melbourne's water situation: the opportunity for diverse solutions
DESCRIPTION
A 2009 report that presents scenarios of Melbourne’s water shortage levels based on supply flows (inflows) and demand (population and per capita use) to give a broad-brush account of long-term water supply. This analysis looks only at broad likely trends.TRANSCRIPT
7/14/2019 Melbourne's Water Situation: The opportunity for diverse solutions
http://slidepdf.com/reader/full/melbournes-water-situation-the-opportunity-for-diverse-solutions 1/35
Melbourne’s water situationThe opportunity for diverse solutions
Philip Wallis, Bob Birrell, Dave Griggs,
Ernest Healy, John Langford, Janet Stanley
Report 09/2
November 2009
7/14/2019 Melbourne's Water Situation: The opportunity for diverse solutions
http://slidepdf.com/reader/full/melbournes-water-situation-the-opportunity-for-diverse-solutions 2/35
7/14/2019 Melbourne's Water Situation: The opportunity for diverse solutions
http://slidepdf.com/reader/full/melbournes-water-situation-the-opportunity-for-diverse-solutions 3/35
Melbourne’s Water Situation
The opportunity for diverse
solutions
REPORT 09/2
November 2009
7/14/2019 Melbourne's Water Situation: The opportunity for diverse solutions
http://slidepdf.com/reader/full/melbournes-water-situation-the-opportunity-for-diverse-solutions 4/35
Page ii
Produced by the Monash Sustainability Institute The Monash Sustainability Institute (MSI) delivers solutions to key sustainability challenges through
research, education and action. For government, business and community organisations, MSI is a
gateway to the extensive and varied expertise in sustainability research and practice across Monash‟s
faculties and research institutes. Our research covers the many areas of water, energy, climate
change, transport and urban design and biodiversity as solutions are found in a cross-disciplinary
approach of the social sciences, economics, law, health, science and engineering.
November 2009
ISBN: 978-0-9806387-1-4
© Monash Sustainability Institute, 2009 Authors:
Philip Wallis
Bob Birrell
Dave Griggs
Ernest Healy
John Langford
Janet Stanley
To be cited as: Wallis, P., Birrell, R., Griggs, D., Healy, E., Langford, J., and Stanley, J. (2009)
„Melbourne‟s water situation: the opportunity for diverse solutions.‟ Monash Sustainability Institute
Report 09/2 , Melbourne.
Monash Sustainability Institute
Building 74, Clayton Campus
Wellington Road, Clayton
Monash University
VIC 3800 Australia
Tel: +61 3 990 59323
Fax number +61 3 990 59348
Email: [email protected]
DISCLAIMER:
Monash University disclaims all liability for any error, loss or consequence which may arise from you
relying on any information in this publication.
7/14/2019 Melbourne's Water Situation: The opportunity for diverse solutions
http://slidepdf.com/reader/full/melbournes-water-situation-the-opportunity-for-diverse-solutions 5/35
Page iii
Contents
Glossary .............................................................................................................................. iv Water measurements .......................................................................................................... iv 1. Summary ....................................................................................................................... 1
1.1. Overview ................................................................................................................. 1 1.2. Major points ............................................................................................................. 2 1.3. Major recommendations .......................................................................................... 3
2. Introduction ................................................................................................................... 4 2.1. Present and future planned source of Melbourne‟s water ........................................ 4 2.2. Planning for Melbourne‟s water ................................................................................ 5 2.3. Observed storage levels .......................................................................................... 7
3. Short-term water situation ......................................................................................... 10 3.1. Department of Sustainability and Environment 2008 analysis ................................ 10 3.2. The outlook for 2009/10 ......................................................................................... 11
4. Long-term demand and supply issues ...................................................................... 12 4.1. Demand scenarios ................................................................................................. 13
4.1.1.
Population estimates ...................................................................................... 14
4.1.2. Total water use to 2051 .................................................................................. 14 4.2. Water supply .......................................................................................................... 15 4.3. Supply-demand projections ................................................................................... 16
4.3.1. Other considerations and assumptions ........................................................... 17 4.3.2. Supply-demand projection: medium average inflows (380 GL) ....................... 18 4.3.3. Supply-demand projection: low average inflows (300 GL)............................... 19 4.3.4. Implications of long-term supply-demand projections ...................................... 20
5. The long term outlook ................................................................................................ 20 5.1. Supply-oriented options ......................................................................................... 21 5.2. Demand-oriented options....................................................................................... 22
5.2.1. Criteria for managing the demand for water .................................................... 22 5.2.2. Reduction in rate of population growth ............................................................ 23 5.2.3. Tightening water use restrictions .................................................................... 23 5.2.4. Price increases ............................................................................................... 24 5.2.5. Appeals for conservation ................................................................................ 24 5.2.6. Enforced efficiencies....................................................................................... 25 5.2.7. Knowledge dissemination and social marketing .............................................. 26 5.2.8. WaterSmart .................................................................................................... 26 5.2.9. Smart metering ............................................................................................... 26 5.2.10. Assistance to low income households............................................................. 27
6.
Conclusions ................................................................................................................ 27
7. References .................................................................................................................. 28 Appendix A ......................................................................................................................... 29
7/14/2019 Melbourne's Water Situation: The opportunity for diverse solutions
http://slidepdf.com/reader/full/melbournes-water-situation-the-opportunity-for-diverse-solutions 6/35
Page iv
Glossary
Desalination Production of potable water from seawater by removing salt
Full supply level Total capacity of Melbourne‟s supply storages (1,810 GL in July
2009)
Inflows Water inputs from streams feeding major water harvestingstorages
Potable water Water fit for human consumption
Southern Oscillation
Index
A measure of seasonal fluctuations in air pressure in tropical
pacific and has important consequences for weather around the
globe
TFR Total fertility rate
Trigger levels Water storage level at which a change to, or between, water
restrictions is recommended
Water measurements
1 gigalitre (GL) = 1,000 megalitres or 1,000,000,000 litres
1 megalitre (ML) = 1,000,000 litres (L)
1 US gallon = 3.78 litres
7/14/2019 Melbourne's Water Situation: The opportunity for diverse solutions
http://slidepdf.com/reader/full/melbournes-water-situation-the-opportunity-for-diverse-solutions 7/35
Page 1
1. Summary
1.1. Overview
Drier and warmer climatic conditions are predicted for south east Australia. The frequency
and magnitude of rainfall events, particularly in late autumn is already exhibiting signs of a
shift to a drier climate. Late Autumn rainfall (Figure 1) has decreased over south east
Australia in recent years (Cai and Cowan, 2008a). A recent climate report presented a range
of greenhouse gas emission scenarios, based on IPCC methodology, and projected warmer
and drier climatic conditions for south eastern Australia (CSIRO, 2007). As a consequence,
increased frequency of drought and increased fire weather risk are predicted. Regional
drying appears to have been occurring for over 40 years (Cai and Cowan, 2008b).
Figure 1 Late Autumn rainfall has
decreased over south east
Australia in recent years (Source:
adapted after Cai and Cowan,
2008a)
The south west of Western Australia has already experienced a step change to a drier
climate that has persisted for over 30 years, which is consistent with the model predictions
that the mid latitude climatic systems that bring rain to southern Australia will shift south
reducing the rainfall. The possibility that south east Australia is experiencing a step-change
to a drier climate has substantial implications for water availability and highlights the need to
insure against this.
This report presents a review of the future levels of Melbourne‟s water supplies in the contextof the latest levels of water supply and demand (as of November 2009). It projects water
demand based on various levels of per capita usage and population growth in Melbourne.
The long-term demand and supply outlook to 2051 is projected, encompassing the water
from the desalination plant which becomes operational in 2012. We explore the implications
of various supply outcomes, including a continuation of low rainfall conditions and various
water usage scenarios.
Options for reducing the demand for water are canvassed, including incentives to implement
efficiency, pricing adjustments, public campaigns, smart operating systems, and by limiting
population growth. These options need to be widely discussed with a view to large scale
implementation, in a context where the public is aware of the seriousness of the water
storage outlook. Options and their costs and benefits need to be more clearly defined and
provided to the public so the choices being made are clear.
7/14/2019 Melbourne's Water Situation: The opportunity for diverse solutions
http://slidepdf.com/reader/full/melbournes-water-situation-the-opportunity-for-diverse-solutions 8/35
Page 2
1.2. Major points
1. In handling the present emergency, aspirational environmental flows have been
foregone. Environmental flows in rivers have been reduced below sustainable levels
such as will result in long term loss of biodiversity and damage to ecosystems if these
were to continue or decline further.
2. The desalination plant and the Sugarloaf pipeline will supply Melbourne‟s medium
term water needs, thus it is crucial that these become operational as scheduled. At
this stage, there are no alternative water supply options that would provide the
amount of water necessary in the short-term (>200 GL/year by 2012).
