
Chapter 1: Introduction
- 5 -
Phase 1: Knowledge Acquisition
Phase 2: Water End Use & Demand Management
Phase 3: Dual Reticulated Recycled Water
Stage 1a: Literature Review
Stage 1b: Set Research Objectives
Stage 1c: Research Method
Stage 2b: Obtain consenting sample
Stage 2c: Potable end use water consumption data
Stage 2d: Stock survey and water use behaviour audit
Stage 2e: Potable end use water consumption
Stage 2f: Questionnaire development, distribution and analysis
Stage 2g: Shower monitor investigation
Stage 3a: Predictive dual reticulated recycled water uptake model
Stage 3b: Dual reticulated recycled end use water consumption data collection and analysis
Stage 3c: Dual reticulated recycled water end use consumption
Stage 2a: End use water consumption design
PHASE STAGEOUTPUT/REFEREED
PUBLICATION
Chapter 1: Introduction
Chapter 2: Literature Review
Chapter 3: Research Method and Design
Chapter 5: Gold Coast Domestic Water End Use Study
Chapter 6: Revealing the impact of socio-demographics factors and efficient devices
on end use water consumption: case of Gold Coast, Australia
Chapter 7: Quantifying the influence of environmental and water conservation attitudes on household end use water
consumption
Chapter 8: Alarming visual display monitors affecting shower end use water
and energy conservation in Australian residential households
Chapter 9: Pimpama-Coomera dual reticulation end use study: pre-commission
baseline, context and post-commission end use prediction
Chapter 10: Domestic Dual Reticulated End Use Pimpama Coomera, Gold Coast,
Australia
Chapter 11: Conclusions, Contributions and Implication
Chapter 4:Situational Context and Descriptive Data Analysis
Pub
Pub
Pub
Pub
Pub
Pub
Pub = Referred Publication
Figure 1-1 Overarching mixed methods research design
The vast array of research methods and some of the key data collection phases required to meet
the objectives of this research are demonstrated by Figure 1-1. Some of the predominant
methods include end use analysis techniques, participant recruitment, stock surveys,
questionnaire surveys, experimental designs and the prediction of recycled water end use. The
overarching method and design for the research is presented in Chapter 3, while additional
details on specific research methods are discussed in relevant chapters, which represent re-
Domestic End Use Investigation: WDM and Dual Reticulation, R.M. Willis (2010)
- 6 -
formatted peer reviewed journal papers. A summary description for the key research phases are
presented below.
1.3.1 Knowledge acquisition
Published literature addressing all topics relevant to water consumption, IUWRM, demand
management, source substitution, end use studies and dual reticulated precincts was critically
reviewed to develop the required background knowledge and to formulate research objectives.
The result was the development of a subsequent two phased investigation to evaluate the
primary topics; namely, evaluating the influence of demand management initiatives on end use
water consumption and revealing the end use water consumption in a dual reticulation scheme
(i.e. end uses of potable and recycled water supplies). Details of the methods undertaken in each
phase are presented.
1.3.2 End use baseline and water demand management
The purpose of Phase 2 of the research method and design was to develop the measurement
techniques to obtain end use water consumption data and to undertake statistical and
experimental analyses to determine the water savings attributed to various water demand
management initiatives. Primarily, this phase included: establishing an understanding of
residential end use study design; determining appropriate technology for end use data collection;
verifying the sample size, research region and recruitment approach; determining the end use
consumption monitoring process and acquisition of data; developing water stock audits and
interview questions and undertaking these with each participant in the study to validate stock
and end use water consumption behaviour in households; undertaking analysis of end use water
consumption data; development, application and analysis of a questionnaire survey to establish
socio-demographics and attitudinal perceptions surrounding water related issues; and, the
recruitment, delivery and analysis of an experimental water demand management educational
shower monitor for a sub-sample of the research participants. This phase also involved the
establishment of the link between environmental and water conservation attitudes on end use
water consumption. The application of these methods resulted in the development of four
journal papers, which have been published or are currently under peer review (Chapters 5 to 8).
1.3.3 Dual reticulated recycled water
Phase 3 involved the adoption of methods and analysis techniques to investigate the potable end
use water consumption savings attributed to the supply of recycled water to dual reticulated
residential households in the Pimpama Coomera (PC) region. This phase of the research method
was implemented to develop a predictive uptake model and to subsequently measure the end use
water consumption occurring in a dual reticulated recycled water region. Primarily, this phase
Chapter 1: Introduction
- 7 -
included: the development, application and verification of a predictive recycled water uptake
model, pre-commissioning of recycled water to the PC region; measuring end use water
consumption in the PC region post-commissioning of recycled water; validating end use water
consumption in the PC region for both recycled and potable water; and developing a tool to
ascertain diurnal consumption patterns for dual and single reticulated regions. The application
of these methods resulted in the development of two journal papers either published or
submitted for peer review (i.e. Chapters 9 to 10).
1.4 Thesis Layout
This research is presented through a refined layout that includes both traditional thesis chapters
and reformatted peer reviewed publication chapters. This has resulted in a strengthened ‘thesis
by publication’ approach due to the distinctive academic and practical elements of the thesis.
The ‘thesis by publication’ layout differs from a traditional thesis by the inclusion of published
peer reviewed papers in place of traditional data analysis, results and discussion chapters.
However, traditional introductory chapters are included in order to outline the research
approach, methods and context of the study. Such chapters include the herein described
introduction, literature review, research method and design, and situational context and
descriptive data analysis. Published, accepted or submitted peer reviewed journal publications
make up the remainder of the chapters. The chapters that contain reformatted peer reviewed
papers each include a literature review, methodology, results and discussion specific to stated
research objectives and topic. The final chapter summarises overall research conclusions,
recommendations, contributions, implications, limitations and future research directions.
Readers should note that the literature review, research method and design, and situational
context and descriptive data analysis chapters all present overarching details of the entire
research project. However, each results chapter, represented by peer reviewed journal
manuscripts, also includes background information, a targeted literature review, and detailed
descriptions of methodologies and data analysis techniques applied.
There are two distinct components or phases of peer reviewed publications within this thesis
being:
1. The establishment of baseline end use water consumption in the Gold Coast and
investigations into the effect of water demand management initiatives including
efficient and consumption awareness prompt devices as well as establishing the
relationship between attitudes and end use water consumption behaviours; and
Domestic End Use Investigation: WDM and Dual Reticulation, R.M. Willis (2010)
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2. Predicting, investigating and reporting the end use water consumption and diurnal
patterns within a dual reticulated recycled water development region (i.e. Pimpama
Coomera).
In its entirety, the thesis consists of eleven chapters. This chapter introduces the research
through discussion on the research motivation and background, presented a summarised
overview of the research method and discussed the ‘thesis by publications’ layout of this study.
More importantly, the chapter presents the broad research objectives for the study which were
developed from the knowledge acquired through the literature review and established research
gaps. The research objectives directed the design of the research method and underpinned
investigations for the acquisition of results to meet the objectives.
Chapter 2 provides a detailed discussion and review of all literature relevant to water
consumption, integrated urban water management, water demand management, source
substitution, advanced water consumption monitoring technologies, end use studies and dual
reticulated recycled water schemes. Moreover, the chapter explores earlier research covering
fields of particular interest being water efficient devices, educational devices, attitudes and the
impact this has on behaviour, monitoring of dual reticulated recycled water and the variability in
results from worldwide end use studies. The chapter concludes through a research persuasion,
which summarises the reviewed literature and presents the key gaps that currently exist in the
body of knowledge. Additional critical reviews of literature are detailed within Chapters 5 to 10.
Chapter 3 details the research method and design, which stipulates the key theories relevant to
the research approach and discusses the analytical techniques adopted in this study. Initially,
this chapter presents the overarching methodological approach utilised to carryout the research
and then proceeds to detail each particular phase and stage of the method. Additional
discussions on key analytical techniques and methods specific to various papers within the
thesis are presented in Chapters 5 to 10. Chapter 3 is focused on presenting the core research
method and design.
The situational context and descriptive data of the research sample are detailed in Chapter 4.
This chapter describes the context within which the research was carried out, presents rainfall
and climatic data experienced over the research period and lists bulk water consumption data.
Furthermore, this chapter provides a detailed discussion on the characteristics of the recruited
research sample. Data from each of the end use data recording periods are also detailed. Hence,
Chapter 4 presents any details, which were considered influential on the results of this study and
provides a descriptive overview of the research sample and end use water consumption results.
Chapter 1: Introduction
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Chapter 5 is the first of the published peer reviewed paper chapters. This chapter presents the
preliminary findings from the research, aptly named the Gold Coast Watersaver End Use
(GCWSEU) study. The paper describes the purpose of the study, outlines some initial objectives
of the research program and specifies the timeline to undertake this research. The paper also
details end use data from winter 2008, compares findings with other national end use studies
and explores two highly variable end use distributions, namely shower and irrigation. This
chapter concludes by discussing the ongoing research program for the GCWSEU study.
Chapter 6 presents detailed data and discussion on the impact of socio-demographic factors such
as income, education status, family groups and socioeconomic regions, on end use water
consumption. Analysis on the effective end use water savings attributed to efficient devices is
presented. Examination on the payback period for the analysed water efficient devices was also
detailed. Chapter 6 concludes with discussion on the implications for water planning and urban
water demand forecasting.
Chapter 7 explores the relationship between environmental and water conservation attitudes and
end use water consumption behaviours. Initially, the chapter details the theory and development
of environmental and water conservation attitudinal factors from the literature. Socio-
demographic characteristics of the groups are also detailed. Detailed statistical analysis is then
described, which includes confirmatory factor analysis and cluster analysis. The paper presents
the determination of two distinct attitudinal groups being very high concern (VHC) and
moderately high concern (MHC) for both environmental and water conservation practices.
Results on the statistically significant relationship found between discretionary end use water
consumption and lower water consumption by the VHC group and higher water consumption by
the MHC group are presented. The results underpin the need for sustainable water conservation
attitudes to be instilled prior to implementing any water demand management measures.
Chapter 8 details an experimental investigation examining the performance of an alarming
visual display device on shower end uses. This paper presents the initial end use water
consumption found for showering and then details the experiment, which involved the
installation of an alarming shower monitor to reveal the effect on end use shower water
consumption. The paper details the significant volumetric savings attributed to the installation
of the shower device and also explores its effect on the duration and flow rate of showers. The
payback period, based on monetary water and energy savings related to the installation of the
device, is also presented.
Chapter 9 presents the first paper related to the measurement of the dual reticulated recycled
water scheme in Pimpama Coomera (PC), aptly named the Pimpama Coomera Dual
Domestic End Use Investigation: WDM and Dual Reticulation, R.M. Willis (2010)
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Reticulation End Use Study. This chapter details the pre-commissioning baseline recycled water
consumption in the PC region and presents the development of a model which includes factors
reported to influence recycled water uptake from the literature. The model then predicts the
post-commissioning recycled water consumption for the PC region. The chapter concludes with
an overview of the additional research stages to be undertaken to measure actual post-
commissioning recycled water end use.
Chapter 10 presents the results from monitoring recycled water end use consumption post-
commissioning in the PC region. The chapter presents data from several logging periods along
with diurnal pattern consumption rates for recycled and potable water at an end use level. This
paper also compares actual end use consumption with the consumption values formulated by the
developed prediction model and the Pimpama Coomera Waterfuture (PCWF) Master Plan
predictions.
Finally, Chapter 11 summarises the key research outcomes, disseminates the contributions made
by the research to the existing body of knowledge and presents implications of results for the
water management field. The chapter also presents recommendations for implementation in the
water industry and the need for future research in this field and addresses any limitations of the
research. Supplementary information in the form of appendices are provided at the conclusion
of Chapter 11.
1.5 References
Barlow, M. (2009) Notes for Opening Keynote Australian Water Summit, 1 April 2009. Australian Water Summit.
Bates, B. C., Kundzewicz, Z. W., Wu, S. & Palutikof, J. P. (2008) Climate Change and Water - IPCC Technical Paper VI. Intergovernmental Panel of Climate Change (IPCC) Secretariat, Geneva.
Bouwer, H. (2000) Integrated water management: emerging issues and challenges. Agricultural Water Management, Vol 45:3, pp. 217-228.
Bouwer, H. (2003) Integrated water management for the 21st century: Problems and Solutions. Food, Agriculture & Environment, Vol 1:1, pp. 118-127.
Council of Australian Governments (COAG) (2009) Intergovernmental Agreement on a National Water Initiative. Canberra. Online article, accessed 23/03/09, available at: http://www.coag.gov.au/coag_meeting_outcomes/2004-06-25/index.cfm.
Creswell, J. W. (2008) Educational Research: planning, conducting, and evaluating quantitative and qualitative research, 3rd ed, New Jersey, Pearson Education, Inc.
Creswell, J. W. & Plano Clark (2007) Designing and conducting mixed methods research, USA, Sage Publications, Inc.
Chapter 1: Introduction
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CSIRO (2002) Perth domestic water-use study household ownership and community attitudinal analysis. NSW, Australian Research Centre for Water in Society CSIRO Land and Water
Giurco, D., Carrard, N., McFallan, S., Nalbantoglu, M., Inman, M., Thornton, N. & White, S. (2008) Residential end-use measurement guidebook: a guide to study design, sampling and technology. Prepared by the Institute for Sustainable Futures, UTS and CSIRO for the Smart Water Fund, Victoria.
Loh, M. & Coghlan, P. (2003) Domestic Water Use Study. Perth, Water Corporation.
Mayer, P. W. & DeOreo, W. B. (1999) Residential End Uses of Water. Denver, CO, Aquacraft, Inc. Water Engineering and Management.
Morse, J. M. (1991) Approaches to qualitative - quantitative methodological triangulation. Nursing Research, 40, 120-123.
Turner, A., White, S., Beatty, K. & Gregory, A. (2005) Results of the largest residential demand management program in Australia. Institute for Sustainable Futures, University of Technology. Sydney Water Corporation, Sydney, NSW
UN (2009) Majority of world population face water shortages unless action taken, warns Migiro. UN News Centre. Online multimedia, available at: http://www.un.org/apps/news/story.asp?NewsID=29796&Cr=water&Cr1=agriculture. New York, USA.
White, S. & Fane, S. (2001) Designing cost effective water demand management programs in Australia. Water Science and Technology, Vol. 46:6-7, pp. 225-232.
White, S. & Turner, A. (2003) The role of effluent reuse in sustainable urban water systems: untapped opportunities. National Water Recycling in Australia Conference. Brisbane, September 2003.
WSAA (2003) Urban Water Demand Forecasting and Demand Management: research needs review and recommendations. White, S. Robertson, J. Cordell, D. Jha, M. Milne, G. Institute for Sustainable Futures UTS for Water Services Association, Sydney.
WSAA (2009) Media Release (August 19, 2009) Australia the world leader in urban water efficiency. Water Services Association of Australia. Online article, available at: https://www.wsaa.asn.au/Media/Press%20Releases/20090820%20News%20Release%20-%20Report%20Card.pdf.
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Chapter 2
Literature Review This chapter presents background information and a review of literature pertinent to the
research. The topic is introduced through an overview of the water crisis and details of urban
water consumption with particular reference to the study region of the Gold Coast. A
description of integrated urban water resource management (IUWRM) is outlined along with
Gold Coast city’s example of this water management principle. Elements of IUWRM including
supply and demand management and source substitution are all presented. A thorough overview
of earlier research on water demand management and source substitution is presented to
determine prior research investigations of the effective water savings of these initiatives. A
summary of advanced water consumption monitoring technologies, earlier end use water
consumption studies and dual reticulated precincts is presented. The chapter concludes by
outlining current gaps in the body of knowledge and detailing the research approach for this
study. An overview of literature examined in this chapter is presented in Figure 2-1.
Figure 2-1 Overview of reviewed literature topics
Figure 2-1 demonstrates the structure of the literature review as detailed in this chapter.
Demand, supply and source substitution all stem from the IUWRM. There are several elements
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under each topic with blue shaded boxes indicating the topics focused on for this investigation.
The grey shaded boxes indicate the sub-topics which have been explored in significant detail. It
should be noted that more critical reviews of literature are presented in each of the peer
reviewed papers that form the subsequent chapters of the thesis. Background information and
reviewed literature are discussed.
2.1 The Water Conditions in Australia
Australia is the world’s driest inhabited continent with the most unpredictable rainfall patterns,
hence it is important to conserve the nations already finite water supply (Birrell et al., 2005;
Commonwealth of Australia, 2008c). The Intergovernmental Panel on Climate Change (IPCC)
state that ‘observational records and climate projections provide abundant evidence that
freshwater resources are vulnerable and have the potential to be strongly impacted by climate
change, with wide-ranging consequences for human societies and ecosystems’ (Bates et al.,
2008, pp. 3). There is mounting evidence that anthropogenic caused global climate change is
increasingly affecting weather patterns (Bates et al., 2008; CSIRO, 2010). This is predicted to
result in the alteration of river runoff and water availability and cause increased precipitation
variability and intensity (CSIRO, 2007). Such changes will trigger more extreme drought and
flood conditions, decrease water supply in glaciers and snow cover, increase water pollution due
to the extreme drought and flood conditions, instigate sea level rise and alter water quantity and
quality (Pittock, 2006; CSIRO, 2007; Solomon et al., 2007; Bates et al., 2008; Allison et al.,
2009).
Studies by the Australian Bureau of Meteorology suggest that since 1910, Queensland has
become increasingly hotter and drier (Commonwealth of Australia, 2010). The southern half of
Australia is also experiencing trends of reduced rainfall by up to 50 mm annually (Anderson,
1996; CSIRO, 2010). This reduced rainfall trend is occurring over concentrated urban centres
where most of the nation’s population resides. Reduced rainfall has resulted in many southern
cities and towns rainfall dependant water supplies falling to record low levels (Commonwealth
of Australia, 2008a; ABS, 2010). South East Queensland (SEQ) recently experienced the worst
recorded drought period for both length and rainfall deficiency. This drought period was known
as the ‘Millennium drought’ extended from 2001 to 2009, finally breaking in May 2009 when
significant rainfall occurred and the combined dam water storages reached 60% (QWC, 2009).
Trends and incidence of reduced rainfall and extended drought periods have resulted in the
management of water resources being a major concern for water authorities, public and private
industries and all levels of government in Australia (Inman and Jeffrey, 2006). Traditionally, the
supply of water for cities and towns placed a heavy reliance on dams, weirs or rivers but
Chapter 2: Literature Review
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changing weather patterns, increasing urban demands and detrimental impacts to freshwater
sources from urban discharges have triggered a need to move beyond such traditional source
options (Barlow, 2009). Hence, the approach is now focused on planning and adopting new
ways to manage water to meet the short-term water supply deficiencies and aid in meeting long-
term demand (Turner et al., 2005; Webb, 2007; Barlow, 2009). A common conclusion from
recent investigations and reviews of urban water supply and demand forecasts is that Australia
must invest in adequate planning now, to ensure a secure and sustainable water supply for future
generations.
2.2 Water Consumption and Demand Forecasting in Urban Australia
Australians are some of the highest water consumers in the world despite the nations well
documented low average rainfall (CSIRO, 2006). Table 2-1 details Australia’s national water
consumption in 2004-05 being 18,767 gigalitres (GL), which was a drop of 14% from 2000/01
consumption levels. Although water consumption in Australia is primarily dominated by
agricultural use, the data presented in Table 2-1 demonstrate that households and the supply of
water for urban consumption accounts for 22% of Australia’s total water consumption or 4191
GL annually (highlighted in grey).
Table 2-1 Australia’s water consumption by sector 2004-05 (ABS, 2007)
2000-01 Volume
(GL)
% of total 2004-05
Volume (GL)
% of total
Agriculture 14,989 69.1 21,191 56.0
Household 2,278 10.5 2,108 11.2
Water Supply 2,165 10.0 2,083 11.1
Other industries 1,102 5.1 1,059 5.6
Manufacturing 549 2.5 589 3.1
Mining 321 1.5 413 2.2
Electricity and gas 255 1.2 271 1.4
Forestry and fishing 44 0.2 51 0.3
Total 21,703 100 18,765 100
Urban household water supply accounts for 22% of the nations water consumption (see Table
2-1), however, in individual urban cities and towns, residential households consume between
60-70% of the total bulk water supplied (WSAA, 2009b). In Queensland on the Gold Coast, a
city with a population of 0.5 million people, residents consume 75% (08/09) of the cities total
yearly water supply (GCW, 2009a). A study by Birrell et al. (2005), which investigated the
impact of demographic change and urban consolidation on domestic water use in Australian
cities indicates that between the years 2001 to 2031, water demand in major cities will increase
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by 37%. Moreover, Australia’s population is estimated to rise from 22 million in 2009 to 34
million in 2050, a growth rate of 2.1%, with most of this growth experienced in urban cities
(Birrell et al., 2005). Such extensive residential growth and the increasing demand of water has
triggered the focus on understanding, predicting, forecasting, measuring and validating urban
water consumption.
Determining the water demand of a city requires consideration of water services historical
records, system performance and projected changes in demand patterns (DNRM, 2005). Factors
considered for water demand predictions include potable, waste and recycled water average
demand at source, level of treatment required and the level of distribution (DNRM, 2005).
Water demand modelling elements include peaking factors (maximum day, mean day maximum
month and maximum hour), diurnal patterns, end use water consumption, fire fighting
parameters, pressure parameters, system losses and non-revenue water (WSAA, 2003). Some of
the factors which influence urban water demand forecasting and need to be considered, are
demonstrated in Figure 2-2.
Water supply system
DEMAND FORECASTING Factors influencing peak
period and/or average bulk water demand
Demographics & land use
Water using equipment
Source Substitution
Water usage practices
Climate
WeatherTourism
Occupancy rate
Population
Residential lot size
Housing type, mix & age
Losses
Pressure
Other unaccounted
flow/non-revenue water
Equipment & appliance stock &
sales
Climate change
Income + Soci-cultural factorsWater/wastewater Pricing • Technical innovation •
Restrictions • Knowledge & awareness • Regulation
Rainwater tank
Greywater
Effluent reuse
Industrial reuse
evaporation
rainfall
Max day temp
Figure 2-2 Factors that influence demand (White and Turner, 2003; WSAA, 2008)
All of the forecast parameters displayed in Figure 2-2, are relevant for the accurate forecasting
of urban demand, especially residential, but all too often ‘demand forecasting studies have
relied on projections of historical metered data without considering end uses’ or by adopting end
use data from different locations or countries (WSAA, 2003, pp. 6). Because household water
consumption differs between countries, locations and populations, it is paramount that location
specific end use data is utilised for local demand forecasting (Turner et al., 2005; Inman and
Jeffrey, 2006). This is due to the location-specific variations in climate, tourism, residential
Chapter 2: Literature Review
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characteristics, stock, education, lot size, income, attitudes and behaviours of consumers all
impacting water demand (Nieswaidomy and Molina, 1989; Renwick and Archibald, 1998;
Mayer and DeOreo, 1999; Renwick and Green, 2000; WSAA, 2003; Inman and Jeffrey, 2006).
Thus, with all of these elements influencing local water demand, there is a growing requirement
for accurate data, at an end use level (Giurco et al., 2008a). The mounting demand on
Australia’s scarce water supplies, due to population increase, has also triggered the need for
determining local residential water consumption behaviours and demand to accurately forecast
future water requirements.
Forecasting and planning to ensure a secure supply of water for future urban populations
requires the integration and adoption of supply-side, demand-side and source substitution
measures, as demonstrated in Figure 2-2 (White and Turner, 2003; Bates et al., 2008). CSIRO
scientists state that ‘measures designed to help communities to cope with reduced water supply,
such as water conservation and recycling are necessary and indeed urgent’ (Pittock, 2006, pp 1).
Growing demand, diminishing supply, population growth, rainfall variability, issues of water
source pollution and the need to ensure continued releases of water for environmental flows for
the protection of surviving downstream ecosystems, have influenced thinking towards an
integrated urban water resource management approach (Turner et al., 2007a). This encompasses
a multitude of supply, demand and source substitution solutions to manage the increasing
pressure for the provision of a secure source of water.
2.3 Gold Coast City’s Solution to the Water Crisis
The Gold Coast is one of SEQs major urban growth regions with population projected to grow
from the current 0.5 million people to approximately 2.5 million in 2056. This equates to an
equivalent water demand increase from 185 mega litres per day (ML/d) to 466 ML/d by 2056
(GCW & GCCC, 2007). With such significant increases in population and water demand, the
water management authority for Gold Coast city, Gold Coast Water (GCW), has planned for
their water future using IUWRM principles.
The Gold Coast Waterfuture (GCWF) Master Plan was developed as the long term IUWRM
strategy to meet the projected urban water requirement of 466 ML/d for 2056. The GCWF
Master Plan incorporates a cohort of supply, demand and recycling initiatives to ensure the
projected water demand is satisfied. A graphical overview of the GCWF water balance is
presented in Figure 2-3 .
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Figure 2-3 Gold Coast Waterfuture Master Plan water balance 2007 (GCW & GCCC, 2007)
Each of the IUWRM initiatives in the GCWF Master Plan (Figure 2-3 is demonstrated in Table
2-2. Additionally, the water demand that each initiative satisfies along with alternative supplies
considered to meet Gold Coast’s 2056 water requirements are outlined (Table 1-3).
Table 2-2 Gold Coast Waterfuture Water Balance (GCW & GCCC, 2007)
Initiatives Water Balance 2007 Current Strategy
(ML/d)
Percentage of total demand (%)
Existing Supply Hinze Dam and Little Nerang Dam 191 41%
Desalination 111 24%
Pressure and leakage management 30 6.5%
Rainwater tanks 20 4%
Raising of Hinze Dam including water harvesting
34 7%
Recycled water 30 6.5%
Key Initiatives
Water conservation 50 11%
Greywater Local use
Ground water Local use
Indirect potable reuse Under investigation
Local and Emerging Initiatives
Stormwater harvesting Local use
Total water needs in 2056 466 100%
The existing supply measures, before 2007, were the Hinze and Little Nerang Dams, new
supply measures included raising the Hinze Dam and desalination (desalination plant at Tugun
was operational from March 2009) (Table 1-3). Demand management initiatives of the GCWF
Master Plan include pressure and leakage management and water conservation measures such as
water efficient devices, restrictions and education of consumers. The planned source
Chapter 2: Literature Review
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substitution options include recycled water and rainwater augmentation to satisfy the projected
2056 water requirements. Table 2-2 demonstrates the supply sources that will satisfy 65% of the
city’s total water demand, while the remaining 35% will be satisfied through demand
management initiatives and source substitution measures. Measuring and monitoring the supply
of bulk water is relatively easy, while measuring the effectiveness of water demand
management and source substitution initiatives to ensure they satisfy the 35% reduction in
demand is not as simple. Carrying out this evaluation process is significantly more challenging
than measuring and monitoring bulk supply but is imperative to ensure that these estimated
demand reductions and source substitution targets are actually achievable (White and Turner,
2003).
2.4 Integrated Urban Water Resource Management
Traditionally, urban water utilities made decisions based primarily on finance and engineering,
but in the last decade, significant consideration has been placed on incorporating sustainability
principles into the process (Mitchell, 2006; WSAA, 2009c). The IUWRM process involves the
planning and integration of supply, demand and source substitution options for the sustainable,
secure and reliable supply of water to meet projected future water demands of cities or towns
(White, 2001; Inman and Jeffrey, 2006; Mitchell, 2006). The combination of socio-behavioural
and technological strategies to promote water conservation is the focus (Corral-Verdugo et al.,
2002). Some of the benefits of IUWRM include (Butler and Maksimovic, 1999; White and
Turner, 2003; Mitchell, 2006):
A reduction in potable demand;
Reductions in wastewater discharges;
Reduced stormwater flows;
Lower peak flows and flood damage;
Enhanced water efficiency;
Increased variation and diversification of supply sources through the introduction of
recycled, rain, grey or stormwater;
Improvement in stormwater quality (load and concentration); and
The incorporation of green infrastructure such as wetlands for wastewater treatment.
A framework for the planning and implementation of IUWRM is detailed in Figure 2-4. These
steps include the need to: calculate the demand-supply balance; determine options for supply,
demand and source substitution; implement these initiatives; and finally to monitor, evaluate
and review the effectiveness of implemented measures. Australian water entities have actively
planned and incorporated IUWRM principles for long term water security and have been
Domestic End Use Investigation: WDM and Dual Reticulation, R.M. Willis (2010)
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recognised around the world as leaders especially in water efficiency and climate change
adaptation (WSAA, 2009c).
Significant progress in IUWRM in Australia has been made by Sydney Water Corporation, The
Water Corporation in Western Australia, Gold Coast Water (GCW), Melbourne Water and
Yarra Valley Water (WSAA, 2008). Turner and White (2006) suggest that while substantial
effort is placed on the first four steps of the IUWRM framework (see Figure 2-4) that often the
final step of monitoring, evaluating and review is not adequately undertaken. This final step
feeds necessary data and information back into the demand forecasting and options models to
assess how individual programs are contributing to the overall demand management target or
the supply-demand gap (Turner and White, 2006). White and Turner (2006) specify that
monitoring and evaluation should be undertaken on individual programs to alleviate the risk of
over estimating the actual savings achieved by the programs. This is paramount for accurate
planning. The following sections present details on supply solutions, demand management and
source substitution initiatives that embody the principles of IUWRM.
2.4.1 Supply sources
Supply solutions for IUWRM place a heavy reliance on dams, with new dams being
constructed, dam walls lifted and additional weirs added to increase original storage capacities.
A study by Turner et al. (2007a) of SEQs water supply and demand options revealed that one of
the proposed supply sources, the Mary River Traveston Crossing Dam, was not actually
required to meet projected water demand in the region. The dam was rejected in 2009 under the
Australian Environmental Protection and Biodiversity Conservation (EPBC) Act 1999 due to
the environmental threat and damage posed to endangered species like the Mary River turtle and
the Australian lungfish (ABC, 2009). While dams still play an very important part in the supply
of water for Australia, the extensive community protest against dams, as seen for the Traveston
Crossing dam, and the obvious detrimental impact to existing natural and built environments
from dam projects make them a less desirable supply option. Hence there is an increased focus
on other alternatives such as desalination, water recycling and raising walls on existing dams.
Chapter 2: Literature Review
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Figure 2-4 Australian IUWRM framework (Turner and White, 2006)
Desalination of sea water for potable consumption has become a favoured and climate-
independent supply-side initative (Barron, 2006). Desalination is gaining popularity because it
is neither rainfall or climate-dependent. Queenslands first major desalination plant was built at
Tugun on the Gold Coast and is capable of supplying 125 ML of water per day to SEQ (QWC,
2008a). The desalination plant in Perth has been supplying 130 ML/d or 17% of the cities water
needs since November 2006 (Water Corporation, 2010) and Sydney’s wind powered
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desalination plant, which is due for commissioning in 2010, will supply 15% of Sydney’s total
water needs (NSW Government, 2010). Increased variability of rainfall has instigated a move
towards desalination plants as a preferred supply option to meet the future water demand of
communities in SEQ and across Australia. While desalination is emerging as a preferred
measure to dams, this supply source of water does not come without negatives. Desalination is a
highly energy intensive process with the resulting water requiring mixing to ensure the taste and
salt content is not to high for consumers. Desalination plants also require continuous operation
which means that in non-drought periods this energy intensive source of water will often still be
supplied. Other issues, such as long-term potential environmental impacts from the temperature
and salt content of the brine solution (waste stream of water) disposed of in deep sea outlets and
ongoing maintenace and replacement of components also require consideration. The recycling
of waste water is another alternative supply source solution examined later in text. It is argued
that managing and reducing water demand can offset the construction of supply infrastructure
by years or decades (White, 2001; Turner et al., 2007a).
2.4.2 Demand management
Water demand management (WDM) is a key element of IUWRM, which assists in delaying the
need for new supply infrastructure (White, 2001; Anderson, 2003). It has been a significant
focus for Australia’s municipal and private water utilities, and a range of programs have been
developed to manage and reduce both residential and industrial water consumption demands
(Sarac et al., 2002; Turner et al., 2005). Aspects of WDM include pricing, legislation, metering,
conservation and education. Demand reducing initatives such as water restrictions, regulations,
water efficient devices and behavioural change programs have been introduced extensively
across Australia.
An example of a successful Gold Coast WDM program was the ‘Home WaterWise Service’,
which was first introduced in the city in 2005 and expanded across SEQ in July 2006. The
household program involved the installation of new water efficient showerheads and tap
aerators, fixing of leaking taps and information and advice on how to make a home water
efficient at a cost of just $20 to the homeowner (valued at $150) (GCW & GCCC, 2007;
Queensland Government, 2008a). The scheme concluded in 2008 and was taken up by 228,551
households or one in every six homes across SEQ. Water savings were estimated through bulk
supplied and bulk recorded water values to be 4.7 gigalitres (GL or billion litres) per annum.
A pressure and leakage reduction program was another WDM initiative introduced across all
SEQ council regions. The aim of the project was to provide water savings of 10% or 60 ML/day
through repairing leakage and reducing supply pressures in residential areas (LGIS, 2009). Such
WDM programs have been in place for several years with bulk water savings estimated and
Chapter 2: Literature Review
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reported. To date, no program specific monitoring, evaluation or review of actual savings has
been carried out, nor has there been verification of savings related to the individual demand
management initatives within the programs such shower rose replacement in the ‘Home
WaterWise Service’. As discussed, undertaking such assessment and review processes is critical
to ensure the estimated savings are achieved especially for demand forecasting predictions. The
final component of IUWRM is source substitution, details are presented in the following
section.
2.4.3 Source substitution
Anderson (2003) states that source substitution is a key element of IUWRM. Source supply
substitution involves substituting traditional potable water demand with an alternative source of
water which can be either recycled, rain, grey or storm water. Source substituted water is
generally utilised for ‘fit for use’ activities or non-potable consumption activities such as
irrigation, toilet flushing or clothes washing. An alternative source of water for residential
consumption is now legislated by Part MP 4.2 of the Queensland Development Codes 2007.
These codes stipulate that residential homes must achieve water savings of at least 5 kL or 3 kL
(depending on the dwelling type) with rainwater tanks (RWTs) suggested as the most common
means to meet these requirements (Queensland Government, 2008b). This regulation, and the
assortment of rebates offered over the past few years for the installation of RWTs for existing
dwellings, has seen 240,000 RWTs installed in SEQ as at November 2009 (Moore, 2009).
The introduction of recycled water as a substitution for potable water is occuring in various
ways. Recycled water is most commonly utilised as a ‘fit for use’ source through dual
reticulation which involves a separate pipeline supplying water for irrigation and toilet flushing
(Anderson, 2003; Council of Australian Governments, 2009). Another, indirect way of use, is
introducing recycled water into water reservoirs as purified recycled water (PRW) for treatment
and distribution through the potable supply system (Turner et al., 2007a). Although it still
remains controversial, dramatic improvement in community perceptions towards recycled water
reuse have occurred recently (Nancarrow et al., 2007). This improved perception and the need
to reduce the demand on potable supply sources have enhanced the introduction and acceptance
of recycled water as a source substitution alternative (Dimitriadis, 2006). Additional detail on
the specific elements of both water demand management and recycled water as a source
substitution alternative are presented in the following sections.
2.5 Water Demand Management
Water demand management (WDM) is defined as the practical ‘development and
implementation of strategies aimed at influencing demand to achieve efficient and sustainable
Domestic End Use Investigation: WDM and Dual Reticulation, R.M. Willis (2010)
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use of a scarce resource’ (Savenije and van der Zaag, 2002, pp. 98). Managing and reducing
demand is based on reducing everyday average water consumption to minimise the pressure on
dwindling potable water supplies or to assist in filling the gap between supply and demand
(Tate, 1993; Deverill, 2001; Brooks, 2006; Turner et al., 2007b). Indoor WDM programs have
the additional benefit of reducing the volume of water discharged into sewerage systems
(WSAA, 2009c). Application of WDM is a particually important and useful initiative in rainfall
limited areas and its application is required throughout the world to meet the goal of sustainable
water and resource consumption. WDM measures are generally the most sustainable solutions
across environmental, social and economic factors, when considering the range of options
presented for water supply security (Turner et al., 2007b; White et al., 2007). WDM measures
focus on reducing end use consumption hence, offsetting the need for additional water supply
and wastewater treatment, which can be costly and environmentally and socially detrimental.
Demand management initiatives are focused on supplying tools, mechanisms and knowledge to
enable consumers to continually reduce their potable water consumption (Turner and White,
2006). The WDM approach relies heavily on consumers to understand how to reduce their water
consumption and to apply this understanding to everyday activities. There are numerous
elements of WDM which can be classified in various ways for example technological, financial,
legislative, operation and maintenance, and educational (Inman and Jeffrey, 2006). These are
commonly referred to as restrictions, regulations, efficient devices, and educational behaviour
altering tools (White, 2001). A description on this array of WDM initatives is detailed in the
following sections some of which are not directly related to this research but are included to
give an overarching view of demand management.
2.5.1 Water metering
Water metering, a technological or engineering initiative, was the first major WDM measure to
be broadly implemented across Australia. Its introduction arose largely from the well
established maxim of ‘if you can’t measure it, you can’t manage it’ (Mitchell, 2006). Metering
water consumption and charging per unit (kilolitre) of water used, gives water a dollar value and
signifies to users that the more they consume the more they are charged (Inman and Jeffrey,
2006). Research across the world has demonstrated that reductions of up to 56% can occur after
the installation of water meters although consumption behaviour may not remain consistently
low as consumers grow accustomed to metering (Linaweaver et al., 1966; USEPA, 1998;
Maddaus, 2001; Inman and Jeffrey, 2006). Water metering of residential consumption occurs in
almost all Australian cities. Metering water consumption at the residential boundary is a well
established and effective WDM initiative which has been shown to reduce water consumption
(UKWIR, 1996; Inman and Jeffrey, 2006) hence, this was not a focus of this research.
Chapter 2: Literature Review
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2.5.2 Enforcement
Water Restrictions
Water restrictions, regulations and environmental labelling are all enforcement initiatives
applied to achieve water savings. Water restrictions are the most common WDM introduced
nationally to reduce residential water consumption due to the fact that external water use is
generally considered nonessential in times of drought (Syme et al., 2004; Brennan et al., 2007).
Australian water restrictions focus on limiting outside watering and stipulating the time of day
for watering or defining external water use fixtures allowed for use i.e. a hose or bucket
(Barrett, 2004). Recent severe drought conditions in SEQ have resulted in restrictions
stipulating the amount or volume of water used internally and externally. For example, each
person has a daily allocation of 140 to 230 litres per person per day (L/p/d). The water
restriction levels becomes more severe or restricting with dropping supply sources i.e. 60%
capacity in the dam allows for a daily allocation of 230 L/p/d while 20% capacity in the dam
results in the allocation of 140 L/p/d. Earlier research by Nancarrow et al. (2002) determined
that while residents are supportive of regular low level restrictions (i.e. watering 2 to 3 days per
week over summer) they were not supportive of permanent or severe restrictions (i.e. no
external water use or bucketing water only for long periods). Water restrictions are very
effective in reducing water consumption (Barrett, 2004) and have been in place in Australia for
decades. The effectiveness of restrictions was investigated by the United Kingdom Water
Industry Research (UKWIR, 1998) and Inman and Jeffrey (2006), with savings of up to 49%
recorded. The effectiveness of water restrictions as a potable water saving mechanism has been
well established hence this is not a focus of the research.
Regulation and Legislation
Regulating and legislating the use of new efficient water use fixtures and stipulating demand
reductions in building codes has been found to to be a very effective enforcement measure
(Barrett, 2004). The Queensland Development Code (2007) Part MP 4.1 mandates that all new
houses and townhouses (class 1 buildings) and units (class 2 buildings) must have minimum of
3-star Water Efficiency Labelling and Standards Scheme (WELS) rated toilets and showerheads
(Queensland Government, 2009). In fact, all new detached households in SEQ must meet water
saving targets of 70 kilolitres per year (kL/yr) while Class 2 dwellings must save 42 kL/yr
(Queensland Government, 2008b). Suggestions to achieve these savings include the installation
of low flow shower heads, dual flush toilets and RWTs (Queensland Government, 2007).
Research into quantifying the water savings attributed to mandatory installation of rainwater
tanks is being undertaken by Beal et al. (2010).
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Labelling The Australian Water Efficiency Labelling and Standards Act 2005 is the Australian Act which
stipulates water efficiency labelling and regulates water efficiency standards (Commonwealth of
Australia, 2005). The Australian WELS scheme was introduced under the Act in July 2006 to
register and label products with water efficiency ratings, Figure 2-5 demonstrates a label
awarded through WELS (Commonwealth of Australia, 2009).
Figure 2-5 WELS water rating label (Commonwealth of Australia, 2009)
The introduction of WELS is estimated to result in a 5% annual reduction of domestic water use
through informed consumer selection of the most appropriate and water efficient product
(Commonwealth of Australia, 2009). Exhibiting certified water consumption information on
water use devices ensures that the consumer understands the device or fixture’s consumption
when purchasing products. Monitoring the effect of national regulations and environmental
labelling would require an Australia wide investigation, hence this has not been included in the
scope of this research.
2.5.3 Water pricing
Water is one of the lowest priced resources when compared to other resources like electricity or
fuel. When pricing for water per kilolitre was first introduced in Australia, it was suggested that
it may reduce residential water consumption by approximately 30% (Barrett, 2004). Researchers
predicted that pricing water per unit and hence payment for what water consumers actually use,
would be an effective economic demand management option (Inman and Jeffrey, 2006).
However, it was found that in most cases, water demand is price inelastic because of its low cost
(Espey et al., 1997; Renwick and Archibald, 1998; Hoffmann et al., 2006). Barrett (2004)
reports that the review of 30 residential water price demand studies resulted in almost all
indicating price inelasticisities. However, the effect of water pricing has been found to differ
between location, income and other demographic related parameters. Thomas and Syme (1988)
and Barrett (2004) state that consumers with larger external use were more likely to be sensitive
to price changes while, indoor use is relatively unaffected by cost. Therefore, increasing the cost
of water will have some impact on certain consumers but for pricing to have a significant impact
Chapter 2: Literature Review
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on residential water consumption the cost of water must be greatly increased (Barrett, 2004). On
the Gold Coast, the cost for water in the 2009/2010 financial year is $2.24 per kilolitre ($/kL).
Within five years, water prices in South East Queensland have been predicted to rise to between
$3 and $4/kL (Hertl, 2009). This predicted increase on the cost of water may justify future
research to determine the point at which water consumption would be influenced by price. Such
an investigation would need to be carried out on a city wide scale.
2.5.4 Engineered water efficient devices
Pertinent to the research is the application and measurement of effective savings related to
engineered water efficient devices. Advances in technology have seen the development and
introduction of highly efficient low water use devices. New engineered water use fixtures
include low flush toilets consuming just 3 litres (L) (half) or 4.5 L (full) per flush, clothes
washing machines using as little as 42 L per load, shower heads using as little at 5 L per minute,
taps with aerators that use 1.5 L per minute and dishwashers which use as little as 7 L per wash
(Commonwealth of Australia, 2009). The efficiency of these devices is regulated by WELS. The
use of water efficient devices in households is regulated by the Queensland Development Codes
(2007), hence many existing, and all new dwellings are taking up more water efficient devices.
Retrofitting households with water efficient devices has proved to be very successful, with
savings of 12-50% reported (DeOreo et al., 2001; Mayer et al., 2004; Inman and Jeffrey, 2006).
In the USA, an end use study by Mayer et al. (2004) found that water savings were highest in
toilets and clothes washers with leakage primarily from toilets, significantly reduced. This
investigation involved a pre and post measurement of end use water consumption in 26 homes
in Tampa, USA. This is the only reported retrofit measurement utilising end use water
consumption data in the literature. A larger sample size would assist to confirm the findings and
additional local Australian examples of retrofit investigations would assist to validate the
reported savings.
In Australia, information on the effective water savings achieved by WDM programs is quite
limited and significant differences in both usage and savings are observed between research
findings (Sarac et al., 2002). Estimations of water savings from water efficient devices are often
made in laboratories without consideration of the human behavioural influence on actual water
savings (Biermayer, 2006). These estimations are generally based on American data which
significantly differ from Australian water consumption, for example toilet consumption is
significantly higher in America, average of 13-15 L/flush, than Australia, average of 6-9 L/flush
(Mayer et al., 2004; Roberts, 2005).
Sarac et al. (2002) undertook an investigation to determine the effective bulk water savings
attributed to three separate demand management programs in New South Wales, Australia to
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provide some local data on WDM effectiveness. A comparison group analysis technique was
adopted to estimate the potential impact of WMD programs, which included the ‘house tune up
program’, ‘pilot retrofit program’ and the ‘smart showerhead program’. Before initiatives were
implemented, the groups had relatively similar bulk water consumption. Those residents who
participated in any of the three WDM initiatives were found to consume significantly less bulk
water than those in the control group who had not participated in the WDM initatives. Details of
this invesigation is presented in Table 2-3 (Sarac et al., 2002).
Table 2-3 Savings from various WDM measures (Sarac et al., 2002, pp. 7)
Measures Installed Estimated Savings (kL/a)
Efficient showerhead 14.5 ± 10.3*
Tap aerator / regulator 20.2 ± 40.0
Cistern weight / flush arrestor 11.0 ± 22.3
Tap aerator / regulator and cistern weight / flush arrestor 11.0 ± 18.1
Efficient showerhead and cistern weight / flush arrestor 18.4 ± 7.8*
Efficient showerhead and tap aerator / regulator 19.6 ± 7.8*
Efficient showerhead and cistern weight / flush arrestor and tap aerator / regulator
23.3 ± 6.5*
*significant reduction at a 0.05 level of significance
As displayed in Table 2-3, estimated bulk water savings still have significant error values, due
to the small sample sizes which produced a high variance for estimated savings and confidence
intervals (Sarac et al., 2002). The Sarac et al. (2002) investigation demonstrates the need for
larger sample sizes for evaluating the effective savings attributed to water efficiency of devices
and also triggers the need for more effective and accurate measurement of water consumption
and savings, moving beyond the use of bulk meter read data to more accurate measurement
technologies.
Another Australian study was carried out by Kidson et al. (2006) to estimate water savings from
retrofitting a 4A rated front loading washing machine. A comparison of pre and post bulk water
consumption of households against a control group utilising a regression correction model
technique for the impact of restrictions and climate was adopted to determine end use water
savings. Kidson et al. (2006) calculated water savings of 23.2 ± 5.7 kL/household/annum, which
is a 25% variation. This again demonstrates the need for the accurate measurement of savings
beyond bulk water meters. Stewart et al. (2005) have also made predictions on achievable SEQ
water savings attributed to water efficiency programs with findings stating that a 100%
utilisation of water efficient devices would be likely to reduce internal water demand by 32%.
This estimation is made from end use data from Perth and Yarra Valley and other non-disclosed
literature sources. Again, the reported efforts to understand the effectiveness of initatives often
involves monitoring at a bulk water consumption level, the utilisation of data from different
locations or modelling of water savings without consideration of where, how and why water
Chapter 2: Literature Review
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savings were occuring. The error and variance demonstrated in the measured or calculated water
saving potential of efficient devices underlines the need for accurate data measurement of actual
water savings beyond bulk water consumption.
As previously outlined, the Queensland ‘SEQ Home Waterwise Sevice’ retrofit program was
estimated to result in savings of 4.7 GL/yr or 13.14 ML/d for the 228,511 retrofits completed by
November 2008 (QWC, 2008b). However, no analysis or assessment has been reported in the
literature to determine if this estimated figure is valid, nor has there been any reported follow up
to assess individual household water savings. A similar program in Sydney was evaluated
through bulk meter readings by Turner et al. (2005) with savings of 20.9 ± 2.5 kL saved per
annum. Attempts were made to assess the savings attributed to the individual initiatives in the
program although this was on a bulk meter read scale (Turner et al., 2005). This earlier research
reports that the evaluation of water efficiency in Australia has generally relied on bulk water
meter read data, modelling or estimations to calculate savings.
The importance of monitoring the impact of individual initatives is justified through examples
of water efficient devices actually resulting in an increase in water consumption. Inman and
Jeffrey (2006) report a case where exchanging to lower flow showerheads resulted in increased
bulk water consumption due to the users believing that because they had a water efficient
device, they could shower for a longer duration. Other cases of higher water consumption in
households with water efficient fixtures in eco-friendly subdivisions in SEQ have been reported
by Beal et al. (2008). These examples of increased water consumption, indicates that education
and awareness of sustainable water practises is an crucial component of WDM and that
accurately evaluating and measuring water savings attributed to WDM initatives is vital.
The best example of measuring the water savings attributed to efficient devices is presented by
Roberts (2005) in Yarra Valley who undertook an end use study which detailed the difference in
water consumption for various efficiency levels of shower heads, toilets and clothes washers in
2004. The efficiency of devices was determined through a survey of household water usage
stock in 2003 (Roberts, 2003), followed by the measurement of residential end use in 2004 of
100 homes using smart metering and Trace Wizard© to establish end use water consumption
(Roberts, 2005). Data analysis was carried out by the USA company AquaCraftTM with the
water savings attributed to efficient devices determine through their end use consumption
volumes. While Roberts (2005) investigation is the most accurate measurement of the efficiency
of devices in Australia, it did not consider the impact of residential attitudes on consumption or
the effect of retrofitting and analysis was undertaken by experts from a country with very
different water consumption for devices and households. The differences in location based
consumption, uptake of efficient fixtures and advances in efficiency technology since 2004
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necessitate the need to undertake further research in this field. Mayer et al. (2004) state that the
effective water savings related to WDM initiatives is highly dependent on the characteristics of
water consumers, which consists of attitudes, beliefs and behaviours towards water and the
environment in general. Hence, to understand local water demand and residential consumption it
is imperative to understand the behavioural characteristics of consumers.
2.5.5 Education and awareness
Education of consumers on water conservation practices is essential to encourage and develop
sustainable water consumption behaviour. Knowledge transfer is a key component for changing
behaviour and attitudes towards water use (Webb, 2007). Attitudes and beliefs of consumers
have been found to impact on water use behaviours which, in turn, is linked to water demand
(Hassell and Cary, 2007). Education and awareness of water conservation has been found to
reduce public water usage with earlier research indicating a reduction in water consumption
through education resulting in between 2 – 12.3% savings annually (Nieswaidomy, 1992; Inman
and Jeffrey, 2006). However, determining the effective water savings related to improved
awareness is difficult as this WDM initative is intrinsically linked with other WDM strategies
(Corral-Verdugo et al., 2003). Encouraging residents toward sustainable water consumption
practices requires the instilling of awareness, understanding and appreciation of the environment
and water. Determining motives for saving water and understanding the link between attitudes
and actual behaviour is also paramount when considering educational water saving strategies
(Lant, 1993; Howarth and Butler, 2004).
The connection between attitudes and beliefs concerning water and the environment and their
relationship on actual water consumption behaviour has been established, however empirical
studies quantifying this link are limited (Nancarrow et al., 1996; Hassell and Cary, 2007). For
example, Lawrence and McManus (2008) undertook an investigation to determine the impact of
sustainable lifestyle workshops on water consumption in households. Questionnaires and bulk
meter read household water consumption were utilised with results indicating that the
sustainability programs did not result in significant water savings for residents. This indicated
that the relationship between improved environmental behaviour and actual water savings is not
as straightforward as previously assumed (Lawrence and McManus, 2008). This finding also
suggests that the use of bulk supplied water consumption data may not be suitable for evaluating
the relationship between consumer attitudes and water consumption. Lawrence and McManus
(2008) recommended the use of real and accurate water consumption data rather than bulk meter
read data or estimations derived for assumed behaviour change. Another study conducted by the
CSIRO (2002) revealed that attitudinal variables do affect external or outdoor water
consumption but explicit description of the link between attitudinal factors and actual indoor
end use water consumption was left undescribed. Hence, there is a strong need for further
Chapter 2: Literature Review
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investigation into the effect of attitudes on end use water consumption due to the lack of
empirical studies in the current body of knowledge. This research aims to redress this gap in the
literature and state of knowledge.
2.6 Source Substitution with Recycled Water
Water conservation and the reuse of wastewater and storm water is encouraged by the
Australian National Water Initiative (COAG, 2009). As discussed, alternative sources of water
are critical in augmenting the diminishing supply of potable fresh water (Dimitriadis, 2006;
Dolnicar and Schafer, 2006). Demand reduction and management assist in delaying the need for
new supply sources, however, these alone cannot resolve the pressure on diminishing water
supplies. Alternative sources of water must be made available for consumption as populations
grow and rainfall patterns become increasingly irregular (Dolnicar and Schafer, 2006).
Currently, Australia only recycles between 9 to 14% of all produced wastewater, which is a very
small percentage especially when almost 50% of the water needs of irrigators and urban water
users could be supplied by recycled water (WSAA, 2009a). Australian legislation and standards
specify that a minimum of 20% water reuse should occur by 2012 in individual states or
territories (Shaw, 2009). Actions are underway to achieve this goal with continued investment
in recycling schemes, such as source substitution, resulting in an increase in recycled water
reuse of 118% between 2002 and 2009 (WSAA, 2009a).
In the urban environment, recycled water is defined by the National Water Commission (2006,
pp. 23) as ‘treated effluent that is used by either the water utility itself, a business supplied by
the water utility, or supplied through a third pipe system for urban reuse’. The reuse or recycling
of wastewater for residential use generally occurs through source substitution of potable water
with an alternative ‘fit for use’ water source which does not necessarily require potable water,
for example irrigation, toilet flushing or clothes washing (Hurlimann and McKay, 2006b).
Source substitution has become a well accepted, favoured and utilised method to alleviate the
escalating demand, due to increasing populations, on potable water sources and is promoted as
sustainable and a viable component of the urban water cycle (White and Howe, 1998;
Commonwealth of Australia, 2002; Brown and Davies, 2007). In Australia, one of the most
significant focuses of ‘fit for use’ water substitution and recycled water reuse is through the
application of dual reticulated water supply in new developments (Hurlimann and McKay,
2006a). Recycling or reclaiming water for reuse in specified end uses through a dual reticulation
supply system is well accepted as an effective and sustainable measure of water conservation
(Anderson, 1996; Marks and Zadoroznyj, 2005; Po et al., 2005).
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2.6.1 Dual reticulation
Residential reuse of recycled water occurs through the provision of an additional supply
pipeline referred to as dual reticulated infrastructure. Dual reticulation is a water supply system
comprising of two separate main supplies to the consumer; one potable drinking water and the
other non-drinking recycled water (WSAA, 2002; Gold Coast Water, 2004). In dual reticulated
residential regions, each supply pipe connects to appropriate end uses within the household,
with recycled water supplied for toilet flushing and all outdoor irrigation uses with the exception
of filling pools and spas (Gold Coast Water, 2004; Marks and Zadoroznyj, 2005; Kidson et al.,
2006). The recycled water pipe has a distinctive purple colour to avoid any confusion between
supply pipes.
In Australia’s drought prone environment, the introduction of an additional reclaimed source of
water through dual reticulation enables outdoor use when water restrictions are in place
allowing households the freedom to irrigate externally. Other benefits associated with the reuse
of recycled water include: the utilisation and reuse of a once considered ‘waste’ form of water,
decreasing waste water discharges to the environment and reducing the need to obtain more
potable water (Dimitriadis, 2006; Hurlimann and McKay, 2006b). The downside to having a
second piped supply system is the cost of the second reticulated network and additional
household plumbing required to safeguard against cross connections (Anderson, 1996). The cost
to supply recycled water via dual reticulation has been estimated as $AUD2.50/kL (Anderson,
1996).
2.6.2 The Pimpama Coomera Waterfuture Master Plan
A significant portion of Gold Coast’s residential population growth has been projected to occur
in Pimpama Coomera (PC) in the northern region of the Gold Coast (Po et al., 2003). As this
region was largely undeveloped, GCW set about introducing numerous sustainable water
solutions for the greenfield development. Hence, the Pimpama Coomera Waterfuture (PCWF)
Master Plan was developed by GCW and Gold Coast City Council (GCCC) to ensure the supply
of sustainable water and wastewater services to one of Australia’s fastest growing residential
areas (Po et al., 2003). The population in PC is expected to reach 150,000 by 2056, hence
sustainable IUWRM planning for this region was required (Gold Coast Water, 2008c). The
PCWF Master Plan integrates dual reticulation, rainwater tanks, water conservation through
WDM measures, stormwater management and smart sewers to ensure the sustainable use and
management of water in the region. Figure 2-6, depicts a home with ‘fit for use’ water sources
in the PCWF region.
Chapter 2: Literature Review
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Figure 2-6 Pimpama Coomera Master Plan – household water uses (Gold Coast Water, 2008b)
The PCWF dual reticulation scheme is a centralised distribution system whereby wastewater is
collected in smart sewers (lower infiltration) and treated in a central wastewater treatment plant
(WWTP) (Figure 2-6). This water is then treated to Class A+ recycled water, the highest quality
of recycled water for non-drinking purposes in Queensland, at a recycled water treatment plant
(RWTP) located in Pimpama. Dispersal of Class A+ recycled water to the region occurs through
a separate recycled water line (purple) to all houses within the PC area for approved end uses,
noted in Table 2-4. Class A+ water in the PC region is used for external uses such as irrigation,
car washing or water features, as well as toilet flushing (WSAA, 2002). Detailed in Table 2-4
are recycled water uses for the PC region.
Table 2-4 Class A+ recycled water uses (GCW, 2009b)
Class A+ can be used for Class A+ cannot be used for Irrigation of lawns, gardens, fruit trees and
vegetable crops (fruit and vegetables should be rinsed in drinking water before consumption)
Flushing toilets Washing cars, houses and other similar
outdoor uses Filling ornamental ponds, water features and
fountains Approved commercial, construction and
industry uses Fire fighting
Drinking Cooking or kitchen purposes Personal washing such as baths, showers,
bidets and hand basins Domestic evaporative coolers Washing clothes Swimming pools and spas Recreation, such as playing under sprinklers
and water toys A water source for pets and livestock Filling rainwater tanks or other storages
Domestic End Use Investigation: WDM and Dual Reticulation, R.M. Willis (2010)
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The PCWF scheme is the first in Australia to deliver dual reticulation to a greenfield region
through a centralised distribution scheme. Other residential dual reticulated schemes are
generally introduced on a development by development basis. Initial planning predicted a
reduction in potable water consumption of 84% for households in the PCWF region compaired
to existing communities. Details of predicted water savings are listed in Table 2-5.
Table 2-5 Water use in Pimpama Coomera versus existing communities (Gold Coast Water, 2004)
Existing Communities Pimpama Coomera Master Plan Community Use Water
Source % Water
Used Use Water Source % Water
Used Kitchen, bathroom, laundry, hot water system and external uses
Drinking (potable) water
100% Kitchen and trickle feed to RWT when empty
Drinking (potable) water
16%
Bathroom, laundry, hot water system
Rainwater tank (RWT)
25%
Toilet flushing and external uses
Recycled water 45%
Water saving through WDM measures
14%
It can be seen from Table 2-5 that 45% of existing community consumption is to be replaced by
recycled water and that another 14% of the water demand in 2056 will be met or removed due to
water conservation measures (Gold Coast Water, 2004). The use of rainwater makes up the final
potable water augmentation of 25%. Planning for the scheme was finalised in 2004 with
recycled water coming online in December 2009. Table 2-5 demonstrates where demand
management and source augmentation measures are applied to various end uses. Unfortunately,
the proposed use of rainwater for hot water consumption was not approved which, has altered
the ultimate water savings achievable by the PCWF scheme. To quantify and validate that the
PCWF Master Plan is meeting the estimated water savings, research at an end use level is
necessary to identify the effectiveness of individual initiatives. This research investigation,
described throughout the following chapters, will monitor end use water consumption in the PC
region and determine the effective potable water savings attributed to WDM measures and dual
reticulation. Earlier studies in the dual reticulation and end use water consumption domains
were explored to determine where additional knowledge could be provided.
2.6.3 Overview of dual reticulated schemes in Australia
Numerous residential developments adopting dual reticulation have been implemented in
Australia. Some of the more prominent schemes include Mawson Lakes (Adelaide), New Haven
Village (Adelaide), Rouse Hill (Sydney Water), Aurora (Melbourne), Marriott Waters
(Melbourne) and the PCWF scheme (Gold Coast). Table 2-6 presents an overview of Australia’s
Chapter 2: Literature Review
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in-ground dual reticulation schemes and details estimates or measurements of actual potable
water savings being achieved from the introduction of recycled water.
Table 2-6 Summary of dual reticulated schemes in Australia
Scheme Description Recycled water end uses
Predicted/actual potable water savings
Rouse Hill, Sydney (Sydney Water, 2008)
Online 2001 Will serve up to 36,000 homes Centralised supply system
Toilet & Outdoor uses
Predicted = 40% Actual = 35-40% reduction on total demand
Mawson Lakes, Adelaide (Hurlimann and McKay, 2006b)
Online 2005 Will serve up to 3500 homes
Toilet & Outdoor uses
Prediction = 50% of householder’s water demand (265 kL/year)
New Haven Village, Adelaide (Fearnley et al., 2004)
65 homes Toilet & Outdoor uses
Prediction = 30-40% Actual = 50%
Aurora (VicUrban), Melbourne (Baldwin, 2008)
8,500 lots Development onsite collection & reuse
Toilet & Outdoor uses
Prediction = Up to 45% (recycled water & conservation)
Pimpama Coomera, SEQ (Gold Coast Water, 2004)
Online end 2009 Will serve up to 45,000 homes Centralised supply system
Toilet & Outdoor uses
Prediction = 35-45%
Marriott Waters, Melbourne (Victorian Government, 2009)
Online February 2009 Currently 100 homes On completion 1000 homes Dual reticulated development supply
Toilet & Outdoor uses
Prediction = Up to 40%
The data presented in Table 2-6 demonstrate that recycled water is well utilised in operational
dual reticulated regions and that predictions of uptake have been similar to those measured for
mature schemes. Residents in New Haven Village in Adelaide are using up to 50% of their total
water consumption as recycled water (Fearnley et al., 2004). Residents of Rouse Hill use
between 35-40% of their total household water consumption as recycled water (Kidson et al.,
2006; Sydney Water, 2008). The price of recycled water was determined to be an important
issue especially in Rouse Hill where residents were consuming higher volumes of total water
than residents in conventional single reticulated suburbs when the price of recycled water was
just 28 cents/kL compaired with potable water at 98 cents/kL.
As demonstrated, numerous dual reticulation schemes have been planned and implemented with
the potential demand of recycled water estimated and bulk metered water consumption figures
reported on when available. To date, no investigation has been undertaken in Australia or the
world, to detail the end use consumption of recycled water in dual reticulated regions (WSAA,
2002). It is important to undertake such investigations to determine what percentage of water is
consumed through irrigation and toilet flushing so this data can assist in the determination of the
variation in supply required in peak and low demand times.
