Barmah Choke Study - MDBA

Barmah Choke Study

INDIVIDUAL OPTIONS PHASE

Final

14 April 2011

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Barmah Choke Study

INDIVIDUAL OPTIONS PHASE

Final

14 April 2011

Sinclair Knight Merz ABN 37 001 024 095 452 Flinders Street, Melbourne, VIC, 3000 PO Box 312, Flinders Lane, Melbourne, VIC, 8009 Malvern VIC 3144 Australia Tel: +61 3 8668 3000 Fax: +61 3 8668 3001 Web: www.skmconsulting.com

LIMITATION: This report has been prepared on behalf of and for the exclusive use of Sinclair Knight Merz Pty Ltd‟s Client, and is subject to and issued in connection with the provisions of the agreement between Sinclair Knight Merz and its Client. Sinclair Knight Merz accepts no liability or responsibility whatsoever for or in respect of any use of or reliance upon this report by any third party.

Barmah Choke Study – Individual Options Phase

SINCLAIR KNIGHT MERZ PAGE i

Preface

This report contains the results of the Individual Options Phase (Phase 3) of the Barmah Choke

Study. In that phase, a comprehensive list of 17 identified options and their sub-options were

modelled and assessed. The development of options associated with Mulwala Canal has included

input from Murray Irrigation Limited.

The Phase 3 assessment results were framed around the relative performance of options in terms of

their potential effectiveness, cost and risk. Please note that, in Phase 3, the assessment focuses on

the technical capability of each option, on its own, to address the issues associated with the Barmah

Choke. A key finding of Phase 3 is that no single option adequately addresses all of the issues;

therefore it is now necessary to move to Phase 4 to investigate the better performing options in

combination.

The outcome of Phase 4 will be a „preferred package‟ of options for managing the issues associated

with the Barmah Choke. Any significant elements of the „preferred option package‟ will be subject

to further assessment, including giving greater attention to social and economic factors, prior to

proceeding with implementation.


SINCLAIR KNIGHT MERZ PAGE ii

Executive Summary

The Barmah Choke is a relatively narrow section of the River Murray through the Barmah-Millewa

Forest. The limited capacity of the Barmah Choke contributes to several operational and policy

challenges related to transferring water from upstream to downstream of the Barmah Choke.

The aim of the Barmah Choke Study is to develop an understanding of current and potential future

water supply and environmental risks associated with the Barmah Choke and other mid-river

operational issues. The study considers options, with the aim of identifying a preferred option, or

option packages, for reducing the impact of these issues while recognising that the Barmah Choke

performs an important role in flooding the Barmah-Millewa Forest.

Barmah Choke Study Objectives:

1) Reduce the incidence and magnitude of undesirable (generally unseasonal) watering of the

Barmah-Millewa Forest, thereby improving the health of the forest, and conserving water by

reducing losses.

2) Reduce the incidence and magnitude of shortfalls and rationing of diversions arising from

insufficient channel capacity for bulk water transfer to Lake Victoria.

3) Reduce the incidence and magnitude of shortfalls and rationing of diversions due to

insufficient channel capacity to meet demand during periods of peak irrigation usage and

during periods of high losses downstream of the Barmah Choke.

4) Enable flexibility to delay transfer of water from the upper Murray storages to Lake Victoria in

order to maximise conservation of water resources.

5) Provide capacity for the delivery of water trade from upstream of the Barmah Choke to

downstream of the Barmah Choke.

6) Improve the efficiency of delivering water to the icon sites.

In working toward the above objectives, future stages of the Barmah Choke Study will:

a) Maintain the beneficial influence of the Barmah Choke on the flooding regime of the Barmah-

Millewa Forest.

b) Identify any significant impacts on the frequency and magnitude of environmental and

unregulated flows in the River Murray System, with the aim to minimise these where possible.

c) Identify any significant impacts to other areas or to third parties, with the aim to minimise

these wherever possible.


SINCLAIR KNIGHT MERZ PAGE iii

The Barmah Choke Study comprises four phases as shown in Figure 1:

Discovery Phase (Phase 1) (completed)

Investigation Phase (Phase 2) (completed)

Individual Option Phase (Phase 3) (current phase)

Options Integration Phase (Phase 4) (next phase).

Figure 1 Phases of the Barmah Choke Study.

The “Individual Options Phase” of the Barmah Choke Study builds upon the outputs of the

previous phases. A range of operational, policy and structural river management options shortlisted

in the previous phase are described, modelled and assessed individually. This has led to a refined

shortlist of options and recommendations on option packages for modelling and assessment in the

next phase (Phase 4).

Hydrological modelling of the options has been undertaken using MSM-Bigmod, the Murray-

Darling Basin Authority‟s combined hydrological model, which is used to simulate flow and

salinity within the Murray and Lower Darling River Systems. The model contains 114 years of

flow and climate data and has been validated against recorded data. The model is used to inform

policy development and decision making within the MDBA. It represents the current situation,

including existing infrastructure and operating arrangements, and can be used to simulate the

impact of potential or expected future conditions.

A range of options have been selected for investigation, which include changes to the way existing

infrastructure is operated or could be enhanced through construction of, for example, new

regulators or channels. These options have been individually modelled using MSM-Bigmod where

appropriate. This involved making changes to the model to represent an option, for example,

increasing the capacity of an escape or lowering the target level of a weir.

Discovery Phase(Project Plan)

Investigations

PhaseConstraints, scenarios,

problem definition &

options identification

Report

Hold

point

Hold point

Model & assess options individually, then in

combination, and recommend ‘preferred option/s’

Individual Options

PhaseModelling & Assessment

Report

Options

Integration PhaseModelling & Assessment

Report

RMS Operations Review Project

Outputs

‘Preferred Option Development’


SINCLAIR KNIGHT MERZ PAGE iv

The range of options to reduce or eliminate the issues associated with the limited capacity of the

Barmah Choke can be grouped into a number of broad categories:

bypass capacity options: includes consideration of new bypasses, increasing the capacity of

existing bypasses, new escapes or increasing the capacity of existing escapes that would enable

water to be diverted around the Barmah Choke to reduce unseasonal flooding or to supply peak

demands

upper system storage options targeting unseasonal flooding: includes consideration of new

storages or modifications to existing storages upstream of the Barmah Choke that would allow

re-regulating unregulated flows (including rainfall rejections) to reduce unseasonal flooding

lower system storage options targeting shortfalls: includes consideration of new storages or

modifications to existing storages downstream of the Barmah Choke that provide flexibility to

meet peak irrigation demands

policy options: includes consideration of new policies or modifications to existing policies and

operational rules that would enable the River Murray System to be managed within the limited

capacity of the Barmah Choke without structural (construction) changes.

The following schematic diagrams (Figures 2 to 5), which are aligned to the broad categories

outlined above, provide a summary of the range of options and how they relate to the River Murray

System.

Figure 2: Schematic diagram of the River Murray System showing the location of bypass options. Bracketed numbers and letters refer to the option numbers.

Tocumwal

Mulwala Canal

Lake Mulwala Lake Hume

BARMAH CHOKE

Barmah-Millewa Forest

The DropEdward River

Wakool River

Murray River

GunbowerKoondrook-Perricoota

Forests

NSW-VIC-SA Border

Murray Mouth and Lower Lakes

Campaspe River

Tuppal & BullataleCreeks

Goulburn River

Broken Creek

Lake Eildon

Torrumbarry Weir

Goulburn Weir

Lake Victoria

Yarrawonga Main Channel

Dartmouth Reservoir

Mitta Mitta River

Murrumbidgee River

Menindee Lakes Storage

Darling River

Werai ForestEuston Weir

Lake Boga

Snowy Mountains

SchemeBillabong Creek

Loddon River

Finley Escape

Picnic Point

Kiewa River

Ovens River

Note:Schematic not to scale and does not show all weirs.

Edward Escape

Wakool River (11)(bypass route)

Edward River (12,a,b,c)(bypass route)

Bullatale Creek (9)(bypass route)

Victorian Forest Channels (10)(bypass route)

Broken Creek (13)(bypass route)

Barmah Bypass Channel (14)(indicative route)

Interconnector Channel (15)(indicative route)

Perricoota Escape (16,a,b,c)

(proposed bypass route)


SINCLAIR KNIGHT MERZ PAGE v

Figure 3: Schematic diagram of the River Murray System showing the location of upper system storage options targeting unseasonal flooding. Bracketed numbers and letters refer to the option numbers.

Figure 4: Schematic diagram of the River Murray System showing the location of lower system storage options targeting shortfalls. Bracketed numbers and letters refer to the option numbers.

Tocumwal

Mulwala Canal


BARMAH CHOKE



Wakool River

Murray River


Forests

NSW-VIC-SA Border


Campaspe River


Goulburn River

Broken Creek

Lake Eildon

Torrumbarry Weir

Goulburn Weir

Lake Victoria


Dartmouth Reservoir

Mitta Mitta River

Murrumbidgee River


Darling River


Lake Boga

Snowy Mountains


Loddon River

Finley Escape

Picnic Point

Kiewa River

Ovens River


Edward

Escape

The Drop (7a,b,c,d)(new storage)

Lake Mulwala (5a,b)(revised operation)

Tocumwal

Mulwala Canal


BARMAH CHOKE



Wakool River

Murray River


Forests

NSW-VIC-SA Border


Campaspe River


Goulburn River

Broken Creek

Lake Eildon

Torrumbarry Weir

Goulburn Weir

Lake Victoria


Dartmouth Reservoir

Mitta Mitta River

Murrumbidgee River


Darling River


Lake Boga

Snowy Mountains


Loddon River

Finley Escape

Picnic Point

Kiewa River

Ovens River


Edward Escape

Mildura Weir (4a,b)(revised operation)

Euston Weir (6a,b,c)(revised operation)

Mid-River Storage (8)(current operation)

Combined Weirs (17)(revised operation)


SINCLAIR KNIGHT MERZ PAGE vi

Figure 5: Schematic diagram of the River Murray System showing the location of policy options. Bracketed numbers and letters refer to the option numbers.

The approach adopted to evaluate options aimed to provide pertinent information required to

support and inform decision making. There were three aspects to the assessment:

1) use the hydrological models to assess the performance of the options with respect to a range of

indicators, including those related to flooding and flow delivery

2) obtain cost estimates for each option; this included both capital costs and operating costs

3) undertake a risk assessment that examined: technical feasibility, regulatory conditions,

stakeholder and community issues, demand and supply risk, environmental impact,

construction risk and operation risk.

All risks have been assessed on an unmitigated basis to aid comparison. It is acknowledged that

most (if not all) risks identified could be mitigated to an acceptable level through additional

planning, investigations or management actions but this may require a commitment of resources or

political capital by the MDBA and possibly the jurisdictions. These additional activities to reduce

risk have not been costed.

The three assessment aspects were combined to define each option such that a recommendation

could be made about their suitability for further investigation. Using this approach, recommended

options are those which combine effectiveness, acceptable cost and acceptable risk. Additional

information on the effectiveness, cost and risk of individual options can be found in Sections 6, 4

and 5 respectively.


SINCLAIR KNIGHT MERZ PAGE vii

Figure 6 summarises the impact of options on the significance of the problem in terms of the

incidence of shortfalls and unseasonal flooding. Figure 6 also indicates the relative cost and highest

risk category of each option. Additional details for each option are listed in Table 1. In the

discussion that follows broad categories of costs are used: low (less than $5 million), moderate

(between $5 million and $20 million) and high (more than $50 million).

Table 1 Option summary assessments- key finding, green highlighting indicates options of higher potential

Option Summary assessment

Option 1- do nothing The base case

Option 2- alter the 6-inch rule to increase operational flexibility

Limited effectiveness

Option 3a- policy options to manage within the capacity of the Barmah Choke: Lake Victoria transfers

Moderately effective at low cost

Option 3b- policy options to manage within the capacity of the Barmah Choke: inter-valley trade


Option 3c- policy options to manage within the capacity of the Barmah Choke: non-asset solutions

Use of environmental entitlements has potential to be an efficient and effective way of reducing the impacts of shortfalls as well as reducing total shortfalls altogether. The way in which environmental entitlement holders utilise their entitlement could have a significant impact on management of the Barmah Choke

Option 4- increased operational flexibility in existing assets: Mildura Weir

a) minimum operating level lowered by 1 m

b) minimum operating level lowered by 2 m

Low cost and highly effective but similarly effective options are of lower cost

Option 5- lower typical operating level in Lake Mulwala

a) by 0.1 m

b) by 0.5 m

Option 5b is highly effective but high risk and moderate cost. Option 5a, is less effective than Option 5b, but is lower risk and low cost

Option 6- enlarged storage capacity in Euston Weir

a) maximum operating level raised by 0.5 m

b) minimum operating level lowered by 1.5 m

c) maximum operating level raised by 0.5 m and minimum operating level lowered by 1.5 m

Low cost and highly effective. Other weir options (Option 4 and Option 17) are similarly effective

Option 7- storage at “The Drop” on Mulwala Canal

a) storage capacity of 1 GL

b) storage capacity of 5 GL

c) storage capacity of 11 GL

d) storage capacity of 16 GL

Smaller volume options are moderately effective but of moderate cost, larger volume options are highly effective but of high cost

Option 8- construction of a mid-river storage Not assessed because mid-river storage is already operational

Option 9- Bullatale Creek bypass Not assessed: would require significant works in a National Park which means this option is not likely to be appropriate

Option 10- Victorian forest channels Moderately effective but high risk and high cost


SINCLAIR KNIGHT MERZ PAGE viii


Option 11- increased escape capacity to the Wakool River

Limited effectiveness, moderate cost

Option 12- Increased escape capacity to the Edward River

a) additional 800 ML/day capacity

b) additional 1,500 ML/day capacity

c) additional 2,000 ML/day capacity

Moderately effective, moderate cost

Option 13- Increased escape capacity to Broken Creek


Option 14- Barmah bypass channel Not assessed: a large, high cost channel in close proximity to the Barmah Forest National Park. A high risk, high cost option

Option 15- Murray-Goulburn interconnector channel Highly effective but high risk and high cost

Option 16- Perricoota Escape

a) use existing additional capacity (200 ML/day)

b) additional 500 ML/day capacity


Limited effectiveness (Option 16a – low cost, Option 16b – moderate cost, Option 16c – high cost)

Option 17- Combined weir manipulation Highly effective low cost


SINCLAIR KNIGHT MERZ PAGE ix

Figure 6: The position of the points on each axis shows the effectiveness of options for reducing the incidence of shortfalls and unseasonal flooding; with the size of the point indicating the cost; and the colour the highest risk category for the option.

There are key findings that stand out from the plot of the results:

weir options (Option 4b, Option 6c and Option 17) are effective, low cost and significant risk

approaches to reducing shortfalls

there are no low cost, low risk options that are highly effective at reducing forest flooding

(Option 5b is high risk, Option 7d and 7c are high cost and Option 10 is both high cost and

high risk).

Bypass options involving Mulwala Canal (particularly Option 12c) are moderately effective at

reducing both shortfalls and unseasonal flooding


SINCLAIR KNIGHT MERZ PAGE x

The best way forward on forest flooding would be to assess the performance of Option 5a

combined with Option 12c. The effectiveness of Option 5a and Option 7b are similar but

Option 12c is of lower cost than Option 7b.

A selection of options were modelled using three future scenarios (drier climate, post-TLM, and a

combined drier climate and post-TLM) to test the robustness of their performance. The scenario

results demonstrate that the frequency and severity of simulated shortfall events are dependent on a

number of factors. A major driver is tributary inflows over the summer period when shortfalls are

most likely to occur. Changes to irrigation demands (via change allocation due to different inflows)

also impact the results but this impact appears to have less of an effect on shortfalls than the

volume and pattern of tributary inflows downstream of Barmah Choke.

Options that involve drawing on storage downstream of the Choke have been shown to be very

effective in the three scenarios modelled.

The incidence and magnitude of unseasonal flooding is also dependent on inflows, with the dry

climate change to 2030 scenario dramatically reducing the number of unseasonal flood events,

while the post-TLM scenario increased the number of unseasonal flood events. Of the options

modelled for the scenarios which reduced unseasonal flooding, the most effective option was the

largest storage option (Option 5b) which had approximately 21 GL of active airspace. Under the

three scenarios this was still the case.

Based on the options assessment, a number of packages of options were developed (see Section 8).

From this it is recommended that the best package of options to take forward combines the

following options:

Better use of weirs downstream of the Barmah Choke to address shortfalls (a combination of

Options 4b, 6c, and 17)

Increased bypass capacity through the Mulwala Canal (Option 12c)

Allow lower (100 mm) typical operating level for Lake Mulwala (Option 5a).

Additional packages of options that may meet other criteria of the MDBA or the States (such as

those that are low cost or those able to be implemented quickly) are listed in the main report.

The results also suggest some options that can be ruled out. These are the options considered to be

inferior relative to other options being assessed. That is, there are many situations where other

options are better (more effective, less costly and less risky) and no situations where the inferior

option is better. Additionally, some options can be ruled out because they are simply too costly,

risky and lack effectiveness. The rationale for not proceeding with these options can be found in

Section 8.1. Overall, we suggest the following options are not considered further as part of the

Barmah Choke Study:


SINCLAIR KNIGHT MERZ PAGE xi

Option 2: Alter the 6-inch rule to increase operational flexibility

Option 9: Bullatale Creek bypass

Option 10: Victorian Forest Channels

Option 14: Barmah bypass

Option 15: Murray-Goulburn interconnector channel.

No single option adequately addresses all of the issues; therefore it is necessary to investigate

options in combination. The fourth and final phase of the Barmah Choke Study will review the

outputs of the Individual Options Phase (Phase 3) in an integrated manner to identify and assess

potential option packages.

It is anticipated that the final outcome of the Barmah Choke Study, around late 2011, will be a

recommendation of preferred option packages. Following this, the MDBA and partner governments

will decide what further analysis and consultation is needed and whether to proceed with detailed

designs, construction and/or implementation of a range of options.


SINCLAIR KNIGHT MERZ PAGE xii

List of acronyms and abbreviations

AHD Australian Height Datum

CEWH Commonwealth Environmental Water Holder

DEWHA (former) Department of Environment, Water Heritage and the Arts

EIS Environmental Impact Statement

EPBC Environmental Protection and Biodiversity Conservation (Act)

EVA End of Valley Account

G-MW Goulburn-Murray Water

ISO International Standards Organisation

IVT Inter-Valley Trade

MDB Murray-Darling Basin

MDBA Murray-Darling Basin Authority

MDBC (former) Murray-Darling Basin Commission

MIL Murray Irrigation Limited

MSM Murray Simulation Model

NSW New South Wales

NVIRP Northern Victoria Irrigation Renewal Project

NWC National Water Commission

OH&S Occupational Health and Safety

PRIDE Program for Regional Irrigation Demand Estimation

SDL Sustainable Diversion Limit

SEWPaC (Department of) Sustainability, Environment, Water, Population and Communities

SKM Sinclair Knight Merz

TLM The Living Murray

RMW (former) River Murray Water, now River Murray Division within the Authority

A glossary has also been prepared and is provided at the end of this report.