3. In 10 to 12 years, with the present climate and population trends, storage levels will
again be on a downwards trend if there is a return to high per capita water use. With
the current high population projection and a return to high per capita water use after
the desalination plant comes on stream, storages could peak before 2020 under
medium inflows, or earlier under low inflows unless an ambitious water conservation
program is maintained. In the longer term if high population growth continues,additional supply will be necessary, despite low per capita water use. For example,
under current ABS population projections (Melbourne reaches 6.6 million by 2051)
and low per capita water demand, the storages risk being virtually empty by 2051.
4. Efforts in efficiency and demand management, as well as the effect of water
restrictions, have reduced total per capita water consumption in Melbourne from 500
L/p/day in the 80s to just over 250 L/p/day at present.
5. The recent change in water usage in Melbourne which now prevents or severely
restricts the watering of plants will alter the appearance and external environment of
Melbourne, previously marketed as a garden city. There needs to be open, informed
discussion about the choices that are being made in relation to this.
7/14/2019 Melbourne's Water Situation: The opportunity for diverse solutions
http://slidepdf.com/reader/full/melbournes-water-situation-the-opportunity-for-diverse-solutions 9/35
Page 3
1.3. Major recommendations
1. Sustainable environmental flows to the Yarra River must be restored and maintained
once the security of water storages is increased when the desalination plant and
Sugarloaf pipeline become operational.
2. Water efficiency and demand management programs should be maintained inperpetuity. A comprehensive program for demand management should be developed
with a review of cost effectiveness and estimates of water saved, and
recommendations about a process to manage a large-scale program in this area.
3. Planning should commence for water provision for Melbourne after the next decade,
defining a sequence of options that take into account whole-of-lifecycle costs
(including energy and externalities), and should contain a mix of both centralised and
decentralised options and be planned in the context of urban design and alternative
energy sources. There should be public discussion about the effective choices that
will be made.
4. Steps should be taken by the government to inform the community and collect public
opinion about the present state of environmental flows in Victoria and current
ecological losses due to low river flows. The Victorian Government should make
available information on the flows needed to restore/maintain ecosystems.
5. Begin engaging with community perceptions of indirect potable reuse. A water
treatment facility should be constructed at the Eastern Treatment Plant to supply
industry and golf courses, with the ability to be upgraded in order to treat water to
drinking quality. Demonstrate the production of drinking quality water on a pilot scale
and engage with the public about the potential to upgrade the plant for full indirect
potable reuse.6. Introduce a range of schemes including water pricing with built in equity principles,
social marketing schemes such as a WaterSmart program, an up-scaling of the water
saving plans for business and industry.
7/14/2019 Melbourne's Water Situation: The opportunity for diverse solutions
http://slidepdf.com/reader/full/melbournes-water-situation-the-opportunity-for-diverse-solutions 10/35
Page 4
2. Introduction
2.1. Present and future planned source of Melbourne’s water
Melbourne presently relies entirely on stored water (see Figure 2). The reservoirs and
capacities are as follows:
Thomson – 1,068,000 megalitres (ML)
Cardinia – 287,000
Upper Yarra - 200,000
Sugarloaf - 96,000
Silvan – 40,000
Tarago – 37,500
Yan Yean – 30,000
Greenvale - 27,000
Maroondah – 22,000
O‟Shannassy – 3,000
Total: 1,810,500 ML
Figure 2: Melbourne’s water storages
Source: www.melbournewater.com.au/images/water_storages/wss_map_lrg.gif accessed 1
June 09.
To augment Melbourne’s water supply, additional water sources are planned:
Re-commissioning of Tarago (Connected in June 2009) – 15 GL available annually.
The Sugarloaf Pipeline – 75 GL planned for annually (under construction).
A desalination plant – 150 GL annually (planned).
Extension of a suspension of environmental flows for the Yarra River and Thomson
River until July 2010 (Ker 2009a).
7/14/2019 Melbourne's Water Situation: The opportunity for diverse solutions
http://slidepdf.com/reader/full/melbournes-water-situation-the-opportunity-for-diverse-solutions 11/35
Page 5
2.2. Planning for Melbourne’s water
Melbourne is currently experiencing a water crisis. Since 1996, rainfall in Melbourne‟s water
supply catchments has fallen well below the historic pattern. Between October 1996 and May
2004, the Greater Melbourne Region experienced its lowest rainfall on record in comparison
with all other periods of similar duration (CSIRO 2005: 3). As Figure 3 shows, the result has
been a sustained fall in average inflows to Melbourne‟s storages since 1997 to around just
377 GL per year. By comparison, the average inflow over nearly one hundred years was 608
GL per year (Figure 3).
Figure 3: Melbourne storage inflows 1913 to 2008 (calendar years)
Source: Modified after “Augmentation of the Melbourne Water Supply System”, DSE 2008, p. 5
Five official inquiries into Melbourne‟s water supply have taken place over the last decade.
The first was prepared by the Water Resources Strategy Committee for the Melbourne area,
established by the Victorian Government in October 2000. This inquiry pre-dated the water
crisis, with the Committee‟s recommended strategy stating that with significant demand
reduction by 2050, Melbourne would require only 571 GL per year from the catchmentsinstead of a projected 659 GL per year without demand management. This represented a
decrease in per capita usage from the 1990s average of 423 L/p/day down to 327 L/p/day in
2050. The population assumption was that there would be an increase from 3.5 million in
2001 to a projected 4.6 million by 2050 (Water Resources Strategy Committee, 2002).
Overall, the strategy highlighted increased climate variability (but not the dramatic step-down
that was to come), increasing population (but underestimated the increase by approximately
2 million people by 2050) and a preference for demand reduction over supply increase. In the
meantime, the Victorian Government‟s White Paper, Our Water Our Future: Securing Our
Water Future Together , was released in 2004 and set out key water policy. This policy was
based on (1) balancing water supply and demand (2) reducing water consumption (3) usingalternative supplies including recycled water, grey water and stormwater and (4) using
existing water supplies more effectively by interconnecting water systems.
7/14/2019 Melbourne's Water Situation: The opportunity for diverse solutions
http://slidepdf.com/reader/full/melbournes-water-situation-the-opportunity-for-diverse-solutions 12/35
Page 6
The second inquiry was a study of the implications of climate change on Melbourne‟s wa ter
supplies, conducted by the CSIRO and Melbourne Water and published in 2005. A major
finding was that streamflows would be reduced by as much as 7% to 35% by 2050, with a
mid-range reduction of 20% (CSIRO 2005: v).
The third inquiry, the Central Region Sustainable Water Strategy, was published as a
discussion paper in October 2005, a draft strategy in April 2006 and as a final report in
October 2006 and defined a water strategy for Melbourne and its surrounds, including West
Gippsland, Port Phillip and Westernport (Victorian Government 2006a). This strategy was
consistent with earlier policies of water conservation and efficiency. However, as the strategy
was based on the assumption that low inflows would continue, large scale augmentation of
water supplies, namely an upgrade of the Eastern Treatment Plant to produce recycled
water, was proposed.
By the time the fourth inquiry commissioned by the Victorian Government, the Water Supply-
Demand Strategy for Melbourne, reported in late 2006, the supply situation had deteriorated
and water restrictions had already been introduced (Victorian Government 2006b). This
report was not confident that the historic rainfall pattern would return and that the post-1996drought was part of natural climate variability. It predicted a partial return to the historic
pattern of rainfall (Victorian Government 2006b). Nevertheless, their core supply assumption,
which is represented by the „long-term average inflows‟ line shown in Figure 4, was that there
would be a gradual decline in inflows to Melbourne‟s water catchments, which reflected the
judgement of the 2005 CSIRO study.
Figure 4: Baseline supply-demand forecast
Source: Melbourne Water, Water supply-demand strategy for Melbourne, 2006-2055, Victorian
Government 2006b: 25.
The baseline demand assumptions incorporated into Figure 4 were that per capita demand
would remain at the level prior to the introduction of water restrict ions and that Melbourne‟s
population (as with the first inquiry) would increase to 4.6 million by 2050. As Figure 4
indicates, under the long-term average inflow assumption, demand for water would exceed
supply by around 2020. At the time the report from this fourth inquiry was being prepared,
Melbourne catchments were experiencing record low inflows during the winter and spring of
7/14/2019 Melbourne's Water Situation: The opportunity for diverse solutions
http://slidepdf.com/reader/full/melbournes-water-situation-the-opportunity-for-diverse-solutions 13/35
Page 7
2006 (an El Niño year). This prompted the authors to include a „low inflows‟ scenario (Figure
4), which assumed that there would not even be a partial return to the historic rainfall pattern.
Instead, the inflow would stabilise at the average of the period of 1997 to 2005, or about 385
GL per annum. Should this outlook come to pass, it was obvious that Melbourne‟s storages
would rapidly be depleted. In such circumstances, the report recommended examining a
range of water conservation measures as well as supply augmentation possibilities,
suggesting stormwater, groundwater, recycled water and desalinated seawater as possibleoptions (Victorian Government 2006b: 41). However, the inquiry report was required to work
within the framework of „no new dams for Melbourne‟; „water cannot be traded between
Melbourne and northern Victoria‟; and „no water recycling for drinking purposes in the short
to medium term‟ (Victorian Government 2006b, 3).
