Water Security for Wangaratta
DEPARTMENT OF ENVIRONMENT AND PRIMARY INDUSTRIES
Options Evaluation and Indicative Costing
Phase 2 Project Report | Final
Contract No. 306796
August 2014
Options Evaluation and Indicative Costing
Water Security for Wangaratta
Project no: VW07492
Document title: Options Evaluation and Indicative Costing
Document no: Phase 2 Project Report
Revision: Final
Date: August 2014
Client name: Department of Environment and Primary Industries
Client no: Contract No. 306796
Project manager: Simon Lang
Author: Simon Lang, Tara Smith, Elisabeth Norman, Peter Corrie, Michelle Freund
File name: DMCA/VW07492
Sinclair Knight Merz Pty Ltd (Jacobs)
ABN 37 001 024 095
Level 11 452 Flinders Street
Melbourne VIC 3000 Australia
PO Box 312
T +61 3 8668 3000
F +61 3 8668 3100
www.jacobs.com
COPYRIGHT: The concepts and information contained in this document are the
property of Sinclair Knight Merz Pty Ltd (Jacobs). Use or copying of this document in
whole or in part without the written permission of Jacobs constitutes an infringement
of copyright.
Final
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Options Evaluation and Indicative Costing
Document history and status
Revision Date
Description
By
Review
Approved
Draft A
13.06.14 Draft for comment by the Project
Steering Committee
S. Lang K.
Austin
K. Austin
Final
Draft
07.07.14 Updated draft based on Project
Steering Committee comments
S. Lang K.
Austin
K. Austin
Final
04.08.14 Final, based on further Project
Steering Committee comments
S. Lang K.
Austin
K. Austin
Final
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Options Evaluation and Indicative Costing
Executive Summary
Water security for Wangaratta has been a topical issue for several years, and assumed a
particularly high profile during the millennium drought and when 2003 bushfires affected the
water quality of the Ovens River. In 2013, the Victorian Government announced funding for
the Water Security for Wangaratta Project to assess the demand for water in Wangaratta,
and consider the best option for improving water security.
This first phase of the project estimated that the reliability of Wangaratta’s water supply is
88%, assuming current demands and operating rules, and historic climate conditions. That is,
there will be restrictions in 12% of years (or on average a 12% likelihood of restrictions in any
one year). This does not meet North East Water’s level of service objective of 90% reliability.
The first phase of the project also investigated several options to improve Wangaratta’s
reliability of supply:

The use of groundwater as a regular supplement to surface water supplies

The enlargement of Lake Buffalo by 10 GL (from 24 GL to 34 GL)