SINCLAIR KNIGHT MERZ PAGE xiii

Contents

Executive Summary i

List of acronyms and abbreviations xii

1. Introduction 1

1.1. What is the Barmah Choke? 1

1.2. Objectives of the Barmah Choke Study 2

1.3. Barmah Choke Study Phasing 3

1.4. Objectives of this phase of the Barmah Choke Study 4

2. Option assessment method 5

2.1. Selecting the assessment method 5

2.2. Applying the assessment method 7

3. Options review 11

3.1. Option 1: „do nothing‟ 13

3.2. Option 2: alter 6-inch rule to increase operational flexibility 15

3.3. Option 3a: policy options to manage within the capacity of the Barmah Choke- Lake Victoria Transfers 20

3.4. Option 3b: policy options to manage within the capacity of the Barmah Choke- inter-valley trade 24

3.5. Option 3c: policy options to manage within the capacity of the Barmah Choke- non-asset solutions 29

3.6. Option 4: increased operational flexibility in existing assets: Mildura Weir 31

3.7. Option 5: lower operating level in Lake Mulwala 35

3.8. Option 6: enlarged storage capacity in Euston Weir 39

3.9. Option 7: storage at “The Drop” on Mulwala Canal 44

3.10. Option 8: construction of a mid-river storage 48

3.11. Option 9: Bullatale Creek bypass 51

3.12. Option 10: Victorian forest channels 55

3.13. Option 11: increased escape capacity to the Wakool River 59

3.14. Option 12: increased escape capacity to the Edward River 62

3.15. Option 13: increased escape capacity to Broken Creek 66

3.16. Option 14: Barmah bypass channel 69

3.17. Option 15: Murray-Goulburn interconnector channel 72

3.18. Option 16: Perricoota Escape 76

3.19. Option 17: combined weir manipulation 79

4. Option costing and risk cost analysis 82

4.1. Option costing 82


SINCLAIR KNIGHT MERZ PAGE xiv

4.2. Assessment process 83

4.3. Summary of results 85

4.4. Limitations 87

4.5. Costing of additional options 87

5. Option risk assessment 88

5.1. Risk assessment process 88

5.2. Risk assessment context 88

5.3. Risk assessment results 90

5.4. Option key risk summary and mitigation 107

6. Option modelling 112

6.1. Summary of modelling methods 112

6.2. Evaluation of option effectiveness 113

6.3. Significance of the problem under the base case 114

6.4. Option evaluation 116

7. Scenarios 125

7.1. Upper system options targeting unseasonal flooding 126

7.2. Lower system storage options targeting shortfalls 127

7.3. Summary of outcomes from scenario modelling 128

8. Option package recommendations 130

8.1. Options that can be ruled out 131

8.2. Low investment options 131

8.3. Options that can be implemented quickly 131

8.4. Options to address forest flooding 132

8.5. Options to address shortfalls 132

8.6. Options with the largest environmental benefit 132

8.7. Options shared between New South Wales and Victoria 133

8.8. Best performance 133

8.9. The works 134

8.10. Other considerations 134

9. Conclusions 135

10. References 139

Glossary 143

Appendix A Detailed review of Option 3c 145

Appendix B Option modelling methods 154

Appendix C Calculation of the significance of the problem 208


SINCLAIR KNIGHT MERZ PAGE xv

Appendix D Option modelling results summary 228

Appendix E Scenario modelling results summary 233

Appendix F Financial analysis of options 240


SINCLAIR KNIGHT MERZ PAGE xvi

Document history and status

Revision Date issued Reviewed by Approved by Date approved Revision type

Draft A 19/11/2010 T Ladson

T Sheedy

R Molloy 22/11/2010 Draft A

Final 03/02/2011 T Ladson

T Sheedy

R Molloy

R Molloy 03/02/2011 Final

Final 12/04/2011 R Molloy R Molloy 14/04/2011 Final (edited in response to MDBA comments)

Distribution of copies

Revision Copy no Quantity Issued to

Draft A 1 Electronic MDBA (Lindsay White, Sarah Commens)

Final 1 Electronic MDBA (Lindsay White, Sarah Commens)

Final 1 Electronic MDBA (Joe Davis, Sarah Commens)

Printed: 30 June 2011

Last saved: 30 June 2011 05:33 PM

File name: I:\VWES\Projects\VW04951\Technical\5_Task 5 Reporting\R04_IndividualOptionsReport_Final (14Apr11).docx

Author: Erin Murrihy, Tony Sheedy, Tony Ladson, Dan Beasley, Andrew Herron

Project manager: Rob Molloy

Name of organisation: Murray-Darling Basin Authority

Name of project: Barmah Choke Study

Name of document: Individual Options Phase

Document version: Final

Project number: VW04951

Barmah Choke Study – Individual Option Phase

SINCLAIR KNIGHT MERZ PAGE 1

1. Introduction

1.1. What is the Barmah Choke?

The term „Barmah Choke‟ is used to describe the relatively narrow section of the River Murray

through the Barmah-Millewa Forest. In comparison to other nearby sections, the operating

capacity (near bankfull) of the Barmah Choke is small: approximately 8,000 ML/day at the

downstream end of the Barmah-Millewa Forest. Figure 1-1 shows a schematic diagram of the

River Murray System from Dartmouth Reservoir to the South Australia border, indicating the

location of the Barmah Choke.

Figure 1-1: Schematic diagram of the River Murray System.

The Barmah Choke contributes to a number of operational and policy challenges in the River

Murray System, including:

1) delivery of sufficient water to the lower Murray to meet peek irrigation demands

2) delivery of sufficient water to Lake Victoria to supply South Australia

3) management of rainfall rejection1 events that can lead to unseasonal flooding of the


4) delivery of future environmental flows

5) constraints on the trade of water.

1 Rainfall rejections occur when a combination of reduced irrigation demands (due to rain over the

irrigation areas) and increases in inflows from unregulated tributaries lead to increased flows in the

River Murray. River levels may rise and exceed the capacity of the Barmah Choke, flooding the

Barmah-Millewa Forest (MDBC, 2008).

Tocumwal

Mulwala Canal


BARMAH CHOKE



Wakool River

Murray River


Forests

NSW-VIC-SA Border


Campaspe River


Goulburn River

Broken Creek

Lake Eildon

Torrumbarry Weir

Goulburn Weir

Lake Victoria


Dartmouth Reservoir

Mitta Mitta River

Murrumbidgee River


Darling River


Lake Boga

Snowy Mountains


Loddon River

Finley Escape

Picnic Point

Kiewa River

Ovens River


Edward

Escape



These operating challenges are not entirely attributable to the Barmah Choke, particularly

those where meeting peak irrigation demands requires long travel times, but may be

exacerbated by the constraints posed by the Barmah Choke.

1.2. Objectives of the Barmah Choke Study

The Barmah Choke Study aims to understand current and potential future water supply and

environmental risks and opportunities associated with the Barmah Choke and other mid-river

operational issues. The study will consider options for reducing the impact of these issues

while recognising that the Barmah Choke performs an important role in flooding the Barmah-

Millewa Forest; a Living Murray icon site incorporating two Ramsar listed sites (the Barmah

Forest in Victoria and the Central Murray Forests in New South Wales).

The Barmah Choke Study seeks to identify a preferred option, or package of integrated

options, which meet a number of objectives as outlined in the following box.

Objectives:

1) Reduce the incidence and magnitude of undesirable (generally unseasonal) watering of the

Barmah-Millewa Forest, thereby improving the health of the forest, and conserving water

by reducing losses.

2) Reduce the incidence and magnitude of shortfalls and rationing of diversions arising from

insufficient channel capacity for bulk water transfer to Lake Victoria.

3) Reduce the incidence and magnitude of shortfalls and rationing of diversions due to

insufficient channel capacity to meet demand during periods of peak irrigation usage and

during periods of high losses downstream of the Barmah Choke.

4) Enable flexibility to delay transfer of water from the upper Murray storages to Lake

Victoria in order to maximise conservation of water resources.

5) Provide capacity for the delivery of water trade from upstream of the Barmah Choke to

downstream of the Barmah Choke.

6) Improve the efficiency of delivering water to the icon sites.

In working toward the above objectives, future stages of the Barmah Choke Study will:

a) Maintain the beneficial influence of the Barmah Choke on the flooding regime of the

Barmah-Millewa Forest.

b) Identify any significant impacts on the frequency and magnitude of environmental and

unregulated flows in the River Murray System, with the aim to minimise these where

possible.

c) Identify any significant impacts to other areas or to third parties, with the aim to minimise

these wherever possible.



1.3. Barmah Choke Study Phasing

The Barmah Choke Study comprises four phases as shown in Figure 1-2:

Discovery Phase (Phase 1) (completed)

Investigation Phase (Phase 2) (completed)

Individual Option Phase (Phase 3) (current phase)

Options Integration Phase (Phase 4) (next phase).

Figure 1-2: Phases of the Barmah Choke Study.

The Discovery Phase was completed in December 2007 and resulted in the preparation of the

Barmah Choke Study Project Plan (SKM, 2007).

The Investigation Phase was completed in July 2009 (SKM, 2009). The Investigation Phase

developed indicators to assess options and defined the magnitude of the problems associated

with the Barmah Choke under the base case. The Investigation Phase found that the limited

capacity of the Barmah Choke currently restricts the ability of the River Murray System to

meet the demands of irrigators and other water users and to manage high summer flows

through the Barmah-Millewa Forest. This can contribute to rationing or restrictions on supply

to Torrumbarry and Sunraysia irrigation areas and may restrict supply of South Australia‟s

entitlement. There are also local environmental issues such as unseasonal flooding which is

contributing to changes in forest vegetation communities of the Barmah-Millewa Forest

(SKM, 2009). The assessment found that these problems are likely to persist into the future,

including under climate change scenarios.

Discovery Phase(Project Plan)

Investigations

PhaseConstraints, scenarios,

problem definition &

options identification

Report

Hold

point

Hold point

Model & assess options individually, then in

combination, and recommend ‘preferred option/s’

Individual Options

PhaseModelling & Assessment

Report

Options

Integration PhaseModelling & Assessment

Report

RMS Operations Review Project

Outputs

‘Preferred Option Development’



A key output of the Investigation Phase was a list of options suitable for further investigation.

This phase of the Barmah Choke Study, the Individual Option Phase, builds upon the outputs

of the previous phases. It describes and reviews each of the options identified in the

Investigation Phase and models and assesses individually each option to determine its potential

to improve the management of the River Murray System by reducing or alleviating the issues

associated with the Barmah Choke.

1.4. Objectives of this phase of the Barmah Choke Study

The Individual Option Phase comprised five key tasks, each with a specific objective:

Task 1: Options review – review and describe each of the options identified as a part of

the Investigation Phase, plus additional options and variants of options (sub-options)

identified by the MDBA and other stakeholders

Task 2: Development of an option assessment method –based on interpretation of model

outputs and other pertinent information

Task 3: Options modelling – model each of the options identified as suitable for further

investigation (from Task 1) using MSM-Bigmod as appropriate

Task 4: Options assessment – assess the options modelled in Task 3 using the method

developed in Task 2

Task 5: Reporting – report on the key outcomes and findings of this phase (Individual

Options Phase) of the Barmah Choke Study and make recommendations for the Options

Integration Phase.

This report has been prepared as a part of Task 5 and documents the key outcomes and

findings of this phase of the Barmah Choke Study.



2. Option assessment method

2.1. Selecting the assessment method

An assessment method was selected to be appropriate for the data and time available following

consideration of established assessment methods. The approaches that were considered

included the following:

Cost-benefit analysis: where the full costs and benefits are quantified in a single standard

unit of measure, such as dollars in present day prices. This type of analysis aims to assess

the overall worth of a project from the perspective of the community irrespective of

whether there are „winners‟ and „losers‟. The best option would have the highest net

present value or cost-benefit ratio.

Cost-effectiveness analysis: this process outlines the costs of achieving a particular

outcome. Typically this process establishes the least cost method to achieve a particular

outcome.

Multi-criteria analysis: is a framework which allows options to be ranked or scored based

on the judged level of performance against a set of criteria. The criteria are usually

weighted to reflect their importance.

All methods are considered well founded and suited to assessment in the environmental

context. A selection process is outlined in Figure 2-1 (adapted from Hajkowicz, 2008).

Figure 2-1: Assessment selection process (adapted from Hajkowicz, 2008).



Following this process, the method chosen is largely dependent on the ability to evaluate

benefits in monetary or unit terms. In this case, the likely benefits (especially those relating to

changes to agricultural productivity due to reduced shortfalls and environmental benefits

relating to flood events) were difficult to quantify in monetary terms and a single unit for

assessing cost effectiveness was not available. As such, the most appropriate assessment

method for the Barmah Choke Study is a multi-criteria analysis.

The benefits of multi-criteria analysis include the ability to incorporate the views and

perceptions of a range of stakeholders and that it can be applied to complex problems which

include monetary and non-monetary terms. Key criticisms of multi-criteria analysis are the

subjectivity and arbitrariness in the process, particularly in relation to the assigning of weights

and criteria as well as the option scoring process.

For this phase of the Barmah Choke Study, an assessment was undertaken which provided the

data required for a multi-criteria analysis. The assessment involves consideration of three

aspects for each option:

1) modelling outputs and indicators (and their interpretation) as a measure of effectiveness

2) cost estimate

3) risk assessment

These aspects were combined to provide decision makers with the pertinent information

required and to define each option such that a recommendation could be made about their

suitability for further assessment. Using this approach, favourable options are those options

which combine effectiveness, acceptable cost and acceptable risk, as shown in Figure 2-2.

Note that the assessment process stopped short of completing the multi-criteria analysis (i.e.

the options were not ranked) as it was not necessary to rank options at this stage.



Figure 2-2: Selecting the favourable option(s).

2.2. Applying the assessment method

The process which has been applied to undertake the option assessment is shown in Figure 2-3.

A more detailed description of each process task is provided below.

Figure 2-3: Proposed assessment process.

Detailed modelling outputs for each option

The main indicators that have been used to evaluate the potential effectiveness of each option

is the option‟s ability to address the issues associated with the limited capacity of the Barmah

Choke, specifically, the impact of the option on the number of years with unseasonal flooding

Effective Options

Options of Acceptable

Cost

Options of Acceptable Risk

Favourable Option(s)



(and the extent of the forest flooded) of the Barmah-Millewa Forest and the number of years

with shortfalls.

The impact of the option on other issues associated with the Barmah Choke including the

delivery of environmental flows, the beneficial influence of the Barmah Choke for flooding of

the Barmah-Millewa Forest and other areas or third parties has also been considered though

the use of project specific indicators developed as a part of the Investigation Phase (SKM,

2009) (summarised in Table 2-1) and the suite of MDBA standard indicators (MDB A, 2010a)

as appropriate. A description of the modelling methods is provided in Section 6.1. See

Appendix C for more detail on the indicators. The expected impact of options on constraints

on water trade is also commented upon.

Table 2-1: Project specific indicators which may be used to assess option performance.

Objective Indicator

Conservation of water resources Key allocation statistics for general security (NSW) and high and low reliability (Victoria) entitlements

Beneficial influence of the Barmah Choke

Flooding regime of the Barmah-Millewa Forest percentage of years with small and large floods in the


maximum duration (in years) with no flood

Frequency and magnitude of environmental flows in the River Murray System: Frequency of key flooding criteria at key locations

(Koondrook/Gunbower, Hattah Lakes, Chowilla/Lindsay

Flows to South Australia Average flow to SA in excess of entitlement (GL/year)

% Years where flows to SA < 1850 GL/year

Significant impacts to other areas and third parties Maintain water levels in Lake Victoria and Menindee

Lakes for cultural heritage reasons

Avoid Werai Forest unseasonal flooding

Avoid undesirable exceedance of 25,000 ML/d downstream of Hume

Avoid undesirable exceedance of capacity of Edward and Gulpa offtakes

Maintain recreational water levels at lake Mulwala, Euston Weir

For each option, a summary of the modelling results relative to Option 1- „do nothing‟ (the

base case) has been prepared. This was based on the raw modelling and indicator outputs,

without interpretation of the impact.

Some options also required specific issues to be addressed. Where this is the case, the issues

have been explored using appropriate indicators and parameters and reported on.



Undertake financial assessment including risk cost analysis

The financial assessment incorporated cost estimation and risk cost analysis processes. The

cost estimates are preliminary and have been based on item unit costs which were estimated

based on the team‟s experience from a range of similar projects. This approach is the most

appropriate at this stage of the investigation. The preliminary nature of this analysis results in

cost estimates in the range of +/- 30% accuracy.

A risk cost analysis has also been undertaken on the cost estimates. This process aims to

provide a probabilistic estimation of cost based on known cost variation ranges. The process

works by developing a probability distribution of capital costs for each of the cost items (using

three points: low estimate, best estimate and a high estimate). A Monte Carlo simulation then

runs a process of selecting a cost estimate randomly from each cost item based on its

distribution and summing these to create a total cost estimate. This is repeated up to 10,000

times to create a probabilistic estimate of cost. The median and 90th percentile cost estimates

have been reported.

This analysis of capital costs is combined with any on-going costs, such as pumping, staff or

maintenance costs, have been combined to assess the life-cycle cost of each option using a

discounted cash flow method. The cost analysis is from the perspective of the MDBA (or

government in general) and includes the direct cash costs only, not the impacts to third parties

such as irrigators.

More details on the cost estimation and risk costs analysis process, along with a summary of

the cost estimates for each option is provided in Section 4.

Outline high level risks associated with options

A high level risk assessment has also been undertaken for each option. This assessment has

considered the high level risks associated with implementing each option. This stops short of a

complete implementation risk assessment but is suitable to compare options. The risk

assessment covered the following risk types:

technical feasibility- risk that the project will not be delivered or is technically infeasible

regulatory conditions- risk that the project will be subject to significant approvals

processes

stakeholder and community- risk that the project is subject to significant community or

stakeholder opposition

demand / supply risk- risk that changes to irrigation demand and supply conditions mean

that infrastructure is being used significantly less than designed for, and potentially

obsolete

environmental risk- risk that the project construction or operation is likely to cause

unacceptable environmental damage



construction cost risk- risk the project is likely to be subject to cost overruns

operation risk- risk relating to the operational requirements to implement and control the

option

The assessment was qualitative and used an evaluation of likelihood and consequence to

determine the risk level.

More detail on the risk assessment process along with a summary of the outcomes of the

assessment is included in Section 5.

Presentation of model interpretation

The results of the model interpretation process have been presented in a number of ways.

Initially, the results of the interpretation against each performance indicator is summarised in

table form as change in the indicator value from Option 1- do nothing and key findings from

these results are discussed.