After a year of some of the lowest rainfall recorded in Melbourne, an update on the Victorian
Government‟s Our Water Our Future 2004 water policy, entitled Our Water Our Future: the
Next Stage of the Government’s Water Plan, was released in June 2007 and outlined a
series of new major water projects for Victoria (DSE 2007a). These included a desalination
plant for Melbourne, irrigation modernisation in Victoria‟s North, a pipeline (the Sugarloaf
Pipeline) linking water supplies from the Goulburn River to Melbourne, an upgrade of the
Eastern Treatment Plant for provide recycled water and new water conservation programs
(DSE 2007a). In total, 240 GL of new water supplies would be delivered to Melbourne by
2011 via desalination (150 GL), irrigation modernisation/Sugarloaf Pipeline (75 GL) and
recommissioning of the Tarago Reservoir (15 GL). A 2008 report by DSE described in more
detail how the planned augmentations would secure Melbourne‟s water supply and
emphasised the critical need for the desalination plant for Melbourne‟s supplies in the short-
term (DSE 2008).
A fifth inquiry into Melbourne‟s future water supply was conducted by the Environment and
Natural Resources Committee of the Parliament of Victoria. In his foreword to the report,
committee chair the Hon John Pandazopoulos remarked that “by 2036 Melbourne‟s water
supplies will require further augmentation” (ENRC 2009: xvii) , in addition to the
augmentations outlined in the 2007 plan. The inquiry report, released in June 2009, outlines
the recommendations of the committee, including an emphasis on mandatory water efficient
fixtures, a sustainability rating system that includes water efficiency, strong water recycling
targets and mandatory dual-pipe systems in new developments. However, the report utilised
the same out-of-date catchment inflow projections used in the 2006 supply-demand inquiry
and the 2008 DSE report.
2.3. Observed storage levels
The projected water storage levels reported in the 2006 supply-demand inquiry have since
been overtaken by events. The year 2006 resulted in the lowest annual inflow into the
catchments servicing Melbourne‟s dams for the 83 years of comparable records. Only 165
GL flowed into Melbourne‟s storages in the 2006 calendar year. As a result, in just one year
the water stored in the catchments fell from around 60% of capacity in December 2005 to
40% in December 2006, followed by a further decline to 30% by July 2007 (Figure 5).
7/14/2019 Melbourne's Water Situation: The opportunity for diverse solutions
http://slidepdf.com/reader/full/melbournes-water-situation-the-opportunity-for-diverse-solutions 14/35
Page 8
Figure 5: Observed water storage levels for Melbourne, July 1996 to November 2009. Observed
Southern Oscillation Index (SOI) July 1996 to October 2009
-40
-30
-20
-10
0
10
20
30
40
0
10
20
30
40
50
60
70
80
90
100
J ul y / 1 9 9 6
J ul y / 1 9 9 7
J ul y / 1 9 9 8
J ul y / 1 9 9 9
J ul y / 2 0 0 0
J ul y / 2 0 0 1
J ul y / 2 0 0 2
J ul y / 2 0 0 3
J ul y / 2 0 0 4
J ul y / 2 0 0 5
J ul y / 2 0 0 6
J ul y / 2 0 0 7
J ul y / 2 0 0 8
J ul y / 2 0 0 9
J ul y / 2 0 1 0
J ul y / 2 0 1 1
J ul y / 2 0 1 2
S t o r a g e v o l u m e / %
SOI July 1996 - November 2009
T a r a g o r e c o n n e c t e d
( 2 4 t h J u n e 2 0 0 9 )
N o r t h - S o u t h P i p e l i n e
( F e b r u
a r y 2 0 1 0 )
D e s a l i n a t i o n P l a n t
( D e c e
m b e r 2 0 1 1 )
Sources: Weekly water report archives, www.melbournewater.com.au accessed 16 November
2009; Bureau of Meteorology SOI archives, www.bom.gov.au accessed 16 November 2009.
Three periods of particularly low inflows in 1997/98, 2002/03 and 2006/07, played a major
role in the decline in storage levels detailed in Figure 5. These periods corresponded to El
Niño events, as indicated by negative values of the Southern Oscillation Index (SOI). The
SOI is derived from the seasonal fluctuations in air pressure in tropical pacific and has
important consequences for weather around the globe. An El Niño event causes rainfall as
warm water flows eastward and is associated with flooding in Peru and drought in Indonesia
and Australia. Current values of the SOI are negative and Central Pacific Ocean
temperatures are the highest seen since the El Niño of 2002 (BOM 2009a).
The Indian Ocean Dipole (IOD) is also thought to influence rainfall patterns over Australia.
Occurrences of positive values of the IOD are associated with below average winter-springrainfall, whereas negative IOD values are associated with above average winter-spring
rainfall (BOM 2009b). Currently, the IOD is positive and is predicted to remain so until June
2010 (BOM 2009c).
Melbourne‟s water usage has reduced significantly in recent years, as shown in Table 1. A
significant reduction in water demand has been achieved since 2002 through a combination
of water conservation and restrictions, which were prioritized in most of the strategy
documents referred to above.
7/14/2019 Melbourne's Water Situation: The opportunity for diverse solutions
http://slidepdf.com/reader/full/melbournes-water-situation-the-opportunity-for-diverse-solutions 15/35
Page 9
Table 1: Water use in Melbourne, showing July 1st
storage volume, percentage change in water
storages, annual usage of water and annual inflows
Year* Storagevolume(%)
Annualchange(%)
Annualusage(GL; % of 1990’s)
Annualinflows(GL)
Per capitadomestic useL/p/day (annAvg.)
2008/09 26.0 -3.6 370 (-26%) 285 1532007/08 29.6 -2.3 381 (-24%) 363 1612006/07 29.7 -15.9 410 (-18%) 165 1772005/06 48.0 -4.3 443 (-11%) 362 1952004/05 52.2 +3.2 440 (-12%) 492 2002003/04 48.9 +8.4 439 (-12%) 534 1992002/03 40.5 -10.0 479 (-4%) 303 2202001/02 50.5 +1.4 473 | 446 2172000/01 49.3 -1.3 505 | 497 2391999/00 50.0 -9.6 500 | Average. 366 2401998/99 58.4 -1.1 487 | 500 GL/year 442 2371997/98 59.5 -19.5 517 | 250 254
1996/97 76.1 -8.0 510 | 665 253Sources: DSE 2007b; Weekly water report archives, www.melbournewater.com.au
* Melbourne Water reporting year, 1st
July to 30th
June. Note: based on weekly reported data
The direct domestic component of water usage represents an average per capita daily
residential use of water during 2007-08 of around 161 litres. This is very close to the level
sought under the Victorian Government‟s recent water conservation campaign, Target 155,
which began in December 2008. This promotes direct domestic water conservation to bring
per capita consumption in Melbourne down to 155 L per person per day, which is
approximately equivalent to Stage 4 domestic restrictions. Despite consumption exceeding
155 L over the course of a hot and dry summer, the program appears to have been
successful to date, with Melburnians saving eight billion litres so far during 2009, compared
to 2008.
The decision to implement domestic water restrictions is made by the Minister for Water on
advice from the water industry and in accordance with the Drought Response Plan. Trigger
levels or changes between water restriction stages reflect the seasonality of inflows and
water demand, except for Stage 4 restrictions, which are based on proximity to minimum
operating storage levels (see table in Appendix A for Trigger levels). The Victorian
Government has delayed moving to Stage 4 domestic restrictions until November 2009,
instead hoping that Target 155 will achieve the same reduction in demand. After aboveaverage rainfall in September 2009, it would seem that Stage 4 restrictions will be avoided
for the foreseeable future.
Each stage imposes stronger restrictions on direct domestic water use, particularly for
domestic outdoor water use. The permanent water saving measures implemented in March
2005 require the use of trigger nozzles on hoses for outdoor watering and prohibit any hosing
down of paved areas. They also put conditions on filling new swimming pools and operating
rules for manual and automatic watering systems. Stage 4 requires no outdoor water use at
any time, whereas limited outdoor watering is allowed for Stages 1 to 3a.
7/14/2019 Melbourne's Water Situation: The opportunity for diverse solutions
http://slidepdf.com/reader/full/melbournes-water-situation-the-opportunity-for-diverse-solutions 16/35
Page 10
The seasonal pattern of consumption and the overall trend in total usage of water since July
1999 can be observed in Figure 6, plotted against a population increase from 3.4 million
people to 3.9 million people over the same time period.