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This research seeks to fill this gap in knowledge by investigating the potable and recycled end
use water consumption of the greenfield dual reticulated Pimpama Coomera scheme located in
the Gold Coast, Queensland. To meet this objective, advanced water consumption monitoring
technologies were adopted.
2.7 Advanced Water Consumption Monitoring Technologies
Advanced water consumption monitoring technologies, such as smart metering, allow for the
collection of detailed water consumption data. As discussed, gaining empirical evidence of how
and where water is used and determining the effectiveness of specific WDM strategies and
source substitution initiatives is critical for planners, utilities and conservation professionals.
Planning a secure supply of water for future demand, requires the use of a range of consumption
estimations and assumptions on the effective savings attributed to demand management
initiatives or substituted supplies (Turner and White, 2006). Advanced water consumption
monitoring technologies provide a platform to collect accurate data to verify some of the
estimations made in water planning process. Details on current advanced water consumption
monitoring technologies are presented.
2.7.1 Smart metering
Smart meters provide additional high quality water use information, such as end use or leakage
data, which benefits water utilities and policy makers alike (Giurco et al., 2008b). Smart
metering couples two distinct elements for the collection of such disaggregated water
consumption data: technologically advanced meters that capture water use information, and a
communication system which both captures and transmits usage information in real or almost
real time intervals (New York State Energy Research and Development Authority, 2003). The
three essential functions performed by smart water meters are: automatic and electronic data
capture, collection, and the communication of water usage data (real time or almost) (Idris,
2006). In practice, a smart water meter configuration involves a high resolution water meter
linked to a data logger, which captures water use data that can be downloaded as an electronic
signal and analysed using available technology (Britton et al., 2008; Stewart et al., 2009). The
electronic signals from smart meters can also be transferred to computers or central data hubs
via data distribution technologies like the GSM network (Hauber-Davis and Idris, 2006). An
example of a smart water metering set up is displayed in Figure 2-7.
Chapter 2: Literature Review
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Figure 2-7 Typical smart meter set up in residential household (Stewart et al., 2009)
Smart metering technology has enabled the accurate and reliable measurement of water
consumption data of a range of resolutions, which is useful for identifying the effectiveness of a
variety of WDM measures. The resolution of the water meter and data loggers utilised in the
smart metering system determines the richness of data obtained. Current, large scale smart
metering systems utilised for leak detection, peak demand identification and time-of-use tarriffs
have lower resolution water meters and only log at hourly intervals as this is adequate for the
information required (Stewart et al., 2009). Detailed end use water consumption data requires a
smart metering system with higher resolution water meters and data loggers that record
information in 5-10 second intervals (Giurco et al., 2008a). Figure 2-8 demonstrates several
WDM and source substitution initatives with the need for smart metering to determine effective
water savings indicated. More than half of the displayed initiatives require a smart metering
approach to effectively determine and measure the water saving potential.
New Dwelling Development City
Existing Dwelling
Pricing
Restrictions
Volumetric charges, seasonal, time of use
Optimise rules for frequency and duration, drought pricing
Recycling
Desalination $
Stormwater
Efficiency
Rain tanks $
Leaks Role for smartmetering
SCALE
Figure 2-8 Potential for demand reduction and alternative supply options across scales (Stewart et al.,
2009)
Domestic End Use Investigation: WDM and Dual Reticulation, R.M. Willis (2010)
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Figure 2-8 shows that obtaining high level disaggregated data through smart metering allows for
identification of actual water savings of differing WDM or source substitution initiatives (Inman
and Jeffrey, 2006). Figure 2-9 demonstrates the increasing cost and complexity required to
measure various WDM initiatives, which instigates the need for more complex advanced smart
metering configurations.
Figure 2-9 Matching technologies to objectives (Giurco et al., 2008a)
Advanced smart metering technology allows for the capture of high resolution end use water
consumption data, which is necessary to ascertain the water savings attributed to individual
WDM programs. Figure 2-9 further demonstrates that end use data is imperative to determine
the effectiveness of most demand management measures such as efficiency and education, and
is also required for restrictions and pricing effectiveness. End use monitoring is also useful for
evaluating, measuring and validating planning the demand and supply of water (White and
Fane, 2001).
2.7.2 End use studies
Water end use studies provide the necessary data for the determination of where, when, how and
why residents consume water in the home (White, 2001; Giurco et al., 2008a). The purpose of
an end use study is to determine water consumption in individual household end uses which
include shower, toilet, tap, irrigation, clothes washer, dish washer, leaks and evaporative air
conditioners (Gato, 2006). Figure 2-10 details household water end uses.
Chapter 2: Literature Review
- 39 -
Figure 2-10 Household end uses of water
End use studies allow for the dissemination of technological and behavioural aspects of water
consumption and they offer ‘significant opportunities for providers to improve water service
delivery and long term planning’ (Giurco et al., 2008a, pp. 1). End use studies also provide
(Gato, 2006; Giurco et al., 2008a):
Valuable information on daily demand patterns;
Seasonal variations in water consumption;
The split of indoors versus outdoor consumption;
The actual water use for fixtures and fittings;
Information for water planning and design;
The ability to measure the effectiveness of WDM initatives, geographical or community
variations in consumption; and
Assistance in detecting leaks.
Such data are pertinent for daily demand forecasting and for the refinement in the planning and
management of water demand and supplies for regions (Gato, 2006; Schlarfrig, 2008). Giurco et
al. (2008a) emphasise that there is limited data on end uses in Australian cities and towns
despite the fact that several end use studies have been undertaken in the country. This is due to
the unique climate, tourism and consumption characteristics of each city or town and also the
dramatic changes seen in water consumption over years. Schlarfrig (2008) states that there is
Domestic End Use Investigation: WDM and Dual Reticulation, R.M. Willis (2010)
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increasing recongnition for the need of more comprehensive and frequent end use studies.
Giurco et al. (2008a) and WSAA (2003) recommend further research in the end use water
consumption field. Mayer and DeOreo (1999) also stipulate the need for location and country
based research due to per capita consumption being significantly variable between regions and
populations within the world.
The first recorded end use study was undertaken in the USA by Brown and Caldwell (1984)
with the objective of measuring end uses of water in residential structures through
instrumentation and laboratory testing. This investigation of 200 homes determined water use
for fixtures and water conservation devices with estimations made on the frequency of use,
duration and flow rate. The result of the investigation saw estimated savings of water
conservation devices spanning a range of 300%, hence Mayer and DeOreo’s (1999) observation
on the need for precise end use water consumption data on individual residential water uses
measured through advanced metering techniques. The concept of measuring residential end uses
of water through the collection of instantaneous water consumption flow data was realised by
AquaCraft® between 1994 and 1996 in the USA (DeOreo and Mayer, 1994). AquaCraft
developed the Trace Wizard© software to automatically disaggregate flow traces into household
end uses (DeOreo et al., 1996), they subsequently carried out the USA AWWA (1999) and
Tampa (Mayer et al., 2004) end use studies. Some critisism occurred from Koeller and Gauley
(2004) on the data logging and Trace Wizard© methodology used to determine water end use.
Koeller and Gauley (2004) reported a pilot trial from a single (1) home focussing on toilet
flushing and stated that errors occur in the program when simultaneous events (an event on top
of another) occurred. This resulted in the underestimation of the volume and number of events
for toilets and tap use. It was recommended that the Trace Wizard© software was refined to
allow the user to visually inspect and allocated overlapping or simultaneous events (Koeller and
Gauley, 2004). DeOreo and Mayer (2004) responded to this through the presentation of results
from end use studies which demonstrated consistency of end use results, that the number of
toilet flushes were accurate, that toilet flush volumes were recorded at a 95% confidence
interval and they presented the upgraded version of Trace Wizard©, which had refined the
simultaneous events issue, was avaliable at the time of the Koeller and Gauley (2004) report.
DeOreo and Mayer (2004) report that the accuracy of end use analysis was improved through
program refinement. It was also suggested that improved end use data accuracy can be obtained
through independent analysis of data by several analysts and through undertaking a home visit
or audit to assist in determining water use fixtures and behaviours of the home being analysed.
The question of the accuracy of Trace Wizard© is acknowledged with the developers further
discussing the accuracy and limitations of the software. The result of this debate was the
continued use of Trace Wizard© as the worldwide end use analysis tool.
Chapter 2: Literature Review
- 41 -
End use studies have also occurred in Yarra Valley (Melbourne), Perth and Toowoomba in
Australia and the Kapiti Coast in New Zealand. Table 2-7 summarises the results from the most
recent worldwide end use studies. Reported data is from single detached households only all
analysed using Trace Wizard©.
Table 2-7 Summary of findings from other water end use studies
Author Study title Country Region No. homes
Avg. consumption (L/p/day)
End use or additional factors investigated
Mead (2008)
Investigation of Domestic End Use
Australia Toowoomba
10 Indoor & outdoor = 122
End use only
Heinrich (2007)
Water End Use and Efficiency Project (WEEP)
New Zealand
Kapiti Coast
12 Indoor & outdoor = 184.2 Summer: 203.9 Winter: 168.1
End use only
Roberts (2005)
Residential End Use Measurement Study (REUMS)
Australia Yarra Valley
100 Indoor = 169 Outdoor = extra 20% = 34
End use only
Mayer et al. (2004)
Tampa Water Department Residential Water Conservation Study
United States of America
Tampa 26 Pre retrofit = 752.9 Post retrofit = 403.9 (indoor & outdoor)
End use and retrofitting
Loh (2003)
Domestic Water Use Study
Australia Perth 124/ 120
Indoor = 155 Outdoor = extra 54% = 83.7
End use only
AWWA (1999)
Residential End Uses of Water (REUW)
United States of America
12 regions
1188 Indoor = 262.3 Indoor & outdoor = 650.3
End use only
Table 2-7 demonstrates the variability between the sample sizes, ranging from as little as ten
homes to an impressive 1188 homes along with the average consumption in litres per person per
day (L/p/d). Indoor consumption between the Yarra Valley and Perth studies differ just slightly
by 14 L/p/d, while the most recent Toowoomba study recorded just 122 L/p/d of indoor use,
which is significantly less than that found previously. Significant drops in average water
consumption, advances in efficiency technology and the most recent end use study in
Toowoomba together stress the need to undertake further research in this field. Outdoor usage
varies significantly between the Australia studies with a range of 0 – 54% demonstrated (0% in
Toowoomba due to extreme drought and outdoor restictions). When comparing countries, the
total, indoor and outdoor water consumption rates differ significantly. Such sizeable
consumption differences in total, indoor and outdoor end use consumption between the location
specific end use studies reiterate the need for region and local based end use research. The end
use breakdown of the Asia-Pacific studies is displayed in Table 2-8.
Domestic End Use Investigation: WDM and Dual Reticulation, R.M. Willis (2010)
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Table 2-8 Comparison of Asia-Pacific end use water consumption studies
Previous studies Perth (2003) Melbourne (2005)
Yarra Valley Auckland (2007) Toowoomba
(2008) L/p/d Percent L/p/d Percent L/p/d Percent L/p/d Percent Clothes washer 42.0 13% 40.4 19% 39.9 24% 27.7 22.7% Shower 51.0 15% 49.1 22% 44.9 27% 53.1 43.5% Tap 24.0 7% 27.0 12% 22.7 14% 18.9 15.5% Dishwasher NA NA 2.7 1% 2.1 1% 2.6 2.1% Bathtub NA NA 3.2 2% 5.5 3% 3.4 2.8% Toilet (total) 33.0 10% 30.4 13% 31.3 19% 15.6 12.8% Irrigation (total) 180† 54% 57.4† 25% 13.9 8% 0.5 0.4% Leak (total) 5.0 1% 15.9 6% 7.0 4% 0.5 0.4% Other NA NA 0.0 0% 0.8 0% 0 0% Total Consumption
335.0 100% 226.2 100% 168.1 100% 122.2 100%
†Note: Irrigation volume per person calculated from provided volumes per household and end use break downs.
Table 2-8 demonstrates the variability between the breakdown for end uses in both percentage
and volume. One example is the percentage use for showering which ranges from 15% in Perth
to 43% in Toowoomba but when considering shower volumetric consumption Toowoomba
residents use 53.1 L/p/d and Perth residents use 51 L/p/d which is not significantly different.
Again, this variance between indoor and outdoor consumption demonstrated from earlier end
use studies reiterates the need for location specific research. To date, no statistically significant
end use investigation has been undertaken in Queensland, Australia as the Toowoomba study
only evaluated ten homes. Queensland has a unique climate and community with shifting water
consumption patterns, water use fixtures, attitudes and behaviours. The Toowoomba evaluation
demonstrates the differences in consumption between other Australian locations and
Queensland. The fact that no statistically significant end use study has been carried out in
Queensland warrants the need for this research.
2.8 Research Justification
This section outlines the need for this research by summarising the current state of knowledge
and emphasising the gaps in the literature. A trend of lower rainfall and more frequent drought
periods in southern Australia combined with growing populations, has triggered the need for
integrated urban water resource management. Planning and implementation of supply, demand
and source substitution water measures has occurred throughout the nation but the monitoring,
evaluation and review of these initiatives has not (Turner and White, 2006).
Turner and White (2006), Turner et al. (2007b) and WSAA (2008) document the importance of
water utilities evaluating and monitoring source substitution and demand management programs
to determine the actual water savings achieved. This assists in ensuring the improvement of
Chapter 2: Literature Review
- 43 -
water management programs for the realisation of the desired long term savings. Chambers et
al. (2005, p 35) state that ‘more data and information should be collated on the effectiveness and
sustainability of demand management techniques, to improve long term forecasting’. Turner et
al. (2007b) state that very little evaluation has been undertaken on the millions of dollars spent
to implement water management programs, and that the ongoing evaluation of savings,
participation rates and costs as well as customer satisfaction of demand management programs
is essential to ensure that predicted savings are achieved, maintained and that costs are
minimised. This is supported by WSAA (2003) and Turner and White (2006). Hence, it is
strongly suggested that gaining empirical evidence of how and where water is used and
determining the effectiveness of specific WDM strategies is critical for planners, utilities and
conservation professionals. Data with high levels of disaggregation, such end use water
consumption data are required to achieve this (Turner et al., 2005; Inman and Jeffrey, 2006).
Gathered information can be fed into future water demand and supply forecasting models for
increased accuracy of water services planning (WSAA, 2003; WSAA, 2008).
2.8.1 Water end use and demographics
Water end use data is collected through advanced water metering technology, which involves a
high resolution water meter and data logger configeration. End use water consumption data
demonstrates when, where and how water is being used in the home. Such data is also pertinent
for daily demand forecasting and for refinement of the planning and management of water
demand and supply for regions (Gato, 2006). End use studies have occurred in Yarra Valley,
Perth and Toowoomba in Australia and across the world in the USA and New Zealand. The
need to undertake location specific end use studies is particularly critical due to the differences
in per capita consumption and individual end use consumption reported in earlier studies
(Mayer and DeOreo, 1999; White and Fane, 2001; Turner et al., 2005).
Despite several end use studies having occurred in Australia, Both Giurco (2008a) and WSAA
(2003) state that there is limited end use data available and recommend further research in the
end use water consumption field. Schlarfrig (2008) states that end use studies of greater
comprehensiveness and frequency are needed. Household consumption has been found to be
influenced by the number of people in the house, the age of residents, education levels of
residents, lot size of properties, residents’ income, efficiency of water consuming devices (i.e.
clothes washers, shower heads, tap fittings, dishwashers and toilets) and the attitudes, beliefs
and behaviours of consumers (Nieswaidomy and Molina, 1989; Renwick and Archibald, 1998;
Mayer and DeOreo, 1999; Renwick and Green, 2000; Inman and Jeffrey, 2006).
To date, no statistically significant end use investigation has been undertaken in Queensland,
Australia with the Toowoomba study only evaluating ten (10) homes. This study satisfies the
Domestic End Use Investigation: WDM and Dual Reticulation, R.M. Willis (2010)
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need for a statistically significant end use water consumption investigation in South East
Queensland. Data will be utilised to improve demand forecasting, to understand the
consumption characteristics of residents on the Gold Coast and to determine the effectiveness of
various water demand management and source substitution initatives.
2.8.2 Engineered efficient devices, consumer attitudes and water end use
Engineered water efficient devices have been introduced throughout Australia with estimations
made on the relative water savings attributed to these devices. These water savings are often
determined under laboratory conditions, estimated from bulk water meter read consumption data
and calculated through modelling. While this approach is often applied to determine
effectiveness, it is well documented that to understand the actual water savings attributed to
demand management measures such as water efficient devices, end use water consumption data
is required (Mayer et al., 2004; Turner et al., 2005; Giurco et al., 2008b). Only one end use
study reported the effectiveness of various device efficiencies (Roberts, 2005). This study was
completed in 2004 with significant changes in total consumption, consumer attitudes and
advances in efficiency occurring between 2004 and today. End use data is necessary to
determine the effectiveness of other demand management measures such as restrictions, the
efficiency of devices, behaviour change initiatives and pricing. A case of efficient showerhead
exchange which resulted in an increase in water consumption due to the belief that water
savings would occur specifically because of the efficient device was reported by Inman and
Jeffrey (2006). This example triggers the importance of understanding behavioural and
attitudinal characteristics of residents on consumption, which also requires monitoring at an end
use level. The connection between attitudes and beliefs concerning water and the environment
and their relationship on actual water consumption behaviour has been established however
empirical studies divulging this link are limited (Nancarrow et al., 1996; Hassell and Cary,
2007). Lawrence and McManus (2008) recommend the use of real consumption data not
estimations derived from assumed behaviour change.
This study will investigate the effect of water efficient devices, educational devices, and
behaviours and attitudes on end use water consumption. A significant gap is present in the body
of knowledge of just how these factors influence end use water consumption. Data from this
research can be used to improve the design of conservation programs, provide justification for
continued support of programs and will assist in the development of the most effective water
demand management programs for continued water savings. Similar research on the
effectiveness of source substitution is also essential.
Chapter 2: Literature Review
- 45 -
2.8.3 Recycled water end use
Recycled water reuse is strongly encouraged in Australia (COAG, 2009). One of the preferred
methods of recycled water supply for residential consumption is through dual reticulated
infrastructure, which supplies recycled water to specified end uses. In Australia, there are six
operating recycled water dual reticulation supply schemes with several bulk meter read water
consumption figures detailed. To date, no investigation has been undertaken in Australia or the
world, to detail the end use consumption of recycled water in dual reticulated regions (WSAA,
2002). It is imperative to undertake such investigations to determine what percentage of water is
consumed through different end uses like irrigation or toilet flushing. This study will provide
much needed data on the variation in supply required in peak and low demand times for
recycled water infrastructure. This research seeks to fill this gap in knowledge by investigating
the potable and recycled end use water consumption of the greenfield dual reticulated Pimpama
Coomera scheme located in the Gold Coast, Queensland. Inherently, this study will also
determine the water savings ascribed to the greenfield Pimpama Coomera Waterfuture scheme.
This data will assist in determining the water savings attributed to source substitution through
recycled water and the potable water savings related to water demand management initiatives, in
turn assisting to verify design assumptions.
To summarise, this research involves the monitoring, evaluation and review of several demand
management and source substitution initiatives at an end use level. In Australia, no end use
water consumption investigations have been carried out to establish the water savings attributed
to water efficient devices since 2005, educational devices or the impact of attitudes and
perceptions on actual water use behaviour. Furthermore, no statistically significant end use
water consumption investigation has been undertaken in Queensland, Australia. This is also the
world’s first investigation to monitor, evaluate and review the end use water savings attributed
to a dual reticulated greenfield scheme.
2.9 Chapter Summary
This chapter provided a review of literature pertinent to the topics surrounding the water
situation in Australia, intergrated urban water resources management, water demand
management, source substitution and advance water monitoring technology for monitoring end
use water consumption. It is well documented that the management of water to ensure a secure
supply for growing populations is pertinent. The principles of IUWRM have involved the
introduction of supply, demand and source substitution options throughout the nation. While
IUWRM has been introduced throughout Australia, minimal investigation has been undertaken
to determine the effective water savings attributed to demand and source substitution planning
mechanisms. Research that has been reported, is based on bulk metered read data or estimations
Domestic End Use Investigation: WDM and Dual Reticulation, R.M. Willis (2010)
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and modelling. Empirical evidence of the effective water savings attributed to the various
demand and source subsitution initatives is very limited. Moreover, the importance of
undertaking local specific research is paramount due to the variations in local consumption,
fixtures, behaviours and attitudes. Adopting an end use investigation is justified and indeed
required to assess the effectiveness of WDM initatives and to provide detail on the effectiveness
of source substitution measures. While several end use investigations have been undertaken in
Australia, the requirement and call for more data and research is this area is well reported. This
review of the literature provided the required knowledge and understanding of all relevant
IUWRM, WDM, source substitution and end use areas. The determination of current gaps in the
body of knowledge assisted in focusing this research. The chapter concluded with a summary of
current gaps and a formulated research approach motivating this research investigation. The
research method adopted to undertake this research is detailed in Chapter 3.
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Chapter 3
Research Method and Design This chapter details the research methodology and design adopted for this study. Specified
within are the research approach, design and analytical techniques adopted to satisfy the
developed research objectives. An explanatory mixed methods design was selected as the most
suitable approach to suit the diverse research objectives. An overview of this design is presented
together with specific details on the quantitative and qualitative methods and techniques
utilised. The overarching mixed method framework highlighting the three project phases is
presented initially. Detailed diagrammatic models and discussion then follows for the three
primary research phases and the individual stages within each phase of the research.
3.1 Overview of Research Method and Design
This study adopts a mixed method design through the collection, analysis and combination of
both quantitative and qualitative data and research approaches through the various phases of the
research process. The amalgamation of quantitative and qualitative approaches provides a better
understanding of the research questions and problem, strengthens the research design and
completes the research through the provision of more detailed qualitative data to complete the
quantitative component of the research (Creswell and Plano Clark, 2007; Creswell, 2008).
Brewer and Hunter (1989, pp. 28) state that mixed methods is a ‘legitimate inquiry approach’
while the combination of quantitative and qualitative data is said to provide a ‘very strong mix’
(Miles and Huberman, 1994, pp. 42). Mixed methods offset the weaknesses of both quantitative
and qualitative research providing strength to the methodology; it assists in answering questions
which cannot be answered by one method alone; it provides comprehensive evidence for
research problems; and allows the use of multiple methods to address research problems
(Creswell and Plano Clark, 2007). Mixed methods can also be considered as ‘merging,
integrating, linking or embedding’ both the quantitative and qualitative strands of research
(Creswell, 2008, pp. 552). A mixed method approach was adopted due to the array of data types
required to meet the developed research objectives. The explanatory mixed method design was
determined to be the most applicable of the four potential mixed method approaches, to satisfy
the research objectives (Creswell, 2008).
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3.1.1 Explanatory mixed method design
Creswell’s (2008) ‘explanatory design’ for mixed methods was determined to be the most
appropriate design for this research. The primary purpose of the explanatory mixed methods
design is that ‘qualitative data help to explain or build upon initial quantitative results’ to
explain significant or non-significant results and surprise or outlier results (Morse, 1991;
Creswell and Plano Clark, 2007, pp. 71). Figure 3-1 demonstrates the basis of the explanatory
mixed methods research design.
Figure 3-1 The explanatory mixed methods design (Creswell and Plano Clark, 2007)
Figure 3-1 demonstrates the emphasis on quantitative data and results (hence in capitals) while
qualitative data is used to help identify, refine and further investigate relationships in the
quantitative data. This process is required due to the researcher needing to understand the
quantitative data and the contributing factors before undertaking qualitative data analysis to help
build or explain the quantitative results (Creswell, 2005).
Creswell and Plano Clark (2007, pp. 72) introduce two variations of the explanatory design
being the ‘follow-up explanations model (QUAN emphasized)’ and the ‘participant selection
model (QUAL emphasized)’. The explanatory design suited for this research was the ‘follow-up
explanations model’ which is used when emphasis is placed on the quantitative data with
qualitative data required to expand or explain the quantitative results. A diagrammatic
representation of the follow-up explanations model for mixed methods as utilised in this
research is presented in Figure 3-2.
Figure 3-2 Explanatory design: follow-up explanations model (QUAN emphasised) (Creswell and Plano
Clark, 2007)
Figure 3-2 demonstrates the prioritisation on quantitative data collection, analysis and results
with qualitative data collection, analysis and results used as a follow-up. This process is vital to
strengthen or help explain the central quantitative data. The characteristics of explanatory
research, specifically the follow-up explanations model are detailed below, adapted from
Creswell and Plano Clark (2007) and Creswell (2008, pp 560):
Chapter 3: Research Method and Design
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Both quantitative and qualitative data is collected sequentially in different phases i.e.
quantitative data is firstly collected followed by the collection of qualitative data;
Generally quantitative data is collected first and to help ‘explain or elaborate’
quantitative data, qualitative data is then collected in succession;
Basically the qualitative data is needed to extend, explain or refine the general picture
of the research problem established through the quantitative data;
A priority is placed on the collection and analysis of quantitative data, the second phase
of the research consists of a smaller qualitative component;
Qualitative data is used to refine the results or findings from the quantitative data; and,
The explanatory design captures the best of both quantitative and qualitative data.
All research methodologies possess certain strengths and weaknesses. Table 3-1 details the
relevant strengths and weaknesses of the explanatory mixed methods design.
Table 3-1 Strengths and weaknesses of Explanatory Mixed Methods (Creswell, 2008)
Strengths Weaknesses
Most straight forward mixed method approach A large amount of time required
Conducted in two methods in separate phases
Only one type of data collected at a time
Qualitative phase will take longer than quantitative phase
Single researcher can carry out method
Reporting can occur in two phases
Multiphase investigations
Appeals to quantitative researchers as strong quantitative origin
Researcher needs to determine whether to use the same individuals for both phases
Researcher cannot specify how individuals will be selected for qualitative phase leading to problems with internal review
Researcher determines who to select for qualitative phase
The strengths of the explanatory mixed method design, detailed in Table 3-1, assisted in the
resolution that this was the most appropriate mixed methodology for the research. The
weaknesses presented Table 3-1 were overcome by the use of research assistants, using the
same research sample for quantitative and qualitative analysis and project management and
planning to ensure sufficient time to undertake the qualitative component of the research.
Data analysis for this study followed the traditional explanatory research design through the
collection and basic analysis of quantitative data and then the collection, analysis and use of
qualitative data to assist in strengthening the results of the quantitative data. Quantitative data
were in the form of natural science end use water consumption data, with the collection of
qualitative water consumption behaviours data through household water audits. Further
quantitative and qualitative data was also collected through demographic and attitudinal
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surveys. A brief overview on theory supporting specific quantitative and qualitative research
methods is described below.
3.1.2 Quantitative research
Creswell (2007, pp. 74) defines quantitative research as ‘a type of research where the researcher
decides what to study; asks specific, narrow questions; collects quantifiable data from
participants; analyses this numerically, usually with statistics; and conducts the inquiry in an
unbiased, objective manner’. Quantitative research aims to test an existing theory and either
refute or support it (Creswell, 2008). Literature plays a major role in justifying the problem and
identifying questions and hypotheses (Creswell and Plano Clark, 2007). Quantitative research
tests specific variables and aims to explain the relationship between variables, with closed
questions asked to test this (Creswell and Plano Clark, 2007). Precisely testing hypotheses and
measuring variables linked to causal relationships is the aim of quantitative researchers
(Creswell and Plano Clark, 2007). Data consist of measurable, numeric and observable data
while data collection is often through predetermined instruments and a large number of
participants are investigated (Neuman, 2003). Analysis and interpretation of data is statistical
and involves trend analysis of variables, determination of variable relationship, hypothesis
testing and comparisons with past studies (Creswell and Plano Clark, 2007). Quantitative
research generally produces objective and unbiased reports due to the predictable pattern,
procedures and controls which eliminate bias (Creswell, 2008). The use of quantitative methods
aims to verify results of past research, the subjects, settings and methods will vary but concept
testing will be the same (Vogt, 2007).
In this study, quantitative end use water consumption data and closed-ended survey questions
were completed. This data was analysed to determine key trends or significant factors with,
qualitative water stock and behavioural audits and open-ended survey questions utilised to assist
in the analysis of the collected quantitative data and to explore and further understand trends
displayed in the data.
3.1.3 Qualitative research
Creswell (2008, pp. 232) defines qualitative research as ‘a type of research in which the
researcher relies on the views of participants; asks broad, general questions; collects data
consisting largely of words (or text) from participants; describes and analyses these words for
themes; and conducts the inquiry in a subjective, biased manner’. Qualitative research aims to
learn the views of participants on particular phenomenon and to examine social processes
(Creswell, 2005). Literature plays a minor role in qualitative research but aids in justifying the
research problem (Neuman, 2003; Creswell, 2008). The aim of qualitative research is to gain an
Chapter 3: Research Method and Design
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understanding of participants experiences and to understand the intricacy of the phenomena; to
achieve this open-ended questions are asked (Sekaran, 2000). The empirical data is in the form
of words, gestures and tones and observation of behaviours which are collected from
participants and analysis consists of determination of patterns, themes and generalisations
(Creswell, 2008). Validity of qualitative research relies on the researcher and is often reflective,
without due attention hence, the research has the potential to be biased (Neuman, 2003;
Creswell and Plano Clark, 2007).
Qualitative methods were applied in this research to gain valuable ethnographic data to assist in
determining water use behaviours and activities of participants. The explanatory mixed
methodology defines qualitative data as data that ‘helps explain or build upon initial quantitative
results’ (Creswell, 2008). Hence, the qualitative research methods discussed in this section and
in subsequent sections have been selected to compliment and add value to the quantitative
components of the study.
3.1.4 Explanatory mixed methods: follow-up explanations model design
The research was undertaken with a mixed methods approach due to the multifaceted objectives,
which dictate the requirement of both quantitative and qualitative approaches and data. The
research method utilised was an explanatory mixed methods approach. The research design
serves as a blueprint to meet the developed objectives hence it is imperative to ensure that it is
robust. The research design involves a series of rational decision making choices including the
type of sample and data collection methods, the variables to be measured and determination on
the analysis techniques for the concepts and variables. The ‘follow-up explanations model’
design was adopted as the most appropriate approach to meet the research objectives.
The broader explanatory mixed methods follow-up explanations design and activities are
demonstrated in Figure 3-3. This mixed methods design is separated into three distinct phases
with the first being the acquisition of knowledge required to undertake the research. The
following two phases are based on satisfying the primary objectives of the research being to
investigate water end use and the effect of demand management initiatives and an investigation
into the end use water consumption in a dual reticulated recycled water region. The research
output from each research phase, in the form of a chapter or referred publications, is detailed.
Domestic End Use Investigation: WDM and Dual Reticulation, R.M. Willis (2010)
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Phase 1: Knowledge Acquisition
Phase 2: Water End Use & Demand Management
Phase 3: Dual Reticulated Recycled Water
Stage 1a: Literature Review
Stage 1b: Set Research Objectives
Stage 1c: Research Method
Stage 2b: Obtain consenting sample
Stage 2c: Potable end use water consumption data
Stage 2d: Stock survey and water use behaviour audit
Stage 2e: Potable end use water consumption
Stage 2f: Questionnaire development, distribution and analysis
Stage 2g: Shower monitor investigation
Stage 3a: Predictive dual reticulated recycled water uptake model
Stage 3b: Dual reticulated recycled end use water consumption data collection and analysis
Stage 3c: Dual reticulated recycled water end use consumption
Stage 2a: End use water consumption design
PHASE STAGEOUTPUT/REFEREED
PUBLICATION
Chapter 1: Introduction
Chapter 2: Literature Review
Chapter 3: Research Method and Design
Chapter 5: Gold Coast Domestic Water End Use Study
Chapter 6: Revealing the impact of socio-demographics factors and efficient devices
on end use water consumption: case of Gold Coast, Australia
Chapter 7: Quantifying the influence of environmental and water conservation attitudes on household end use water
consumption
Chapter 8: Alarming visual display monitors affecting shower end use water
and energy conservation in Australian residential households
Chapter 9: Pimpama-Coomera dual reticulation end use study: pre-commission
baseline, context and post-commission end use prediction
Chapter 10: Domestic Dual Reticulated End Use Pimpama Coomera, Gold Coast,
Australia
Chapter 11: Conclusions, Contributions and Implication
Chapter 4:Situational Context and Descriptive Data Analysis
Pub
Pub
Pub
Pub
Pub
Pub
Pub = Referred Publication
Figure 3-3 Overarching mixed methods research design
As demonstrated in Figure 3-3, Phase 1 involved the accumulation of knowledge, the
development of research objectives and determination of the research method and design. Phase
2 focused on determining potable water end use and the assessing the effectiveness of demand
management initiatives. Phase 3 comprised the development of a predictive model for recycled
water use and then measurement of actual end use uptake of recycled water in the Pimpama
Coomera dual reticulated greenfield region. Conclusions, limitations and future research are
Chapter 3: Research Method and Design
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addressed in the final chapter. Sections 3.2 to 3.4 elaborate on each of the three phases of the
wider research design through comprehensive individual phase and stage diagrams and an
associated discussion.
3.2 Phase 1: Knowledge Acquisition
The objective of Phase 1 of the research was to undertake a literature review of national and
international literature, to develop research objectives and to determine the most appropriate
design for the research methodology. Figure 3-4 demonstrates the research activities undertaken
to achieve the objectives of this phase.
Figure 3-4 Phase 1 research activities and output
An extensive review of past literature was carried out to accumulate knowledge and to
determine current gaps in the field of research, as detailed in Figure 3-4. Numerous topics were
investigated such as: the water situation, integrated urban water resource management, water
demand management, source substitution, dual reticulated recycled water, advanced water
metering and end use water consumption. Chapter 2 details all of the explored topics of
literature. Moreover, Chapter 5 to 10 provide concise literature reviews associated with the
refereed publications. The obtainment of knowledge through the literature review allowed for
the determination of current gaps in the field which resulted in the development of research
objectives. After the determination of research objectives, additional literature was reviewed to
ascertain the most applicable research method and design to meet the objectives. Resolution on
an explanatory mixed methods approach occurred due to the multiple data sources required to
satisfy the quantitative and qualitative objectives. Phase 1 of the research, displayed in Figure
3-4, resulted in the determination of gaps in the body of knowledge, development of the
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research objectives and the determination on the explanatory mixed methodology as an
appropriate research design. Each stage in Phase 1 was necessary before commencing Phases 2
and 3.
3.3 Phase 2: Water End Use and Demand Management
The purpose of Phase 2 was to undertake an end use investigation of potable water consumption
and to determine the effective end use water savings attributed to various water demand
management initiatives. A model presented by Guirco et al. (2008a) for designing end use
measurement studies was utilised in the initial stages of Phase 2 (Figure 3-5).
Figure 3-5 End use measurement study design cycle (Giurco et al., 2008a)
True to this model, the design of the end use measurement study involved the definition of
research objectives, practical determination of the data requirements and the technology
required to satisfy the objectives of the research. Determination of the sample size and any
constraints on the chosen end use measurement path concluded the study design. The final
research design for Phase 2 resulted in seven stages being required to investigate all facets and
interrelationships between the water end use and demand management components of the study.
These phases included obtaining end use water consumption for the consenting sample, to
carryout stock and behavioural investigations, complete questionnaires and to investigate the
impact of various WDM initiatives. Phase 2 involves the consideration and determination of the
end use research design, data requirements, technology, sample size and other aspects of the end
use measurement and demand management research. The stages within Phase 2 keep to the
explanatory mixed methods ‘follow-up explanation model’ through the adoption of quantitative
processes followed by the employment of qualitative techniques for improved explanation and
outcomes. An overview of the Phase 2 research method and design is demonstrated in Figure
3-6.
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End use water consumption design & technology
Industry experts & past literature
INPUT RESEARCH ACTIVITY OUTPUT
Residential end use study design: data requirements & technology
Research size & potential participants
Determine sample size, research region & pilot group
Develop participant recruitment material
Design of recruitment letters, incentives & consent form
Literature, past research & industry experts
Consenting sample obtainedRecruitment approach
Stage 2a: End use water consumption design
Stage 2b: Obtain consenting sample
End use consumption monitoring process
Residential end use study design
Raw end use water consumption data
Monitoring end use water consumption
Industry experts & past literature
Stage 2c: Potable end use water consumption data
Detailed water audit & interview questions
Water audit & interview design
Qualitative data of water use fixtures & behaviours
Qualitative data collection
Literature, past research & academic experts
Water use validationDetermine efficiency, fixture use
& behavioural profile
Stage 2d: Stock survey & water use behaviour audit
Data set of residential end use water consumption
Trace Wizard© analysis of end use data
End use water consumption profiles
Validation of end use breakdown & calculations
Tuition from industry expert, fixture & water use behaviours
Stage 2e: Potable end use water consumption
Survey quesionnaireQuestionnaire development
Data set from the survey of residential water consumers
Questionnaire survey
Literature and academic/industry expert review
Descriptive resultsDescriptive data analysis
Stage 2f: Questionnaire development, distribution & analysis
Validated resultsMeasurement model analysis
(CFA & cluster analysis)
Consenting sample obtainedParticipant recruitment & data
collection design
Installation of shower monitors Purchase shower monitor units &
determine installation process
Academic & industry literature & research sample
Post shower monitor end use water consumption
Collect end use data, statistical analysis (descriptive & t-test)
Stage 2g: Educational shower monitor device
Phase 2: Water End Use & Demand Management
Figure 3-6 Phase 2 research activities and output
Figure 3-6 details the seven quantitative and qualitative stages which occurred during Phase 2 of
the research. Each stage of Phase 2 resulted in outcomes relevant for subsequent stages in the
design; all stages are discussed in detail in the following sections.
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3.3.1 Stage 2a: End use water consumption design
The first stage of Phase 2 was the design of the end use measurement study. Figure 3-7
demonstrates the inputs, research activities and outputs for Stage 2a.
Figure 3-7 Stage 2a: End use water consumption design
The main components of this stage were to determine the data type and technology necessary to
collect end use water consumption. The research objectives of this study stipulate the need for
high resolution water end use consumption data to assist in determining all individual events
within homes such as showering, irrigation or leakage. The most relevant example of a national
end use water consumption study was carried out by Yarra Valley Water in Melbourne in 2005.
Roberts (2005) utilised data measurement technology which enabled the reading of volumes of
water as small as 0.014 litres. An investigation into water metering and data logger technology
was carried out considering this study as well as other domestic end use studies completed
throughout the world (Mayer and DeOreo, 1999; Loh and Coghlan, 2003; Mayer et al., 2004;
Heinrich, 2007; Mead, 2008).
Water meter and data logger technology assessment
The water meter utilised by Roberts (2005) remained the highest resolution water meter
available on the market. Other products considered included the Pryde SPX-075 low flow meter
and high resolution meters sourced directly through Manuflo. Consequently an Actaris CT5
water meter, pulse rate 2 pulses/litre or 0.5 litres/pulse was purchased through Actaris and
modified by Manuflo to result in the CT5-S water meter which pulsed at rate of 72.5 pulses/litre
or 0.014 litres/pulse. Research was also undertaken to determine the latest developments in data
logging technology. Products considered included the SBS Systems Halytech Spider with
Waveflows, E-State Automation Waveflow wireless meter monitors and Moneta R-Series data
loggers. Mayer (2005) made use of a USA technology, the F.S. Brainard's Meter-Master© Flow
Data Loggers and software.
Again, Roberts (2005) work was utilised as a benchmark to determine the most appropriate
Australian data logging technology. Roberts (2005) utilised the Monatec Data Monita XT data
loggers but the failure of some of these devices resulted in the use of the Monita D-Series data
logger which had similar specifications; this Monita D data logger was still one of the best
products on the market. The Monita D series logger was selected as it was capable of recording
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up to 2 million end use data points and allowed for the input of four (4) different channels and
had a battery life of ten (10) years. Such a large memory capacity was required as data was to be
downloaded manually after each logging period and logging was occurring in dual reticulated
areas which meant the input of two channels from the potable and recycled water meters. While
technology had developed to enable remote readings of data (through GSM or other networks)
the significantly increased cost per data logging unit, the cost of transmitting data back to a
central hub, the range at which homes were located from each other or from the central hub and
power supply all lead to the decision to undertake manual downloads. Since the initiation of the
study in 2007, the, cost and technology of remotely read data loggers has significantly improved
the feasibility of remote data downloads.
End use analysis technology
The end use analysis program utilised by previous studies including those carried out in
Melbourne, Perth, Toowoomba, Tampa and (USA) across twelve regions the USA, was Trace
Wizard©. This software was developed by AquaCraft in the USA specifically to undertake this
analysis activity. The Trace Wizard© software was selected as the most appropriate analysis
tool due to its suitability for Windows environments, the ease of undertaking flow trace analysis
and the reasonable price for the software package. The Trace Wizard© program was specifically
modified by AquaCraft Inc® for this study to enable the software package to receive data from
the four channels of the Monita D series loggers. Giurco et al. (2008a) recommend Trace
Wizard© as the principal end use water consumption analysis tool.
Logging period
The logging period and time steps of earlier end use studies have varied. Roberts (2005) logged
at 5 second intervals over two week periods while Mayer and DeOreo (1999) and Mayer et al.
(2004) logged at a 10 second intervals. Mayer and DeOreo (1999) state that the 10 second time
interval results in accurate data to ‘quantify and categorise’ individual end uses. Hence, a 10
second interval was selected for the end use study due to considerations of data storage and
management (note: decreasing the interval from 10 – 5 seconds doubles the data points).
Logging periods were selected to occur in winter and summer with two week periods of data for
analysis. Additional data was to be recovered for reference or further investigation if time
permitted.
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3.3.2 Stage 2b: Obtain consenting sample
Stage 2b of Phase 2 was to determine the sample size and to obtain a consenting sample with
which to carryout the research. Figure 3-8 demonstrates the inputs, research activities and
outputs of Stage 2b.
Figure 3-8 Stage 2b: Obtain consenting sample
Literature, past research and industry experts were all consulted to assist in determining the
sample size, the research region, recruitment material and the approach to recruit participants.
Sample size
To ensure the research findings are representative of a population, an appropriate sample must
be selected (Howell, 2004). For statistical significance and appropriate representativeness of end
use for the Gold Coast city, a large sample size of households would be required. This is due to
the variation in water consumption which can be exhibited by a large population. The
population of the Gold Coast at commencement of the research was 485,000 or approximately
177,000 households. A representative sample from this population would be 266 households
when assuming a confidence level of 95% and a confidence interval of six (6) (three (3) steps
from either side of the mean which is generally the lowest acceptable confidence interval)
(Howell, 2004). Decreasing the confidence interval and increasing the confidence level both,
increase the sample size. This is due to the increase in precision and accuracy with which the
results can be applied to the total population.
For end use sampling in this research, a total of eight (8) end uses will be determined (clothes
washer, shower, tap, toilet, dishwasher, bathtub, irrigation and leak) as well as a total
consumption figure. Giurco et al. (2008a) specify that when determining the required sample
size for an end use study it is important to understand the mean and standard deviation (SD) of
the various end use results. Field (2005), states that SD is a measure of how well the mean
represents the observed data. Data with smaller SDs more adequately represent the sample due
to less dispersion of the data points around the mean. This is reiterated by Giurco et al. (2008a)
who specify that if the researcher wants to discern six (6) end uses with a small and precise SD
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of 10L (compared to average of 143L) the sample size would be as high as 1,200. If the
precision can be reduced to moderate (20L) or lower (30L) precision then samples sizes of 300
and 130 are adequate respectively.
Some end uses are more variable in volumetric use and hence, have a higher SD values. When
examining winter 2008 end use data from this research, dishwashing and toilet flushing have SD
values under 10L due to the relative consistency in volumes as stipulated by the efficiency of
the device. Other end use SDs are more variable with tap use SD being 12.51 L/p/d while,
irrigation possessed the highest SD of 35.37 L/p/d with a mean of 18.58 L/p/d. The most precise
end use is dishwashing with a mean of 2.22 L/p/d and SD of 2.4 L/p/d. With a sample size of
151 households one can be 95% certain that the true population mean falls within the range of
1.84 to 2.6 L/p/d (confidence level of 0.38). If this low confidence interval was adopted to
determine the initial sample size for Gold Coast city (n=177,000 homes) more than 48,000
homes would be required. A highly variable end use is irrigation with a mean of 18.58 L/p/d and
a SD of 35.37 L/p/d. With a sample size of 151, it is 95% certain that the true population mean
falls within the range of 12.94 to 24.22 L/p/d for irrigation (confidence interval of 5.64). If this
confidence interval was acceptable, with irrigation being the most unpredictable and variable
end use, a sample size of 301 homes would be representative of the Gold Coast residential
population of 177,000 homes. The confidence interval of irrigation is just under the largest
acceptable confidence interval of 6. As irrigation was found to be the most variable and
unpredictable end use, an initial sample size between 301 and 266 homes for the Gold Coast
should accurately represent the usage of the Gold Coast population. This is still a large sample
size especially when considering the cost and feasibility of recruiting, sampling and analysing
this much end use data hence, further research was undertaken to establish sample sizes used in
earlier end use studies.
When undertaking end use sampling the accuracy and precision of results must be considered
alongside cost due to the average household cost to collect end use data being approximately
$1500 (Giurco et al., 2008a). Earlier end use studies have ranged in sizes from ten to 1188
homes across twelve (12) municipal areas (Mayer and DeOreo, 1999; Mead, 2008). Roberts
(2005) and Mayer and DeOreo (1999) both determined that a sample size of 100 households per
water utility service area was sufficient and representative for end uses within homes based on
their resulting means and standard deviations. Further discussions with end use expert Peter
Mayer (2007), reiterated that a sample size of 100 households was sufficient to undertake end
use water consumption analysis in a region. Consideration on the need for the representativeness
of the end use data for the Gold Coast region, the cost to carry out end use analysis and the
feasibility of obtaining a sample size between 301 and 266 homes, resulted in the decision on a
smaller sample size of 200. While this sample size is lower than the original statistically
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representative value required (n=266) and lower than that required to meet the confidence
interval of the most variable end use, irrigation (n=301), it is higher than that specified by end
use experts and fits within the moderate precision of standard deviation for end use data
collection (Giurco et al., 2008a). Moreover, a sample size of 200 is feasible in terms of cost and
is also a manageable size for participant recruitment, data collection and analysis.
Research region
The primary research region was Pimpama Coomera due to the objective of undertaking
analysis of end use water consumption in a dual reticulated area. Because of this objective, a
stratified approach was utilised which resulted in the selection of three (3) district metered
developments within Pimpama Coomera. Socio-economic status was a primary consideration
for these areas to ensure the sample included a range of household incomes. The demographic
characteristics of Pimpama Coomera were investigated through ABS 2006 statistics. Pimpama
Coomera local area demographics were quite unique due to the high number of renters with
high incomes, which differed in comparison to the wider Gold Coast characteristics. PC also
possessed a higher number of people per household and a high number of parents with young
children which skews the trend toward a younger population (see Appendix A).
The control or comparison group, not within the dual reticulated region, was determined
through a comparison of 2006 ABS demographic statistics between Pimpama Coomera and
other local areas within the Gold Coast (Appendix A shows details). Mudgeeraba was selected
as this local area that demonstrated similar demographic characteristics to Pimpama Coomera.
Within Mudgeeraba, a district metered area that had been developed in the last five (5) years
was selected to ensure the water use fixtures and fittings were relatively comparable.
Design of participant recruitment material
The recruitment of participants is a challenging activity hence the material used to undertake
this process should be professionally and meticulously prepared. For the purpose of this study
an introductory letter, a consent form and a frequently asked questions factsheet were
developed. An incentive in the form of a $20 voucher was also offered along with a chance to
win a major prize valued at $1000. Brase et al. (2006) specify that the best participant
recruitment rates were obtained when incentives or payments were given for participation.
Study recruitment material was developed through the examination of similar recruitment
information for earlier research investigations and with the professional assistance of the
community engagement team at Gold Coast Water. This team added significant value through
their extensive experience in communicating with the Gold Coast community and their
understanding of the community’s response to such research and distribution materials. The
Chapter 3: Research Method and Design
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participant recruitment letter outlined the details of the research and activities that would be
undertaken as part of the investigation, Appendix B presents the letter. The frequently asked
questions factsheet, detailed in Appendix C, provided more specific information on the
equipment used, where and what the data would be used for, information required from
participants as well as the protection of this information. The consent form was the contract
between the participant and the researchers that reiterated all the activities to be undertaken
along with verification that all information was condoned by the University Ethics Committee
(see Appendix D). Obtaining permission from the participants and university were paramount
for the collection and protection of data. Completed participant recruitment material enabled
commencement of the recruitment process.
Participant recruitment approach
The participant recruitment design was a purposely structured approach. Participant recruitment
consisted of the mail distribution of all material to households (Appendix A-D) followed up by
the door knocking of all homes which had received this research information. A verbal approach
for door knocking was developed and utilised throughout the recruitment period. Households
that received the information were visited until the researcher met face-to-face with a resident to
determine their interest in voluntary participation. The information that was distributed to
households was carried by door-knockers along with consent forms and incentives. A gift
voucher of $20 and a gift bag from GCW was presented to each participant upon completion of
the consent form. When households consented to be involved in the research, a few general
questions were asked which included the estimated length of time residing in the household,
ownership status, the number of people in the home and a contact phone number. This
information assisted to determine if the household would be a full or reserve research
participant. Reserve participants were those that indicated that they would not be in the region
for longer than one year. Responses from householders differed significantly with the most
frequent responses listed below:
Household had received and read the information about the research and signed up
without hesitation or handed over a completed consent form;
Household had received the information but not read it and signed up after further
discussions with the door-knocker;
Household had received the information and had read through it but was not interested
in participating even after further discussions with the door-knocker; and
Household refused to participate or discuss with the door-knocker as they were not
interested in research.
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Overall, householders in all regions were very friendly and receptive to door-knockers. It should
be noted that on certain participant recruitment days some households had as many as five door-
knockers from different companies which was challenging for recruitment researchers. The next
process was the installation of equipment for consenting households and monitoring end use
water consumption.
3.3.3 Stage 2c: Potable end use water consumption data
Stage 2c involved testing the end use consumption data collection process through the design of
the installation and monitoring process and the obtainment of actual end use water consumption
data. The processes included in this stage are detailed in Figure 3-9.
Figure 3-9 Stage 2c: Potable end use water consumption data acquisition testing
Figure 3-9 demonstrates the testing and verification process for the installation of equipment
and the collection and analysis of end use water consumption data. Particulars on the end use
study design are discussed.
Equipment and monitoring
The installation of high resolution water meters was carried out through GCWs water meter
exchange program which involved the distribution of a notification letter to residents and
subsequent water meter exchange. High resolution data loggers were installed by the research
team through individual visits to each home and manual installation of data loggers in water
meter boxes. As mentioned, each data logger was able to receive up to four (4) inputs hence
only one (1) data logger was required for both single and dual reticulated homes. Testing of the
end use water consumption monitoring design occurred through the verification that each water
meter and connected data logger was actually recording end use data i.e. data was recorded from
households. This testing process resulted in the determination that end use data was not being
obtained for some households, with investigations determining the main cause as faulty reed
switches in the water meters as well as water intrusion in data loggers. Negotiations with
equipment manufactures assisted in resolving these issues although water intrusion remained a
serious issue throughout the study.
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Data collection and analysis
Collection and analysis of end use water consumption data involves numerous steps. Firstly raw
end use data is downloaded through the data logger ‘Command’ software. This data is then
processed into readable Microsoft ‘txt’ files which can be directly uploaded into the Trace
Wizard© analysis program. This process results in the obtainment of flow-based water
consumption data for each household within the study. The Trace Wizard© templates provided
with the program were developed with data from the USA hence, the software’s built-in
automated selection of different end uses within homes was not compatible when applied to
Australian fixtures. For example, Mayer and DeOreo (1999) noted that the average toilet flush
from end use investigations in the USA is 3.48 gallons (13.17 litres) per flush. In Australia,
toilet flushing in new houses ranges from 3 to 9 litres per flush hence, to utilise and verify the
end uses within each Gold Coast household additional information on the water use fixtures and
water use behaviours of residents was required. A detailed diagram outlining the end use data
downloading procedure is presented in Figure 3-10.
Connect.lnk
Trace Wizard Pro.lnk
Processed end use data
Uploaded end use water consumption
dataRaw end use data
0402EA010A0000002203080A1C011E080F000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000
011413,28/10/08 16:12:58,10,0,0,0,0011413,28/10/08 16:13:08,10,35,146,0,0011413,28/10/08 16:13:18,10,1,169,0,0011413,28/10/08 16:13:28,10,0,125,0,0011413,28/10/08 16:13:38,10,0,51,0,0011413,28/10/08 16:13:48,10,0,20,0,0011413,28/10/08 16:13:58,10,0,7,0,0011413,28/10/08 16:14:08,10,0,4,0,0011413,28/10/08 16:14:18,10,1,3,0,0
Water Meter: CTS-5
Data Logger:
Monita D series
Equipment
Downloading Data
Raw end use data process software
End use analysis software
Figure 3-10 End use data downloading procedure
As demonstrated in Figure 3-10, the end use data downloading procedure results in non-
categorised end use flow traces. In order to accurately categorise end uses a stock inventory and
water audit was undertaken to reveal the fixtures/appliances and water consumption behaviours
within individual households.
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3.3.4 Stage 2d: Stock survey and water use behaviour audit
Stage 2d, the stock survey and water use behaviour audit, was the principal qualitative
procedure in the research methodology. The stock survey and water use behaviour audit, was
undertaken with almost every household to determine basic demographic information, the water
use stock present within the home, the efficiency of water use stock, and the water use activities
and behaviours of residents. Initially, it was thought that only a few households would need to
be audited but once the complexity of uses and behaviours within each home was realised it was
determined that the application of this qualitative process to the entire sample would provide the
most accurate water end use information. This stage was pertinent to assist in the analysis and
verification of end use water consumption within each household. Figure 3-11 details the
processes of Stage 2d.
Figure 3-11 Stage 2d: Stock survey and water use behaviour audit
Figure 3-11 demonstrates that literature, past research and academic experts were consulted to
assist in the development of the water audit and interview design. Being a qualitative process,
open ended questions were primarily used as discussion points for the researcher with the
resident. Appendix E shows the water audit in its entirety. The water audit consisted of
determining some basic demographic information for the household, determining the water use
fixtures and fittings within the household and asking for residents to explain how, when and the
duration of water fixture use and associated behaviours. This process enabled the establishment
of the current water usage stock within the community and allowed for the understanding of
how and when residents consumed water within the home.
Collection of this qualitative data occurred through visits to each of the homes at a pre-
determined time convenient for the resident. Researchers talked through each question with the
residents and walked around the home looking at and recording water stock and enquiring about
the use of each device. Residents were asked to elaborate on any interesting comments or
thoughts on water use in their home or in general. This process resulted in a qualitative database
of water use fixtures, fittings and behaviours within the sample. Data collected through the
water audit was used in conjunction with the WELS website to determine the water
Chapter 3: Research Method and Design
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consumption and efficiency of the devices that are easily determined i.e. clothes washers,
showers, dishwashers and some toilets. Qualitative water use activities and behaviours outlined
by residents were used to inform and develop water usage profiles for each home. For example,
a resident stated:
“I use my clothes washer on the weekend and do at least two loads” and “I generally
shower for about seven minutes every night”.
Such statements were used in collaboration with the average consumption listed for the recorded
clothes washer model and shower rose to assist in determining the household water use profile
and efficiency of devices. The data from this qualitative process was used to analyse the end use
water consumption in each of the households. This data was imperative in the determination of
fixtures and fittings within homes, the relative efficiency of fixtures, the perceived time of day
and duration of use, and the water usage patterns and behaviours unique to each household. This
data enabled the development of Trace Wizard© templates for each home, was used for
determining the efficiency of fixtures and to carryout end use water consumption data analysis.
3.3.5 Stage 2e: Potable end use water consumption
Stage 2e of the research method was the actual analysis of end use water consumption data
through the integration of collected end use water consumption data and the stock survey and
water use behaviour audit. Stage 2c was the collection of end use water consumption data and
resulted in the determination that a qualitative process was required to assist in understanding
this data. Stage 2d was the collection of water fixture and usage behaviours pertinent to the
establishment of end use water consumption profiles for each household. Stage 2e collectively
unified the earlier research stages to enable data analysis using the Trace Wizard© software to
result in a validated data set of residential end use water consumption data for the sampled
households (Figure 3-12).
Figure 3-12 Stage 2e: Potable end use water consumption
The quantitative data analysis procedure shown in Figure 3-12 included visual inspection of the
data, checking for consumption trends and representation of results in tables and figures. Peter
Mayer, the developer of Trace Wizard© and end use analysis expert also provided training on
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the software. Once the data set or template was established for each home, a validation process
occurred through the revisiting of water audit information and a cross-check with bulk meter
water consumption data from GCWs billing system. This assisted to ensure that daily and
weekly end use water consumption data was on par with the households bulk metered water
consumption data. Stage 2e resulted in end use water consumption data for each household in
the research sample to meet one of the research objectives. Further stages were carried out to
meet additional research objectives.
3.3.6 Stage 2f: Questionnaire development, distribution and analysis
Stage 2f included the development and execution of a questionnaire survey to assist in
determining the effect of socio-demographics, perceptions, attitudes and understanding on end
use water consumption behaviour. Questionnaires consist of pre-formulated written questions
which respondents answer following stipulated protocols (Sekaran, 2003). Surveys aid in
describing trends; in determining individual opinions and knowledge; in the identification of
beliefs and attitudes; the establishment of characteristics and expectations; and, they can
evaluate the effectiveness of programs (Neuman, 2003; Creswell and Plano Clark, 2007).
Researchers utilise surveys as a deductive approach to measure variables, to statistically
examine their effect and to rule out alternative explanations (Neuman, 2003). Surveys ensure
empirical measurement and data analysis results from a theoretical or applied research problem
(Neuman, 2003). The survey design utilised for this research was in the form of a questionnaire
survey with closed and open-ended questions, which was designed for participants to complete
and return to the researcher. It is important to note that only one questionnaire survey was
completed per household. The head of each household was requested to convene a meeting with
other residents, and consultatively respond to the questionnaire items, thus providing a response
which was representative of the group. In cases where members could not attend or were young
children, they were requested to provide a perceived rating which reflects their perception of the
household’s overall attitude to the listed items.
Qualitative or open-ended questions in survey research or questionnaires allows respondents to
express their individual beliefs and feelings and to clarify their responses to quantitative
questions (Neuman, 2003). They allow the researcher to determine what is important to the
respondent, how and what they are thinking and also results in answers to questions that the
research may not have thought of previously (Neuman, 2003). Mixing both open- and closed-
ended questions changes the pace of the questionnaire and also provides a richness of data
(Neuman, 2003). Some notable disadvantages of open-ended questions are that analysis and
comparison can become very difficult, different degrees of responses are given and a greater
amount of time is required by residents who may be intimidated by questions (Neuman, 2003).
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Details on the process of questionnaire development, execution and analysis are presented in
Figure 3-13.
Figure 3-13 Stage 2f: Questionnaire development, distribution and analysis
The design of the questionnaire survey occurred through a review of related survey literature
and followed the survey development guidelines authored by Dillman (2000). The draft survey
was revised through an academic and industry expert-review process whereby four university
researchers and two industry experts refined the questions and checked the theoretical
constructs. The final survey can be viewed in Appendix F. The purpose of the questionnaire
survey was to test the relationships between end use water consumption (dependent variable)
and other variables such as demographics; awareness and use of water efficient devices;
preference of water source for water use activities; understanding of water consumption within
homes; attitudes towards the environment, water and water efficient devices; and attitudes and
understanding of dual reticulation (independent variables). Figure 3-14 demonstrates a
diagrammatic overview of the variables developed for testing in the questionnaire survey. The
variables tested through the experimental research (end use water consumption data) included;
educational awareness devices, household understanding of water efficiency, attitudes towards
the environment and water, and demographics. The questionnaire investigation assisted in
determining the causal relationships between the experimental data and questionnaire survey
data.
A five-point Likert-type measurement scale was adopted for the respondents’ rating of
attitudinal items, with 1 representing strongly disagree and 5 representing strongly agree.
Earlier survey investigations have determined that a five-point scale is comparable with a seven
or nine-point scale and that increasing the rating scale will not improve the dependability of
ratings (Neuman, 2003; Creswell, 2008).
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Figure 3-14 Diagram of relationships between dependent and independent questionnaire survey variables
Questionnaire distribution and collection
The questionnaire survey was distributed via postal mail to all households, for which
researchers had analysed end use water consumption data for (n=151). A letter describing the
purpose of the questionnaire and stipulating the receipt of a $20 gift voucher upon the return of
a completed questionnaire was also included (see Appendix G). Of the 206 surveys sent, a total
of 151 completed responses were returned which equates to a response rate of 73.3%. Such a
high response rate was achieved through the inclusion of an incentive, the household’s prior
signed consent to be a part of a number of research activities, and through follow-up phone calls
made by the research team to encourage residents to return their completed questionnaire.
Questionnaire survey data analysis
The objective of undertaking a questionnaire survey was to ascertain demographic information,
determine awareness of numerous water related topics and to establish the use of water efficient
devices. The survey also assisted to understand perceptions/attitudes of respondents in relation
to water efficiency and the environment. The determination of these elements assisted in
revealing the impact of the independent variables on end use water consumption behaviour.
Multivariate statistics were utilised to quantitatively analyse data collection in the questionnaire
survey. Such techniques were considered suitable as they provided an analysis method for the
complicated data set which included numerous independent variables (Tabachnick and Fidell,
2007).
Chapter 3: Research Method and Design
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Questionnaire survey data was transformed into a readable form through data entry into the
statistical analysis program AMOS (version 17.0). Initially, descriptive data analysis was
undertaken to determine the characteristics of the sample. Analysis included the examination of
respondent profiles, as well as data screening through assessing means, normality, frequencies
and standard deviations. Details and results of descriptive analyses are presented in Chapter 4.
Following this, ‘Cronbach’s alpha’ was employed to measure scale reliability which indicated
how consistent responses were across the measured items. Factor analysis was also adopted to
assess the validity of the measurement scale using the ‘Confirmatory Factor Analysis (Giurco et
al.) technique. CFA was employed to assess constructs validity and unidimensionality. In
essence, CFA is a way of testing how well a priori factor structure and its respective pattern of
loadings match the actual data (Hair et al., 2006). Cluster analysis was utilised and is described
by Hair et al (2006), as an exploratory data analysis tool for solving classification problems. The
purpose of cluster analysis is to categorise cases into groups or clusters so that each case is very
similar to others in its clusters. This analysis technique was adopted to determine if distinct
groups were evident in the research sample. Detailed discussion and results of statistical
investigations are presented in Chapters 6, 8 and 9.