Further communication of the results focuses on key outcomes. For each option the four most

important indicators are:

performance of the option in reducing shortfalls

performance of the option in decreasing unseasonal flooding

option risk

option cost.

Based on the findings of this assessment, recommendations have been made for packages of

options to meet specific objectives. It is expected that these recommendations will inform the

development of integrated option packages for the next phase of the Barmah Choke Study.

Monetising process or scoring and weighting process

While not proposed or necessary for this phase of the Barmah Choke Study, a cost-benefit

analysis or full multi-criteria analysis could be undertaken using the data gathered to date. For

a cost-benefit analysis, this would involve taking the description of impacts and „monetising‟

them. That is, assigning monetary values which will largely relate to changes in environmental

amenity and to productive changes associated with irrigation use otherwise not available due to

shortfalls. To complete a multi-criteria analysis, if required, a set of criteria and weights would

be agreed and a scoring process undertaken. Given the aims of this phase of the Barmah Choke

Study, undertaking multi-criteria analysis or cost-benefit analysis were not considered to

progress the overall Barmah Choke Study objectives in any meaningful way, nor would these

likely change the overall conclusions.



3. Options review

Options to reduce or eliminate the issues associated with the limited capacity of the Barmah

Choke have been grouped into a number of broad categories:

policy options

upper system storage options targeting unseasonal flooding

lower system storage options targeting shortfalls

bypass capacity options

Policy options may include new policies or modifications to existing policies and/or

operational rules. Such options are aimed at enabling the River Murray System to be managed

within the limited capacity of the Barmah Choke without structural changes.

System storage options may include either new storages or modifications to existing storages.

Upper system storage options are based on storage upstream of the Barmah Choke and are

aimed at re-regulating unregulated flows (including rainfall rejections) to reduce unseasonal

flooding, while lower system storage options are based on storage downstream of the Barmah

Choke and are aimed at providing flexibility to meet peak irrigation demands.

Bypass capacity options may involve increasing the capacity of one or more of the potential

bypasses or the capacity of an outfall to a bypass or a combination of both or may involve

construction of a new bypass around the Barmah Choke. Such options are aimed at enabling

water to be diverted around the Barmah Choke to reduce unseasonal flooding or to supply peak

demands.

The Discovery Phase of the Barmah Choke Study identified a preliminary list of 22 options.

The Investigation Phase reviewed each of these options in light of the outcomes regarding the

significance and magnitude of the problem. The review identified 15 options with the potential

to reduce or eliminate the issues associated with the Barmah Choke and suitable for further

investigation.

A workshop was held with the River Murray System Operations Review Working Group (30

March 2010) to review each option. A key outcome of this workshop was guidance on which

options should “progress” for individual modelling and assessment and which options should

be “parked” (not considered further) at this stage. The outcomes of this workshop are

summarised in Table 3-1.

Following the workshop two additional options were included: a bypass route utilising

Perricoota Escape (Option 16) and increased operational flexibility in multiple lower system

storages (in combination) (Option 17).



Table 3-1: Outcomes from the options review workshop 30 March 2010.

Option Status Comment

Option 1- do nothing Progress Base case option for comparison.


Progress


Progress


Progress Progression will consider a preliminary exploration of the potential for alternative rules and/or release patterns. Full optimisation will not be undertaken.


Progress Concept

Not a modelling option. Progression will identify the key issues that would need to be resolved before the option could be fully considered and developed.


Progress

Option 5- lower operating level in Lake Mulwala

Progress


Progress


Progress

Option 8- construction of a mid-river storage

Currently Operational

Whilst this option is currently operational, it is not included in the base case model. As such, this option has not been modelled at this stage but may be considered at a later stage.

Option 9- Bullatale Creek bypass Parked Parked as the proposed bypass route travels through a section of the Millewa National Park (established July 1 2010) and the works required along the bypass route may have a significant impact on the park which would be expected to be inappropriate.

Option 10- Victorian forest channels Progress


Progress


Progress


Progress

Option 14- Barmah bypass channel Parked Parked as this option is a large, very high cost channel in close proximity to the Barmah Forest National Park.

Option 15- Murray-Goulburn interconnector channel

Progress

Option 16- Perricoota Escape Progress

Option 17- Combined weir manipulation Progress



3.1. Option 1: „do nothing‟

Option description

The „do nothing‟ option represents the continuation of current demand and operating practices

into the future. It provides the base case, and other options must represent an overall

improvement from the „do nothing‟ option to be considered for implementation.

This option is based on the pre-TLM reference run scenario (MDBA, 2010) and represents pre-

TLM operating conditions with historical climate conditions.

Modelling outcomes and potential risks and opportunities

The base case or „do nothing‟ option was modelled as a part of the Investigation Phase (SKM,

2009) to establish base conditions against which the other options can be compared. During the

Investigation Phase it was found that the limited capacity of the Barmah Choke currently

restricts the ability of the River Murray System to meet the demands of irrigators and other

water users and to manage high summer flows through the Barmah-Millewa Forest.

The restricted ability to meet the demands of irrigators and other water users may result in

rationing of peak demands in Torrumbarry and Sunraysia and restrictions of supply to South

Australia. The restricted ability to manage high summer flows through the Barmah-Millewa

Forest is leading to changes in forest vegetation communities, threatening Moira Grass plains

and River Red Gums.

The Investigation Phase (SKM, 2009) also noted that the problems associated with the Barmah

Choke are likely to persist into the future, including under climate change conditions which are

expected to lead to:

increase in shortfalls, which may increase the frequency of demand rationing to

Torrumbarry and Sunraysia and restrictions on supply to South Australia due to the

differential impact of climate change on inflows across the River Murray System

reduction in the frequency and severity of unseasonal flooding, reducing the impact of

unseasonal flooding; however it is unlikely that the forest would return to natural

conditions, as the flood characteristics (volume and duration) would remain different

(lower peak volume and reduced duration) to those observed under natural conditions.

Note that, due to model improvements since the Investigation Phase, the base case has been re-

modelled for the Individual Option Phase and the base case conditions have been revised. The

revised base case conditions are presented in Section 6.3, however the re-modelling of the base

case has not led to a change in the key findings of the Investigation Phase as summarised

above.



Option 1: do nothing

Description

Option 1 represents the continuation of current demand and operating practices into

the future

this option provides a base case against which options must represent an overall

improvement to be further considered

Modelling outcomes

limited capacity of the Barmah Choke currently restricts the ability of the River Murray

System to meet the demands of irrigators and other water users and to manage high

summer flows through the Barmah-Millewa Forest. These issues are likely to persist

into the future

Potential risks and opportunities

risk the current issues will continue, or potentially worsen, into the future.



3.2. Option 2: alter 6-inch rule to increase operational flexibility

Option description

The 6-inch rule limits the rate of fall of river level at Doctors Point downstream of Hume

Reservoir to a maximum of 6-inches (150 mm) per day. This rule was “adopted to provide

adequate warning of river level changes, and to minimise bank slumping” (River Murray

Water, 2006) and is the most conservative „rate of fall‟ rule being applied in the Murray-

Darling Basin (Earth Tech, 2007). The location of Doctors Point where the 6-inch rule is

applied is shown in Figure 3-1.

Figure 3-1: Schematic diagram of the River Murray System showing the location of

Doctors Point where the 6-inch rule is applied.

The 6-inch rule limits the ability to respond to rapidly changing conditions in two ways:

may limit the rate of reduction or releases at the end of the irrigation season when demand

for water is rapidly decreasing

limits the rate of reduction of releases during rainfall rejection event.

Despite the conservatism imposed by the 6-inch rule, the exact origin of the selection of 6-

inches as the maximum drawdown rate is unknown, but it relates to concerns about bank

erosion and slumping. According to Nation and Ladson (2008) “The first mention of a 6-inch

drawdown limit at Doctors Point is in a letter from the River Murray Commission to the

Electricity Commission of New South Wales on 25 November 1955 in relation to operation of

a proposed power station at Hume Dam” (page 2).

In more recent years, the basis of the 6-inch rule has been questioned. Green (1999)

investigated river drawdown and bank stability, finding that bank erosion is the result of

Doctors Point(just downstream of

Kiewa River Confluence)

Tocumwal

Mulwala Canal


BARMAH CHOKE



Wakool River

Murray River


Forests

NSW-VIC-SA Border


Campaspe River


Goulburn River

Broken Creek

Lake Eildon

Torrumbarry Weir

Goulburn Weir

Lake Victoria


Dartmouth Reservoir

Mitta Mitta River

Murrumbidgee River


Darling River


Lake Boga

Snowy Mountains


Loddon River

Finley Escape

Picnic Point

Kiewa River

Ovens River


Edward Escape



numerous processes, not just drawdown. This combined with the potential increase in

flexibility that could be achieved, has led to suggestions that the 6 inch rule be reviewed.

Earth Tech (2007) undertook a detailed literature review of the 6 inch rule, complemented by

field and laboratory analysis. This review found bank slumping was not the primary driver of

erosion along this reach and that benefits could be achieved without significant risks of

negative outcomes (such as increased risk of erosion) by increasing the maximum allowable

rate of fall in specific circumstances. Through the analysis undertaken, and discussions with

River Murray Water staff (now the River Murray Division within the Authority), Earth Tech

(2007) proposed a more flexible 6-inch rule as follows:

1) June to December inclusive, no change, the maximum rate of fall will remain restricted to

150 mm/day (6 inches) at Doctors Point2 and 200 mm/day (8 inches) at Heywoods

3

2) January to May inclusive, the maximum daily rate of fall will be increased to 225 mm/day

(9 inches) at Doctors Point and Heywoods, however the average daily rate of fall over four

days will be retained at 150 mm/day (6 inches) at Doctors Point and 200 mm/day (8

inches) at Heywoods

3) When flows at Doctors Point are less than 12,000 ML/day, the maximum rate of fall will

remain restricted to 150 mm/day (6 inches) at Doctors Point and 200 mm/day (8 inches) at

Heywoods at all times.

Modelling of this option is based on adoption of the adjusted rule proposed by Earth Tech.

Modelling outcomes

Increasing the maximum rate of fall during the unseasonal flooding period would enable river

operators to respond more rapidly to decreased demand. This would be expected to reduce

unseasonal flooding of the Barmah-Millewa Forest by a small amount during smaller rainfall

runoff events by allowing releases to be reduced more quickly initially.

This was confirmed by modelling results (see Section 6) which indicated that this option

would lead to less than a 1% reduction in the number of years each side of the Barmah-

Millewa Forest is wet unseasonally.

Whilst it has been suggested that this option would be effective at reducing unseasonal

flooding, the effectiveness of this option is limited by the requirement to retain an average

daily rate of fall over four days of 150 mm/day (6 inches) at Doctors Point. Figure 3-2 and

Figure 3-3 show examples of the revised 6 inch rule in operation.

2 Doctors Point is the site of the flow gauging station on the River Murray approximately 17 km

downstream of Lake Hume, just downstream of the Kiewa River confluence. 3 Heywoods is the site of the flow gauging station on the River Murray approximately 1.2 km

downstream of Lake Hume.



Figure 3-2. Comparison of River Murray flow at Doctor‟s Point in March and April

2006 under Option 1 (do nothing) and Option 2.

Figure 3-3. Comparison of River Murray flow at Doctor‟s Point in April and May 1999

under Option 1 (do nothing) and Option 2

0

5000

10000

15000

20000

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30000D

oct

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Do Nothing

6 Inch Rule

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cto

rs P

oin

t Fl

ow

(M

L/d

ay)

Date

Do Nothing

6 Inch Rule



The modelling results indicate that this option would not impact on the incidence or magnitude

of shortfalls or the delivery of environmental flows (indicated by the incidence of beneficial

flooding of TLM icon sites). Additionally, this option would not be expected to impact on

constraints on water trade, as it does not impact on the volume of water that can be delivered to

below the Barmah Choke during the irrigation season.


Reducing the occurrence of unseasonal flooding would be expected to improve the health of

the Barmah-Millewa Forest. Reducing the occurrence of unseasonal flooding would also be

expected to improve opportunities for summer forest tourism activities by reducing the risk of

key recreational sites being inundated. It may also improve summer access through the forest

for tourism, management and emergency response by reducing the risk of key access paths

being inundated. This may improve the recreational value of, and access to, the Barmah-

Millewa Forest.

The 6-inch rule is currently in place to minimise the risk of bank slumping along the river

between Lake Hume and Lake Mulwala. Earth Tech (2007) found that bank slumping was not

the primary driver of erosion along this reach and to increase the operational flexibility they

proposed changes to the 6-inch rule. However, there may still be a risk that altering the 6-inch

rule would lead to an increased risk of erosion in the main stem of the Murray due to bank

slumping (Earth Tech, 2007). This risk would need to be carefully monitored if this option is

implemented.

Additionally, downstream of Hume Reservoir there are a number of anabranch systems which

interact with the main stem of the River Murray. Earth Tech (2007) recognised that increased

rates of fall may be amplified in the anabranch systems and may change the frequency of

cease- and commence-to-flow conditions to the anabranches. One anabranch of particular

concern is Ryan Creek, which is separated from the River Murray by a weir (Ryan Creek

Weir) with a commence-to-flow threshold of approximately 12,000 ML/day.

To ensure the frequency of cease- and commence-to-flow conditions for Ryan Creek were not

affected by the changes to the 6 inch rule, the increased rate of fall would not apply when flow

was below 12,000 ML/day. Due to a lack of data, the potential amplification of rates of rise in

the anabranch systems was not assessed. The nature and magnitude of the potential

amplification of rates of fall in the anabranch systems, and any measure required to mitigate

potential impacts, would need to be further investigated.



Option 2: alter the 6-inch rule to increase operational flexibility

Description

The 6-inch rule, adopted to minimise bank slumping, is the most conservative rate of

fall rule applied in the Murray-Darling Basin and limits the ability of operators to

respond to rapidly changing conditions.

This option considers the adoption of the following adjustment to the 6-inch rule, as

proposed by Earth Tech (2007) following a detailed review:

◦ June to December inclusive, no change, the maximum rate of fall will remain

restricted to 150 mm/day (6 inches) at Doctors Point and 200 mm/day (8 inches)

at Heywoods.

◦ January to May inclusive, the maximum daily rate of fall will be increased to

225 mm/day (9 inches) at Doctors Point and Heywoods however the average

daily rate over four days will be retained at 150 mm/day (6 inches) at Doctors

Point and 200 mm/day (8 inches) at Heywoods.

◦ when flows at Doctors Point are less than 12,000 ML/day, the maximum rate of

fall will remain restricted to 150 mm/day (6 inches) at Doctors Point and

200 mm/day (8 inches) at Heywoods at all times.

Modelling outcomes

less than a 1% reduction in the number of years each side of the Barmah-Millewa

Forest is wet unseasonally

no impact on shortfalls, the delivery of environmental water or constraints on water

trade


opportunity to improve the health, recreational value of, and access to, the Barmah-

Millewa Forest

opportunity to conserve water resource and increase operational flexibility.

risk of increasing erosion due to bank slumping along the river between Lake Hume

and Lake Mulwala (EarthTech, 2007) under certain circumstances.

risk of increasing rates of fall in anabranch systems including Ryan Creek in certain

flow ranges



3.3. Option 3a: policy options to manage within the capacity of the Barmah Choke- Lake Victoria Transfers

Option description

Lake Victoria may be used to supplement Murray River flows to supply South Australia‟s

requirements. The Lake Victoria Operating Strategy (Murray-Darling Basin Ministerial

Council, 2002) provides rules for the filling and drawing down of Lake Victoria as follows:

from 1 June, Lake Victoria is filled from River Murray unregulated flows (aim to fill as

late as possible)

from February to May, Lake Victoria is drawn down to supply South Australia based on a

target drawdown curve, supplemented by River Murray flows as required (these rules can

be relaxed slightly when upstream resources are low).

These rules mean that in years when volumes in Lake Victoria are low (and South Australian

entitlement flow is high), releases may be needed from upper system storages (Lake Hume) to

meet demands during the peak of the irrigation season. This can result in capacity constraints

in the Barmah Choke leading to shortfalls. The issues are also compounded by the travel time

between upper storages and Lake Victoria. Figure 3-4 shows the Lake Hume to Lake Victoria

transfer route on a schematic diagram of the River Murray System.

Figure 3-4: Schematic diagram of the River Murray System showing the Lake Hume to Lake Victoria transfer route.

This option considers modifications to the rules governing transfers from Lake Hume to Lake

Victoria. These rules would result in the transfer of water to Lake Victoria earlier in the

season, increasing available resources in Lake Victoria and allowing a lower transfer rate

during the peak irrigation season. Whilst this has occurred on occasion in the past, this option

would consider transferring water to Lake Victoria earlier in the season.

Lake Victoria Transfers

Tocumwal

Mulwala Canal


BARMAH CHOKE



Wakool River

Murray River


Forests

NSW-VIC-SA Border


Campaspe River


Goulburn River

Broken Creek

Lake Eildon

Torrumbarry Weir

Goulburn Weir

Lake Victoria


Dartmouth Reservoir

Mitta Mitta River

Murrumbidgee River


Darling River


Lake Boga

Snowy Mountains


Loddon River

Finley Escape

Picnic Point

Kiewa River

Ovens River


Edward Escape



To model the transfer of water from Lake Hume to Lake Victoria earlier in the season, this

option would increase the monthly minimum target storage for Lake Victoria outside of the

unseasonal flooding period (to encourage greater transfers before the start of the unseasonal

flooding period) and would reduce the volume of channel capacity downstream of Yarrawonga

that may be used for transfers over the unseasonal flooding period as summarised in Table 3-2.

Note that while this is just one possible combination of new targets, this option was assessed to

give an indication of the potential of this option, rather than identify the optimal option

arrangements. If the results indicate this option may be suitable for implementation, further

investigation to determine the optimal arrangements would be required.

Table 3-2: Changes to minimum storage target and channel capacity used for transfers used to model the transfer of water from Lake Hume to Lake Victoria earlier in the season for Option 3a.

Month

Lake Victoria monthly minimum storage target (GL)

Monthly channel capacity downstream of Yarrawonga used for

transfers (GL)

Base Case Option 3a Base Case Option 3a

June 140 164 328.6 328.6

July 140 164 425 425

August 180 250 425 425

September 200 300 425 425

October 200 400 501 501

November 200 400 661 661

December 200 300 661 661

January 200 200 425 425

February 200 200 328.6 186

March 200 200 296.8 168

April 180 180 328.6 186

May 250 165 318 160

Modelling outcomes

Transferring water to Lake Victoria earlier in the season would provide increased flexibility to

manage lower system demands by increasing the volume of water in storage in the lower

Murray system, reducing call on upper system storages. This would be expected to lead to a

reduction in the incidence and magnitude of lower system storage (type II) shortfall events.

Modelled results (see Section 6) found that this option would lead to a 21% reduction in the

number of years with shortfall events, in particular the number of years with lower system

storage (type II) shortfall events has halved (from seven years under the base case to three

years).