Figure 6: Total weekly water demand (GL) and population growth for Melbourne, 1999 to 2009
3.0
3.2
3.4
3.6
3.8
4.0
0
2000
4000
6000
8000
10000
12000
14000
16000
J ul y / 1 9 9 9
J ul y / 2 0 0 0
J ul y / 2 0 0 1
J ul y / 2 0 0 2
J ul y / 2 0 0 3
J ul y / 2 0 0 4
J ul y / 2 0 0 5
J ul y / 2 0 0 6
J ul y / 2 0 0 7
J ul y / 2 0 0 8
J ul y / 2 0 0 9
J ul y / 2 0 1 0
P o p u l a t i o n / m i l l i o n p e o p l e
T o t a l w
e e k l y w a t e r d e m a n d / G L
Weekly water demand Population Pro jected population
Source: Weekly water report archives, www.melbournewater.com.au accessed 17 November
2009; Australian Bureau of Statistics, regional population growth Australia (cat. 3218.0).
3. Short-term water situation
3.1. Department of Sustainability and Environment 2008 analysis
The Department of Sustainability and Environment (DSE) released a report titled
Augmentation of the Melbourne Water Supply System, Analysis of Potential System
Behaviour in August 2008 that presented an analysis of the response of Melbourne‟s water
supply system to planned augmentations (DSE 2008). This analysis took into account
scenarios of recent low inflows and projections of future water demand based on the
population growth projections assumed by the State Government.
The analyses performed by DSE considered two flow scenarios: one based on 3-year inflows
(2004/05/06) and one based on 10-year inflows (1997-2006). The 3-year scenario with the
lower inflows was constructed in a repeating sequence of 2004 (508 GL), 2005 (392 GL) and
2006 (163 GL) inflows. The average inflows in this scenario are 355 GL per year. Planned
augmentations to the water supply system were modelled to start in late 2009 with the
reconnection of the Tarago Reservoir (providing 15 GL/year in a low-flow year), followed by
the Sugarloaf Pipeline (providing 75 GL/year) in the first half of 2010 and the Desalination
Plant in late 2011 (providing 150 GL/year) (DSE 2007b). The 10-year inflow scenario is
based on 1997-2007 historical inflows and 1913-1996 inflows adjusted down by 30% toaccount for a step-change in Melbourne‟s climate, with annual inflows averaging 425 GL per
year.
7/14/2019 Melbourne's Water Situation: The opportunity for diverse solutions
http://slidepdf.com/reader/full/melbournes-water-situation-the-opportunity-for-diverse-solutions 17/35
Page 11
Since the release of the DSE analysis, an additional year of well below average inflows of
285 GL has occurred in 2008/09. Taking into account the previous two years of inflow data,
the „recent‟ average inflows over the period 1997 to 2008 was 377 GL per year. This
represents a decrease on the long-term average that is closer to 38%, rather than the 30%
decrease as referred to in the DSE report.
3.2. The outlook for 2009/10
In 2009, Melbourne‟s main water harvesting catchments had experienced one of the driest
starts to a year on record (Figure 7). Above average rainfall in September and enhanced
inflows through October boosted water storages back up to 38.1% of capacity, which is
almost 5 per cent more than the same time last year (2008).
Figure 7: Victoria Rainfall deciles, 1 January to 30 June 2009.
Source: Australian Bureau of Meteorology, www.bom.gov.au accessed 12 November 2009.
7/14/2019 Melbourne's Water Situation: The opportunity for diverse solutions
http://slidepdf.com/reader/full/melbournes-water-situation-the-opportunity-for-diverse-solutions 18/35
Page 12
4. Long-term demand and supply issues
For the long-term (to 2050), the question is whether further supply augmentation measures
will be required, or whether continued demand management and efficiency measures can
achieve similar security of supply.
Water demand is a function of the number of people served and their per capita consumptionlevels. The 2002 and 2006 water inquiries cited earlier assumed that Melbourne‟s population
would increase to 4.6 million by 2050. Melbourne‟s population has surged since the early
part of this decade, primarily as a consequence of increased overseas migration, but also
because of an increase in fertility. If migration and fertility continue at the recent levels,
Melbourne will have to provide for a much larger population than was assumed in the
Victorian Government studies discussed earlier. The median-level projection of Australia‟s
population prepared by the Australian Bureau of Statistics and published in August 2008
assumed that recent fertility and migration trends will continue. In these circumstances
Melbourne‟s population will grow from 3.7 million in 2006 to 6.5 million in 2050 (ABS 2008).
Should this projected outcome occur, water will have to be provided for an additional 2.8
million people by 2050 rather than the one million assumed in the earlier reports. The scale
of the additional water needed will depend on the water consumption patterns of Melbourne
residents. During the last few years households and municipalities have largely had to forgo
their attachment to lawns, gardens, playing fields, street trees and parks which require
regular watering.
Additionally, environmental flows in rivers have been reduced below long term sustainable
levels such as will result in long term loss of biodiversity and ecosystems if they were to
continue. In the case of the Yarra, the mean annual flow in the reach below the Upper Yarra
Dam has been reduced by 95% of the original flow (Sinclair, Knight, Merz, 2005: 7). Theconsequence is that the channel below the dam has been reduced to a small active channel
with major changes to the terrestrial and aquatic river environment. Flows further down the
river have been reduced to around 40-50 % of natural flows. In 2006 the State Government
decided to marginally increase the environmental flows to the Yarra River. This decision was
reversed in 2007 as a consequence of the very low inflows to the catchment in 2006. The
environmental flows agreed to in 2006 should be returned once the supply augmentations
are completed, and should be taken into account in determining long term supply and
demand.
We present scenarios of Melbourne‟s water storage levels based on supply (inflows) and
demand (population and per capita use) to give a broad-brush account of long-term water supply. While in reality, many factors will influence the actual outcome; this analysis looks
only at broad likely trends.
7/14/2019 Melbourne's Water Situation: The opportunity for diverse solutions
http://slidepdf.com/reader/full/melbournes-water-situation-the-opportunity-for-diverse-solutions 19/35
Page 13
4.1. Demand scenarios
We present six long-term demand scenarios which involve three levels of domestic direct
water demand and two estimates of Melbourne‟s population to 2051 based on migration and
the fertility rate. These are:
Scenario 1 This scenario considers 155 L/p/day demand from July-2009 through to June-2051. This
scenario represents an ongoing program of demand management, including increased water
use efficiency and supplementing central water supply with local sources, such as rainwater.
This corresponds to a reduction of approximately 37% of the average level of residential
consumption seen in the 1990‟s.
Scenario 1a - net annual overseas and internal migration gain to Melbourne 38,200 –
total fertility rate of 1.8
Scenario 1b - net annual overseas and internal migration gain to Melbourne 18,600 –
total fertility rate of 1.75
Scenario 2
Per capita water demand starts at 155 L/p/day from July-2009 to June-2013 and then
increases to 200 L/p/day by July-2025, reflecting the increase in availability of water with the
new water sources. This policy is similar to that outlined in the Central Region Sustainable
Water Strategy and is a level of consumption which would allow a modest version of
Melbourne‟s detached house and garden lifestyle to be maintained. This corresponds to a
reduction of approximately 20% of the average level of residential consumption seen in the
1990‟s.
Scenario 2a - net annual overseas and internal migration gain to Melbourne 38,200 -
total fertility rate of 1.8Scenario 2b - net annual overseas and internal migration gain to Melbourne 18,600 -
total fertility rate of 1.75
Scenario 3
Per capita water demand starts at 155 L/p/day from July-2009 to June-2013 and then
increases to 250 L/p/day by July-2025. This scenario represents a lapse of water use
efficiency and a return to unrestricted watering of gardens, taking into account the hard-wired
efficiency savings already built into the system.
Scenario 3a - net annual overseas and internal migration gain to Melbourne 38,200 -
total fertility rate of 1.8
Scenario 3b - net annual overseas and internal migration gain to Melbourne 18,600 –
total fertility rate of 1.75
Total water demand (in GL) is calculated by taking the residential population, multiplying by
per capita water demand (L/p/day), multiplying by 365 days, converting to GL and then
dividing by 0.6 to include industrial use and system losses.
7/14/2019 Melbourne's Water Situation: The opportunity for diverse solutions
http://slidepdf.com/reader/full/melbournes-water-situation-the-opportunity-for-diverse-solutions 20/35
Page 14
4.1.1. Popu lation estimates
There are two population estimates, reflecting high and medium growth. High growth
assumes Melbourne‟s population grows from 3.9 million persons in 2008 to 6.6 million
persons in 2051, similar to the recent ABS projections. This high growth assumes that the
recent high level of overseas migration will be sustained over the forecast period, and that
this will result in an annual net movement to Australia of 180,000 per year of whichMelbourne will receive 24%. This figure includes a small annual net loss from Melbourne to
elsewhere in Australia of 5,000 per year. It is also assumed that fertility in Melbourne will
remain at the relatively high fertility rate of 1.8.