3.3.7 Stage 2g: Educational shower monitor device
Stage 2g involved a quantitative experimental investigation to determine the end use water
consumption savings attributed to an educational shower monitor device. Experimental research
is commonly applied across the sciences as a quantitative and ‘pure’ form of positivist research
(Neuman, 2003, pp 440). ‘Positivist’ here denotes the scientific method approach for testing a
hypothesis. Experiments aim to test an idea and to determine the influences on an outcome or
dependent variable by keeping a group in its original state and altering another group to
compare the differences (Creswell, 2008). Neuman (2003) delineates that experimental research
follows three steps, being:
1. Begin the experiment with a hypothesis;
2. Modify something in the experiment; and
3. Compare the outcomes pre and post modification.
An experimental research technique is the ‘strongest for testing causal relationships because the
three conditions for causality (temporal scale, association, and not alternative explanations) are
clearly met in experimental designs’ (Neuman, 2003, pp. 441). Experimental research also has
practical advantages in comparison to other techniques and weaknesses such as basic logic,
narrow scope and practical restraints which need to be overcome through the application of
other research techniques (Creswell, 2005). Establishing possible cause and effect between the
independent and dependent variables is the main purpose of experimental research (Neuman,
2003). Comparing, determining and measuring the differences between the independent and
Domestic End Use Investigation: WDM and Dual Reticulation, R.M. Willis (2010)
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dependent tested variables, allows the researcher to establish strong and weak relationships
between the variables (Neuman, 2003). For the purpose of this stage of the research,
manipulation of one independent variable occurred true to the experimental design framework
(Punch, 2000). Figure 3-15 demonstrates the design for the experimental investigation.
Figure 3-15 Stage 2g: Shower monitor investigation
The purpose of this experiment was to determine the effect on end use shower behaviour
including total consumption volumes, shower duration and flow rate pre and post the
installation of the educational shower monitor device. An important aspect of experimental
research is to determine the statistical significance and influence on the dependent variable, end
use water consumption, by the manipulation of the independent variable namely, the shower
monitor (Neuman, 2003). Statistical techniques applied for this experiment included descriptive
statistics and the application of the independent sample t-test. Additional information on the
data analysis techniques and the outcome of this quantitative experiment are illustrated in
Chapter 7.
3.4 Phase 3: Dual Reticulated Recycled Water
Phase 3 involved the development of a predictive recycled water uptake model, the monitoring
of end use recycled water post implementation and the validation of a model for recycled water
end use consumption for dual reticulated regions. Figure 3-16 details the three stages of Phase 3.
Phase 3 is a quantitative research phase with the application of an experimental design to
determine the water savings attributed to the introduction of recycled water. A detailed
overview of the research method and design for Phase 3 is demonstrated in Figure 3-16. Each
stage in Phase 3 involved numerous processes to achieve the stated objectives of the design, as
described in the below sections.
3.4.1 Stage 3a: Predictive dual reticulated recycled water uptake model
The purpose of Stage 3a was to develop a predictive model for recycled water uptake in dual
reticulated regions. End use water consumption data was collected in Phase 2 of the research
Chapter 3: Research Method and Design
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pre-implementation of recycled water distribution to households in the Pimpama Coomera
region. This data, questionnaire survey data, uptake in other dual reticulated regions and
influencing factors such as water restrictions, climate, price, lot size and marketing were all
considered in the development of the predictive model as demonstrated in Figure 3-17. This
study adopted a possibility/fuzzy set theory approach due to the inherent fuzziness of future
predictions of water use for a new supply source (i.e. A+ recycled water) in a new context (e.g.
Gold Coast, Queensland, Australia). This theory was adopted as the necessary data sets required
for predictive assessments, such as probability theory, Monte Carlo simulation and sensitivity
analysis, were not available.
Literature on dual reticulated consumption
INPUT RESEARCH ACTIVITY OUTPUT
Stage 3a: Predictive dual reticulated recycled water uptake model
Stage 3b: Dual reticulated recycled water end use consumption data collection and analysis
Verification of recycled water end use consumption in dual
reticulation region
Compare potable and dual reticulated recycled water end
use
Validation of potable end use water savings in a dual
reticulated recycled water region
Comparative analysis of PC dual reticulation demand forecast
model
End use water consumption profiles for recycled water
Stage 3c: Dual reticulated recycled water end use consumption
Phase 3: Dual Reticulated Recycled Water
End use water consumption data (single vs. dual) & bulk
billing data
Baseline end use water consumption for dual reticulaton
Validation of end use breakdown for dual vs. single reticulated
Comparison of usage between schemes
Validation of historical uptake rates of recycled water
Other regions end use water consumption data
Comparison of end usage between investigations
Determination of approximate irrigation as percentage of
consumption
Water restriction data Determination of influence on
consumptionInfluence of restrictions
Survey dataAnalysis of outdoor water use
activities and preferential water source
Preferential influence on water consumption type
Literature and data on recycled water pricing, climate,
lot size & marketing
Influence of variables on water consumption
Final prediction of recycled water uptake in dual reticulated region
Data set of residential recycled end use water consumption
Trace Wizard© analysis of end use data with water audit
End use water consumption profiles for recycled water
Validation of end use breakdown & calculations
End use templates, data & processes from Phase 2
Raw recycled end use water consumption data
Monitoring recycled end use water consumption
End use diurnal patterns for recycled & potable water use
Development of diurnal pattern tool for end use water
consumption data
Figure 3-16 Phase 3: Detailed overview of research activities and output
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Applying the possibility/fuzzy set theory, the influence of all the obtained data was determined
by an expert panel to result in a lower value, most likely value and upper value of recycled
water consumption in the dual reticulated Pimpama Coomera region post-distribution of
recycled water. Further details on the method, analysis and results associated with this stage of
the study are presented in Chapter 8.
Figure 3-17 Stage 3a: Predictive dual reticulated recycled water uptake model
3.4.2 Stage 3b: Dual reticulated recycled end use data collection and analysis
Stage 3b involved the utilisation of an experimental design to determine actual recycled end use
water consumption in a dual reticulated region pre and post distribution of recycled water Figure
3-18.
Figure 3-18 Stage 3b: Dual reticulated recycled end use water consumption data collection and analysis
Chapter 3: Research Method and Design
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The experimental design used to establish the end use potable water savings attributed to the
introduction of recycled water via dual reticulation is displayed in Figure 3-18. Common to all
experimental designs, a before and after test was carried out to determine the change attributed
to the independent variable.
End use water consumption data obtained in Phase 2 of the research method was adopted as the
baseline information as this data was collected before recycled water was distributed through
the dual reticulation infrastructure. End use water consumption was collected post
implementation of recycled water to the dual reticulated region with the Mudgeeraba region
remaining as a control group. End use analysis and validation was undertaken using the same
approach as detailed in Phase 2. This process resulted in the obtainment of end use water
consumption data post implementation of recycled water in the dual reticulated recycled water
region. Further detail on the process and results of this design are presented in Chapter 9.
3.4.3 Stage 3c: Dual reticulated recycled water end use consumption
The final stage of the research method was the measurement of end use water consumption data
post-commissioning of recycled water in the PC dual reticulated areas. The purpose of Stage 3c
was to combine the data obtained from Stage 3b into the predictive model developed in Stage 3a
while adopting a developed diurnal pattern tool to finalise a usable end use model for dual
reticulated recycled water regions. This stage also allowed for the comparative assessment of
pre- versus post-commissioning end use water consumption data. Details of the design process
are demonstrated in Figure 3-19.
Figure 3-19 Stage 3c: End use model for dual reticulated recycled water consumption
As illustrated in Figure 3-19, data from previous stages were utilised to assist in the validation
of end use water consumption for dual reticulated recycled water regions. Initially, a
comparison of end use water consumption data was undertaken against the single and dual
reticulated regions. This enabled the verification of recycled water end use consumption in the
PC region once recycled water was supplied.
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A comparative assessment was carried out to determine the differences between the recycled
water up-take predicted in the pre-commissioning phase (see Section 3.4.1) against the actual
post-commissioning recycled water consumption recorded. This involved analysis of end use
water consumption particularly for recycled water end uses (irrigation, toilet and leak) against
that predicted. This resulted in the verification of end use water consumption for the potable and
recycled water lines post-commissioning of recycled water to the PC region.
A diurnal pattern software tool was developed to assist in the collaboration and analysis of end
use water consumption data files (Trace Wizard©/MS Access). Tabulated data sourced through
the software can be grouped within user selected time periods from hourly (24 graph points)
through to five minute intervals (288 graph data points). This enables data collaboration and
display of various ranges of data as prescribed by the operator. The diurnal software also allows
for weekday and weekend comparison to determine the differences between these distinct time
periods. The development of the diurnal software enabled the determination of hourly diurnal
patterns of use, at an end use level, for single and dual reticulated water supply regions. Chapter
9 details further discussion on the methodology adopted and the results from Stage 3c analysis.
3.5 Chapter Summary
This chapter examined the overarching research design and each aspect of the explanatory
mixed methods approach adopted to satisfy the developed research objectives. The application
of both quantitative and qualitative methods was necessary to strengthen the research design and
to address all research objectives. Quantitative methods including: questionnaire surveys, stock
inventory surveys and field experiments were utilised to satisfy research objectives. The follow-
up explanations model adopted for this study was true to character with emphasis being placed
on quantitative methods with qualitative data utilised to enhance the understanding on the
collected quantitative data. As a final note, this chapter was intended to provide an overarching
view of the numerous research methods applied. Each refereed publication chapter also provides
a detailed description on the specific research methods applied and the associated statistical
techniques adopted (e.g. factor analysis, cluster analysis, t-tests etc.). The following Chapter 4 is
dedicated to detailing the situational context in which the research (i.e. region, environmental
conditions, etc.) was undertaken and to describe in detail the research sample characteristics and
the end use data results from throughout the study.
3.6 References
Brase, G. L., Fiddick, L. & Harries, C. (2006) Participant recruitment methods and statistical reasoning performance. Journal of Experimental Psychology, 59:5, pp. 965-976.
Chapter 3: Research Method and Design
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Brewer, J. & Hunter, A. (1989) Multimethod research: A synthesis of styles, Newbury Park, CA: Sage.
Creswell, J. W. (2005) Educational Research: planning, conducting, and evaluating quantitative and qualitative research, 2rd ed, New Jersey, Pearson Education, Inc.
Creswell, J. W. (2008) Educational Research: planning, conducting, and evaluating quantitative and qualitative research, 3rd ed, New Jersey, Pearson Education, Inc.
Creswell, J. W. & Plano Clark (2007) Designing and conducting mixed methods research, USA, Sage Publications, Inc.
Dillman, D. A. (2000) Mail and Internet Surveys: The Tailored Design Method, 2nd edn, John Wiley, New York.
Field, A. (2005) Discovering statistics using SPSS, 2nd edn, SAGE Publications, London.
Giurco, D., Carrard, N., McFallan, S., Nalbantoglu, M., Inman, M., Thornton, N. & White, S. (2008) Residential end-use measurement guidebook: a guide to study design, sampling and technology. Prepared by the Institute for Sustainable Futures, UTS and CSIRO for the Smart Water Fund, Victoria.
Hair, J. F., Black, W. C., Babin, B. J., Anderson, R. E. & Tatham, R. L. (2006) Multivariate Data Analysis, 6th edn, Pearson Prentice Hall, Upper Saddle River, N.J.
Heinrich, M. (2007) Water End Use and Efficiency Project (WEEP) - Final Report. BRANZ Study Report 159. Judgeford, New Zealand, Branz.
Howell, D. C. (2004) Fundamental Statistics for the Behavioural Sciences, Thompson Brookes/Cole, Belmont, CA.
Loh, M. & Coghlan, P. (2003) Domestic Water Use Study. Perth, Water Corporation.
Mayer, P. (2007) Discussions with Peter Mayer from AquaCraft on end use water consumption studies. IN WILLIS, R. (Ed.) Gold Coast, Australia.
Mayer, P., DeOreo, W., Towler, E., Martien, L. & Lewis, D. (2004) Tampa Water Department residential water conservation study: The impacts of high efficiency plumbing fixture retrofits in single-family homes. Aquacraft, Inc Water Engineering and Management, Tampa.
Mayer, P. W. & DeOreo, W. B. (1999) Residential End Uses of Water. Aquacraft, Inc. Water Engineering and Management, Boulder, CO.
Mead, N. (2008) Investigation of Domestic End Use. Faculty of Engineering & Surveying. The University of Southern Queensland, Toowoomba.
Miles, M. B. & Huberman, A. M. (1994) Qualitative data analysis: A sourcebook for new methods, (2nd ed.). Thousand Oaks, CA: Sage.
Morse, J. M. (1991) Approaches to qualitative - quantitative methodological triangulation. Nursing Research, 40, 120-123.
Neuman, W. L. (2003) Social Research Methods: Qualitative and Quantitative Approaches, USA, Pearson Education Inc.
Punch, K. F. (2000) Introduction to Social Research: Quantitative and Qualitative Approaches, London, Sage Publications Inc.
Domestic End Use Investigation: WDM and Dual Reticulation, R.M. Willis (2010)
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Roberts, P. (2005) Yarra Valley Water 2004 Residential End Use Measurement Study. Melbourne, Yarra Valley Water.
Sekaran, U. (2000) Research Methods for Business: A skill-building approach, USA, John Wiley & Sons Inc.
Sekaran, U. (2003) Research Method for Business: A Skill-Building Approach, 4th edn, Wiley, New York.
Tabachnick, B. G. & Fidell, L. S. (2007) Using Multivariate Statistics, 5th edn, Pearson Education Inc, Boston.
Vogt, W. P. (2007) Quantitative Research Methods for professionals, Illinois State University, Pearson.
Chapter 4: Situational Context and Descriptive Data Analysis
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Chapter 4
Situational Context and Descriptive Data
Analysis The purpose of this chapter is to present the research circumstances experienced over the duration of the
study including climatic conditions, water restriction regimes and supplied bulk water. Moreover, this
chapter provides a detailed description of the recruited research sample through discussions on the
distinct research areas, the number of participants involved in the various aspects of the research stages
and descriptive socio-demographic characteristics of the group. All end use water consumption data
collected throughout the research is presented with additional discussion. The chapter begins with
Section 4.1, which provides an overview of the research sample location, the sample participation in
various research stages (questionnaire survey, water audits) and presentation of the spatial layout of
homes in the various areas. Section 4.2 details the characteristics of the research areas through
descriptive statistics. Section 4.3 presents the climatic, water restrictions and water supply context within
which the research was carried out. Section 4.4 presents detailed information and discussion on the end
use water consumption data collected over the duration of the research.
4.1 Research Sample Group
The research sample group was obtained from three areas within the Pimpama Coomera (PC) dual
reticulated recycled water region and one area in the single reticulated Mudgeeraba region between
February and May 2008. Figure 4-1 illustrates the location of the four study areas within the context of
Gold Coast City. As seen, three of the four research areas fall within the Pimpama Coomera region,
while just one is located in the wider Gold Coast. The reason for the higher utilisation of dual reticulated
region participants was to meet the research objective of measuring end use water consumption in a dual
reticulated area. Further detail of each research area with participating households is presented in Figure
4-2.
As demonstrated in Figure 4-2, each research area has participants scattered throughout. Some areas have
clusters of households (i.e. Mudgeeraba) while others are more spaced throughout the entire area (i.e.
Crystal Creek). A total of 206 full participant households and 59 reserve participant households were
recruited across the PC and Mudgeeraba areas. Details of the number of participants in the four areas at
time of recruitment are presented in Table 4-1.
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Figure 4-1 Research areas for the Gold Coast Watersaver End Use study
Chapter 4: Situational Context and Descriptive Data Analysis
- 87 -
Figure 4-2 Research areas and participating households
Domestic End Use Investigation: WDM and Dual Reticulation, R.M. Willis (2010)
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Each of the full participants (206) was contacted by phone and asked to participate in a qualitative water
audit, as detailed in Chapter 3. A total of 160 (out of 206) water audits were undertaken from August to
November 2008, a take-up rate of 77.7%. Moreover, questionnaire surveys were distributed to each
recruited household in November 2008, with a total of 151 returned. This equates to a response rate of
73.3% for the total sample (n=206) or a response rate of 93.8% for those that participated in the water
audit (n=160). Table 4-1 details the rates of participation in the water audits and questionnaire surveys
for the study sample.
Table 4-1 Overview of research area and recruited participants
Research area No. of Full
Participants
No. of Reserve
Participants
No. of Water
Audits
No. of Surveys
Mudgeeraba 51 4 43 36
Cassia Park 51 21 41 42
Crystal Creek 52 16 37 38
Coomera Waters 52 18 39 35
Totals 206 59 160 151
Table 4-1 shows that at least one additional household was recruited in each research area. Generally, the
uptake and participation in the various consensual research activities, including the qualitative water
audit and the questionnaire survey, was high. The water audits were carried out three to six months after
recruitment ceased, while the survey was distributed in November 2008, six months after the final
participants had been recruited. This may be the reason for the slight drop in attrition rate between the
two data collection activities. Socio-demographic characteristics obtained from the questionnaire survey
are discussed in Section 4.2.
4.2 Research Sample Characteristics
Participating households were requested to complete a questionnaire survey developed to assist in
determining the socio-demographic characteristics and socioeconomic status of households. These
surveys also assisted in determining environmental and water conservation perceptions and attitudes of
consumers. The completed questionnaire surveys (n=151) were entered into Predictive Analytics
Software 18.0 (PASW formally SPSS), a statistical analysis program (SPSS, 2010). PASW 18.0 is a
popular data storage platform and statistical analysis software with researchers and businesses.
Descriptive statistical enquiries were carried out to determine the socio-demographic characteristic of the
research sample. Section 4.2.1 divulges the socio-demographic characteristics and details the
classification of socioeconomic status for each research area.
Chapter 4: Situational Context and Descriptive Data Analysis
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4.2.1 Socioeconomic status of areas
Socioeconomic status (SES) refers to the level of people’s social and economic position in society, which
can be measured through numerous social and economic indicators. Social indicators can include
education, employment, type of job, housing and health, while economic indicators can include income,
home ownership and asset level (Vyas and Kumaranayake, 2006; NSW DET, 2009). For the purpose of
this research SES was determined through the examination of the ownership status, education level of
household adults, and household income, family types along with employment statuses, which were
utilised to cross examine the average weekly income with employment type.
Table 4-2 Overview of research area and socioeconomic status indicators
Research area Socioeconomic classification
Total no. of Households
Average property size
(m2)
Average income
Education status
Mudgeeraba Lower Middle to Middle Class
36 646.8 AUD$1387 Mainly High School and Technical
Cassia Park Lower Middle to Middle Class
42 671.7 AUD$1730 Mainly High School and Technical
Crystal Creek Lower Middle to Middle Class
38 655.6 AUD$1606 Mainly Technical and Tertiary
Coomera Waters
Middle to Upper Middle Class
35 806.4 AUD$1987 Mainly Tertiary
151 695.1 AUD$1677
The four research regions included in the sample were predominately from the middle class range (i.e.
lower middle to upper middle class). Initially, the research sample was believed to contain lower to
higher SES groups, albeit descriptive statistics demonstrate that this is not the case and that all research
areas fall within middle class SES. As demonstrated in Table 4-2, the number of households that
responded to the survey in Mudgeeraba was 36. The average property size, obtained from GCW mapping
records, was 646.8m2. The income level in Mudgeeraba was the lowest recorded of the areas at $1387
per week. In contrast to this, Mudgeeraba contained the highest percentage of retired couples (17%) as
well as a high percentage of mature couples working part time (see Table 4-3). This high percentage of
retired and part-time working couples significantly decreased the average weekly income of the area. The
education status of the area was primarily high school and technical education, Table 4-3 provides
specific details. The combination of these socioeconomic indicators resulted in Mudgeeraba being rated
as a lower middle to middle class area.
As demonstrated in Table 4-2, the number of households that responded to the survey in Cassia Park was
42. The average property size, obtained from GCW mapping records, was 671.7m2. The income level in
Cassia Park was high at $1730 per week. The education status of the area was primarily high school and
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technical education, Table 4-3 provides specific details. The combination of these socioeconomic
indicators resulted in Cassia Park being rated as a lower middle to middle class area.
The number of households that responded to the survey in Crystal Creek was 38 (Table 4-2). The
average property size, obtained from GCW mapping records, was 655.6m2. The income level in Crystal
Creek was $1606 per week. The education status of the area was primarily technical and tertiary, Table
4-3 provides specific details. The combination of these socioeconomic indicators resulted in Crystal
Creek being rated as a lower middle to middle class area.
As illustrated in Table 4-2, the number of households that responded to the survey in Coomera Waters
was 35. The average property size, obtained from GCW mapping records, was 806.4m2. The income
level in Coomera Waters was the highest of all the research areas at $1987 per week. The education
status of the area was mostly tertiary, Table 4-3 provides specific details. The combination of these
socioeconomic indicators resulted in Coomera Waters being rated as middle to upper middle class SES
area. Section 4.2.2 presents detailed demographics of the total sample.
4.2.2 Descriptive statistic characteristics of the total research sample
Table 4-3 presents descriptive statistical information on the research sample as a whole (total sample),
the single and dual reticulated regions and each individual research area. The total research sample has
an average of 3.4 people per household with areas ranging across lower middle to upper middle class
socioeconomic status areas (see Section 4.2.1 for details). The total research sample contains 62%
owners (n=94) and 26% renters (n=39) with 12% (n=18) of the sample not responding to this question.
Family types ranged from single persons, couples, small and large families, families with borders and
share houses. The most common family type was small families with 43% of participating households
within this family characteristic type (Table 4-3). Large families were the second most frequent family
type within the sample with 15% or 23 households. Mature couples formed 11% of the total sample,
retired couples 7%, single and young couples 3% each and families with borders and share houses 2%
each. Only 14% did not note their family type. The most frequent education level of the total research
sample was high school education (30%), followed closely by technical education at 29%, and tertiary
the least frequent at 22%. Only 1% of the sample was educated to lower than high school level, while
18% did not divulge their education status (Table 4-3).
Chapter 4: Situational Context and Descriptive Data Analysis
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Table 4-3 Descriptive statistics of research regions
Total sample
(n=151)
Single Reticulated
Region (MU n=36)
Dual Reticulated Regions
(CP/CC/CW n=115)
Mudgeeraba
(n=36)
Cassia Park
(n=42)
Crystal Creek
(n=38)
Coomera Waters
(n=35)
Average no. of people in HH 3.4 2.6 3.7 2.6 3.8 3.6 3.6
Ownership status Total % Total % Total % Total % Total % Total % Total %
Rent 39 26 8 22 31 27 8 22 12 29 15 39 4 12
Own 94 62 25 70 69 60 25 70 26 62 17 45 26 74
No response 18 12 3 8 15 13 3 8 4 9 6 16 5 14
Family type
Single person 5 3 3 8 2 2 3 8 0 0 1 3 1 3
Young couple 5 3 1 3 4 3 1 3 1 2 2 5 1 3
Mature couple 17 11 5 14 12 10 5 14 3 7 7 18 2 6
Retired couple 10 7 6 17 4 4 6 17 2 5 2 5 0 0
Small family 65 43 13 36 52 45 13 36 19 45 12 32 21 60
Large family 23 15 1 3 22 19 1 3 12 29 6 16 4 11
Family with border 3 2 1 3 2 2 1 3 0 0 2 5 0 0
Share house 3 2 2 5 1 1 2 5 1 2 0 0 0 0
No response 20 14 4 11 16 14 4 11 4 10 6 16 6 17
Education status
Mainly lower than high school 2 1 0 0 2 2 0 0 0 0 2 5 0 0
Mainly high school 46 30 16 44 30 26 16 44 17 40 8 21 5 14
Mainly technical 43 29 9 25 34 30 9 25 15 36 10 26 9 26
Mainly tertiary 33 22 5 14 28 24 5 14 4 10 9 24 15 43
No response 27 18 6 17 21 18 6 17 6 14 9 24 6 17
Socioeconomic classification Lower Middle to
Upper Middle
Class
Lower Middle to Middle
Class
Lower Middle to Upper Middle
Class
Lower Middle to
Middle Class
Lower Middle to
Middle Class
Lower Middle to
Middle Class
Middle to Upper
Middle Class
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4.2.3 Descriptive statistic characteristics of individual research areas
Mudgeeraba (MU), Cassia Park (CP), Crystal Creek (CC) and Coomera Waters (CW) were
selected as research sample target areas. Details of demographic variations between the areas
are presented in Table 4-3. The socioeconomic status are lower middle to middle class in
Cassia Park, Crystal Creek and Mudgeeraba, while Coomera Waters is classified as middle to
upper middle class. There is a significant difference between Mudgeeraba and the other areas
for the average number of people within each household, with means ranging from 2.6 in
Mudgeeraba to 3.8 in Cassia Park. The reason for these differences is seen in family type
statistics. Mudgeeraba possesses the highest percentage of single and coupled households,
(42%), while the other areas, Cassia Park, Crystal Creek and Coomera Waters, possess 14%,
31% and 12% of respectively. Small families are the highest frequency family type in all
areas ranging between 32% for Crystal Creek to 60% for Coomera Waters. Large families
were highest in Cassia Park, making up 29% of the area. Mudgeeraba and Crystal Creek had
the highest percentage of mature couples (14-18%), and families with borders (3-5%). In
general, Mudgeeraba and Crystal Creek possessed similar family type distributions with just
retired couples and large families varying. Coomera Waters contained the highest percentage
of small families (60%), followed by large families at 11%. No response ranged from 10-17%
across the areas.
The trend of more owners than renters was consistent throughout the areas. In terms of
ownership status Mudgeeraba and Cassia Park were similar, renters 22% and 29% and owners
69% and 62% respectively, while Crystal Creek contains more renters (39%) and less owners
(45%), and Coomera Waters had the highest percentage of owners (74%) and a low
proportion of renters (12%). For education status, Mudgeeraba and Cassia Park had similar
frequency distribution with mostly high school educated persons, 44% and 40%, followed by
technical education, 25% and 36%, with tertiary education lowest at 14% and 10%
respectively. Crystal Creek had a reasonably even spread across the education levels, ranging
from 21% high school, 26% technical, 24% tertiary, while 24% of people did not respond.
Coomera Waters possess significantly more households with formal tertiary education, with
43% of the area educated to this level. Similar levels of technically educated persons were
present when comparing Coomera Waters to other areas (26%), while this suburb possessed
the lowest percentage of high school educated people (14%). The descriptive statistics
detailed between the areas demonstrate that some general trends are present, which include a
higher number of owners than renters; the highest family type is small families while the level
of formal education alters with each area. Generally, young couples, single people, families
with borders and share houses only represent a small percentage of the research sample; this
Chapter 4: Situational Context and Descriptive Data Analysis
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indicates that these areas are more densely populated with small and large families, mature
and retired couples. Section 4.2.4 discusses the descriptive statistical differences between the
single and dual reticulated areas.
4.2.4 Comparing single and dual reticulated regions
Objectives of the research included determining the difference in water consumption between
single and dual reticulated regions and, to establish the potable water savings attributed to a
dual reticulated recycled water development. As described in Chapter 3, effort was made to
determine a single reticulated region in the wider Gold Coast City, which comprised of
similar demographic characteristics to those found in PC. ABS demographic statistics were
investigated and Mudgeeraba was found to be the most similar suburb in terms of socio-
demographics. Details of the descriptive socio-demographic statistics of the single reticulated
Mudgeeraba region and the dual reticulated PC regions are presented in Table 4-3.
As detailed in Table 4-3, one of the most significant differences between the single and dual
reticulated regions is the average number of people in households. The single reticulated
region contains 2.6 and the dual reticulated region contains 3.7 people per household. This
data demonstrates that on average, there is at least one more person living in PC households
than those in the Mudgeeraba areas. Because of this difference, end use data is detailed in per
person consumption to eliminate errors. The most common family type in both the single and
dual reticulated regions was small families, which make up 36% and 45% respectively. Some
significant differences are seen between the single and dual reticulated regions between both
retired couples and large families, with 17% versus 4% and 3% versus 19% respectively. This
variation between retired couples and large families explains the higher number of people per
household in the dual reticulated areas. There is also a higher percentage of sole person in the
single reticulated region, 8% versus 2%, while share households make-up 5% in the single
and just 1% in the dual reticulated region. These variations in family type have the potential
to impact on end use water consumption, so again per person values were utilised to aid in all
comparisons.
When comparing the education status of participants some differences are seen between those
educated to high school level and tertiary level between the single and dual reticulated
regions. The single reticulated region participants had 44% of households educated to a high
school level, 25% educated to technical level and 14% educated to a tertiary level. The PC
dual reticulated region had 26% educated to high school level, 30% to technical and 24% to
tertiary level. Generally the dual reticulated region participants were formally educated to
Domestic End Use Investigation: WDM and Dual Reticulation, R.M. Willis (2010)
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higher levels than those in the single reticulated region. The impact of education status on end
use water consumption was considered an interesting point for investigation; Chapter 7 details
how education level influences end use water consumption. These statistics demonstrate the
unique make-up of the dual reticulated PC region when compared with other regions of the
wider Gold Coast. Overall, there is little difference between ownership status between the
regions and while the breakdown of family types is relatively similar, noteworthy differences
are seen between the proportion of retired couples and large families between the regions. The
formal education status of those in the dual reticulated region was generally higher than those
in the single reticulated region. Efforts to minimise the effect of these socio-demographic
variations has been made through detailed explanation of the sample group when end use data
is presented. Understanding the socio-demographics of the research regions assisted in
utilising this data across Gold Coast City. Information outlining the data collection periods,
water restriction regimes, climatic data and total end use water consumption values is
presented in Section 4.3.
4.3 Situational Context of Study
This study involved the collection of end use water consumption data from winter 2008
through to summer 2010 hence the need to explain the context. The three significant data
collection periods occurred in winter 2008, summer 2008 and summer 2009/10. An originally
planned winter 2009 log was not carried out due to the delay in the supply of recycled water
to the PC region but a smaller sub-sample was collected primarily for the educational shower
monitor investigation. Detailed in this section, are water restriction regimes since 2006 and an
overview of monthly climatic trends experienced on the Gold Coast over the past ten years.
Comprehensive climatic data, bulk supplied water consumption and total end use
consumption data for the research period is also presented. All of these conditions were
considered pertinent due to their potential to influence water consumption.
4.3.1 Water restriction regimes over the data collection period
End use water consumption data has been collected over a two year period and throughout
that time water restriction levels have altered. Water restrictions set rules for outdoor watering
and, in times of extreme drought, also aim to restrict internal water consumption. Water
restriction levels on the Gold Coast were originally determined by the local water authority
(i.e. GCW). The Queensland Water Commission (QWC) was established in 2006 and is now
responsible for setting water restriction levels across SEQ. Table 4-4 lists the variations in
Chapter 4: Situational Context and Descriptive Data Analysis
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water restriction levels throughout the research period and provides a description of each
level.
Table 4-4 Gold Coast water restriction overview and timeframe
Level of restriction Description of restriction level Dates active
Level 4
Lawn Watering Ban
Lawn Watering Ban No lawn watering; Hand held hoses only; Odds & evens system applies to residential & non
residential gardens; No watering between 9am and 4pm; No garden watering at all on Mondays; and, Buckets anytime.
1 November 2006
Level 5
Once Per Week Watering
Once per week watering Saturday for odds and Sunday for evens for
residential and non-residential gardens; No Lawn Watering; Hand Held Hoses Only; No watering between 9am and 4pm; and, Buckets anytime.
10 April 2007
Level 6
Total Outdoor Ban
Total outdoor ban Outside hosing or sprinkling is completely banned;
and, Buckets anytime.
23 Nov 2007
Restrictions Lifted Restrictions Lifted No restrictions on indoor or outdoor watering in
place.
9 February 2008
Medium Level Target 200 Hand held hoses only between 4pm & 4.30pm ; Odds & evens system applies to residential & non
residential gardens; Bucket or watering can allowed but not between
8am and 4pm; and, No garden watering at all on Mondays.
27 October 2008
Restrictions Lifted Restrictions Lifted No restrictions on indoor or outdoor watering in
place.
7 January 2009
Permanent Water Conservation Measures
Target 200 (revised from T230) Efficient sprinklers (less than 9 L/minute) and hoses
can be used between 10am & 4pm except on Mondays ;
No garden watering at all on Mondays; Use a bucket or watering can at any time; Pools can be topped up when no alternative supply
source (rainwater tanks) are available; and, High Res programme threshold at 1200 L/day per
household.
1 December 2009
Table 4-4 demonstrates that over the past four years, Gold Coast residents have had a
multitude of different restriction regimes. Restrictions have changed from lawn watering
Domestic End Use Investigation: WDM and Dual Reticulation, R.M. Willis (2010)
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bans, to complete outdoor watering bans, to no restriction level and currently, water
restrictions fall under QWCs Permanent Water Conservation Measure Target of 200L/p/d. As
discussed in Chapter 2, restrictions have been found to significantly influence water
consumption levels hence it is important to be aware of the water restriction level in place
when collecting and analysing consumption data. Over the research period, the most severe
water restriction regime Gold Coast City has experienced is Target 200 L/p/d. Therefore,
Gold Coast residents have been able to irrigate within designated times or with no time
restrictions throughout the entire study. Details on the restriction level experienced over the
data collection period are always outlined when discussing time specific end use data sets due
to the potential impact this may have on the total sample and individual household end use
consumption. Water restriction levels are dictated by the available water supply for the city
which relies heavily upon rainfall hence, an overview of rainfall and other climatic data
assists in understanding the need for water restrictions and the potential demand for irrigation.
Detailed rainfall, temperature and water consumption data experienced through the end use
data collection periods is presented in Section 4.3.2.
4.3.2 Temperature and rainfall patterns on the Gold Coast
Weather patterns on the Gold Coast follow the sub-tropical characteristics of low temperature
and rainfall in winter and high temperature and rainfall in summer. After experiencing a
severe drought period from late 2006 to early 2008, rainfall on the Gold Coast normalised and
has been relatively consistent throughout the research and data collection periods. Figure 4-3
illustrates the monthly recorded rainfall and temperature from 2001 until 2010. Apparent in
Figure 4-3, are the climatic trends of temperature peaks in January and February while the
lowest temperatures are experienced in June and July. Rainfall in the Gold Coast, on average,
is highest between December and March. Rainfall is at its yearly low between July and
October coinciding with the lowest yearly temperatures. Data relevant to the research period,
from winter 2008 to early 2010, demonstrates quite high rainfall throughout 2008/09 and high
rainfall in February 2010 with this being the sixth highest recorded monthly rainfall across the
ten year period. Temperature patterns are reasonably consistent throughout the ten year
period. The 2008/09 and 2009/10 maximum temperatures follow the yearly trend quite
consistently with just August 2009 experiencing slightly higher temperatures than normal.
Details on climatic conditions experienced over the data collection period are always outlined
when discussing time specific end use data sets due to the potential impact this may have on
the total sample and individual household end use consumption. Specific climatic data from
the collection periods along with the bulk supplied water consumption and total recorded end
use water consumption data are discussed in Section 4.3.3.
Chapter 4: Situational Context and Descriptive Data Analysis
- 97 -
Long Term Average Max Temperature and Rainfall vs Actuals
0
5
10
15
20
25
30
35
Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun
Month
Tem
per
atu
re
0
100
200
300
400
500
600
700
800
Rai
nfa
ll (m
m)
2001/02 Rainfall 2002/03 Rainfall 2003/04 Rainfall2004/05 Rainfall 2005/06 Rainfall 2006/07 Rainfall2007/08 Rainfall 2008/09 Rainfall 2009/10 RainfallLTA Average Max Temp 2001/02 Max Temp 2002/03 Max Temp2003/04 Max Temp 2004/05 Max Temp 2005/06 Max Temp2006/07 Max Temp 2007/08 Max Temp 2008/09 Max Temp2009/10 Max Temp LTA Mean Rainfall
Figure 4-3 Yearly temperature and rainfall patterns for the Gold Coast, Queensland
Domestic End Use Investigation: WDM and Dual Reticulation, R.M. Willis (2010)
- 98 -
4.3.3 Climate, bulk recorded supply and end use data throughout the study period
End use data was collected at various intervals over the duration of the study. As noted, the major data
collection periods occurred in winter 2008, summer 2008 and summer 2009/10. Additional end use data
was collected throughout 2009 to determine the extent to which the introduction of an educational
shower monitor device reduced shower end use water consumption. Temperature and rainfall can
significantly influence water consumption, particularly outdoor irrigation hence a detailed description of
the average temperatures and rainfall over the duration of the study is presented in Table 4-5. Gold Coast
City monthly bulk supplied water consumption data is detailed in per capita consumption. This figure is
calculated by GCWs demand forecaster, using the daily water volumes supplied to the city with
adjustments made for assumed losses, the forecasted population, the percentage of population served and
the percentage of consumption predicted to be used by residents. Additionally potable and recycled, bulk
supplied water consumption data for the PC dual reticulation region is also presented separately and as a
combined total per capita consumption. This data was extracted from GCW quarterly bulk billing records
hence, the same PC data is presented for each month within that quarter. Table 4-5 also demonstrates the
end use data collection periods, highlighted in grey, with total per capita end use consumption data
presented. All data detailed in Table 4-5 is for single detached residential households only.
Climatic trends presented in Table 4-5 mirror those seen in Figure 4-3, with high rainfall and
temperatures throughout summer and low temperatures and rainfall in winter. Table 4-5 shows that the
first data collection period in winter 2008, fell within an un-seasonally high rainfall period. This is
reflected in both the city wide bulk supplied and end use data being the lowest recorded over the study
period. The PC bulk supplied data is higher than the recorded end use total but this would be due to the
amalgamation of the quarterly data not reflecting the true consumption for the month of July.
Considering the average PC combined consumption between the month of June and July (i.e.
(136+199)/2 = 169 L/p/d) the end use value seems on par again, demonstrating the difficulty in
comparing end use data to three month billing records. Both the end use data and the bulk supplied data
from winter 2008 demonstrate that residents in the PC area were consuming more than those in single
reticulated regions across Gold Coast City.
Significantly high rainfall in November 2008 and relatively high rainfall in December 2008 resulted in
low bulk supply and end use water consumption data. The end use water consumption data collected in
this period was significantly lower than that recorded through the city wide monthly bulk supply and the
PC combined supply. The reason for this may have been the end use data collection two week period
occurred when the highest rainfall days were recorded for the month, hence minimal irrigation use and
much lower end use water consumption volumes than the bulk supplied data.
Chapter 4: Situational Context and Descriptive Data Analysis
- 99 -
Table 4-5 Climatic, bulk supply and end use water consumption data from Gold Coast City
Year Month Mean
Max.
Temp.
Mean
Min.
Temp.
Total
Rainfall
Mean
number of
days of
rain >1mm
GC City Wide
Pot. Bulk
Supplied Res.
Water (L/p/d)
PC Dual
Retic. Pot.
Bulk Supplied
Res. Water
(L/p/d)
PC Dual
Retic. Rec.
Bulk Supplied
Res. Water
(L/p/d)
PC Dual Retic.
Combined Bulk
Supplied Res.
Water (L/p/d)
End Use Water
Consumption
Single Retic.
(L/p/d)
End Use Water
Consumption
Dual (PC)
Retic. (L/p/d)
End Use Water
Consumption
Combined
(L/p/d)
2008 June 22.99 13.0 95.8 7 164.81 109 27 136
July 21.05 11.35 129.8 10 161.90 161 38 199 153.4 (n=38) 158.5 (n=113) 157.2 (n=151)
August 22.36 9.87 0.8 0 171.30 161 38 199
September 24.42 15.51 74.8 8 169.63 161 38 199
October 26.15 16.22 107.6 8 177.64 146 36 182
November 27.32 19.11 440.6 14 173.67 146 36 182
December 29.74 20.4 123.8 11 176.85 146 36 182 158.3 (n=29) 143.5 (n=98) 150.9 (n=127)
2009 January 29.65 22.08 93.2 10 196.31 148 39 187
February 29.80 21.74 167.4 13 176.56 148 39 187
March 28.58 20.78 91.4 13 181.02 148 39 187
April 26.76 18.14 385.6 11 189.81 128 35 163
May 23.83 14.99 183.4 9 186.99 128 35 163 172.5 (n=7) 163.4 (n=27) 168.0 (n=34)
June 21.40 12.25 139.8 11 180.58 128 35 163
July 21.37 11.36 7.2 2 188.93 155 37 192
August 24.58 13.56 0.8 2 204.08 155 37 192
September 25.29 14.3 13 2 214.00 155 37 192
October 26.60 16.45 20.8 5 222.28 146 43 189
November 28.66 19.95 52 7 213.25 146 43 189
December 28.85 18.4 107.8 8 224.36 146 43 189 205.3 (n=7) 282.4 (n=24) 243.9 (n=31)
2010 January 30.37 22 73.8 7 221.54 162 39 201
February 29.26 22.11 299.8 15 194.67 162 39 201
March 28.08 21.51 185.2 14 191.93 162 39 201 146.9 (n=27) 155.4 (n=73) 153.1 (n=100)
April 27.23 19.19 56.4 7 192.10
- 100 -
The end use data collected in this period showed that PC residents were consuming less than
those in single reticulated regions (Table 4-5). While this is not reflected in the bulk supplied
data evidence exists in the following month.
A small end use sample was collected in May 2009 for the purpose of the educational shower
monitor investigation. While the original research scope included a winter 2009 end use data
log, this did not occur due to the delay in recycled water supply. The May 2009 end use data
was collected over a relatively high rainfall period for this month (Figure 4-3). The end use data
collected is reasonably aligned with the data presented from the city wide bulk supply and very
closely aligned to the PC bulk billed supply data. The end use data corresponds with the bulk
supply data with single reticulated residents consuming more than those in the PC area (Table
4-5).
Data collection over summer 2009/10 occurred twice to capture high and low rainfall periods. In
December 2009, a sample of 31 homes end use was captured within the highest bulk supplied
consumption period over the period of the study. The reason for the small sample size (n=31)
was due to significant failures in equipment. Data was collected in the first two weeks in
December just after the supply of recycled water to the PC region and before rain occurred in
the final week of the month. Table 4-5 demonstrates that the end use data from December
captured the highest consumption experienced on the Gold Coast in two years. Interestingly,
end use data in Table 4-5 reflects that residents in the PC region consumed significantly more
total water than those in the single reticulated region although this is opposite to that captured
by the bulk supply data. The reason for the significantly higher total end use consumption value
was because much of the data was collected in the highest socioeconomic region of Coomera
Waters. This area has much larger lot sizes and hence they were consuming significantly more
water externally for irrigation. The bulk recorded data for the PC region also contains numerous
multi and dual occupancy households with small external spaces, hence the significantly lower
value.
The second collection phase in March 2010 fell within a high rainfall period with 185.2mm of
rainfall recorded with 14 rainfall days over 1mm. Bulk supplied consumption for the wider Gold
Coast City was 191.93 L/p/d, which is higher than 2009 March consumption but lower than
summer consumption. Combined water consumption (potable + recycled) in the PC region
based on three month billing data was 201 L/p/d with 162 L/p/d being potable use and 39 L/p/d
being recycled water use. Combined bulk recorded water consumption in the PC region was
higher than that recorded for Gold Coast City. The bulk billing figures demonstrate that 80.6%
of total consumption is potable water, while 19.4% is recycled water. The end use data collected
Chapter 4: Situational Context and Descriptive Data Analysis
- 101 -
during this month was significantly lower than that recorded through bulk billing. The single
reticulated end use monitored consumption was 146.9 L/p/d, which is 23% lower than that
recorded through bulk consumption. The dual reticulated area consumption demonstrated even
higher discrepancies between end use and bulk billing data with 155.4 L/p/d end use
consumption recorded and 201 L/p/d of bulk use recorded. The reason for these discrepancies
may be due to the collection period falling within the higher rainfall time interval, the sample
size being too small to reflect the average city wide consumption or due to the differences in
actual end use data versus bulk supplied and bulk billed data.
Overall, the end use data collected across the two year period follows the trends presented in the
bulk supplied and bulk billed data. There is evidently a difference between the end use water
consumption data and bulk supplied and billed data. Many factors could be contributed to these
differences. Some of which could be:
The end use data collection period of two weeks falling within a high or low rainfall
period of the month or a high or low temperature period when bulk data is looking at
monthly averages. The variation in rainfall and temperature was found to significantly
influence end use water consumption totals, namely through external usage. The March
2010 end use logging period was a good example of how data collection in the wetter
part of the month resulted in a difference of 21% when compared against monthly bulk
supplied averages.
The bulk supply and bulk billing data contains numerous estimations and assumptions
on the number of people that water is being supplied to or the per person consumption.
These population averages are based on Gold Coast’s desired standards of service
calculations and population estimates within Infrastructure Demand Models. The end
use per person consumption is based on household surveys and hence posses
significantly higher accuracy than citywide population data. For example, the average
occupancy of households within the GCWSEU study was 3.4 (see Table 4-2) while the
average occupancy in Gold Coast’s Desired Standards of Service is 2.73 (GHD, 2009).
If single reticulated data is used for comparison at a household level then the bulk
supplied consumption is 524 L/HH/d (191.93 L/p/d x 2.73) and the end use water
consumption is 499 L/HH/d (146.9 L/p/d x 3.4) then the variation in these consumption
values is just 5% not 23%. Hence, the level of accuracy obtained through the end use
study gives a more representative indication of actual per person consumption within a
household.
The research sample may not reflect the Gold Coast city wide consumption as the
recruited sample group may not represent the general consumption behaviours across
the city. Unfortunately it is often the case that more willing residents participate in
research projects which is often due to perceived belief of displaying the correct
Domestic End Use Investigation: WDM and Dual Reticulation, R.M. Willis (2010)
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behaviour which, in this case is being water efficient. To ensure a representative sample
was obtained, the total end use consumption of the recruited sample group were
analysed to evaluate representativeness. Chapter 5 presents details of this investigation
which demonstrated that a wide range of water consumers were present within the
sample group.
The research sample population changed significantly throughout the research period.
Due to the long sampling timeframe of the research, it is apparent that the sample group
recruited at the beginning of the research would vary by the end. To ensure the most
accurate population data, the local billing system was checked and additional phone
calls/on-site discussions occurred to clarify occupancy rates within sampled households.
In depth breakdowns of end use water consumption data in each of the data collection periods
noted above are presented in Section 4.4.
4.4 End Use Water Consumption Data
Collection of end use water consumption data occurred in winter 2008, summer 2008 and
summer 2009/10. This section presents the detailed end use water consumption data from each
of these collection periods.
4.4.1 Winter 2008
The winter 2008 end use water consumption data collection period occurred in July. Gold Coast
City was not on any level of water restrictions but the city had recently experienced a severe
drought period which involved complete outdoor watering bans and an array of successful
demand management initiatives to reduce residential consumption. At this point in time,
residents still seemed to be consuming at low levels between 160 and 165 L/p/d (Table 4-5). In
July 2008, Gold Coast city experienced un-seasonally high rainfall of 129.8mm; with ten days
in this month incurring rain above 1mm. Bulk supplied residential consumption was 161.9
L/p/d, just slightly higher than June consumption but 10 L/p/d less than in August 2008. There
was no recycled water supplied to the PC region at this time. Figure 4-4 details the total end use
water consumption break down for the research sample (n=151) for winter 2008.
Chapter 4: Situational Context and Descriptive Data Analysis
- 103 -
Figure 4-4 Average daily per capita consumption for total sample in winter 2008 (n=151)
The break down of end use water consumption for the total Gold Coast sample (n=151) is
shown in Figure 4-4. The average consumption for the sampled homes was 157.2 L/p/d. Shower
end use consumption was the highest at 32% or 49.7 L/p/d followed by clothes washer at 19%
or 30.0 L/p/d. Tap use, toilet flushing and irrigation account for end use percentages of 17%,
13% and 12%, respectively. Bath use, dishwashing and leaks make up a small component of
water end use with percentages ranging from 1% to 4%. The break down of the single and dual
reticulated regions is detailed in Figure 4-5 and Figure 4-6. The figures present both potable and
recycled water consumption as these water sources are still supplied and recorded through two
separate water meters for all data logging periods including winter 2008.
As previously noted, recycled water was not yet supplied to the PC region in winter 2008.
Figure 4-5 and Figure 4-6 illustrate the single and dual reticulated end use water consumption
respectively. The total consumption for the single reticulated region was 153.4 L/p/d while the
dual reticulated region was slightly higher at 158.5 L/p/d. The consumption volumes are
relatively similar between the two areas for shower, clothes washer, tap, toilet and dishwasher.
Difference is seen between the volumetric use for bathtub perhaps due to more small and large
families in the PC region. Combined irrigation is also somewhat higher in the PC dual
reticulated region (Figure 4-6). Leakage is higher in the single reticulated region. Overall, the
winter 2008 data log demonstrated that the end use water consumption of the single and dual
reticulated regions was quite similar and hence comparison between the two regions was
reasonable.
Clothes Washer
30.0L/p/d19.1%
Shower49.7 L/p/d
31.6%
Tap27.0L/p/d
17.2%
Dishwasher2.2L/p/d
1.4%
Bathtub6.5 L/p/d
4.2%
Toilet (total)21.1 L/p/d
13.4%
Irrigation (Total)
18.6L/p/d11.8%
Leak (Total)2.1L/p/d
1.3%
Average Daily Per Capita Consumption (L/p/day): Single+Dual (n=151)
Total = 157.2 L/p/d
Domestic End Use Investigation: WDM and Dual Reticulation, R.M. Willis (2010)
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Figure 4-5 Average daily per capita consumption for single reticulated region in winter 2008 (n=38)
Figure 4-6 Average daily per capita consumption for dual reticulated region in winter 2008 (n=113)
Table 4-6 details the end use water consumption break down for the individual research areas. It
should be noted that there are two single reticulated homes in the PC region. These were the
existing homes in place before the dual reticulated PCWF Master Plan was implemented. These
homes are included in the single reticulated figures but remain in their equivalent socio-
demographic area for the tables, as seen in Table 4-6.
Clothes Washer
26.8 L/p/d17.5%
Shower55.4 L/p/d
36.2%
Tap30.1 L/p/d
19.6%
Dishwasher1.8 L/p/d
1.2%
Bathtub3.2 L/p/d
2.1%
Toilet (Pot)19.3 L/p/d
12.6%
Irrigation (Pot)13.9 L/p/d
9.1%
Leak (Pot)2.7 L/p/d
1.8%
Average Daily Per Capita Consumption (L/p/day): Single Reticulation (n=38)
Clothes Washer
31.1 L/p/d19.6%
Shower47.7 L/p/d
30.1%
Tap26.0 L/p/d
16.4%
Dishwasher2.4 L/p/d
1.5%
Bathtub7.6 L/p/d
4.8%
Toilet (Rec)21.7 L/p/d
13.7%
Irrigation (Pot)10.0 L/p/d
6.3%
Irrigation (Rec)10.2 L/p/d
6.4%
Leak (Pot)1.2 L/p/d
0.7%
Leak (Rec)0.7 L/p/d
0.4%
Average Daily Per Capita Consumption (L/p/day): Dual Reticulation (n=113)
Total = 158.5 L/p/d
Total = 153.4 L/p/d
Chapter 4: Situational Context and Descriptive Data Analysis
- 105 -
Table 4-6 Winter 2008 end use data for research regions
End use category Mudgeeraba (n=36)
Cassia Park (n=42)
Crystal Creek (n=38)
Coomera Waters (n=34)
L/p/d Percent L/p/d Percent L/p/d Percent L/p/d Percent Clothes washer 27.3 17.6% 32.2 21.2% 31.4 20.1% 28.5 17.2% Shower 56.3 36.2% 50.2 32.9% 44.2 28.3% 48.2 29.1% Tap 30.4 19.5% 24 15.8% 27.8 17.8% 26.5 16% Dishwasher 1.9 1.2% 1.8 1.2% 2.7 1.7% 2.6 1.5% Bathtub 3.4 2.2% 8.7 5.7% 6 3.8% 7.7 4.6% Toilet (Pot) 19.2 12.3% 0.8 0.5% 0.3 0.2% 0 0% Toilet (Rec) NA NA 20.6 13.5% 21.4 13.7% 22.1 13.3% Irrigation (Pot) 14.5 9.3% 5.9 3.9% 10.3 6.6% 14.2 8.5% Irrigation (Rec) NA NA 6.2 4% 10.9 6.9% 13.7 8.3% Leak (Pot) 2.6 1.7% 1.1 0.7% 1 0.6% 1.7 1.1% Leak (Rec) NA NA 0.8 0.5% 0.5 0.3% 0.6 0.4% Total (Pot) 155.6 100% 124.7 82.0% 123.7 79.1% 129.4 78.0% Total (Rec) NA NA 27.6 18.0% 32.8 20.9% 36.4 22.0% Total (Pot + Rec)
155.6 100% 152.3 100% 156.5 100% 165.8 100%
Note: Pot = potable supply line, Rec = recycled supply line
In Mudgeeraba, recycled consumption for toilet, irrigation and leak are not applicable as this is
the single reticulated region without recycled water supply. Clothes washer use is higher in
Cassia Park and Crystal Creek; the lower and middle dual reticulation regions (Table 4-6).
Showering is the highest end use across all the regions with the highest consumption occurring
in Mudgeeraba and the lowest in Crystal Creek. Dishwasher use is highest in the middle and
high socioeconomic areas Crystal Creek and Coomera Waters due to higher ownership in these
areas. Toilet use is generally consistent across the regions. Combined irrigation use is the
highest in Coomera Waters followed by Crystal Creek, Mudgeeraba and Cassia Park. This trend
is consistent with greater use in higher socioeconomic areas.
4.4.2 Summer 2008
The summer 2008 end use water consumption data collection occurred primarily through
December. At this point in time, Gold Coast city was on QWC medium level restrictions of
Target 200 L/p/d. Before this data collection commenced, November 2008 experienced extreme
monthly rainfall totalling 440.6mm with, 14 rainfall days above 1mm (Table 4-5). This was the
third highest rainfall month on the Gold Coast between 2001 and 2010. December 2008 also
saw reasonably high rainfall of 123.8mm and 11 rainfall days with over 1mm of rain.
Understandably, bulk supplied residential consumption was low in December being just 176.9
L/p/d, this increased to 196.3 L/p/d the next month of January 2009. Recycled water was not
supplied to the PC region for this data collection period. Figure 4-7 details the total end use
water consumption breakdown for the research sample (n=127) for summer 2008.
Domestic End Use Investigation: WDM and Dual Reticulation, R.M. Willis (2010)
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Figure 4-7 Average daily per capita consumption for total sample in summer 2008/09 (n=127)
The break down of end use water consumption for the total Gold Coast sample (n=127) is
presented in Figure 4-7. The average consumption for the sampled homes was 150.9 L/p/d.
Figure 4-7 shows that shower end use consumption remained the highest at 32% or 48.4 L/p/d
followed by clothes washer at 19% or 29.0 L/p/d. These consumption values are almost the
same as those recorded in the winter 2008 data log. Tap use, toilet flushing and irrigation
account for end use percentages of 18%, 14% and 9%, respectively. Bath use, dishwashing and
leaks make up a small component of water end use with percentages ranging from 1% to 5%.
Figure 4-8 and Figure 4-9 detail the single and dual reticulated end use water consumption
respectively. The total consumption for the single reticulated region was 158.3 L/p/d while the
dual reticulated region was 9% lower at 143.5 L/p/d. Again, the consumption volumes are
relatively similar between the two areas for shower, clothes washer, tap, toilet and dishwasher.
In this data logging period, total irrigation consumption is almost equal with the single
reticulated region consuming 12.7 L/p/d or 8% and the dual reticulated region using 13.1 L/p/d
(potable + recycled) or 9%. The outstanding differentiator between the two regions is the high
leakage in the single reticulated region. This accounts for 13.0 L/p/d or 8% of total end use,
while the dual reticulated region only experienced a combined leakage of 2.1 L/p/d or 1.5%.
This large leakage volume was due to one single reticulated house having an ongoing leak
across the entire data collection period. This high leakage volume is the reason for the higher
water consumption in the single reticulated region in summer 2008. Apart from leakage, most
end uses have very similar volumetric consumption values in both the single and dual
Clothes Washer
29.0 L/p/d19.2%
Shower48.4 L/p/d
32.1%
Tap27.4 L/p/d
18.2%
Dishwasher2.1 L/p/d
1.4%
Bathtub2.0 L/p/d
1.3%
Toilet (Total)21.5 L/p/d
14.3%
Irrigation (Total)
12.9 L/p/d8.6%
Leak (Total)7.5 L/p/d
5.0%
Average Daily Per Capita Consumption (L/p/day):Single + Dual (n= 127)
Total = 150.9 L/p/d
Chapter 4: Situational Context and Descriptive Data Analysis
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reticulated regions. Table 4-7 details the individual areas end use water consumption in summer
2008.
Figure 4-8 Average daily per capita consumption for single reticulated region in summer 2008/09 (n=29)
Figure 4-9 Average daily per capita consumption for dual reticulated region in summer 2008/09 (n=98)
Table 4-7 Summer 2008/09 end use data for research regions
Clothes Washer
28.3 L/p/d17.9%
Shower51.1 L/p/d
32.3%
Tap28.6 L/p/d
18.1%
Dishwasher2.1 L/p/d
1.3%
Bathtub1.4 L/p/d
0.9%
Toilet (Pot)21.2 L/p/d
13.4%
Irrigation (Pot)12.7 L/p/d
8.0%
Leak (Pot)13.0 L/p/d
8.2%
Average Daily Per Captia Consumption (L/p/day):Single Reticulation (n= 29)
Total = 158.3 L/p/d
Clothes Washer
29.7 L/p/d20.7%
Shower45.6 L/p/d
31.8%
Tap26.3 L/p/d
18.3%
Dishwasher2.2 L/p/d
1.5%
Bathtub2.6 L/p/d
1.8%
Toilet (Rec)21.9 L/p/d
15.3%
Irrigation (Pot)6.9 L/p/d
4.8%
Irrigation (Rec)6.2 L/p/d
4.3%
Leak (Pot)1.4 L/p/d
1.0%
Leak (Rec)0.7 L/p/d
0.5%
Average Daily Per Capita Concumption (L/p/day):Dual Reticulation (n= 98)
Total = 143.5 L/p/d
Domestic End Use Investigation: WDM and Dual Reticulation, R.M. Willis (2010)
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End use category Mudgeeraba (n=27)
Cassia Park (n=36)
Crystal Creek (n=33)
Coomera Waters (n=31)
L/p/d Percent L/p/d Percent L/p/d Percent L/p/d Percent Clothes washer 29 20% 28.5 19.8% 28.8 19.7% 31.3 20.8% Shower 51.3 35% 42.5 29.5% 47.6 32.5% 47.5 31.6% Tap 28.2 19% 23.2 16.1% 29.5 20.2% 26.9 17.9% Dishwasher 2.1 1% 1.4 1% 2.5 1.7% 2.7 1.8% Bathtub 1.5 1% 2.9 2% 2.9 1.9% 1.9 1.3% Toilet (Pot) 20.2 14% 1.4 0.9% 0.6 0.4% 0 0% Toilet (Rec) NA NA 19.7 13.7% 21.2 14.5% 23.9 15.9% Irrigation (Pot) 12.3 8% 7.6 5.3% 6 4.1% 7.9 5.3% Irrigation (Rec) NA NA 5.8 4% 5.7 3.9% 6.8 4.5% Leak (Pot) 3.5 2% 10.4 7.2% 1 0.7% 0.3 0.2% Leak (Rec) NA NA 0.6 0.4% 0.5 0.4% 0.9 0.6% Total (Pot) 148.1 100% 117.9 81.9% 118.9 81.2% 118.5 79.0% Total (Rec) NA NA 26.1 18.1% 27.4 18.8% 31.6 21.0% Total (Pot + Rec)
148.1 100% 144 100% 146.3 100% 150.1 100%
Table 4-7 demonstrates that significant leakage occurred in a single reticulated home in Cassia
Park. Leakage across the other areas was low with Mudgeeraba experiencing the highest
leakage of the other three areas. Across the areas clothes washing volumes are consistent with
Coomera Waters being just slightly higher than the others. Shower use is highest in Mudgeeraba
followed by Coomera Waters, Crystal Creek and Cassia Park. Toilet use is very similar across
the areas, while irrigation is again highest in the high socioeconomic region followed by
Mudgeeraba. Total consumption is relatively similar across the areas with the highest
socioeconomic region consuming the most (i.e. Coomera Waters at 150.1 L/p/d) followed by
Mudgeeraba, Crystal Creek and Cassia Park.