The modelling results also found that this option would lead to a 7% reduction in the number

of years each side of the Barmah-Millewa Forest is wet unseasonally. Reducing pressure on

the Barmah Choke to deliver Lake Victoria transfers over the unseasonal flooding period

means that the Barmah Choke may be operated at a lower level in some years. This provides

additional buffer capacity to absorb rainfall rejections within the river channel, leading to a

reduction in unseasonal flooding.

The modelling results indicate that this option would not impact on the delivery of

environmental water (indicated by the incidence of beneficial flooding of TLM icon sites).

This option may reduce the time that the Barmah Choke is at capacity during the irrigation

season, however the magnitude of this impact is not expected to be sufficient to impact

(reduce) constraints on water trade.


This option would be expected to lead to a reduction in the incidence and magnitude of lower

system storage (type II) shortfall events which may have a number of positive social and

economic impacts.

Evaporation rates from Lake Victoria are significantly higher than evaporation rates from the

upper system storages. Storing additional water in Lake Victoria rather than in upper system

storages may increase the volume of total evaporation. This, together with the increased risk of

spill from Lake Victoria may result in a very minor reduction in available water resources (the

modelling results indicate no change in water availability (allocations)).

The existing operating rules for Lake Victoria (Murray-Darling Basin Ministerial Council,

2002) were developed to meet the needs of foreshore vegetation and sites of significance for

indigenous cultural heritage which are sensitive to the influences of water levels. The impact

of any modification to the operating strategy on foreshore vegetation and significant

indigenous cultural heritage sites would need to be considered, however, as future operations

would still need to comply with the Lake Victoria Operating Strategy and meet the objectives

and conditions of the (section 90) consent to operate, the risk of significant impact would be

expected to be low.



Option 3a: policy options to manage within the capacity of the Barmah Choke- Lake Victoria transfers

Description

this option considers increasing the monthly minimum target storage for Lake Victoria

outside of the unseasonal flooding period, and reducing the volume of channel

capacity downstream of Yarrawonga used for Lake Hume to Lake Victoria transfers

during the unseasonal flooding period to transfer more water from Lake Hume to Lake

Victoria earlier in the season

Modelling outcomes

21% reduction in the number of years with shortfall events, with a particular reduction

in the number of years with lower system storage (type II) shortfall events

7% reduction in the number of years each side of the Barmah-Millewa Forest is wet

unseasonally

no impact on the delivery of environmental flows or constraints on water trade


opportunity to reduce the incidence and magnitude of lower system storage (type II)

shortfall events leading to social and economic benefit

risk of reduced resource availability due to increased evaporation and increased risk of

spills from Lake Victoria due to less re-regulation capacity

low risk of potential negative impact on foreshore vegetation and sites of significance

for Indigenous cultural heritage (operations would continue to comply with the Lake

Victoria Operating Strategy and section 90 consent)



3.4. Option 3b: policy options to manage within the capacity of the Barmah Choke- inter-valley trade

Option description

In recent years there have been significant volumes of entitlement (permanent) and allocation

(temporary) trade out of both the Goulburn and Murrumbidgee systems (NWC, 2010). This

has created inter-valley trade credits on both systems which could be used to meet peak

irrigation demands on the River Murray System. The available water from the Goulburn

system is approximately 110 GL per year and while not modelled, since 1997 there has been

up to 70 GL per year from the Murrumbidgee system. Improved use of inter-valley trade has

the potential to decrease problems caused by capacity constraints at the Barmah Choke.

Figure 3-5 shows the main sources of inter-valley trade credits to the River Murray System on

a schematic diagram.

Figure 3-5: Schematic diagram of the River Murray System showing the main

sources of inter-valley trade credits to the River Murray System.

This option considers modifications to the rules for the order and release of inter-valley trade

credits, with the revised release rules developed specifically to manage shortfalls.

Within MSM-Bigmod, supply to the River Murray System from the inter-valley trade accounts

is based on fixed calling rules and patterns. To model this option, the fixed calling patterns for

release of water from the Goulburn inter-valley trade account were adjusted such that more

water could be released during the months shown to have the greatest incidence of shortfalls

under the base case (Option 1). Note that within MSM-Bigmod there is no water in the

Murrumbidgee inter-valley trade account, so this account was not investigated.

Adjust Use of IVT(Goulburn and Murrumbidgee Rivers)

Tocumwal

Mulwala Canal


BARMAH CHOKE



Wakool River

Murray River


Forests

NSW-VIC-SA Border


Campaspe River


Goulburn River

Broken Creek

Lake Eildon

Torrumbarry Weir

Goulburn Weir

Lake Victoria


Dartmouth Reservoir

Mitta Mitta River

Murrumbidgee River


Darling River


Lake Boga

Snowy Mountains


Loddon River

Finley Escape

Picnic Point

Kiewa River

Ovens River


Edward

Escape



An example of how the inter-valley trade works is outlined in Figure 3-6. This shows that for

an example 100 GL account using the IVT release pattern from the Option 1- do nothing

model. In November up to 5 GL can be used for trade out of the Goulburn system. In

December any entitlement from November which is not used plus 21.3 GL can be traded out of

the Goulburn system. This process continues all the way through to March where 44.4 GL plus

any available entitlement from November through to March can be traded out of the Goulburn

system.

Figure 3-6: Example showing the operation of the Goulburn System IVT account under Option 1- do nothing.

The adjustment to the fixed calling pattern for this option is shown in Table 3-3. Note that

while this is just one possible set of new release rules, this option is assessed to give an

indication of the potential, rather than identify the optimal option arrangements. If the results

indicate this option may be suitable for implementation, further investigation would be

required to determine preferred release rules.

5 5 5 5 5

21.3 21.3 21.3 21.3

9.4 9.4 9.4

19.9 19.9

44.4

0

10

20

30

40

50

60

70

80

90

100

November December January February March

Tran

sfe

r En

titl

em

en

t (G

L)

Month

Minimum March Entitlement

Minimum February Entitlement

Minimum January Entitlement

Minimum December Entitlement

Minimum November Entitlement



Table 3-3: Changes to the maximum fraction of the remaining End of Valley Account (EVA) balance that can be used this month (Goulburn system) for Option 3b.

Month

Maximum fraction of the remaining EVA balance that can be used this month

Base Case Option 3b

January 0.357 0.651

February 0.556 0.957

March 1.000 1.000

April 0.000 0.000

May 0.000 0.000

June 0.000 0.000

July 0.000 0.000

August 0.000 0.000

September 0.000 0.000

October 0.000 0.000

November 0.050 0.000

December 0.263 0.199

Modelling outcomes

Modification of the rules for ordering and releasing inter-valley trade credits would increase

flexibility to manage peak demands by allowing inter-valley transfer flows to be used to help

meet demands downstream of the Barmah Choke. This would be expected to reduce the

incidence and magnitude of shortfall events.

The use of this option to manage peak demand (type I) shortfalls (typically large volume, rapid

onset shortfalls) may be limited by the long travel times between the release points (e.g. Lake

Eildon for the Goulburn River) and the River Murray. However this option would be expected

to provide significant flexibility for managing lower system storage (type II) shortfalls (which

are generally longer in duration).

The use of this option may also be limited by the availability of inter-valley trade water during

times of shortfalls. Historical trade trends indicate that inter-valley trade is highest (number of

trades) when allocations are low and the capacity of the Barmah Choke is not acting as a

constraint.

Modelling results (see Section 6) found that this option would lead to an 11% reduction in the

number of years with shortfall events, in particular the option would lead to a 30% reduction in

the number of years with lower system storage (type II) shortfall events (from seven years

under the base case to five years).



Modelling results also found that this option would lead to a 3% reduction in the number of

years each side of the Barmah-Millewa Forest is wet unseasonally. Concentrating the delivery

of inter-valley trade transfers during the peak demand months means that the Barmah Choke

may be operated at a lower level in some years. This provides increased capacity to contain the

additional flows caused by rainfall rejections within the river channel, leading to a reduction in

unseasonal flooding.

The modelling results indicate that this option would not impact on the delivery of

environmental water (indicated by the incidence of beneficial flooding of TLM icon sites).

This option would affect the timing of tributary inflows to the River Murray System (from the

Goulburn and Murrumbidgee Rivers) however the total volume of inflows over the irrigation

season would not change (this may slightly change the total volume of water which must be

transferred from upstream to downstream of the Barmah Choke to meet irrigation demands due

to changes in the timing of other tributary inflows). As the changes would be expected to be

minor, this option is not expected to impact on constraints on water trade.



system storage (type II) shortfall events, which may have positive social and economic

impacts.

However, concerns exist about the need to supply large volumes of inter-valley trade credits

through the lower reaches of the Goulburn and Murrumbidgee rivers. Water to supply trade

credits would most likely be released during the summer and autumn peak of the irrigation

season. This may affect the flow regime of these rivers. There may also be losses associated

with delivering inter-valley trade credits at high flow rates through these systems (for example,

loses to the Lowbidgee wetlands along the Murrumbidgee River).

The volume of water available would also depend on allocations in the Murrumbidgee and

Goulburn River systems, and the volume of trade that has occurred (variable). As noted above,

historical trade trends indicate that inter-valley trade is highest (number of trades) when

allocations are low and the capacity of the Barmah Choke is not acting as a constraint to the

downstream transfer of water. This may limit the ability of this option to manage shortfalls.

Implementing this option would also require a high level of cooperation between the MDBA

and State water agencies.



Option 3b: policy options to manage within the capacity of the Barmah Choke- inter-valley trade

Description

this option considers modifications to the rules for the order and release of inter-valley

trade credits from the Goulburn System. The revised rules would be developed

specifically to manage shortfalls, concentrating the use of releases from inter-valley

trade accounts during periods most likely to experience shortfalls.

Modelling outcomes

11% reduction in the number of years with shortfall events, with a particular reduction

in the number of years with lower system storage (type II) shortfall events


unseasonally




shortfall events leading to social and economic benefits

available water will vary annually depending on allocations and the volume of trade,

risk that water will not be available when required

implementation will require the cooperation of State water agencies

risk of potential impacts on the flow regime of the rivers where the inter-valley trade

credits are generated.



3.5. Option 3c: policy options to manage within the capacity of the Barmah Choke- non-asset solutions

Assessing non-asset solutions is often a critical requirement of funding agencies when

assessing capital program bids. Should a business case be developed in the future for a capital

program for the Barmah Choke, it will need to consider non-asset solutions. Non-asset

solutions require important consideration as they can mean significant avoided costs,

especially where large capital investments are proposed.

This section provides an overview of potential non-asset solutions that could be used to

manage the impacts of capacity constraints in the Barmah Choke and recommends whether

they should be investigated further based on their potential to deliver an efficient and effective

solution.

The non-asset solutions assessed include:

tradable capacity shares

covenants or options on entitlements

use of environmental entitlements

incentive or congestion pricing measures.

It is important to note that the non-asset solutions considered (apart from environmental

entitlements) cannot reduce the incidence or magnitude of shortfalls and they are not expected

to have an impact on undesirable flooding of the Barmah-Millewa Forest. The primary purpose

is to provide a solution that enables river operators and the irrigation community to manage the

impact of shortfalls effectively (and efficiently). By reducing the impact of peak demand (type

I) and lower system storage (type II) shortfalls, these non-asset solutions can achieve a number

of positive social and economic impacts at low cost (noting some will have distributional

impacts which will require consideration).

The solutions considered (except for the use of environmental entitlements) may also

encourage improved irrigation efficiency and alternatives to using water in peak periods (e.g.

on-farm storages). A signal of the value of water during peak times may encourage investment

in local solutions such as on-farm storage.

Each of the solutions is discussed in more detail in Appendix A, however a summary of the

results is provided in Table 3-4. Note, these solutions are an investigation option only; no

hydrological modelling was undertaken and it remains a preliminary assessment only.



Table 3-4: Summary of assessment of non-asset solutions.

Solution Effectiveness Efficiency Comment

Tradable capacity shares

While this solution offers a neat way of managing the congestion, difficulties in establishing a well functioning market reduces the efficiency

Covenants or options on entitlements

This option is likely to be costly and without an appropriate legislative backing would not be effective.

Use of environmental entitlements

Has potential to be an efficient and effective way of reducing the impacts of shortfalls as well as reducing total shortfalls altogether.

Incentive or congestion pricing measures

Difficult to assess whether pricing would provide the necessary incentives to change behaviour. Therefore not considered effective.

It is recommended that further modelling is undertaken to better understand the impact of

environmental entitlements and their use to reduce the incidence of shortfalls. The key

requirement will be to understand the anticipated use of environmental water and use this

understanding in modelling. Development of appropriate rules is likely to require discussion

between the CEWH and the MDBA.



3.6. Option 4: increased operational flexibility in existing assets: Mildura Weir

Option description

Mildura Weir (Lock 11) is located on the River Murray at Mildura upstream of the Darling

River confluence. Mildura Weir raises water levels in the River Murray to provide a constant

water level for diversions to the Sunraysia irrigation district and private diverters and to

maintain navigation for recreational users. Figure 3-7 shows the location of Mildura Weir on a

schematic diagram of the River Murray System.

Figure 3-7: Schematic diagram of the River Murray System showing the location of Mildura Weir.

Mildura Weir currently operates to a full supply level of 34.4 m AHD. Current operating

practice is to maintain the weir at full supply level throughout the irrigation season with a

tolerance of ± 50 mm.

The primary aim of this option in relation to the Barmah Choke Study is the management of

shortfalls. This option requires Mildura Weir to be kept at full supply level through the

irrigation season and temporarily drawn down (and refilled at the earliest opportunity) to avoid

shortfalls by supplying demands when sufficient water cannot be supplied from upper system

storage (no change to the target operating level).

SMEC (2002) investigated the potential to lower the operating level of Mildura Weir for

specific periods of time during summer and autumn to dry out wetlands adjacent to the weir

pool; however appropriate maximum drawdown levels were not specified. Note that weir pool

lowering for this purpose would be expected to require longer periods of drawdown than is

proposed for this option to allow wetlands to drain and dry out. The normal maximum

Mildura Weir(Lock 11)

Tocumwal

Mulwala Canal


BARMAH CHOKE



Wakool River

Murray River


Forests

NSW-VIC-SA Border


Campaspe River


Goulburn River

Broken Creek

Lake Eildon

Torrumbarry Weir

Goulburn Weir

Lake Victoria


Dartmouth Reservoir

Mitta Mitta River

Murrumbidgee River


Darling River


Lake Boga

Snowy Mountains


Loddon River

Finley Escape

Picnic Point

Kiewa River

Ovens River


Edward

Escape



drawdown level of Mildura Weir is approximately 3.5 m (30.9 m AHD) and the weir is

routinely (every few years) drawn down to this level for maintenance.

This option considers two alternative sub-options for temporarily lowering the water level at

Mildura Weir (alternative lower levels):

Option 4a: minimum operating level lowered by 1.0 m to 33.4 m AHD, accessing 10 GL

of active storage over the „do nothing‟ option

Option 4b: minimum operating level lowered by 2.0 m to 32.4 m AHD, accessing 20 GL

of active storage over the „do nothing‟ option

Note that before implementing this option the MDBA would need to confirm that the degree of

flexibility proposed for this option can be achieved without significant structural modification

to the weir and lock. The 2010 upgrade to the weir to improve the ease and safety of operation

is believed to have provided the required degree of flexibility.

Modelling outcomes

Lowering the minimum operating level of Mildura Weir while maintaining the target storage at

full supply level would increase the mid-river storage capacity, which may be used to

supplement flow to meet demands when sufficient water cannot be supplied from upper system

storages. This would be expected to reduce the incidence and magnitude of shortfall events.

The use of this option to manage lower system storage (type II) shortfalls (generally long in

duration and of large volume) may be limited by the volume of drawdown water available.

However, this option is expected to provide flexibility for managing peak demand (type I)

shortfalls with the option providing a volume of water that can be drawn upon to mitigate a

shortfall event.

Modelling results (see Section 6) indicate that this option would lead to a reduction in the

number of years with shortfall events of between 43% and 54% (for a 1 m and 2 m lowering of

the minimum operating level respectively).

Due to the spreadsheet based assessment approach adopted for this option the impact on

unseasonal flooding of the Barmah-Millewa Forest and other key project issues has not been

simulated. However, as this option only changes operations through the Barmah Choke by

requiring additional flows to be delivered following the end of the drawdown event to re-fill

Mildura Weir, this option is not expected to significantly impact on unseasonal flooding of the

Barmah-Millewa Forest or the delivery of environmental flows. This is based on an assessment

of the coincidence of shortfall events ending with an unseasonal flooding event. This option

does not impact on the total volume of water which must be transferred from upstream to

downstream of the Barmah Choke to meet irrigation demands (Mildura Weir would need to be



re-filled after each drawdown event). As such, this option is not expected to impact on

constraints on water trade.


This option would be expected to lead to a reduction in the incidence and magnitude of peak

demand (type I) shortfall events, which may have a number of positive social and economic

impacts.

Weir pool lowering to improve the health of surrounding wetlands and forest areas (red gums)

would be expected to require longer periods of drawdown than is proposed for this option to

allow wetlands to drain and dry out. However, some complementary benefits may still be

possible if lowering the water level in Mildura Weir pool during summer or autumn, even for

short periods of time, has the potential to improve the health of the surrounding wetlands and

forest areas (red gums) by moving towards a more natural flow regime (reduced summer

inundation) (SKM, 2005).

Lowering the minimum operating level of Mildura Weir may have some negative impacts on:

recreational use of Mildura Weir; reducing the operating level will reduce the area

available for boating and houseboating (including mooring and boat ramps). Lowering the

operating level may also increase safety risks associated with activities such as boating,

houseboating and water skiing with an increased risk of incidents with submerged debris

(logs and snags). This may affect tourism to the area, with a number of social and

economic impacts.

pumped diversions from the weir pool; the weir pool raises water levels to enable pumped

diversions for private diverters. Depending on the extent of the drawdown some pumps

may need to be modified (including extensions to suction lines) or replaced.

The presence of the weir lowers salinity in the weir pool and river downstream of Mildura.

During weir lowering exercises for routine maintenance, salinity levels in the weir pool rise,

requiring careful monitoring and management, including releases of dilution flows from

upstream. The extent to which this issue limits the suitability of this option is not clear and

should be investigated if the option is progressed. As the weir would only be drawn down for

short periods of time, the salinity impacts are not expected to impact on the option‟s viability

as the current arrangements used when the weir is drawn down for maintenance could be used.