Under the medium growth estimate Melbourne‟s population increases from 3.9 million in
2008 to 5.2 million by 2051. Net migration to Australia and Melbourne is set at approximately
half the level of high growth (net 90,000 persons with Melbourne again receiving 24%) and a
slight decline in the fertility rate to 1.75.
4.1.2. Total water us e to 2051
Table 2 and Figure 8 show the water usage under the outlined scenarios to 2051.
Table 2: Population and annual water usage (GL)* projections for Melbourne under various
scenarios to 2051
2016 2021 2026 2031 2036 2041 2046 2051
L o w
w a t e
r u s e
Scenario 1a
High population 4,426,436 4,765,742 5,091,725 5,403,836 5,705,560 6,000,845 6,288,142 6,561,653
Water use 417 449 480 510 538 566 593 619
Scenario 1b
Med population 4,187,023 4,394,170 4,580,128 4,745,520 4,893,639 5,027,213 5,145,397 5,244,924
Water use 395 414 432 447 461 474 485 495
M e d i u m
w a t e r u s e
Scenario 2a
High population 4,426,436 4,765,742 5,091,725 5,403,836 5,705,560 6,000,845 6,288,142 6,561,653
Water use 448 536 619 657 694 730 765 798
Scenario 2b
Med population 4,187,023 4,394,170 4,580,128 4,745,520 4,893,639 5,027,213 5,145,397 5,244,924
Water use 423 495 557 577 595 612 626 638
H i g h
w
a t e r u s e
Scenario 3a
High population 4,426,436 4,765,742 5,091,725 5,403,836 5,705,560 6,000,845 6,288,142 6,561,653
Water use 481 633 774 822 868 913 956 998
Scenario 3b
Med population 4,187,023 4,394,170 4,580,128 4,745,520 4,893,639 5,027,213 5,145,397 5,244,924Water use 455 584 697 722 744 765 783 798
Source: Population projections by CPUR; projection series commencing 2006 using ABS Estimated Residential
Population, Series B Sept. 2008. * Water projections do not include environmental flows.
7/14/2019 Melbourne's Water Situation: The opportunity for diverse solutions
http://slidepdf.com/reader/full/melbournes-water-situation-the-opportunity-for-diverse-solutions 21/35
Page 15
Figure 8: Water demand scenarios of 1) low per capita water demand, 2) medium per capita
water demand and 3) high per capita water demand; with population scenarios a) high
population and b) medium population.
1a
2a
3a
1b
2b
3b
0
200
400
600
800
1000
1200
1995 2000 2005 2010 2015 2020 2025 2030 2035 2040 2045 2050 2055
A n n u a l D e m a n d / G L
4.2. Water supply
We model two supply situations with a medium and low natural inflow to Melbourne‟s major
water storages in addition to projected levels of supply from augmentation projects (Figure
9). Environmental flows are not directly factored in, but are indirectly included in the system
losses component, which increases as a proportion of total use. The situations are as
follows:
Medium natural inflows
An average 200 GL of augmentation from Tarago, Pipeline and desalination from mid
2012. This assumes that the Sugarloaf Pipeline will not be operating at full capacity
for the period under consideration.
380 GL of annual average inflows, representing the average for the last ten years
Low natural inflows
An average 200 GL of augmentation from Tarago, Pipeline and desalination from mid
2012
300 GL of annual average inflows, representing the average for the last four years
7/14/2019 Melbourne's Water Situation: The opportunity for diverse solutions
http://slidepdf.com/reader/full/melbournes-water-situation-the-opportunity-for-diverse-solutions 22/35
Page 16
Figure 9: Water supply projections with medium and low inflows and augmentation after mid
2010
Augmented mediuminflows
Augmented low inflows
Low inflows
Medium in flows
0
100
200
300
400
500
600
700
800
900
1000
1 9 9 0
1 9 9 5
2 0 0 0
2 0 0 5
2 0 1 0
2 0 1 5
2 0 2 0
2 0 2 5
2 0 3 0
2 0 3 5
2 0 4 0
2 0 4 5
2 0 5 0
2 0 5 5
A n n u a l S u p p l y / G L
In summary, the augmented low inflows, totalling 500 GL/year, are less than what is required
for all but the lowest demand scenario (1b) shown in Table 2. This means that additional
sources of water would be required before 2050.
4.3. Supply-demand projections
This part of the report examines the implications of the demand and supply scenarios
developed above for water storage levels. Projections of supply levels for Melbourne‟s water
storages from July-2012 until June-2051 are shown below. For each set of projections, we
have identified positions where water supply will exceed demand until 2051 (white cells in
tables), where demand exceeds supply but without depleting storages to zero per cent (light
grey cells) and where water demand will exceed supply and storages would hypothetically bedepleted to zero per cent (dark grey cells).
The annual change in percentage system storage ( ΔS ) was calculated using the following
equation:
100
C
D I S S
i
Where;
S i - initial (previous year) supply level (GL)
I - annual inflows (GL) D - annual demand (GL)
C - system storage capacity
7/14/2019 Melbourne's Water Situation: The opportunity for diverse solutions
http://slidepdf.com/reader/full/melbournes-water-situation-the-opportunity-for-diverse-solutions 23/35
Page 17
4.3.1. Other con siderat ions and assump t ions
A number of other supply and demand elements have not been factored in to the calculations
presented in this report, or their values have been subject to certain assumptions, including
the following:
Demand elements:
Expansion of Melbourne water grid (e.g. connection to Geelong) not factored in
Restoration of environmental flows to levels agreed in 2006 not factored in
Additional environmental flows to the Thomson River not factored in
Yering pumping and weir harvests not factored in (estimated at 80-100 GL/year)
Supply elements:
North-South pipeline assumed to run at half capacity (35 GL/year)
Headworks environmental releases and spills not factored in (estimated at 80-100 GL/year)
We have assumed that the supply and demand elements listed approximately balance out
and do not significantly affect the overall result. The simplified modelling approach treats
Melbourne‟s water storages as one volume and does not consider non-linear responses,
such as emergency measures for extremely low storage levels. This analysis is intended as
a broad comparison between different levels of in f lows , populat ion and per-capita
demand .
7/14/2019 Melbourne's Water Situation: The opportunity for diverse solutions
http://slidepdf.com/reader/full/melbournes-water-situation-the-opportunity-for-diverse-solutions 24/35
Page 18
4.3.2. Supply -demand pro ject ion: medium average inf low s (380 GL)
Drop down lines have been inserted in Figure 10 and Figure 11 to indicate when Melbourne‟s
water storages reach 20 per cent of capacity. The purpose is to flag the time when the need
for action to act to limit demand or augment supply (or both) will become urgent. As is shown
in Figure 10 and Figure 11, this is usually several years before the storages would be fully
depleted.
Table 3: Percentage of storage capacity for supply-demand projections under medium average
inflows
Scenario
% of storage
capacity Year
1b (low per capita demand, medium population) 100% 2018 onwards
1a (low per capita demand, high population) 100% 2019 onwards
2b (medium per capita demand, medium population) 64% 2051
2a (medium per capita demand, high population) 0% 20433b (high per capita demand, medium population) 0% 2035
3a (high per capita demand, high population) 0% 2029
Figure 10: Projections of water supply levels under medium average inflows: 1) low per capita
water demand, 2) medium per capita water demand and 3) high per capita water demand; with
population scenarios a) high population and b) medium population.
1a
2a3a
1b
2b
3b
0
10
20
30
40
50
60
70
80
90
100
2005 2010 2015 2020 2025 2030 2035 2040 2045 2050 2055
S u p p l y L e v e l / %
7/14/2019 Melbourne's Water Situation: The opportunity for diverse solutions
http://slidepdf.com/reader/full/melbournes-water-situation-the-opportunity-for-diverse-solutions 25/35
Page 19
4.3.3. Supply -demand pro ject ion: low average inf lows (300 GL)
Table 4: Percentage of storage capacity for supply-demand projections under low average
inflows
Scenario% of storagecapacity Year
1b (low per capita demand, medium population) 100% 2025 onwards
1a (low per capita demand, high population) 1% 2051
2b (medium per capita demand, medium population) 0% 2038
2a (medium per capita demand, high population) 0% 2029
3b (high per capita demand, medium population) 0% 2026
3a (high per capita demand, high population) 0% 2023
Figure 11: Projections of water supply levels under low average inflows: 1) low per capita water
demand, 2) medium per capita water demand and 3) high per capita water demand; with
population scenarios a) high population and b) medium population
1a2a3a
1b
2b3b
0
10
20
30
40
50
60
70
80
90
100
2005 2010 2015 2020 2025 2030 2035 2040 2045 2050 2055
S u p p l y L e v e l / %
7/14/2019 Melbourne's Water Situation: The opportunity for diverse solutions
http://slidepdf.com/reader/full/melbournes-water-situation-the-opportunity-for-diverse-solutions 26/35
Page 20
4.3.4. Imp l icat ions of long-term supply -demand project ions
Should low average inflows eventuate, Melbourne‟s storages will be quickly depleted under
most of the scenarios considered. For example, under the high population and medium per
capita demand assumptions, there is a risk that the storages will be depleted by 2029. Under
this scenario (2a in Table 4), the drop down line indicates that storages will at 20 per cent of
capacity by 2024 (Figure 11). The low average inflow assumption of 300 GL (plusaugmentation from the Sugarloaf pipeline and the desalination plant) is plausible, as an
average inflow of 300 GL is more than occurred in 2006-07 and 2008-09.