4.4.3 December 2009
End use water consumption data was collected in a high use period and lower use period in
December 2009 and March 2010 to capture the differences in recycled water consumption. The
data collection period in December 2009 contained a small sample due to significant equipment
failures from water intrusion in the water meters and data loggers. As at the 1st of December
2009, the Gold Coast City was on the QWC Permanent water conservation target level of 200
L/p/d. For almost a year, the city was not under any water restriction level and the progressive
rise in monthly water consumption can be seen across 2009 (Table 4-5). When comparing 2008
and 2009 Gold Coast City monthly water consumption, 2009 consumption is always higher than
the equivalent 2008 month. Higher temperatures and low rainfall resulted in city wide
consumption going above 200L/p/d in August 2009, with bulk supplied water consumption
peaking in December 2009 at 224.36 L/p/d. Recycled water consumption was at its highest
recorded from January to March 2010. December 2009 experienced high rainfall volumes of
107.8mm but this occurred in the last week of the month after high temperatures and no rainfall
in the first three weeks of December, hence just eight rainfall days over 1mm noted. As at 1st of
December 2009, recycled water was supplied to the PC region. The commissioning of recycled
Chapter 4: Situational Context and Descriptive Data Analysis
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water was launched with an extensive awareness campaign promoting the supply and use of
recycled water in the PC region. It is believed that these high temperatures, no rainfall and
promotional campaign for recycled water supply encouraging use is why end use water
consumption in the dual reticulated areas was so high. Further detail of the break down of
internal versus external irrigation (Table 4-8) in the dual reticulated recycled water areas
demonstrates significant irrigation usage. Figure 4-10 details the total end use water
consumption break down for the research sample in this period (n=33), Figure 4-11 and Figure
4-12 detail the end use consumption in the single and dual reticulated regions in December
2009. Table 4-8 demonstrates the research areas individual end use water consumption details.
Figure 4-10 Average daily per capita consumption total sample December 2009 (n=33)
The break down of end use water consumption for the total Gold Coast sample (n=33) is
demonstrated in Figure 4-10. The average consumption for the sampled homes was 243.9 L/p/d
an increase in consumption of 66% since the summer 2008/09 end use data log. Figure 4-10
details that irrigation was the highest end use in the home at 39% or 95.7 L/p/d a significant
increase in irrigation when compared with other end use data logging periods. The reason for
this high irrigation use was the hot and dry climatic conditions combined with the supply and
encouragement of recycled water use in the PC region. Volumetric shower consumption
remained similar to that seen in summer 08/09 at 46.2 L/p/d. Clothes washing end use increased
when compared to summer 08/09, to 38.7 L/p/d of total use. Again, tap and toilet volumetric
consumption remained similar to those recorded in other end use logging periods at 28.7 or 24.2
L/p/d respectively. Bathtub, dishwasher and leakage in December 2009 were low, ranging
between 1-2% of total use. The significant increase in total water consumption in December
2009 was the result of high irrigation use. While some other end uses increased slightly such as
Clothes Washer
38.7 L/p/d15.9%
Shower46.2 L/p/d
18.9%
Tap28.7 L/p/d
11.8%
Dishwasher2.2 L/p/d
0.9%
Bathtub3.3 L/p/d
1.3%
Toilet (Total)24.2 L/p/d
9.9%
Irrigation (Total)
95.7 L/p/d39.2%
Leak (Total)4.9 L/p/d
2.0%
Average Daily Per Capita Concumption (L/p/day):Single + Dual (n= 33)
Total = 243.9 L/p/d
Domestic End Use Investigation: WDM and Dual Reticulation, R.M. Willis (2010)
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clothes washer, the large consumption increase is primarily a result of irrigation. Capturing this
high total consumption and irrigation consumption is pertinent for the consideration of peak use
periods in modelling and planning water infrastructure. The break down of the single and dual
reticulated regions end use consumption is demonstrated in Figure 4-11 and Figure 4-12.
Figure 4-11 Average daily per capita consumption single reticulated region in December 2009 (n=7)
Figure 4-11 and Figure 4-12 detail the single and dual reticulated end use water consumption
respectively. Only seven homes were captured in the single reticulated region with data
demonstrating that shower use remained highest, followed by clothes washing and irrigation.
Data from the dual reticulated region showed that irrigation on the recycled water line was by
far the highest end use at 91.8 L/p/d or 33% of total use. This data demonstrates successful
uptake and preference of recycled water use for irrigation in the dual reticulated areas. Irrigation
on the potable line was the next highest in the dual reticulated region at 54.6 L/p/d or 19%.
Clothes washer and shower use was lower in volumetric consumption than that in the single
reticulated region although this difference may be due to the low sample sizes in each group.
Tap, toilet and dishwasher consumption were reasonably similar, while leakage and bathtub end
use was higher in the dual reticulated region as has been the trend throughout. Table 4-8 details
the December 2009 end use breakdown for each individual area.
Clothes Washer
47.4 L/p/d23.1%
Shower51.9 L/p/d
25.3%
Tap32.0 L/p/d
15.6%
Dishwasher2.2 L/p/d
1.1%
Bathtub2.6 L/p/d
1.3%
Toilet (Pot)22.2 L/p/d
10.8%
Irrigation (Pot)45.0 L/p/d
21.9%
Leak (Pot)2.0 L/p/d
1.0%
Average Daily Per Captia Consumption (L/p/day):Single Reticulation (n= 7)
Total = 205.3 L/p/d
Chapter 4: Situational Context and Descriptive Data Analysis
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Figure 4-12 Average daily per capita consumption dual reticulated region in December 2009 (n=26)
Table 4-8 Summer December 2009 end use data for research regions
End use categories
Mudgeeraba (n=5)
Cassia Park (n=5)
Crystal Creek (n=7)
Coomera Waters (n=12)
L/p/d Percent L/p/d Percent L/p/d Percent L/p/d Percent Clothes washer 43.8 23.8% 23.7 19.4% 32.3 15.3% 32.5 8% Shower 45.2 24.5% 37 30.1% 33.7 16% 49.9 12.2% Tap 25.3 13.7% 19.1 15.6% 25.8 12.2% 30.5 7.4% Dishwasher 2.2 1.2% 1.5 1.3% 3.1 1.5% 1.9 0.5% Bathtub 2.6 1.4% 3.3 2.7% 4.8 2.3% 3.4 0.8% Toilet (Pot) 18.3 9.9% 5.5 4.5% 0 0% 0 0% Toilet (Rec) NA NA 17.5 14.3% 25.1 11.9% 29.3 7.2% Irrigation (Pot) 45 24.4% 5.9 4.9% 14.7 7% 104.9 25.7% Irrigation (Rec) NA NA 8 6.5% 70.6 33.5% 140.1 34.3% Leak (Pot) 1.8 1% 0.6 0.5% 0.3 0.2% 0.8 0.2% Leak (Rec) NA NA 0.2 0.2% 0.5 0.2% 15.2 3.7% Total (Pot) 184.2 100% 96.6 79% 114.7 54.4% 223.9 54.8% Total (Rec) NA NA 25.7 21% 96.2 45.6% 184.6 45.2% Total (Pot + Rec)
184.2 100% 122.3 100% 210.9 100% 408.5 100%
The December 2009 end use data logging period contain a very small sample size, Table 4-8
details the relevant number of homes monitored in each area. Such a small, non-significant
number of homes mean that end use data cannot be relied upon hence; general comments will be
made but are not considered applicable for the individual areas. Clothes washer use is highest in
Mudgeeraba, followed by Coomera Waters, Crystal Creek and Cassia Park. Shower use is
highest in Coomera Waters with Mudgeeraba and Cassia Park the next highest. Tap use is not as
consistent as normally seen across the various areas demonstrating the need for a larger sample
size to make appropriate conclusions. Of interest is the irrigation use across the suburbs.
Coomera Waters, the highest socioeconomic region with the largest property sizes, consumed
Clothes Washer
30.1 L/p/d10.7%
Shower40.5 L/p/d
14.3%
Tap25.4 L/p/d
9.0%
Dishwasher2.2 L/p/d
0.8%
Bathtub3.9 L/p/d
1.4%
Toilet (Rec)26.2 L/p/d
9.3%
Irrigation (Pot)54.6 L/p/d
19.3%
Irrigation (Rec)91.8 L/p/d
32.5%
Leak (Pot)0.5 L/p/d
0.2%
Leak (Rec)7.2 L/p/d
2.6%
Average Daily Per Capita Concumption (L/p/day):Dual Reticulation (n= 26)
Total = 282.4 L/p/d
Domestic End Use Investigation: WDM and Dual Reticulation, R.M. Willis (2010)
- 112 -
by far the highest irrigation volume on both the potable and recycled water lines. In fact,
recycled and potable irrigation in Coomera Waters accounted for 60% of the total end use for
that area. Irrigation on the recycled water line is higher across all of the dual reticulated areas
ranging from 8 L/p/d in Cassia Park to 140.1 L/p/d in Coomera Waters. While the data in Table
4-8 is not significant, it does present some interesting trends. Data from the March 2010 end use
logging period is now presented.
4.4.4 March 2010
As stated, two end use data collection periods were undertaken when recycled water was
supplied to the PC dual reticulated areas. The March 2010 log contained a higher sample size
than the December 2009 log as equipment was repaired, a total of 100 homes were captured.
The QWC Permanent Water Conservation target of 200 L/p/d was still applied in March 2010.
The month of March experienced average temperatures and high rainfall of 185.2mm with 14
days experiencing more than 1mm of rainfall. The rainfall was twice that in March 2009 and
higher than rainfall volumes historically experienced within the month of March. Effort was
made to record in lower rainfall periods albeit rainfall was quite consistent throughout the
month. The bulk supplied single reticulation water consumption volume for the city was 191.93
L/p/d, just slightly lower than consumption in April 2010. Recycled water consumption in the
PC region, as per bulk supplied data, was 201 L/p/d in total with 162 L/p/d consumed through
the potable supply and 39 L/p/d consumed on the recycled water supply. Figure 4-13 details the
total end use water consumption break down for the research sample in March 2010 (n=100),
Figure 4-14 and Figure 4-15 detail the end use consumption in the single and dual reticulated
regions in December 2009. Table 4-9 demonstrates the research areas individual end use water
consumption details.
The break down of end use water consumption for the total Gold Coast sample in March 2010
(n=100) is demonstrated in Figure 4-13. The average consumption for the sampled homes was
153.1 L/p/d which is significantly lower than the bulk supplied single reticulation consumption
of 191.93 L/p/d. Figure 4-13 details that shower was the highest end use in the home at 29.9%
or 45.8 L/p/d which is consistent with shower end use consumption recorded in other data
logging periods. Irrigation significantly decreased from that recorded in December 2009 due to
the high rainfall volume and days. Total irrigation accounted for just 8.7% of end use or 13.3
L/p/d. Tap use and clothes washing accounted for the next highest end uses after shower, being
30.8 L/p/d and 30.2 L/p/d respectively. Clothes washing were somewhat lower than that
recorded in December 2009 but consistent with volumetric end use recorded in other data
logging periods indicating that clothes washing increases in hot, dry conditions.
Chapter 4: Situational Context and Descriptive Data Analysis
- 113 -
Figure 4-13 Average daily per capita consumption total sample March 2010 (n=100)
Tap use was consistent with earlier end use recording periods. Again toilet volumetric
consumption remained similar to those recorded in other end use logging periods at 27.4 L/p/d.
Bathtub, dishwasher and leakage in March 2010 were low ranging between 1.1-1.3% of total
use. The break down of the single and dual reticulated regions end use consumption is
demonstrated in Figure 4-14 and Figure 4-15.
Figure 4-14 Average daily per capita consumption single reticulated region in March 2010 (n=27)
Clothes Washer
30.2 L/p/d19.7%
Shower45.8 L/p/d
29.9%
Tap30.8 L/p/d
20.1%
Dishwasher2.0 L/p/d
1.3%
Bathtub1.9 L/p/d
1.2%
Toilet (Total)27.4 L/p/d
17.9%
Irrigation (Total)
13.3 L/p/d8.7%
Leak (Total)1.7 L/p/d
1.1%
Average Daily Per Capita Consumption (L/p/day): Single+Dual (n=100)
Total = 153.1 L/p/d
Clothes Washer
30.3 L/p/d20.7%
Shower47.1 L/p/d
32.1%Tap
31.0 L/p/d21.1%
Dishwasher1.1 L/p/d
0.8%
Bathtub1.4 L/p/d
0.9%
Toilet (Pot)20.9 L/p/d
14.2%
Irrigation (Pot)14.4 L/p/d
9.8%
Leak (Pot)0.7 L/p/d
0.4%
Average Daily Per Capita Consumption (L/p/day): Single Reticulation (n=27)
Total = 146.9 L/p/d
Domestic End Use Investigation: WDM and Dual Reticulation, R.M. Willis (2010)
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Figure 4-14 demonstrates that shower use remained the highest at 47.1 L/p/d, followed by
clothes washer and tap use at 30.3 and 31.0 L/p/d respectively for the 27 single reticulated
homes. These end use volumetric consumption volumes were similar to those found in earlier
data logging periods. Irrigation was slightly higher in the single reticulated region, accounting
for 14.4 L/p/d or 9.8% of total use, when compared with the dual reticulated region of 12.9
L/p/d or 8.3% of total use.
Figure 4-15 Average daily per capita consumption dual reticulated region in March 2010 (n=73)
In dual reticulated region showering was the highest end use consumption at 45.3 L/p/d
followed equally by tap use and clothes washer at 30.7 and 30.1 L/p/d. Table 4-9 details the
March 2010 end use breakdown for each individual area.
The March 2010 end use data logging period saw the logging of an equal number of properties
in each research region. The consumption rates across the different regions are relatively similar
with the lowest total consumption at Mudgeeraba and the highest at Coomera Waters. The
highest recycled water consumption was at Cassia Park due to toilet use. The highest recycled
water irrigation was at Coomera Waters being 8.5 L/p/d or 5.4%. Shower was the highest end
use event accounting for between 47.8, 49.2, 44.2 and 41.4 L/p/d in Mudgeeraba, Coomera
Waters, Crystal Creek and Cassia Park respectively. Clothes washing use remained highest in
Mudgeeraba, followed by Crystal Creek, Cassia Park and Coomera Waters. Tap and toilet usage
followed as next highest end uses. Total irrigation was significantly lower in March with the
highest usage being 16.4 L/p/d or 10.5% at Coomera Waters, followed by 15.4 L/p/d or 10.2%
at Mudgeeraba. Total irrigation at Cassia Park and Crystal Creek only accounted for 7% and
6.9% respectively.
Clothes Washer
30.1 L/p/d19.4%
Shower45.3 L/p/d
29.2%
Tap30.7 L/p/d
19.8%
Dishwasher2.3 L/p/d
1.5%
Bathtub2.1 L/p/d
1.3%
Toilet (Rec)29.8 L/p/d
19.2%
Irrigation (Pot)6.3 L/p/d
4.1%
Irrigation (Rec)6.6 L/p/d
4.2%
Leak (Pot)1.0 L/p/d
0.7%
Leak (Rec)1.1 L/p/d
0.7%
Average Daily Per Capita Consumption (L/p/day): Dual Reticulation (n=73)
Total = 155.4 L/p/d
Chapter 4: Situational Context and Descriptive Data Analysis
- 115 -
Table 4-9 March 2010 End use data for research regions
End use categories
Mudgeeraba (n=25)
Cassia Park (n=25)
Crystal Creek (n=25)
Coomera Waters (n=25)
L/p/d Percent L/p/d Percent L/p/d Percent L/p/d Percent Clothes washer 32.3 21.5% 28.6 18.8% 32.5 21.1% 27.4 17.5% Shower 47.8 31.8% 41.4 27.3% 44.2 28.8% 49.7 31.8% Tap 31.1 20.7% 32.7 21.5% 28.9 18.8% 30.5 19.6% Dishwasher 1.0 0.6% 2.1 1.4% 2.8 1.8% 1.9 1.2% Bathtub 1.5 1.0% 0.5 0.3% 3.4 2.2% 2.2 1.4% Toilet (Pot) 20.7 13.8% 1.1 0.8% 0.7 0.5% 0 0% Toilet (Rec) NA NA 32.4 21.3% 28.6 18.6% 26.1 16.7% Irrigation (Pot) 15.4 10.2% 5.2 3.4% 5.5 3.5% 7.9 5.1% Irrigation (Rec) NA NA 5.5 3.6% 5.2 3.4% 8.5 5.4% Leak (Pot) 0.7 0.4% 1.1 0.7% 1.3 0.9% 0.6 0.4% Leak (Rec) NA NA 1.4 0.9% 0.6 0.4% 1.3 0.8% Total (Pot) 150.4 100% 112.8 74.2% 119.3 77.6% 120.2 77.1% Total (Rec) NA NA 39.3 25.8% 34.4 22.4% 35.9 22.9% Total (Pot + Rec)
150.4 100% 152.1 100% 153.7 100% 156.1 100%
4.4.5 Summary of all end use water consumption data
Sections 4.4.1 to 4.4.4 detailed the end use water consumption data for each individual data
collection period. Numerous similarities are evident when comparing end use water
consumption data from the various data collection periods, particularly for indoor consumption.
Presented in this section, is the overall indoor and outdoor consumption for the entire study
period. Figure 4-16 illustrates the average indoor end use water consumption from the entirety
of the research duration. All data from single and dual reticulated households has been included
to determine this average indoor consumption.
Figure 4-16 demonstrates that shower usage is the highest end use water consuming activity,
accounting for 47.5 L/p/d or 34.6% of average indoor water usage. Clothes washing follows as
the second highest end use at 21.9% or 30.1 L/p/d. Tap and toilet use account for 27.7 and 23.0
L/p/d respectively. Leakage is the highest of the smaller indoor end uses at 3.1 L/p/d or 2.2%.
Bathtub and dishwasher account for 3.9 and 2.1 L/p/d respectively. While irrigation
consumption altered over the data collection periods due to climatic and other influencing
factors, an average of indoor and outdoor consumption for the entire study duration was
considered pertinent (Figure 4-17).
Domestic End Use Investigation: WDM and Dual Reticulation, R.M. Willis (2010)
- 116 -
Clothes Washer
30.1 L/p/d18.6%
Shower47.5 L/p/d
29.4%
Tap27.7 L/p/d
17.2%
Dishwasher2.1 L/p/d
1.3%
Bathtub3.9 L/p/d
2.4%
Toilet (total)23.0 L/p/d
14.2%
Irrigation (Total)
24.1 L/p/d14.9%
Leak (Total)3.1 L/p/d
1.9%
Average Daily Per Capita Consumption Total Study (L/p/day):
Single + Dual (n=412)
Figure 4-16 Gold Coast indoor water consumption for entire study period (n=412)
Figure 4-17 Gold Coast total (indoor and outdoor) water consumption for entire study period (n=411)
As seen in Figure 4-17, the inclusion of irrigation alters the percentage distribution across the
end uses while volumetric use remains the same. Shower still remains the highest end use at
47.5 L/p/d or 29.4% of total end use. Clothes washer is the next highest end use at 30.1 L/p/d or
18.6% of the total end use. Irrigation accounts for 24.1 L/p/d or 14.9% of total end use. Tap and
toilet use still account for 27.7 and 23.0 L/p/d or 17.2% and 14.2% respectively. Leak, bathtub
and dishwasher remain low with the same volumetric use and percentages of 1.9%, 2.4% and
Total = 161.5 L/p/d
Clothes Washer
30.1 L/p/d21.9%
Shower47.5 L/p/d
34.6%
Tap27.7 L/p/d
20.2%
Dishwasher2.1 L/p/d
1.6%
Bathtub3.9 L/p/d
2.8%
Toilet (total)23.0 L/p/d
16.7%
Leak (Total)3.1 L/p/d
2.2%
Average Daily Per Capita Consumption Total Study Indoor (L/p/day):
Single + Dual (n=412)
Total = 137.4 L/p/d
Chapter 4: Situational Context and Descriptive Data Analysis
- 117 -
1.3% respectively. As seen in earlier sections, irrigation is very dependent on climatic
conditions while indoor consumption remains relatively consistent throughout.
4.5 Chapter Summary
This chapter examined the situational context and described the research sample through
descriptive statistical analysis. The chapter also presented detailed end use water consumption
data from each of the logging periods and a summary of total end use from the entirety of the
study’s duration. Spatial images demonstrated the location of the research areas in relation to
Gold Coast city and within each study area. The sample sizes from the individual research
activities showed relatively high uptake. Research sample characteristics allowed for labelling
and classification of research areas based on their socioeconomic status. The descriptive
statistics of research areas and participants described household densities, ownership status and
family types. All relevant research context variables were presented, which included water
restrictions levels and climatic conditions including rainfall and temperature. Detailed data on
supply and consumption from bulk meter read data were also divulged. Overall, this chapter
presented data and conditions considered pertinent to the remaining peer-reviewed paper
chapters. Chapter 5 presents the first peer-reviewed paper chapter which introduces the Gold
Coast Watersaver End Use study and details initial end use water consumption results.
4.6 References
NSW DET (2009) What is socio-economic status? State of New South Wales, Department of Education and Training and Charles Sturt University. Online article. Available: http://www.hsc.csu.edu.au/ab_studies/rights/global/social_justice_global/sjwelcome.status.front.htm.
Rooy, E. & Engelbrecht, E. (2003) Experience With Residential Water Recycling At Rouse Hill. Sydney Water, Sydney.
SPSS (2010) Data Collection Family: PASW. Online article. Available: http://www.spss.com/software/data-collection/ SPSS: An IBM Company, Chicago.
Vyas, S. & Kumaranayake, L. (2006) Constructing socio-economic status indicies: how to use principal components analysis. Health Policy and Planning, Vol 26:6, pp. 459-468.
Chapter 5
Gold Coast Domestic End Use Study This chapter is a reformatted version of a peer-reviewed article completed by the author which,
has been published in the Water Journal of Australian Water Association Vol 36:6 (2009) pp.
84-90.
5.1 Abstract
This paper presents the preliminary findings of the Gold Coast Watersaver End Use Project
which was conducted in winter 2008, for 151 homes on the Gold Coast, Australia. Specifically,
the paper includes a break down of water end use consumption data, compares this with results
of previous national studies, and explores the degree of influence of household socioeconomic
regions on end use. Two highly variable water end use distributions, namely shower and
irrigation, were examined in detail, clustered and are discussed herein. The paper concludes
with a brief description of the greater ongoing research program.
5.2 Introduction
Following a long-standing drought, many regions in south east Queensland are experiencing
strict water restrictions and have seen the introduction of a portfolio of other demand
management and supply initiatives to ensure the provision of a secure water supply. Residential
water consumption is often dependent on the fixtures or device stock within a house, household
makeup, region location and psychosocial influences. A study of end use water consumption
aids water planners and users to identify where and when water is used in a household hence
assisting to drive proactive reductions in consumption (Loh and Coghlan, 2003).
In Australia, two major end use studies have been undertaken in Perth (Loh and Coghlan, 2003)
and the Yarra Valley, Melbourne (Roberts, 2005). Internationally, several studies have been
conducted in the United States of America (Mayer and DeOreo, 1999; Mayer et al., 2004) and
recently in New Zealand (Heinrich, 2007). However, the end use models determined by these
studies differ depending on a range of factors including the year conducted, climate, restriction
regime, yard size, water using devices or fixtures and the household makeup (Roberts, 2005).
In addition, it has been acknowledged that community attitudes and behaviours can also
influence the effectiveness of water savings resulting from water demand management
Chapter 5: Gold Coast Domestic End Use Study
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strategies (Corral-Verdugo et al., 2002). In the USA, Mayer and DeOreo (1999) explored
certain relationships between water consumption and demographic variables at the end use
level. Their research suggested that demographic variables such as family size and age
distribution, wealth or income, ownership status, and household attitudes towards using and
conserving water, influence household water consumption (Mayer and DeOreo, 1999; Taverner
Research, 2005; Turner et al., 2005; Kenney et al., 2008). However, in Australia, minimal
research has been undertaken on investigating end use water consumption with relation to
demographic variables within monitored homes.
5.3 The Gold Coast Watersaver End Use Study
There are no end use water consumption models currently available for South East Queensland.
This region has a sub-tropical climate and has recently experienced severe drought conditions
which forced both State and Local Governments to develop numerous strategies to reduce water
usage. Griffith University and Gold Coast Water have collaborated under an Australian
Research Council (ARC) grant to conduct an investigation of end use water consumption in the
Gold Coast area. Other primary objectives of the research are to examine the effectiveness of
dual reticulation and education as potable water saving mechanisms. The research will result in
datasets of end use water consumption, demographic information and attitudinal data, diurnal
patterns for potable and recycled supplies, and data on the effective potable water savings
attributed to dual reticulation and developed education initiatives. As stated by Kenney et al.
(2008, pp. 196), the collection and integration of such datasets especially ‘household level
consumption data with demographic data about the people and house’, rarely occurs. Figure 5-1
presents the schedule and key deliverables for the Gold Coast Watersaver End Use research
project. This paper only reports findings from the pre-intervention phase of the study, which
includes the winter 2008 end use data recorded before the supply of recycled water to Pimpama
Coomera.
5.4 Research Method
The selected dual reticulated region was segregated into three socioeconomic categories to assist
in obtaining a reliable overview of the population. A single reticulated region was selected for
comparison. The date of estate development of the single reticulated region was similar to that
of the dual reticulated region (i.e. 5-10 years) to ensure higher efficiency fixtures were present
in both regions and leakage within households was comparable.
Domestic End Use Investigation: WDM and Dual Reticulation, R.M. Willis (2010)
- 120 -
Figure 5-1 Gold Coast Watersaver End Use study project schedule
Data was collected in winter 2008 during which time there were no water restrictions in place
due to the Gold Coast’s primary water source, the Hinze Dam, being greater than 95% capacity.
In total, 151 houses were monitored which included 38 single reticulated and 113 dual
reticulated households. No recycled water (Class A+ is Queensland’s highest quality for
recycled water, not intended for drinking purposes) was being supplied as the Pimpama recycled
water treatment plant had not yet been commissioned. Moreover, no awareness campaign had
been launched to encourage the uptake of recycled water in the dual reticulated region. Thus,
the two datasets were treated as one sample for the purpose of this present study (Willis et al.,
2009a). Once recycled water is commissioned (3rd quarter of 2009), it is expected that a clear
distinction will be present between single and dual reticulated households, predominately due to
higher irrigation use within the latter sample. The Future Work section details consideration of
this change.
Participants were recruited through a multi-staged process of letters and door knocking.
Selection of participants was based on criteria which included: household ownership status
(renting/owning); household makeup; willingness to be involved in research for two years;
acceptance of multiple water consumption monitoring periods and surveys with potential
interventions and; involvement in a water fixture/appliance stock audit. It should also be noted
Chapter 5: Gold Coast Domestic End Use Study
- 121 -
that historical household volumetric readings were analysed for the consenting sample to ensure
that they were representative of the region and the broader Gold Coast.
Upon recruitment completion, existing standard residential water meters were replaced with
high resolution water meters and data loggers to enable obtainment of end use water
consumption data. The modified Actaris CTS-5 water meters pulse at a rate of 72 counts per
litre of water consumed, this equates to an individual recording every 0.014 L of water use.
Aegis DataCell D-CZ21020 data loggers were connected to water meters to record water
consumption. Data loggers were set to record information every ten seconds over a two week
period which resulted in fourteen days of end use data for each household. Figure 5-2
demonstrates the equipment configuration and section 5.4.1 outlines the water end use trace
analysis process.
Basic surveys focusing primarily on demographic information were distributed to sample
households. Surveys were conducted to solicit household demographic information, including:
(1) household address and region; (2) resident numbers, gender, age, employment, weekly
income, education status and relationship of people within the house; and (3) household
ownership status. This paper focuses on analysing the relationship between water consumption
patterns within the following socioeconomic regions of the Gold Coast: (a) Cassia Park: low
socioeconomic group; (b) Mudgeeraba: low to middle socioeconomic group; (c) Crystal Creek:
middle socioeconomic group; and (d) Coomera Waters: middle to high socioeconomic group.
The water end use information for the listed socioeconomic groups was clustered to enable
comparative analysis to determine whether relationships between demographic groupings and
water consumption exist.
5.4.1 End use analysis process in brief
The reed switch on traditional volumetric water meters is modified to collect a high resolution
record of water use (i.e. from the traditional 2 to 72 pulses per litre or 0.014 litres per pulse)
which can then be disaggregated into individual water use events using a flow trace analysis
software tool (e.g. Trace Wizard©). The high resolution water measurement information from
the meter is then captured by attached high data capacity loggers (i.e. 2 million readings)
recording information at a pre-set time intervals (e.g. 10 seconds). Time scaled flow recording
information is then collected in-situ through infrared cables or wirelessly through a mobile
phone network. Once a representative sample of data is collected the flow trace analysis
software tool is applied to disaggregate flow traces into a list of component events assigned to a
specific end use appliance or fixture (e.g. shower, toilet, washing machine, etc.). Stock and
behaviour surveys are typically utilised to help the analyst develop templates which encapsulate
the appliance properties of end use events and ensure accurate end use categorisation. Once
Domestic End Use Investigation: WDM and Dual Reticulation, R.M. Willis (2010)
- 122 -
trace analysis is completed and confirmed, a database registry of all end use events occurring
during the sampled period is established and subsequently utilised for water planning and
management research as demonstrated herein. Readers should refer to the Residential End Use
Measurement Guidebook for further information (Giurco et al., 2008).
Figure 5-2 Data loggers and collection technique
5.5 Results and Discussion
5.5.1 Water end use on the Gold Coast
The break down of water end use consumption, on a per person basis, for the sampled
households in the Gold Coast (n=151) is presented in Figure 5-3. The average consumption for
sampled Gold Coast households is 157.2 L/p/d (n=151). The highest end use is showering with
each person consuming almost 50 litres of water a day equating to 33% of total use. Clothes
washing follows equating for 19% of total consumption or 30 L/p/d. Tap use, toilet flushing and
irrigation account for end use percentages of 17%, 13% and 12%, respectively. Bath use,
dishwashing and leaks make up a small component of water end use with percentages ranging
from 1% to 4%.
5.5.2 End use comparison with previous studies
Table 5-1 shows a comparative summary of Australian and Pacific end use studies including the
Gold Coast results.
Chapter 5: Gold Coast Domestic End Use Study
- 123 -
Figure 5-3 Average daily per person consumption (L/p/d): combined sample (n=151)
Table 5-1 Comparison between national and pacific water end use consumption studies
Previous studies Present study End use category
Perth (2003) Melbourne (2005) Auckland (2007) Gold Coast (2008)
L/p/d Percent L/p/d Percent L/p/d Percent L/p/d Percent Clothes washer 42.0 13% 40.4 19% 39.9 24% 30.0 19% Shower 51.0 15% 49.1 22% 44.9 27% 49.7 33% Tap 24.0 7% 27.0 12% 22.7 14% 27.0 17% Dishwasher NA NA 2.7 1% 2.1 1% 2.2 1% Bathtub NA NA 3.2 2% 5.5 3% 6.5 4% Toilet (total) 33.0 10% 30.4 13% 31.3 19% 21.1 13% Irrigation (total) 180† 54% 57.4† 25% 13.9 8% 18.6 12% Leak (total) 5.0 1% 15.9 6% 7.0 4% 2.1 1% Other NA NA 0.0 0% 0.8 0% 0.0 0% Total Consumption
335.0 100% 226.2 100% 168.1 100% 157.2 100% †Note: Irrigation volume per person calculated from provided volumes per household and end use break downs.
Table 5-1 demonstrates that total consumption and certain end use percentages vary between
regions. Gold Coast consumption is the lowest recorded consumption of all studies being 157.2
L/p/d. The general trend is a reduction in total water consumption over time (i.e. 2003 to 2008).
This reduction is probably due to the mounting intensity of water restrictions and increasingly
frequent exposure to information on sustainable water consumption. This paradigm shift of
societal water values has influenced water consumption, though elasticity will tighten in the
future.
Irrigation end use percentages and volume vary significantly between each study. Perth
recorded the highest irrigation volumes of up to 54% or 180 L/p/d. Auckland recorded the
lowest irrigation consumption due to winter data collection, followed by the Gold Coast. Gold
Clothes Washer
30.0L/p/d19.1%
Shower49.7 L/p/d
31.6%
Tap27.0L/p/d
17.2%
Dishwasher2.2L/p/d
1.4%
Bathtub6.5 L/p/d
4.2%
Toilet (total)21.1 L/p/d
13.4%
Irrigation (Total)
18.6L/p/d11.8%
Leak (Total)2.1L/p/d
1.3%
Average Daily Per Capita Consumption (L/p/day): Single+Dual (n=151)
Total = 157.2 L/p/d
Domestic End Use Investigation: WDM and Dual Reticulation, R.M. Willis (2010)
- 124 -
Coast irrigation is low as data was recorded during a winter with unseasonably high rainfall;
recording and analysis of summer data will assist in verifying this deduction. Evidently,
irrigation volumes play a key role in altering end use percentages.
Generally, leakage makes up a very small component of water end use. Melbourne recorded the
highest leakage factor of 6% (15.9 L/p/d), whilst leakage at the Gold Coast only made up 1%
(1.4 L/p/d). This should be due to the fact that monitored Gold Coast households were all
constructed in the last five years, whereas Melbourne’s housing stock is much older.
5.5.3 End use comparison: percentage or volume?
On first inspection of Table 5-1, with the exception of Perth (due to high irrigation volumes),
the percentage break down for end uses appear relatively similar for clothes washing, tap use,
dishwashers and toilets whilst variation of end use percentages are evident for showers,
irrigation and leakage. Recorded shower consumption was the highest in the Gold Coast (2008)
at 33% and the lowest in Perth (2003) at 15%. However, on closer inspection, shower
volumetric consumption was relatively equal being 51.0 L/p/d in Perth and 49.7 L/p/d in the
Gold Coast. This raises contention of simply using percentage figures for comparison. The
variability between volumetric and percentage consumption observed for showers is repeated
for clothes washing which, makes up 13 to 19% of end use in Perth, Melbourne and the Gold
Coast. On closer examination, the actual volume of consumption for clothes washing is quite
varied. A similar trend exists for toilet flushing with end use percentages being relatively
comparable ranging between 10 to 14% of end use but when comparing volumetric rates, the
Perth study recorded 33 L/p/d and the Gold Coast study found toilet consumption at 21.1 L/p/d.
Again this reinforces the concept that volumetric consumption should be utilised as a basis of
comparison rather than end use percentages.
The key contributor to the reduction in volumes evident in the more recent Gold Coast study
would be the installation of modern efficient toilets and washing machines, largely driven by
recently ceased State and local government rebate schemes for efficient fixtures and appliances.
As a final note, tap and dishwasher percentages and volumetric consumption were relatively
comparable across the studies.
5.5.4 End use comparison for individual households
Figure 5-4 demonstrates the end use water consumption break down for each of the measured
151 households. It also illustrates the proportion of sampled households within each of the
Queensland Water Commission (QWC) restriction regime categories, upon which the Gold
Chapter 5: Gold Coast Domestic End Use Study
- 125 -
Coast Local Government Area must conform (i.e. Target 140: Extreme Level; Target 170: High
Level; Target 200: Medium Level; and Target 230: Permanent Water Conservation Measures).
0.00
50.00
100.00
150.00
200.00
250.00
300.00
350.00
400.00
450.00
Household ID
L/p
c/d
Leak (Total)
Irrigation (Total)
Toilet (Total)
Bathtub
Dishwasher
Tap
Shower
Clothes Washer
Queensland Water Commission Target Ranges (140, 170, 200 and 230 L/pc/d)<230 201 - 230 171 - 200 141 - 170 <140
21 homes(14%)
13 homes(9%)
20 homes(13%)
27 homes(18%)
70 homes(46%)
Figure 5-4 Household daily per capita consumption: activity break down
While there were no restrictions during data collection on the Gold Coast, Figure 5-4
demonstrates that almost half of the research population (46%) consumed less than 140.0 L/p/d.
Water consumption is highly varied between individual households with the highest per capita
use equating to 390.0 L/p/d whilst the lowest use was as little as 38.4 L/p/d. The substantial
difference between the highest and lowest per capita consumption volumes demonstrates that a
range of water users are present in the research sample. Considerable variation between
individual end use is also demonstrated in Figure 5-4.
The variation in clothes washer use between individual households seen in Figure 5-4 is largely
due to the diversity of clothes washing machines within homes, as established through stock
surveys. The water volume consumed by a single load of clothes washing can vary from 42
L/wash to 176 L/wash (Commonwealth of Australia, 2008d) this obviously has a significant
impact on resulting consumption. Water use for bathtubs appears to be minimal and scattered
across the sample. Generally, baths were taken in houses with young children whereas older
children and adults typically showered. Toilet and tap consumption varies and does not seem to
be dependent on other end uses. Dishwasher use varies between individual households, as it is
highly dependent on residential behaviours. No visible reduction in tap use is present in
households that have dishwashers although this is a trend to investigate further. Figure 5-4
illustrates that the more discretionary shower and irrigation end uses can be core contributors to
the total consumption level of households. The water use patterns of these two activities are
further explored in Figure 5-5 and Figure 5-6, respectively.
Domestic End Use Investigation: WDM and Dual Reticulation, R.M. Willis (2010)
- 126 -
0.00
50.00
100.00
150.00
200.00
250.00
Household ID
L/p
c/d
Daily Per Capita Distribution: Shower
10%
40%
19% 18%
13%
0%
5%
10%
15%
20%25%
30%
35%
40%
45%
<20 21-40 41-60 61-80 >80
L/pc/d
Rel
ativ
e F
req
uen
cy (
%)
13% of homes use 30% of total shower water
13% of homes use 30% of total shower water
Figure 5-5 Household daily per capita consumption: shower only
Figure 5-5 shows that 13% of households consumed 30% of the total water utilised for
showering. This highlighted sub-sample (13%) constitutes a non-linear shower use pattern as
opposed to the remaining research population (87%) which shows a relatively linear rate of
change in consumption. The distribution of shower use, as illustrated in the Figure 5-5 insert,
demonstrates that half of the population used less than 40 L/p/d of water for showering which is
equivalent to a 5 minute shower at 8L/min. For the remaining categories, 37% of households
use between 41 to 80 L/p/d with the high user group (13%) consuming more than 80 L/p/d in
the shower.
0.00
50.00
100.00
150.00
200.00
250.00
Household ID
L/p
c/d
Daily Per Capita Distribution: Irrigation
76%
11%6% 7%
0%
10%
20%
30%
40%
50%
60%
70%
80%
<20 21-40 41-60 >61
L/pc/d
Rel
ativ
e F
req
uen
cy (
%)
24% of homes use 80% of total irrigation water
Figure 5-6 Household daily per capita consumption: irrigation only
Figure 5-6 demonstrates that 24% of the sampled households contribute to an exponential rate
of change in water consumption for irrigation. This represents a group of high users consuming
80% of the total irrigation water of the entire sample, with the maximum consumption level as
high as 225.9 L/p/d. In addition, the per capita distribution presented in the inset of Figure 5-6
shows that the majority of households (76%) used less than 20 L/p/d of water for irrigation.
Maximum = 173.4L/p/d
Maximum = 225.9L/p/d
Chapter 5: Gold Coast Domestic End Use Study
- 127 -
End use comparison: households from different socioeconomic regions
For the purpose of this study, four socioeconomic regions were selected and compared, namely:
(a) low (Cassia Park: n=42); (b) low to middle (Mudgeeraba: n=36); (c) middle (Crystal Creek:
n=38); and (d) middle to high (Coomera Waters: n=35). Figure 5-7 displays the end use values
for these four socioeconomic regions.
0.0
20.0
40.0
60.0
80.0
100.0
120.0
140.0
160.0
180.0
L/p
c/d
Leak (Total)
Irrigation (Total)
Toilet (Total)
Bathtub
Dishwasher
Tap
Shower
Clothes Washer
Leak (Total) 1.9 2.6 1.5 2.4
Irrigation (Total) 12.1 14.5 21.1 27.8
Toilet (Total) 21.4 19.2 21.6 22.1
Bathtub 8.7 3.4 6.0 7.7
Dishwasher 1.8 1.9 2.7 2.6
Tap 24.0 30.4 27.8 26.5
Shower 50.2 56.3 44.2 48.2
Clothes Washer 32.2 27.3 31.4 28.5
Cassia Park Mudgeeraba Crystal Creek Coomera Waters
155.6152.2156.2
165.8
Figure 5-7 Average daily per capita water consumption: socioeconomic regions
Previous studies have suggested that high volume water consumers are wealthier, older and live
in new and larger homes (Kim et al., 2007; Kenney et al., 2008). Residents in Coomera Waters
(higher socioeconomic region) were the largest consumers per capita, using 165.8 L/p/d with
Crystal Creek residents (middle socioeconomic region) following consuming 156.2 L/p/d.
Water consumption of Mudgeeraba residents (low to middle socioeconomic region) was 155.6
L/p/d while Cassia Park residents (lower socioeconomic region) consumed the least being 152.2
L/p/d. While these differences are not significant, they support previous research.
The volume of water used for clothes washing is lowest in Coomera Waters and Mudgeeraba
being 28.5 L/p/d and 27.3 L/p/d respectively. Cassia Park recorded the highest clothes washing
consumption at 32.2 L/p/d whilst Crystal Creek residents consumed 31.4 L/p/d for clothes
Domestic End Use Investigation: WDM and Dual Reticulation, R.M. Willis (2010)
- 128 -
washing. It is suggested that households with higher income levels are more likely to purchase
higher efficiency washing machines hence the differences in consumption.
Shower consumption seems to oppose this trend, although not significantly. The lower
socioeconomic regions (Cassia Park and Mudgeeraba) showed higher consumption. This trend
may be attributed to lower efficiency of shower roses or variations in shower behaviour. The
trend of lower shower consumption volumes with more efficient devices has previously been
established (Mayer et al., 2004).
Irrigation usage is notably lower in Cassia Park with only 12.1 L/p/d being consumed compared
with 14.5 L/p/d in Mudgeeraba, 21.1 L/p/d in Crystal Creek, and 27.8 L/p/d in Coomera Waters.
This could be attributed to the fact that lower socioeconomic groups tend to have smaller lot and
garden sizes and minimal ownership of pools. Finally, there is no significant difference in bath
and toilet consumption among the four suburbs, suggesting no relationship between this
particular water use activity and the change in socioeconomic regions.
5.6 Conclusion
This paper presented initial findings from the Gold Coast Watersaver End Use Study based on
data collected in winter 2008. It was established that end use water consumption varies
significantly between individual households and noticeably between socioeconomic regions.
The data demonstrates the lowest recorded end use water consumption per person in comparison
to previous national and pacific end use studies. Future data collection periods over summer aim
to capture increased consumption attributed to seasonal use. Overall, the data provided
confirmation that high socioeconomic regions consume more water per capita than lower
socioeconomic regions. Details of ongoing and planned research activities are briefly discussed
below.
5.7 Future Work
Figure 5-1 detailed the numerous components of the Gold Coast Watersaver End Use Study to
be undertaken over the coming year. Recycled water (Class A+ is Queensland’s highest quality
for recycled water, not intended for drinking purposes) will be supplied to the Pimpama
Coomera region in 2009. Summer end use data collection will be completed to ascertain the end
use uptake of recycled water. This data will assist in verifying end use assumptions made in the
planning phases of the Pimpama Coomera development. Moreover, a world first dual
reticulation end use model including diurnal patterns in both the potable and recycled water
supply pipelines will be completed. Variation in diurnal patterns between single and dual (i.e.
Chapter 5: Gold Coast Domestic End Use Study
- 129 -
recycled water also supplied) reticulated homes will also be explored. This data will provide a
comprehensive understanding of water consumption at a given time providing greater
understanding on the individual end uses affecting peak loads.
The impact of a range of education or awareness demand management interventions will also be
tested. One such intervention program includes the evaluation of an alarming visual display
monitor device on shower event durations, flow rates and volumes, thus providing quantitative
evidence on the influence of this initiative on shower water conservation behaviours. Other
programs will involve the provision of detailed end use information to users and the effect this
has on consumption.
The above stated components of the end use study will culminate in the development of a
comprehensive domestic end use model for the Gold Coast as well as evidence that supports, or
otherwise, the effect of water demand management measures, principally dual reticulation and
awareness/education programs, for conserving precious potable water supplies.
For further information on the Gold Coast Watersaver End Use Study please visit either:
http://www.griffith.edu.au/engineering-information-technology/centre-infrastructure-
engineering-management/gold-coast-watersaver-end-use-project or
http://www.goldcoastwater.com.au/t_gcw.asp?PID=7591
5.8 References
Commonwealth of Australia (2008) Water Efficiency Labelling and Standards Scheme: Product Search (Clothes Washing Machine). Available online: http://www.environment.gov.au/wels_public/searchPublic.do, accessed 14/12/08.
Corral-Verdugo, Bechtel, R. & Fraijo-Sing, B. (2003) Environmental beliefs and water conservation: An empirical study. Environmental Psychology, 23, pp 247–257.
Giurco, D., Carrard, N., McFallan, S., Nalbantoglu, M., Inman, M., Thornton, N. & White, S. (2008a) Residential end-use measurement guidebook: a guide to study design, sampling and technology. Prepared by the Institute for Sustainable Futures, UTS and CSIRO for the Smart Water Fund, Victoria.
Heinrich, M. (2007) Water End Use and Efficiency Project (WEEP) - Final Report. BRANZ Study Report 159. Judgeford, New Zealand, Branz.
Kenney, D., Goemans, C., Klein, R., Lowrey, J. & Reidy, K. (2008) Residential water demand management: lessons from Aurora, Colorado. Journal of the American Water Resources Association, Vol. 44:1, pp. 192-207.
Kim, S. H., Choi, S. H., Koo, J. K., Choi, S. I. & Hyun, I. H. (2007) Trend analysis of domestic water consumption depending upon social, cultural, economic parameters. Water Science and Technology: Water Supply, Vol 7, No 5-6, pp. 61-68.
Domestic End Use Investigation: WDM and Dual Reticulation, R.M. Willis (2010)
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Loh, M. & Coghlan, P. (2003) Domestic Water Use Study. Perth, Water Corporation.
Mayer, P., DeOreo, W., Towler, E., Martien, L. & Lewis, D. (2004) Tampa Water Department residential water conservation study: The impacts of high efficiency plumbing fixture retrofits in single-family homes. Aquacraft, Inc Water Engineering and Management, Tampa.
Mayer, P. W. & DeOreo, W. B. (1999) Residential End Uses of Water. Aquacraft, Inc. Water Engineering and Management, Boulder, CO.
Roberts, P. (2005) Yarra Valley Water 2004 Residential End Use Measurement Study. Melbourne, Yarra Valley Water.
Taverner Research (2005) Survey of Household Water Attitudes. Surry Hills, NSW, Taverner Research.
Turner, A., White, S., Beatty, K. & Gregory, A. (2005) Results of the largest residential demand management program in Australia. Institute for Sustainable Futures, University of Technology. Sydney Water Corporation, Sydney, NSW
Willis, R., Stewart, R., Chen, L. & Rutherford, L. (2009) Water end use consumption analysis into Gold Coast dual reticulated households: Pilot. Australia’s National Water Conference and Exhibition: OzWater'09, Melbourne Convention & Exhibition Centre, Melbourne, March 16-18, 2009. Melbourne.
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Chapter 6
End use water consumption in households: impact of socio-demographic factors and
efficient devices
This chapter is a reformatted version of a peer-reviewed article completed by the author, under
review (October 2010) for publication in the Journal of Cleaner Production.
6.1 Abstract
Assessing water savings in households using efficient devices and how savings vary between
different sectors of the community, requires high resolution end use water consumption data
(i.e. disaggregating water use for showers, toilets, clothes washers and garden irrigation etc.).
This paper reports selected findings from the Gold Coast Watersaver End Use Study (Australia),
which focussed on the relationship between a range of socio-demographic and household stock
efficiency variables and water end use consumption levels. A mixed methods approach was
executed using qualitative and quantitative data. The study provided evidence as to the potential
savings derived from efficient appliances as well as socio-demographic clusters having higher
water consumption across end uses. The payback period for some water efficient devices was
also explored. The study has implications for urban water demand management planning and
forecasting.
6.2 Introduction
6.2.1 Improving urban water security
The strong emphasis on ensuring a secure water supply for the population of Australia has been
brought to light by the increasing frequency, severity and duration of drought events throughout
the nation. Drought, coupled with growing populations has lead to numerous instances of many
water supply reservoirs in South-East Queensland (SEQ) dropping below 20% over the last
decade. This has forced State and Local government to implement alternative water supply
schemes, along with a range of demand management interventions, in order to improve urban
water security. Innovative water re-use and decentralised supply solutions are becoming
increasingly viable technologies to meet city water needs but there are often many financial,
behavioural and regulatory barriers to their diffusion in practice (Partzsch, 2009; Giurco et al.,
2010; Krozer et al., 2010). Planning studies employing holistic Integrated Water Resource
Domestic End Use Investigation: WDM and Dual Reticulation, R.M. Willis (2010)
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Management (IWRM) models (Dvarioniene and Stasiskiene, 2007) have been applied and
demonstrated that high efficiency water fixtures and appliances are a least cost planning strategy
for water conservation and a good starting point for policy makers before higher cost water
supply or demand solutions are commissioned (Stewart et al., 2010).
6.2.2 Domestic water consumption and conservation
In the case at the Gold Coast, Australia residential water consumption accounts for
approximately 66% of the City’s total supply (07/08). In Brisbane total residential consumption
is 57%. Residential water consumption has previously been determined to be influenced by
seasonal changes and water demand management (WDM) strategies such as water metering,
water restriction levels, water efficient devices and education (Nieswaidomy, 1992; Mayer et
al., 2004; Inman and Jeffrey, 2006). Although prior research in these areas has occurred it is
well established that there is a requirement for specific country and location based research due
to different community attitudes and behaviours which can influence the effectiveness of WDM
strategies (Corral-Verdugo et al., 2002; Turner et al., 2005). To grasp the effectiveness of
WDM strategies high quality data is required. The development of smart metering technologies
and end use analysis techniques allowed for the acquisition of such data.
6.2.3 Advent of smart water metering
In the case at the Gold Coast, Australia – a city of 510,000 people – residential water
consumption accounts for approximately 66% of the City’s total supply (2007/2008).
Residential water consumption has previously been determined to be influenced by seasonal
changes and Water Demand Management (WDM) strategies such as water metering (compared
with unmetered homes), water restriction levels, water efficient devices and education (Inman
and Jeffrey, 2006; Mayer et al., 2004; Nieswaidomy, 1992). Although prior research in these
areas has occurred, it is well established that there is a requirement for specific country and
location based research due to different community attitudes and behaviours which can
influence the effectiveness of WDM strategies (Corral-Verdugo et al., 2002; Turner et al.,
2005). To evaluate the effectiveness of WDM strategies high quality data is required. The
development of smart metering technologies and end use analysis techniques allowed for the
acquisition of such data in this study.
6.2.4 Overview of Gold Coast End Use Study
The Gold Coast Water End Use (GCWSEU) Study commenced in 2007 as an ARC funded
collaborative research investigation by Griffith University, Gold Coast Water and the Institute
for Sustainable Future (University of Technology, Sydney). The purpose of this study was to
identify end use water consumption in Gold Coast homes and to evaluate the effectiveness of
Chapter 6: End use water consumption in households: impact of socio-demographic factors and efficient devices
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WDM strategies namely the application of water efficient devices and education as well as
understanding water use differences between varying socio-demographic groups. Smart
metering was implemented to ascertain end use water consumption data, to enable comparative
analysis between varying household socio-demographic clusters and to understand the water
saving potential of efficient devices. These aspects represent two objectives of the GCWSEU
study explored in this paper.
6.2.5 Engineered water efficiency
Engineered efficiency or the development of higher efficiency water using devices has seen
effective reductions in water consumption. In Tampa, USA Mayer et al. (2004) determined that
the retrofitting of water efficient devices can result in a reduction of up to 49.7% of water use
per capita; a highly significant reduction. Inman and Jeffrey (2006) report that the
comprehensive replacement of household appliances (such as showers, toilets and clothes
washers) with highly water efficient appliances can reduce indoor water consumption by
between 35-50%. Not only does this reduction in demand serve to preserve water supply
security for future generations but reduces the life cycle cost of potable water treatment and
distribution, as well as energy intensive wastewater treatment (Barrios et al., 2008; Mahgoub et
al., 2010) and ultimately the ecological footprint of the city or nation (Friedrich et al., 2009;
Hubacek et al., 2009).
6.2.6 Influences of socio-demographic factors
There are several previously reported socio-demographic factors that can influence water
consumption. The result of the socio-demographic variable investigations by the ARCWIS
(2002) indicated that owner occupied properties, higher income families and households with
swimming pools consumed more water for irrigation. Loh and Coghlan (2003) reported a strong
relationship between income level and outdoor water use. The occupancy and make up of
dwellings, lot size and the age of water using devices have also been found to influence water
consumption with larger lot sizes generally consuming more water (Mayer and DeOreo, 1999).
6.2.7 Research objectives
The objectives of this paper are to:
1. Determine a household and per capita water consumption end use break down for a sample
of Gold Coast households;
2. Explore the relationship between household stock survey efficiency rating clusters and
water end use consumption levels; and
Domestic End Use Investigation: WDM and Dual Reticulation, R.M. Willis (2010)
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3. Ascertain demographic information of water users and determine if socio-demographic
factors influence water consumption.
The multifaceted objectives of the GCWSEU study required the application of a mixed methods
research design to obtain the required data types.
6.3 Method
To achieve the desired objectives of the study, a mixed methods data collection procedure
including a stock survey of water using fixtures/appliances in households, end use water
consumption study and a questionnaire survey, were concurrently undertaken with 151
households on the Gold Coast City, Australia.
6.3.1 Mixed method study design
The study adopts a mixed method design through collecting, analysing and mixing quantitative
and qualitative research approaches and processes. This mixed methods approach allows the use
of multiple methods to address research objectives (Creswell and Plano-Clark, 2007). A mixed
method approach was embarked upon as an array of data types are required to meet the
developed research objectives. Namely, natural science data in the form of end use water
consumption data, quantitative statistical survey data for demographic information, quantitative
stock survey information, and, qualitative water behaviour data were required.
6.3.2 Sample
A sample of 151 homes was recruited across Gold Coast City, Australia, including the
Pimpama-Coomera and Mudgeeraba suburbs. As noted by Willis et al. (2009b), regions were
selected according to differing socio-demographic makeup. Comparative investigation of
demographic factors including household makeup and ownership status assisted in confirming
the selected regions. Age of infrastructure was also considered with all homes subsequently
being developed in the past five years (Willis et al., 2009b).
6.3.3 Water consumption end use study
The relationship between smart metering equipment, household stock inventory surveys and
flow trace analysis is shown in Figure 6-1. Essentially, a mixed method approach was used to
obtain and analyse water use data. Two aligned main processes were adopted: physical
measurement of water use via smart meters with subsequent remote transfer of high resolution
data; and documentation of water use behaviours and compilation of water appliance stock via
individual household audits and self-reported water use diaries.
Chapter 6: End use water consumption in households: impact of socio-demographic factors and efficient devices
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Figure 6-1 Schematic illustrating water end use analysis process
The collection of end use water consumption data requires the application of a smart metering
set-up. The GCWSEU study smart metering set-up includes high resolution Actaris CTS-5
water meters, 72 pulses per litre or a pulse every 0.014L of water used, connected to Aegis Data
Cell D data loggers which are set to collect pulse counts every ten seconds. Downloaded raw
data files were in the ASCII format, which were then modified into .txt files for subsequent
trace flow analysis.
End use data in .txt file form was analysed by Trace Wizard© software version 4.1. Stock
appliance audits were used to help identify flow trace patterns for each household. Once a
template was created for each household, data for a sampled two-week period was analysed.
Trace Wizard© software was used in conjunction with the stock appliance audits to analyse and
disaggregate consumption into a number of end uses including toilets, irrigation, shower,
clothes washer and taps (faucets). An MS Excel™ spreadsheet was generated as a final output
for a more detailed statistical trend analysis and the production of charts.
6.3.4 Questionnaire survey
Questionnaire surveys were developed to obtain socio-demographic information of each
household to allow for clustering and analysis between varying demographic indicators. Surveys
Domestic End Use Investigation: WDM and Dual Reticulation, R.M. Willis (2010)
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were distributed to each smart metered household with information entered into SPSS (i.e.
statistical analysis program).
6.3.5 Household appliance stock survey and water behaviour investigation
Household stock surveys have previously been undertaken to gain a snapshot of water
consuming devices in regions (Roberts, 2003). A household water audit was undertaken for the
GCREUS study to determine water using devices within the household, to assist in carrying out
end use data analysis with Trace Wizard©, and to obtain a qualitative understanding of when
people undertook certain water consuming activities in their home. A research officer visited
homes and noted down model and serial numbers for clothes washers, dishwashers and toilets;
determined the efficiency of water shower heads; the inclusion of tap flow restrictors and
recorded volumes of rainwater tanks (if applicable). The research officer also asked questions as
to when clothes washing or showering generally occurred, inquired about the number of
showers or baths, irrigation use and a whole range of other questions surrounding water use
behaviour within the home.
The Water Efficiency Labeling and Standards (WELS) website4 was consulted to obtain
relevant water usage volumes for different fixtures particularly clothes washers, shower heads
and dishwashers to assist in data analysis and to determine the relative water efficiency of
devices.
6.3.6 Water end use analysis and comparison
End use data analysis was undertaken with Trace Wizard© to establish when and where water
was being used in each home within the Gold Coast sample. Based on a winter 2008 data
collection for the sampled Gold Coast households (n=151) the average water consumption was
157.2 litres per person per day (L/p/d) (Willis et al., 2009). Figure 6-2 displays the end use
water consumption across the 151 households. Showering accounted for the highest use being
33% or almost 50 L/p/d with clothes washing being the next highest end use at 19% or 30 L/p/d.
Irrigation was much lower than previously conducted end use studies being only 18.6 L/p/d or
12% of total per capita consumption, this may have been due to higher rainfall over the
monitoring period.
4 http://www.waterrating.gov.au
Chapter 6: End use water consumption in households: impact of socio-demographic factors and efficient devices
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Figure 6-2 Average daily per capita consumption (L/p/d): combined sample (n=151)
An overview of water end use for the GCWSEU study and previous end use studies can be seen
in Table 6-1. The finalised end use values, socio-demographic survey data and water audit data
were all entered into SPSS to enable a comparative analysis between varying socio-
demographic groups and household water device efficiency.
Table 6-1 Comparison between national end use water consumption studies (Willis et al., 2009b)
Previous studies Present study End use category
Perth (2003) Melbourne (2005) Auckland (2007) Gold Coast (2008)
L/p/d Percent L/p/d Percent L/p/d Percent L/p/d Percent Clothes washer 42.0 13% 40.4 19% 39.9 24% 30.0 19% Shower 51.0 15% 49.1 22% 44.9 27% 49.7 33% Tap 24.0 7% 27.0 12% 22.7 14% 27.0 17% Dishwasher NA NA 2.7 1% 2.1 1% 2.2 1% Bathtub NA NA 3.2 2% 5.5 3% 6.5 4% Toilet (total) 33.0 10% 30.4 13% 31.3 19% 21.1 13% Irrigation (total) 180† 54% 57.4† 25% 13.9 8% 18.6 12% Leak (total) 5.0 1% 15.9 6% 7.0 4% 2.1 1% Other NA NA 0.0 0% 0.8 0% 0.0 0% Total Consumption
335.0 100% 226.2 100% 168.1 100% 157.2 100%
†Note: Irrigation volume per person calculated from provided volumes per household and end use break downs.
6.4 Results
6.4.1 Influence of socio-demographic factors
Analysis determined that a range of collected socio-demographic factors influenced end use
water consumption levels, namely, location of household, lot size, Rain Water Tank (RWT)
Clothes Washer
30.0L/p/d19.1%
Shower49.7 L/p/d
31.6%
Tap27.0L/p/d
17.2%
Dishwasher2.2L/p/d
1.4%
Bathtub6.5 L/p/d
4.2%
Toilet (total)21.1 L/p/d
13.4%
Irrigation (Total)
18.6L/p/d11.8%
Leak (Total)2.1L/p/d
1.3%
Average Daily Per Capita Consumption (L/p/day): Single+Dual (n=151)
Total = 157.2 L/p/d
Domestic End Use Investigation: WDM and Dual Reticulation, R.M. Willis (2010)
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ownership, household income and household characterisation. Some of these relationships are
explored in this paper and are presented succinctly below.
Socio-demographic region of households
Several regions in differing areas of the Gold Coast were selected to ensure that the combined
water end use sample was representative. For the purpose of the GCWSEUS study, four socio-
demographic groups in distinct regions were selected and compared: (a) low (Cassia Park:
n=42); (b) low to middle (Mudgeeraba: n=36); (c) middle (Crystal Creek: n=38); and (d) middle
to high (Coomera Waters: n=35). displays the end use water consumption for these four socio-
demographic regions.
Previous water consumption research indicates that individuals that are wealthier, older and live
in new and larger homes consume more (Kim et al., 2007; Kenney et al., 2008). Such findings
were not substantiated in this study. Figure 6-3 demonstrates that generally lower socio-
demographic groups tended to use slightly more water than those in higher socio-demographic
groups across most end use categories. One outlying variable to this trend is irrigation. Coomera
Water residents, the highest of the recorded socio-demographic regions, were the highest
consumers per capita for irrigation, using 27.84 L/p/d with Cassia Park, the lowest socio-
demographic group consuming the lowest irrigation volume of 12.07 L/p/d. This opposing trend
of higher socio-demographic region translating to higher irrigation end use consumption could
be attributed to lot size or higher concern for garden aesthetics.
Figure 6-3 Impact of socio-demographic area on end use water consumption
Lot size and rainwater tank ownership
The effect of lot size (total land area) and rainwater tank (RWT) ownership on outdoor
irrigation was examined (n=121). Figure 6-4 illustrates increased irrigation with increasing lot
Chapter 6: End use water consumption in households: impact of socio-demographic factors and efficient devices
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size for households without RWTs (n=86). This result is consistent with that found by Loh and
Coghlan (2003). Interestingly, houses with RWTs (n=35) actually decreased irrigation
consumption from the mains supply as lot sizes increased. Meaning that, irrigation was highest
for smaller lot sizes with RWTs with those of large lot sizes consuming the least. The reason for
this phenomenon is still unknown and may be due to error caused by a lower sample in the
higher lot size clusters. One hypothesis is that the larger lot owners may have invested in higher
volume RWT with pump features and irrigation lines whilst those in smaller lots may not utilise
their tanks since they are small with no pump facility making householders less inclined to use
this source of water. A larger sample size across all lot size clusters would be required to
confirm this hypothesis.
Figure 6-4 Impact of lot size and RWT installation on irrigation end use
Household Income
108 households stated the incomes of individuals within their residences on the survey. These
households were divided into three categories based on weekly household income to investigate
the influence of household income on water consumption. The categories were defined as: (a)
less than $1200 per week (n=31); (b) between $1200 and $2000 per week (n=45); and (c) more
than $2000 per week (n=36). Figure 6-5 indicates that as income increased, so does water
consumption. Interestingly, the water consumption of the middle to upper household income
clusters was very similar and no significant difference could be interpreted. Lower income
households were shown to consume approximately 8% less than the average water consumption
for the Gold Coast City sample (i.e. 157.2 L/p/d as per Table 6-1), however lower socio-
demographic profiles (which consider factors beyond income) were shown in Section 6.4.1. to
use more water for end uses other than irrigation – in this case, the lower irrigation component
leads to lower overall usage.
Domestic End Use Investigation: WDM and Dual Reticulation, R.M. Willis (2010)
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Figure 6-5 Impact of family income on water consumption
Household resident typology
The impact of household typology (i.e. resident makeup) on end use water consumption was
also investigated. Households (n=126) were divided into four categories, namely: (a) single
person (n=5); (b) couple (n=34); (c) small family with four or less people (n=64); and (d) large
family with more than four people (n=23). Total per capita consumption was 211.4 L/p/d, 183.5
L/p/d, 140.6 L/p/d and 135.6 L/p/d for household typologies a, b, c and d, respectively. Figure
6-6 indicates that there is a general decrease in consumption per capita as family size increases.
Clothes washer and toilet end use consumption oppose this trend with these end uses being
higher in large families than small families. This may be due larger families being more likely
to have very young children requiring extensive washing and a higher utilisation of the toilet
due to increased time spent at home.
