MELBOURNES WATER INFRASTRUCTURE STRATEGIES: GAPS IN INTEGRATED - - PowerPoint PPT Presentation

MELBOURNE’S WATER INFRASTRUCTURE STRATEGIES: GAPS IN INTEGRATED URBAN WATER MANAGEMENT

Presenter: Casey Furlong (RMIT / WaterRA) Co-authors: Ryan Brotchie (GHD) Robert Considine (Melbourne Water) Greg Finlayson (GHD) Lachlan Guthrie (RMIT)

Content of presentation

1. Melbourne’s challenges 2. Infrastructure responses 3. Planning for uncertainty 4. Integrated Urban Water Management 5. IUWM strategy case studies 6. Proposed IUWM infrastructure solutions 7. Gaps in IUWM processes 8. Discussion and conclusion

RMIT University - Casey Furlong

Melbourne's challenges

• 4 million people now, 8 million

people by 2050, increasing demand on services

• Urban footprint will increase by

43% by 2050

• Impacts of urbanisation on

waterways & bays (from stormwater runoff & wastewater discharges)

• 1997 - 2009 drought:13%

decrease in rainfall led to 39% decrease in reservoir inflows

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100 200 300 400 500 600 700 800 900 1000 1900 1903 1906 1909 1912 1915 1918 1921 1924 1927 1930 1933 1936 1939 1942 1945 1948 1951 1954 1957 1960 1963 1966 1969 1972 1975 1978 1981 1984 1987 1990 1993 1996 1999 2002 2005 2008 2011 2014 Average rainfall (mm) Year Average rainfall 1900‐2014: 648 mm/yr Federation Drought 1895‐1902* WWII drought (10 years) 1936‐1945: 574 mm/yr (‐11%)

*Federation drought is formally between 1885-1902, however rainfall data is not avalaible prior to 1900

Millennium Drought (12 years) 1997‐2009: 561 mm/yr (‐13% from average)

Infrastructure and policy responses during and post drought

• Major desalination plant (one

third of city’s current demand)

• Inter-basin transfer pipeline
• Combined capital cost > $5B
• 20% water recycling target set

and achieved (mostly agricultural)

• Water efficiency campaign:

Target 155 (L/person/day)

• Incentives for rainwater tanks

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Planning for uncertainty: population and climate

• Climate change predicted to

result in reduced rainfall & inflows, with more intense rainfall events & sea level rise

• Population forecasts revised
• ften, high variation
• Climate change and uncertainty

government priority 2004 – 2011

• Scenario planning conducted to

plan for uncertain future

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Integrated Urban Water (Cycle) Management

• 2009 onwards IUWM has

become popular

• Strategic, long-term, integrated

planning approach which considers all water services, sources, stakeholders, and impacts in order to create the best possible community

• utcomes
• Associated with recycled water

and stormwater harvesting

• Planning done through IUWM

Strategies/Plans

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IUWM Strategies/Plans

• This research has considered 9

strategies

• Various scales of investigation:

residential housing developments up to one third of Melbourne

• Investigate variety of options

including stormwater to potable/non-potable, wastewater to non-potable & rainwater tanks

• Do not consider wastewater to

potable

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Option implementation

Recommendation of options Implementation plan with next steps

Option selection

Technical evaluations Cost benefit analysis Multi criteria assessment

Identification of possible options

BAU option development IUWM options development Removal of unfeasible options

Problem definition

Assembling of stakeholders Setting of

• bjectives

Risk management

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Proposed IUWM infrastructure solutions

1. Collection of stormwater in wetlands and then treatment and injection to potable network 2. Non-potable reuse from wastewater treatment plants, sewer mining and stormwater harvesting

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Financial assessment of IUWM options

• Options compared using Long Run Marginal Costs, shown that

IUWM solutions will cost more than business as usual

• In some cases up to $700M more, but in others only slightly
• Justified through environmental, liveability and resilience benefits

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Gaps in the IUWM strategy processes

Climate change impacts

Increased water demand Lower rainwater and stormwater yields (and runoff) Lower water supply yields Flooding Enviro flow demands

Urban Irrigation Seasonal

• r annual

changes Changes to rainfall intensity Seasonal Inflow variability Rainfall events Sea Level Rise

1 Botanic Ridge Growth Area



2 East Pakenham 3 Casey Clyde Growth Area 4 WFN: Growth Areas

 

5 Water Future Central

 

6 Fishermans Bend

 

7 Melton Growth Area 8 Sunbury Growth Area



9 Western Region Water Balance

     

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• Consideration of climate change projections
• Scenario planning (single possible future scenario used)
• Demonstration or valuation of resilience/liveability
• Justification for environmental targets (no clear policies exist)

Discussion

• IUWM is extremely difficult and complex primarily because it involves

attempting to justify additional costs through non-monetary benefits

• Significant cost increases are partially justified through environmental benefits

to waterways, but there is no clear policy guidance to provide justification

• The IUWM solutions proposed are more climate independent than dam water

supplies, but less than desalination and direct potable reuse which were not considered

• Strategies do not use scenario planning and so fail to assess resilience
• Strategies generally failed to incorporate climate change projections, and it is

not clear how significant an impact this would have on recommendations

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Conclusion

• IUWM processes can help with climate change adaptation,

particularly if all options are considered including desalination and potable reuse

• What you need to effectively conduct IUWM strategies are:

1. Clear environmental targets 2. Scenario planning 3. A financial assessment methodology which allows investigations at different scales (e.g. Long Run Marginal Costs)

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Acknowledgements

• Co-authors
• RMIT University, Water Research Australia, GHD and Melbourne

Water Corporation

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