The high population, high demand scenario (3a in Table 4) is of particular note should low
average inflows occur. The demand aspect of this scenario could occur if the Government
fails to actively maintain a conservation program. The government might be tempted to do so
after the additional water from the desalination plant becomes available. For this reason it is
important that some conservation measures are hard-wired into the system (e.g. low-flow
shower heads, washing machines and toilets). The population assumption is the same as
that projected by the Victorian Department of Planning and Community Development in its
Victoria in Future release of 2008. Under this scenario, the storages may peak (wheredemand exceeds supply) before 2020.
Should inflows return to medium levels before augmentation, that is 380 GL per year; the
situation is more comfortable. Under the low per capita demand scenarios the storages are
most likely to be full before 2020. These circumstances would raise questions about how the
Desalination Plant and the water network should operate once storages are full.
The supply-demand projections described above indicated that Melbourne needs to
immediately begin planning for either additional sources of water or some combination of
restraints to population growth and a strong demand management strategy.
5. The long term outlook
The long term scenarios to 2051 show that in the first few years after the desalinisation plant
comes on stream, Melbourne Water could remove all restrictions and/or return environmental
flows with little risk of water shortages, even under the high population assumption. However,
as early as 2020, if low inflows occur in a context of high population growth and high per
capita demand, the storages would peak and would require additional supplies to be brought
online before 2025. Under the medium flow scenario the peak in storage levels would be
more likely to occur after 2025, but new sources of water would be needed before 2030.
It is not proposed that any of these outcomes will actually occur. Should medium or low
inflows from the water catchments continue, future governments would have to act well
before the storages are empty. Rather, the scenarios indicate that under some plausible
assumptions, and even with the augmentation of water supplies from the Sugarloaf pipeline
and desalinisation plant, the Victorian Government will have to start planning now to deal
with inflows scenarios that are lower than the long-term average. This planning will have to
involve further augmentation of the water supply and/or a reduction in the projected demand
for water.
These new circumstances have arisen because of unforseen developments on the demandand supply side of the water equation. On the demand side, the recent surge in Melbourne‟s
population, if sustained, will add some 2.8 million extra consumers between 2006 and 2051
7/14/2019 Melbourne's Water Situation: The opportunity for diverse solutions
http://slidepdf.com/reader/full/melbournes-water-situation-the-opportunity-for-diverse-solutions 27/35
Page 21
rather than between 1 to 1.5 million as was assumed just a few years ago. On the supply
side, the climate change trends have raised the possibility of low flows continuing over the
long term.
The climate change trend has delivered several low inflow years, including just 165 GL in the
2006 calendar year and 287 GL in the 2008 calendar year. As indicated, the Victorian
Government has stated that it intends to remove water restrictions after the Desalination
Plant is operational. Also, the Government‟s most recent population projections are
consistent with the high population assumption included in our modelling.
In this final section of the report we examine some of the options available to achieve a
reduction in per capita demand for water. We do not consider supply-side options in detail.
This is not to say that they will not be part of the Government‟s response to the water supply
crisis the scenarios depicted above indicate could occur. There are serious environmental
costs associated with some supply side solutions, as would be the case should a further
desalinisation be built or a dam constructed on another stream, the most likely being the
Mitchell river. The financial costs of such responses are also steep, as Victorian consumers
will discover when the high price of water from the desalinisation plant is factored into their water bill.
5.1. Supply-oriented options
As noted, this report will not consider alternative water supply options in any detail, except to
point out the cost of supply options relative to demand-oriented options, which is
demonstrated in Figure 12. This figure shows that demand management is one of the most
consistently low-cost solutions to meeting water needs on a per-kilolitre basis. In contrast,
other supply-side options such as rainwater tanks, long-distance pipelines and water recycling can, in some instances, generate much higher costs per kilolitre. For example, the
least expensive rainwater tank example would have cost $2.15 per kL, whereas the most
expensive example of rainwater tanks provided water at $12.30 per kL. This highlights that a
range of supply-side options are required to deal with local variation, such as in the more
elevated regions of Melbourne where water pumping costs might increase the cost of
centralised supply and make decentralised options more cost-effective.
In planning for water provision for Melbourne after the next decade, any options considered
should take into account whole-of-lifecycle costs (including energy use and externalities on a
geographic basis) and should contain a mix of both centralised/decentralised and rainfall
dependent/independent options. Future water planning should take place along with and inthe context of urban design, population growth and the uptake of alternative energy sources.
Most importantly, there should be public discussion about the effective choices that will be
made.
7/14/2019 Melbourne's Water Situation: The opportunity for diverse solutions
http://slidepdf.com/reader/full/melbournes-water-situation-the-opportunity-for-diverse-solutions 28/35
Page 22
Figure 12 Direct costs of water supply/demand options – Sydney, Adelaide, Perth, Newcastle
(Sources: Marsden Jacob Associates 2006; PMSEIC Working Group 2007).
5.2. Demand-oriented options
The next section outlines options for reducing water demand. It is unlikely that one option
only will be sufficient, rather a range of these options should be packaged together.
5.2.1. Cri ter ia for managin g the demand for water
Demand management policy needs to be based on a number of principles, as follows:
Water saving attribute: The policy needs to be an effective means of saving water.
Cost share burden: The burden of a reduced availability of water should be shared
between community sectors: domestic, commercial and landscape in proportion to
their current usage.
Ease of supply of product, roll-out and installation: Policies need to be a mix of short
term immediate responses to longer term approaches. It may be that some policies
can have a sunset clause as other policies unfold over time.
Equity considerations: Equity should be built into all policies to assist those who havethe greatest difficulties paying for water.
7/14/2019 Melbourne's Water Situation: The opportunity for diverse solutions
http://slidepdf.com/reader/full/melbournes-water-situation-the-opportunity-for-diverse-solutions 29/35
Page 23
5.2.2. Reduct ion in rate of pop ulat ion growth
Our scenarios show that for the three levels of per capita demand investigated, including a
return to unrestricted demand, the storages would be under much less threat under the
medium population scenario than under the high population scenario Under the medium
population assumption Melbourne‟s population reaches 5.2 million by 2051 rather than 6.6
million under the high scenario.
Table 4 shows that under the high population scenario, if the medium average inflow
scenario eventuates, the storages would be peak before 2020 if the high per capita water
consumption pattern is maintained. Even under the low per capita consumption assumption,
if the high population scenario comes to pass under the low average inflow outcome, the
storages would be depleted before 2051.
By comparison, under each of the per capita demand assumptions, if accompanied by
medium population growth there is a substantial reduction in the overall consumption of
water and much less pressure on the storages.
One particular scenario is worth highlighting. This is where the medium population outlook iscombined with low per capita water demand. Though as noted below this low demand
scenario will require some sacrifices on the part of Melbourne water consumers, there are
potential reform measures which will ameliorate these sacrifices. Table 4 shows that even
under the low average inflow assumption, should low per capita demand occur along with
medium population growth, the storages would be full by 2025. By contrast, if this low
average inflow occurs, and is accompanied by low per capita consumption but high
population growth, the storages would be depleted by 2051.
The policy changes needed to achieve the medium population outcome are not
unprecedented. A level of net annual migration of 90,000 is not unusual in Australia. Net
overseas migration reached a peak during the 1980s of 157,400 in 1988-89. In the aftermathof the early 1990s recession, the Commonwealth Labor Government cut the migration
program back severely. It was not until the year 1999-2000, when net overseas migration
reached 107,000, that it once again exceeded 100,000. By 2007-08 the ABS estimates that
net overseas migration was 213,700. A cut in the migration program, assuming that it was
reflected in lower settlement levels in Melbourne, would be a relatively costless part of the
solution to the water predicament.
The problem from the Victorian perspective is that successive state governments have
strongly supported increased migration levels set by the Commonwealth Government in
Canberra. At present there is no mechanism whereby the Commonwealth Government can
be made accountable for the downstream costs of providing for the extra population (as with
augmentation of the water supply).
5.2.3. Tightening w ater use restr ict ions
Water restrictions are an effective means of reducing consumption. Water restrictions were
put in place in November 2002 and permanent water saving measures in March 2005. In
April 2007, compulsory Stage 3a water restrictions were instigated and are still current. They
are said to be designed to „save water while minimising the impact on businesses and
community sporting facilities‟ (Victorian Government 2009). The restrictions can be
summarised as follows:
Domestic: No watering of lawns, a two-hour window to water gardens twice a week,
no car washing, restrictions on topping up pools or spas.