Figure 6-6 Relationships between household resident typologies and water end use consumption
6.4.2 Stock efficiency versus end use consumption
Table 6-1 demonstrates that shower use and clothes washing account for the highest end uses of
water on the Gold Coast, being 33% and 19% of total average consumption, respectively.
Further analysis was undertaken to examine trends for water saving when considering the
engineered efficiency of water use devices.
Chapter 6: End use water consumption in households: impact of socio-demographic factors and efficient devices
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Influence of showerhead efficiency
Sample average per capita shower end use was 49.7 L/p/d or 32% of total water use which was
157.2 litres per household per day (L/hh/d). This was the highest water consuming activity on
the Gold Coast as often reported elsewhere. It is well established that the installation of high
efficiency, low flow showerheads can save considerable volumes of water (Mayer et al., 2004).
The Australia WELS requires products to be registered and labelled with their water efficiency
in accordance with the standard set under the national WELS and Standards Act 2005
(Commonwealth of Australia, 2008). These standards list that three star rated water efficient
showerheads (formerly AAA) use as little as 6-7 L/min, medium efficient showerheads (AA)
consume between 9-15 L/min and the standard non-efficient showerheads (A) can use as much
as 15-25 L/min. Different dwellings have a high variation in the efficiency of their showerheads
and often showerheads differ within households. Due to the variation of showerhead efficiencies
within dwelling bathrooms a weighting system was applied in this study. The weighting system
provided each bathroom showerhead with a rating as follows: (a) AAA rated showerheads
allocated a score of 5: (b) AA rated showerheads a rating of 3; and (c) A rated shower heads and
less a score of 1. Each dwelling total score was averaged (w) based on number of showerheads.
The weighting system allowed for the categorisation of households into three shower efficiency
clusters which match the AAA, AA and A, WELS ratings, namely Low, Medium and High
efficiency, Table 6-2 demonstrates the results.
Table 6-2 Showerhead efficiency cluster comparisons
Description Showerhead efficiency clusters Efficiency category Low Medium High
Weight range 5 ≤ w ≤ 4 4 ≤ w ≤ 3 3 ≤ w ≤ 1 No. of households in cluster (n=151) 59
(39%) 42
(27.8%) 50
(33.2%) No. of people in cluster (n=495) 181
(36.6%) 124
(25%) 190
(38.4%) Per capita shower consumption per day (L/p/d) 64.7
(1.93) 46.8
(1.39) 33.6 (1)
Household shower consumption per day (L/hh/d) 245.7 (2.38)
138.1 (1.34)
103.1 (1)
Per capita shower consumption per annum (kL/p/a) 23.6 (1.93)
17.1 (1.39)
12.3 (1)
Household shower consumption per annum (kL/hh/a) 89.7 (2.38)
50.5 (1.34)
37.6 (1)
Table 6-2 provides evidence that by changing low efficient showerheads (A) to high efficient
showerheads (AAA) in each household in the Gold Coast could result in annual per capita water
savings of 11.3 kL or 48%. Annual household savings were slightly higher being 52.1 kL or
58%. The ratio of savings between the High and Medium categories (1.34-1.39) and High to
Low categories indicates that a changeover to AAA rated showerheads yields far greater
savings. The savings identified herein were at the higher end of the range determined in other
studies such as Melbourne at 27%, Perth at 22% and in South-east Queensland (SEQ) at 31-54%
Domestic End Use Investigation: WDM and Dual Reticulation, R.M. Willis (2010)
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(Roberts, 2005; Loh and Coghlan, 2003). As detailed in a later section, showerhead retrofits
represent one of the least cost water demand management initiatives available to water
businesses and government.
Influence of clothes washer efficiency
The end use water consumption for clothes washing for the Gold Coast sample was determined
as 30 L/p/d. Clothes washing consumption was the second highest water use after showering.
WELS star rating for clothes washers was based on loading type, load capacity, water
consumption per wash, brand and model name. The Commonwealth of Australia (2008) state
that water efficient washing machines can use a third of the water required by an inefficient
model. The WELS website details the rate of water consumption per wash for each brand and
model of clothes washing machine on the Australian market. Household water audits
established the specific model details (i.e. brand, model, year, etc) to assist in determining
clothes washer load volumes. Household clothes washers were allocated efficiency categories
based on per load water consumption; Table 6-3 demonstrates the results of the comparative
clothes washer water end use levels for each efficiency cluster category.
Table 6-3 Clothes washer efficiency comparisons
Description Clothes Washer Efficiency Clusters Efficiency category Low Medium High
Star rating range 1 – 2.5 3 – 3.5 4 – 6 Category (L/wash) 120 - 170 80 - 119 40 – 79
No. of households in cluster (n=148) 38 (26%)
40 (27%)
70 (47%)
No. of people in cluster (n=486) 148 (30%) 119 (25%) 219 (45%) Per capita clothes washer consumption per day
(L/p/d) 53.0
(3.68) 36.3
(2.52) 14.4 (1)
Household clothes washer consumption per day (L/hh/d)
206.4 (4.57)
108.0 (2.51)
45.2 (1)
Per capita clothes washer consumption per annum (kL/p/a)
19.4 (3.66)
13.3 (2.52)
5.3 (1)
Household clothes washer consumption per annum (kL/hh/a)
75.3 (4.57)
39.4 (2.51)
16.5 (1)
Table 6-3 demonstrates that replacing a low efficiency clothes washer with a high efficiency
model can save a staggering 14.1 litres per person per annum (L/p/a) or 73%. Annual household
savings are also equally significant at 58.8 kL. It should be noted that these savings are
significantly higher than those listed on the WELS web site and are higher than those previously
identified in Melbourne and SEQ. Replacing traditional washing machines with those with a
high star rating is a highly recommended water demand management activity.
Influence of rainwater tanks on irrigation end use
Irrigation has long been identified as a high water end use, accounting for up to 54% in some
regions (Loh and Coghlan, 2003). RWTs are considered by some water demand management
Chapter 6: End use water consumption in households: impact of socio-demographic factors and efficient devices
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professionals as an effective way to reduce the demand on potable supplied water. The Gold
Coast end use study included a number of households (n=39; 25.8%) with an installed RWT. It
should be noted that these RWT were not internally plumbed and were mainly for outdoor use
purposes only (i.e. irrigation, pool top-up, etc.). Whilst RWT metering was not included in the
scope of this study, household water audits identified whether a tank was installed, enabling
comparison between irrigation end use volumes for households with or without a RWT (Table
6-4).
Table 6-4 Rainwater tank cluster comparisons
Description Rainwater Tank Clusters
Category Households with RWT
Households without RWT
No. of households in cluster (n=151) 39 (25.8%)
112 (74.2%)
No. of people in cluster (n=495) 114 (23%)
381 (77%)
Per capita irrigation consumption per day (L/p/d) 10.1 (1)
19.6 (1.94)
Household irrigation consumption per day (L/hh/d) 29.6 (1)
66.6 (2.25)
Per capita irrigation consumption per annum (kL/p/a) 3.7 (1)
7.2 (1.94)
Household Irrigation consumption per annum (kL/hh/a)
10.8 (1)
24.3 (2.25)
Table 6-4 provides evidence that the introduction of a RWT can significantly impact on
irrigation water end use consumption. The installation of a RWT can result in an annual
household saving of 13.5 kL. Seasonal variations need to be explored in future research to
examine whether this saving could be higher. The study herein provides some evidence to the
argument that RWT may be an effective strategy where water supply security is not guaranteed.
Given that RWT installations are potentially more expensive than other options capital payback
periods need to be explored.
Combined household efficiency savings
The combined influence of introducing water efficient showerheads, clothes washers and
installing RWTs was modelled to estimate total potential household savings by
retrofitting/installing to higher efficiency appliances/fixtures. The estimated savings, resulting
from the introduction of this array of demand management measures, amounted to an average
annual household water consumption reduction of 38.6% or from 512.2 L/hh/d to 322.1 L/hh/d.
While these are significant water savings, it is considered prudent for both consumers and water
managers to determine monetary aspects. Additionally, whilst outside the scope of this paper, in
the age of climate change mitigation, the energy implications of WDM decisions should also be
investigated as water savings may come at a higher energy cost.
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Financial benefits of efficient appliances
Often the understanding of relative water savings attributed to water efficient devices is not
enough to encourage consumers to outlay the capital cost to upgrade fixtures. Information about
the payback period associated with upgrading appliances is another way of displaying
information to encourage uptake. Based on the 2008/2009 financial year water billing price (i.e.
A$(AUD) 1.87/kL) the retrofitting of a low to high efficiency showerhead can potentially
deliver an annual water consumption saving of A$97 for Gold Coast residential households.
This increases to A$175 by 2018 which equates to a A$1331 cumulative saving per household
over this period (A$ 1.87/kL, 10% annual increase, 3% discount factor, N=10 years). Based on
a A$60 capital cost for the supply and installation of water efficient showerheads, a six (6)
month payback period was determined. This is an extremely good payback period and provides
evidence to support the recent Gold Coast Water and Queensland Government strategies to
retrofit appliances across SEQ in the recent drought (e.g. GCW & SEQ Home Water wise
Service).
Replacement of low efficiency washing machines to those with higher efficiency also has the
potential to deliver annual water savings of A$110 in 2009, increasing to A$199 in 2018. This
equates to a cumulative saving of A$1510 per household over this period. Hence, a 6.5 year
payback period was calculated based on a conservative capital cost of A$900 for a water
efficient washing machine. Again, this represents a reasonable payback period supporting the
upgrade of washing machines.
The use of RWTs could potentially deliver an annual water consumption saving of A$25 in
2009 increasing to A$135 in 2033 equating to a A$1660 cumulative saving per household over
this period (A$1.87/kL, 10% annual increase, 3% discount factor, N=25 years). Based on a
A$1200 capital cost for a 2000-4000L RWT a 21 year payback period was determined. This
payback period is high for the average homeowner, providing evidence to the argument that
RWT installation that are not internally plumbed, is not low hanging fruit in the least cost
planning framework. Understanding payback periods for the replacement of efficient water use
devices provides important information to allow consumers to make economically informed
decisions. These payback periods can also help support the introduction, or otherwise, of rebate
schemes targeting the highest water savings at a reasonable price as part of a broader
consideration of the social environmental and economic cost savings to the utility (through
reduced pumping and treatment as well as lower infrastructure upgrade costs) as well as the
consumer in a total resource cost approach to option evaluation (White et al., 2008).
Chapter 6: End use water consumption in households: impact of socio-demographic factors and efficient devices
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6.5 Conclusion
Smart metering has enabled the collection of highly accurate end use water consumption data.
The mixed method acquisition of this data in association with socio-demographic and stock
survey information, allowed for the relationship between these factors and individual water end
uses to be revealed. As discussed, socio-demographic factors such as household income,
household resident typologies, lot size and RWT ownership, were examined in this study and
had an influence on relevant end uses. End use data demonstrated that actual water savings
associated with the installation of efficient water use devices was generally at the higher end of
ranges reported in previous research investigations. This may be due to the extreme drought
conditions experienced in SEQ in 2008 influencing water consumption habits or a range of other
contributing factors. The payback period of showerheads occurs within half a year or less, while
clothes washer and RWT payback periods were determined as 6.5 and 21 years respectively.
These findings support the continuation of rebates particularly for showerheads and clothes
washers.
6.6 Acknowledgements
The GCWEUS study is conducted through a larger ARC collaboration. The Institute for
Sustainable Futures, University of Technology, Sydney; Wide Bay Water and the Queensland
Water Directorate are acknowledged for their involvement in the research collaboration.
6.7 References
ARCWIS, 2002. Perth domestic water- use study household ownership and community attitudinal analysis. NWS. Australian Research Centre for Water in Society CSIRO Land and Water.
Barrios, R., Siebel, M., van der Helm, A., Bosklopper, K., Gijzen, H. 2008. Environmental and financial life cycle impact assessment of drinking water production at Waternet. Journal of Cleaner Production 16, 471-476.
Britton, T., Cole, G., Stewart, R., Wisker, D., 2008. Remote diagnosis of leakage in residential households. Journal of Australian Water Association 35 (6), 89-93.
Commonwealth of Australia, 2008. Water Efficiency Labelling and Standards Scheme: WELS Products. http://www.waterrating.gov.au/products/index.html.
Corral-Verdugo, V. Bechtel, R., Fraijo-Sing, B., 2002. Environmental beliefs and water conservation: An empirical study. Environmental Psychology 23, 247–257.
Creswell, J.W., Plano Clark, V.L., 2007. Designing and conducting mixed methods research. USA. Sage Publications, Inc.
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Dvarioniene, J., Stasiskiene, Z. 2007. Integrated water resource management model for process industry in Lithuania. Journal of Cleaner Production 15, 950-957.
Friedrich, E., Pillay, S., Buckley, C.A. 2009. Carbon footprint analysis for increasing water supply and sanitation in South Africa: a case study. Journal of Cleaner Production 17, 1–12.
Giurco, D., Bossilkov, A., Patterson, J., Kazaglis, A. 2010. Developing industrial water reuse synergies in Port Melbourne: cost effectiveness, barriers and opportunities. Journal of Cleaner Production, doi:10.1016/j.jclepro.2010.07.001.
Goulburn Mulwaree Council, 2008. Council removes signs but Level 3 Water Restrictions remain. http://goulburn.local-e.nsw.gov.au/news/ pages/7901.html.
Hubacek, K., Guan, D., Barrett, J., Wiedmann, T. 2009. Environmental implications of urbanization and lifestyle change in China: Ecological and water footprints. Journal of Cleaner Production 17, 1241-1248.
Inman, D., Jeffrey, P., 2006. A review of residential water conservation tool performance and influences on implementation effectiveness. Urban Water Journal 3 (3), 127- 143.
Kenney, D., Goemans, C., Klein, R., Lowrey, J., Reidy, K., 2008. Residential water demand management: lessons from Aurora, Colorado. Journal of the American Water Resources Association 44 (1), 192 – 207.
Kim, S.H., Choi, S.H., Koo, J.K., Choi, S.I., Hyun, I.H., 2007. Trend analysis of domestic water consumption depending upon social, cultural, economic parameters. Water Science and Technology: Water Supply 7 (5-6), 61-68.
Krozer, Y., Hophmayer-Tokich, S., van Meerendonk, H., Tijsma, S., Vos, E. 2010. Innovations in the water chain – experiences in The Netherlands. Journal of Cleaner Production 18, 439-446.
Loh, M., Coghlan, P., 2003. Domestic Water Use Study. Perth. Water Corporation.
Mahgoub, M.E.M., van der Steen, N.P., Abu-Zeid, K., Vairavamoorthy, K. 2010. Towards sustainability in urban water: a life cycle analysis of the urban water system of Alexandria City, Egypt. Journal of Cleaner Production 18, 1100–1106.
Mayer, P., DeOreo, W., Towler, E., Martien, L., Lewis, D., 2004. Tampa Water Department residential water conservation study: The impacts of high efficiency plumbing fixture retrofits in single-family homes. Tampa. Aquacraft, Inc Water Engineering and Management.
Mayer, P. W., DeOreo, W. B., 1999. Residential End Uses of Water. Boulder, CO. Aquacraft, Inc. Water Engineering and Management.
Moore, T., 2008. Level six restrictions here to stay. Brisbane. http://www.brisbanetimes.com.au/articles/2008/01/10/1199554825143.html.
Nieswaidomy, M.L., 1992. Estimating urban residential water demand: effects of price structure, conservation, and education. Water Resources Research 28, 600-615.
Partzsch, L. 2009. Smart regulation for water innovation – the case of decentralized rainwater technology. Journal of Cleaner Production 17, 985-991.
Roberts, P., 2003. Yarra Valley Water 2003 Appliance Stock and Usage Patterns Survey. Melbourne. Yarra Valley Water.
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Roberts, P., 2005. Yarra Valley Water 2004 Residential End Use Measurement Study. Melbourne. Yarra Valley Water.
Stewart, R.A., Willis, R., Giurco, D., Panuwatwanich, K. and Capati, G. 2010. Web based knowledge management system: linking smart metering to the future of urban water planning. Australian Planner, 47 (2), 66-74.
Turner, A., White, S., Beatty, K., Gregory, A., 2005. Results of the largest residential demand management program in Australia. Institute for Sustainable Futures, University of Technology, Sydney. Sydney Water Corporation, Level 16, 115-123 Bathurst Street, Sydney, NSW.
White, S., Fane, S.A., Giurco, D. & Turner, A.J. 2008. Putting the economics in its place: decision-making in an uncertain environment, in C. Zografos and R. Howarth (eds), Deliberative Ecological Economics, Oxford University Press, New Dehli, India, pp. 80-106.
Willis, R., Stewart, R., Panuwatwanich, K., Capati, B., Giurco, D., 2009b. Gold Coast Domestic Water End Use Study. Journal of Australian Water Association 36 (6). September 2009.
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Chapter 7
Quantifying the influence of environmental and water conservation attitudes on household end use water
consumption
This chapter is a reformatted version of a peer-reviewed article completed by the author, in-
press (accepted March 2011) for publication in the Journal of Environmental Management,
Elsevier.
7.1 Abstract
Within the research field of urban water demand management, understanding the link between
environmental and water conservation attitudes and observed end use water consumption has
been limited. Through a mixed method research design incorporating field-based smart metering
technology and questionnaire surveys, this paper reveals the relationship between environmental
and water conservation attitudes and a domestic water end use break down for 132 detached
households located in the Gold Coast, Australia. Using confirmatory factor analysis, attitudinal
factors were developed and refined; households were then categorised based on these factors
through cluster analysis technique. Results indicated that residents with very positive
environmental and water conservation attitudes consumed significantly less water in total and
across the behaviourally influenced end uses of shower, clothes washer, irrigation and tap, than
those with moderately positive attitudinal concern (n=78; 169.0L/p/d). The paper concluded
with implications for urban water demand management planning, policy and practice.
7.2 Introduction
An escalating demand on potable water resources resulting from increasing populations,
droughts and unpredictable weather patterns due to climate change is commonplace in many
parts of the world (Bates et al., 2008; Commonwealth of Australia, 2008c). As a result, the
sustainable management of urban water has become imperative, particularly for countries prone
to severe droughts such as Australia. Australia receives the lowest average annual rainfall of all
inhabited continents and is experiencing strong population growth in urban areas (Birrell et al.,
Chapter 7: Quantifying the influence of environmental and water conservation attitudes on household consumption
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2005; Commonwealth of Australia, 2008b). In response a range of sustainable water
management practices and principles have been introduced to ensure the secure supply of urban
water. Notably, water demand management (WDM) initiatives are utilised to assist in shifting
consumers towards sustainable water consumption behaviour. WDM is defined as the practical
‘development and implementation of strategies aimed at influencing demand’ (Savenije and van
der Zaag, 2002, pp. 98). It is characterised by reducing average water consumption to ensure
efficient and sustainable use of the resource (Tate, 1993; Deverill, 2001; Brooks, 2002; Brooks,
2006). WDM measures are generally the most sustainable solutions across environmental, social
and economic factors, in the range of options presented for water supply security (White et al.,
2007). WDM measures focus on reducing end use consumption hence offsetting the need for
additional water supply and wastewater treatment measures which are costly and can be
environmentally and socially detrimental. Initiatives for WDM are focused on supplying tools,
mechanisms and knowledge to enable residents to continually reduce their potable water
consumption (through the reduced use of water-using devices or uptake of water-efficient
devices). The WDM approach relies heavily on consumers to understand how to reduce their
water consumption and to apply this understanding to everyday activities to consume
sustainably.
Past research has determined that water consumption within households is dependent on
numerous factors, which include: the number of people in the house, the age of residents,
education levels of residents, lot size of properties, residents’ income, efficiency of water
consuming devices (i.e. clothes washers, shower heads, tap fittings, dishwashers and toilets) and
the attitudes, beliefs and behaviours of consumers (Nieswaidomy and Molina, 1989; Renwick
and Archibald, 1998; Mayer and DeOreo, 1999; Renwick and Green, 2000; Inman and Jeffrey,
2006).
The pricing of water was initially predicted to influence consumption but this belief has more
recently been dispelled, with research demonstrating that in most cases residential water
demand is largely price inelastic because of its low relative cost when compared to other life
essentials (Worthington and Hoffmann, 2008; Barrett 2004). Barrett’s (2004) investigation of 30
residential water price demand studies revealed that most indicated price inelasticity, with
evidence that only very large external users being more likely to be sensitive to price changes.
Earlier end use studies have demonstrated that households with very high incomes consume
more water externally while, the variation of internal water consumption remains similar and is
not statistically significant between income levels (Mayer and DeOreo, 1999; Loh and Coghlan,
2003). External consumption is the end use detailed to be most effected by income and the cost
of water (Mayer and DeOreo, 1999). Mayer and DeOreo (1999) have reported a positive
relationship between larger lot sizes and higher outdoor water consumption in the USA while,
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Loh and Coghlan (2003) found that this was not the case in Australia. In fact there was no
evidence of a relationship between irrigable area and external household usage present (Loh and
Coghlan, 2003). Elements which were found to increase external water use in both studies were
the ownership of automated irrigation systems and swimming pools (Mayer and DeOreo, 1999;
Loh and Coghlan, 2003).
In relation to WDM, the last group of factors (i.e. attitudes, beliefs and actual behaviours of
consumers) are particularly relevant as water management initiatives often include pressure on
residents to reduce household water consumption through undertaking more sustainable water
consumption practices. Shifting residents toward sustainable water consumption practices thus
requires the instilling of awareness, understanding and appreciation of the environment and
water. Establishing a connection between attitudes and beliefs concerning water and the
environment and their relationship on actual water consumption behaviour has been undertaken
previously (Nancarrow et al., 1996; Hassell and Cary, 2007). However, empirical studies that
quantify the nature of such a relationship are still largely lacking within the current body of
knowledge. To fill this gap, the herein described research was aimed to empirically investigate
how attitudes and beliefs influence urban end use water consumption behaviour.
The objectives of this research include:
Developing measurable research propositions relating to attitudes and domestic end use
water consumption behaviour;
Undertaking a field-based smart metering study and subsequent flow trace analysis
process to disaggregate domestic water end uses for a statistically significant sample;
Exploration of the characteristics of consumers with respect to their attitudes towards the
environment and water conservation;
Investigation on the relationship between a confirmed taxonomy of attitudinal constructs
and end use water consumption; and,
Confirming the environmental and water conservation attitudes of residential households
that significantly affect behaviourally influenced (i.e. life style choice such as longer than
required showers) end use water consumption levels.
Meeting these objectives will enable water professionals to effectively target WDM education
and awareness programs, thus yielding higher water savings for such initiatives. Ultimately,
research outcomes could be subsequently integrated into national water planning and
management strategies to enhance long term WDM practices. The paper presents the theoretical
background relevant to understanding the attitudes and behaviours that affect domestic water
consumption and conservation. Following this is a description of research propositions. The
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adopted research method is detailed along with data analysis and results. Key findings are
discussed with the paper concluding by deliberating on managerial implications.
7.3 Theoretical Background
7.3.1 Water consumption attitudes and behaviour
Determining motives for saving water are key when designing educational urban water saving
strategies; hence at the outset, an understanding of consumption and attitudes towards water is
vital (Corral-Verdugo et al., 2003). It has been previously established that the attitudes and
beliefs of consumers directly impact on water use behaviours which are closely linked to water
demand (Hassell and Cary, 2007). To understand the embodiment of people’s attitudes and
behaviour, and their association with water consumption, Ajzen and Fishbein’s (1980) theory of
reasoned action was adopted as a point of departure.
Ajzen and Fishbein’s theory conceptualises the linkages between beliefs, attitudes, perceived
social norms and behaviours by building on the expectancy value theory through the
incorporation of normative social influence on behavioural intention (Hassell and Cary, 2007).
This theory was employed to assist in the establishment of a baseline model to undertake
attitudinal analysis. Several earlier research studies adopted the same approach to investigate
attitudes and their impact on water consumption behaviour. For example, Syme and Nancarrow
(1992) and Po et al. (2005) have applied Ajzen and Fishbeins’ theory of reasoned action to
explain the extent to which intended behaviour could predict actual consumer responses to
water supply systems. When considering risks and other social elements, the model was
particularly useful for predicting behaviour associated with the delivery of potable water
(Hassell and Cary, 2007).
To better understand and capture the above attitudinal concept, two main factors were identified
as having an influence on water consumption from a review of earlier research, being: (1)
Concern for Environment (CE); and (2) Water Conservation Awareness and Practice (WC).
Following Nancarrow et al. (1996), these two primary attitudinal factors can be used to assess
the ‘way in which people think about water’. Past research on the effect of such attitudinal
factors on water consumption is examined in the following sections.
Concern for environment
The link between general environmental beliefs and conservation behaviour has been detailed
by DECC (2007), Kordiatis et al. (2004) and Corral-Verdugo et al. (2003). Surveys undertaken
by Kordiatis et al. (2004) determined that attitudes towards environmental issues were in fact
reliable predictors of environmental behaviour. Corral-Verdugo et al. (2003), drawing on the
instrument commonly used to measure general environmental beliefs, namely, the New
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Environment Paradigm-Human Exception Paradigm (NEP-HEP), exclusively investigated the
relationship between general environmental beliefs and water conservation behaviour. In
Sonora, Mexico, surveys were undertaken to establish environmental beliefs in general as well
as environmental beliefs specific to the connection of water as a natural resource, along with
demographic details with water consumption recorded and estimated through a diary approach
(Corral-Verdugo et al., 2003). The results supported the hypothesis that general environmental
beliefs significantly influence domestic water consumption behaviour when beliefs and
behaviours are assessed at a corresponding level of specificity (Corral-Verdugo et al., 2003).
More recently, Gilg and Barr (2006) carried out a study of 1,265 households in Devon, UK
exploring the relationship between environmental attitudes and behaviours focussing on total
urban water use as the primary interest. The research examined if there were substantive links
between environmental actions and water saving behaviour to determine behavioural variations
associated with environmental activist classification (Gilg and Barr, 2006). Results indicated
that committed environmentalists and main stream environmentalists were most likely to engage
in energy and water saving activities regularly. Recent longitudinal research by DECC (2007),
assessing public attitudes to the environment including water related issues across Australia, has
determined a growing concern for environmental and water issues with respondents identifying
a willingness to undertake sustainable actions or behaviours.
The review of prior research assisted in establishing a derived factor representing environmental
concern consisting of eight indicators being: protection of natural environment for future
generations; community responsibility for reducing water consumption; concern for
environmental problems; joint responsibility of government and community to ensure water
security; acknowledgement of water being a valuable resource; acknowledgement of one’s role
in creating a sustainable water future; valuing recycling, composting and other environmentally
sustainable activities; and acknowledgement of humans role as caretaker for environment.
Details of these indicators along with their associated references are presented in Table 7-1.
These listed elements are refined and confirmed in the latter part of the paper to ensure they are
appropriate measurable indicators of the derived environmental concern factor.
Water conservation awareness and practice
Water conservation awareness and practice involves understanding the efficiency, opportunities
and impacts of certain water saving activities as well as the desire to continually reduce
consumption (Nancarrow and Syme, 1989; CSIRO, 2002; Gilg and Barr, 2006; Heinrich, 2007).
Water conservation relating to concern for water as a scarce resource was investigated in a
major study by Nancarrow et al. (1996), who determined from the investigation that the ways
people think about water does not predict their water consumption, contradicting the findings
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from other studies in the field (Middlestadt et al., 2001; CSIRO, 2002). Nancarrow and
colleagues reasoned that this outcome may be due to the adopted method of recording water
consumption data at a household level through a diary approach, while survey data was
collected as individual responses.
Table 7-1 Measurement items for concern for environment factor
Concern for environment (CE)
Code Measurement item Description References
CE1 Protection of natural environment for future generations
Examining the way in which individuals view the importance of protecting the natural environment.
Corral-Verdugo et al. (2003); CSIRO (2002).
CE2 Community responsibility for reducing water consumption
Enquiry of community responsibility for conserving water sources by reducing consumption.
CSIRO (2002); Nancarrow (2002); Corral-Verdugo et al. (2003); DECC (2007).
CE3 Concern for environmental problems
Investigation of care or concern for the general environment
Hurlimann (2008) ; Corral-Verdugo et al. (2003); DECC (2007).
CE4 Joint responsibility of government and community to ensure water security
Inquest into water security being the responsibility of both the government and the community.
Nancarrow (2002); DECC (2007).
CE5 Acknowledge water as being a valuable resource
Query of the scarcity of water and acknowledgement of its value as a resource.
CSIRO (2002); Hurlimann (2008) ; Nancarrow et al. (1996); Nancarrow (2002); Corral-Verdugo et al. (2003).
CE6 Acknowledge role in creating a sustainable water future
Comprehension of the role of people as consumers and the need to use resources sustainably to ensure availability in the future.
Hurlimann (2008)
CE7 Valuing recycling, composting and other environmentally sustainable activities
Evaluation the value of recycling, composting and other environmentally sustainable activities to consumers.
Gilg and Barr (2006); DECC (2007); Korfiatis et al. (2004).
CE8 Acknowledge humans role as caretaker for environment
Viewpoint on humans being responsible for sustaining the environment in its natural form
Corral-Verdugo et al. (2003); Syme et al. (2000).
Middlestadt et al. (2001) similarly explored the relationship of knowing or having the
knowledge on how to conserve water and whether this translated into actual behaviour. The
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research determined that students who were taught and understood water conservative
behaviours more regularly performed these behaviours. The CSIRO (2002) carried out an
extensive study in Perth, utilising both diary and end use monitoring methods, to determine
attitudes of consumers and water consumption with investigations indicating that attitudinal
variables affect external or outdoor water consumption (CSIRO, 2002). Unfortunately, the link
between attitudinal factors and indoor end use water consumption was not reported on. Hence,
this study set out to examine the influence of attitudes on indoor and outdoor domestic water
end use.
Through an extensive review of literature, nine indicators were uncovered that serve to represent
the derived water conservation awareness and practice factor, being: awareness of
opportunities to save water in household; awareness of the water saving benefits of retrofitting
to water efficient fixtures and appliances; water meter reading competency; monitoring of water
use; awareness of the relationship between behaviour and water consumption; water saving
know-how; perception on efficiency of household water use practices/behaviours; seeking
continuous savings in water consumption over the longer term; and regular water meter reading.
These items are described succinctly in Table 7-2, and are assessed in the latter part of the paper
to ensure they are appropriate measurable indicators of the derived water conservation and
practice factor. Once confirmed, this, along with the environmental concern factor were
subsequently utilised to determine the effect of attitudes on domestic end use water
consumption.
7.3.2 Water end use monitoring
Effective water monitoring techniques are essential for understanding domestic water
consumption behaviour (Stewart et al., 2010). Many water authorities provide information on
how to read a water meter to consumers with the belief that knowledge of water consumption
will assist in conserving water. Determination of water consumption within a household,
however, requires specific knowledge on how, where, when and who consumes water within
them. Initially, determining such elements of consumption relied on the honesty and vigilance
of residents through diary recording methods. Water consumption studies utilised a diary
recording method to establish end water usage. The diary method involves a member of the
household noting down every water consuming event i.e. a shower, toilet flush or tap use. The
nominated recorder would also note who carried out the event and the event duration (CSIRO,
2002; Cordell et al., 2003). Issues such as the subjectivity of measurements, consistency of
people to record all information and the influence on behaviour through recording methods led
to the development of a less intrusive and more accurate measurement method in the form of
smart metering (Cordell et al., 2003). The development of smart metering technology has
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eliminated the error of the older end use recording methods being, diary records, resulting in
accurate records of end use water consumption within residential households.
Table 7-2 Measurement items for water conservation awareness and practice factor
Water conservation awareness and practice (WC)
Code Measurement item Description References
WC1 Awareness of opportunities to save water in household
Understanding of the numerous opportunities or practices to conserve water in the household.
Nancarrow and Syme (1989); CSIRO (2002); Gilg and Barr (2006); DECC (2007); Mayer and DeOreo (1999).
WC2 Awareness of the water saving benefits of retrofitting to water efficient fixtures and appliances
Examining the understanding of the reduction in water use which can be achieved through the application of water efficient fixtures and devices.
Nancarrow and Syme (1989); CSIRO (2002); Heinrich (2007); Mayer and DeOreo (1999).
WC3 Water meter reading competency
Query of the ease of reading the household water meter and understanding the values.
Gold Coast Water (2008a)
WC4 Monitoring of water use Analysis of perception of knowing and monitoring how much water is used.
CSIRO (2002); DECC (2007); Heinrich (2007).
WC5 Awareness of the relationship between behaviour and water consumption
Enquiry on the relationship between water use activities and actual water consumption.
Nancarrow (2002); Gilg and Barr (2006); DECC (2007).
WC6 Water saving knowhow Examination of the application of activities to save water in the home.
Middlestadt et al. (2001); CSIRO (2002); DECC (2007).
WC7 Perception on efficiency of household water use practices/behaviours
Exploring the perceptions of respondents on their practices or behaviours which contribute to being an efficient water user.
CSIRO (2002); Gilg and Barr (2006).
WC8 Seeking continuous savings in water consumption over longer term
Determination on water conservation being a long or short term consideration.
Syme et al. (2000); CSIRO (2002); DECC (2007).
WC9 Regular reads water meter Need work around understanding & monitoring consumption with use of water meters.
Gold Coast Water (2008a)
The advent of smart water metering enabled water consumption to be monitored at an end use
level, resulting in the identification of individual water use events, such as shower, toilet
flushing, tap use or irrigation, through the use of appropriate software (Willis et al., 2009b).
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Smart metering involves the application of a high resolution water meter and a data logger to
obtain a continuous record of accurate water consumption data. This smart metering approach
has been utilised in many water end use studies conducted worldwide. Details of the results of
the more significant end use studies conducted throughout the world are presented in Table 7-3.
Table 7-3 Results from domestic end use studies
Previous studies USA (1999)
Mayer & DeOreo
Perth (2003) Loh & Coghlan
Melbourne (2005) Roberts
Auckland (2007) Heinrich
L/p/d Percent L/p/d Percent L/p/d Percent L/p/d Percent Clothes washer 56.8 8.7% 42.0 13% 40.4 19% 39.9 24% Shower 43.9 6.8% 51.0 15% 49.1 22% 44.9 27% Tap 41.3 6.3% 24.0 7% 27.0 12% 22.7 14% Dishwasher 3.8 0.6% NA NA 2.7 1% 2.1 1% Bathtub 4.4 0.7% NA NA 3.2 2% 5.5 3% Toilet 70 10.8% 33.0 10% 30.4 13% 31.3 19% Irrigation 381.6 58.7% 180† 54% 57.4† 25% 13.9 8% Leak 36.0 5.5% 5.0 1% 15.9 6% 7.0 4% Other 12.5 1.9% NA NA 0.0 0% 0.8 0% Total Consumption
650.3 100% 335.0 100% 226.2 100% 168.1 100%
†Note: Irrigation volume per person calculated from provided volumes per household and end use break downs.
Table 7-3 shows that in the Australia-Pacific region, the highest residential end uses are
showers, clothes washing, irrigation, toilet and tap use (Loh and Coghlan, 2003; Roberts, 2005;
Heinrich, 2007). These earlier studies established end use water consumption in their respective
regions and undertook analysis exploring the differences in end use consumption due to the
influence of socio-demographic variables. These studies, however, did not demonstrate or
provide any statistical indication of the influence of the abovementioned attitudinal factors on
various types of end use water consumption.
Understanding water consumption at the end use level is critical due to the fact that overall
domestic water consumption is made up of different water end use events. Broadly, water use
can be categorised into two main areas: non-discretionary and discretionary end uses
(ACTCOSS and CCSERAC, 2003). Traditionally, non-discretionary water use is defined as the
water used within the house to meet daily consumption and sanitation needs (e.g. shower,
clothes washing); whereas discretionary end uses are additional non-essential water use
activities (e.g. irrigation, pool use). However, lifestyle changes towards over consumption have
shifted many essential water end uses to include a large discretionary component, where use can
be well beyond what is required or considered publically acceptable for the activity. For
example, showering is now often utilised as a leisure or relaxation activity rather than simply
being used for sanitation needs. This behavioural shift epitomises the ‘Human Exception
Paradigm’, a belief that humans are above nature and therefore do not have to regard the
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environment when they consume resources (Bechtel et al., 1999). Therefore, this research
argues that discretionary water end uses should refer to those end use events that are likely to be
dependent and influenced by the lifestyle and behaviour of an individual. While certain volumes
of use are required for basic sanitation needs in shower, clothes washing and tap end uses, usage
above and beyond a reasonable sanitation requirement is argued to be discretionary. The World
Health Organization (WHO) stipulates that basic long term sustainable water consumption for
emergencies requires between 40 to 70 litres per person per day (L/p/d) for personal drinking,
sanitation and additional activities such as house cleaning, growing food and waste disposal
(WHO, 2005). A detailed investigation into basic water requirements to meet human needs by
Gleick (1996) also determined that 50 L/p/d of clean water is a fundamental human right. While
everyday living and consumption in a developed country cannot be based on WHO guidelines,
these figures emphasise that modern households in developed nations consume far more than
what is reasonably required for basic sanitation and consumption needs. Based on the core end
use categories mentioned above, irrigation, shower, tap, and clothes washing could be
considered uses that have a significant discretionary component, and toilet non-discretionary
when considering this refined definition of discretionary end uses (i.e. toilets are a fixed
consumption end use with limited behavioural influence). Leakage is not considered
discretionary or non-discretionary as this use is not a basic need nor is it influenced by
behaviour.
7.3.3 Research propositions
It is evident from the preceding sections that several investigations have established the
importance of environmental and water conservation attitudes on consumption behaviour. Most
demonstrate that positive attitudes and commitment towards the environment and water
conservation result in undertaking sustainable water conservation behaviours which, in turn,
results in lower water consumption. Hence, the following research proposition was developed:
Proposition 1: Households with higher levels of environmental concern and positive
attitudes towards water conservation will have significantly lower levels of total water
consumption.
In addition, since smart metering techniques allow for the accurate recording of water
consumption in specific end use categories, the relationships between behavioural attitudes and
various household end uses was further examined. Theoretically, because certain water
consumption end uses tended to be highly influenced by attitudes and behaviour, additional
propositions were formulated to provide specific understanding on the impact of attitudinal
factors on end use water consumption behaviour:
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Proposition 2a: Households with higher levels of environmental concern and positive
attitudes towards water conservation will have significantly lower levels of water
consumption across behaviourally influenced end uses (i.e. there is a significant
discretionary component to particular water end use such as showering, irrigation, etc.).
Proposition 2b: There is no significant difference in the consumption of water end uses
which have a lower behavioural influence (e.g. toilet flushing), between households that
have different levels of environmental concern and attitude towards water conservation.
These end uses generally have a fixed and/or low water consumption volume per event.
The following section presents the research method undertaken to test the above detailed
research propositions.
7.4 Research Method
The research forms a component of the Gold Coast Watersaver End Use (GCWSEU) study.
This element of the study integrates and compares end use water consumption data and
attitudinal questionnaire survey data to obtain an understanding of the influence of attitudes on
actual water end use consumption. Two concurrent research activities were carried out being:
(1) water end use data collection and analysis, utilising smart metering technologies and flow
trace analysis software for event disaggregation, respectively; and (2) the development,
application and statistical analysis of an attitudinal and demographic questionnaire survey.
7.4.1 Situational context
Water security is of critical concern in the urbanised South East Queensland (SEQ) region of
Australia. SEQ includes the populations in and between Brisbane, the Gold Coast, Sunshine
Coast and Toowoomba, with the total current population of above 2.8 million people. In the
Gold Coast (population half a million people), residential water consumption accounts for
approximately 75% of the City’s total supply (2008/2009) compared with 57% in nearby
Brisbane City (population 1.8 million people). These high residential water consumption
percentages triggered a focus on residential water users to continually reduce consumption.
Relative to the SEQ water supply situation, the water restriction level and awareness messages
on water are constantly changing hence it is important to set the context during the data
collection period. Leading up to the data collection period, the Gold Coast had been on Level 6
water restrictions which dictate a total outdoor watering ban and encourage residents to
consume 140 L/p/d. Drought breaking rainfalls then occurred, which led to all water restriction
levels being lifted before the data collection period. This relaxation of restrictions was due to the
Hinze Dam, the Gold Coast’s primary water source, being at greater than 95% capacity.
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Leading up to and during the data collection period, frequent messages on saving water in the
home, using 140 L/p/d and rebates programs for installing water efficient devices such as the
‘Home Watersaver’ were in place. End use data was collected from the sampled single detached
households in July 2008. There were no water restrictions in place during the data collection
period. The month of July saw 129.8mm of rain fall, with ten rainfall days above 1mm recorded.
Bulk supplied single detached residential consumption in the Gold Coast for July was 161.9
L/p/d.
7.4.2 Research sample
Data collection was undertaken in four suburban regions within the Gold Coast City. These four
regions were selected based on their apparent differences in socioeconomic classification. The
dates of estate development of all the regions were similar thus ensuring the fixtures and fittings
within homes were relatively comparable.
In total, an initial end use study sample of 151 single detached residential households was
obtained. The extensive research sample was obtained through a multi-staged process of letters
and door knocking. Selection of participants was based on a number of criteria including:
household ownership status (renting/owning) and household makeup (i.e. number of
householders, age of occupants, etc); willingness to be part of the research for a period of two
years; acceptance of multiple water consumption monitoring periods and several surveys with
potential interventions; as well as involvement in a household water appliance stock audit
(Willis et al., 2009b). Historical household volumetric readings for the consenting sample were
also analysed to ensure that the recruited sample’s water use frequency distribution was
representative of the region and City. As a final note, the useable sample for the purposes of this
specific mixed method study was 132, due to the requirement for aligned questionnaire survey
responses, as detailed in a later section.
7.4.3 End use smart metering approach
Standard water meters in the Gold Coast study area were exchanged with Actaris CTS-5 high
resolution water meters. These meters pulse at 72 counts/litre which accounts to a pulse read
every 14mL of water used. DataCell D-CZ21020 data loggers were attached to water meters to
record end use water consumption data (Willis et al., 2010b). Data loggers were set to record
data points in ten (10) second intervals. Data were downloaded from data loggers manually with
laptops via infrared cables. The data were then checked for validity with a two week timeframe
selected for analysis. In home stock inventory surveys, water consumption behaviours and basic
demographic descriptive statistic reports were undertaken to ascertain water devices and usage
behaviours in households. The acquired end use data were analysed with the Trace Wizard™
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software in order to disaggregate flow data into a repository of individual end use water
consumption records for each home. Data analysis involves trained researchers conducting the
end use analysis process of verifying signature traces for each water use activity occurring in the
household, the stock and behavioural surveys aided this process.
7.4.4 Questionnaire development and survey
In addition to monitoring water end use consumption, demographic and attitudinal surveys were
developed and distributed to all the sampled households. The main purpose of the survey was to
solicit respondent ratings for the two attitudinal constructs, namely CE and WC, and to obtain
an understanding on the demographic characteristics of residential water consumers making up
each household. Measurement items contained in the questionnaire evolved from the
abovementioned literature review and factor operationalisation process (Table 7-1 and Table
7-2). A five-point Likert-type measurement scale was adopted for the respondents’ rating of
attitudinal items, with 1 representing strongly disagree and 5 representing strongly agree. Postal
mail was the method for questionnaire distribution. It is important to note that only one
questionnaire survey was completed per household. The head of each household was requested
to convene a meeting with other residents, and consultatively respond to the questionnaire
items, thus providing a response which was representative of the group. In cases where
members could not attend or were young children, they were requested to provide a perceived
rating which reflects their perception of the household’s overall attitude to the listed items. Data
obtained from the survey together with the logged water meter data disaggregated into a
repository of all end use events, were compiled into SPSS version 17.0 for the purpose of
statistical analysis, as presented in the following section.
7.5 Data Analysis and Results
7.5.1 Descriptive statistics
Of the 151 surveys sent, a total of 132 usable responses were received, representing an effective
response rate of 87%. This response rate was high as participants had already consented to being
a part of a two year end use study and had their water meters replaced with those of a higher
resolution and loggers connected. It should be noted that only the water end use data from these
usable 132 survey respondents was used in the subsequent analyses since this was a mixed
method study, whereby both a completed questionnaire survey and water end use data was
required.
The demographic characteristic of survey responses was classified based on household types
and socioeconomic areas. In terms of household types, the majority were made up of small and
Chapter 7: Quantifying the influence of environmental and water conservation attitudes on household consumption
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large families (67%), followed by couples (25%). The remaining 8% was a mix of households
with a single person, share house and family with border. The four research regions included in
the sample were predominately from the middle class range (i.e. lower to upper middle class).
Some socioeconomic descriptive variables have been provided in Table 7-4 to shed light on the
characteristics of the sample.
Table 7-4 Socioeconomic descriptive statistics for sampled regions
Research area
Socioeconomic classification
Total no. of Households
Average property size
(m2)
Average income
Education status
Mudgeeraba Lower Middle to Middle Class
36 646.8 AUD$1387† Mainly High School and Technical
Cassia Park Lower Middle to Middle Class
42 671.7 AUD$1730 Mainly High School and Technical
Crystal Creek Lower Middle to Middle Class
38 655.6 AUD$1606 Mainly Technical and
Tertiary Coomera Waters
Middle to Upper Middle Class
35 806.4 AUD$1987 Mainly Tertiary
151 695.1 AUD$1677 † Note: May 2010 exchange rate was AUD0.821=1USD (i.e. AUD$1387=$1139USD)
Based on the data obtained from the 132 survey respondents, descriptive statistical analysis was
firstly performed on factor measurement items to examine the mean, standard deviation, as well
as the reliability of the measurement scale used in the questionnaire. The results are presented in
Table 7-5. The Cronbach’s Alpha coefficient of 0.91 calculated from the complete set of items
indicates a high level of internal consistency (i.e. reliability) of the scale used in the survey
(Hair et al., 2006).
7.5.2 Measurement model assessment
In addition to assessing the consistency of the scale presented in the preceding section,
Confirmatory Factor Analysis was employed to assess the scale’s construct validity and
unidimensionality. In essence, CFA is a way of testing how well a priori factor structure and its
respective pattern of loadings match the actual data (Hair et al., 2006). CFA can be used to
refine an existing theoretical perspective, support an existing structure, and test a known
dimensional structure in an additional population (DiStefano and Hess, 2005). For the purpose
of this study, CFA was used to confirm the developed factor structure (referred to as
“measurement model”) that represented the set of attitudes toward the environment and water
conservation, respectively, for the study sample (Table 7-1 and Table 7-2). To achieve this,
CFA requires an assessment of model fit, and an indication of how well the hypothesised
measurement model (i.e. the factors and associated indicators presented in Table 7-1 and Table
7-2) represents the data obtained from the survey. This was conducted on the basis of five
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common model fit indices: normal chi-square (2/df); goodness-of-fit index (GFI); comparative-
fit index (CFI); incremental-fit index; and root mean square error of approximation (RMSEA).
To be considered as having an adequate fit, all the indices were measured against the following
criteria: 2/df < 3.00; GFI, CFI, and IFI > 0.90; and RMSEA < 0.08 (Hair et al., 2006).
Table 7-5 Measurement items mean value and standard deviation.
Item code
Item description Mean S.D.
Factor 1: Concern for environment (CE)
CE1 Protection of natural environment for future generations 4.64 0.59
CE2 Community responsibility for reducing water consumption 4.45 0.67
CE3 Concern for environmental problems 4.19 0.73
CE4 Joint responsibility of government and community to ensure water security 4.30 0.69
CE5 Acknowledge water as being a valuable resource 4.52 0.64
CE6 Acknowledge role in creating a sustainable water future 4.24 0.78
CE7 Valuing recycling, composting and other environmentally sustainable activities
4.22 0.72
CE8 Acknowledge humans role as caretaker for environment 4.36 0.64
Factor 2: Water conservation awareness and practice (WC)
WC1 Awareness of opportunities to save water in household 4.41 0.59
WC2 Awareness of the water saving benefits of retrofitting to water efficient fixtures and appliances
4.24 0.73
WC3 Water meter reading competency 3.44 0.88
WC4 Monitoring of water use 3.08 0.92
WC5 Awareness of the relationship between behaviour and water consumption 4.06 0.70
WC6 Water saving knowhow 4.23 0.69
WC7 Perception on efficiency of household water use practices 3.84 0.85
WC8 Seeking continuous savings in water consumption over longer term 4.11 0.75
WC9 Regular reads water meter 3.62 0.76
Note: Cronbach’s alpha (17 items) = 0.91
CFA was conducted using AMOS version 17.0, employing the maximum likelihood estimation
(MLE) method for parameter estimation. The initial results indicated that the measurement
model did not fit the data well. To improve the model fit, a refinement procedure was carried
out, which mainly involved removing items that had insignificant or low factor loading (<0.50),
and low reliability (R2 < 0.50). This procedure led to the elimination of items WC3, WC4 and
WC5. Table 7-6 presents the results of the refined measurement model analysis, showing the
loading, t-value and R2 of each item along with the composite reliability and average variance
Chapter 7: Quantifying the influence of environmental and water conservation attitudes on household consumption
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extracted of each factor. As shown in the table, all of the remaining items have loadings on their
respective factors greater than 0.50, with all t-values being significant at p < 0.001, indicating
convergent validity of the model (Hair et al., 2006). In terms of item reliability, several items
had R2 values lower than the common acceptable level of 0.50, suggesting potential for
elimination. However, since their loadings were meaningful (greater than 0.50) and highly
significant, these items were retained in the measurement model (Koufteros, 1999).
Furthermore, both factors were shown to have a composite reliability well above 0.60, and
average variance extracted being greater than 0.50 (Bagozzi and Yi, 1988). The fit indices of
this model (presented underneath Table 6) also show an acceptable level of fit according to the
criteria mentioned above (2 = 140.59; df = 76; 2/df = 1.85; GFI = 0.86; CFI = 0.93; IFI = 0.94;
RMSEA = 0.08). Therefore, the model was deemed the final measurement model, as illustrated
in Figure 7-1. The figure shows the model’s structure of the factors and their associated items,
correlation between both factors, and the final loadings of all items on their respective construct.
Table 7-6 Measurement model analysis results
Items Loading t-value† R2 Composite Reliability
Average Variance Extracted
Factor 1 (CE) 0.90 0.60 CE1 0.74 f.p. 0.55 CE2 0.81 9.38 0.65 CE3 0.78 9.04 0.61 CE4 0.63 7.14 0.39 CE5 0.63 7.16 0.40 CE6 0.76 8.71 0.57 CE7 0.73 8.39 0.53 CE8 0.74 8.53 0.55 Factor 2 (WC) 0.84 0.55 WC1 0.82 f.p. 0.67 WC2 0.73 9.20 0.53 WC3 Removed WC4 Removed WC5 Removed WC6 0.77 9.82 0.59 WC7 0.56 6.65 0.32 WC8 0.62 7.53 0.39 WC9 0.55 6.42 0.30
Model fit indices: 2 = 140.59; df = 76; 2/df = 1.85; GFI = 0.86; CFI = 0.93; IFI = 0.94; RMSEA = 0.08. f.p., Parameter is fixed for estimation purpose. †All t-values are significant at p < 0.001.
It should be further noted that the high correlation between the two factors (0.95) indicated their
ability to represent aligned concepts (Kline, 2005). However, combining them proved to weaken
the model fit indices. Furthermore, the discriminate validity of the model (i.e. CE and WC
existed as two separate factors rather than one) was supported by the significant Chi-Square
difference statistic between the models with unconstrained and constrained (fixed at 1.00)
correlation coefficients between the two factors (Koufteros, 1999). All of the above results
suggested that this final measurement model (Figure 7-1) possesses adequate convergent
Domestic End Use Investigation: WDM and Dual Reticulation, R.M. Willis (2010)
- 164 -
validity (i.e. all items reliably represented their respective factor), unidimensionality (i.e. all
items only represented their respective factor not the other) and discriminant validity (i.e. two
factors rather than one). The final measurement model’s underlying factor structure was
therefore used in the subsequent analyses.
Concern for Environment
Water Conservation Awareness and
Practice
CE6
CE7
CE8
WC1
WC2
WC6
WC7
0.95
WC8
WC9
0.82
0.73
0.77
0.56
0.62
0.55
CE3
CE4
CE5
CE1
CE20.74
0.81
0.78
0.63
0.63
0.76
0.73
0.74
e1
e2
e3
e4
e5
e6
e7
e8
e9
e10
e11
e12
e13
e14
Concern for Environment
Water Conservation Awareness and
Practice
CE6
CE7
CE8
WC1
WC2
WC6
WC7
0.95
WC8
WC9
0.82
0.73
0.77
0.56
0.62
0.55
CE3
CE4
CE5
CE1
CE20.74
0.81
0.78
0.63
0.63
0.76
0.73
0.74
e1
e2
e3
e4
e5
e6
e7
e8
e9
e10
e11
e12
e13
e14
Figure 7-1 CFA model
7.5.3 Exploration of clusters
Once the factor structure had been refined and confirmed by the CFA, all the retained items
were used as a basis for determining whether there were any distinct groupings evident in the
sample that shared similar patterns of ratings for both the concern for the environment and
water conservation awareness and practice factors. To achieve this objective, cluster analysis
was adopted. According to Hair et al. (2006), cluster analysis is an exploratory data analysis
tool for solving classification problems. Its purpose is to categorise cases into groups or clusters
so that each case is very similar to others in its clusters. Two major stages of the cluster analysis
procedure were carried out in this research: (1) partitioning; and (2) interpretation. The
partitioning stage is the process of determining the number of clusters that may be developed.
The interpretation stage is the process of understanding the characteristics of each cluster and
developing a name or label that appropriately defines its nature (Hair et al., 2006). SPSS version
17.0 for Windows was employed to perform the analysis.
Number of clusters and final centroids
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The hierarchical cluster analysis procedure, incorporating Ward’s method, was conducted on all
fourteen (14) items included in the final measurement model as presented in Figure 7-1. This
clustering procedure involves a combination of the objects into a hierarchy or a treelike
structure, as represented by a dendrogram. A dendrogram provides an indication of
heterogeneity change (average within-cluster distance) for all possible combinations of clusters.
A decision on the final number of clusters is usually based on the combinations that do not yield
a substantial increase in heterogeneity (Hair et al., 2006). From an inspection of the
dendrogram, it was found that a division of two clusters represented the best solution. The final
centroids of the two clusters based on the fourteen items are plotted in Figure 7-2. The cluster
centroids are the mean values for each item that represent the general characteristics of a cluster
(Yeung et al., 2003). Additionally, the results from One-way Analysis of Variance (ANOVA)
showed that the final centroids of both clusters were significantly different across all items.
Figure 7-2 Profiles of clusters’ final centroids
Interpretation of clusters
The characteristics of both uncovered clusters were interpreted through the cluster profiles
presented in Figure 7-2. From the figure, it can be observed that the centroids within Cluster 1
are consistently very high across all items, indicating that this group of respondent had a very
high concern for environment and water conservation. Thus Cluster 1 was labelled VHC. For
Cluster 2, the centroids value for both factors ranged between moderate to high levels,
suggesting that this group of respondents had a moderate to high level of concern for the
environment and water conservation. Hence, Cluster 2 was labelled MHC. To better understand
the characteristics of the clusters, socio-demographic information for the households categorised
within each cluster was subsequently examined with the goal to extract any distinctive features
that could explain the two groups.
2
2.5
3
3.5
4
4.5
5
CE1 CE2 CE3 CE4 CE5 CE6 CE7 CE8 WC1 WC2 WC6 WC7 WC8 WC9
Water conservation awareness and practice (WC)
Cluster 1
Cluster 2
Concern forEnvironment (CE)
Very High
Moderate
Low
Item Centroid
Measurement Item
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Examination of the demographic information for both clusters revealed that the VHC group has
a higher proportion of small and large family households (74%) than that of the MHC cluster
(62%). On the other hand, the percentage of households with couples in the VHC group (21%)
was lower than that of the MHC group (27%). The average household lot sizes for the two
clusters were very similar, being 683m2 and 691m2, for MHC and VHC, respectively. The VHC
cluster had a lower average income (AUD$1584; USD$1300 May 2010) than the MHC cluster
(AUD$1744; USD$1431). Whilst, this difference is not statistically significant due to the
relatively small sample size (F=1.370; p=0.244), it could provide some indication that
environmental and water conservation concern may become less important to greater
proportions of people in the upper middle and higher classes. An attempt to shed some light on
the influence of socioeconomic factors on the relationship between attitudes and water
consumption behaviours is provided later.
7.5.4 Water consumption end use analysis
Overall end use consumption
The breakdown of end use water consumption for the total sampled households in the Gold
Coast (n=132) is presented in Figure 7-3. The overall average consumption for the sampled
Gold Coast households (n=132) was 152.3 L/p/d. It should be noted, that while attitude ratings
and water end use comparisons are made at the household entity level, total water consumption
and end use break downs are necessarily presented as L/p/d in order to level consumption
volumes considering household size.
Figure 7-3 Average daily per capita consumption per end use: total sample (n=132)
The highest end use is showering, with each person consuming just over 47 litres of water per
day or 31% of total use. The next highest end use is clothes washing accounting for 20% of total
Shower47.1 L/p/d
31%
Clothes Washer30.0 L/p/d
20%
Tap26.6 L/p/d
17%
Dishwasher
2.2 L/p/d1%
Bathtub5.5 L/p/d
4%
Toilet20.9 L/p/d
14%
Irrigation18.0 L/p/d
12%
Leak
1.8 L/p/d1%
Total = 152.3 L/p/d
Chapter 7: Quantifying the influence of environmental and water conservation attitudes on household consumption
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consumption or 30 L/p/d. Tap use, toilet flushing and irrigation follow with end use percentages
of 17%, 14% and 12%, respectively. Bath use, dishwashing and leaks make up a small
component of water end use with percentages ranging from 1% to 4%. Figure 7-4 demonstrates
the end use water consumption breakdown for each of the measured 132 households.
0.0
50.0
100.0
150.0
200.0
250.0
300.0
350.0
400.0
140
100
167
173
199
45
191
56
51
41
200
23
185
163
103
111
74
192
36
152
106
75
124
127
33
50
130
115 1 69
89
67
24
68
150 4 94
144
79
114
110
176
82
88
120
85
170
93
156
71
81
177
149
131
46
62
105
136
178
165
73
20
13
143
80
10
Per Capita Con
sumption (L/p/d)
Household ID
Leak
Irrigation
Toilet
Bathtub
Dishwasher
Tap
Clothes Washer
Shower
Figure 7-4 Household daily per capita consumption distribution with water end use breakdown: total sample (n=132)
Clustered water consumption end use
Two attitudinal clusters for the sampled households, namely VHC and MHC, were determined
earlier based on the household residential perceptions regarding their concern for environment
and water conservation awareness and practice. The VHC cluster denotes the group of
households with a very high level of concern, whereas the MHC cluster represents the group
with a moderate level of concern for the environment and water conservation awareness and
practice. Further examination and comparison of the end use consumption levels, between the
two clusters, could thus provide a basis for understanding the relationship between the herein
measured environmental and water conservation attitudinal levels of concern and the actual end
usage of water. To achieve this, the flow trace analysed average daily per capita end use
consumption (i.e. L/p/d) for each household associated with the two extracted clusters (i.e. VHC
and MHC) was assigned and compared.
Figure 7-5 shows the breakdown of average daily per capita consumption (L/p/d) of the
households in the VHC cluster (n=54). The VHC average total water use was 128.2 L/p/d,
which is less than that for the combined 132 household sample (152.3 L/p/d). When considering
individual end use activities, it was found that the volumetric consumption for all categories was
lower than that of the total sample, with the exception of dishwasher. It can be further observed
that the proportion of average daily per capita consumption (i.e. percentage) of most end use
categories between the VHC cluster and the total sample is similar. However, of note is the
proportion of irrigation use for the VHC cluster (8%), which is considerably less than that of the
total sample (12%); as discussed the lot sizes of the two clusters is not significantly different.
Max = 375.6 L/p/d
Average = 152.3 L/p/dMin = 38.4 L/p/d
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Figure 7-6, presents the VHC clusters’ descending profile for each individual households’ water
end use consumption breakdown, indicating that the majority of households in this sub-sample
consumed water less than 150 L/p/d. Two excessively high users are present, whose average
consumption was in the order of 350 L/p/d. These two outliers potentially represent households
whose reported attitudes do not adequately reflect their actual behaviours.
Figure 7-5 Average daily per capita consumption: VHC cluster (n=54)
0.0
50.0
100.0
150.0
200.0
250.0
300.0
350.0
400.0
140
167
45
56
116
103
15
75
53
60
64
181
54
69
67
24
171
68 4
30
70
114
134
176
25
198
11 2
170
93
107
156
42
71
95
177
57
83
133
46
49
166
14
136
178
154
190
73
55
20
13
145
80 3
Per Capita Consumption (L/p/d)
Household ID
Leak
Irrigation
Toilet
Bathtub
Dishwasher
Tap
Clothes Washer
Shower
Figure 7-6 Household daily per capita consumption distribution profile: VHC cluster (n=54)
The break down of average daily per capita consumption (L/p/d) for the households in the MHC
cluster (n=78) is presented in Figure 7-7. It can be observed that the proportion of all the
average end use categories of this cluster is similar to that of the total sample presented in Table
7-3. For this cluster, the average total water use was 169.0 L/p/d, being higher than that of the
total 132 sample consumption (152.3 L/p/d). Similarly, the end use consumption for all
categories, except dishwasher, is also higher than that of the total sample. Figure 7-8 presents
the MHC clusters’ descending profile for each individual households’ water end use
Shower41.5 L/p/d
32%
Clothes Washer25.0 L/p/d
20%
Tap
22.9 L/p/d18%
Dishwasher2.3 L/p/d
2%
Bathtub
4.5 L/p/d4%
Toilet19.9 L/p/d
15%
Irrigation
10.8 L/p/d8%
Leak
1.3 L/p/d1% Total = 128.2 L/p/d
Max = 375.6 L/p/d
Average = 128.2 L/p/d
Min = 38.4 L/p/d
Chapter 7: Quantifying the influence of environmental and water conservation attitudes on household consumption
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consumption break down. It can be seen that more than half of the households in this sub-
sample consumed more than 150 L/p/d.