Option 4: increased operational flexibility in existing assets – Mildura Weir

Description

Mildura Weir would be operated at the target storage (full supply level of 34.4 m AHD)

throughout the irrigation season and drawn down to minimum operating level as

follows to supply demands and avoid shortfalls:

◦ Option 4a: minimum operating level lowered by 1.0 m to 33.4 m AHD (10 GL of

active storage)

◦ Option 4b: minimum operating level lowered by 2.0 m to 32.4 m AHD (20 GL of

active storage)

Modelling outcomes

43% to 54% reduction in the number of years with shortfall events (Option 4a and

Option 4b respectively)

no impact on unseasonal flooding of the Barmah-Millewa Forest, the delivery of

environmental flows or constraints on water trade


opportunity to reduce the incidence and magnitude of peak demand (type I) shortfalls

leading to social and economic benefits

◦ opportunity to improve the health of wetland and forest areas (red gum)

surrounding Mildura Weir

risk of negative impacts on weir and river salinity

risk of negative impacts on recreational use



3.7. Option 5: lower operating level in Lake Mulwala

Option description

Lake Mulwala operating rules state the minimum operating level to be 124.6 m AHD and the

full supply level to be 124.9 m AHD; however it is noted that the level can be surcharged to

125.15 m AHD for short periods if necessary (for example, to reduce unseasonal flooding)

(SKM, 2009). During the irrigation season, the normal operating range of Lake Mulwala is

124.6 m AHD to 124.9 m AHD with a target level of 124.7 m AHD. These levels are required

to maintain gravity supplies to the Yarrawonga Main Channel and Mulwala Canal. Note that

this operating regime is simulated in the model using a target level of 124.6 m AHD.

Lowering the minimum (and normal) operating level of Lake Mulwala over the unseasonal

flooding period would provide air space in the lake which can be used to capture and re-

regulate rainfall rejections upstream of the Barmah Choke, reducing unseasonal flooding of the

Barmah-Millewa Forest. Figure 3-8 shows the location of Lake Mulwala on a schematic

diagram of the River Murray System.


Lake Mulwala.

The potential to lower the minimum and normal operating level has been investigated in

previous studies including SKM (2006c) and SMEC (2002). SMEC (2002) investigated the

potential for lowering the minimum and normal operating level by 0.5 m to 124.1 m AHD.

SKM (2006c) investigated a range of potential lowering options between 0.1 m and 1.0 m,

finding that lowering options between 0.1 m and 0.5 m were similarly cost effective and

similarly ranked in a multi-criteria analysis.

This option considers two alternative sub-options (alternative lower levels):

Lake Mulwala

Tocumwal

Mulwala Canal


BARMAH CHOKE



Wakool River

Murray River


Forests

NSW-VIC-SA Border


Campaspe River


Goulburn River

Broken Creek

Lake Eildon

Torrumbarry Weir

Goulburn Weir

Lake Victoria


Dartmouth Reservoir

Mitta Mitta River

Murrumbidgee River


Darling River


Lake Boga

Snowy Mountains


Loddon River

Finley Escape

Picnic Point

Kiewa River

Ovens River


Edward Escape



Option 5a: target level lowered over the unseasonal flooding period by 0.1 m to 124.5 m

AHD, creating 4,380 ML of airspace over the „do nothing‟ option

Option 5b: target level lowered over the unseasonal flooding period by 0.5 m to 124.1 m

AHD, creating 21,290 ML of airspace over the „do nothing‟ option

Modelling outcomes

Lowering the minimum (and normal) operating level of Lake Mulwala over the unseasonal

flooding period (January to April) would increase available air space to capture and re-regulate

rainfall rejections and unregulated flows upstream of the Barmah Choke. This would be

expected to reduce unseasonal flooding of the Barmah-Millewa Forest. Lowering the

minimum (and normal) operating level would also be expected to lead to an increase in water

resources available due to the capture and re-regulation of unseasonal flows.


number of years each side of the Barmah-Millewa Forest is wet unseasonally of between 19%

and 54% (for a 0.1 m and 0.5 m lowering of the normal operating level over the unseasonal

flooding period, respectively).

The modelling results indicate that this option would not impact on the incidence or magnitude

of shortfalls or the delivery of environmental flows (indicated by the incidence of beneficial

flooding of TLM icon sites). Additionally, this option would not be expected to impact on

constraints on water trade, as it does not impact on the volume of water that can be delivered to

below the Barmah Choke during the irrigation season.



the Barmah-Millewa Forest.

Reducing the occurrence of unseasonal flooding of the forest would also be expected to

improve opportunities for summer forest tourism activities by reducing the risk of key

recreational sites being inundated. It may also improve summer access through the forest for

tourism, management and emergency response by reducing the risk of key access paths being

inundated. This may improve the recreational value of, and access to, the Barmah-Millewa

Forest.

Lowering the minimum (and normal) operating level of Lake Mulwala may have some

negative impacts on:

recreational use of Lake Mulwala; reducing the operating level will reduce the area

available for boating (recreational navigation) and potentially increase safety risks with

increased risks of incidents with submerged debris (logs and snags) (SKM, 2006c).



diversions to Yarrawonga Main Channel; a target level of 124.75 m AHD is required to

maintain full capacity supplies to Yarrawonga Main Channel. (3,100 ML/day). Reducing

the operating level would reduce the ability to run the Yarrawonga Main Channel at

capacity. To ensure supplies are not compromised, the 8 Mile Measuring Weir on the

Yarrawonga Main Channel may need to be removed and additional modifications may be

required on the main channel depending on the extent of the lowering (SMEC, 2002).

Diversions to Mulwala Canal are not expected to be affected.

operation of the fishway; reducing the operating level will reduce the operating head

available for the existing fishway (required to generate appropriate flow conditions to

attract fish). The exit race of the fishway may need to be modified to maintain its

efficiency (SMEC, 2002).

hydro-power station operation; reducing the operating level will reduce the operating head

available for the hydro-power station. The log boom at the entrance to the hydro-power

generator may need to be modified (SMEC, 2002).

The potential impact on recreational use of Lake Mulwala, is likely to raise community

concern. The MDBA remains committed to the “Lake Mulwala Land and On-water

Management Plan”. The plan, originally developed and released in 2004 by Goulburn-Murray

Water and the former MDBC, states that:

“In the specific case of looking for options to better manage rain rejections at Lake

Mulwala in order to achieve healthier outcomes in the Barmah-Millewa Forest, there

will need to be extensive economic and social impact studies, specifically relating to

Lake Mulwala. These studies have not been commenced, nor even scoped.” (G-MW,

2004)

This statement still holds. In 2008, an addendum to the plan was released by Goulburn-Murray

Water and the MDBA which, without changing the original plan, included specific actions and

strategies relevant to the current (dry conditions) operating environment (G-MW, 2008).

The addendum stated that in relation to options to better manage rainfall rejections (all options,

including a lower operating level in Lake Mulwala) the MDBA would:

complete any necessary environmental, social and economic studies

consider a wide range of engineering and operational responses

present the findings of these studies to the community as the basis for meaningful

discussion

hold discussions with the community

report the findings of those discussions to the Murray-Darling Basin Ministerial Council,

which will determine what, if any, changes to current operating rules will be implemented,

including any works to facilitate such changes.



Option 5: lower operating level in Lake Mulwala

Description

Lake Mulwala would be operated at a lower minimum (and normal) level over the

unseasonal flooding period to provide airspace in the lake, which could be used to

capture and re-regulate rainfall rejections upstream of the Barmah Choke as follows:

◦ Option 5a: target level lowered over the unseasonal flooding period by 0.1 m to

124.5 m AHD (4,380 GL of air space)

◦ Option 5b: target level lowered over the unseasonal flooding period by 0.5 m to

124.1 m AHD (21,290 ML of airspace)

Modelling outcomes

19% to 54% reduction in the number of years each side of the Barmah-Millewa Forest

is wet unseasonally (Option 5a and Option 5b, respectively)

no impact on shortfalls, the delivery of environmental flows or constraints on water

trade



Millewa Forest

opportunity to conserve water resources (capture and re-regulate rainfall rejections)

risk of potential negative impacts on recreational use of Lake Mulwala

risk to operation of fishway, hydro-power station and 8 Mile Measuring Weir



3.8. Option 6: enlarged storage capacity in Euston Weir

Option description

Euston Weir (Lock 15) is located on the River Murray downstream of the Murrumbidgee

River confluence. Euston Weir raises water levels in the River Murray to enable water to be

pumped from the weir pool to supply the Robinvale irrigation area (Victoria), private diverters

(predominantly NSW) and urban supplies (Robinvale and Euston) and to maintain navigation

for recreational users. Figure 3-9 shows the location of Euston Weir on a schematic diagram of

the River Murray System.


Euston Weir.

Euston Weir is currently operated to a full supply level of 47.6 m AHD. Since the mid-1990s

operational practice has allowed a maximum drawdown of 0.3 m (approximately 4 GL) over

the irrigation season to 47.3 m AHD (SKM, 2006b). Works have recently (2010) been

undertaken at Euston Weir to improve the structural integrity of the weir, upgrade the fishway

and protect against erosion. These works may allow the active storage capacity of Euston Weir

to be enlarged by either raising the maximum operating level, lowering the minimum operating

level or both.

The operating strategy of the enlarged Euston Weir would dictate the outcomes of the option in

relation to the project objectives:

operating Euston Weir lower (or raising the weir without raising the target storage) would

generate additional air space in the weir to capture unregulated flows. This option may

increase the efficiency of River Murray System operations (depending on whether the

unregulated flows could have been re-regulated in Lake Victoria).

Euston Weir

Tocumwal

Mulwala Canal


BARMAH CHOKE



Wakool River

Murray River


Forests

NSW-VIC-SA Border


Campaspe River


Goulburn River

Broken Creek

Lake Eildon

Torrumbarry Weir

Goulburn Weir

Lake Victoria


Dartmouth Reservoir

Mitta Mitta River

Murrumbidgee River


Darling River


Lake Boga

Snowy Mountains


Loddon River

Finley Escape

Picnic Point

Kiewa River

Ovens River


Edward Escape



operating Euston Weir at full supply level and either increasing the weir level (and target

level) or lowering the minimum operating level would increase the volume of water in

storage mid-river which can be called on to meet peak irrigation demands. This operating

strategy may help reduce peak demand shortfalls.

The primary aim of this option in relation to the Barmah Choke Study is the management of

shortfalls. This requires Euston Weir to be kept at full supply level (or an increased level)

throughout the irrigation season and drawn down to prevent shortfalls when sufficient water

cannot be supplied from upper system storages.

SKM (2006b) investigated potential for lowering the minimum operating level by 1.5 m to

46.1 m AHD (providing a drawdown volume of 17,500 ML), finding it effective for reducing

the occurrence of shortfalls. SKM (2005) investigated a range of potential lowering options

between 0.5 m and 2.0 m finding that drawdowns of up to 1.0 m could be achieved without

requiring significant modifications to the major pump stations (Robinvale irrigation pump and

Euston town pump). Lowering the minimum operating level was also considered in SMEC

(2002).

This option considers three alternative sub-options:

Option 6a: maximum (and target) operating level raised by 0.5 m to 48.1 m AHD, creating

7 GL of active storage over the „do nothing‟ option

Option 6b: minimum operating level lowered by 1.5 m to 46.1 m AHD, creating 14 GL of

active storage over the „do nothing‟ option

Option 6c: maximum (and target) operating level raised by 0.5 m to 48.1 m AHD and

minimum operating level lowered by 1.5 m to 46.1 m AHD, creating 21 GL of active

storage.

Note, due to concerns and recent experience regarding the difficulty of re-filling Lake Benanee

following extensive drawdown, the volume of active storage considered for this option is

based on the volume of water in the weir pool excluding Lake Benanee.

Modelling outcomes

Lowering the minimum operating level of Euston Weir, while maintaining the target storage at

full supply level (or increasing the maximum and target levels), would increase the volume of

water in storage mid-river. The increased volume could be used to supply peak demands when

sufficient water cannot be supplied from upper system storages. This would be expected to

reduce the incidence and magnitude of shortfall events.


duration and of large volume) may be limited by the volume of active storage accessible.

However, this option would be expected to provide flexibility for managing peak demand



(type I) shortfalls with the option providing a volume of water which can be rapidly drawn

upon to mitigate a shortfall event.


number of years with shortfall events of 32% for Option 6a, 50% for Option 6b and 54% for

Option 6c. The majority of the reduction in the number of years arises from reductions in the

number of years with peak demand (type I) shortfall events, with minimal impact on lower

system storage (type II) shortfall event.

Due to the spreadsheet based assessment approach adopted for this option the impact on




Euston Weir, this option is not expected to significantly impact on unseasonal flooding of the




downstream of the Barmah Choke to meet irrigation demands (Euston Weir would need to be

re-filled after each drawdown event). As such, this option is not expected to impact on

constraints on water trade.




impacts.

Lowering the water level in Euston Weir pool during summer or autumn, even for short

periods of time, also has the potential to improve the health of the surrounding wetlands and

forest areas (red gums) by moving towards a more natural flow regime (reduced summer

inundation) (SKM, 2005). However, operating Euston Weir at a higher level (i.e. raising the

weir) during summer and autumn as is proposed for Option 6a and 6c is recognised as having a

number of significant negative environmental impacts on the surrounding wetlands and forest

areas (red gums) (RMC, 1980 and SMEC, 2002).

Lowering the minimum operating level of Euston Weir may also have some negative impacts

on:

recreational use of Euston Weir; reducing the operating level will reduce the area

available for boating and houseboating (including mooring) and impact on navigation with

the „cut‟ (a short channel crossing a large meander in the River Murray near Robinvale)

potentially ceasing to flow at lower drawdown levels. Lowering the operating level may

also increase safety risks associated with activities such as boating, houseboating and



water skiing with an increased risk of incidents with submerged debris (logs and snags)

(SKM, 2005). In particular, lowering the operating level during the annual Robinvale boat

race (Victorian Labour Day weekend in March) would have significant social and

economic impacts on the townships near Euston Weir (SKM, 2005).

pumped diversions from the weir pool; the weir pool raises water levels to enable pumped

diversions for private diverters, the Robinvale irrigation area and urban supplies.

Depending on the extent of the drawdown, some pumps may need to be modified

(including extensions to suction lines) or replaced (SMEC, 2002 and SKM 2005).

operation of the fishway; reducing the operating level would reduce the operating head

available for the existing fishway (required to generate appropriate flow conditions to

attract fish). If lower operating levels are maintained for extended periods of time (i.e.

several weeks or months) the exit race of the fishway may need to be modified to maintain

its effectiveness (SMEC, 2002).



Option 6: enlarge storage capacity in Euston Weir

Description

Euston Weir would be kept at full supply level (or an increased level) throughout the

irrigation season and rapidly drawn down to prevent shortfalls when sufficient water

cannot be supplied from upper system storages as follows:

◦ Option 6a: maximum (and target) operating level raised by 0.5 m to 48.1 m AHD

(7 GL of active storage)

◦ Option 6b: minimum operating level lowered by 1.5 m to 46.1 m AHD (14 GL of

active storage)

◦ Option 6c: maximum (and target) operating level raised by 0.5 m to 48.1 m AHD

and minimum operating level lowered by 1.5 m to 46.1 m AHD (21 GL of active

storage)

Modelling outcomes

reduction in the number of years with shortfall events of 32% for Option 6a, 50% for

Option 6b and 54% for Option 6c, with the majority of the reduction due to a reduction

in the number of years with peak demand (type I) shortfall events






opportunity to improve the health of wetland and forest areas (red gums) surrounding

Euston Weir) for sub-options which involve lowering (Options 6b and 6c), risk of

negative impacts for sub-options which involve raising over summer and autumn

(Options 6a and 6c)

risk of potential negative impacts on recreational use of Euston Weir



3.9. Option 7: storage at “The Drop” on Mulwala Canal

Option description

“The Drop” is an energy dissipation structure on Mulwala Canal, built to manage flow over a

sharp fall in land elevation. The Drop structure also enables diversions from Mulwala Canal to

Berrigan Canal which supplies the Berriquin irrigation area. Figure 3-10 shows the location of

The Drop on Mulwala Canal on a schematic diagram of the River Murray System.


The Drop on Mulwala Canal.

Constructing a storage at The Drop could allow rainfall rejection and other unregulated flows

to be diverted from the River Murray at Lake Mulwala upstream of the Barmah Choke. This

may reduce undesirable flooding of the Barmah-Millewa Forest.

The potential to develop a storage at The Drop was investigated by GHD (2007) who proposed

three alterative storage volumes (6 GL, 11 GL and 16 GL) with an inlet capacity of

9,000 ML/day and an outlet capacity of 3,000 ML/day. The aim of that study was to

investigate the use of the first 6 GL of the storage to capture rainfall rejections and the

remaining storage volume to provide additional operational flexibility within the Murray

Irrigation Limited (MIL) water delivery system4.

4 To capture rainfall rejections the storage would need to be kept empty most of the time, however to

provide operational flexibility within the MIL water delivery system the storage would need to be kept

full most of the time.

The primary aim of this option in relation to the Barmah Choke Study is the management of rainfall

rejections. This requires the proposed storage to be kept empty to provide air space for capturing rainfall

rejections.

The Drop(on Mulwala Canal)

Tocumwal

Mulwala Canal


BARMAH CHOKE



Wakool River

Murray River


Forests

NSW-VIC-SA Border


Campaspe River

Tuppal &

BullataleCreeks

Goulburn River

Broken Creek

Lake Eildon

Torrumbarry Weir

Goulburn Weir

Lake Victoria


Dartmouth Reservoir

Mitta Mitta River

Murrumbidgee River


Darling River


Lake Boga

Snowy Mountains


Loddon River

Finley Escape

Picnic Point

Kiewa River

Ovens River


Edward

Escape



Discussions held with MIL and State Water as a part of this phase of the Barmah Choke Study

raised concerns about the cost of constructing the proposed storage. An alternative option

presented involves construction of a storage on the site of an existing basalt quarry located to

the north of The Drop adjacent to the Berrigan Main Channel. The existing capacity of the

quarry is 1 GL, and supplementary bank works could increase the capacity up to 5 GL.

This option considers both proposals. The operating strategy for the storage (all sizes) would

be to fill the storage up to capacity (limited by the capacity of the inlet infrastructure) to avoid

River Murray flows greater than 10,600 ML/day throughout the unseasonal flooding period

and then drawndown following the end of the event by supplying downstream irrigators

(limited by the capacity of the outlet infrastructure).