7/14/2019 Melbourne's Water Situation: The opportunity for diverse solutions
http://slidepdf.com/reader/full/melbournes-water-situation-the-opportunity-for-diverse-solutions 30/35
Page 24
Landscape: One in four sports grounds can be watered except for exempt playing
surfaces, public gardens can be watered by drippers on a two hour basis two times a
week or in accordance with a WaterPlan.
Commercial: There are no water restrictions where water is used in the production
process. Commercial car washers which use 70 litres or less of water per car are
allowed to operate. Other exceptions (with some conditions) exist for commercialnurseries, poultry sheds, other animal husbandry businesses and construction sites.
The problem with the maintenance of such a restrictive regime is that it would be likely to
lead to a loss of Melbourne‟s landscape. Severe water restrictions, if continued, will put
Melbourne‟s reputation as a liveable, garden city in jeopardy. They will also impact on th e
capacity for home food production and community gardens, two important means of
addressing the rise in food prices associated with climate change itself and mitigation policy
such as a carbon price.
In the case of commercial users, they are progressively required to submit and comply with
water saving plans. Businesses using 10 megalitres of water or more per year must complete
a water management action plan (waterMAP program) (Melbourne Water 2009a). There are1,850 business customers in Victoria that fit into this group. In 2003, a pilot program
“Pathways to Sustainability” involving the highest 200 non-residential water consumers in
Melbourne resulted in 6.2 billion litres of water being saved in Melbourne since 2001,
representing a 13% efficiency gain.
5.2.4. Pri ce inc reases
As noted, the price of water will increase sharply as a result of the costs of recent
augmentation measures. Many studies have documented the fact that water use alters in
response to price (Baumann, Boland & Hanemann, 1997) and that pricing policy is costeffective in reducing water usage (Olmstead & Stavins 2008). Pricing which reflects the
scarcity of water will encourage the utilization of other sources of water, such as recycled
water. Full cost recovery of water was recommended in the recent ADC Infrastructure 21
Summit (Young & Westacott 2008). A rise in the cost would generate a better appreciation of
the value of water. Pricing would reflect the actual cost of water supply as well as a scarcity
factor. This would mean that the cost of externalities such as ecological losses from reduced
stream flow should be factored in the price, as well as downstream externalities in the
sewage charge. An alternative approach would be to price water variably according to
storage levels, the price rising as storage levels dropped (Olmstead & Stavins 2008).
Such a price rise should be for all sectors and all users. However, this policy should includeprovision for hardship factors as water pricing is regressive, with lower income households
being disproportionately disadvantaged. Households with a Health Care Concession Card
should be exempt from price rises or be provided with rebates. Other households with a low
income should be assisted with free provision and installation of water tanks or grey water
systems. Grants could be offered along with interest free loans – repayable from cost
savings due to alternative water sources. The policy could also provide transition planning for
some heavy water using industries, such as coal-fired power stations.
5.2.5. A pp eals for conservation
Target 155 , which began in December 2008, promotes voluntary residential water
conservation to bring water consumption in Melbourne down to 155 litres per person per day,
representing levels of average per capita demand expected under domestic Stage 4
7/14/2019 Melbourne's Water Situation: The opportunity for diverse solutions
http://slidepdf.com/reader/full/melbournes-water-situation-the-opportunity-for-diverse-solutions 31/35
Page 25
restrictions. The target of 155 litres was exceeded for most of the very dry start to 2009. Over
the three months of summer the average use was 177 litres per person per day. However,
low use during winter and spring resulted in the target being met after 50 weeks, with an
average of 152 litres per person per day, compared to 165 L/p/day over the same period one
year earlier. Future conservation campaigns could target even lower residential water use.
There is little doubt that appeals for conservation are likely to be effective when there is a
short term crisis in water supply such as has been experienced in South-East Queensland in
recent years. But the impact may be weakened if extended over decades – as would be
necessary in the case of the period to 2051 examined in this report. This is especially the
case if householders are aware that any savings they make simply accommodate the needs
of additional residents.
A possible solution is to set household targets for water use and give consumers the choice
on how to use water within these targets. Of course, this would be difficult to enforce;
however, so is the voluntary Target 155 program.
5.2.6. En forc ed eff icienc ies
Significant savings can be made through the installation of water efficient appliances, grey
water systems or household tank storages. The use of a dual flush toilet system for domestic
and business use is an example, For a family of four, the installation of a dual flush toilet can
save more than 35,000 litres of water a year (Melbourne Water 2009b). Approximately 20%
of toilets in Melbourne are single flush (caroma dorf 2009). Changing these to dual flush
toilets could save 15.47 GL of water annually. Further water savings of 10% could be
achieved if the toilet suite integrates a hand-washing basin where the water is then used to
flush the toilet.
Various approaches have been shown to reduce water use in urinals. Measures such as new
flush valves and diaphragm replacement lead to a reduction of water use per flush of
between 0.76 litres per flush to 3.9 litres per flush. A US „standard‟ flush is 14.1 litres (Van
Gelder 2008). In the case of washing machines, front-loading machines are usually the most
water efficient, using up to 50% less water than a top-loading machine. Sydney has had a
policy since March 2006 to provide a rebate of $150 for a 4 star or 5a water efficiency rating
(Sydney Water 2007).
In the case of industry price increases, this may not have much impact in reducing water
consumption because some industries have the capacity to pass on costs and higher prices
down the supply chain and to consumers. Thus, it is also important to introduce mandatory
water efficiency standards to industry for water uses associated with production. The four Latrobe Valley electricity generators use approximately 130 GLs per annum of drinkable
water from the Latrobe river system, stored in the Blue Rock dam, not a water supply
presently used for Melbourne. Planning should commence as soon as possible to move
these generators to an alternative water source, such as recycled or desalinated water.
There is a need to fast track the waterMAP program. At present, only 11% of the heaviest
commercial users of water have completed a water management action plan. If the same
saving rate is achieved with the remaining 1,650 large business customers, this should
provide an additional saving of about 6.2 GL per annum. This program should also be
extended to progressively include the group of businesses with the next highest water use.
Penalties can apply to business and other non-residential sites that do not comply with theserequirements in accordance with the set timeframes. As with households, on the grounds of
equity there may need to be a small number of exclusions or concessions to industry.
7/14/2019 Melbourne's Water Situation: The opportunity for diverse solutions
http://slidepdf.com/reader/full/melbournes-water-situation-the-opportunity-for-diverse-solutions 32/35
Page 26
5.2.7. Knowledg e dissem inat ion and socia l market ing
Goodwill around water saving could be further developed in the community and with industry
through the dissemination of information about water scarcity and ways to reduce water
usage. In particular, community consultation on recycling water to potable standard should
be ramped up. A water treatment facility should be constructed at the Eastern Treatment
Plant to supply industry and golf courses, with the ability to be upgraded in order to treatwater to drinking quality. The production of drinking quality water can be demonstrated on a
pilot scale and used to engage with the public about the potential to upgrade the plant for full
indirect potable reuse. Water conservation campaigns need to be maintained and should
highlight the long-term benefits of reducing water demand. Melbourne Water and water
retailers should continue to advertise water saving hints on their websites and water bills.
5.2.8. WaterSmart
The WaterSmart program is based on a model used to assist people with travel. The
TravelSmart program in SA has been shown to produce an 18% reduction in kilometres
travelled by participants, while non-participants increased their kilometres travelled by 6%.
The WaterSmart program involves a random sample of 80,000 households. The program
commenced in June last year and while the evaluation has yet been completed, early
evidence suggests a similar scale of success to the TravelSmart program. The approximate
cost is $100-$170 per participating household. This cost includes using the voluntary
behaviour change approach and:
Selecting the sample of households for intervention and control groups
Phoning/visiting the households and holding a conversation of about 10-15 minutes
(possibly with a survey on the appliances in the household)
Preparing (in collaboration with the client) „tools‟ that would help people make
changes (often in the form of personalised information)
Analysis of meter readings for both intervention and control groups
Follow up calls over 6-9 months to see if people have further questions and need
more assistance.
5.2.9. Smart meterin g
Smart metering systems and control technologies can result in greater water conservation
(Young & Westacott 2008). It provides users with real time information about their water usage. Such a system would provide self-corrective action about specific behaviours which
have heavy water usage. Smart metering could be of benefit in domestic, industrial,
landscape and irrigation sectors. Victoria is already rolling out smart electricity meters, so
there is an opportunity for a concurrent roll-out of water meters or meters which integrate
information on electricity, gas and water usage.
Smart metering for landscape watering also has the potential to monitor specific site
conditions such as plant and soil type, soil moisture and weather conditions and
automatically adjust the water given to each plant (Harrelson 2008). Programs to encourage
the use of this have been undertaken in the US, often accompanied by a significant rebate
for the customers. However, the schemes were found to need better support services, withimproved installation and customer follow-up.
