A fresh look at dual reticulation

June 2014

A fresh look at dual reticulationAn assessment of the performance and ongoing viability of dual reticulation schemes on the Gold Coast, the assessment utilises the Australian Water Recycling Centre of Excellence’s Total Economic Value Framework.

Irrigation Australia National Conference

Presented by: Kathy Baker

Executive Coordinator Integrated Water Cycle Planning

Gold Coast Water

June 2014

Slide 3

Background

Prior to 2006, GCW owned and operated its bulk water supply assets

Pimpama Coomera Waterfuture Master Plan (including Class A+ recycled water) adopted in 2004

By 2056, Class A+ predicted to contribute 20ML out of 366ML

Millennium drought effecting South East Qld

10 years since adoption – appropriate to review and consider the current and future costs and benefits

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Map…

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Class A+ Uses:Outdoor – garden irrigation, car washing

Indoor - toilet flushing

Fire fighting

Slide 7

Current situation

Class A+ to 6000 properties in the Pimpama Coomera region

Use 0.5% (0.8 ML/day) City’s total water demand

10 ML/day is supplied by Class B/C recycled water schemes

Class A+ usage rate much less then expected

Only 8 ML/day expected in 50 years (2.4%)

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Slide 8

Key changes since adoptionIssues Assumptions/Outcomes

DroughtMillennium drought broke and water use behaviours have changed significantly in SEQ

Bulk water State Government took ownership

Population projections Growth rates have slowed from those projected for the PIP.

Environmental discharge No Pimpama River release.

Outdoor water useGeneral outdoor water use has decreased by 65% compared with original assumptions.

Household recycled water demand

Actual recycled water demand per household is currently 75% less than that assumed for original demand projections.

Scheme capital costsWOL (50yrs) capital costs for Class A+ recycled water, approx. double original estimate in the PCWF Master Plan.

Scheme operating costsWOL O & M costs of Class A+ treatment & distribution system approx. 10 times greater than originally estimated.

Slide 9

Issues

Cross-connections – complicated pipework on-lot and off-lot

Household audits

Slide 10

Value and viability assessments

Not financially viable - cancelled future expansion of DR into the Stapylton, Yatala and Cabbage Tree Point areas

Detailed Value Assessment of Pimpama Coomera

Total economic value of recycling

– financial, environmental and social factors

Australian Water Recycling Centre of Excellence

Slide 11

End of dual reticulation for City of Gold Coast

Council resolved in December 2013 to discontinue implementation of dual reticulation on the Gold Coast due to:

High cost of operating and maintaining the scheme High cost of constructing new capital infrastructure Low demand usage Negative net “value” (costs outweigh benefits) Significant regulatory monitoring and reporting requirements Risk of cross connections

Estimated to save rate payers $3 million/year or $114 million over 40 years (in 2013 dollars)

Slide 12

Transition Plan to decommission Class A+ supply

Potable water to be supplied via both potable and recycled water networks

Initially operated as discreet systems (no mixing)

Class C return main from Pimpama STP to Coombabah STP

‘Switch over’ estimated to occur by December 2016

Slide 13

Existing Recycled Water SchemeExisting Recycled Water Scheme

- Northern Supply Scheme

- Southern Supply Scheme

Class B/C

- Approximately 50 fixed customers

- Some 400 Recycled Water Carrier Customers

- Total reuse for the past 5 years ranges from 16.5% - 20.3%

- Total irrigated area approximately 1700ha

- Irrigation of Sporting Fields, Council owned Parks, Schools, Nurseries, STP wash-down, Municipal Irrigation and Industrial / Commercial Use

Recycled Water Reuse vs Rainfall

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Recycled Water Reuse Target

Slide 14

Where to from here? Release

-Seaway-Ocean?

Local Opportunities

- Identified further open space irrigation

Additional treatment Class C to Class A+

- Jupiter’s Casino

- Potential Commonwealth Games venues

Slide 15

Where to from here? Potential Northern Recycled Water Scheme

PO Box 5042 Gold Coast MC QLD 9729P 1300 GOLDCOASTE mail@goldcoast.qld.gov.auW cityofgoldcoast.com.au