This option considers four sub-options (alternative storage capacities):

Option 7a: storage capacity of 1 GL (using quarry)

Option 7b: storage capacity of 5 GL (using quarry with banks to increase capacity)

For Option 7a and 7b: inlet capacity of 1,000 ML/day, outlet capacity of 500 ML/day

Option 7c: storage capacity of 11 GL (purpose built storage)

Option 7d: storage capacity of 16 GL (purpose built storage)

For Option 7c and 7d: inlet capacity of 9,000 ML/day (note, inlet would be further

restricted by the volume of spare channel capacity on Mulwala Canal, outlet capacity

of 3,000 ML/day)

Modelling outcomes

Constructing a storage at The Drop on Mulwala Canal would enable rainfall rejections and

unregulated flows during the unseasonal flooding period to be diverted from the River Murray

at Lake Mulwala, upstream of the Barmah Choke provided there was available channel

capacity in the Mulwala Canal. This would be expected to reduce unseasonal flooding of the

Barmah-Millewa Forest. Development of storage at The Drop would also be expected to lead

to water savings through capture and re-regulation of rainfall rejection flows.


number of years each side of the Barmah-Millewa Forest is wet unseasonally of 13% to 20%

for a 1 GL or 5 GL storage respectively (Option 7a and Option 7b respectively), and 55% to

56% for a 11GL or 16 GL storage respectively (Option 7c and Option 7d, respectively)

Due to the spreadsheet based assessment approach adopted for this option, the impact on

shortfalls and other key project issues has not been simulated. However, as this option does not

involve transferring additional flow to downstream of the choke during shortfall events, this

option is not expected to impact on shortfalls or the delivery of environmental flows. This

option does not impact on the total volume of water which must be transferred from upstream



to downstream of the Barmah Choke to meet irrigation demands (it is assumed that the water

harvested in the storage would be used to meet demands in the MIL system rather than being

transferred through to the River Murray System). As such, this option is not expected to impact

on constraints on water trade.







tourism, management and emergency response, by reducing the risk of key access paths being


Forest.

In modelling this option the storage would be operated primarily to meet the objectives of the

Barmah Choke Study, but may also be complimentary to the MIL system operations. The

water released from storage would be available for diversion from the MIL channel system

enabling the system to recommence operations following a rainfall rejection without delay.

There may be added complexity to water accounting for volumes of water diverted, stored and

released from the MIL system.

However, the construction of a storage at The Drop may have some negative impacts on:

groundwater recharge and downstream salinity: groundwater in the area surrounding the

proposed storage is very high in salinity (17,000 to 30,000 EC) and is generally close to

the land surface (GHD, 2007). Surcharge of groundwater levels due to seepage from the

storage may lead to salinisation problems for surrounding landholders (GHD, 2007). GHD

(2007) considered options 7c and 7d only, however this risk is also relevant for options 7a

and 7b. The design and construction of the storage would need to include a suitable liner

to minimise this risk.

hydro-power generation: the proposed option may lead to a slight reduction in flow

through The Drop, reducing the potential for hydro-power generation through the power

station at the structure.

Water quality: options 7a and 7b are proposed to use an old basalt quarry for storage;

water quality risks associated with releasing water stored in the quarry would need to be

considered.



Option 7: storage at The Drop on Mulwala Canal

Description

Option considers construction of a storage at The Drop on Mulwala Canal. Two sites

considered: at The Drop (two larger volume sub-options) and at the soon to be

decommissioned basalt quarry site adjacent to the Berrigan Main Channel (two

smaller volume sub-options).

The storage would be operated empty as much as possible to provide airspace for

capturing rainfall rejections. The storage would be filled to avoid River Murray flows

greater than 10,600 ML/day throughout the unseasonal flooding period and rapidly

drawn down following the end of the event.

Alternative storage capacities are considered:

◦ Option 7a: storage capacity of 1 GL

◦ Option 7b: storage capacity of 5 GL

◦ For Option 7a and 7b: inlet capacity of 1,000 ML/day, outlet capacity of

500 ML/day

◦ Option 7c: storage capacity of 11 GL

◦ Option 7d: storage capacity of 16 GL

◦ For Option 7c and 7d: inlet capacity of 9,000 ML/day (note, inlet would be

further restricted by the volume of spare channel capacity on Mulwala Canal,

outlet capacity of 3,000 ML/day)

Modelling outcomes

reduce the number of years each side of the Barmah-Millewa Forest is wet

unseasonally by 13% (Option 7a), 20% (Option7b), 55% (Option 7c) and 56% (Option

7d)

no impact on shortfalls, the delivery of environmental flows or constraints on water

trade



Millewa forest

opportunity to conserve water resources (capture rainfall rejections)

opportunity for slight improvements to MIL service levels

risk of increased groundwater recharge leading to land salinisation in the immediate

vicinity of the storage

risk of reductions in hydro-power generation



3.10. Option 8: construction of a mid-river storage

Option description

As a part of the Victorian government‟s water savings initiatives, Lake Mokoan on the Broken

River has been decommissioned. This has lead to an increase in unregulated flows entering the

River Murray from the Broken River via the Goulburn River. To re-regulate these flows to

enable savings to be transferred to the Snowy River, additional use is being made of four mid-

river storages in the Torrumbarry irrigation area: Lake Boga, Kangaroo Lake and Lake Charm

which will be used to storage additional water and Kow Swamp which will be used as a part of

the harvesting process. Figure 3-11 shows the location of Lake Boga and the Torrumbarry

irrigation area on a schematic diagram of the River Murray System.


Lake Boga and the Torrumbarry irrigation area.

The mid-river storage project has been implemented by Goulburn-Murray Water together with

their project partners: the (Victorian) Department of Sustainability and Environment and the

Goulburn Broken Catchment Management Authority. The majority of the on-ground works

required for this option were constructed in 2008 and 2009 and the project commenced

operation in 2010.

The operational objectives for the mid-river storage project (storages are filled from May to

October each year with unregulated flows and drawn down during the irrigation season to meet

demands) are complementary to the objectives of the Barmah Choke Study.

Whilst this option has already been implemented by the Victorian government, the operation

of this option is not included in the modelling benchmark scenario adopted for the „do nothing‟

option as it is a part of the Victorian government‟s commitment to The Living Murray program

and cannot be modelled without also modelling implementation of other components of The

Living Murray program.

Mid-River Storage(in the Torrumbarry Region)

Tocumwal

Mulwala Canal


BARMAH CHOKE



Wakool River

Murray River


Forests

NSW-VIC-SA Border


Campaspe River


Goulburn River

Broken Creek

Lake Eildon

Torrumbarry Weir

Goulburn Weir

Lake Victoria


Dartmouth Reservoir

Mitta Mitta River

Murrumbidgee River


Darling River


Lake Boga

Snowy Mountains


Loddon River

Finley Escape

Picnic Point

Kiewa River

Ovens River


Edward

Escape



Whilst this option is currently operational, it is not included in the base case model. As such,

this option has not been modelled at this stage. If appropriate, assessment of this option may be

considered at a later stage.

Preliminary issues assessment

The construction of a mid-river storage within the Torrumbarry irrigation area has increased

the volume of water in storage mid-river which may be used to supply peak demands in the

Torrumbarry irrigation area when demands exceed the capacity of the National Channel and

both the Torrumbarry and Sunraysia irrigation areas when sufficient water cannot be supplied

from upper system storages. This option would be expected to be able to respond rapidly

providing a small to moderate volume of water to mitigate shortfalls. As such, this option

would be expected to lead to a reduction in the incidence and magnitude of peak demand

(type I) shortfall events.

This option has not been modelled, but is expected to reduce unseasonal flooding due to the

fact that the proposed operation of the storage is to release regulated flow to the River Murray

during summer. Therefore less flow will need to be passed through the Barmah Choke at some

times during Summer, potentially reducing the magnitude of unseasonal flooding events if they

occur at the same time as releases are made from the mid-Murray storage and flow through the

Barmah Choke has been reduced as a consequence.The option is unlikely to significantly

impact on the delivery of environmental flows. As additional water is supplied from

downstream of the Choke, and a related reduction in flow supplied from the Snowy system

upstream of the Choke there is potential for a reduction in the constraints on water trade.




impacts.

The potential risks and opportunities of this option were investigated by the Victorian

government prior to implementation. These investigations found that this option may pose the

following risk of impacts on a limited number of landholders downstream of Kangaroo Lake

(inundation of land) and irrigators downstream of Lake Boga (reduced service) (G-MW,

2007a) but will offer the following opportunities:

improve the recreational value of the Kerang Lakes, “recreational and tourism users at the

lakes will have more certainty about water levels because of water being stored there each

year, particularly at Lake Boga,” (G-MW n.d.)

“minimal impact on.....the operation of the Torrumbarry irrigation area” (G-MW, n.d.) in

terms of operations, and positive social and economic impacts for the irrigation area (for

both irrigators and the wider regional population)



“minimal impact on the [wider] Kerang Lakes environment...” (G-MW, n.d.), and the

increased flow through the Kerang Lakes associated with this option is expected to reduce

salinity and improve general water quality in several of the Kerang Lakes (including Lake

Boga, Kangaroo Lake and Lake Charm) (G-MW, 2007b).

Option 8: construction of a mid-river storage

Description

Whilst this option is currently operational it is not included in the base case model and

as such has not been modelled at this stage

Option would consider the impact of the operation of the mid-river storage (current

operational objectives) on the magnitude of the issues associated with the limited

capacity of the Barmah Choke

Expected results for Key Issues

reduce the incidence and magnitude of peak demand (type I) shortfall events




reduce the incidence and magnitude of peak demand (type I) shortfalls leading to

social and economic benefits

minimal risk to the operation of the Torrumbarry irrigation area

improve the recreational value of the Kerang Lakes region, particularly Lake Boga

minimal risk of impact on the wider environment of the Kerang Lakes with some

opportunity for improvements to salinity and general water quality in several lakes

risk of increases in salinity in the River Murray downstream of the mid-river storage



3.11. Option 9: Bullatale Creek bypass

Option description

Bullatale Creek is located to the north of the River Murray. Bullatale Creek receives water

from a number of streams which offtake from the River Murray between Tocumwal and Picnic

Point including Deep Creek, Aratula Creek, Lower Toupna Creek and Aluminy Creek (the

connecting creeks) and discharges to the Edward River just upstream of Tuppal Creek.

This option provides the potential to bypass rainfall rejection (and other summer unregulated)

flows through the Bullatale Creek system and the Edward River to avoid unseasonal flooding

of the Barmah-Millewa Forest. Figure 3-12 shows the proposed bypass route through Bullatale

Creek and the Edward River.

Figure 3-12: Schematic diagram of the River Murray System showing the proposed

bypass route through Bullatale Creek.

SKM (2006a) investigated the potential for the Bullatale Creek bypass to divert rainfall

rejections around the Barmah Choke. Early investigations for SKM (2006a) determined that of

the connecting creeks, Lower Toupna Creek and Aratula Creek were the most efficient

systems for diversions based on the scale of works required to divert flows. Further

investigations (SKM, 2006a) determined that from an environmental perspective it was more

suitable to divert flows through Lower Toupna Creek than Aratula Creek.

Based on this assessment, the proposed bypass route for the Barmah Choke Study is diversion

of flow from the River Murray at Lower Toupna Creek with water passing to Bullatale Creek

and on to the Edward River. This proposed bypass route through Bullatale Creek is shown in

Figure 3-13.

Bullatale Creek(proposed bypass route)

Tocumwal

Mulwala Canal


BARMAH CHOKE



Wakool River

Murray River


Forests

NSW-VIC-SA Border


Campaspe River


Goulburn River

Broken Creek

Lake Eildon

Torrumbarry Weir

Goulburn Weir

Lake Victoria


Dartmouth Reservoir

Mitta Mitta River

Murrumbidgee River


Darling River


Lake Boga

Snowy Mountains


Loddon River

Finley Escape

Picnic Point

Kiewa River

Ovens River


Edward Escape



Figure 3-13: Schematic diagram of the Bullatale Creek system showing the

proposed bypass route through Lower Toupna Creek to Bullatale Creek.

SKM (2006a) investigated four alternative bypass capacities: 750 ML/day, 1,400 ML/day,

2,500 ML/day and 3,000 ML/day. A cost per event diverted analysis undertaken as a part of

SKM (2006a) found that bypass capacity options between 750 ML/day to 2,500 ML/day had

similar costs per event diverted, while larger options became less cost effective.

Following the Option Review Workshop (16 June 2010), it was determined that this option

should be „parked‟ and not considered further at this stage of the Barmah Choke Study (this

does not preclude this option from being considered at a later stage). A National Park has

recently been established covering most of the Millewa Group State Forests. This proposed

bypass route travels through the National Park and associated works may not be appropriate in

a National Park. As such, this option will not be assessed at this stage. This decision may be

revised in the future.


Development of a bypass route using Bullatale Creek would enable rainfall rejections and

unregulated flows to be diverted from the River Murray upstream of the Barmah Choke. This

would be expected to reduce unseasonal flooding of the Barmah-Millewa Forest. Bypassing

unseasonal floods around the Barmah Choke may also lead to water savings, as the water can

be used downstream, however due to losses along the bypass route the magnitude of savings

may not be significant.

Whilst the primary aim of the bypass route would be to manage unseasonal flooding, there

may also be the potential to utilise the bypass route to supplement existing channel capacity to

meet peak irrigation demands, thus reducing peak demand (type I) shortfalls. The potential for

using the Bullatale Creek bypass route to mitigate shortfalls may be limited by losses, travel

times along the bypass route and the environmental impact associated with diverting water

through the Edward River.

TocumwalPicnic Point

Bullatale Creek

Edward River

River Murray

Deep Creek

Aluminy Creek

Lower Toupna Creek

Aratula Creek

Proposed Bypass Route



If this bypass route is used to supplement existing channel capacity constraints it may also be

possible to use this route to supply environmental flows. However, the potential of this option

to supply environmental flows will be limited by the capacity of the bypass route in

comparison to the volume of environmental flows required and as mentioned above, losses,

travel times along the bypass route and the environmental impact associated with diverting

water through the Edward River. As such, this option is not expected to impact on constraints

on water trade.







tourism, management and emergency response by reducing the risk of key access paths being


Forest.

There may also be the potential opportunity to use this option to supplement existing channel

capacity to meet peak irrigation demands. This may help lead to a reduction in the incidence

and magnitude of peak demand (type I) shortfall events, which may have a number of positive

social and economic impacts. However, this potential opportunity may be limited by a number

of factors including:

losses along the bypass route

travel times along the bypass route

availability of channel capacity

environmental impact associated with diverting water through the Edward River (see

below).

The provision of additional water to Bullatale Creek may affect the ecological condition of the

Creek and surrounding areas. SKM (2006d) assessed the ecological impacts of the proposed

Bullatale Creek bypass finding that the proposed options were “unlikely to improve or degrade

the ecological condition of Bullatale Creek, as this creek [Bullatale] currently flows for much

of the time and is currently in good condition” (page 19).

However, water diverted through Bullatale Creek will flow on through the Edward River. This

may have impacts on flow conditions in the Edward River and the Werai Forest. The operation

of this option may be limited by the available capacity in the Edward River and care would

need to be taken to ensure that bypass diversions do not contribute to undesirable flooding of



the Werai Forest. Conversely, this option may also provide opportunity to deliver beneficial

flooding to the Werai Forest and the Eastern Millewa Forest.

Option 9: Bullatale Creek bypass

Description

Modelling of this option is currently parked and will not be considered further at this

stage as this option would require works which are unlikely to be appropriate in a

National Park.

Option would consider a potential bypass route through the Bullatale Creek system

with a capacity of between 750 ML/day and 3,000 ML/day primarily used to avoid

unseasonal flooding of the Barmah-Millewa Forest

Expected Results for Key Issues

reduce unseasonal flooding of the Barmah-Millewa Forest

save water (may be offset by losses along the bypass route)

potential opportunity to reduce peak demand (type I) shortfalls



improve the health, recreational value of, and access to, the Barmah-Millewa Forest

reduce the incidence and magnitude of peak demand (type I) shortfalls leading to

positive social and economic impacts

no significant impact (positive or negative) on the ecological condition of Bullatale

Creek

risk of increased unseasonal flooding of the Werai Forest

deliver environmental water to the Werai Forest and the Eastern Millewa Forest



3.12. Option 10: Victorian forest channels

Option description

Between Tocumwal and the Barmah Choke there are a number of major creek systems which

can offtake water from the River Murray. On the Victorian side, these creeks travel through the

Barmah Forest, returning to the River Murray between Picnic Point and the Barmah township.

This option considers the potential to use the major creek systems on the Victorian side of the

Barmah Forest to avoid unseasonal flooding of the Barmah-Millewa Forest. Figure 3-14 shows

the general location of the proposed Victorian forest channels bypass route.

Two potential bypass routes have been indentified (Figure 3-15):

Kynmer Creek route: Kynmer Creek diverts from the River Murray at the upstream end of

the Barmah Forest. Kynmer Creek flows into the upstream end of Tullah Creek, which

travels around the southern side of the Barmah Forest before discharging into the Barmah

Lakes.

Gulf Creek route: Gulf Creek diverts from the River Murray approximately half way

between Tocumwal and Picnic Point. Gulf Creek travels directly through the Barmah

Forest to Tullah Creek, which travels around the southern side of the Barmah Forest

before discharging into the Barmah Lakes.

Figure 3-14: Schematic diagram of the River Murray System showing the general

location of the proposed Victorian forest channels bypass options.

Victorian Forest Channels(proposed bypass route)

Tocumwal

Mulwala Canal


BARMAH CHOKE



Wakool River

Murray River


Forests

NSW-VIC-SA Border


Campaspe River


Goulburn River

Broken Creek

Lake Eildon

Torrumbarry Weir

Goulburn Weir

Lake Victoria


Dartmouth Reservoir

Mitta Mitta River

Murrumbidgee River


Darling River


Lake Boga

Snowy Mountains


Loddon River

Finley Escape

Picnic Point

Kiewa River

Ovens River


Edward Escape



Figure 3-15: Schematic diagram of key Victorian forest channels showing two

potential bypass routes.

The bypass capacity of each route is currently unclear, however the capacity of the Gulf Creek

regulator is 2,500 ML/day and a very early study (RMC, 1980) indicated that up to

2,500 ML/day could be passed through either bypass route.

For the modelling, it is assumed that up to 2,500 ML/day could be bypassed through the

Victorian forest channels using either the Kynmer Creek route or the Gulf Creek route or a

combination of both (both routes use the downstream section of Tullah Creek and would be

limited by its capacity). However detailed hydraulic modelling would be required to confirm

the potential bypass capacity.

Modelling outcomes

The development of a bypass route using the Victorian forest channels would enable

unseasonal floods to be diverted from the River Murray upstream of the Barmah Choke. This



be used downstream.

Modelling results (see Section 6) indicate that this option would lead to a 35% reduction in the

number of years each side of the Barmah-Millewa Forest is wet unseasonally.


may be potential to utilise the bypass route to supplement existing channel capacity to meet

peak irrigation demands thus reducing peak demand (type I) shortfalls. The suitability of using

the Victorian forest channels bypass route to mitigate shortfalls may be limited by the

magnitude of losses along the route and environmental impact of additional summer flows

through the forest.

Tocumwal

Picnic Point

River Murray

Barmah Choke

Kynmer Creek

Tullah Creek

Barmah Lake

Tullah Creek

Gulf Creek

Proposed Bypass Routes



The operating rules for modelling this option did not allow the channel capacity to be used to

supplement existing channel capacity. As such the modelling results (see Section 6) do not

indicate that this option would impact on shortfall events.

