Transcript A fresh look at dual reticulation
A fresh look at dual reticulation
June 2014
A fresh look at dual reticulation
An 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
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 Slide 3
Map… Slide 4
Map… Slide 5
Map…
Class A+ Uses:
Outdoor – garden irrigation, car washing Indoor - toilet flushing Fire fighting Slide 6
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%) 350 300 250 200 150 100 50 0
8
Total Class A+ Recycled Water Demand Total City Potable Water Demand
0.8
152 Now 325 In 50 years
Slide 7
Key changes since adoption
Issues Assumptions/Outcomes
Drought Bulk water Population projections Environmental discharge Outdoor water use Household recycled water demand Millennium drought broke and water use behaviours have changed significantly in SEQ State Government took ownership Growth rates have slowed from those projected for the PIP. No Pimpama River release.
General outdoor water use has decreased by 65% compared with original assumptions.
Actual recycled water demand per household is currently 75% less than that assumed for original demand projections.
Scheme capital costs WOL (50yrs) capital costs for Class A+ recycled water, approx. double original estimate in the PCWF Master Plan. Scheme operating costs WOL O & M costs of Class A+ treatment & distribution system approx. 10 times greater than originally estimated.
Slide 8
Issues
Cross-connections – complicated pipework on-lot and off-lot Household audits Slide 9
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 10
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 11
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 12
Existing Recycled Water Scheme
60 50 40
Existing Recycled Water Scheme Recycled Water Reuse vs Rainfall
- Northern Supply Scheme 2500 - Southern Supply Scheme
Class B/C
2000 - Approximately 50 fixed customers 1500 Recycled Water Leaving WWTP 30 20 10 Rainfall (mm) Recycled Water Reuse Target - Total irrigated area approximately 1700ha 500 - Irrigation of Sporting Fields, Council owned Parks, Schools, 0 2000 2001 2001 2002 2002 2003 2003 2004 2004 2005 2007 2008
Financial Year
2009 2009 2010 2010 2011 2011 2012 Slide 13
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 14
Where to from here? Potential Northern Recycled Water Scheme
Slide 15
PO Box 5042 Gold Coast MC QLD 9729
P
1300 GOLDCOAST
E
W
cityofgoldcoast.com.au