Figure 7-7 Average daily per capita consumption: MHC cluster (n=78)
0.0
50.0
100.0
150.0
200.0
250.0
300.0
350.0
400.0
19
100
28
101
173
148
199
119
132
191
72
161
51
187
41
77
200
40
23
43
185
163
52
196
111 8
74
160
192
39
36
122
152
106
32
124
129
127
17
33
50
158
130
115 1
162
89
35
155
65
150
66
94
84
144
79
92
175
110
82
88
108
120
85
141
81
47
149
131
62
105
180
165
29
143
86
139
10
Per Capita Consumption (L/p/d)
Household ID
Leak
Irrigation
Toilet
Bathtub
Dishwasher
Tap
Clothes Washer
Shower
Figure 7-8 Household daily per capita consumption distribution profile: MHC cluster (n=78)
Clustered comparative analysis
Results from the preceding section provided illustrative evidence that end use water
consumption varies depending on the environmental attitudes of consumers. Further
investigation was undertaken to determine the level of statistical difference for each end use
category. To achieve this, an independent sample t-test was carried out using the two extracted
clusters as input samples. The results from this test, as presented in Table 7-7, show that total
water consumption volumes for these two clusters are statistically different, with the VHC
cluster having 24.1% lower consumption (128.2 L/p/d) than that of the MHC (169.0 L/p/d).
Furthermore, consumption levels for the four defined discretionary end use categories (i.e.
shower, clothes washer, tap and irrigation) are all significant at 0.05 level, suggesting that there
Shower51.0 L/p/d
30%
Clothes Washer33.5 L/p/d
20%Tap
29.2 L/p/d17%
Dishwasher
2.1 L/p/d1%
Bathtub6.2 L/p/d
4%
Toilet
21.7 L/p/d13%
Irrigation
23.0 L/p/d14%
Leak
2.2 L/p/d1%
Total = 169.0 L/p/d
Max = 355.4 L/p/d
Average = 169.0 L/p/d
Min = 41.4 L/p/d
Domestic End Use Investigation: WDM and Dual Reticulation, R.M. Willis (2010)
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is a relationship between the households’ levels of water conservation and environmental
concern, and actual water end use consumption. Irrigation represents the most significant
difference, where the VHC cluster (i.e. 10.8 L/p/d) has a 12.2 L/p/d or 53.0% reduction from the
MHC cluster (i.e. 23.0L/p/d). Expectedly, Table 7-7 also shows that the two non-discretionary
end uses such as dishwasher and toilet, which are largely not affected by household behaviours
due to their mechanical nature, were not significantly different. A discussion on total,
behaviourally influenced water consumption end use differences, along with an exploratory
analysis on the socio-demographic factors underpinning these differences, is outlined below.
Table 7-7 Clustered comparative analysis results.
Average daily per capita water consumption (L/p/d)
Cluster comparison statistics (MHC versus VHC)
End use category
Overall (n=132)
MHC (n=78)
VHC (n=54)
Difference (L/p/d)
Difference(%)†
p-value
Significant at 0.05
level (Y/N)?
Discretionary Shower 47.1 51.0 41.5 9.5 18.6% 0.043 Y Clothes Washer
30.1 33.6 25.0 8.6 25.6% 0.031 Y
Tap 26.6 29.2 22.9 6.3 21.6% 0.002 Y Irrigation 18.0 23.0 10.8 12.2 53.0% 0.049 Y Non-discretionary
Dishwasher 2.2 2.1 2.3 0.2 -9.5% 0.609 N Bathtub 5.5 6.2 4.5 1.7 27.4% 0.314 N Toilet 20.9 21.7 19.9 1.8 8.3% 0.333 N Leak 1.8 2.2 1.4 0.8 36.4% 0.105 N Total consumption
152.2 169.0 128.3 40.7 24.1% 0.001 Y
†Relative to average daily per capita consumption of the MHC group (positive percentage represents a reduction in consumption)
7.6 Discussion
7.6.1 Overview on water consumption and attitudes
Cluster analysis results indicated that survey respondents could be classified into two
environmental attitudinal groups, namely VHC and MHC. Residents clustered in the VHC
group reported very high levels of understanding and concern for the environment and water
conservation, whereas those in the MHC cluster reported only a moderate level. Total water
consumption, as well as the disaggregated water end uses categories that sum to this total, were
aligned with household attitudinal ratings and compared. Three propositions were established
and the calculated statistical results support the view that water end use consumption levels can
significantly differ depending on the resident’s level of concern toward the environment and
water conservation. Both the VHC and MHC groups displayed differing end use water
consumption levels and possessed divergent characteristics. The following sections provide
Chapter 7: Quantifying the influence of environmental and water conservation attitudes on household consumption
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further discussion, which outlines the supportive evidence for the listed propositions as well as
proposes some of the underlying factors contributing to the current situational context.
Relationship between attitudes and total water consumption
It was hypothesised in this research that households with higher levels of environmental concern
and attitude towards water conservation will consume significantly less water in total. The
analysis results provided empirical evidence which supports the first proposition (Proposition 1)
by demonstrating that the VHC cluster households consumed significantly less water than the
MHC cluster households. This finding provides further support to previously reported research
studies (Nancarrow et al., 1996) by revealing the link between positive attitudes and
commitment towards the environment and water conservation. These supportive attitudes often
result in improved water conservation behaviours which, in turn, lead to lower levels of total
water consumption in households.
Relationship between attitudes and discretionary end use consumption
The smart metering approach employed enabled the monitoring of water end use events. Of
these end uses, five were considered to be strongly influenced by behavioural aspects: shower,
clothes washer, tap, bathtub and irrigation. Results from the clustered comparative analysis
indicated significant differences in water consumption in all behaviourally influenced end uses,
with the exception of bathtub, demonstrating that VHC residents consumed significantly less
water in these end uses than the MHC residents. This finding provides empirical support for
Proposition 2a, demonstrating that households with higher levels of environmental concern and
positive attitude towards water conservation have significantly lower levels of consumption in
behaviourally influenced water end uses. It should be noted that the reason water use in bathing,
despite being considered moderately influenced by behaviours, showed no significance
difference between the two clusters could be due to the fact that only a few households in the
sample undertook this activity, thus making statistical comparisons less reliable.
Importantly, the above findings imply that there is a positive relationship between attitudes
towards the environment and water conservation and water end use consumption across
behaviourally influenced end uses. As discretionary end use consumption varies entirely based
on the decision of water users to consume beyond what is necessary, those water users with
positive attitudes towards environmental sustainability would tend to be more cautious when
using water than those who do not highly value or consider the environment. Examples of
sustainable activities potentially undertaken by the VHC residents could include: (1) showering
over smaller durations with high efficiency showerheads; (2) washing clothes in water efficient
washing machines and residents waiting until they have a full load before commencing
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washing; (3) only watering outdoors when absolutely necessary; (4) not continuously running
taps for rinsing dishes; and (5) turning off taps when brushing teeth or washing vegetables.
The potential water savings achievable across certain end uses, through transforming
households’ attitudes, is highly evident (Table 7-7). Improving the attitudes of MHC residents
could mean the reduction in water consumption across discretionary end uses, ranging from
approximately 18.6% to 53.0%. Such savings, when translated across entire cities, would ensure
greater urban water security in a time where climate variability is becoming more prevalent.
This benefit, however, needs to be further examined in future research through a longitudinal
study implementing and monitoring the influence of education programs to improve the
attitudes of water users.
Relationship between attitudes and non-discretionary end use consumption
Because non-discretionary end uses are those water use activities that tend to be consumed to
satisfy basic need or function without being much affected by the users’ behaviour, it was
hypothesised in this research that there will be no significant differences in non-discretionary
water end uses between households having different attitudes towards the environment and
water conservation (Proposition 2b). The two end use events that considered as non-
discretionary are toilet and dishwasher. As anticipated, these end uses did not have any
significant difference across the VHC and MHC clusters, thus providing empirical support for
this proposition. This finding demonstrates that differences in attitudes towards the environment
and water conservation are not associated with the consumption of non-discretionary water end
uses.
Leakage was not classified as either a discretionary or non-discretionary end use. It is
worthwhile noting that the levels of leakage did not differ between the two clusters. Some
visible components of leakage such as rectifying continuously running cisterns are affected by
behaviours, but less visible leakage was not considered to be affected by behaviours. Due to the
small number of households with significant leakage, and the resulting low volumes within each
cluster, it is difficult to reliably assess this relationship in the present study. Nonetheless, some
of the urban water researchers associated with this study is examining such an issue in a
separate investigation (Britton et al., 2008; Britton et al., 2009).
7.6.2 Linking socio-demographic variables with attitudes
In addition to examining the relationship between attitudes and water consumption, the
interpretation of clusters revealed some demographic characteristics that had higher
representation in each identified cluster. The VHC residents consisted of a larger proportion of
families whereas the MHC cluster had a lower proportion of families and higher proportion of
Chapter 7: Quantifying the influence of environmental and water conservation attitudes on household consumption
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singles and couples. This suggests that families may have higher awareness or understanding of
the environment and water conservation practices and higher application of such knowledge.
The study indicated that there was no difference between the average lot sizes of the two
clusters, indicating that irrigable area was not a contributing factor to the difference in irrigation
end use volumes. As discussed previously there was a difference between the average incomes
for the two clusters, albeit not statistically significant. Nonetheless, this difference does provide
some persuasion for future research to explore whether households that have higher disposable
incomes (i.e. upper middle and high classes) are more likely to have less regard for resource
conservation, particularly low cost resources such as potable water.
Other studies have indicated that affluence may play a significant part in higher water
consumption behaviours (CSIRO, 2002; Kim et al., 2007; Kenney et al., 2008). In summary,
whilst the authors acknowledge that a wide range of other contributing factors, beyond
environmental/water attitudes such as pricing or demographics, contribute to water consumption
behaviours, the study provides strong indications that attitudes play a predominant role in water
conservation. Further research on attitudes towards environment and water conservation across
different socio-economic groups could provide additional insight into domestic water
consumption behaviour and would assist in triggering the development of targeted awareness
messages.
7.7 Conclusions and Implications
This paper presented findings from a component of the GCWSEU. The herein discussed
component of the greater research program was focused on establishing if attitudes influence a
range of end use water consumption levels; such a mixed method study has not been reported in
the literature. The research findings provided empirical support to the propositions that pro-
environmental and water conservation attitudes result in household total water savings, and
across the majority of discretionary end uses, respectively.
Two attitudinal constructs, concern for the environment and water conservation awareness and
practice, were statistically validated following a measurement reliability and scale analysis
process. Subsequently, cluster analysis uncovered two distinct groups of households, being
those with very high concern (VHC) and those with moderate to high (MHC) concern. Smart
meters were utilised to collect high resolution (0.014 L/pulse) flow data, which was then
disaggregated into end uses for the 132 households involved in the study. Three research
propositions were developed and tested. Overall, it was established that strong positive
environmental and water conservation attitudes resulted in significantly (p < 0.05) lower total
water consumption as well as for the behaviourally influenced end use categories (i.e. shower,
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clothes washing, irrigation and tap use). Bath use was not affected by attitudes potentially due to
the small number of household residents partaking in this activity. Non-discretionary toilet and
dishwasher use was not influenced by attitudes as predicted. Leakage being categorised as
neither a discretionary or non-discretionary use was also not shown to be impacted by attitudes;
however, examining this end use category was outside the scope of this research. Residents with
a high level of concern or attitude towards the environment had a higher representation of
families than couples and slightly higher incomes, although this was not at a significant level.
The results from this research provide water demand management professionals with an
understanding on where educational programs should be targeted to obtain the highest effective
household water savings. Significant water savings in high end uses within homes can be
achieved if pro-environmental attitudes can be effectively instilled. This research supports the
development of directed awareness information focused on improving the current level of
understanding of sustainable shower, clothes washing, irrigation and tap use behaviours. Such
targeted programs will result in significant reductions in water consumption within residential
households. The study provides empirical evidence to support the view that if society at large
values water and is actively concerned with how it is being consumed, significant reductions in
consumption levels can occur. This in turn will lead to a reduced requirement for
environmentally adverse water supply alternatives (e.g. desalination plants) to support demand.
As a final note, the findings and herein described research methods could also be applied to
investigate relationships between attitudes and resources (i.e. water, energy and materials) and
conservation in the commercial and industrial sectors.
7.8 Acknowledgements
The research forms a component of the Gold Coast Watersaver End Use (GCWSEU) study, a
research collaborative between Griffith University and Gold Coast Water under an Australia
Research Council (ARC) grant. Gold Coast Water is acknowledged for their financial and in-
kind support to the herein described study. The Institute for Sustainable Futures, Wide Bay
Water Corporation and the Queensland Water Directorate are also acknowledged for their
involvement in the research collaborative. Lastly, the authors appreciate the invaluable
comments from the anonymous reviewers of an earlier version of this paper
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Chapter 8
Alarming visual display monitors affecting shower end use water and energy
conservation in Australian residential households
This chapter is a reformatted version of a peer-reviewed article by the author published in the
Journal of Resources, Conservation and Recycling, Vol 54:12, pp. 1117-1127, DOI:
10.1016/j.resconrec.2010.03.004.
8.1 Abstract
Sustainable urban water consumption has become a critical issue in Australian built
environments due to the country’s dry climate and increasingly variable rainfall. Residential
households have the potential to conserve water, especially across discretionary end uses such
as showering. The advent of high resolution smart meters and data loggers allows for the
disaggregation of water flow recordings into a registry of water end use events (e.g. showers,
washing machine, taps, etc.). This study firstly reports on a water consumption end use study
sample of 151 households conducted in the Gold Coast, Australia, with a focus on daily per
capita shower end use distributions. A sub-sample of 44 households within the greater sample
was recruited for the installation of an alarming visual display monitor locked at 40 litres
consumption for bathroom showers. All sub-sample shower end use event durations, volumes
and flow rates were then analysed and compared utilising independent sample t-tests pre- and
post intervention. The installation of the shower monitor instigated a statistically significant
mean reduction of 15.40 litres (27%) in shower event volumes. Monetary savings resulting from
modelled water and energy conservation resulted in a 1.65 year payback period for the device.
Furthermore, conservative modelling indicated that the citywide implementation of the device
could yield 3% and 2.4% savings in total water and energy consumption, respectively.
Moreover, a range of non-monetary benefits were indentified, including the deferment of water
and energy supply infrastructure, reduced resource inflationary pressures, and climate change
mitigation, to name a few. Resource consumption awareness devices like the one evaluated in
this study assist resource consumers to take ownership of their usage and individually tackle
individualistic and/or society driven conservation goals, ultimately helping to reduce the
ecological footprint of built environments.
Chapter 8: Alarming visual display monitors affecting shower end use water and energy conservation
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8.2 Background
8.2.1 Climate change and improving urban water security
In many parts of the world, an escalating demand on potable water resources resulting from
increasing populations has become commonplace (Willis et al., 2009a). While this has triggered
higher water consumption, water availability is also becoming increasingly variable due to the
global change of climate (Inman and Jeffrey, 2006). In Australia, a recent drought period
between 2001 and 2004 touched most of the continent and demonstrated the severe localised
impacts of climate change. Moreover, after almost five years of continued lower-than-average
rainfall across most of the eastern part of the Australian continent, many Australian cities and
towns continue to face drought conditions with some water supply reservoirs at their lowest
recorded levels.
A recent report by the Australian National Climate Centre showed trend annual rainfall
decreasing by up to 50mm per year over the southern half of the continent (CSIRO, 2007).
Coupled with such water scarcity is increasing urbanisation, which intensifies the concern over
the existing urban water resources and places a strain on future water security. A study by
Birrell et al. (2005) on the impact of demographic change and urban consolidation on domestic
water use in Australian cities revealed that, during 2001-2031, water demand in major cities will
increase by an average of 37%. Such evidence of dwindling supplies and increasing demand has
triggered water industries and all levels of government to seriously reconsider the management
of water resources in Australia. Hence, a significant investment in adequate planning and the
adoption of smarter approaches to water management is required to ensure a sustainable water
future.
From a worldwide perceptive, many governments and public utilities who are similarly affected
by water crises, are investing significant funds in the development and implementation of water
strategies to ensure future water demands can be met. Predictions and estimations of future
demand and potential savings through the introduction of demand management strategies or
source substitution options are now commonplace. Demand management strategies include
water metering, water restrictions, rebate programs for water efficient devices, water efficiency
labelling, water conservation or education programs and pressure and leakage management
(Inman and Jeffrey, 2006). Source substitution or ‘fit for use’ water involves replacing specific
potable end uses such as toilet flushing and irrigation with recycled, grey or storm water. Water
savings achievable from such programs are calculated through a variety of assumptions but,
once in place, limited consideration is given to determining the actual water savings associated
with these strategies. It is well documented that more data and information should be collated on
the effectiveness and sustainability of demand management techniques, to improve long term
Domestic End Use Investigation: WDM and Dual Reticulation, R.M. Willis (2010)
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forecasting (Chambers et al., 2005). After decades of inadequate metering of water use,
organisations have come to the realisation that it is impossible to manage water resources
without having adequate measuring and monitoring practices (Hearn, 1998).
8.2.2 Domestic water consumption and conservation
Residential water consumption can account for up to 66% of the total supplied water as was the
case at the Gold Coast, Australia in the 2007-2008 monitoring period. Residential water
consumption has previously been determined to be effected by seasonal changes and water
demand management (WDM) strategies such as water metering, water restriction levels, water
efficient devices and education (Nieswaidomy, 1992; Mayer et al., 2004; Inman and Jeffrey,
2006). Although prior research has occurred, it is well established that there is a need for
specific country and location based research as different community attitudes and behaviours
can influence the effectiveness of WDM strategies (Corral-Verdugo et al., 2002; Turner et al.,
2005). To grasp the effectiveness of WDM strategies high quality data is required, hence the
development of smart metering techniques.
8.2.3 Advent of smart water metering and end use analysis
The need for smart water metering stemmed from the fact that traditional systems do not
provide real-time water consumption data or sufficient data points to determine usage patterns.
Conventional water meters count litres of water as it passes through the meter without the
ability to record when (i.e. time of day) and where the consumption takes place (e.g. clothes
washing, leakage, shower use, etc.). Water consumption readings are generally recorded
manually on a quarterly or half yearly basis. Under most situations, a whole year’s worth of
water consumption data is described by only two to four data points (Britton et al., 2008). No
further information is available to draw upon should there be any queries (Hauber-Davis and
Idris, 2006). Obviously, this conventional water metering system produces limited, delayed
water consumption information and is unable to provide effective support for water planning
and management processes. Moreover, it is not adequate to meet the increasing level of
government scrutiny on the utilisation of water resources or the effectiveness of WDM
strategies and does not assist society at large to address the pressing water security issues
associated with climate change.
The concept of smart metering embraces two distinct elements: (1) meters that use new
technology to capture water use information; and (2) communication systems that can capture
and transmit water use information as it happens, or almost as it happens. Smart water meters
essentially perform three functions; they automatically and electronically capture, collect and
communicate up-to-date water usage readings on a real-time basis (Idris, 2006). To achieve this
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objective, the reed switch on traditional volumetric water meters is modified to collect a high
resolution record of water use (i.e. from the traditional 2 to 72 pulses per litre or 0.014 litres per
pulse) which can then be disaggregated into individual water use events using a flow trace
analysis software tool (e.g. Trace Wizard©). The high resolution water measurement
information from the meter is then captured by attached high data capacity loggers (i.e. 2
million readings) recording information at a pre-set time interval (e.g. 5 seconds). Time scaled
flow recording information is then collected in-situ through infrared cables or wirelessly
through a mobile phone network. Once a representative sample of data is collected, the flow
trace analysis software tool is applied to disaggregate flow traces into a list of component events
assigned to a specific end use appliance or fixture (e.g. shower, toilet, clothes washing, etc.).
Stock and behaviour surveys can also be utilised to help the analyst develop templates which
encapsulate the appliance properties of end use events and ensure accurate end use
categorisation. Once analysis has been completed a database registry of all end use events
occurring during the sampled period is established and can subsequently be utilised for water
planning and management research as demonstrated herein.
Hence, a smart meter is a high resolution water meter (e.g. 72 pulses per litre) linked to a device
(a data logger) that allows for the continuous reading of water consumption. Smart metering
allows for communication of captured data to a broad audience, e.g. utility managers,
consumers and facility authorities. Smart metering is an established technology which is now
cost-effective enough to be applied to collect, store and distribute real-time water consumption
data (Hauber-Davis and Idris, 2006). An automated meter reading system with this capability
provides benefits for both consumers and water authorities for monitoring and controlling water
consumption. Understanding and collecting empirical evidence of where and how water is used,
through smart metering, allows planners and conservationists to determine the relative water
saving of WDM strategies.
8.2.4 Engineered water conservation appliances and fixtures
The development of water efficient devices such as low flow shower roses or dual flush toilets
has led to effective water savings within households. Several studies have been undertaken to
determine the relative water savings attributed to the installation of engineering water
conservation fixtures and appliances. The replacement of high water consuming devices with
those of engineered water efficiency has resulted in indoor water consumption savings between
35 - 50% (Mayer et al., 2004; Inman and Jeffrey, 2006).
A variety of water saving devices are available on today’s market which attempt to reduce water
end use consumption. Such devices include toilet dams, AAA rated shower roses, dual flush
toilets (3/4.5 L/flush), water pressure limiting devices, and tap aerators, to name a few. With
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respect to showers, the trend of lower shower consumption volumes with more efficient devices
has previously been established by Mayer et al. (2004). In more recent times, the development
of visual display technologies and alarming devices designed to influence both water and energy
conservation responses at the end use level have become more readily available. Therefore, in
addition to retrofitting appliances and fixtures with those of a higher efficiency, such display
technologies provide a dynamic feedback to resource consumers, ultimately influencing
behaviours.
8.2.5 Visual display technologies and alarming devices influencing resource
conservation behaviour
While houses with water saving devices typically demonstrate reduced end use water
consumption, evidence also which indicates that engineered savings can often be diminished by
human behaviour. For instance, a study by Inman and Jeffrey (2006) resulted in an increase in
water consumption after the installation of water saving devices. This was due to the resident’s
misguided belief that they were saving water through their efficient devices and hence took
longer showers which often resulted in higher consumption volumes. The “Human Exception
Paradigm” is a basic belief that humans are above nature and therefore do not have to regard it
as they consume resources (Bechtel et al., 1999). Thus, these primitive beliefs can serve to
inhibit conservational behaviour. A study into the link between environmental behaviour and
water conservation behaviour determined that general environmental beliefs affected the
specific beliefs regarding the use of water, which in turn, correlated with the measure of water
consumption (Corral-Verdugo et al., 2003). Waisbord (1999, p. 2) states that ‘interventions are
needed to provide people with information to change behaviour’ and that it is a lack of
knowledge which contributes to problems in development. Education is a key component for
changing behaviour and attitudes towards water use (Webb, 2007). If people are made aware of
their water usage, more importantly their water wastage, they are much more likely to actively
reduce their consumption.
Essentially, the use of electronic visual and/or alarming monitoring devices provides immediate
feedback to resource users. Compared with written feedback such as quarterly bills, electronic
devices provide quicker and more frequent feedback, thus better informing the consumer of the
consequence of their specific behaviours (Midden et al., 2007; Darby, 2006). It is especially
effective when information is given frequently which is the case with continuous electronic
feedback (Abrahamse et al., 2007). In general, feedback enables people to be more conscious of
the relevance and affect of their own behaviour. When resource consumption is closely linked to
specific appliances and activities, the relevance and direct affect of behaviour becomes clearer.
Through appliance-specific feedback, the consumer can determine how a certain appliance or a
particular way of using it affects the amount of water or energy resource consumed. This allows
Chapter 8: Alarming visual display monitors affecting shower end use water and energy conservation
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the consumer to curb poor behaviours and to use resource consuming appliances more
effectively to achieve higher savings and shift towards sustainable consumption habits (Fisher,
2008).
In the electricity sector, immediate feedback through electronic devices has been regarded to be
very effective in helping to conserve energy (Wood and Newborough, 2003; Fischer, 2008).
Specifically, electronic visual displays have proven to be useful in promoting energy
conservation behaviour in people, based on extensive research conducted worldwide. In the US,
McClelland and Cook (1979-1980) carried out a study using the Fitch Energy Monitor (FEM)
that displays the total electricity usage and reported a 12% reduction in electricity usage in
households with the FEM compared with those without it. Similarly, in Canada, Dobson and
Griffin (1992) investigated the use of the Residential Electricity Cost Speedometer (RECS)
system, which measured household electricity consumption and presented cost and electricity
consumption for various end uses displayed on an hourly, daily, monthly and annual basis. The
results showed that the use of the RECS system helped reduce the average daily energy
consumption by 12.9%. The above findings appear to be consistent with those found in Japan by
Ueno et al. (2005, 2006), who conducted a series of experiments on the use of a computerised
interactive “energy consumption information system” that displays daily energy consumption
for all the domestic appliances within a household. They found that the use of such a tool led to
9-12% reduction in power consumption, and that energy-conservation awareness affected not
only the power consumption of the appliances explicitly shown on the display monitor, but also
other household appliances implying a change in consumption behaviours. In the UK, Wood
and Newborough (2003) compared the effectiveness of providing paper-based energy-
use/saving information with electronic feedback of energy-consumption via smart meters and
energy consumption indicator (ECI) displays. The findings showed that the average reduction
for households employing an ECI was 15%, whereas those that were only given paper-based
energy saving information reduced their electricity consumption, on average, by only 3%.
In the water sector, research on the impact of visual displays and alarming devices on water
conservation is still limited. In the US, Arroyo et al. (2005) developed a device called
“WaterBot” that presents immediate feedback in the form of visual and auditory reminders. The
device is to be installed on household faucets to motivate people to turn off the tap when the
water is not being used. Although there has been no systematic experiment conducted to
quantify the water savings from installing the device, pilot studies through observations and user
reports suggested a behavioural change that could reduce water consumption by the presence of
the device. Recently, Kappel and Grechenig (2009) developed a shower water meter (show-me)
that displays the amount of water used during one shower in the form of LEDs assembled on a
stick, and installed the device in several households in Austria. The results showed a decrease in
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the mean shower water consumption of approximately 10 litres. This suggested a promising
water saving potential in the shower with regards to using visual displays for delivering
feedback.
In the case of this study, the WaiTEK® Shower Monitor© is an innovative device that provides
the alarming visual feedback intervention (Figure 8-1). This educational engineering device
provides a digital read-out of shower parameters such as flow rate, duration and temperature.
While most water saving devices physically limit the volume or flow rate of water that can be
used, this monitor does not affect the shower in any way. Rather, it simply provides the
information necessary to allow households to shower more efficiently. At the end of the
predetermined shower duration, it will beep for duration of one minute to indicate that it is time
to get out of the shower. This device aims at educating the public on their shower water
consumption as it is essential to encourage and develop behaviour leading towards sustainable
water consumption. Therefore the effectiveness of the monitor far supersedes any other water
saving device on the market as it addresses the underlying issue of first changing the beliefs and
behaviours of the shower users, rather than simply enforcing a restriction. Armed with this
information, shower users can supervise their own habits to ensure they adequately conserve
water.
Figure 8-1 Alarming visual display device
8.2.6 Overview of Gold Coast Watersaver End Use study
Currently, there are no end use water consumption models for the urban South-east Queensland
(SEQ) region of Australia. This region has a sub-tropical climate and has recently experienced
severe drought conditions, forcing both State and Local Governments to develop numerous
strategies to reduce water usage. In this respect, gaining empirical evidence of how and where
water is used and determining the effectiveness of specific WDM strategies is critical for
planners, utilities and conservation professionals. This information can be used to improve the
design of conservation programs and can provide justification for continued support of
conservation efforts (Mayer and DeOreo, 1999). As mentioned, per capita consumption varies
Chapter 8: Alarming visual display monitors affecting shower end use water and energy conservation
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significantly throughout regions within the world, hence the need for location and country based
research is necessary to determine the effectiveness of WDM (Turner et al., 2005; Inman and
Jeffrey, 2006). In addition, it has been acknowledged that community attitudes and behaviours
can also influence the effectiveness of water savings resulting from WDM strategies (Corral-
Verdugo et al., 2002). In the US, Mayer and DeOreo (1999) have explored some relationships
between water consumption and demographic variables at the end use level. Their research
suggested that demographic variables such as family size and age distribution, wealth or
income, ownership status and household attitudes towards using and conserving water,
influence household water consumption (Mayer and DeOreo, 1999; Taverner Research, 2005;
Turner et al., 2005; Kenney et al., 2008). However, in Australia, there has been minimal
research on investigating end use water consumption with relation to demographic variables
within monitored homes.
Motivated by the above research demand, Griffith University and Gold Coast Water have
collaborated under an Australian Research Council (ARC) grant to conduct an investigation of
end use water consumption in the Gold Coast region. This investigation is aptly named the Gold
Coast Watersaver End Use (GCWSEU) study. Other primary objectives of the research are to
examine the effectiveness of dual reticulation and education as potable water saving
mechanisms. Dual reticulation is a water supply system which consists of two separate main
supplies to the consumer: one drinking or potable water; and the other non-drinking or recycled
water (Water Services Association of Australia (WSAA), 2002). The research also aims to
establish a dataset which compiles end use water consumption data, demographic information,
and attitudinal data. As stated by Kenney et al. (2008), the collection and integration of these
datasets, especially household level consumption data with demographic data about the people
and house, rarely occurs. The utilisation of these datasets allows for the investigation of the
effect of demographic variables, attitudes and behaviours on water consumption.
This paper reports findings from the pre-intervention phase of the study, which included the
winter 2008 end use data for 151 households along with the water end use for shower events
post implementation of the WaiTEK® Shower Monitor© (Figure 8-1). Study objectives and the
scope of the herein focused study are presented below.
8.3 Research Objectives
WDM and 'fit for purpose' water consumption has changed the current focus to demand, rather
than supply side measures, to meet the ever increasing requirement on diminishing water
resources. WDM strategies such as water metering, water restrictions, rebate programs for water
efficient devices, water efficiency labelling, water conservation education programs, and the
Domestic End Use Investigation: WDM and Dual Reticulation, R.M. Willis (2010)
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application of recycled, grey and stormwater for specified end uses have been introduced
throughout Australia and the world. However, water authorities still have vague indications on
the effectiveness of these programs. This paper provides an in-depth investigation into an
alarming visual display device, namely the WaiTEK® Shower Monitor©, on shower water end
use properties.
The key objectives of this research are to:
Determine baseline water consumption end uses for a sample of households;
Establish baseline shower end use event characteristics (e.g. volume, duration, flow
rate) for 151 households in the Gold Coast residential end use study;
Evaluate the water savings potential of the WaiTEK® Shower Monitor© in a sub-
sample of households participating in the GCWSEU study;
Determine households’ response to the alarming visual display device through reduced,
or otherwise, shower durations or flow rate;
Quantify water and energy savings (i.e. hot water for showering purposes) achieved in
the sub-sample;
Model the payback period and annualised return for the device; and
Model the monetary and non-monetary benefits achievable from the citywide
implementation of the device.
Research outcomes provide water authorities and government officers with the decision support
systems to accurately predict the monetary and non-monetary benefits of installing such
alarming visual display devices; ultimately preserving water sustainability. The research method
adopted to achieve the above mentioned objectives are described below.
8.4 Research Method
The greater GCWSEU study participants (n=151) were recruited through a multi-staged process
of letters and door knocking. Selection of participants was based on a number of criteria
including: household ownership status (renting/owning) and household makeup; willingness to
be part of the research for a period of two years; acceptance to having water consumption
monitored over period; several questionnaire surveys; involvement in a range of potential
interventions; and involvement in a household water fixture/appliance stock audit. It should also
be noted that historical household volumetric readings were analysed for the consenting sample
to ensure that they are representative of Gold Coast City.
Upon completion of recruitment, the existing standard residential water meters were replaced
with high resolution water meters and data loggers to obtain end use water consumption data.
Chapter 8: Alarming visual display monitors affecting shower end use water and energy conservation
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The modified Actaris CTS-5 water meters pulse at a rate of 72 counts per litre of water
consumed; this equates to an individual recording every 0.014 L of water use. Aegis DataCell
D-CZ21020 data loggers were connected to water meters to record water consumption. Data
loggers were set to record information every ten seconds over a two week period. This resulted
in fourteen days of end use data for each household. Trace Wizard© software was utilised to
synthesise data into water end uses. This software provides the analyst with powerful processing
tools and a library of flow trace patterns for recognising a variety of residential fixtures. Once
the raw data has been downloaded from the data logger and processed, it can then be loaded into
Trace Wizard©. This software displays the data via a flow rate verse duration graph, whereby
any consistent flow pattern or event can be isolated, quantified and categorised based on an
established series of end use templates with specific information regarding a particular
household’s water usage patterns. Summary data for each water event is then calculated,
including, duration, volume, peak flow rate, mode flow rate, mode flow frequency, as well as
start and stop times for each episode. The software also has the ability to recognise two
simultaneous events. Once analysis has been completed, the file is converted to a database
format, whereby a complete registry of end use event information is stored. For the purposes of
this study, this database allowed researchers to create relative and cumulative frequency
distributions for shower end use event durations, volumes and flow rates.
The baseline data utilised in this paper was collected during winter 2008. During this time there
were no water restrictions in place on the Gold Coast as its primary water source (i.e. Hinze
Dam) was higher than 95% capacity. In total, the 151 monitored households included 38 single
reticulated and 113 dual reticulated water supplies. It should be noted that recycled water was
not supplied to the dual reticulated region during the monitoring period as the treatment plant
had not been commissioned. Thus, potable water was supplied to the appropriate end uses (i.e.
toilet and selected outdoor taps), which in the future (late 2009) will be supplied by recycled
water. Shower end use is only ever supplied by potable water, thus the affect of dual reticulation
has no bearing on the study’s objectives and subsequent outcomes.
In addition to monitoring water consumption, questionnaire surveys soliciting descriptive
information were developed and distributed to all the sample households. Surveys were
conducted to solicit household demographic information, including: (1) household address and
region; (2) resident numbers, gender, age, employment, weekly income, education status and
relationship of people within the house; and (3) household ownership status. Household stock
surveys were also conducted to ascertain the nature of water fixtures and appliances as well as
hot water heating systems.
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A sub-sample from the 151 households in the GCWSEU study was recruited to participate in
the herein mentioned shower monitor retrofit study. A total of 49 households consented to be
apart of this aligned sub-study and have shower monitors fitted to their utilised showers. The
initial sub-sample total water consumption and shower end use data, along with their socio-
demographic statistics was screeded to ensure that the final selected sub-sample was as
representative of the population as possible (given the feasible sample size). Five consenting
households were removed as the initial sub-sample was over represented by retired couples.
Upon completion of the recruitment and sample screening process, a total of 44 households
were included in the sub-sample, and all of their utilised showers were fitted with the alarming
visual display device (Figure 8-1) that was locked to a 40L shower event (i.e. based on a 5
minute shower at a flow rate of 8L/min). The device was set to alarm after the 40L volume was
consumed so individuals would know when it was time to get out of the shower. The monitor is
programmed to automatically turn on once water is flowing through the shower. The monitor
displays a bar graph which decreases over time of water consumption. Monitors were also set
for a delay time of 1 minute. The delay time is the time in which the person must wait between
showers so that the monitor can reset itself. If a person starts another shower before the 1 minute
is over, the monitor will start beeping. The shower monitors were all locked with a 4-digit pin
code that was retained by the researchers for study period to ensure that settings were not
changed. The monitor does not control the shower in any way. Instead, its purpose is to help
families reduce water and energy costs by providing the information necessary for them to
shower efficiently. Ultimately, the participants have the choice of getting out of the shower
when the beeping occurs or to simply ignore it and continue showering. Specifically, the device
aims to educate families on sensible water consumption by empowering the consumer with real-
time information rather than constructing a military type environment.
Following the implementation of the shower monitors water end use data was collected over a
two week period in winter 2009, following the same process described above for the baseline
GCWSEU study. Analysed and verified trace analysis files for the pre- and post- shower
monitor retrofit were converted to database files whereby all shower events could be listed and
categorised based on event duration (based on event start and end time), volume or flow rate.
Relative and cumulative frequency distributions for sub-sample shower event characteristics
were then established along with as their associated mean, median and standard deviation
values. This data analysis process enabled shower event comparisons to be conducted pre- and
post- installation of the shower monitor. The baseline water consumption end use results, with a
particular focus on shower end use is presented in the next section, followed by the comparative
assessment pre- and post- implementation of the shower monitor.
Chapter 8: Alarming visual display monitors affecting shower end use water and energy conservation
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8.5 Baseline Water Consumption End Use Analysis
The break down of end use water consumption for the sampled households in the Gold Coast
(N=151) for winter 2008 is presented in Figure 8-2. Readers should again note that recycled
water is not currently supplied to the dual reticulated region as the treatment plant was not
commissioned. Thus, potable water was being supplied to appropriate end uses (i.e. toilet and
outdoor taps) which in the future (i.e. late 2009), will be supplied by recycled water. Due to this
fact, the cost for this water is the same as potable (i.e. no reduced pricing) and the water
restriction level remains constant between the regions. Moreover, no awareness campaign was
launched to encourage the uptake of recycled water in the dual reticulated region. Considering
this current situation and the limited variance between the applicable end uses of single and dual
reticulated households, the two datasets was treated as one sample for the purpose of this
present study (Willis et al., 2009a). Once recycled water is commissioned, it is expected that
there will be a clear distinction between the single and dual reticulated households,
predominately due to higher irrigation use within the latter sample.
Irrigation (Total)18.6 L/p/d
12%
Leak (Total)2.1 L/p/d
1%
Clothes Washer30.0 L/p/d
19%
Toilet (total)21.1 L/p/d
13%
Dishwasher2.2 L/p/d
1%
Bathtub6.5 L/p/d
4%
Tap27.0 L/p/d
17%
Shower49.7 L/p/d
33%
Figure 8-2 Sample end use break down: winter pre-retrofit (n=151)
According to Figure 8-2, the average baseline consumption for the sampled Gold Coast
households (n=151) was 157.2 litres per person per day (L/p/d). The highest end use was
showering, with each person consuming almost 50 litres of water a day or 33% of total use.
Clothes’ washing was the next highest end use at 30 L/p/d or 19% of total consumption. Tap
use, toilet flushing and irrigation follow with end use percentages of 17%, 13% and 12%,
respectively. Bath use, dishwashing and leaks make up a small component of water end use with
Domestic End Use Investigation: WDM and Dual Reticulation, R.M. Willis (2010)
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percentages ranging from 1% to 4%. Many of the prior mentioned end use studies show
irrigation consuming a higher proportion of the total household water consumption, especially
in summer months. The Gold Coast is located in a region experiencing a humid subtropical
climate, where irrigation consumption is generally lower in the wet summer months than other
seasons. Moreover, the study was conducted just after a period of drought where irrigation was
severely restricted; after this drought there was a culture shift whereby brown grass was
accepted in dry periods.
Figure 8-3 demonstrates the descending order distribution of the end use water consumption
break down for each of the measured 151 households. It also shows the proportion of sampled
households within each of the Queensland Water Commission (QWC) restriction regime
categories, upon which the Gold Coast Local Government Area (Capati et al.) must conform
(i.e. Target 140: Extreme Level; Target 170: High Level; Target 200: Medium Level; and
Target 230: Permanent Water Conservation Measures). The average total consumption of
sampled households in the study and distribution are representative of the Gold Coast at the
time of study.
Figure 8-3 Sample household end use distribution: winter pre-retrofit (n=151)
Whilst there were no restrictions at the time on the Gold Coast, almost half of the research
population (46%) consumed less than 140.0 L/p/d. Water consumption is highly varied between
individual households. The highest per capita use equated to 390.0 L/p/d whilst the lowest use
was as small as 38.4 L/p/d. This substantial difference between the highest and lowest per capita
consumption volumes demonstrates that a representative spread of water users is present in this
research sample. Figure 8-3 illustrates that shower end use in many households is the major
contributor to the total water consumption level. The extracted water end use distribution of this
specific activity is presented in Figure 8-4.
0.00
50.00
100.00
150.00
200.00
250.00
300.00
350.00
400.00
450.00
Household ID
Lit
res
/Pe
rso
n/D
ay
Leak (Total)
Irrigation (Total)
Toilet (Total)
Bathtub
Dishwasher
Tap
Shower
Clothes Washer
Queensland Water Commission Target Ranges (140, 170, 200 and 230)>230 L/p/d 201 - 230 L/p/d 171 - 200 L/p/d 141 - 170 L/p/d >140 L/p/d
21 homes(14%)
13 homes(9%)
20 homes(13%)
27 homes(18%)
70 homes(46%)
Chapter 8: Alarming visual display monitors affecting shower end use water and energy conservation
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Figure 8-4 Sample shower end use distribution: winter pre-retrofit (n=151)
Figure 8-4 shows that 13% of the sampled households consumed 30% of the total volume of
water utilised for showering purposes. This highlighted sub-sample (13%) constitutes a non-
linear shower use pattern as opposed to the remaining research population (87%) which shows a
reasonably linear rate of change in consumption. The distribution of shower use, as illustrated in
the Figure 8-4 insert, demonstrates that half of the population used less than 40 L/p/d of water
for showering which is equivalent to a 5 minute shower at 8L/min. For the remaining categories,
37% of households use between 41 to 80 L/p/d with the high user group (13%) consuming on
average more than 80 L/p/d in the shower. The high level of shower end use consumption and
its variability identified in the baseline study instigated the design for the shower monitor
intervention study described in the next section.
8.6 Visual Display Monitors Influencing Shower End Use Events
As described in the research method, the categorised shower end use event features were
compiled into a database for both the pre- and post- shower monitor implementation. Three of
the shower event features, namely, event duration, volume and flow rate, were summarised in a
clustered relative and cumulative frequency distribution histogram. Moreover, the mean and
median values for these features pre- and post- implementation of the shower monitor were
determined and compared. It should be specially noted that changes in flow rates before and
after shower monitor retrofits were of concern since the study sought to understand whether
households would reduce flow rates to maximise their shower duration before an alarm
sounded. As mentioned previously, readers should note that the fixed 40L volume is a function
of flow rate and duration and the device compensates for variation in these variables. The
0.00
50.00
100.00
150.00
200.00
250.00
Household ID
Lit
res
/Pe
rso
n/D
ay
(L
/p/d
ay
)
Daily Per Capita Distribution: Shower
10%
40%
19% 19%
13%
0%
5%
10%
15%
20%
25%
30%
35%
40%
45%
<20 21-40 41-60 61-80 >80
L/p/d
Re
lati
ve
Fre
qu
en
cy
(%
)
13% of homes use 30% of total shower water
13% of homes use 30% of total shower water
Domestic End Use Investigation: WDM and Dual Reticulation, R.M. Willis (2010)
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following sections provide the results and discussion relating to changes in shower duration,
volumes and flow rates, respectively.
8.6.1 Influence on shower duration
The change in the relative and cumulative frequency distribution for shower event durations is
illustrated in Figure 8-5. The figure illustrates that post installation there is a much higher
frequency of shower event durations between 1-7 minutes. It appears that many of the 7-15
minute shower events have moved into these lower interval categories. Given that the shower
monitor was locked to beep after 40L with approximate shower duration of 5 minutes it seems
that many home owners still shower for a minute or two after the beeping commences. The data
shows that households that were originally water conscious have further reduced their
consumption with a significant increase in showers in the 1-4 minute intervals. Whilst the
frequency of shower events greater than 10 minutes has more than halved from 14% to 6.4%,
the results indicate that some residents still continue to have excessively long showers even with
a visual display and alarm present.
Nonetheless, as indicated in the inset of Figure 8-5, the mean shower duration reduced from
7.19 to 5.86 minutes, which equates to a saving of 1 minute and 20 seconds (i.e. 1.34 minutes)
or 18.6%. An independent sample t-test for equality of means was undertaken to test the
significance of mean differences (Table 1). Independent rather than paired sample t-tests were
undertaken since the total number of shower events in the sub-sampled households’ pre- and
post- retrofit was obviously different and were treated as two samples. According to Levene’s
test for equality of means the samples were treated as having unequal variances. The
independent unequal variance sample two-tailed t-test resulted in a very high t-value of 6.62 (p
< 0.0005) indicating significant mean value differences. The lower difference between the
median shower event durations (i.e. 50 seconds) indicates that the long tail of high duration
events increased mean values. This fact is reinforced by the samples standard deviation being
very high (i.e. 4.49 minutes pre-retrofit and 3.55 minutes post-retrofit), however, noticeably
reduced post retrofit of the shower monitor. In summary, the shower monitor reduced the time
spent in the shower, but not to the extent expected with the device alarming at 5 minutes based
on the set 8L/min flow rate. Residents may have decided to reduce their typical shower flow
rate to yield a longer event duration (i.e. reducing flow rate below 8L/min will increase duration
beyond 5 minutes before alarm sounds); this will be explored later.
Chapter 8: Alarming visual display monitors affecting shower end use water and energy conservation
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Figure 8-5 Sample pre- and post- monitor retrofit shower event duration frequency distribution
8.6.2 Influence on shower volumes
Figure 8-6 details the relative and cumulative frequency of shower event volumes pre- and post-
implementation of the shower monitor. The figure illustrates that even prior to the
implementation of the shower monitor, 39.9% of the shower event volumes were less than 40L
increasing to 59.3% after the implementation of the shower monitor. It appears that shower
users already practicing water conservation went even further in reducing shower volumes as
many of the 30-40 L events probably reverted to the 10-20 L or 20-30 L intervals. Another
interesting characteristic of the histogram is the reduction in shower events in the 60-100 L
range post-retrofit but the slight increase in the 40-50 L interval. It appears that a reasonable
proportion of residents that previously showered within the 50-100 L range now responded
within a minute or so of the alarm and finished their shower. Unfortunately, even after the
shower monitor retrofit 4.5% of the shower event volumes were greater than 100 L. Again, it is
evident that some residents having very high consumption shower events were not perturbed by
the shower display and alarming device. As indicated in the inset of Figure 8-6, the mean
shower event volume decreased from 57.37 L to 41.97 L after the shower monitor retrofit. This
resulted in a saving of 15.40 L per shower event or 27%. An independent sample t-test for
equality of means was undertaken to test the significance of mean differences (see Table 8-1).
0
5
10
15
20
0-1
1-2
2-3
3-4
4-5
5-6
6-7
7-8
8-9
9-10
10-1
1
11-1
2
12-1
3
13-1
4
14-1
5
15-1
6
16-1
7
17-1
8
18-1
9
19-2
0
Mor
e
Duration event clusters (minutes)
Rel
ativ
e fr
eque
ncy
(%)
0
20
40
60
80
100
Cum
ulat
ive
freq
uenc
y (%
)
Pre-Retrofit R.F
Post-Retrofit R.F
Pre-Retrofit C.F
Post-Retrofit C.F
Duration pre retrofit:Mean = 7.19 minsMedian = 6.00 minsDuration post retrofit:Mean = 5.86 minsMedian = 5.17 mins
- 194 -
Table 8-1 Independent sample t-test for equality of means
Event description
Variance assumption
Levene's test for equality
of variances
t-test for equality of means
95% confidence
interval of the
difference
F Sig. t df Mean
(pre-retrofit) Mean
(post- retrofit)
Mean difference
(pre- vs. post)
Sig.
(2-tailed)
Std. error
difference Lower Upper
Assumed 27.14
.000 6.70 1631 7.19 5.86 1.34 .000 .200 .95 1.73 Duration (Giurco et al.) Not assumed 6.62 1469 7.19 5.86 1.34 .000 .202 .94 1.73
Assumed 39.34
.000 9.11 1632 57.37 41.97 15.40 .000 1.691 12.08 18.72 Volume (L)
Not assumed 8.93 1338 57.37 41.97 15.40 .000 1.724 12.02 18.78
Assumed 14.98
.000 5.82 1632 9.98 8.98 1.00 .000 .171 .66 1.33 Flow rate (L/min)
Not assumed 5.78 1556 9.98 8.98 1.00 .000 .172 .66 1.33
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According to Levene’s test for equality of means the samples were treated as having unequal
variances. The independent unequal variance sample two-tailed t-test resulted in a very high t-
value of 8.93 (p < 0.0005) indicating significant mean value differences. Of note also is that the
median shower event fell below the 40 L target after the implementation of the shower monitor
(i.e. 36.38 L). The improvement in shower event volumes is reinforced by the significant drop
in standard deviation from 40.36 L to 27.33 L per event (i.e. 13.03 L reduction). The results for
shower event volumes indicate that the shower monitor had a good degree of impact on
reducing shower water consumption to a mean value close to the targeted 40 L; this is a
promising result considering that the tail of high volume showers evident in the relative
frequency distribution histogram (Figure 8-6).
Figure 8-6 Sample pre- and post- monitor retrofit shower event volume frequency distribution
8.6.3 Influence on shower flow rates
Figure 8-7 details the shower event flow rate relative and cumulative frequency distribution for
the sampled households. Cumulative flow rate frequency distributions between 0-8 minutes
increased from 40.7 to 52% indicating that some residents were aware that reduced flow rates
would increase their shower duration before the visual display monitor alarmed. In general, the
relative frequency distribution histogram provides some evidence that residents have slightly
lessened flow rates from their baseline. Exactly 1 L/min or 10.2% was reduced from the mean
flow rate post shower monitor implementation (i.e. 9.78 to 8.78 L/min) and a slightly lower
reduction in the median flow rate was evident. An independent sample t-test for equality of
means was undertaken to test the significance of mean differences (see Table 8-1). According to
0
5
10
15
20
25
0-10
10-2
0
20-3
0
30-4
0
40-5
0
50-6
0
60-7
0
70-8
0
80-9
0
90-1
00
100-
110
110-
120
120-
130
130-
140
140-
150
Mor
e
Volume event clusters (litres)
Rel
ativ
e fr
eque
ncy
(%)
0
20
40
60
80
100
Cum
ulat
ive
freq
uenc
y (%
)
Pre-Retrofit R.F
Post-Retrofit R.F
Pre-Retrofit C.F
Post-Retrofit C.F
Volume pre retrofit:Mean = 57.37 LitresMedian = 46.38 LitresVolume post retrofit:Mean = 41.97 LitresMedian = 36.38 Litres
Domestic End Use Investigation: WDM and Dual Reticulation, R.M. Willis (2010)
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Levene’s test for equality of means the samples were treated as having unequal variances. The
independent unequal variance sample two-tailed t-test resulted in a very high t-value of 5.78 (p
< 0.0005) indicating significant mean value differences. In summary, the relative frequency
distribution provides an indicator that some residents understood how the device worked and
reduced their flow rates in order to extend shower duration. Additionally, the mean as well as
median flow rates are still above the targeted 8 L/min strived for but have nonetheless reduced
along with variance. The following section provides a discussion on the water and energy
savings, monetary savings and payback period, and non-monetary benefits, derived from the
implemented shower monitoring device.
Figure 8-7 Sample pre- and post- monitor retrofit shower event flow rate frequency distribution
8.7 Resource Conservation and Financial Modelling
8.7.1 Water and energy conservation
As determined in this study the shower monitor interventions reduced the sub-samples shower
event volume by 15.40 L or 27%. Based on the Gold Coast end use study sample (N=151) as
well as the post-implementation sub-sample end use data, the average number of shower events
per household per day was determined to be 2.65. Therefore, given the 15.40 L saving per
shower event and mean 2.65 shower events per household per day, a daily 40.85 litres per
household per day (L/hh/d) or 14.91 kilolitres per household per annum (kL/hh/a) saving can be
achieved. There are approximately 200,000 occupied dwellings in Gold Coast City.
Conservatively estimating that 50% of the determined water savings are achieved in the cities
dwelling stock due to a range of factors (e.g. household size, etc.), a total citywide annual
0
5
10
15
20
25
0-1
1-2
2-3
3-4
4-5
5-6
6-7
7-8
8-9
9-10
10-1
1
11-1
2
12-1
3
13-1
4
14-1
5
15-1
6
16-1
7
17-1
8
18-1
9
19-2
0
Mor
eEvent flow rate (litres/minute)
Rel
ativ
e fr
eque
ncy
(%)
0
20
40
60
80
100
Cum
ulat
ive
freq
uenc
y (%
)
Pre-Retrofit R.F
Post-Retrofit R.F
Pre-Retrofit C.F
Post-Retrofit C.F
Flow rate pre retrofit:Mean = 9.98 Litres/minMedian = 8.74 Litres/minFlow rate post retrofit:Mean = 8.98 Litres/minMedian = 7.90 Litres/min
Chapter 8: Alarming visual display monitors affecting shower end use water and energy conservation
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saving of 1.5 GL or 3% of total city consumption was determined. Put simply, water saved
through the installation of the alarming shower monitoring devices could fill 600 Olympic sized
swimming pools annually.
In addition to water savings, the energy cost associated with hot water often utilised for
showering is high. DeOreo and Mayer (2001) determined that 73.1% of shower end use water
consumption is hot water, heated through electric, gas, solar or combination fuel source hot
water systems. Therefore, 10.90kL (i.e. 14.91 kL/hh/a × 0.731) of hot water is saved annually
through the shower monitor device. The Specific Heat Capacity value for water is 4.187
kilojoules per litre (kJ/L). This means that 4.187 kJ/L of energy is required to raise the
temperature of one litre of water (1 kg mass) by one degree Celsius at standard temperature and
pressure. The ability of any of the heating systems to deliver this heat energy is governed by its
efficiency. If a system requires twice as much energy to what can be extracted in the form of hot
water then the system has an efficiency of 50%. Systems range in efficiency from close to 50%
for some gas systems to 99% for instantaneous gas. Based on the energy efficiency of heating
systems, Specific Heat Capacity, 10.90kL saving in hot water, and heating to increase the water
temperature by 45 degrees Celsius, total energy saved ranged from: (a) 665 Mega joules per
household per annum (MJ/hh/a) for a heat pump with electric backup system; to (b) 825-
1027MJ/hh/a for solar with electric/gas backup system; to (c) 2074-2738 MJ/hh/a for an electric
system; to (d) 2600-3541 MJ/hh/a for gas systems. In the sub-sample of households
participating in the end use study, the majority of households had traditional electric hot water
storage systems but there were still a few with other system types such as solar and heat pump.
The incentivised solar panel rebate programs offered by the government may have had some
influence on the uptake of solar systems. Based on the heating system stock in each of the
respective sub-sample households and the calculated energy savings due to reduced hot water
consumption, an average annual energy saving per household was determined as 2168 MJ/hh/a
or 602 kilowatt hours per household per annum (kWh/hh/a). The Gold Coast citywide
consumption of energy in 2005 was 7.1 petajoules (PJ) increasing at an annual rate of 5.73%
(Australian Bureau of Agricultural and Resource Economics (ABARE), 2006). Based on this
base year energy use and the annual growth in power consumption, the 2009 energy use was
estimated at 8.9 PJ. As above, conservatively estimating that 50% of the determined water
savings are achieved in the cities 200,000 dwelling stock, due to a range of factors (e.g.
household size, etc.), a total citywide annual associated energy saving of 0.22 PJ or 2.4% of
total city energy consumption was determined.
8.7.2 Monetary savings and capital pay-back
Based on the study sample, water and energy pricing information specific to Gold Coast City,
and other economic indicators, a range of variables were extracted in order to model the life
Domestic End Use Investigation: WDM and Dual Reticulation, R.M. Willis (2010)
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cycle monetary savings resulting from the shower monitor device and the payback period. It
should be noted that both water and energy savings have been modelled as these are the two
direct monetary benefits evident from reduced shower water consumption. Moreover, the
modelling is based on the situational context of Gold Coast City, Australia, where the study was
conducted.
The variables applied to model monetary savings and capital pay-back are as follows. Annual
water savings derived from this study were determined as 14.91 kL/hh/a as determined above.
Gold Coast Water currently (2009/2010) charges a water consumption rate of A$2.24/kL
(US$2.00/kL; 1AUD=0.8904USD; 25/2/2010) which equates to an annual monetary saving of
A$33.40 (US$29.74) associated with the shower monitor. A water price inflation rate of 10%
was chosen for the increase in the water consumption charge as the cost of water in Gold Coast
City, and across most of Australia, has been raising excessively over the last five years due to
widespread drought forcing government to invest heavily in water supply infrastructure
investments (e.g. desalination plants, dams, pipelines, etc.).
Electricity prices for Gold Coast City domestic consumers are currently A$0.18843/kW
(US$0.16778/kW) and A$0.11319/kW (US$0.10079/kW) for peak and off-peak rates,
respectively (2009/2010 rates). Gas prices are A$0.02046/MJ (US$0.01822/MJ) for small
volume users decreasing to A$0.01760/MJ (US$0.01567/MJ) for higher volume users
(2009/2010 rates). Given the energy savings presented above for the different heating source
systems in the sub-sample and base year energy tariffs in Gold Coast City, the costs to heat
water ranged from A$1.74/kL (US$1.55/kL) for a solar system with gas boost to A$7.90/kL
(US$7.03/kL) for an off-peak electric storage system. Based on the costs to heat each kilolitre of
water for each respective heating system in each sampled household and the 10.90kL of hot
water saved, an annual average energy saving for the base year (2009/2010) was calculated as
A$62.78/hh/a (US$55.90/hh/a). Similarly to water, energy cost inflation has increased at a rate
in excess of 10% per annum over the last five years and is expected to continue due to costs
associated with the governments’ climate change policies. Thus, an energy inflation rate of 10%
was again selected for discounted cash flow modelling.
Therefore the base year combined water and energy savings determined in this study was
A$96.18/hh/a (US$85.64/hh/a) (water cost savings = A$33.40/hh/a and energy cost savings =
A$62.78/hh/a). With respect to the capital cost of the shower monitor device and associated
installation costs, the average number of shower monitors installed in households was 1.3 at a
purchase price of A$75 (US$66.78) per device. Installation of the device could be easily
undertaken by the home occupier but for this study a professional plumber was employed
costing A$66 (US$58.77) per household, regardless of number of monitors installed. This
Chapter 8: Alarming visual display monitors affecting shower end use water and energy conservation
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equated to an average total capital outlay of A$163.50 (US$145.58) per household to yield the
mean 14.91 kL/hh/a water saving. There are no ongoing operational costs for the device as their
battery life is around 10 years which was considered the usable life of the device.
The payback period is the time it takes for the cumulative water and energy savings to cover the
capital investment of the shower monitor. A discount rate of 3% has been applied which
indicates a general cost of money in the Australian context. Considering the capital investment
cost, first year water and energy savings determined, water and energy price inflation as well as
the discount factor, the payback period for the herein mentioned alarming visual display shower
monitoring device was determined as 1.65 years. Moreover, over a 10 year life cycle period, the
annualised return of investment from conservation savings generated by the capital cost of the
shower monitor equates to 23.3%. This attractive payback period and annualised return provide
strong evidence that alarming visual display devices in the shower represent an attractive
investment.
In addition to the monetary savings listed above there are a number of non-monetary benefits
associated with resource consumption feedback devices such as the shower monitor discussed
herein. These are discussed briefly in the next section.
8.7.3 Wider non-monetary benefits
The modelled financial benefits and payback period for the alarming visual display monitor are
substantial enough to justify their implementation across all of the urban centres in Australia as
well as other urban settlements where water and energy resources are no longer secure and are
rapidly increasing in price. In addition to the monetary benefits for householders for installing
the device, there are a range of other non-monetary benefits for greater society. Firstly, reduced
water and energy requirements of an existing population could enable the deferment of both
water and energy supply infrastructure (e.g. dams, pipeline duplications, power plants,
desalination plants, etc.). Reductions in demand for such infrastructure will lessen the current
inflationary pressures on prices. Lessened water consumption also means lower energy costs
associated with urban water storage, production and distribution (e.g. pumping, water quality
processing, desalination, etc.).
Another benefit of particular mention in the current century is climate change adaptation.
Centralised water supply systems and the predominant non-renewable sources of power for
heating water create substantial carbon emissions which need to be reduced to limit climate
change impacts. Finally, and most importantly, the business management philosophy ‘that if
can’t measure it, you can’t manage it’ has transferable relevance to resource consumption in a
resource constrained world. Resource consumption awareness devices such as the one evaluated
Domestic End Use Investigation: WDM and Dual Reticulation, R.M. Willis (2010)
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in this study assist resource users to take ownership of their usage and individually tackle their
own and/or society driven conservation goals; ultimately helping to reduce the ecological
footprint of the built environment.
8.8 Conclusions and Futures Directions
This paper presented findings from the GCWSEU study, namely, the evaluation of the influence
of alarming visual display devices on shower end use durations, volumes and flow rates.
Moreover, water and energy conservation modelling was conducted to ascertain monetary
benefits as well as the payback period of such devices. Broader non-monetary benefits were also
explored. The study determined that the shower visual display monitors instigated significant
water and energy savings and have a respectable payback period of less than two years. The
study provides empirical evidence to support the widespread implementation of alarming visual
display shower monitors, and also provides a methodology to explore the effect of a range of
other water and energy end use monitors. Through providing households with dynamically
updated visual displays on a range of behaviourally influenced water and energy appliances and
fixtures, residents will be better informed of their consumption rates and thus feel empowered to
reasonably limit and/or maintain control over their resource consumption.
This study also illustrated that smart water metering is vital for understanding water end uses,
particularly for understanding the characteristics of shower end use events. Future research
directions associated with this component of the research program, include: (1) to examine the
change in shower water conservation practices with time (i.e. longitudinal study); (2) conduct
interviews with residents participating in the study to explore how they responded to the device;
(3) examine the effect of visual display monitors and/or alarming devices on other domestic end
use events (e.g. tap fixtures); (4) evaluate shower event water temperature relative and
cumulative frequency distributions to better model heating requirements; (5) directly monitor
water heating power consumption associated with shower end use events; and (6) further model
water and energy conservation with a greater sample across different Australian urban centres.
Future research associated with the GCWSEU study is also discussed as follows. Firstly,
research is currently underway to examine the predictive power of descriptive (i.e. education
level, income, etc.), infrastructure (i.e. stock survey) and qualitative variables (i.e. attitudes,
perceptions, etc.) on water end use in domestic households. Secondly, recycled water will be
commissioned and supplied to residents in the Pimpama Coomera region of Gold Coast City in
late 2009, and a summer end use data collection phase (December-February 2009) will be
undertaken to establish the uptake of recycled water at the end use level. This, combined with
previous end use data, will provide ‘before and after’ end use results of the implementation of
Chapter 8: Alarming visual display monitors affecting shower end use water and energy conservation
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recycled water. This data will assist in verifying end use assumptions made in the planning
phases of the Pimpama Coomera development. Thirdly, the impact of education or awareness as
a demand management measure will also be tested within the study. Residents participating in
the research will be provided with their unique end use data as well as targeted suggestions for
reducing high end uses within their homes. This study seeks to establish if water consumption
behaviours alter as a result of the provided information.