7/14/2019 Melbourne's Water Situation: The opportunity for diverse solutions
http://slidepdf.com/reader/full/melbournes-water-situation-the-opportunity-for-diverse-solutions 33/35
Page 27
5.2.10. Ass istance to low incom e hou sehold s
Sydney Water provides services for the domestic market under the banner of Waterfix. The
program commenced in 2000 and installs three-star rating showerheads, tap flow regulators,
toilet system flush arresters, repair of minor water leaks. The service is offered for $22 with
concession hard holders getting a free service. A similar service is offered to Department of
Housing customers. There is also a „Do it Yourself Water Saving Kit‟ which providesinformation on how the householder can undertake this themselves.
As at 30 June 2007, there were 42,732 homes serviced for the year, resulting in a water
savings of 20,897 litres a year per household. The cost is $94 per household, plus marketing
of $55 per household. The cost effectiveness would depend on the life of products and
repairs undertaken.
Victoria has a similar scheme, the Energy and Water Taskforce, which has undertaken
Energy and Water audits and free retrofits to the value of $300 per household for 5,000 low
income households. The program which works on a social enterprise model with welfare
non-government organizations and incorporates job training for unemployed people, results
in two-thirds of households involved in the program stating that they are now always
conscious of saving water.
6. Conclusions
The purpose of this report has been to draw attention to the water supply challenges
presented by the long drought in Melbourne‟s water catchments. If , as seems possible, the
water flowing into Melbourne‟s dams stabilises at levels well below those assumed in the
past fifty years, then major policy changes affecting both supply and demand for water will benecessary.
The modelled scenarios indicate that Melbourne faces medium term and long term
challenges. For the long term, the current augmentation of the supply via the Sugarloaf
pipeline and the desalination plant is likely to provide some insurance for a decade or so.
However, this will not prevent water restrictions from recurring and should not be considered
to be “drought-proofing” Melbourne. However, given the risk that low average inflows will be
sustained and that population growth will continue to be high, planning for additional supply
should be undertaken.
This report is not intended to provide any definitive answers as to which policy options should
be given priority. Rather our purpose is first to increase awareness of the possibilities of
severe shortages of water, and to provide a basis for public discussion about prospective
options for dealing with the crisis.
It is suggested that this overview be followed by a more detailed analysis of the
cost/effectiveness of the range of demand management options. Such an analysis would
include calculations of water saved, how the options met the outlined principles (Page 22)
and policy implications and the introduction and on-going management barriers and
facilitators. Key points and recommendations from this report are given on pages 2 and 3.
7/14/2019 Melbourne's Water Situation: The opportunity for diverse solutions
http://slidepdf.com/reader/full/melbournes-water-situation-the-opportunity-for-diverse-solutions 34/35
Page 28
7. References
Australian Bureau of Statistics, (2008) Population Projections, Australia, 2006 to 2101, Cat. 3222.0
Baumann, D.D., Boland, J.J and Hanemann, W.M., (1997) Urban Water Demand Management andPlanning, McGraw-Hill, New York.
BOM, (2009a) http://www.bom.gov.au/climate/enso/ Accessed 16 November 2009
BOM, (2009b) http://www.bom.gov.au/climate/IOD/positive/ Accessed 16 November 2009
BOM, (2009c) http://www.bom.gov.au/climate/coupled-model/poama.shtml Accessed 16 November 2009
Cai, W. & Cowan, T. (2008a) Dynamics of late autumn rainfall reduction over south eastern Australia.Geophysical Research Letters, 35, L09708.
Cai, W. & Cowan, T. (2008b) Evidence of impacts from rising temperature on inflows to the Murray-Darling Basin. Geophysical Research Letters, 35, L07701.
Caroma Dorf, (2009) eco logical solutions, Caroma Industries Limited, South Melbourne.
CSIRO, (2005) Melbourne Water Climate Change Study: Implications of Potential Climate Change for Melbourne‟s Water Resources. CSIRO Urban Water and CSIRO Atmospheric Research,Melbourne.CSIRO (2007) Climate change in Australia. Commonwealth Scientific andIndustrial Research Organisation, Australia.
DSE, (2004) Our Water Our Future: Securing Our Water Future Together. Victorian GovernmentWhite Paper.
DSE, (2007a) Our Water Our Future: The Next Stage of the Government's Water Plan. DSE, VictorianGovernment, Melbourne.
DSE, (2007b) Melbourne Augmentation Program. Sugarloaf Interconnector. Victorian GovernmentDepartment of Sustainability and Environment, Capital Projects Division, Melbourne.
DSE, (2008) Augmentation of the Melbourne Water Supply System. Analysis of Potential SystemBehaviour. Melbourne, State of Victoria. Department of Sustainability and Environment.
ENRC, (2009) Inquiry into Melbourne‟s Future Water Supply, Environment and Natural ResourcesCommittee, Victorian Government.
Gauchi, S., (2009) El Nino fear as dams fall to new low, http://www.theage.com.au/national/el-nino-fear-as-dams-fall-to-new-low-20090516-b6t4.html?page=-1 Accessed 1 June 2009.
Harrelson, D., (2008) Creating Demand: Four approaches for promoting „Smart‟ irrigation controllers tohomeowners, WaterSmart Innovations Conference, South Point Hotel and Casino, Las VegasOctober 8 to 10.http://www.awwa.org/files/Resources/Waterwiser/references/PDFs/sustainable2008_mon3-5.pdf
Accessed 3 March 2009.
Ker, P., (2009a) Slowing the flow as poll pledge turns dry, The Age,www.theage.com.au/environment/slowing-the-flow-as-poll-pledge-turns-dry-20090405-9t9x.html
Ker, P., (2009b) Melbournians ignore 155-litre water target, The Age,www.theage.com.au/national/melbournians-ignore-155litre-water-target-20090302-81p3.html
Accessed 2nd March 2009
Marsden Jacob Associates (2006). Securing Australia's Urban Water Supplies: Opportunities and
Impediments, A discussion paper prepared for the Department of the Prime Minister and Cabinet.Melbourne Water (2003) Water Resources and the Environment 2002/03. East Melbourne.
Melbourne Water (2009a) WaterMAP http://ourwater.com.au/saving/industry/watermap
Melbourne Water (2009b) Saving water indoors http://ourwater.com.au/target155/saving-indoors
Olmstead, S.M. and Stavins, R.N., (2008) Comparing Price and Non-price Approaches to Urban Water Conservation; Fondazione Eni Enrico Mattei, Working Paper 2008:66.
PMSEIC Working Group (2007). Water for Our Cities: building resilience in a climate of uncertainty,Prepared by an independent working group of the Prime Minister's Science, Engineering andInnovation Council.
Sinclair Knight Merz, (2005) Determination of the Minimum Environmental Water Requirements for theYarra River , September, 7
Sydney Water, (2007) Water Conservation and Recycling Implementation Report 2006-2007
Van Gelder, R., (2008) High Efficiency field research: Interim Observations, WaterSmart InnovationsConference, South Point Hotel and Casino, Las Vegas October 8 to 10.
7/14/2019 Melbourne's Water Situation: The opportunity for diverse solutions
http://slidepdf.com/reader/full/melbournes-water-situation-the-opportunity-for-diverse-solutions 35/35
http://www.awwa.org/files/Resources/Waterwiser/references/PDFs/sustainable2008_mon3-5.pdf Accessed 3 March 2009.
Victorian Government, (2006a) Central Region Sustainable Water Strategy: Action to 2055.
Victorian Government, (2006b) Water Supply-Demand Strategy for Melbourne 2006-2055.
Victorian Government, (2009) Melbourne Water, Water Restrictions.http://www.melbournewater.com.au/content/water/water_storages/water_storages.asp#2
Accessed 8 March 2009.
Water Resources Strategy Committee, (2002) 21st Century Melbourne: a WaterSmart City: FinalReport.
Young, M. and Westacott, J., (2008) Water, A new paradigm, in Stanley, J. (ed) Proceedings from ADC Infrastructure 21: From Incrementalism to Transformational Change, 6 th and 7th October,Brisbane, Australia.
Appendix A
Domestic water restriction trigger levels for Melbourne Trigger Level (percentage of water in storage )*
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Stage 1 52.2 50.7 47.8 46.3 45.9 44.8 45.9 48.0 50.7 52.2 53.9 53.0
Stage 2 44.6 43.6 41.6 40.6 40.3 39.7 40.3 41.7 43.6 44.6 45.7 45.1
Stage 3a 36.9 36.4 35.5 35.0 34.9 34.5 34.9 35.5 36.4 36.9 37.5 37.2
Stage 4 29.3 29.3 29.3 29.3 29.3 29.3 29.3 29.3 29.3 29.3 29.3 29.3
*Rounded to one decimal point
Source: Melbourne Water, www.melbournewater.com.au accessed 1 June 2009