The modelling results indicate that this option would not have a significant impact on the

delivery of environmental flows (indicated by the incidence of beneficial flooding of TLM

icon sites). Additionally, as it is unlikely that this bypass route would be suitable to supplement

existing channel capacity to supply peak irrigation demands (due to the magnitude of losses

and the environmental impact of additional summer flows through the forest) it is unlikely that

this route would be suitable to reduce constraints on water trade.






recreational sites being inundated. This may improve the recreational value of, and access to,


These potential opportunities could be compromised by the risk that the operation of the

bypass routes will lead to flooding; if the capacity of the bypass route is exceeded, it may

result in flooding in certain parts of the forest. This would be a serious risk which would need

careful management. Early studies recognised that works may be required at certain locations

along the proposed bypass routes to ensure bypass flows remain in channel. These works may

include additional regulators and levees.

The potential impacts associated with flooding along the bypass routes are believed to be less

for the Kynmer Creek route which follows the southern boundary of the Barmah Forest than

for the Gulf Creek route which cuts directly through a portion of the forest (RMC, 1980). In

particular, SKM (2006c) noted that wetlands along the Gulf Creek have been identified as

being of high ecological value, and thus despite being one of the largest regulators on the

Victorian side, it is operated only as a last resort.

The creeks along the proposed bypass routes are typically ephemeral, flowing in winter and

spring and dry during summer. Diverting unseasonal floods through these creeks may

significantly affect the natural flow regime and have negative impacts on their environmental

condition and ecology.

There would be potential opportunity to use this option to supplement existing channel

capacity to meet peak irrigation demands. The Gulf Creek bypass route has been used for this

purpose on two previous occasions (1994 and 2002). However, the high ecological cost of



passing summer flows through the Barmah Forest means this option would be unlikely to be

suitable on a regular basis.

It should also be noted that this option would require extensive works (construction of

regulators and levees plus channel works) through the Barmah Forest National Park. Similarly

to Option 9 (Bullatale Creek bypass), such works may not be appropriate in a National Park.

Option 10: Victoria forest channels

Description

This option considers a bypass route through the Victorian forest channels with a

bypass capacity of 2,500 ML/day

The bypass would be operated up to capacity to avoid unseasonal flooding of the


Modelling outcomes


unseasonally

potential opportunity to reduce peak demand (type I) shortfalls (not modelled) (may be

limited by the environmental impact of additional summer flows)




Millewa Forest

risk that the above benefits could be compromised if the operation of the bypass leads

to flooding along the bypass route

unlikely to be appropriate to operate the bypass to manage shortfalls on a regular

basis

option will require works which may not be appropriate in a National Park



3.13. Option 11: increased escape capacity to the Wakool River

Option description

The Wakool River is an anabranch of the River Murray diverting from the Edward River

downstream of Deniliquin and returning downstream of Werai Forest. The Wakool River can

receive water from a number of sources including from the Edward River via the Wakool and

Yallakool Offtakes and Colligen Creek and from the Mulwala Canal via the Wakool River

Escape.

This option considers the potential to bypass rainfall rejections (and other summer unregulated

flows) through the Wakool River via the Mulwala Canal to avoid unseasonal flooding of the

Barmah-Millewa Forest. Figure 3-16 shows the proposed bypass route through the Mulwala

Canal and the Wakool River.

Figure 3-16: Schematic diagram of the River Murray System showing the proposed bypass route through the Wakool River.

The MIL has, on occasion, used the Wakool River Escape from Mulwala Canal to bypass

rainfall rejections and unseasonal flows around the Barmah Choke. The use of this bypass

route is limited by the capacity of the Wakool River Escape (500 ML/day), which is often

operated at capacity during the peak of the irrigation season, to supply downstream irrigation

demands which are less impacted by rainfall rejections (SKM, 2006c). The reduced impact of

rainfall events is because many of the irrigators (e.g. rice farmers) supplied via the Wakool

River have sufficient capacity to take orders for water during rainfall events, which in other

areas would normally lead to rainfall rejections.

SKM (2006c) investigated the potential to double the existing capacity of the Wakool Escape

(500 ML/day of additional capacity for a total capacity of 1,000 ML/day).



Modelling outcomes

Development of a bypass route using the Wakool River would enable rainfall rejections and



unseasonal floods around the Barmah Choke may also lead to water savings. RMC (1980)

determined that loses along this bypass route are 20% compared with 10% along the normal

River Murray flow path.



meet peak irrigation demands and reduce the risk of peak demand (type I) shortfalls. This

option may be limited by available capacity within the MIL channel system during the

irrigation season and travel times along the bypass route.


number of years each side of the Barmah-Millewa Forest is wet unseasonally and a 7%

reduction in the number of years with shortfall events (due to a reduction in the number of

years with peak demand (type I) shortfall events).



icon sites). Additionally, if this bypass route is used to supplement existing channel capacity

constraints it may also be possible to use this route to reduce constraints on water trade.

However, as with using this option to manage shortfalls, the potential of this option to reduce

constraints on water will be limited by the availability of the option during the peak irrigation

season. As such, this option is not expected to impact on constraints on water trade.






recreational sites being inundated.

There may also be potential opportunity to use this option to supplement existing channel

capacity to meet peak irrigation demands. This may lead to a reduction in the incidence and

magnitude of peak demand (type I) shortfall events, which may have a number of positive

social and economic impacts. Duplicating the existing capacity of the Wakool River Escape

would provide an additional 500 ML/day escape capacity which may be utilised to supplement

existing channel capacity, however the use of this option may be limited by available capacity

in the MIL channel system and travel times along the route. Additionally, there are also



currently capacity constraints on the Wakool River at various points ranging from 200ML/day

to 600ML/day which cause issues with access to private property (StateWater) which may

limit the suitability of this option.

Historically, water quality has been an issue in the lower Wakool River, with saline water

accumulating in deep pools from groundwater intrusion. High flows through the Wakool River

may flush out these pools, mobilising higher salinity water (SKM, 2006c). There are also risks

associated with blackwater events in this system, particularly following prolonged dry periods.

Whilst these are natural processes (Green, 2001), the flexibility of river operations to mitigate

negative effects is increasingly being explored. Increased escape capacity to the Wakool River

may be one such „operational lever‟ to assist the delivery of dilution flows to mitigate poor

water quality events.

Option 11: increased escape capacity to the Wakool River

Description

This option considers increasing the capacity of the Wakool Escape from 500 ML/day

to 1,000 ML/day and operating a bypass route through Mulwala Canal to the Wakool

River via the Wakool Escape to avoid unseasonal flooding of the Barmah-Millewa

Forest

Modelling outcomes


unseasonally

7% reduction in the number of years with shortfall events, due to a reduction in the

number of years with peak demand (type I) shortfalls




Millewa Forest

potential opportunity to reduce the incidence and magnitude of peak demand (type I)

shortfalls leading to positive social and economic impacts

opportunity to assist with mitigation of blackwater (and other poor water quality)

events for the Wakool River.

opportunity to increase delivery of water through the system for environmental

purposes



3.14. Option 12: increased escape capacity to the Edward River

Option description

The Edward River is an anabranch of the River Murray, diverting from the river near Picnic

Point upstream of the Barmah Choke and returning just upstream of Euston Weir. The Edward

River can receive water from a number of sources including the River Murray (at Picnic Point

via the Edward River and Gulpa Creek Offtake) and from Mulwala Canal via the Edward

River Escape at Lawson‟s siphon.


flows) through the Edward River via the Mulwala Canal to reduce unseasonal flooding of the

Barmah-Millewa Forest. Figure 3-17 shows the proposed bypass route through the Mulwala

Canal and the Edward River.

Figure 3-17: Schematic diagram of the River Murray System showing the proposed bypass route through the Edward River.

Since the early 1980‟s river operators have, on occasion, used this bypass route during rainfall

rejection events and to supplement existing channel capacity to transfer water from Hume to

Lake Victoria (SKM, 2006c). However, the use of this option is currently limited by the

capacity of the escape (2,100 ML/day to 2,400 ML/day depending on season) which is often

nearly fully utilised during high demand irrigation seasons5.

SKM (2006c) investigated a proposal to increase the capacity of the escape to 3,200 ML/day

(800 ML/day additional capacity) to provide additional capacity to bypass rainfall rejection

5 MIL have historically often been constrained by the need to meet high irrigation demands even during

a rainfall rejection event (SKM, 2006c).

Tocumwal

Mulwala Canal


BARMAH CHOKE



Wakool River

Murray River


Forests

NSW-VIC-SA Border


Campaspe River


Goulburn River

Broken Creek

Lake Eildon

Torrumbarry Weir

Goulburn Weir

Lake Victoria


Dartmouth Reservoir

Mitta Mitta River

Murrumbidgee River


Darling River


Lake Boga

Snowy Mountains


Loddon River

Finley Escape

Picnic Point

Kiewa River

Ovens River


Edward Escape

Edward River(proposed bypass route)



flows. This study found it to be an effective option to reduce the incidence of unseasonal

flooding of the Barmah-Millewa Forest.

There is concern that increasing the capacity of the Edward River Escape may lead to an

increase in unseasonal flooding of the Werai Forest (downstream of Stevens Weir). Key

stakeholders (MIL and State Water) suggested that there is currently greater capacity to extract

water from Stevens Weir than to deliver water into Stevens Weir. The estimate was that the

capacity of the Edward River Escape could be increased by up to 2,000 ML/day.

This option considers three alternative sub-options (alternative bypass capacities):

Option 12a: increase the escape capacity to 3,200 ML/day (800 ML/day additional

capacity)

Option 12b: increase the escape capacity to 3,900 ML/day (1,500 ML/day additional

capacity)

Option 12c: increase the escape capacity to 4,400 ML/day (2,000 ML/day additional

capacity)

Modelling outcomes

Development of a bypass route using the Edward River would enable rainfall rejections and




be used downstream. RMC (1980) determined that losses along this bypass route are 20%

compared with 10% along the normal River Murray flow path.



meet peak irrigation demands, thus reducing peak demand (type I) shortfalls. This option may

be limited by available capacity in Mulwala Canal during the irrigation season and the risk of

environmental impacts on the Werai Forest.

Modelling results (see Section 6) indicate that this option would lead to a 19% (Option 12a),

29% (Option 12b) or 33% (Option 12c) reduction in the number of years each side of the

Barmah-Millewa Forest is wet unseasonally and an 18% (all sub-options) reduction in the

number of years with shortfall events (due to a reduction in the number of years with peak

demand (type I) shortfall events).









season and the impact of the bypass of unseasonal flooding of the Werai Forest. As such, this

option is not expected to impact on constraints on water trade.







There may also be potential opportunity to use this option to supplement existing channel



social and economic impacts; however the use of this option may still be limited by available

capacity in the MIL channel system. This option may also provide additional operational

flexibility to manage increased flow to the Edward-Wakool River system for water quality,

environmental and other purposes.

A risk associated with this option would be the potential to increase unseasonal flooding of the

Werai Forest. The Edward River passes through the Werai Forest downstream of Deniliquin.

High flows through this area that exceed that capacity of the channel (2,900 ML/day

downstream of Stevens Weir) can lead to unseasonal flooding of the Werai Forest.

Investigations undertaken as a part of SKM (2006c) indicated that this option may lead to a

significant increase in the number of years with unseasonal flooding of the Werai Forest. This

risk was investigated and the option was modelled such that the operation of the bypass would

not cause additional unseasonal flooding of the Werai Forest.



Option 12: increased escape capacity to the Edward River

Description

This option considers increasing the capacity of the Edward Escape from

2,400 ML/day and operating a bypass route through Mulwala Canal to the Edward

River via the Edward Escape to avoid unseasonal flooding of the Barmah-Millewa

Forest as follows:

◦ Option 12a: increase the escape capacity to 3,200 ML/day (800 ML/day additional

capacity)

◦ Option 12b: increase the escape capacity to 3,900 ML/day (1,500 ML/day

additional capacity)

◦ Option 12c: increase the escape capacity to 4,400 ML/day (2,000 ML/day


Modelling outcomes

19% (Option 12a), 29% (Option 12b) or 33% (Option 12c) reduction in the number of

years each side of the Barmah-Millewa Forest is wet unseasonally

18% reduction in the number of years with shortfall events (due to a reduction in the

number of years with peak demand (type I) shortfalls)




Millewa Forest



risk of an increase in unseasonal flooding of the Werai Forest, to be managed by

constraining the use of the option to avoid this risk

potential to assist management of increased flow to the Wakool River system



3.15. Option 13: increased escape capacity to Broken Creek

Option description

Broken Creek enters the River Murray downstream of Barmah Lake. In addition to upper

catchment inflows, lower Broken Creek can receive inflows via discharges (outfalls) from the

East Goulburn Main Channel (Shepparton irrigation area) and channels in the Murray Valley

irrigation area which is supplied from the Yarrawonga Main Channel.


flows) around the Barmah Choke through the Yarrawonga Main Channel and the Murray

Valley irrigation area channels to the Broken Creek. It may also be used to supplement

existing channel capacity to meet peak irrigation demands and manage shortfalls. Figure 3-18

shows the proposed bypass route through the Murray Valley irrigation area and Broken Creek.

Figure 3-18: Schematic diagram of the River Murray System showing the proposed bypass route through Broken Creek.

The river operators have, on occasion, used this bypass option to transfer water to Broken

Creek. However, this option is limited by channel capacity constraints within the Murray

Valley irrigation area, the capacity of the escape (300 ML/day) and capacity constraints within

Broken Creek which already receives outfalls from the East Goulburn Main Channel to supply

private diverters (approximately 100 ML/day). In the spring of 2006, the MDBC had limited

access to this option due to channel capacity constraints despite low allocations.

This option was investigated as a part of SKM (2006b), which identified the following

potential configuration: works to increase the capacity of the Yarrawonga Main Channel and

Murray Valley Channel 3 by 300 ML/day plus construction of a 300 ML/day link channel

between Murray Valley Channel 3 and Boosey Creek near Katamatite. Preliminary

investigations of Boosey Creek capacity and flow in Broken Creek as a part of SKM (2006b)

Tocumwal

Mulwala Canal


BARMAH CHOKE



Wakool River

Murray River


Forests

NSW-VIC-SA Border


Campaspe River


Goulburn River

Broken Creek

Lake Eildon

Torrumbarry Weir

Goulburn Weir

Lake Victoria


Dartmouth Reservoir

Mitta Mitta River

Murrumbidgee River


Darling River


Lake Boga

Snowy Mountains


Loddon River

Finley Escape

Picnic Point

Kiewa River

Ovens River


Edward

Escape

Broken Creek(proposed bypass route)



found that the available capacity of the system downstream of the link channel would be at

least 300 ML/day during periods of peak demand.

The potential to increase escape capacity to Broken Creek was investigated as a part of the

second stage of the Northern Victorian Irrigation Renewal Project (NVIRP) works program,

with the aim of providing capacity to deliver environmental water to Broken Creek. However,

at the time of this report, this proposal is not being progressed any further.

Modelling outcomes

Development of a bypass route using the Murray Valley irrigation system and Broken Creek

would enable rainfall rejections and unregulated flows to be diverted from the River Murray

upstream of the Barmah Choke, reducing unseasonal flooding of the Barmah-Millewa Forest.

Bypassing unseasonal floods around the Barmah Choke may also lead to water savings, as the

water can be used downstream.

There is also the potential to utilise the bypass route to supplement existing channel capacity to

meet peak irrigation demands and thus reduce peak demand (type I) shortfalls. However, the

use of the Broken Creek bypass route to manage shortfalls may be limited by the available

capacity along the bypass route.


number of years each side of the Barmah-Millewa Forest is wet unseasonally and a 7%

reduction in the number of years with shortfall events (due to a reduction in the number of

years with peak demand (type I) shortfall events).
















There may also be opportunity to use this option to supplement existing channel capacity to

meet peak irrigation demands. This may help lead to a reduction in the incidence and

magnitude of peak demand (type I) shortfalls events which may have a number of positive

social and economic impacts. This potential opportunity may be limited by channel capacity

constraints along the bypass route.

Additionally, the provision of additional channel and outfall capacity in the Murray Valley

irrigation system may increase operational flexibility.

Broken Creek currently experiences water quality problems including algal blooms, de-

oxygenation and fish kills, particularly during summer months, due to low flow. The provision

of additional water to Broken Creek during summer months may improve the ecological

condition of Broken Creek.

Option 13: increased escape capacity to Broken Creek

Description

This option considers a bypass route of up to 300 ML/day through Yarrawonga Main

Channel and the Murray Valley irrigation channel system to Broken Creek to avoid

unseasonal flooding of the Barmah-Millewa Forest.

Modelling outcomes


unseasonally

7% reduction in the number of years with shortfall events, due to a reduction in the

number of years with peak demand (type I) shortfalls (limited by available capacity

along the bypass route)




Millewa Forest


shortfalls, leading to social and economic benefits

opportunity to increase operational flexibility in the Murray Valley irrigation system

opportunity to improve the ecological condition (water quality) of Broken Creek



3.16. Option 14: Barmah bypass channel

Option description

This option considers the potential for a large-scale Barmah Choke bypass. The possible

bypass would divert water from Yarrawonga Weir to the River Murray near the Barmah

township downstream of the Barmah Choke. Figure 3-19 shows an indicative bypass route.

Figure 3-19: Schematic diagram of the River Murray System showing an indicative location of the Barmah Bypass Channel.

This option may enable the diversion of rainfall rejections and unregulated flows around the

Barmah Choke and may also be used to supplement existing channel capacity to meet peak

irrigation demands and manage shortfalls.

The potential for this option has been investigated in the past by Goulburn-Murray Water as a

smaller version of the Murray-Goulburn Interconnector (Option 15); however little

information is available from these investigations for the Barmah Choke Study.

Following the Option Review Workshop, it was determined that this option should be parked

and not considered further at this stage of the Barmah Choke Study. This proposed bypass

involves a large, very high cost channel to be constructed in close proximity to the Barmah

Forest which is not expected to be a viable option at this stage. This decision may be revised in

the future should further information become available.


Development of a bypass route using a new channel from Yarrawonga Weir would enable

rainfall rejections and unregulated flows to be diverted from the River Murray upstream of the

Barmah Choke. This would be expected to reduce unseasonal flooding of the Barmah-Millewa

Forest. Bypassing unseaonal flows around the Barmah Choke may also lead to water savings

as the water can be used downstream (losses along the proposed bypass route, a new and high

quality constructed channel, are expected to be low).