Another component of the research program is the establishment of diurnal patterns for both
single and dual reticulated households in the Gold Coast. Dual reticulated households will have
two separate diurnal patterns for both potable and recycled water demand. Such diurnal patterns
will be determined at an end use level, thus providing a comprehensive understanding of water
consumption at a given time, which provides indications on how to affect peak loading to the
urban water system. The above stated components of the research program will culminate in the
development of a comprehensive domestic end use model for the Gold Coast as well as
evidence that supports, or otherwise, the effect of WDM measures (principally dual reticulation
and awareness/education initiatives) for conserving previous precious potable water supplies.
Such models and findings could be adapted for both national and international applications and
policy formulation.
8.9 References
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Arroyo E., Bonanni L. & Selker T. (2005) Waterbot: exploring feedback and persuasive techniques at the sink. In: Proceedings of the SIGCHI 2005 conference on human factors in computing systems. Portland, pp. 631-639.
Australian Bureau of Agricultural and Resource Economics (Australian Bureau of Agricultural and Resource Economics (ABARE)). (2006) Australian energy consumption by industry, 1974–75 to 2004–05, June. Canberra.
Bechtel RB., Corral-Verdugo V. & Pinheiro JQ. (1999) Environmental belief systems: United States, Brazil, and Mexico. Journal of Crosscultural Psychology, Vol 30, pp. 122–128.
Birrell B., Rapson V. & Smith F. (2005) Impact of Demographic Change and Urban Consolidation on Domestic Water Use. Melbourne: Water Services Association of Australia Inc.
Britton T., Cole G., Stewart R. & Wisker D. (2008) Remote diagnosis of leakage in residential households. Water, Vol 35:6, pp. 89-93.
Chambers VK., Creasey JD., Glennie, EB., Kowalski M. & Marshallsay D. (2005) Increasing the value of domestic water use data for demand management - summary report. Wiltshire: WRc plc.
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Commonwealth Scientific and Industrial Research Organisation (CSIRO). (2007) Climate Change in Australia: Technical Report 2007. Melbourne: CSIRO.
Corral-Verdugo., Bechtel R. & Fraijo-Sing B. (2003) Environmental beliefs and water conservation: An empirical study. Environmental Psychology, Vol 23, pp. 247–257.
Darby S. (2006) The Effectiveness of Feedback on Energy Consumption. Environmental Change Institute, University of Oxford.
DeOreo WB. & Mayer PW. (2001) The End Uses of Hot Water in Single Family Homes from Flow Trace Analysis: Aquacraft Inc. Report, http://www.aquacraft.com.
Dobson JK. & Griffin JD. (1992) Conservation Effect of immediate electricity cost feedback on residential consumption behaviour. In: Proceedings of the 7th ACEEE Summer Study on Energy Efficiency in Buildings. Washington, DC, pp. 33-35.
Fischer C. (2008) Feedback on household electricity consumption: a tool for saving energy? Energy Efficiency, Vol 1:1, pp. 79-104.
Hauber-Davis G. & Idris E. (2006) Smart water metering. Water, Vol 33:3, pp. 56-59.
Hearn B. (1998) Benchmarking water use on farm: if you don’t measure it, you can’t manage it. In: Proceedings of the 9th Australian Cotton Conference. Gold Coast; 1998. pp. 519-529.
Idris E. (2006) Smart metering: a significant component of integrated water conservation system. In: Proceedings of the 1st Australian Young Water Professionals Conference. Sydney: International Water Association.
Inman D, Jeffrey P. (2006) A review of residential water conservation tool performance and influences on implementation effectiveness. Urban Water Journal, Vol 3:3, pp. 127 - 143.
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Taverner Research. (2005) Survey of Household Water Attitudes. Surry Hills: Taverner Research.
Turner A., White S., Beatty K. & Gregory A. (2005) Results of the largest residential demand management program in Australia. Sydney: Institute for Sustainable Futures, University of Technology.
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Ueno T., Sano F., Saeki O. & Tsuji K. (2006) Effectiveness of an energy-consumption information system on energy savings in residential houses based on monitored data. Applied Energy, Vol 83:2, pp. 166-183.
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Chapter 9
Pimpama-Coomera dual reticulation end use study: pre-commission baseline,
context and post-commission end use prediction
This chapter is a reformatted version of a peer-reviewed article by the author published in the
Journal of Water Science and Technology: Water Supply (2010) Vol 10:3, pp. 302-314, DOI:
10.2166/ws.2010.104.
9.1 Abstract
The Gold Coast Water Pimpama Coomera dual reticulation schemes’ recycled water supply will
be online in late 2009. In an attempt to achieve better estimates on both potable and likely
recycled water end uses within this region, this paper presents a predictive model that utilises a
range of input parameters, including: current use in the Gold Coast and the Pimpama Coomera
regions at both a bulk billing and end use level; recycled water use at other dual reticulated
schemes; and questionnaire survey of residents water source preferences for outdoor uses. Prior
to the commissioning of recycled water, potable water is supplied through the recycled water
pipelines. Water end use consumption analysis from the recycled water smart meter indicates
that this supply source currently provides 20% of total household use with the majority of use
being for toilet flushing. However, a range of factors have attributed to this low baseline level
with evidence collected in this study indicating that higher recycled water consumption rates
will occur once this supply line has been commissioned; largely due to the lower cost and fewer
restrictions placed on this water source for discretionary outdoor purposes. The weighted
amalgamation of a range of baseline adjustment factors assisted in the prediction of post-
commissioning end uses for the Pimpama Coomera dual reticulated region. The predictive
model indicated that recycled water end uses would account for 53 litres per person per day or
30.6% of total household consumption. The paper concludes with a brief overview of Phase 2 of
the study which aims to compare actual post-commission end uses with the baseline situation
and prediction, as well as the development of a robust end use model for dual reticulated
regions.
Chapter 9: Pimpama-Coomera dual reticulation end use study: pre-commission baseline, context and post-commission end use prediction
- 205 -
9.2 Australian Dual Reticulated Communities
Long lasting droughts in various regions, increasing populations and demand on fresh or potable
water has driven the need, especially in Australia, to increase the reuse, recycling and
purification of water. The Australian National Water Initiative encourages water conservation
and the reuse of wastewater and stormwater (COAG, 2009). Hurlimann and McKay (2006a)
state that the focus of water reuse in Australia is through the application of dual reticulated
water supply in new developments. Recycling or reclaiming water for reuse in specified end
uses is well accepted as an effective and sustainable measure of water conservation (Anderson,
1996; Marks and Zadoroznyj, 2005; Po et al., 2005). Recycled water in dual reticulated regions
is generally supplied for toilet flushing and outdoor uses with the exception of filling pools and
spas (Gold Coast Water, 2004; Marks and Zadoroznyj, 2005; Kidson et al., 2006). Nationwide,
residential water restrictions which limit outdoor use exemplify that external water use is
considered nonessential (Syme et al., 2004) even though regions such as Perth have recorded up
to 54% of total household consumption externally (Loh and Coghlan, 2003). Nancarrow et al.
(2002) carried out a longitudinal study to determine attitudes to water restrictions with
respondents indicating that they were supportive of regular low level restrictions (i.e. watering
2-3 days per week over summer) but not those of a permanent and highly restrictive nature (i.e.
no external water use or bucket use only for long periods). The implementation of recycled
water through dual reticulation gives households the freedom to irrigate externally and to enjoy
the benefits of their outdoor space.
Well maintained gardens and outdoor areas are understood to provide a range of benefits,
including: serving to facilitate human relationships (Bhatti and Church, 2000); physiological
and recreational benefits (Kaplan and Kaplan, 1990; Syme et al., 2004); provision a sense of
place (Sime, 1993); and they also demonstrate a reflection or extension of residents homes
(Bhatti, 1999). Research such as this encourages the application of dual reticulated schemes as
they remove the constraint of water restrictions and allow householders to enjoy and maintain
their outdoor living space to their liking, not to mention the benefits of reusing a once
considered ‘waste’ form of water. The reuse of waste water through centralised dual reticulation
schemes like that in Pimpama Coomera has a range of environmental advantages. These include
reducing the quantum of effluent disposal, improving the receiving water quality through
reducing the pollutants discharged into downstream water systems, and a reduced draw on the
water extracted from the fresh water system. On the downside, these schemes can be energy
intensive due to the energy required for the recycled water treatment processes, as well as the
additional pump energy required to distribute two water supply sources to the household
(Anderson, 2003; White and Turner, 2003). Overall, the provision of recycled water for
appropriate end uses is considered to be beneficial due to the diversification of supply sources
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of water for customers, the reuse of waste water and for minimising the impact of water
restrictions on the community.
In Australia, numerous residential developments adopting dual reticulation have been
implemented. Some of the more prominent schemes include Mawson Lakes (Adelaide), New
Haven Village (Adelaide), Rouse Hill (Sydney Water), Aurora (Melbourne), Marriott Waters
(Melbourne) and Pimpama Coomera (Gold Coast). Table 9-1 presents an overview of the
nation’s current dual reticulation schemes and estimates/actual savings from recycled water
implementation.
Table 9-1 Summary of dual reticulated schemes in Australia
Scheme Description Recycled water end uses
Predicted/actual potable water savings
Rouse Hill, Sydney (Sydney Water, 2008)
Online 2001 Will serve up to 36,000 homes Centralised supply system
Toilet & Outdoor uses
Predicted = 40% Actual = 35-40% reduction on total demand
Mawson Lakes, Adelaide (Hurlimann and McKay, 2006b)
Online 2005 Will serve up to 3500 homes
Toilet & Outdoor uses
Prediction = 50% of householder’s water demand (265 kL/year)
New Haven Village, Adelaide (Fearnley et al., 2004)
65 homes Toilet & Outdoor uses
Prediction = 30-40% Actual = 50%
Aurora (VicUrban), Melbourne (Baldwin, 2008)
8,500 lots Development onsite collection & reuse
Toilet & Outdoor uses
Prediction = Up to 45% (recycled water & conservation)
Pimpama Coomera, SEQ (Gold Coast Water, 2004)
Online end 2009 Will serve up to 45,000 homes Centralised supply system
Toilet & Outdoor uses
Prediction = 35-45%
Marriott Waters, Melbourne (Victorian Government, 2009)
Online February 2009 Currently 100 homes On completion 1000 homes Dual reticulated development supply
Toilet & Outdoor uses
Prediction = Up to 40%
Table 9-1 demonstrates that recycled water is well utilised in dual reticulated regions and that
predictions of uptake have been similar to those measured for mature schemes. Residents of
Rouse Hill use between 35-40% of their total household water consumption through recycled
water (Kidson et al., 2006; Sydney Water, 2008). Residents in New Haven Village in Adelaide
are using up to 50% of their total water consumption as recycled water (Fearnley et al., 2004).
Numerous dual reticulation schemes have been planned but measurements of the potable and
recycled water end use consumption have not yet been made or published. This study
investigates the end uses of the Pimpama Coomera (PC) scheme located in the Gold Coast,
Queensland with particular focus on the recycled water consumption component and break
down.
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9.3 Pimpama-Coomera Dual Reticulation Scheme
The Pimpama-Coomera Waterfuture (PCWF) Master Plan was developed to ensure sustainable
water consumption in the Gold Coast’s growing urban corridor. As observed in Table 1, PC is a
residential dual reticulated region with centralised distribution. In this region, recycled water
will be utilised for toilet flushing, outdoor watering, external maintenance (i.e. washing cars,
fountains) and fire fighting but is not permitted for the filling of pools or spas (Gold Coast
Water, 2004).
Currently recycled water is not flowing through the in-ground infrastructure; instead potable
water is supplying both lines for approximately 3832 homes. Being potable, this water is the
same quality, same cost and has the same level of restrictions as other potable water and at the
time of data collection, the campaign promoting the supply and encouragement of use of
recycled water had not yet been launched. In the future, the recycled water will be a low cost
and high quality Class A+5 supply. In 2004, Gold Coast Water (2004) originally estimated that
between 35-45% of total household water consumption can be replaced by recycled water, it
should be noted that total residential consumption was also higher than current consumption
rates, hence 35% was the revised estimate. The use of recycled water will reduce the demand on
current potable water supplies, decrease the volume of treated wastewater being released to the
environment and promotes the utilisation and reuse of a valuable resource (Gold Coast Water,
2004).
Recycled water will be supplied to residents in the PC region by the end of 2009. It is envisaged
that the recycled water uptake will be on par with initial targets. However, actual uptake and use
of recycled water especially for outdoor use can vary depending on restriction levels, social
values, climate, price of recycled water, land size, garden area and household perceptions and
attitudes towards water conservation (Syme et al., 2004; Dolnicar and Schafer, 2006)
This paper presents an investigation undertaken to examine the pre-commissioning level of both
the potable and recycled water use in PC and to predict future consumption levels once the
recycled water system has been commissioned. A discussion on the greater PC Dual
Reticulation End Use Study and objectives of this first phase of the research is presented below.
5 Class A+ recycled water is the highest quality of recycled water for non-drinking purposes in Queensland. Full details of
water quality guidelines for Class A+ and other recycled water schemes are published by the Department of Environment and
Resource Management (DERM) in the Water Quality Guidelines for Recycled Water Schemes and can be viewed at:
http://www.derm.qld.gov.au/water/regulation/recycling/pdf/water_quality_guidelines.pdf Standards of quality for Class A+
recycled water can also be viewed in Section 18AE, Schedule 3C of the Public Health Regulation 2005:
http://www.legislation.qld.gov.au/LEGISLTN/CURRENT/P/PubHealR05.pdf
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9.4 Pimpama-Coomera Dual Reticulation End Use Study
The PC Dual Reticulation End Use Study is a key component of the Gold Coast Watersaver End
Use Project. The objectives of the study are as follows:
Determine the recycled water pre-commissioning end uses for a statistically significant
sample of PC households;
Survey households participating in the end use study to determine attitudes, preferences
and behaviours with respect to recycled water; and
Predict the uptake of recycled water end uses and compare against actual end use break
downs post-commissioning.
This paper presents the results from Phase 1 of this study which includes: (1) the pre-
commissioning end uses for the sampled households; (2) create an end use adjustment
possibility distribution for each of the factors influencing the uptake of recycled water for
irrigation/outdoor purposes; and (3) the formulation of a post-commissioning prediction on end
uses within both the potable and recycled lines, with a particular focus on the estimated uptake
of recycled water for irrigation purposes. To achieve an accurate prediction on future recycled
water uptake, a range of information was analysed including both bulk and end use water
consumption levels, questionnaire surveys on water source preferences, and prior literature on
recycled water schemes, to name a few.
The approach taken to achieve the stated objectives for Phase 1 of the study was as follows:
1. Recruit a statistically significant sample of households (n=113) from the PC region and
undertake meter replacement to high resolution meters (Actaris CTS-5) to both the
potable and recycled lines to the household, which are capable of projecting 72.5 pulses
per litre;
2. Recruit a single reticulated control group (n=38) from a suburb with similar
demographics and volumetric consumption to PC and install high resolution meters;
3. Install data loggers (DataCell D-CZ21020) to record from both the potable and recycled
lines at the 10 second intervals necessary for end use analysis;
4. Undertake household stock inventory water audits with each household in the sample to
solicit demographics, a record of the water using fixtures and fittings within each home
(stock survey) and to establish unique water use behaviours of all residents within each
household i.e. approximate day/time and duration of water use activities such as
showers, baths, clothes washing, irrigation, etc. Stock inventory data cross referenced
with water audit stock survey data provided by the Australian Government Water
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Efficiency and Labelling Standards (WELS)6 Scheme database to obtain water use
consumption rates for fixtures such as washing machines, dishwashers, shower roses
and taps;
5. Conduct questionnaire survey with households to obtain detailed descriptive
information such as household resident age, family income, education level, etc.
Moreover, a range of questions sought to determine their likely uptake of recycled water
and their preference for predominant water sources available post-commissioning of
recycled water (i.e. potable, rain water tank, recycled water);
6. Conduct end use analysis graphically using Aquacraft’s Trace Wizard© software. A
quality assurance process to ensure accurate end use pattern matching was followed,
which included the following aspects: (a) utilising stock survey data, water use
behaviour survey data and household descriptive data to develop a unique template for
each household; (b) manual review and checking of each end use event over the two
week period by the analyst; and (c) independent checking of the categorised end use
data by a senior analyst. These steps provided the research team with greater confidence
in end use output files used for subsequent data analysis and results;
7. Compile end use water consumption summary for each household which serves as the
pre-commissioning end use data set; and
8. Utilise recycled water pre-commissioning end use data and baseline/end use adjustment
factor possibility distributions to make a prediction on the most likely recycled water
end use levels.
The pre-commissioning end uses and predicted post-commissioning end uses will serve as a
baseline against which actual post-commissioning water end use data can be compared.
9.5 Baseline Situation: Recycled Water Pre-Commissioning End Uses
Summaries of billed residential water meter consumption were obtained to establish average
potable consumption in single reticulated households on the Gold Coast and average potable
and recycled water consumption in the dual reticulated households in the PC region. The data
indicated that PC residents are currently consuming approximately 15% less total water than
other residents in the Gold Coast. This has not been the case in other dual reticulated regions
with Rouse Hill residents on average consuming 11% more water (potable and recycled) than
other Sydney residents when recycled water was being supplied to the region (Kidson et al.,
2006). Water consumption from the recycled water line currently accounts for 20% of PC
residents total water consumption. When comparing just potable water consumption, PC
6 WELS Scheme database available at: http://www.environment.gov.au/wels_public/
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residents are actually consuming 32% less than other Gold Coast residents. Rouse Hill
residents’ potable water consumption is 28% less than those in Sydney (Kidson et al., 2006).
To aid in the later provided prediction of potable and recycled water consumption within this
region, an understanding of where recycled water is used within the property is required.
Determining the percentage or volume of water use for toilet and irrigation requires examination
at the end use water consumption level (Turner, 2005). End use water consumption data was
obtained from a total of 113 dual reticulated households in the PC region and a control group of
38 single reticulated households in a comparable suburb on the Gold Coast. Figure 9-1 and
Figure 9-2 detail the end use break down in the single reticulated control group households, and
dual reticulated PC households, respectively.
Figure 9-1 and Figure 9-2 demonstrate that the uptake of water from the recycled water line in
PC is currently 20% of total water consumption for the monitored households (toilet and
irrigation recycled) which is also supported by bulk water meter readings. As noted, recycled
water is not currently supplied through the recycled water pipes; potable water is the current
source. Use of water for flushing toilets should not change when the recycled water is flowing
as lower cost or minimal restrictions should not alter the behaviour of toilet flushing. Figure 9-1
and Figure 9-2 also demonstrate that toilet volumes and percentages are similar between the PC
region and control group. The end use which will alter when recycled water is online will be
irrigation or outdoor use. Currently PC residents only use 6% of their total water consumption
from the recycled water line for outdoor uses (see Table 9-2). Even when considering that a
proportion (i.e. 50%) of the outdoor potable tap fixture use (10 litres per person per day
(L/p/day) or 6%) will transfer to recycled water the total irrigation volume still only amounts to
Figure 9-2 Dual reticulated (n=113) Gold Coast end use water consumption break
down (winter 2008)
Figure 9-1 Single reticulated (n=38) Gold Coast end use water consumption break
down (winter 2008)
Clothes Washer
26.8 L/p/d17.5%
Shower55.4 L/p/d
36.2%
Tap30.1 L/p/d
19.6%
Dishwasher1.8 L/p/d
1.2%
Bathtub3.2 L/p/d
2.1%
Toilet (Pot)19.3 L/p/d
12.6%
Irrigation (Pot)13.9 L/p/d
9.1%
Leak (Pot)2.7 L/p/d
1.8%
Average Daily Per Capita Consumption (L/p/day): Single Reticulation (n=38)
Clothes Washer
31.1 L/p/d19.6%
Shower47.7 L/p/d
30.1%Tap
26.0 L/p/d16.4%
Dishwasher2.4 L/p/d
1.5%
Bathtub7.6 L/p/d
4.8%
Toilet (Rec)21.7 L/p/d
13.7%
Irrigation (Pot)10.0 L/p/d
6.3%
Irrigation (Rec)10.2 L/p/d
6.4%
Leak (Pot)1.2 L/p/d
0.7%
Leak (Rec)0.7 L/p/d
0.4%
Average Daily Per Capita Consumption (L/p/day): Dual Reticulation (n=113)
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9.6% of total consumption (23.7% total). When the recycled water line is commissioned, it is
expected that this percentage will increase significantly from its current level. The following
section details the approach taken to approximate dual reticulation end uses; focused on the
uptake of recycled water for outdoor uses such as irrigation.
9.6 Predicting Recycled Water Post-commissioning End Uses
9.6.1 Predictive analysis approach and input factors
The majority of end uses established in the pre-commissioning data read conducted in winter of
2008 should remain constant. This includes toilet use, which is supplied by recycled water, as
this is not a discretionary use and will only be marginally if at all affected by the introduction of
recycled water. Therefore the predictive analysis conducted herein is focused on outdoor uses,
specifically the uptake of recycled water for irrigation and other outdoor purposes. To assist
with the prediction on outdoor use changes due to the commissioning of the recycled water line
in the region in mid 2009, the following factors have been considered:
Baseline end uses established from winter 2008 logging period and initial adjustments;
Predicted and actual recycled water use in other dual reticulated regions;
End use studies conducted elsewhere and irrigations’ contribution to total consumption;
Influence of restrictions on outdoor water use and changes to behavioural norms;
Outdoor water use activities source preference matrix created from survey responses
received by sampled households;
Influence of recycled water pricing;
Influence of climate, lot size and recycled water marketing campaign; and
Other factors affecting general outdoor use and uptake of recycled water.
The influences of these factors are discussed below as well as predicted post-commissioning
end uses.
9.6.2 Establishing baseline end use situational context
Table 9-2 displays the water end use percentage break down and relevant volumetric
consumption for residents in the PC region. A minor adjustment to this original end use break
down has been made, with 50% of potable irrigation water use being transferred to recycled
irrigation (Table 9-2). The lower cost of the recycled water and the encouragement to utilise this
cheaper and sustainable supply source will instigate this change. Some potable irrigation will
still occur for the filling of pools and spas.
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Table 9-2 assumes no increase in overall water consumption or change in behaviour. In fact,
prior research has established that indoor water consumption is not generally affected by
weather conditions (Gato, 2006). This has lead to researchers deducting winter use from
summer use to determine outdoor seasonal uses (Kidson et al., 2006). Hence, it is reasonable to
assume that indoor consumption in PC will remain relatively similar and the adjustments should
be made to irrigation.
With the transfer of half of the potable irrigation to the recycled water supply, Table 9-2 shows
that baseline recycled water consumption will increase from 20.6% to 23.7%. Leakage for the
recycled water supply has been retained at current levels as almost all leakage, as identified
graphically in the trace analysis, in the recycled water line is related with toilet refill. It should
be noted that other small volumes of leakage are also present within potable household
consumption from taps, showers and other devices as demonstrated in Figure 9-1 and Figure
9-2.
Table 9-2 PC baseline end use situational context
End Uses Volume (L/p/day) Percent (%) Potable End Uses Leak 1.2 0.8% Clothes Washer 31.1 19.6% Shower 47.7 30.1% Tap 26 16.4% Dishwasher 2.4 1.5% Bath 7.6 4.8% Irrigation 5.0 3.2%
TOTAL POTABLE 121 76.3% Recycled End Uses Leak 0.7 0.4% Toilet 21.7 13.7% Irrigation 15.2 9.6%
TOTAL RECYCLED 37.6 23.7% TOTAL VOLUME 158.6 100%
9.6.3 Influence of irrigation end use measurements conducted elsewhere
Loh and Coghlan (2003) in Perth found that irrigation can account for up to 54% or 180 L/p/d of
total end use while Roberts (2005) in Melbourne recorded up to 25% of total consumption or
57.5 L/p/d being outdoors. Heinrich (2007) in New Zealand recorded 22% or 44.2 L/p/d of
external use in summer and in winter on the Gold Coast the average outdoor consumption was
just 12% or 18.6 L/p/d. This figure is low as data was recorded during winter and over the
logging period unseasonably high rainfall occurred. Maidment et al. (1985) has previously
determined that rainfall can instigate a sudden drop in seasonal use. The Perth study was
conducted in early 2000 when domestic water was not generally valued in Australia. The 2005
Melbourne study of 57.5 L/p/day or 25% is more reflective of average unrestricted irrigation
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use. Whilst this irrigation volume is much higher than the current average consumption on the
Gold Coast, it is expected that the supply of discounted and minimally restricted recycled water
could potentially boost use to similar levels found in Melbourne.
9.6.4 Influence of water restriction levels and changes
Gato (2006, pp 112) established that with the absence of garden watering, brought on by the
implementation of outdoor water restrictions, Melbourne’s average winter consumption was
‘34% lower (758 against 503 L/household/d) than the summer consumption of the same year
(2004)’ while the ‘per capita consumption incurred a reduction of 35% (260 verse 168 L/p/d)’.
Investigations were undertaken to establish the impact of outdoor water restrictions on the Gold
Coast (see Table 9-3).
Table 9-3 Influence of water restriction levels on billed water meter consumption in the Gold Coast
(ML/d)
Year
Population Growth (from Priority Infrastructure Plan estimates)
Level 1 Odd/Even days. Sprinkler & pool top up allowed
Level 2 Odd/Even days with sprinkler ban. Hose allowed
Level 3 Hose/sprinkler ban. Odd/Even bucket watering
Level 4 Odd/Even hand held buckets during designated time
Level 5 Odd/Even hand held buckets for garden during designated time only. Target 140L/p/d
Level 6 Level 5 & further business & high residential users targeted. Target 140L/p/d
0% 13% 14% 18% 24% 30% 2004/05 177.0 153.9 151.6 144.7 134.6 123.0 2005/06 2.24% 181.0 157.3 155.0 148.0 137.6 125.8 2006/07 3.07% 186.5 162.1 158.5 151.3 141.8 129.6 2007/08 3.07% 192.2 167.1 163.3 155.9 146.2 134.0 2008/09 3.07% 198.1 172.3 168.3 160.7 150.7 137.7 2009/10 3.07% 204.2 177.5 173.5 165.7 155.3 142.0 2010/11 3.07% 210.5 183.0 178.8 170.8 160.1 146.3
Table 9-3 demonstrates that water restrictions reduced potable water consumption in the Gold
Coast by as much as 30%. This figure is on-par with that reported in Melbourne.
Determining how residents’ behaviour will alter in PC when moving from five years under
varying levels of water restriction to basically non-restricted outdoor water use is difficult and
little research is available on the topic. It is assumed that behaviours will remain reasonably
constant with water consumption increasing over time to align with the permanent water
conservation targets stipulated in the South East Queensland Water Strategy (i.e. Target 200).
The fact that residents in Rouse Hill are consuming more water than residents in other regions
of Sydney (Kidson et al., 2006) supports the premise that outdoor consumption will increase
over time as has been the case in other dual reticulated regions.
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9.6.5 Influence of customer water source preferences
In determining which event water is used for externally, end use data is limited as it only
demonstrates the summation of all external use as one. Individual events can be seen in Trace
Wizard© but determining whether an event is watering the lawn or garden, or housing down the
driveway can not be done without the use of diaries. To obtain practical volumes of water used
for such outdoor purposes, a literature search as well as a questionnaire survey investigation was
carried out. Loh and Coghlan (2003) with the Water Corporation of Western Australia found
that the majority of outdoor water consumption was used on the lawn and garden with the
remaining volume used for filling swimming pools.
Prior research which focused on correlating total household water consumption with garden
based attitudes has resulted in inconsistent outcomes (Syme et al., 2004). Gato (2006, pp. 98)
established that in Melbourne, in February 2004, that the average volume of a garden watering
event was 202L (n=1468), with an average duration of 17 minutes and events occurred on
average 3 times a week. A quantitative attitudinal survey was undertaken to assist in
establishing which water source PC residents prefer to use for various high use outdoor
activities; the results are presented in Table 9-4. Respondents were requested to rank their
preferred water source, with 1 being the most preferred and 3 being the least preferred water
source (i.e. PW: Potable Water; RW: Recycled Water; and RWT: Rain Water Tank) for the
listed activities.
Table 9-4 PC respondent perceptions on preferred source for outdoor activities (n=70)
Activity Recycled Water
Rain Water Tank
Potable Water
Ranked Preference Percentage (%)
Watering the Pot Plants
2 1 3 RWT = 50.0%; RW = 40.0%; PW = 10.0%
Watering the Garden 2 1 3 RWT = 51.4%; RW = 45.7%; PW = 2.9%
Watering the Lawn 1 2 3 RW = 50.0%; RWT = 40.0%; PW = 5.7% Do not do = 4.3%
Cleaning Hard Surfaces
1 2 3 RW = 62.9%; RWT = 30%; PW = 2.8%; Do not do = 4.3%
Washing the Car 1 2 3 RW = 44.3%; RWT = 42.8%; PW = 10% Do not do = 2.9%
Washing the House 1 2 3 RW = 47.1%; RWT = 38.6%; PW = 8.6% Do not do = 5.7%
Table 9-4 shows that for the majority of outdoor high volume uses, PC residents would prefer to
use recycled water. Interestingly, respondent’s preferred rain water tanks for watering pot plants
and the garden. Although this is the case, only 21 of the 70 respondent households actually has a
rainwater tank on their property with the average size of a RWT in the dual reticulated region
being 3000L with only two of these RWTs plumbed into homes, one to a cold kitchen tap
(gravity fed) and the other for cold laundry use (pump fed). Hence a significant proportion of
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residents will in fact use recycled water as that is the only available water source alternative to
potable. Those with RWTs have the option of utilising either rain water or recycled water (RWT
is the preference for watering pot plants and the garden but not other outdoor uses such as
watering the lawn) although in dryer months, when irrigation demand is at its highest, these
small capacity RWTs are likely to have emptied and hence recycled water will need to be
utilised for all outdoor watering activities.
Customer surveys (n=70) also revealed that 62% of residents have stated they will increase their
recycled water consumption while 30.5% predict they will continue to use the same amount of
recycled water and 5.1% will reduce their recycled water use once recycled line water comes
online. For potable water consumption levels, 58% expect to use the same amount of water,
37% will reduce their water and 5% expect to increase their water consumption. For those
households with RWTs, 20.3% state they will reduce tank water consumption, 52.5% will use
the same amount of tank water and 27.2% expect to increase RWT use when recycled water
comes online. These perceived water source behaviour changes demonstrate a preference to
increase recycled water consumption, reduce or maintain potable water consumption, and to
reduce or maintain RWT consumption (72.8%), with only a quarter indicating they may
increase their RWT use if water is available.
9.6.6 Influence of recycled water pricing
Various opinions have been published on the effect of price on water consumption. While it was
initially thought that pricing water per unit, and hence payment for what water consumers use,
would be an effective demand management option (Inman and Jeffrey, 2006), research has
demonstrated that is only the case for some instances and in most cases water demand is price
inelastic (Espey et al., 1997; Renwick and Archibald, 1998). Thomas and Syme (1988) provided
evidence that external use was likely to be substantially more sensitive to price changes than
indoor use. Hence, external use may be one consumption use that possesses price elasticity
therefore the price of recycled water is likely to affect the consumption rate in PC. Hurlimann
(2008, pp. 4) reported that community members of Mawson Lakes have experienced a
‘significant increase in the perceived value of recycled water’ with 269 survey respondents
expressing that the cost of recycled water should increase to AUD$0.89/kL in 2007 in
comparison to AUD$0.49/kL in 2005 and AUD$0.46 in 2004. This demonstrates a willingness
to pay more for the product and recognition of its value. The cost of recycled water in the Gold
Coast was established through community consultation and market research undertaken by the
Gold Coast Waterfuture Product and Pricing Advisory Committee. The current cost, in the
09/10 financial year, is AUD$1.34/kL or 60% of the potable water price which is
AUD$2.24/kL. Recycled water is charged at a considerably lower rate than that of potable water
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and hence it is assumed that the use of recycled water rather than potable water outdoors will
occur.
9.6.7 Influence of climate
Hoffmann et al. (2006, pp. 347) has illustrated that there is a strong influence on residential
water consumption from the weather ‘particularly summer months and the number of rainy
days’. End use consumption data collected in the Gold Coast over a winter period with higher
than average rainfall very likely contributed to the low baseline value for irrigation related water
consumption. The uptake of recycled water in the Gold Coast will be intrinsically affected by
the climate with hot dry periods resulting in higher outdoor water consumption while cooler or
rain periods will reduce outdoor water consumption. Higher uptake rates will be experienced in
PC if drought conditions occur but if weather conditions of higher rainfall continue, as has been
seen over first part of 2009, outdoor water consumption may not increase substantially
immediately following commissioning.
9.6.8 Influence of lot size
Mayer and DeOreo (1999) established that in America larger lot sizes consumed more water
through irrigating although residential behaviour of watering lawns is quite predominant. In PC
it is assumed that lot size will have a slight effect on outdoor irrigation although it is believed
that garden size and plant type will have more impact that lot size. The average lot size in the
PC region is 662m2, maximum lot size is 15,000m2 and minimum size is 208m2.
9.6.9 Influence of recycled water awareness campaign
An awareness campaign will be launched to PC residents prior to recycled water coming online.
This campaign has the potential to affect the rate of uptake of recycled water in the region.
Generally public education or awareness is targeted to reduce water consumption and it has
been shown to be successful (Nieswaidomy, 1992). Encouraging the increase of recycled water
in the PC region will have varying outcomes on uptake volumes of the product. Similar
campaigns would have been launched in other dual reticulated regions although they have not
specifically been measured hence it is difficult to predict the impact of such a campaign. Overall
it is predicted that an awareness campaign will increase recycled water use in PC as residents
will understand that the product is available and is a cheaper source of water, thus leading to an
increase in consumption.
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9.7 Predicting Post-commissioning Dual Reticulation End Uses
9.7.1 Possibility theory underpinning prediction model
There are a number of mathematical techniques that are commonly applied for predictive
assessments, including probability theory, Monte Carlo simulation, sensitivity analysis and
possibility/fuzzy set theory. This study adopted the latter possibility/fuzzy set theory approach
due to the inherent fuzziness of future predictions of water use for a new supply source (i.e. A+
recycled water) in a new context (e.g. Gold Coast, Queensland, Australia). Probability theory is
not suitable for this application as it relies on historical data sets to accurately predict future
scenarios. Given that there are a limited number of dual reticulation water supply schemes in
Australia, limited availability of recycled water use in these existing communities, and that the
climatic conditions of each region has a significant bearing on recycled water take-up, this
intrinsic uncertainty does not fit the axiomatic basis of probability theory. This is simply due to
the uncertainty of recycled water uptake estimates being usually caused by the inherent
fuzziness of the parameter estimate rather than randomness (Choobineh and Behrens, 1992).
Similarly, Monte Carlo simulation and sensitivity analysis require historical data in the form of
probability distributions to provide meaningful predictions on future water use scenarios. A
technique to alleviate the shortcomings of these traditional techniques in this uncertain context
is to apply possibility theory where the user needs only to determine a range (lower and upper
least likely boundary) and most likely value for each parameter contributing to the estimate.
Practitioner and research literature was examined to create a range for each examined factor and
expert intuition was applied to ascertain the most likely value within that range. Therefore,
possibility theory is superior to other techniques where qualitative judgements dominate the
prediction process (Altunkaynak et al., 2005).
Another issue to address in the predictive assessment was the interdependent nature of
influencing factors and the relative contribution of each factor to the final estimate (see Table
5). Structural Equation Modelling (SEM) is the ideal technique that handles both the direct and
indirect effects of multiple factors on independent variables (Stewart, 2007). However, given
the lack of empirical data to build such a statistically powerful model, a more simplistic
weighted contribution assessment by an expert panel was employed. Nonetheless, this simple
weighted average model avoids double counting and ensures that those factors that were
perceived to have a greater influence on the final estimate contribute greater to the final
weighted average.
9.7.2 Prediction model application
As mentioned, any increase in recycled water consumption in PC is likely to occur through
irrigation use. Other end uses are likely to remain the same as the baseline end use measurement
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(see Table 9-2). Each of the above listed factors which are noted to potentially influence
recycled water utilisation for irrigation purposes (i.e. outdoor uses) have been allocated a lower
least likely, most likely and upper least likely possibility distribution established from the above
mentioned discussion (see Table 9-5). Factor A considers the percentage of recycled water use
in mature dual reticulation schemes removing 14% for toilet flushing. Factor B utilises the
lowest and highest irrigation percentages as found in other end use studies. Factor C was
established using Gold Coast Water (GCW) restriction data with a 30% increase with no
restrictions and 13% increase if restrictions on sprinklers were introduced. Factor D utilises
survey data on customer water source preferences received from PC residents participating in
the end use study. Factor E presents the influence of the potable comparative price of recycled
water. Factor F was established by considering low to extreme irrigation events during summer
months. Finally, Factor G conservatively estimates the influence of the awareness campaign on
uptake.
The values serve as an adjustment to the baseline measured end use irrigation volume or total
consumption level on a litre per person per day (L/p/day) basis. Influence factor weightings
were determined by an expert panel. The weighted summation of the adjusted baseline value
resulted in a possibility distribution for recycled water irrigation as: (1) lower least likely value
= 25.6L/p/day; (2) most likely value = 30.6L/p/day; and (3) upper least likely value =
41.8L/p/day.
Table 9-5 Recycled water for irrigation purposes influencing factors and weighted possibility distribution
Factor ID (i)
Influencing Factor Description
Adjustment Method Lower Value
Most Likely Value
Upper Value
Influence Weight (wi)
A Other dual reticulated recycled water uptakes
% of total end use1 21% 26% 36% 25%
B Prior end use irrigation break down
% of total end use1 22% 30% 54% 15%
C Relaxed water restrictions
% increase on baseline2 13% 20% 30% 10%
D Customer water source preferences
% increase on baseline2 30% 40% 50% 15%
E Price of recycled water % increase on baseline2 20% 30% 40% 15% F Climate affects % increase on baseline2 20% 30% 40% 10% G Awareness campaign % increase on baseline2 20% 25% 30% 10%
Notes: 1Total volumetric consumption = 170L/p/day; 2Baseline recycled water irrigation established as 15.2L/p/day
As per Table 9-6, the most likely recycled water uptake for irrigation in PC is estimated to be
30.6 L/p/d thereby resulting in total recycled water use (i.e. toilets, irrigation and leakage)
equating to 30.5%. The predicted increase in recycled water consumption takes the current total
per capita consumption from 158.6 to 174 L/p/day. Lower and upper estimates result in recycled
water utilisation being 28.4% and 34.7% of total water consumption on a per capita basis,
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respectively. Establishment of actual recycled water end uses will be established in the second
phase of the PC dual reticulated end use study.
Table 9-6 PC recycled water post-commissioning end use prediction
End Use Break Down Most Likely End Uses Lower End Uses Upper End Uses
End Uses Volume
(L/p/day) Percent
(%) Volume
(L/p/day) Percent
(%) Volume
(L/p/day) Percent
(%) Potable End Uses
Leak 1.2 0.7% 1.2 0.7% 1.2 0.6% Clothes Washer 31.1 17.9% 31.1 18.4% 31.1 16.8% Shower 47.7 27.4% 47.7 28.2% 47.7 25.8% Tap 26 14.9% 26 15.4% 26 14.0% Dishwasher 2.4 1.4% 2.4 1.4% 2.4 1.3% Bath 7.6 4.4% 7.6 4.5% 7.6 4.1% Irrigation 5.0 2.9% 5.0 3.0% 5.0 2.7%
TOTAL POTABLE 121 69.5% 121 71.6% 121 65.3% Recycled End Uses Leak 0.7 0.4% 0.7 0.4% 0.7 0.4% Toilet 21.7 12.5% 21.7 12.8% 21.7 11.7% Irrigation 30.6 17.6% 25.6 15.1% 41.8 22.6% TOTAL RECYCLED 53 30.5% 48 28.4% 64.2 34.7%
TOTAL VOLUME 174 100% 169 100% 185.2 100%
9.8 Future Research: Post-commissioning Comparative Analysis
The end use predictions determined in this Phase will be assessed in Phase 2 of the PC Dual
Reticulated End Use Study. Phase 2 of the research involves the collection of end use water
consumption data in summer (December 2009 to February 2010) after recycled water is
supplied to PC. The collection and analysis of recycled water end use data will allow actual
quantification of recycled water consumption in PC. Real consumption data will be compared
with the predicted uptake presented in this paper.
9.9 Conclusion
Several dual reticulated schemes are online in Australia with recycled water uptake rates
between 35-50% recorded. The PCWF Master Plan predicted that 35-45% of total water
consumption in the PC dual reticulated region will be recycled water. Billing data determined
that PC residents are currently consuming 20% of their total water through the recycled water
meter (potable water being the current source) and end use investigations determined that in
winter 2008, 14% of that use is occurring through toilet flushing while only 6% is being used
externally as irrigation. Expectedly, current consumption is currently 15% lower than the initial
minimum targets. Recycled water outdoor events will, over time, meet or exceed the current
shortfall. Exploration into residential water restrictions on the Gold Coast revealed that full
outdoor water restrictions (Level 6) lead to a 30% reduction in total water consumption.
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Questionnaire surveys of PC residents (n=70) determined that recycled water was the preferred
source for most outdoor activities and 62% of those respondents believed that they would
increase their recycled water use once it was online. The effect of these influencing factors
along with climate, pricing, the awareness campaign and the change from restricted to un-
restricted use for recycled water and their potential influence on the actual uptake of recycled
water were encapsulated in a predictive model. This model resulted in a most likely prediction
that recycled water uptake will increase to around 30% in the PC region within the first year.
GCW will continue investigating the actual uptake of recycled water in the PC region through
Phase 2 of the PC Dual Reticulated End Use Study.
9.10 References
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Anderson, J. (2003) The environmental benefits of water recycling and reuse. Water Science and Technology: Water Supply, Vol 3:4, pp. 1-10.
Anderson, J. M. (1996) The potential for water recycling in Australia: Expanding our horizons. Desalination, Vol 106:1-3, pp. 151-156.
Baldwin, C. (2008) Aurora: A Case Study. Your Development Webpage, online article, available at: http://yourdevelopment.org/casestudy/view/id/13.
Bhatti, M. (1999) The meanings of gardens in an age of risk. In: T. Chapman, J. Hocky (Eds), Ideal Homes? Social Change and Domestic Life. Routledge, London, pp. 181-193.
Bhatti, M. & Church, A. (2000) I never promised you a rose garden: gender, leisure and home-making. Leisure Studies, 19: 183-197.
Choobineh, F. & Behrens, A. (1992) Use of interval mathematics and possibility distribution in economic analysis. Journal of Operational Research Society, 43(9): 907-918.
Council of Australian Governments (COAG) (2009) Intergovernmental Agreement on a National Water Initiative. Canberra. Online article, accessed 23/03/09, available at: http://www.coag.gov.au/coag_meeting_outcomes/2004-06-25/index.cfm.
Dolnicar, S. & Schafer, A. (2006) Public perception of desalinated versus recycled water in Australia. AWWA Desalination Symposium 2006. Australia, University of Wollongong.
Espey, M., Espey, J. & Shaw, W. D. (1997) Price elasticity of residential demand for water: A meta-analysis. Water Resources Res, Vol 33, pp. 1369-1374.
Fearnley, E. J., Thomas, K. D., Luscombe, A. & Cromar, N. (2004) Determination of water usage rates and water usage patterns in residential recycling initiative in South Australia. Environmental Health, Vol 4:2, pp. 72-81.
Gato, S. (2006) Forecasting Urban Residential Water Demand. School of Civil, Environmental and Chemical Engineering. RMIT, Melbourne.
Gold Coast Water (2004) Pimpama Coomera Waterfuture Master Plan March 2004. Gold Coast, Gold Coast Water and Gold Coast City Council.
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Heinrich, M. (2007) Water End Use and Efficiency Project (WEEP) - Final Report. BRANZ Study Report 159. Judgeford, New Zealand, Branz.
Hoffmann, M., Worthington, A. & Higgs, H. (2006) Urban water demand with fixed volumetric charging in a large municipality: the case of Brisbane, Australia. The Australian Journal of Agricultural and Resource Economics, Vol:50, pp. 347-359.
Hurlimann, A. & McKay, J. (2006a) Urban Australians using recycled water for domestic non-potable use—An evaluation of the attributes price, saltiness, colour and odour using conjoint analysis. Journal of Environmental Management, Vol: 83, pp. 93-104.
Hurlimann, A. C. (2008) Community Attitudes to Recycled Water Use: an Urban Australian Case Study Part 2. Salisbury, SA, CRC for Water Quality and Treatment Project No. 201307.
Hurlimann, A. C. & McKay, J. M. (2006b) What attributes of recycled water make it fit for residential purposes? The Mawson Lakes experience. Desalination, Vol 187:1-3, pp. 167-177.
Inman, D. & Jeffrey, P. (2006) A review of residential water conservation tool performance and influences on implementation effectiveness. Urban Water Journal, Vol 3:3, pp. 127-143.
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Kidson, R., Spaninks, F. & Wang, Y.-c. (2006) Evaluation of water saving options: Examples from Sydney Water’s demand management programs. Water Efficiency 2006, Australian Water Association, Ballarat, 13 October 2006.
Loh, M. & Coghlan, P. (2003) Domestic Water Use Study. Perth, Water Corporation.
Maidment, D. R., Miaou, S. P. & Crawford, M. M. (1985) Transfer Function Models of Daily Urban Water Use. Water Resources Research, 21(4): 425-432. Apr. 1985a.
Marks, J. S. & Zadoroznyj, M. (2005) Managing Sustainable Urban Water Reuse: Structural Context and Cultures of Trust. Society & Natural Resources, Vol 18:6, pp. 557-572.
Mayer, P. W. & DeOreo, W. B. (1999) Residential End Uses of Water. Aquacraft, Inc. Water Engineering and Management, Boulder, CO.
Nancarrow, B. E., Kaercher, J. D. & Po, M. (2002) Community Attitudes to Water Restrictions Policies and Alternative Sources: A Longitudinal Analysis 1988-2002. Australian Research Centre for Water in Society, CSIRO.
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Po, M., Nancarrow, B. E., Leviston, Z., Porter, N. B., Syme, G. J. & Kaercher, J. D. (2005) Predicting Community Behaviour in Relation to Wastewater Reuse. CSIRO, Canberra.
Renwick, M. A. & Archibald, S. O. (1998) Demand-side management policies for residential water use: who bares the conservation burden? Land Economic, Vol 74, pp. 343-359.
Roberts, P. (2005) Yarra Valley Water 2004 Residential End Use Measurement Study. Melbourne, Yarra Valley Water.
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Sime, J. (1993) What makes a house a home: the garden? In: Bulos, M, Teymur, N (Eds), Housing: Design, Research, Education. Aldershot, Averbury, pp. 239-254.
Stewart, R. A. (2007) IT enhanced project information management in construction: pathways to improved performance and strategic competitiveness. Automation in Construction, 16: 511-517.
Sydney Water (2008) Recycled water in the Rouse Hill area - saving drinking water for drinking. Online article, accessed 10/03/08. Available at: http://www.sydneywater.com.au/Publications/FactSheets/FINAL_Rouse_Hill_Brochure_Feb_08.pdf#Page=1.
Syme, G. J., Shao, Q., Po, M. & Campbell, E. (2004) Predicting and understanding home garden water use. Journal of Landscape and Urban Planning, Vol 68, pp. 121-128.
Thomas, J. F. & Syme, G. J. (1988) Estimating residential price elasticity for water in the presence of private substitutes: a contingent valuation. Water Resources Research, Vol 24, pp. 1847-1857.
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White, S. & Turner, A. (2003) The role of effluent reuse in sustainable urban water systems: untapped opportunities. National Water Recycling in Australia Conference. Brisbane, September 2003.
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Chapter 10
Residential potable and recycled water end uses in a dual reticulated supply system
This chapter is a reformatted version of a peer-reviewed article by the author published in the
Journal of Desalination (2011): Vol 272:1-3, pp. 201-211, DOI: 10.1016/j.desal.2011.01.022.
10.1 Abstract
The need to understand, model and predict urban water consumption is paramount, particularly
with urban densities increasing throughout the world. Specifically, it is vital to determine
potable water savings, daily demand patterns and actual end use water consumption experienced
in diversified water supply schemes in order to verify planning estimates and justify the future
application of such schemes. This paper details the results of a mixed methods (quantitative and
qualitative) end use investigation, pre- and post-commissioning of recycled water, in a dual
reticulated supply scheme in the master planned Pimpama Coomera region, Gold Coast,
Australia. Recycled water, supplied for irrigation and toilet flushing, accounted for 59.1 L/p/d or
32.2% of total consumption post-commissioning, with irrigation being 28.9 L/p/d or 15.7%.
Furthermore, developed end use diurnal patterns demonstrate the unique daily demand
consumption within the region and significant reductions in peak potable water demand when
compared with single reticulated supply areas. The paper concludes with discussions of
implications for better informed water services infrastructure planning activities.
10.2 Integrated Urban Water Resources Management
The provision of a secure supply of water for increasing populations in climate challenged
regions is a critical issue. Australia is the world’s driest inhabited continent with unpredictable
rainfall patterns, hence the significant focus on conserving and sustainably managing the
nation’s already finite water supplies (Birrell et al., 2005; Commonwealth of Australia, 2008c).
Queensland, an eastern state of Australia, has become increasingly hotter and drier, with trends
indicating reduced rainfall of up to 50mm annually (Anderson, 1996; Commonwealth of
Australia, 2010). This reduced rainfall trend is occurring over concentrated urban centres, where
much of the nation’s population resides, resulting in rainfall-dependent eastern Australian cities
and towns having water supplies fall to record low levels over the past ten years
(Commonwealth of Australia, 2008a; ABS, 2010). Traditionally, the supply of water for cities
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and towns placed a heavy reliance on dams, weirs or rivers but changing weather patterns and
the growing urban population’s water demands have necessitated a new approach (Barlow,
2009). Hence, Australia is now focussed on the development, planning and implementation of
new water demand reduction initiatives to meet short-term water supply deficiencies and to
manage long-term demand, together with supply augmentations including desalination (Turner
et al., 2005; Webb, 2007; Barlow, 2009).
Integrated sustainable water resources planning and management has become a key driver of a
raft of measures required to ensure future water demands are satisfied (WSAA, 2008). This
sustainable water resources planning and management method involves the introduction and
application of alternate supply options (such as desalination or recycling), water demand
management measures (efficient devices, water restrictions and price controls) and source
substitution initiatives (rainwater tanks, stormwater or recycled water), for a sustainable and
secure source of water for future populations (Mitchell, 2006). The application of demand
management and source substitution initiatives is widespread throughout the nation. However,
the effective potable end use water savings which can be achieved by these measures is assumed
or predicted and in almost all cases, and often remains unverified after application (Turner and
White, 2006; Turner et al., 2007b). The verification of effective water savings related to such
initiatives is vital for the improvement of water services planning; for the accurate forecasting of
water supply and demand and for strengthening the knowledge and application of such
sustainable water management initiatives for the future (WSAA, 2003; WSAA, 2008).
10.2.1 Water services planning
Urban water demand forecasting used for the planning of water services infrastructure has been
carried out for decades with consistent improvement occurring with the invention of new data
collection techniques, analysis and modelling technologies. Predicting urban water demand
requires an understanding of historical water services records, projected changes in demand
patterns and system performance (DNRM, 2005). Water demand modelling elements, as
detailed by WSAA (2003), include diurnal patterns, end use water consumption, peaking factors
(maximum day, mean day maximum month and maximum hour), fire fighting parameters,
system losses, non-revenue water and pressure parameters. These and other climatic,
demographic and consumer influences are detailed in Figure 10-1. Figure 10-1 illustrates the
influence of climate, water usage practices, water use equipment, demographics and land use,
the water supply system and source substitution on water demand. While all elements presented
in Figure A.1 are required for urban water forecasting, it is well documented that all too often
‘demand forecasting studies have relied on projections of historical metered data without
considering end uses’ or by adopting end use data from different locations or countries (WSAA,
2003, pp. 6). Because household water consumption differs between countries, locations and
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populations, it is paramount that location specific end use data is utilised for local demand
forecasting (Turner et al., 2005; Inman and Jeffrey, 2006).
Figure 10-1 Factors that influence demand (White and Turner (2003) & WSAA (2008))
Giurco et al. (2008a) state that end use water consumption data is also required for the
determination of actual potable water savings of alternative supply sources and water demand
management initiatives. End use data assists in refining and validating the design assumption
parameters that influence the planning of water services infrastructure (Gato, 2006). The advent
of high resolution water meters and loggers along with affordable wireless communication
technologies has enabled the dynamic, accurate measurement and data transfer of end use water
consumption information (Stewart et al., 2010).
10.2.2 Water end use and diurnal patterns
Water end use studies provide data to assist in the determination of when, where and how
residents consume water in the home (White, 2001; Giurco et al., 2008a). End use studies also
offer ‘significant opportunities for providers to improve water service delivery and long term
planning’ through the provision of detailed consumption data utilised for water demand
predictions (Giurco et al., 2008a, pp. 1). The collection of end use data also assists with
verification of other demand forecast factors including diurnal patterns and peaking factors like
maximum day, mean day maximum month and maximum hour. Diurnal patterns demonstrate
the demand or consumption across a day in hourly intervals. This pattern varies depending on
the population, weather, the time of year, the day of the week (i.e. weekday versus weekends),
season and residential consumption characteristics (Zhou et al., 2002). In Australia, end use
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water consumption studies have been undertaken in Perth and Melbourne, and most recently,
the herein described investigation on the Gold Coast. Studies have been done in the USA and
New Zealand. In Queensland, numerous bulk supplied diurnal patterns have been determined
for forecasting total residential urban water use. However, end use water consumption and end
use diurnal patterns for Queensland and for the Gold Coast are not available. Table 10-1 details
some of the more significant end use studies completed.
Table 10-1 Summary of findings from other water end use studies
Author Study title Country Region No. homes
Avg. consumption (L/p/day)
End use or additional factors investigated
Willis et al. (2009b)
Gold Coast Watersaver End Use Study
Australia Gold Coast 151 Winter: Indoor = 138.6 Outdoor = 18.6
End use only to date
Mead (2008)
Investigation of Domestic End Use
Australia Toowoomba 10 Indoor & outdoor = 122
End use & diurnal patterns
Heinrich (2007)
Water End Use and Efficiency Project (WEEP)
New Zealand
Kapiti Coast 12 Indoor & outdoor = 184.2 Summer: 203.9 Winter: 168.1
End use & bulk diurnal patterns
Roberts (2005)
REUMS Australia Yarra Valley, Melbourne
100 Indoor = 169 Outdoor = extra 20% = 34
End use & diurnal patterns
Mayer et al. (2004)
Tampa Water Department Residential Water Conservation Study
United States of America
Tampa 26 Pre retrofit = 752.9 Post retrofit = 403.9 (indoor & outdoor)
End use and retrofitting
Loh and Coghlan (2003)
Domestic Water Use Study
Australia Perth 124 & 120
Indoor = 155 Outdoor = extra 54% = 83.7
End use & bulk diurnal patterns
AWWA (1999)
Residential End Uses of Water (REUW)
United States of America
12 regions 1188 Indoor = 262.3 Indoor & outdoor = 650.3
End use & diurnal patterns
Loh and Coghlan (2003) undertook the first national end use investigation in Perth, Australia
which detailed diurnal patterns from a total consumption level based on income, no end use
diurnal patterns were published. The variability between indoor and outdoor consumption
recorded in earlier end use studies is particularly prevalent when comparing Perth and
Toowoomba (Table 10-1). Outdoor consumption in Australian studies ranged from 18.6 litres
per person per day (L/p/d) in winter in the Gold Coast, 34 L/p/d Melbourne and 83.7 L/p/d in
Perth. Indoor consumption also varied, with the Perth study recording 155 L/p/d, the Melbourne
study 169 L/p/d, the Gold Coast study 138.6 L/p/d and the Toowoomba study recording just 122
L/p/d. Roberts (2005) end use investigation covering Yarra Valley in Melbourne also detailed
end use water consumption diurnal patterns for winter and summer use. In Roberts (2005)
winter study, end usage peaked between 7 and 8am (9.1% of total use), mostly due to
showering, and between 6 to 7pm (6.9% of total use) due to a range of end uses in the home.
Summer morning end use peaked between 7 and 8 am (8.3% of total use) while the evening
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peak occurred between to 9 to 10pm (10.3% of total use) due to significant irrigation usage
(Roberts, 2005). While Mead’s (2008) Toowoomba end use study was only from a small
sample, end use diurnal patterns were detailed. Mead’s (2008) highest peak occurred between 7
to 8am in the morning at 38 litres per household per day (L/H/d) with the evening peak
occurring between 5 to 6 pm (32 L/H/d). Shower usage was the highest end use contributor in
both morning and evening peaks. Weekend data showed flatter and longer peak periods in the
morning, with similar patterns for the evening. Clothes washing was an influential end use
peaking factor on the weekends (Mead, 2008). The variability described between indoor,
outdoor and diurnal consumption patterns determined through earlier end use studies prompted
Giurco (2008a) and WSAA (2003) to encourage more research in this field. End use
investigations into the effective water savings attributed to demand management and source
substitution initiatives are required (Giurco et al., 2008b; WSAA, 2008).
The use of recycled water for specified end uses is well accepted as an effective and sustainable
measure of water conservation and other schemes have been implemented throughout Australia
(Anderson, 1996; Marks and Zadoroznyj, 2005; Po et al., 2005). The six schemes currently
present throughout the nation include Rouse Hill (Sydney), Mawson Lakes (Adelaide), New
Haven Village (Adelaide), Aurora (Melbourne), Marriott Waters (Melbourne) and the herein
described Pimpama Coomera scheme (Gold Coast) (Willis et al., 2010a). All these schemes
supply recycled water for toilet flushing and irrigation. These schemes were all premised on
modelled predictions of end use and total potable water savings which could result from the
application of dual reticulated recycled water. Predicted water savings ranged from 30–50% of
the households’ total demand (Fearnley et al., 2004; Hurlimann and McKay, 2006a). Bulk
supplied data have been recorded at Rouse Hill and New Haven Village with savings between
35–50% found respectively (Fearnley et al., 2004; Sydney Water, 2008). Actual potable water
savings for the other dual reticulated schemes are yet to be published. To date, no data have
been published internationally on the actual water end use sourced from domestic potable and
recycled service pipes within dual reticulated regions, nor has there been any verification of
modelled end use diurnal demand patterns for these unique supply areas. Such field-collected
end use data are necessary to improve forecasting, water services planning and to strengthen the
application of similar schemes.
10.2.3 Gold Coast’s Pimpama Coomera dual reticulation scheme
Gold Coast City is one of South East Queensland’s major urban growth areas with the
population predicted to grow from the current 0.5 million to 2.5 million people by 2056 (Po et
al., 2005). This population expansion would trigger water consumption increases from the 2007
consumption of 185 megalitres per day (ML/d) (≈ 48.87 mega gallons (US) per day) to 466
ML/d by 2056 (≈ 123.1 mega gallons (US) per day) (GCW & GCCC, 2007). With residents
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consuming 75% of the city’s total yearly water supply in 2008/09, considerable focus has been
placed on reducing and managing residential water consumption in the city as well as
reclaiming water and sourcing through desalination (capacity of Tugun Desalination Plant 125
ML/d).
The PCWF Master Plan is the blueprint for sustainable integrated urban water management, for
the Pimpama Coomera region of the Gold Coast, which is largely undeveloped and one of the
fastest growing residential areas in Australia (Po et al., 2005). It stipulates the provision of
sustainable water sources for a projected 150,000 people in 2056 (Pimpama Coomera region
only) through the inclusion of dual reticulated recycled water, water conservation through water
demand management (WDM) measures, rainwater tanks, stormwater management and smart
sewers. The PCWF Master Plan region is Australia’s first centralised dual reticulation
distribution scheme for recycled water, providing Class A+ recycled water for approved end
uses, which include toilet flushing and external irrigation (with the exception of filling pools
and spas). Class A+ recycled water is the highest quality of recycled water for non-drinking
purposes in the State of Queensland, Australia. It was predicted that between 30 to 40% of
traditional communities’ existing consumption could be substituted by recycled water. The
introduction of rainwater tanks and water conservation measures would also reduce total potable
water consumed in the PCWF Master Plan region (GCW, 2004).
The Pimpama Coomera (PC) End Use Study is a component of the wider Gold Coast
Watersaver End Use (GCWSEU) Study which commenced in 2007 (Willis et al., 2009b). The
GCWSEU study was developed to investigate end use water consumption on the Gold Coast.
Other objectives include establishing the effective end use savings attributed to dual reticulation
and water demand management initiatives such as efficient and resource consumption
awareness devices (Willis et al., 2010b). To date, there have been no end use investigations on
dual reticulated recycled water schemes. Hence, the PC End Use Study was focused on
establishing the end use water consumption, pre- and post-recycled water commissioning, and
to determine savings attributed to a dual reticulated recycled water supply scheme (Willis et al.,
2010a). The end use evaluation of a dual reticulated region is the first of its kind, both nationally
and internationally.
The pre-commissioning Phase 1 component of the study was completed in 2009. The objectives
of this phase as detailed by Willis et al. (2010a) included:
Determine the recycled water pre-commissioning end uses for a statistically significant
sample of PC households;
Survey households participating in the end use study to determine demographics,
attitudes, preferences and behaviours with respect to recycled water; and
Chapter 10: Residential potable and recycled water end uses in a dual reticulated supply system
- 229 -
Predict the uptake of recycled water end uses and compare against actual end use break
downs post-commissioning.
Recycled water in the PC region is supplied through a separate recycled water pipeline for toilet
flushing and irrigation; leakage also occurs on this line. Phase 1 of the PC End Use Study
determined that toilet flushing behaviours would remain relatively similar but that irrigation
would alter depending on a variety of factors such as water restrictions, recycled water pricing,
climate and awareness campaigns. Phase 1 resulted in the development of a predictive uptake
model of recycled water for the PC area based on these influencing factors. The predictive
model calculated that the most likely total recycled water consumption post-commissioning
would be 53 litres per person per day (L/p/d) or 30.5% of total household consumption. Of this,
toilet usage was 21.7 L/p/d, leakage was 0.7 L/p/d and irrigation was 30.6 L/p/d. The lower least
likely estimates were 48 L/p/d or 28.4% with irrigation being 25.6 L/p/d and leakage and toilet
usage remaining the same as the most likely estimate. The upper least likely estimate was 64.2
L/p/d or 34.7% recycled water use with 42.8 L/p/d for irrigation consumption and leakage and
toilet usage remaining the same as the most likely estimate (Willis et al., 2010a). In December
2009, recycled water was supplied to the PC area. This triggered the commencement of Phase 2
of the PC End Use Study, namely the measurement of post-commissioning end use water
consumption in the PC area. This paper details the results of Phase 2 of the PC End Use Study.