The use of alternative water sources, such as those identified in North East Water’s
Alternative Water Atlas (NEW, 2012)
This project forms part of phase two of the Water Security for Wangaratta project. The
objective was to undertake a more detailed analysis of the options listed above, and
recommend which of them would provide the most benefits, with the least negative impacts,
for the best value for money.
To do this, concept designs of the three options were completed, and their costs, benefits
and impacts were compared using a triple bottom line (TBL) assessment. The options were
designed with the aim of providing 90% reliability of supply to Wangaratta under a “return to
dry climate” and future (2060) demand scenario. The return to dry climate represents a
repeat of climate conditions experienced from 1997/98 to 2008/09.
The concept design for the additional groundwater use option involves upgrading the water
treatment infrastructure at NEW’s Kerr Street site, and installing two new bores with
associated water treatment infrastructure. The first would be located at NEW’s Phillipson
Street site. Three options were considered for the location of the second new bore, and the
preferred location was Cruse Street (near Kerr Street).
Final
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Options Evaluation and Indicative Costing
The concept design for enlarging Lake Buffalo involves raising the main and secondary
embankments by 3.8 m, upgrading the existing primary and secondary spillways, installing a
tertiary spillway, installing a new high level outlet, and placing filters in the secondary
embankment. The dam would become a fixed crest rather than gated storage, and the full
supply level would rise by 2.9 m.
During the concept design for the alternative water use option, several potential water
sources were considered, including treated trade waste, storm water and effluent from
Wangaratta’s waste water treatment plant (WWTP). Recycling effluent from the WWTP to
Class A standard, and using it to meet up to 700 ML of industrial, commercial and
Wangaratta City Council demands, and 250 ML of non-potable residential demands, was
found to be the most viable option. The concept design therefore involves a Class A water
treatment plant and a distribution system for the recycled water.
Table Error! No text of specified style in document..1 summarises the estimated capital
and operating costs, and net present value, for these three options. Although not included in
the concept design, the additional groundwater use option may also need a ‘stand-alone’
treatment plant for groundwater to be built at the Faithfull Street Water Treatment Plant
(WTP). This would cost an extra $1.5 - 2.0 million. Similarly, although not included in the
concept design, an enlarged Lake Buffalo may need a new intake tower and outlet
arrangement at an extra cost of $20 - $25 million, and a fish ladder at an additional cost of at
least $5 million.
Table Error! No text of specified style in document..1 : Indicative costs
Option
Estimated
capital cost
Estimated
additional
operating cost
Net present
value
Additional groundwater use
$15 million
$260,000*1
$17 million^
Enlarge Lake Buffalo
$80 million
$0*2
$54 million*3
Alternative water use
Notes:
$95 million
$1,000,000*1
$86 million*4
1 for return to dry climate scenario
2 relative to current operating costs
3 accounts for avoided future dam safety upgrades
4 accounts for avoided costs in developing additional agricultural re-use schemes
For the TBL assessment, each option was scored against financial, environmental, social and
technical criteria which were selected and weighted in consultation with the Project Steering
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Options Evaluation and Indicative Costing
Committee. Based on the adopted criteria, additional groundwater use is the highest ranking
option (Figure Error! No text of specified style in document..1). Enlarging Lake Buffalo and
alternative water use have similar, but much lower TBL scores.
The ranking of additional groundwater use as the best option was not sensitive to the
weighting of each criterion. For example, the cost drives much of the difference between the
TBL score for each option. However, even if financial criteria were excluded, groundwater
remained the highest ranked option (Figure Error! No text of specified style in
document..2). One reason for this is the additional groundwater use option scored highest
on the resilience criterion, because it is a climate independent source of water, and it is not
affected by events which may reduce surface water quality (e.g. bushfires and floods).
Enlarging Lake Buffalo scored the lowest totals on the environmental and technical criteria,
and similarly to the alternative water use option on the social and financial criteria. The large
scale of capital investment required to deliver the project was somewhat off-set by the
expected third party benefits to irrigators. However the complexity of the works, their impact
on terrestrial flora and fauna, and the anticipated price impact for irrigators also contributed to
the low TBL score. The large cost of capital works for the alternative water use option also
contributed to its relatively low score compared with groundwater. In addition, this option is
not expected to reduce the demand for potable water enough to achieve 90% reliability of
supply for Wangaratta under return to dry climate scenarios. Potential users of recycled water
will also need to be incentivised to switch over from their current potable water supply.
In summary, the use of additional groundwater was assessed as the option most likely to
improve water security for Wangaratta, and provide the best value for money with the least
negative impacts.
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Options Evaluation and Indicative Costing
TBL assessment scores
0
-20
The Base Case (Option 1)
-40
Additional Groundwater Use
(Option 2)
Enlarge Lake Buffalo (Option 3)
-60
-80
Alternative Water Use (Option 4)
-100
-120
-140
-160
-180
-200
Figure Error! No text of specified style in document..1 : The TBL assessment score for each option (relative
to a base case score of 0)
The graph illustrates the TBL assessment score for each option. The Base Case (Option 1)
has a score of 0; Additional Groundwater Use (Option 2) has a score of minus 21; Enlarge
Lake Buffalo (Option 3) has a score of minus 143; and Alternative Water Use (Option 4) has
a score of minus 188.
Non-financial (0/40/40/20)
60
The Base Case (Option 1)
40
20
0
Additional Groundwater Use
(Option 2)
Enlarge Lake Buffalo (Option 3)
Alternative Water Use (Option 4)
-20
-40
-60
-80
Figure Error! No text of specified style in document..2 : The TBL assessment score for each option, excluding
financial criteria
The graph illustrates the non-financial TBL assessment score for each option, excluding
financial criteria. The Base Case (Option 1) has a score of 0; Additional Groundwater Use
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Options Evaluation and Indicative Costing
(Option 2) has a score of between 35 and 40; Enlarge Lake Buffalo (Option 3) has a score of
between minus 60 and minus 70; and Alternative Water Use (Option 4) has a score of
between minus 35 and minus 40.
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