10.3 Objectives and Scope of the Paper
The objectives of Phase 2 of the PC End Use Study are:
Determine the end uses for a statistically significant sample of PC households post-
commissioning of recycled water using quantitative and qualitative data sources and
analysis techniques;
Compare dual (potable and recycled supply) and single (potable only) reticulated water
supply schemes;
Undertake a comparison of measured recycled water consumption post- commissioning
of recycled water in the PC region against the PC dual reticulation demand forecast
model developed in Phase 1 of this study; and
Develop a tool and investigate average daily diurnal demand patterns at an end use level
for the PC dual reticulated region and the single reticulated control group.
This paper presents the results for the above stated objectives for Phase 2 of the study. To
achieve the above stated objectives, a variety of collected quantitative and qualitative data sets
and analysis techniques/tools were utilised including seasonal climatic data, bulk supply data,
water end use data, qualitative water audits, questionnaire surveys and an end use diurnal
Domestic End Use Investigation: WDM and Dual Reticulation, R.M. Willis (2010)
- 230 -
pattern software tool. The method carried out to satisfy the objectives of Phase 2 of the study
are summarised below:
1. Revalidate data collected through Phase 1 questionnaire survey, which obtained detailed
descriptive information such as household occupants, resident age, family income,
ownership status and education level;
2. Obtain seasonal climatic data and bulk supplied water consumption data for potable and
recycled water for the duration of the study;
3. Utilise the sample of recruited households in the single and dual reticulated PC region
from Phase 1 of the study to obtain actual end use water consumption from both the
potable and recycled water lines. This data was collected utilising high resolution
Actaris CTS-5 water meters (0.014 L/pulse) recording to DataCell D-CZ21020 data
loggers at 10 second intervals;
4. Conduct end use analysis procedure using collected high resolution flow data inputted
into Aquacraft’s Trace Wizard© software, with the categorisation process aided by
household stock inventory, qualitative household behaviour and descriptive data
solicited from households sampled. The end use analysis quality assurance procedure
detailed by Willis et al. (2010a) was adhered to, which included the use of qualitative
water consumption behaviour data to identify and categorise water flow traces. Such
qualitative information is critical for ensuring that flow trace data is accurately
disaggregated into a registry of water end use events;
5. Compile the end use water consumption summaries for each household, which served
as the post-commissioning end use data set;
6. Revisit the Phase 1 recycled water prediction model to compare the differences in actual
post-commissioning end use consumption in the PC dual reticulated region.
7. Develop a diurnal pattern tool using ‘Borland C Builder’, which is a Microsoft (MS)
Windows ‘Multiple Document Interface’ (MDI) compliant software. The ‘Diurnal’
program processes MS-Access data files produced by the auxiliary Trace Wizard©
software with variable time series intervals ranging from hourly to five minute intervals;
and
8. Undertake analysis using the ‘Diurnal’ tool for the collaboration of end use water
consumption data across required time intervals for daily use.
For a comprehensive explanation of the methods undertaken to complete the GCWSEU study,
readers are referred to Willis et al., (2009b), Willis et al., (2010a) and Willis et al., (2010b). The
results of the above described method are detailed below.
Chapter 10: Residential potable and recycled water end uses in a dual reticulated supply system
- 231 -
10.4 Pimpama Coomera End Use Water Consumption Study
10.4.1 Pre-Commissioning of recycled water to Pimpama Coomera region
Phase 1 of the PC End Use Study identified factors reported to influence the uptake of recycled
water. Climate was predicted to have the most significant impact on irrigation hence, an
overview of climatic variables including rainfall and temperature and coinciding bulk recorded
supply were summarised to establish appropriate periods to monitor end use water consumption
post-commissioning (Figure 10-2).
0
5
10
15
20
25
30
35
0
100
200
300
400
500
600
Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun
Ra
infa
ll (m
m)
/ B
ulk
Re
s. (
L/p
/d)
Te
mp
era
ture
(°C
)
Month
Average Max Temperature and Rainfall
2008/09 Rainfall (mm) 2009/10 Rainfall (mm)
2009/10 Bulk Res. Supply GC City (L/p/d) 2008/09 Bulk Res. Supply GC City (L/p/d)
2008/09 Max Temp (°C) 2009/10 Max Temp (°C)
Figure 10-2 Rainfall and maximum temperature with bulk recorded supply for Gold Coast City over the
duration of the Gold Coast Watersaver End Use study July 2008 – June 2010
Climatic trends shown in Figure 10-2 follow sub-tropical patterns of high temperature and
rainfall throughout summer and lower temperatures and rainfall in winter. Figure 10-2 illustrates
that the first pre-commissioning data collection period in winter 2008, occurred within an un-
seasonally high rainfall period (Phase 1). This is reflected in both the city wide bulk supply and
end use data being the lowest recorded over the study period. The summer pre-commissioning
data log occurred in December 2008 when the Gold Coast city was under Queensland Water
Commission (QWC) medium level restrictions of Target 200 L/p/d. November 2008
experienced extreme rainfall of 440.6mm. This was the third highest rainfall month recorded on
the Gold Coast between 2001 and 2010. December 2008 also experienced high rainfall volumes
of 123.8mm. Understandably, bulk supplied residential consumption in December was low at
176.9 L/p/d, with monthly consumption increasing to 196.3 L/p/d in January 2009. The total
Domestic End Use Investigation: WDM and Dual Reticulation, R.M. Willis (2010)
- 232 -
pre-commissioning end use water consumption in the dual and single reticulated regions,
recorded in summer 2008/09, is detailed in Figure 10-3. Single reticulated region use is
presented in Figure 10-3a, the dual reticulated region potable and recycled combined supply in
Figure 10-3b while, Figure 10-3c and d present the dual reticulated regions potable and recycled
supply lines separately.
Figure 10-3 Pre-commissioning end use water consumption data (summer 08/09)
The average summer pre-commission end use water consumption across the single and dual
reticulated regions was recorded as 146.9 L/p/d (n=127). Total consumption for the single
reticulated region was 158.4 L/p/d (Figure 10-3a) while the dual reticulated region was 9%
lower at 143.5 L/p/d (Figure 10-3b). The end use consumption volumes were relatively similar
but just slightly lower in the dual reticulated region for shower, clothes washer, tap, toilet and
Toilet (Rec)21.9 L/p/d
76.2%
Irrigation (Rec)6.2 L/p/d21.5%
Leak (Rec)0.7 L/p/d
2.3%
Clothes Washer
29.7 L/p/d25.8%
Shower45.6 L/p/d
39.8%
Tap26.3 L/p/d
22.9%
Dishwasher2.2 L/p/d
1.9%
Bathtub2.6 L/p/d
2.3%
Irrigation (Pot)6.9 L/p/d
6.1%
Leak (Pot)1.4 L/p/d
1.2%
Clothes Washer
29.7 L/p/d20.7%
Shower45.6 L/p/d
31.8%
Tap26.3 L/p/d
18.3%
Dishwasher2.2 L/p/d
1.5%
Bathtub2.6 L/p/d
1.8%
Toilet (Rec)21.9 L/p/d
15.3%
Irrigation (Pot)6.9 L/p/d
4.8%
Irrigation (Rec)6.2 L/p/d
4.3%
Leak (Pot)1.4 L/p/d
1.0%
Leak (Rec)0.7 L/p/d
0.5%Clothes Washer
28.3 L/p/d17.9%
Shower51.1 L/p/d
32.3%Tap28.6 L/p/d
18.1%
Dishwasher2.1 L/p/d
1.3%
Bathtub1.4 L/p/d
0.9%
Toilet (Pot)21.2 L/p/d
13.4%
Irrigation (Pot)12.7 L/p/d
8.0%
Leak (Pot)13.0 L/p/d
8.2%
Total: 158.4 L/p/d Total: 143.5 L/p/d
Total: 28.8 L/p/d Total: 114.7 L/p/d
a. Daily per capita consumption summer pre (L/p/d):
Single Reticulated (n=29)
b. Daily per capita consumption summer pre (L/p/d):
Dual Reticulated (n=98)
d. Daily per capita consumption summer pre (L/p/d):
Dual Reticulated (Recycled line only) (n=98)
c. Daily per capita consumption summer pre (L/p/d):
Dual Reticulated (Potable line only) (n=98)
Chapter 10: Residential potable and recycled water end uses in a dual reticulated supply system
- 233 -
dishwasher. In this data logging period, total irrigation consumption in the dual reticulated
region was practically equal with the single reticulated region being 13.1 L/p/d (potable +
recycled Figure 10-3b) or 9%, while the single reticulated region was 12.7 L/p/d or 8 (Figure
10-3a). In PC, irrigation on the recycled water line was just slightly lower than the potable water
line, being 6.2 L/p/d for recycled versus 6.9 L/p/d for potable. This may be due to the lack of
community awareness programs encouraging the use of recycled for irrigation in the dual
reticulated region. Recycled line toilet use accounted for 21.9 L/p/d while leakage was 0.7 L/p/d
(Figure 10-3d). In the summer pre-commissioning phase, recycled water consumption
accounted for 28.8 L/p/d or 20% of total end use in the dual reticulated region. Overall, other
end uses (shower, clothes washer, tap, toilet etc.) were very similar in volumetric consumption
across both regions. Clothes washer is slightly lower in the single reticulated region while
shower consumption is slightly higher, compared to the dual reticulated region. Bathtub usage is
higher in the dual than the single reticulated region (2.6 versus 1.4 L/p/d) due to young children
occupation. Leakage is also significantly higher in the single reticulated region (13.0 versus 2.0
L/p/d) due to two single reticulated homes experiencing week long leakage during the
monitoring period. This leakage volume is the reason for higher weekly average consumption in
the single reticulated region. Overall, the total volumetric consumption in the single and dual
reticulated regions was low due to high rainfall during the summer pre-commissioning data
collection period.
10.4.2 Post-Commissioning of recycled water to Pimpama Coomera region
As of the 1st of December 2009, recycled water was supplied to the PC region, which triggered
data collection for the summer post-commissioning period (i.e. Phase 2). The commissioning of
recycled water was launched with an extensive awareness campaign promoting its supply and
encouraging the use of recycled water in PC. Post-commissioning end use water consumption
data was sampled over the summer 2009/10 season, identified as December 2009 to the
beginning of March 2010. Two week data sets were taken from dissected samples over the
season to account for seasonal affects (predominately rainfall) on irrigation usage. In total, the
dual and single reticulated sample size was n=100 and n=34, respectively. During the post-
commissioning collection periods, Gold Coast City was on QWC’s permanent water
conservation target level of 200 L/p/d. Figure 10-2 shows that the end use water consumption
data collection period in December 2009, occurred when city wide bulk supplied water peaked
to its highest level (224.36 L/p/d), while February and March 2010 had reduced bulk values due
to lower temperatures and higher rainfall in these months (Figure 10-2). Understandably, the
irrigation end use category is the most variable and difficult to sample reliably. The strategy to
collect end use data from a portion of households over the season serves to provide a mean
irrigation volume for the sample in the season, but readers should note that irrigation end use
values have much higher variance around the mean than indoor end uses. Figure 10-4 illustrates
Domestic End Use Investigation: WDM and Dual Reticulation, R.M. Willis (2010)
- 234 -
the end use water consumption, post-commissioning of recycled water, in the single and dual
reticulated regions. Single reticulated region use is presented in Figure 10-4a, the dual
reticulated region potable and recycled combined supply in Figure 10-4b while, Figure 10-4c
and d detail the dual reticulated potable and recycled supply lines separately.
Figure 10-4 Post-commissioning end use water consumption data (summer 09/10)
As discussed, the overall total water consumption increase from pre-commissioning in 2008 to
post-commissioning 2010 data was due; to high rainfall in the 2008 logging periods, the capture
of a record high consumption period in December 2009 and a gradual increase in total
consumption across the study due to relaxed water restrictions and water conservation
messages. Recycled water consumption post-commissioning in the PC region saw a significant
increase of recycled water for irrigation purposes. Weather conditions during the post-
Toilet (Rec)27.5 L/p/d
46.6%
Irrigation (Rec)28.9 L/p/d
48.9%
Leak (Rec)2.7 L/p/d
4.5%Clothes Washer
28.9 L/p/d23.2%
Shower43.3 L/p/d
34.8%
Tap28.0 L/p/d
22.5%
Dishwasher2.2 L/p/d
1.8%
Bathtub2.6 L/p/d
2.1%
Irrigation (Pot)18.7 L/p/d
15.0%
Leak (Pot)0.8 L/p/d
0.7%
Clothes Washer
28.9 L/p/d15.8%
Shower43.3 L/p/d
23.6%
Tap28.0 L/p/d
15.2%
Dishwasher2.2 L/p/d
1.2%
Bathtub2.6 L/p/d
1.4%
Toilet (Rec)27.5 L/p/d
15.0%
Irrigation (Pot)18.7 L/p/d
10.2%
Irrigation (Rec)28.9 L/p/d
15.7%
Leak (Pot)0.8 L/p/d
0.4%Leak (Rec)2.7 L/p/d
1.5%
Clothes Washer
36.9 L/p/d21.5%
Shower52.7 L/p/d
30.6%
Tap33.3 L/p/d
19.4%
Dishwasher1.4 L/p/d
0.8%
Bathtub1.6 L/p/d
1.0%
Toilet (Pot)23.1 L/p/d
13.5%
Irrigation (Pot)21.9 L/p/d
12.7%
Leak (Pot)1.0 L/p/d
0.6%
Total: 171.9 L/p/d Total: 183.6 L/p/d
Total: 124.5 L/p/d Total: 59.1 L/p/d
a. Daily per capita consumption summer post (L/p/d):
Single Reticulated (n=34)
b. Daily per capita consumption summer post (L/p/d):
Dual Reticulated (n=100)
d. Daily per capita consumption summer post (L/p/d):
Dual Reticulated (Recycled line only) (n=100)
c. Daily per capita consumption summer post (L/p/d):
Dual Reticulated (Potable line only) (n=100)
Chapter 10: Residential potable and recycled water end uses in a dual reticulated supply system
- 235 -
commissioning period were generally dryer than those experienced in the pre-commissioning
phase albeit both a high and low rainfall and consumption period of water use were captured.
The average consumption post-commissioning of recycled water to the PC region was 183.6
L/p/d (Figure 10-4b), a significant increase on pre-commissioning consumption of 143.5 L/p/d
(Figure 10-3b). Total consumption post-commissioning (183.6 L/p/d) consisted of 59.1 L/p/d or
32.2% being consumed on the recycled water line and 124.5 L/p/d or 67.8% consumed on the
potable line (Figure 10-4b). Recycled water irrigation was 28.9 L/p/d and potable irrigation was
18.7 L/p/d, both significantly higher than that recorded pre-commissioning. Recycled line toilet
use and leakage were at 27.5 L/p/d and 2.7 L/p/d respectively (Figure 10-4d), which is higher
than recorded pre-commissioning. Other end uses remained similar to those experienced pre-
commissioning with shower and clothes washer accounting for 43.3 and 28.9 L/p/d respectively
(Figure 10-4c). Overall, the major change in end use water consumption post-commissioning
was in irrigation, with other end uses remaining similar pre-and post-commissioning of recycled
water to the PC region.
Figure 10-4a demonstrates that the single reticulated regions end use data varies somewhat from
the dual reticulated region (Figure 10-4b). Firstly, total consumption is only 171.9 L/p/d, which
was 11.7 L/p/d or 6% less than the dual reticulated region. Irrigation in the single reticulated
region was 21.9 L/p/d which was similar to that recorded in PC on the potable line (18.7 L/p/d).
Clothes’ washing was slightly higher in the single reticulated region (36.9 versus 28.9 L/p/d)
with shower usage also higher (52.7 versus 43.3 L/p/d). Toilet usage was lower in the single
reticulated region being 23.1 L/p/d compared with 27.5 L/p/d in PC. Tap, dishwasher and
potable leakage were similar with bath use remaining higher in PC as has been the trend
throughout the study duration. As a note to readers, toilet end use demand averages reported
herein are more reliable and transferable to other schemes than irrigation. Irrigation end use
demand averages can fluctuate from season to season and year to year due to localised climatic
conditions (e.g. high rainfall summer reduces demand substantially) and are also less
transferable to other regions with different climatic conditions.
10.4.3 Comparison of Phase 1 prediction with Phase 2 data
When comparing the results of Phase 2 of the PC End Use study (summer post-commissioning
end use) with the recycled water uptake predicted in Phase 1 of the study (pre-commissioning
prediction based on winter 2008 data) the actual recycled water end use falls between the most
likely estimate, 53 L/p/d or 30.5% and the upper estimate of 64.2 L/p/d or 34.7% (Willis et al.,
2010a). The Phase 2 summer post-commissioning total recycled water usage was 59.1 L/p/d or
32.2% of total household end use (Figure 10-4d and b). Post-commissioning recycled water
consumption included irrigation 28.9 L/p/d, toilet 27.5 L/p/d and leakage 2.7 L/p/d. The pre-
commissioning most likely end use estimates from Phase 1, included irrigation of 30.6 L/p/d,
Domestic End Use Investigation: WDM and Dual Reticulation, R.M. Willis (2010)
- 236 -
toilet 21.7 L/p/d and leakage 0.7 L/p/d. As seen in Figure 10-4, a difference in post-
commissioning end use was predicted for irrigation due to a likely change in demand instigated
by the presence of recycled water, while toilets and leakage consumption was not altered. The
pre-commissioning upper end use estimates included increased irrigation usage of 41.8 L/p/d.
When comparing recycled water end uses pre- and post-commissioning, recorded irrigation of
28.9 L/p/d (post-commissioning) was very close to the most likely estimate of 30.6 L/p/d. The
variation between the most likely prediction and actual post-commissioning end use is due to
the increase in toilet and leakage use. This demonstrates that the indicators and methodology
used to predict recycled water irrigation uptake post-commissioning was relatively accurate and
provides rigour to the utilisation of this predictive model for recycled irrigation uptake. While,
the differences between the Phase 1 recycled water uptake prediction and the Phase 2 actual
recycled water consumption are not dramatically different, this variation does support the need
to undertake data collection to verify predictions and assumptions. This data also allows for the
strengthening and validation of the Phase 1 PC End Use Study recycled water uptake prediction
model. Some alteration will need to be made to the predictive model to include an increase in
consumption for both toilet and leakage coinciding with an increase in average daily demand.
10.5 Compilation of end use average hourly diurnal patterns
10.5.1 Developed end use diurnal pattern software tool
A software tool was developed to assimilate data files containing household end use water
consumption events into patterns of average hourly use. The software was designed to read
water usage events from analysed end use data files (interchangeable Trace Wizard/MS-Access)
and collate the individual fixture use events into hourly usage periods across a day. The
tabulated data can be grouped within user selected time periods, from hourly (24 graph points)
through to five minute intervals (288 graph data points). This function enables the display of
data to the resolution detail required within an average day 24 hour period. The software can
collate single and/or multiple files as indicated by the user, in order to explore the determination
of water usage from particular regions, suburbs or homes with a particular socioeconomic status
or varying occupancy. The software outputs compiled data in the form of a spreadsheet and/or
graph. As further elaborated below, end use diurnal patterns, which are premised on actual high
resolution smart metering data for a particular region, provide essential information for a range
of infrastructure planning functions.
10.5.2 Diurnal patterns of consumption
Average hourly water consumption patterns demonstrate daily water demand and peak usage
throughout the day. Diurnal patterns were determined for both the single and dual reticulated
Chapter 10: Residential potable and recycled water end uses in a dual reticulated supply system
- 237 -
regions for total household consumption along with the dual reticulated potable and recycled
supply lines only (Figure 10-5).
Figure 10-5 Average hourly diurnal pattern profile: single and dual reticulated regions
Figure 10-5 illustrates the variation in daily water demand between the single and dual
reticulated regions. While total daily consumption was slightly higher in the dual reticulated
region, the single reticulated regions maximum peak was greater than that seen in the dual
reticulated region. Interestingly, the morning peak in the single reticulated region inclines
sharply to just above 22 litres per hour per person per day (L/h/p/d) between 8 am and 9am
(Figure 10-5), while the dual reticulated morning peak (total supply) rises more gradually to
reach a peak of just 16 L/h/p/d at 8am (Figure 10-5). This trend is reversed in the evening, with
the dual reticulated region peaking at 19 L/h/p/d at 7pm (total supply), while the single
reticulated evening peak is much more gradual reaching 12 L/h/p/d at 6pm. The diurnal pattern
for the single reticulated region is similar to the trend determined by Mead (2008) but differs to
that found by Roberts (2005). The apparent variations in diurnal characteristics and peak
demand between the supply regions (Figure 10-5) illustrate the impact of varying socio-
demographics and behaviours between the sample groups. When comparing the single
reticulated region with the dual reticulated regions potable supply the morning peak ranges from
22 L/h/p/d to just 12 L/h/p/d while the evening peak flows are both at 12 L/h/p/d. This
significant reduction in potable peak morning flow demonstrates the variation in potable
demand that can exist between single and dual reticulated supply regions. To further explore the
apparent differences in diurnal pattern between traditional single reticulated and dual reticulated
regions, end use diurnal patterns were examined.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
Single Reticulation Total 0.68 0.50 0.53 0.83 0.96 2.81 8.64 21.52 21.86 13.51 10.26 8.18 9.50 8.02 7.50 8.00 10.90 12.48 10.29 7.73 9.02 6.11 3.98 2.15
Dual Reticulation Total 1.23 2.63 2.56 2.04 2.04 7.04 12.01 15.80 12.89 12.43 11.81 8.09 6.59 6.79 8.73 7.04 13.54 17.57 18.96 18.27 10.22 8.22 5.89 2.76
Dual Reticulation (Potable line only) 0.60 0.96 0.87 0.42 0.99 4.05 8.54 11.96 10.07 9.97 8.13 6.11 4.85 4.60 6.99 5.24 8.18 12.23 11.59 8.42 7.29 5.11 3.94 1.67
Dual Reticulation (Recycled line only) 0.63 1.67 1.69 1.63 1.05 2.99 3.47 3.84 2.81 2.46 3.68 1.98 1.74 2.20 1.74 1.80 5.36 5.34 7.38 9.86 2.93 3.11 1.95 1.09
0
2
4
6
8
10
12
14
16
18
20
22
24
Ave
rag
e d
aily
diu
rnal
co
nsu
mp
tion
(L/h
/p/d
)
Hour
Single Reticulation Total
Dual Reticulation Total
Dual Reticulation (Potable line only)
Dual Reticulation (Recycled line only)
Domestic End Use Investigation: WDM and Dual Reticulation, R.M. Willis (2010)
- 238 -
10.5.3 End use diurnal patterns of consumption
Daily end use consumption patterns allow for the determination of water use events that
contribute to peak demands. Figure 10-6 present the diurnal patterns of the single reticulated
region (Figure 10-6a), dual reticulated region potable and recycled combined supply (Figure
10-6b), dual reticulated potable only (Figure 10-6c) and dual reticulated recycled line only
(Figure 10-6d). Figure 10-6a demonstrates that in the single reticulated region the largest peak
occurred between 8 and 9am with another small peak at 1pm and an evening peak at 6pm. The
sharp morning peak is predominantly due to showering and clothes washing. All other
household end uses are also higher in this morning peak with the exception of leakage.
Irrigation use appears to peak earlier in the morning than other end uses demonstrating an
alignment with current water restrictions and awareness messages that encourage outdoor
watering in early morning and late afternoon. Evening irrigation occurred between 5 to 7pm.
Leakage remains relatively consistent while dishwasher use occurred in the morning, after lunch
and after dinner. Bath use peaked in the morning while, tap use was at its highest between 8 to
9am and 6 to 8pm. Toilet flushing was highest in the morning and relatively consistent
throughout the day. Clothes washer use peaked in the morning between 7 and 9am and dropped
drastically after 10pm. In the single reticulated region shower use is the primary contributor to
the morning peak while, evening peak usage was due to irrigation and shower end use.
The end use pattern of daily demand for the PC dual reticulated region total (Figure 10-6b)
exhibited distinctive differences when compared with the single reticulated region (Figure
10-6a). Figure 10-6b illustrates the morning peak at 8am, with another small peak at 3pm, while
the greatest evening peak occurred between 6 to 8pm. Leakage is much lower in the dual
reticulated region generally present during the waking hours of the day. Dishwasher use peaks
in the morning and evenings. Bath use peaks in the evenings, while tap usage had similar peaks
in the morning and evenings with consistent use throughout the day. In PC (Figure 10-6b),
showering is the highest morning end use, as seen in the single reticulated region (Figure
10-6a). Showering peaks at 8am and between 6 to 7pm in the evening. Clothes washer use also
contributes to the morning peak between 8am to 10am, slightly later than the single reticulated
region. Irrigation on the potable line peaks at 3pm and again between 6 to 7pm.
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a. Diurnal consumption: Single reticulated region (potable line only) b. Diurnal consumption: Dual reticulated region (combined potable + recycled)
d. Diurnal consumption: Dual reticulated region (Recycled line only)
c. Diurnal consumption: Dual reticulated region (Potable line only) c. Diurnal consumption: Dual reticulated region (Potable line only)
Figure 10-6 End use hourly diurnal pattern profile: single and dual reticulated regions
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Figure 10-6 End use hourly diurnal pattern profile: single and dual reticulated regions
On the recycled water supply line (Figure 10-6b), leakage is highest between 10am and 12pm
and remains relatively consistent across the rest of the day. Toilet use with recycled water is
relatively even across the waking hours of the day with a slight peak in the morning and
evening. Recycled water irrigation is higher between 2 to 4am and inclines sharply in the
evening between 6 to 8pm (Figure 10-6b). Irrigation on the recycled line is the primary
contributor of the high evening peak; shower use is the highest contributor to the morning peak
(Figure 10-6b).
10.5.4 Variation in peaks between single and dual reticulated supply schemes
Dual supply regions introduce two separate reticulated supply sources to reduce the average
daily and peak demand on potable supply systems as experienced in single reticulated regions.
Figure 10-6c and d present the diurnal demand experienced in the dual reticulated system on the
potable and recycled water pipelines, respectively. When comparing the single reticulated
regions diurnal demand (Figure 10-6a) with the dual reticulated regions potable diurnal demand
(Figure 10-6c) a significant reduction in peak morning demand is apparent while, the evening
demand remains relatively similar. The recycled water supply pipeline removes toilet flushing,
some irrigation and leakage in both the morning and evening peaks. The recycled water supply
reduces the peak morning demand by 4 L/h/p/d and the evening peak by 10 L/h/p/d in the dual
reticulated region when looking at the combined potable and recycled water supply (Figure
10-6b). This is a significant saving when considering the sizing of water supply infrastructure
for peak demands. The use of recycled water for clothes washing (occurring in some dual
reticulated regions in Australia) has the potential to reduce the peak morning demand by an
additional 4 L/h/p/d. While, the diurnal patterns of demand do differ between the single and
dual reticulated supply regions, the introduction of a recycled water supply network does reduce
the average daily demand and peak demands when compared with traditional single reticulated
supply. Understanding end use daily patterns of demand has significant application and
implication for sustainable urban water planning and management.
10.6 Conclusions, Implications and Future Directions
The results from this end use investigation provide much needed data for the verification of end
use water consumption and daily demand patterns in single and dual reticulated water supply
regions. This is a unique world first investigation predicting and measuring actual end use water
consumption in a dual reticulated water supply region. The recycled water uptake, post-
commissioning (Phase 2), was higher than initially predicted pre-commissioning (Phase 1)
primarily due to increases in toilet and leakage consumption. The predictive model focussed on
post-commissioning increases of irrigation which, resulted in the predicted versus actual
Chapter 10: Residential potable and recycled water end uses in a dual reticulated supply system
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recycled irrigation end use being very close. Post-commissioning of recycled water in the PC
region resulted in this supply providing 59.1 L/p/d or 32.2% of total daily consumption. Of this,
irrigation on the recycled water line was 28.9 L/p/d or 15.7% of total daily consumption
compared to the predicted most likely uptake of 30.6 L/p/d. Understanding the baseline recycled
water consumption, and the variation in irrigation and other end uses through high and low
demand periods from climatic conditions, provides data to assist in predicting and modelling
yearly demand and supply for potable and recycled water infrastructure in dual reticulated
regions. This also applies to single reticulated regions.
Validating the daily diurnal patterns for both single and dual reticulated regions demonstrates
maximum and average demands in these supply schemes and identifies the end uses which
attribute to peaks. Such data is invaluable for modelling and forecasting demand and supply and
for verification of assumptions in desired standards of service and other water services
infrastructure planning documentation. The end use diurnal patterns determined for the PC
region provides support for the implementation of dual reticulated supply schemes as they can
provide significant reductions in peak demands on potable water infrastructure. The potable
water demand peaked at 12 L/p/h/d in the dual reticulated region compared with 22 L/p/h/d in
the single reticulated region. Such significant reductions in peak demand would allow for
reductions in pipe sizing and treatment volumes of potable water for this region.
The collected end use data from the PC End Use Study will inform the sizing of infrastructure,
can assist in delaying infrastructure upgrades and also validating and directing water treatment
and pumping requirements of potable and recycled water to regions in the Gold Coast,
Australia. Understanding recycled water demand also allows for accurate forecasting of
recycled water discharges for the environment. The data also provides verification of the
assumptions made in the PCWF Master Plan for recycled and potable water consumption and
savings. Data can also be used to inform the development of demand management messages to
offset peak usage periods i.e. encouraging showering in later hours of the day when possible and
to encourage PC residents to use recycled water almost exclusively for external irrigation.
Overall, the results from this study support the application of dual reticulated schemes through
significant reductions in peak demand on potable water supply infrastructure and by the
reduction of average potable water demand by 59.1 L/p/d or 32.2%. The diurnal patterns of
daily demand differ extensively between the single and dual reticulated regions demonstrating
the unique consumption patterns in these alternative supply schemes. Information gathered
through this study will assist in the refinement of predictions and assumptions for both end use
and diurnal demands for single and dual reticulated regions water infrastructure planning. It will
allow for accurate forecasting and modelling resulting in informed decision making for water
Domestic End Use Investigation: WDM and Dual Reticulation, R.M. Willis (2010)
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infrastructure sizing and upgrades and future supply and demand requirements in the Gold
Coast.
10.7 References
ABS (2010) Australia's Environment: Issues and Trends 2010. Australian Bureau of Statistics, Canberra.
American Water Works Association (1999) Residential End Uses of Water. Aquacraft, Inc. Water Engineering and Management, Denver, CO.
Anderson, J. M. (1996) The potential for water recycling in Australia: Expanding our horizons. Desalination, Vol 106:1-3, pp. 151-156.
Barlow, M. (2009) Notes for Opening Keynote Australian Water Summit, 1 April 2009. Australian Water Summit.
Birrell, B., Rapson, V. & Smith, F. (2005) Impact of Demographic Change and Urban Consolidation on Domestic Water Use. Water Services Association of Australia Inc, Melbourne.
Commonwealth of Australia (2008a) Drought. online article, available at http://www.bom.gov.au/lam/climate/levelthree/c20thc/drought.htm Accessed 20/03/08. Bureau of Meteorology.
Commonwealth of Australia (2008b) Living with Drought. online article, available at http://www.bom.gov.au/climate/drought/livedrought.shtml Accessed 14/03/08. Bureau of Meteorology.
Commonwealth of Australia (2010) Australian Climate Change and Variability. Online article, available: http://www.bom.gov.au/climate/change/aus_cvac.shtml. Bureau of Meteorology.
DNRM (2005) Planning Guidelines for Water Supply and Sewerage. Department of Natural Resources and Mines.
Fearnley, E. J., Thomas, K. D., Luscombe, A. & Cromar, N. (2004) Determination of water usage rates and water usage patterns in residential recycling initiative in South Australia. Environmental Health, Vol 4:2, pp. 72-81.
Gato, S. (2006) Forecasting Urban Residential Water Demand. School of Civil, Environmental and Chemical Engineering. RMIT, Melbourne.
GCW (2004) Pimpama Coomera Waterfuture Master Plan March 2004. Gold Coast, Gold Coast Water and Gold Coast City Council.
GCW & GCCC (2007) The Gold Coast Waterfuture Strategy 2006-2056. Gold Coast, Gold Coast Water and Gold Coast City Council
Giurco, D., Carrard, N., McFallan, S., Nalbantoglu, M., Inman, M., Thornton, N. & White, S. (2008a) Residential end-use measurement guidebook: a guide to study design, sampling and technology. Prepared by the Institute for Sustainable Futures, UTS and CSIRO for the Smart Water Fund, Victoria.
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Giurco, D., Carrard, N., Wang, Z., Inman, M. & Nguyen, M. (2008b) Innovative smart metering technology and its role in end-use measurement. Water Efficiency 2008. Gold Coast.
Heinrich, M. (2007) Water End Use and Efficiency Project (WEEP) - Final Report. BRANZ Study Report 159. Judgeford, New Zealand, Branz.
Hurlimann, A. & McKay, J. (2006) Urban Australians using recycled water for domestic non-potable use—An evaluation of the attributes price, saltiness, colour and odour using conjoint analysis. Journal of Environmental Management, Vol: 83, pp. 93-104.
Inman, D. & Jeffrey, P. (2006) A review of residential water conservation tool performance and influences on implementation effectiveness. Urban Water Journal, Vol 3:3, pp. 127-143.
Loh, M. & Coghlan, P. (2003) Domestic Water Use Study. Perth, Water Corporation.
Marks, J. S. & Zadoroznyj, M. (2005) Managing Sustainable Urban Water Reuse: Structural Context and Cultures of Trust. Society & Natural Resources, Vol 18:6, pp. 557-572.
Mayer, P., DeOreo, W., Towler, E., Martien, L. & Lewis, D. (2004) Tampa Water Department residential water conservation study: The impacts of high efficiency plumbing fixture retrofits in single-family homes. Aquacraft, Inc Water Engineering and Management, Tampa.
Mead, N. (2008) Investigation of Domestic End Use. Faculty of Engineering & Surveying. The University of Southern Queensland, Toowoomba.
Mitchell, V. G. (2006) Applying Integrated Urban Water Management Concepts: A Review of Australia Experience. Journal of Environmental Management, Vol. 37:5, pp. 589-605.
Po, M., Nancarrow, B. E., Leviston, Z., Porter, N. B., Syme, G. J. & Kaercher, J. D. (2005) Predicting Community Behaviour in Relation to Wastewater Reuse. CSIRO, Canberra.
Roberts, P. (2005) Yarra Valley Water 2004 Residential End Use Measurement Study. Melbourne, Yarra Valley Water.
Sydney Water (2008) Recycled water in the Rouse Hill area - saving drinking water for drinking. Online article, accessed 10/03/08. Available at: http://www.sydneywater.com.au/Publications/FactSheets/FINAL_Rouse_Hill_Brochure_Feb_08.pdf#Page=1.
Turner, A. & White, S. (2006) Does demand management work over the long term? What are the critical success factors? Sustainable Water in the Urban Environment II Conference.
Turner, A., White, S., Beatty, K. & Gregory, A. (2005) Results of the largest residential demand management program in Australia. Institute for Sustainable Futures, University of Technology. Sydney Water Corporation, Sydney, NSW
Turner, A., White, S., Kazaglis, A. & Simard, S. (2007) Have we achieved the savings? The importance of evaluations when implementing demand management. Water Science and Technology: Water Supply, Vol 7:5-6, pp. 203-210.
Webb, T. (2007) Towards Sustainable Water Futures in Western Sydney. In the pipeline: a symposium - new directions in cultural research on water. University of Western Sydney, NSW, Sydney.
White, S. (2001) Demand Management and Integrated Resource Planning in Australia. Efficient Use and Management of Water for Urban Supply. Madrid.
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White, S. & Turner, A. (2003) The role of effluent reuse in sustainable urban water systems: untapped opportunities. National Water Recycling in Australia Conference. Brisbane, September 2003.
Willis, R., Stewart, R. & Emmonds, S. (2010a) Pimpama-Coomera dual reticulation end use study: pre-commission baseline, context and post-commission end use prediction. IWA Water, Science and Technology: Water Supply, Vol 10:3, pp. 302-314, DOI: 10.2166/ws.2010.104.
Willis, R., Stewart, R., Panuwatwanich, K., Capati, B. & Giurco, D. (2009) Gold Coast Domestic Water End Use Study. Journal of Australian Water Association Vol 36:6, pp. 79-85.
Willis, R. M., Stewart, R. A., Panuwatwanich, K., Jones, S. & Kyrakides, A. (2010b) Alarming visual display monitors affecting shower end use water and energy conservation in Australian residential households. Journal of Resources, Conservation and Recycling, Vol 54:12, pp. 1117-1127, doi:10.1016/j.resconrec.2010.03.004.
WSAA (2003) Urban Water Demand Forecasting and Demand Management: research needs review and recommendations. White, S. Robertson, J. Cordell, D. Jha, M. Milne, G. Institute for Sustainable Futures UTS for Water Services Association, Sydney.
WSAA (2008) Guide to Demand Management. Water Services Association Australia and Institute for Sustainable Futures, Sydney.
Zhou, S. L., McMahon, T. A., Walton, A. & Lewis, J. (2002) Forecasting operational demand for an urban water supply zone. Journal of Hydrology, 259, 189-202.
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Chapter 11
Conclusions, Contributions and Implications
Presented in this final chapter, is a summary of the key findings of this research. The
contributions and limitations of the research are detailed along with recommendations for future
research directions. The chapter begins with Section 11.1, which reiterates research objectives
and highlights the key outcomes which satisfied these objectives. Section 11.2 identifies the
theoretical and practical contributions made by this study. The limitations of the research and
suggestions for future study in the urban water management field are presented in Section 11.3.
Section 11.4 concludes the chapter and thesis discourse.
11.1 Research Objectives and Outcomes
The principle objectives of this research were: (1) to investigate end use water consumption
breakdowns in detached residential households; (2) to determine the potable water savings
attributed to water demand management initiatives and dual reticulated recycled water schemes
and; (3) to assess the relationship between consumer attitudes and end use consumption. More
specifically, it aimed to establish residential end uses in both traditional single reticulated
households and non-traditional dual reticulated households and to ascertain diurnal patterns for
both of these supply types in the context of the Gold Coast, Australia. Water demand
management initiatives investigated included water efficient devices and resource consumption
awareness devices. Socio-demographic factors were also examined to determine those that
significantly affected end use water consumption. Moreover, the link between attitudes and
residential end use water consumption was verified. These components culminated in the
development of a comprehensive domestic end use database for the Gold Coast as well as
evidence that supports the influence of water demand management and source substitution
measures, for conserving precious potable water supplies. To achieve the vast array of
objectives, a number of research activities were carried out. A summary of these research
activities and their associated outcomes are presented in Figure 11-1.
Domestic End Use Investigation: WDM and Dual Reticulation, R.M. Willis (2010)
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Phase 1: Knowledge Acquisition
Phase 2: Water End Use & Demand Management
Phase 3: Dual Reticulated Recycled Water
Stage 1a: Literature Review
Stage 1b: Set Research Objectives
Stage 1c: Research Method
Stage 2b: Obtain consenting sample
Stage 2c: Potable end use water consumption data
Stage 2d: Stock survey and water use behaviour audit
Stage 2e: Potable end use water consumption
Stage 2f: Questionnaire development, distribution and analysis
Stage 2g: Shower monitor investigation
Stage 3a: Predictive dual reticulated recycled water uptake model
Stage 3b: Dual reticulated recycled end use water consumption data collection and analysis
Stage 3c: Dual reticulated recycled water end use consumption
Stage 2a: End use water consumption design
PHASE STAGEOUTPUT/REFEREED
PUBLICATION
Chapter 1: Introduction
Chapter 2: Literature Review
Chapter 3: Research Method and Design
Chapter 5: Gold Coast Domestic Water End Use Study
Chapter 6: Revealing the impact of socio-demographics factors and efficient devices
on end use water consumption: case of Gold Coast, Australia
Chapter 7: Quantifying the influence of environmental and water conservation attitudes on household end use water
consumption
Chapter 8: Alarming visual display monitors affecting shower end use water
and energy conservation in Australian residential households
Chapter 9: Pimpama-Coomera dual reticulation end use study: pre-commission
baseline, context and post-commission end use prediction
Chapter 10: Domestic Dual Reticulated End Use Pimpama Coomera, Gold Coast,
Australia
Chapter 11: Conclusions, Contributions and Implication
Chapter 4:Situational Context and Descriptive Data Analysis
Pub
Pub
Pub
Pub
Pub
Pub
Pub = Referred Publication
Figure 11-1 Overarching mixed methods research design
Figure 11-1 illustrates the three phased approach undertaken to achieve the research objectives
and the outcomes of each phase/stage, predominantly in the form of a refereed journal
publication. Further detail on each phase and respective stages are presented below.
Chapter 11: Conclusions, Contributions and Implications
- 247 -
11.1.1 Knowledge acquisition
To establish a robust framework for the research, existing literature including research
publications, academic and industry reports were critically reviewed, as presented in Chapter 2
and within the introductory section of Chapters 5 through to 10. This review focused
predominantly on the development, implementation and measurement of water demand
management and dual reticulated recycled water source substitution, as well as advanced water
monitoring technologies and the measurement of end use water consumption. This literary
investigation determined the need to measure the effectiveness of water demand management
initiatives and dual reticulated recycled water supply schemes at an end use level. The
establishment of wider research objectives allowed for the formation of paper-specific
objectives and research questions to address some of the gaps identified in this phase of the
research. Two distinct phases emerged being, water end use with demand management, and dual
reticulated recycled water schemes.
11.1.2 Water end use and demand management
Phase 2 of the research investigation (Figure 3-3 and Figure 11-1) involved the adoption of
numerous research methods to investigate potable end use water consumption and the end use
water savings attributed to various water demand management initiatives. Primarily, this phase
included: establishing an understanding of residential end use study design; determining
appropriate technology for end use data collection; verifying the sample size, research region
and recruitment approach; determining the end use consumption monitoring process and data
acquisition approach; developing water stock audits and interview questions and undertaking
these with each participant in the study to validate stock and end use water consumption
behaviour in households; undertaking analysis of end use water consumption data;
development, application and analysis of a questionnaire survey to establish socio-
demographics and attitudinal perceptions surrounding water related issues; and, the recruitment,
delivery and analysis of a water demand management educational shower monitor for a sub-
sample of the research participants.
Detailed research approaches undertaken to carry out these activities are discussed in Chapters
5, 6, 7 and 8 along with the results of analysis. Chapter 5 presented the initial findings from the
Gold Coast Watersaver End Use Study based on data collected in winter 2008. This end use
data collection period occurred just a few months after drought breaking rainfall, hence
residents were generally consuming at a low level for irrigation. The chapter detailed the end
use monitoring approach along with the specifics of the project schedule for the study duration.
The average end use water consumption was recorded at 157.2 L/p/d with shower, clothes
washer and tap use dominating household end use. Irrigation was measured at 18.6 L/p/d or
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11.8% of total end use; this low use was attributed to moderate rainfall during the data
collection period and a shift in culture towards reduced garden irrigation. The end use water
consumption on average, was lower than that found in any earlier national and pacific end use
studies. A section questioning the use of volumetric or percentages for end use water
consumption modelling and forecasting argued for the use of volumetric consumption due to the
similarities and differences seen between the current and earlier end use studies. The
investigation determined that end use water consumption varied significantly between
individual households with the highest per person consumption recorded at 390 L/p/d and the
lowest at 38.4 L/p/d. It was also found that a small percentage of homes were responsible for a
large percentage of total recorded consumption for both showering and irrigation, triggering the
need to identify and effectively manage such homes water consumption. Comparative
assessment utilising basic demographic information determined that households in the higher
socioeconomic regions consumed more water per capita than those in lower socioeconomic
regions.
Chapter 6 presented the results of a mixed methods investigation into the relationship between
winter 2008 end use water consumption and socio-demographic factors. Moreover, the actual
end use water consumption savings attributed to water efficient devices was examined and pay-
back periods for water efficient shower heads, clothes washers and rainwater tanks (RWTs) was
determined. For this investigation, end use water consumption data, questionnaire survey data,
water audit and water behaviour interview data was utilised. The use of these multiple data
sources enabled validation of end use consumption and behaviours within households and
allowed for the analysis of various socio-demographic variables and the influence of water
efficient devices. It was found that socio-demographic factors such as household income,
household resident typologies, lot size and RWT ownership influenced relevant end uses. An
interesting finding was that actual water savings associated with the installation of water
efficient devices (e.g. washing machine, shower rose restrictors etc.) was higher than reported in
previous investigations with this phenomenon hypothesised to be due to the extremely low
average water consumption measured. Financial payback periods were determined with results
indicating the payback period of showerheads to be less than half a year, clothes washers to be
6.5 years and rainwater tanks to be 21 years. The payback period of RWTs at 21 years was high
due to the low consumption experienced for irrigation; further investigation on the payback
period of RWTs was recommended.
Chapter 7 presents the results of an investigation into understanding the relationship between
end use water consumption and environmental and water conservation attitudes. Again, a mixed
method design was adopted to carryout this investigation. A thorough critique of literature
occurred to develop the theoretical background pertinent to the development of environmental
Chapter 11: Conclusions, Contributions and Implications
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and water conservation attitudinal constructs. Propositions were developed and tested through a
mixed methods research approach. End use water consumption data, questionnaire survey data,
water audit and behaviour interview data were analysed using a number of statistical methods
(e.g. ANOVA, cluster analysis etc.) to achieve stated objectives. This resulted in the
determination of two constructs to measure attitudes of concern for the environment and water
conservation awareness and practice. Statistical analysis verified that resident’s fell either
within a moderate to high concern (MHC) level for environmental and water conservation
practice or a very high concern (VHC) level for the two attitudinal constructs. End use water
consumption was established for the entire research sample with a total use of 152.3 L/p/d.
Investigation on the unique end use water consumption for the MHC and VHC residential
groups determined that the VHC residents consumed significantly less water in total (128.2
L/p/d) than the MHC group of residents (169.0 L/p/d). At an end use level, VHC residents
consumed significantly less water in discretionary end uses of shower, clothes washer, tap and
irrigation when compared with the MHC residents. These results provide support for the
hypothesis that a very high level of concern for the environment and water conservation resulted
in lower water consumption across discretionary end uses. The residents within the VHC group
had a higher representation of families with slightly higher incomes, albeit this difference was
not significant.
Chapter 8 details the design and results from an investigation into the shower end use water
consumption savings attributed to an alarming visual display monitor. This investigation was
carried out to ascertain the effectiveness of an advanced resource conservation water demand
management technology on the highest end use consumption activity in residential households.
Again, a mixed methods design was adopted with both pre- and post-intervention end use water
consumption data recorded to establish the water savings attributed to the shower monitoring
device. The alarming visual display shower monitor was installed in 44 households from the
wider research sample with pre-and post-intervention data analysed through t-tests. The
reduction in average shower duration was found to be significant along with a decrease in the
rate of higher duration showers. The volume of showers was also significantly reduced post-
intervention with the median shower event falling below the stipulated 40 L per shower target.
The flow rate of showers with the alarming monitor was also significantly reduced. Resource
conservation and financial modelling determined that the payback period for the alarming
shower monitor device would be 1.65 years based on conservative cumulative water and energy
savings. Wider non-monetary benefits were also explored. This chapter concluded the water end
use and demand management phase of the study. Phase 3 focused on the dual reticulated
recycled water element of the research; details on this final research phase are presented below.
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11.1.3 Dual reticulated recycled water
Phase 3 involved the adoption of methods and analysis techniques to investigate the potable end
use water consumption savings attributed to the supply of recycled water to dual reticulated
residential households in the Pimpama Coomera (PC) region (Chapter 3). Primarily, this phase
included: the development, application and verification of a predictive recycled water uptake
model, pre-commissioning of recycled water to the PC region; measuring end use water
consumption in the PC region post-commissioning of recycled water; validating end use water
consumption in the PC region for both recycled and potable water; and developing a tool to
ascertain diurnal consumption patterns for dual and single reticulated regions. Two papers
containing pertinent literature, methods, data and results, are detailed in Chapters 9 and 10.
Chapter 9 presents the pre-commissioning end use water consumption recorded in the PC region
and details the construction of a model to predict the recycled water uptake in the PC region
post-commissioning. An overview of other residential dual reticulated recycled water regions is
discussed along with predicted and recorded bulk supplied consumption attributed to these
schemes. The literature review established that there was no end use water consumption data
recorded for residential dual reticulated recycled water supply schemes. Full detail on the
Pimpama-Coomera Dual Reticulation End Use study was presented including an overview of
the PCWF Master Plan. The mixed methods approach utilised throughout the study was adopted
to determine baseline end use water consumption data pre-commissioning. Literature and uptake
recorded in other dual reticulated regions were considered to assist in predicting potential post-
commissioning recycled water consumption. Some of the influencing parameters were: level of
water restriction, influence of customer water source preferences, price of recycled and potable
water, climatic parameters, lot sizes and the presence of a recycled water uptake awareness
campaign. The most likely predicted uptake of recycled water was determined to be 53 L/p/d or
30.5% of total end use water consumption (i.e. 30.5% A+ recycled supply and 69.5% potable
supply).
Chapter 10 deliberates the actual end use water consumption measured post-commissioning of
recycled water to the dual reticulated region of PC. Details of the pre-commissioning prediction
of recycled water uptake and the objectives of the PC Dual Reticulated End Use study are
revisited. Additional data from the summer pre-commissioning phase was presented. Again, a
mixed method research approach was followed to measure and analyse end use water
consumption post-commissioning with comparisons between the single reticulated control
group and the dual reticulated group made. Overall, it was found that post-commissioning end
use water consumption on the recycled water line was 59.1 L/p/d or 32.2% of total end use
consumption. This recorded recycled water end use consumption was slightly higher in the post-
commissioning data collection phases primarily due to increases in toilet and leakage
Chapter 11: Conclusions, Contributions and Implications
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consumption. This measured used was very close to that predicted in Chapter 9. The developed
‘Diurnal’ software enabled the compilation, analysis and presentation of end use diurnal pattern
apportionment for both single and dual reticulated regions. Diurnal patterns of use in the dual
reticulated recycled water supply region were very different to those seen in the single
reticulated region. Overall, the supply of recycled water to the dual reticulated region almost
halved the peak hour potable demand when compared to the single reticulated region.
Discussion on the application of empirically determined dual reticulated end uses and diurnal
patterns of consumption for infrastructure planning concluded this chapter.
11.2 Study Contributions
Water demand management initiatives and source substitution measures have been developed
and implemented throughout Australia and world. While the planning and application of such
water security options is widespread, the measurement and verification of the actual water
savings attributed to such initiatives is limited. Furthermore, end use investigations to verify the
potable water savings resulting from the introduction of residential dual reticulated recycled
water has not been reported in national or international literature. With this in mind, the herein
described research was carried out with a view to collect actual end use water consumption data
to support these empirical investigations. Contributions to the existing body of knowledge along
with implications for the urban water planning and management field are outlined in the
following sections.
11.2.1 Contributions to existing body of knowledge
Undeniably, the integrated water resource management field is well developed with
methodologies and application well documented. However, the measurement and validation of
the total and end use water consumption savings attributed with the application of water demand
management and source substitution measures is limited. Such end use data is necessary to
validate water resource planning and modelling assumptions. Moreover, no statistically
significant end use study has occurred in Queensland nor has an investigation into the
effectiveness of water efficient devices and the influence of socio-demographics on
consumption. An understanding of the relationship and influence of residential attitudes on
internal end use water consumption categories was another link missing within the reported
literature. Additionally, no investigation revealing an end use consumption breakdown for dual
reticulated recycled water schemes could be sourced in worldwide literature.
This study utilised a mixed method research approach to investigate the above mentioned
research gaps. The approach enabled the determination of end use water consumption for single
and dual reticulated households in the Gold Coast, along with the measurement of end use water
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consumption savings related to water efficient devices, educational prompt devices, positive
environmental and water conservation attitudes and the application of dual reticulation for
residential use. Specific contributions to the current body of knowledge are elaborated:
The research provided water consumption volumes and percentages for all residential
end uses within both single and dual reticulated regions for the Gold Coast City. Data
collected covered winter and summer seasons, for pre- and post-commissioning of
recycled water. End use studies with greater scope and frequency are highly encouraged
and required (Giurco et al., 2008a; Schlarfrig, 2008). The acquisition of such data is
important for daily demand forecasting and in the refinement of the planning and
management of water demand and supply for the Gold Coast and other regions across
Australia (Gato, 2006). Internal end use consumption volumes remained similar
throughout the research duration while irrigation altered dramatically with climatic
variables. The use of volumetric consumption for forecasting and planning was reported
as preferential to the use of traditional percentages.
Empirical end use water consumption data was ascertained for water efficient
showerheads and clothes washers. Only one other investigation of this nature has been
reported in Australia (Roberts, 2005) with results differing substantially due to higher
total consumption in the 2005 study and the ongoing advances in water efficiency
technologies. Payback periods for water efficient showerheads and clothes washers
were less than half a year and 6.5 years respectively. The variation in end use irrigation
consumption between those households with or without rainwater tanks was also
examined with statistically significant savings reported albeit payback periods being
high.
The influence of environmental and water conservation attitudes on end use water
consumption was established. While, the connection betweens attitudes and water
consumption behaviour had previously been established, an empirical study revealing
actual end use consumption data to measure attitudes, had not been carried out
(Nancarrow et al., 1996; Hassell and Cary, 2007). Attitudes of very high concern for the
environment and water conservation were found to significantly reduce total and
discretionary end use water consumption volumes. Residents with moderate concern for
the environment and water conservation consumed significantly more total and
discretionary end use water than those with very high concern. The results from this
investigation support the ongoing communication of demand management awareness
messages to influence positive environmental and water conservation attitudes, which
will in turn, result in reduced water consumption.
The study determined that showering was one of the highest end uses within homes;
hence methods to reduce this behaviourally influenced end use were researched. An
investigation into the potential end use water savings of a resource consumption display
Chapter 11: Conclusions, Contributions and Implications
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monitor which prompts users to end a shower a set volume of water used was a first of
its kind reported in the literature. The introduction of this resource awareness device
resulted in significant reductions in shower duration, volume and flow rates. The
payback period for the awareness device calculated from water and energy savings to
the household was just 1.65 years. This investigation promotes the merits of introducing
self awareness devices within homes to assist in reducing resource consumption,
ultimately helping to reduce urban ecological footprints.
There are numerous residential dual reticulated recycled water supply schemes within
Australia with each scheme being premised on engineering estimates of recycled water
uptake using a range of assumptions. No end use water consumption investigation has
been undertaken in a residential dual reticulated recycled water supply region (WSAA,
2002). End use data was captured both pre- and post-commissioning of recycled water
to the sampled households in the PC region, a smaller sample within a traditional single
reticulated region was also retained as the control group. Pre-commissioning data was
combined with influencing factors determined from literature to establish a predictive
model for the uptake of recycled water in the PC region. Monitored post-commissioning
recycled end use water consumption was slightly higher than that predicted with toilet,
leakage and irrigation increasing slightly due to the lack of water
restriction/conservation messages and climatic factors. Diurnal patterns for both dual
and single reticulated residential supply systems were determined at an end use level
with average daily demand patterns differing significantly between the two supply
schemes. The single reticulated region demonstrated trends seen previously for these
traditional schemes with the highest peak in the morning and another smaller peak in
the evening. The dual reticulated region had a much lower potable supply morning
peak, inclining more gradually when compared to the single reticulated region.
Moreover, the evening peak was higher than the morning peak with the key contributor
being recycled irrigation consumption. The variation in hourly end use demand seen in
the PC dual reticulated region, when compared to a single reticulated region supports
the need to undertake end use water consumption analysis to improve forecasting
estimates for these diversified supply schemes.
11.2.2 Implications for water planning and management
Along with an array of theoretical contributions, this study provides numerous practical
applications for the water planning and management industry. Almost all data that was
collected, analysed and complied throughout this research journey can be utilised to improve
water services planning, modelling and forecasting, as well as to support water demand
management and source substitution as effective urban water resources management initiatives.
Particular implications to the water planning and management industry are as follows:
Domestic End Use Investigation: WDM and Dual Reticulation, R.M. Willis (2010)
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End use water consumption data acquired from the Gold Coast region can be used to
update and verify planning and modelling assumptions utilised in documentation, such
as the desired standards of service, and for accurate modelling of water use and waste
water discharges. The obtainment of actual diurnal patterns of consumption is also
essential for the verification of, and use in, planning documentation. This data is also
extremely useful for understanding the elements and factors that influence residential
demand hence assisting to improve residential demand forecasting.
Validation of real end use water savings and payback periods attributed to water
efficient devices, rainwater tanks and resource consumption display shower monitor
devices provides evidence to strengthen the application of water demand management
initiatives. The results from this study significantly support the introduction and use of
water efficient showerheads and clothes washers and promotes the application of
resource awareness devices to reduce end use and total household water consumption.
Moreover, results provide water demand management professionals with an
understanding on where educational programs should be targeted to obtain the highest
effective household water savings. Findings also support the continuation of awareness
and education programs to instil sustainable water consumption and environmental
attitudes. Learning’s are applicable for consumption reduction for other resources i.e.
energy, waste or materials and for use across commercial and industrial sectors.
Analysing consumption in a dual reticulated recycled water region provided world first
data on end uses and diurnal patterns in these unique source substitution areas. End use
data determined that, as predicted, toilet and leakage remains relatively consistent
throughout the year, while irrigation is strongly impacted by climatic conditions and the
promotion of recycled water uptake. Total potable water consumption was reduced by
37.2% through the introduction of recycled water. Diurnal patterns showed that the peak
hour demand on the potable water supply system is almost halved through the supply of
recycled water. The acquisition of such data is invaluable for water services planning,
and the forecasting and modelling of supply and demand within water supply regions.
Furthermore, such data assists in the verification of urban water planning assumptions
such as those presented in the desired standards of service reports.
11.3 Study Limitations and Future Research Directions
This study included a variety of methods, numerous rigorous analysis procedures and produced
an array of theoretical and practical results for immediate application. Despite this, there were
several limitations identified. These limitations together with recommendations for future
research directions are as follows:
Chapter 11: Conclusions, Contributions and Implications
- 255 -
The study investigated residential end use water consumption in single detached
households on the Gold Coast. Additional monitoring of dual lot dwellings, townhouses
and units could be carried out to compare with indoor end uses found in single detached
dwellings. Further end use research throughout other regions in Queensland is
recommended. Such a study is underway, with the Urban Water Security Alliance
commissioning an SEQ wide study to investigate differences in location specific end
use consumption.
Due to the delay in the commissioning of recycled water to the PC region, the winter
end use data log was not carried out. End use water consumption data collection and
analysis in the winter period will assist to further verify low and high use seasons.
Collection of end use data over a longitudinal basis in line with climatic trends will also
assist in verifying the exact impact of climate on end use consumption in the Gold
Coast.
Additional investigations on the long term effectiveness of the educational shower
monitor prompt devices are necessary to determine if water savings would continue in
the long term. The use of a larger sample size would also assist in verifying results and
determining appropriate shower volumes for different demographic subsets. The
application of questionnaires or interviews to better understand perceptions of the
device and its affect on behaviour change would provide interesting outcomes for
sustainable consumption behaviour theory. Furthermore, the monitoring of energy use
attributed to end use water consumption in the home would verify and strengthen the
predictions on energy savings and subsequently the payback period of such devices.
Measuring and understanding the energy savings related to water demand management
initiatives will promote the uptake of these measures. The water energy nexus is an area
which requires significant applied research attention, especially with the need to move
towards sustainable resource consumption.
The development of a knowledge base containing sustainable urban water management
information to inform the most appropriate initiatives to implement for both short and
long term water security would greatly assist water management in Australia. National
policy formulation would result from the development of such a platform.
11.4 Closure
An explanatory mixed method research design was carried out to determine end use water
consumption data for single and dual reticulated, Gold Coast single detached residential
households. More specifically, the study determined the potable water savings attributed to
water demand management initiatives including efficient and resource consumption awareness
prompt devices; the relationship between environmental and water conservation awareness
Domestic End Use Investigation: WDM and Dual Reticulation, R.M. Willis (2010)
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attitudes on end use water consumption; and the end use consumption in a dual reticulated
supply region pre- and post-commissioning of recycled water. An introduction, overarching
literature review, research method and situational context explanation is presented in the first
four chapters of the dissertation. These chapters form the foundation for the research.
This dissertation is predominantly composed of peer-reviewed papers related to the various
research objectives contained within the two distinct phases of the project namely, water end
use and demand management; and dual reticulated recycled water end uses. Chapters five
through to ten are reformatted journal manuscripts (published, accepted or submitted) which
include their own background, literature review, research method, data analysis, results and
discussion. Finally, this dissertation concluded with a summary of the research contributions,
implications and limitations as well as proposed recommendations for future research in the
sustainable urban water management field.
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Appendices
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Appendix A Demographic Investigation of Gold Coast
Regions
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Community Profile - http://203.84.234.220/Profile/GoldCoast/Default.aspx?id=292
Parkwood/Arundel - consider uni students
Ashmore/Benowa - consider older population and more people owning their homes)
Molendinar – consider govt owner properties and couples with older kids
Carrara – has significantly lower income
Mudgeeraba – slightly lower income and more people purchasing but not significant
Pimpama – Coomera
More people per household than average
More renters than people purchasing
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High incomes / High households of parents with young kids
Skewed towards younger population - parents with young kids
Unusual that there is a proportion of high incomes combined with a high proportion of renters. Possible
that people are renting in Pimpama Coomera until they build or buy elsewhere. Or maybe new generation
is investing their money elsewhere (other than in their own homes)???
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Parkwood – Arundel (compared to Pimpama Coomera)
More people per household
Slightly people purchasing than renting
Slightly lower income
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More people aged 12-24, maybe due to uni being close by
Ashmore – Benowa (compared to Pimpama Coomera)
Slightly less people per household More people purchasing/owning than renting
Lower income More one parent families
Older population
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Molendinar (compared to Pimpama Coomera)
Slightly more people per household
Similar pattern in purchasing vs. renting but higher level of Govt. owned properties
Lower income / Couples with older children
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Older kids – higher proportion of 12 to 24 yr olds.
Carrara – Merrimac (compared to Pimpama Coomera)
Slightly less people per household / Similar pattern of renting vs. purchasing
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Lower income / Less number of couples with kids
Similar
Mudgeeraba (compared to Pimpama Coomera)
Slightly more people per household / More people purchasing then renting
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Lower income / Similar
Similar
Helensvale
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Elanora
Edens Landing – Holmview
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Oxenford – Maudsland
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Appendix B Participant recruitment letter
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Appendix C Frequently asked questions
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Appendix D Participant consent form
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Appendix E Water audit and interview
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Appendix F Questionnaire Survey
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Appendices
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Appendix G Letter for questionnaire survey