Tocumwal

Mulwala Canal


BARMAH CHOKE



Wakool River

Murray River


Forests

NSW-VIC-SA Border


Campaspe River


Goulburn River

Broken Creek

Lake Eildon

Torrumbarry Weir

Goulburn Weir

Lake Victoria


Dartmouth Reservoir

Mitta Mitta River

Murrumbidgee River


Darling River


Lake Boga

Snowy Mountains


Loddon River

Finley Escape

Picnic Point

Kiewa River

Ovens River


Edward

Escape

Barmah Bypass Channel(indicative route)



The proposed bypass may also be used to supplement existing channel capacity to meet peak

irrigation demands and reduce shortfalls. The capacity of this bypass, along with the potential

to commence operations quickly and continue operations for extended periods of time mean

this option could be used to manage both peak demand (type I) and lower system storage

(type II) shortfalls.



icon sites). Depending on how this option is operated, it may be possible to use this bypass

route to deliver water from upstream to downstream of the Barmah Choke throughout the

irrigation season (including during periods of peak demand, although this may compromise the

potential to use the option to manage shortfalls). If the bypass route is used in this way,

constraints on water trade may be reduced.







This option would also be expected to lead to a reduction in the incidence and magnitude of

both peak demand (type I) and lower system storage (type II) shortfall events, which may have

a number of positive social and economic impacts.

SMEC (2002) assessed the potential impact of a similar bypass route, finding that the proposed

route would be across the natural fall of the land and through potentially unsuitable soils. This

has the potential to cause a number of flooding issues throughout the region, forming a barrier

to natural overland flow paths. Additionally, construction of such a large, long channel may

have significant environmental impacts associated with construction activities and social

impacts associated with the proposed construction route (for example acquisition of private

land).

It has also been identified that discharge of such large inflows to the River Murray just

downstream of the Barmah Choke at times of high river flows may cause backwater effects on

water levels in the Barmah Lakes (SMEC, 2002).



Option 14: Barmah bypass channel

Description

this option considers the potential for construction of a large-scale Barmah Choke

bypass diverting water from Yarrawonga Weir to the River Murray near the Barmah

township downstream of the Barmah Choke

Preliminary key issues

reduce unseasonal flooding of the Barmah-Millewa Forest

save water

reduce peak demand (type I) and lower system storage (type II) shortfalls

this option would not be expected to impact on the delivery of environmental flows or

constraints on water trade


opportunity to improve the health, recreational value of, and access to the Barmah-

Millewa Forest

opportunity to reduce the incidence and magnitude of peak demand (type I) and lower

system storage (type II) shortfalls leading to social and economic benefits

potential risk to natural overland flow paths

risk of negative environmental impacts associated with construction activities

risk of negative impacts on land holders in the vicinity of the proposed bypass route

(land acquisition)

risk of back water effects on water levels in the Barmah Lakes

opportunity to enable water trade if the operating rules for the channel were altered



3.17. Option 15: Murray-Goulburn interconnector channel

Option description

The concept of constructing a channel linking the Murray and Goulburn systems was first

investigated in the late 1980‟s. The aim of such a channel would be to provide flexibility to

deliver water from Eildon Reservoir to the Murray System in exchange for delivering water

from the River Murray System upstream of the Barmah Choke to the Goulburn system.

This option considers the potential to use a new channel to manage shortfalls. Figure 3-20

shows the proposed Murray-Goulburn Interconnector channel route.

Figure 3-20: Schematic diagram of the River Murray System showing the general location of the proposed Murray-Goulburn Interconnector channel.

The potential for this option has been investigated a number of times since it was first

proposed. Most recently, the Victorian Government undertook investigations to develop a

business case for the proposed channel to address a range of issues.

This option includes construction of a 2,400 ML/day channel extending from the Yarrawonga

Main Channel just downstream of Yarrawonga Weir to the East Goulburn Main Channel just

downstream of Broken River (upstream of the bulk of the Shepparton irrigation area) with

outlet structures at the points where it crosses Broken Creek and Boosey Creek.

This channel would be run to supply up to 2,000 ML/day to the Shepparton irrigation area over

the irrigation season (August to April) whenever there was sufficient demand. It would also be

operated to deliver up to 400 ML/day to Broken Creek via Boosey Creek (100 ML/day),

Broken Creek (100 ML/day) and the East Goulburn Main Channel Outfall to Broken Creek

(200 ML/day). Diverted water would then be returned to the River Murray System as callable

inter-valley trade credits in Lake Eildon.

Tocumwal

Mulwala Canal


BARMAH CHOKE



Wakool River

Murray River


Forests

NSW-VIC-SA Border


Campaspe River


Goulburn River

Broken Creek

Lake Eildon

Torrumbarry Weir

Goulburn Weir

Lake Victoria


Dartmouth Reservoir

Mitta Mitta River

Murrumbidgee River


Darling River


Lake Boga

Snowy Mountains


Loddon River

Finley Escape

Picnic Point

Kiewa River

Ovens River


Edward

Escape

Interconnector Channel(indicative route)

IVT Credits to the Murray System



Note, that while the Victorian Government business case was developed to address a range of

issues, the Barmah Choke Study focuses on assessing this option in relation to the issues and

outcomes associated with the Barmah Choke only. The Barmah Choke Study has not assessed

any other objectives of the proposed Murray-Goulburn Interconnector.

Modelling outcomes

The construction of the Murray-Goulburn interconnector channel would increase flexibility to

manage peak irrigation demands by increasing the volume of callable inter-valley trade credits.

This would be expected to lead to a reduction in the incidence and magnitude of shortfall

events.

The use of this option to manage peak demand (type I) shortfalls (generally large volume,

rapid onset shortfalls) may be limited by the long travel times between Lake Eildon and the

River Murray (approximately 2 weeks); however this option would be expected to provide

significant flexibility for managing lower system storage (type II) shortfalls (generally longer

in duration).


number of years with shortfall events.

This option may also increase flexibility for trade, including the potential for trade from

upstream of the Barmah Choke to the Goulburn system or downstream of the Barmah Choke.

Modelling results (see Section 6) also indicate that this option would lead to a 22% reduction

in the number of years each side of the Barmah-Millewa Forest is wet unseasonally.

Significantly increasing the volume of water delivered to the River Murray System from the

Goulburn system (via increasing the volume of inter-valley transfers) reduces pressure on the

Barmah Choke and means that the Barmah Choke may be operated at a lower level in some

years. This provides additional buffer capacity to absorb rainfall rejections within the river

channel, leading to a reduction in unseasonal flooding.



icon sites). Depending on how this option is operated, it may be possible to use this bypass

route to divert water around the Barmah Choke throughout the irrigation season (including

during periods of peak demand, although this may compromise the potential to use the option

to manage shortfalls). If the bypass route is used in this way, constraints on water trade may be

reduced.





system storage (type II) shortfall events, which may have a number of positive social and

economic impacts for these irrigation areas.

Additionally, this option may free up trade restrictions associated with the Barmah Choke, as

water from upstream of the Barmah Choke could be traded to the Goulburn system (or to parts

of the lower River Murray through back trade).

SMEC (2002) identified that the proposed bypass route would be across the natural fall of the

land and through potentially unsuitable soils. This has the potential to cause a number of

flooding issues throughout the region, forming a barrier to natural overland flow paths.

Additionally, construction of such a large, long channel may have significant environmental

impacts associated with construction activities and social impacts associated with the proposed

construction route (acquisition of private land).

Concerns also exist about the need to supply large volumes of inter-valley trade credits

through the lower Goulburn River. Water to supply trade credits is most likely to be released

through the lower Goulburn River during the summer and autumn peak of the irrigation

season. This may affect the flow regime of the lower Goulburn River.

Broken Creek currently experiences water quality problems including algal blooms, de-

oxygenation and fish kills, particularly during summer months, due to low flow. The provision

of additional water to Broken Creek during summer months may improve the ecological

condition of Broken Creek.



Option 15: Murray-Goulburn interconnector channel

Description

This option considers the potential for the construction of a 2,000 ML/day channel

extending from the Yarrawonga Main Channel to the East Goulburn Main Channel.

The channel would be run to supply the Shepparton irrigation area over the irrigation

season. Up to 400 ML/day may also be diverted to Broken Creek. Diverted water will

be returned to the River Murray as inter-valley trade credits in Lake Eildon

Modelling outcomes

43% reduction in the number of years with shortfall events

potential opportunity to reduce constraints on water trade


unseasonally

no impact on the delivery of environmental flows



shortfalls leading to social and economic benefits

opportunity to free-up trade restrictions associated with the Barmah Choke

potential risk to natural overland flow paths

risk of negative environmental impacts associated with construction activities

risk of potential impacts on the flow regime of the lower Goulburn River

opportunity to improve the ecological condition (water quality) of Broken Creek



3.18. Option 16: Perricoota Escape

Option description

The Deniboota Canal offtakes from Mulwala Canal downstream of Deniliquin and runs south-

west connecting to the River Murray just upstream of Torrumbarry Weir via the Perricoota

Escape. The canal has a capacity of 1,200 ML/day at the offtake but decreases downstream.

The Perricoota Escape originally had a capacity of 50 ML/day which was used to deliver water

through the system to the River Murray. The capacity of the escape was upgraded to

200 ML/day in 2006 to provide flexibility in diverting water around the Barmah Choke (MIL,

2007).

The 200 ML/day capacity of the Perricoota Escape, included for this option, was used until

January 2007 (MIL, 2007) but has not been used since (MIL, personal communications), and is

not used in the “do nothing” option (Option 1).


flows) through the Deniboota Canal and Perricoota Escape to avoid unseasonal flooding of the

Barmah-Milewa Forest. Figure 3-21 shows the proposed bypass route through the Deniboota

Canal and Perricoota Escape.

Figure 3-21: Schematic diagram of the River Murray System showing the proposed bypass route through the Deniboota Canal and Perricoota Escape.

The capacity of the current escape is 200 ML/day. MIL staff have suggested that it may be

possible to upgrade the capacity of Deniboota Canal and Perricoota Escape to provide

additional capacity. MIL staff suggested there would be two thresholds of additional capacity,

beyond which would require a step change in the extent of works required: 500 ML/day and

1,000 ML/day.

Tocumwal

Mulwala Canal


BARMAH CHOKE



Wakool River

Murray River


Forests

NSW-VIC-SA Border


Campaspe River

Tuppal &

BullataleCreeks

Goulburn River

Broken Creek

Lake Eildon

Torrumbarry Weir

Goulburn Weir

Lake Victoria


Dartmouth Reservoir

Mitta Mitta River

Murrumbidgee River


Darling River


Lake Boga

Snowy Mountains


Loddon River

Finley Escape

Picnic Point

Kiewa River

Ovens River


Edward

Escape

Perricoota Escape(proposed bypass route)



Modelling outcomes

Development of a bypass route using the Perricoota Escape would enable rainfall rejections

and unregulated flows to be diverted from the River Murray upstream of the Barmah Choke.

This would be expected to reduce unseasonal flooding of the Barmah-Millewa Forest.

Bypassing unseasonal flows around the Barmah Choke may also lead to water savings.


may be potential to utilise the bypass route to supplement existing channel capacity to meet

peak irrigation demands, thus reducing peak demand (type I) shortfalls. This option may be

limited by available capacity during the irrigation season.

Modelling results (see Section 6) indicate that this option would lead to up to a 9% reduction

in the number of years each side of the Barmah-Millewa Forest is wet unseasonally and up to

an 18% reduction in the number of years with shortfall events.














There may also be the potential opportunity to use this option to supplement existing channel



social and economic impacts; however the use of this option may still be limited by available

capacity in the MIL channel system. The potential for operating this option in conjunction with

the new regulator at Perricoota Forest constructed under The Living Murray program could be

investigated.



Option 16: Perricoota Escape

Description

This option considers using the Perricoota Escape (current and increased capacity) as

a bypass route through Mulwala Canal and Deniboota Canal to avoid unseasonal

flooding of the Barmah-Millewa Forest as follows:

◦ Option 16a: use the existing escape capacity (200 ML/day)

◦ Option 16b: increase the escape capacity to 500 ML/day (300 ML/day additional

capacity)

◦ Option 16c: increase the escape capacity to 1,000 ML/day (1,300 ML/day


Modelling outcomes

up to a 9% reduction in the number of years each side of the Barmah-Millewa Forest

is wet unsesonally

up to an 18% reduction in the number of years with shortfall events




Millewa Forest



potential to operate in conjunction with new regulator at Perricoota Forest



3.19. Option 17: combined weir manipulation

Option description

Operating rules currently restrict operational flexibility in a number of assets throughout the

River Murray System. Many of these rules are in place to meet operational, social or

environmental requirements and must be retained. However, there are some rules in place that

it may be possible to modify to increase operational flexibility without unacceptable

operational, social or environmental impacts.

In recent years, a number of the mid-river weirs along the River Murray System have been

operated more flexibly to avoid shortfalls. Additionally, there is a general move towards more

flexible operation of weirs for environmental purposes. In line with this, a potential

modification suitable for consideration is modest lowering of the minimum storage target for

multiple weirs in coordination, rather than a large drawdown at a single weir in isolation.

Weirs that could be manipulated include Torrumbarry Weir, Euston Weir, Mildura Weir,

Wentworth Weir, Lock 8 and Lock 9. Figure 3-22 shows the location of each weir on a

schematic diagram of the River Murray System.

Figure 3-22: Schematic diagram of the River Murray System showing the location of each weir.

The River Murray System Annual Operating Plan (MDBA, 2010c) and River Murray

operators suggested the following manipulations could be possible with existing infrastructure:

Torrumbarry Weir, maximum drawdown of 40 cm

Euston Weir, maximum drawdown of 30 cm

Mildura Weir, maximum drawdown of 25 cm

Wentworth Weir, maximum drawdown of 25 cm

Lock 8, maximum drawdown of 50 cm

Tocumwal

Mulwala Canal


BARMAH CHOKE



Wakool River

Murray River


Forests

NSW-VIC-SA Border


Campaspe River


Goulburn River

Broken Creek

Lake Eildon

Torrumbarry Weir

Goulburn Weir

Lake Victoria


Dartmouth Reservoir

Mitta Mitta River

Murrumbidgee River


Darling River


Lake Boga

Snowy Mountains


Loddon River

Finley Escape

Picnic Point

Kiewa River

Ovens River


Edward

Escape

Torrumbarry Weir

Euston Weir

Mildura Weir

Wentworth Weir

Lock 8Lock 9



Lock 9, maximum drawdown of 20 cm

This option considers operating each storage at the appropriate normal operating level

(generally full supply level) throughout the irrigation season and rapid draw down of these

weirs to avoid shortfalls by supplying demands when sufficient water cannot be supplied from

upper system storage (no change to the target operating level). The total volume of active

storage that would be available from this option is 19.2 GL.

Modelling outcomes

Lowering the minimum operating level of multiple weirs in coordination while maintaining the

target storage at full supply level would increase the mid-river storage capacity. This may be

used to supplement supply peak demands when sufficient water cannot be supplied from upper

system storages. This would be expected to reduce the incidence and magnitude of shortfall

events.


duration and of large volume) may be limited by the volume of drawdown water available.

However, this option is expected to provide flexibility for managing peak demand (type I)

shortfalls with the option providing 19.2 GL of water which can be drawn upon to mitigate a

shortfall event.


number of years with shortfall events. The majority of the reduction in the number of years

arises from reductions in the number of years with peak demand (type I) shortfall events, with

minimal impact on lower system storage (type II) shortfall event.

Due to the spreadsheet based assessment approach adopted for this option, the impact on




the weirs, this option is not expected to significantly impact on unseasonal flooding of the




downstream of the Barmah Choke to meet irrigation demands (the weirs would need to be re-

filled after each drawdown event). As such, this option is not expected to impact on constraints

on water trade.




impacts.



Lowering the minimum operating level of the selected weir pools may have some negative

impacts on recreational use of the weir pool and pumped diversions from the weir pool;

however as the maximum draw downs proposed for this option are within the current operating

range of each weir this is not expected to be a significant risk.

Option 17: combined weir manipulation

Description

Mid-river weirs would be operated at normal operating levels (generally full supply

level) throughout the irrigation season and rapidly drawn down to avoid shortfalls. The

weirs and maximum draw downs to be considered are:

◦ Torrumbarry Weir, maximum drawdown of 40 cm

◦ Euston Weir, maximum drawdown of 30 cm

◦ Mildura Weir, maximum drawdown of 25 cm

◦ Wentworth Weir, maximum drawdown of 25 cm

◦ Lock 8, maximum drawdown of 50 cm

◦ Lock 9, maximum drawdown of 20 cm

This would provide a total of 19.2 GL of water which could be drawn upon to mitigate

a shortfall event

Modelling outcomes

54% reduction in the number of years with shortfall events, primarily due to a

reduction in the number of years with peak demand (type I) shortfall events






no significant risk of negative impacts on recreational use or pumped diversions from

the weir pools



4. Option costing and risk cost analysis

4.1. Option costing

A cost estimation process was undertaken to provide the costs involved with the capital based

options. Table 4-1 provides a summary of the costing undertaken for each option.

Table 4-1: Summary of options costing.

Option Costing Status Comment

Option 1- do nothing No costing required – current conditions


No costing required – operational change only






No costing undertaken – conceptual investigation only


Cost estimate prepared

Option 5- lower operating level in Lake Mulwala

Cost estimates prepared (two sub-options)


Cost estimates prepared (three sub-options)


Cost estimates prepared for the 11 GL and 16 GL sub-options. Preliminary cost estimates for the 1 GL and 5 GL sub-options provided by MIL


No costing required – current conditions

Option 9- Bullatale Creek bypass No costing required – option not progressed

Option 10- Victorian forest channels Cost estimates prepared (two construction routes of the same capacity)




Cost estimate prepared for the 800 ML/day increase in capacity sub-option. Preliminary cost estimates for the 1,500 ML/day and 2,000 ML/day increases in capacity sub-options provided by MIL



Option 14- Barmah bypass channel No costing required – option not progressed



Option 16- Perricoota Escape Preliminary cost estimates provided by MIL

Option 17- Combined weir manipulation No costing required – operational change only



4.2. Assessment process

The base estimate involved a desk top analysis using previous cost assessments and knowledge

from similar water infrastructure projects. For this assessment allowance was made for design

costs (set to 20 per cent) and a contingency allowance.

The estimation process for calculating contingency follows a process outlined in Evans & Peak

(2008). Following this method, a contingency is used to provide coverage for a given set of

risks which should be identified in two parts:

inherent risk: relates to the risk range of measured values that make up the components of

the base estimate. This can include changes to the quantity and rates to produce a

minimum, expected and maximum cost range.

contingent risk: due to unmeasured items that can include industrial issues, safety,

planning and weather.

A contingency can be set either using a deterministic (by applying a set percentage) or a

probabilistic method. There are several methods to evaluate the contingency using

probabilistic methods including:

scenario analysis where a number of alternative options for the project are proposed,

representing the most likely situation and realistic variations from it, and risks associated

with each scenario which are analysed and compared.

decision trees that compare the various outcomes from one or more decisions in order to

identify the optimum choices when there is uncertainty about some aspect of the outcome.

Monte Carlo simulation analyses of the combined effect of estimate ranges to create a

probabilistic estimate of costs.

For this assessment, both a deterministic and probabilistic approach were used to apply a

contingency. Contingent risk is applied through a deterministic process by applying an

additional contingency of 40 per cent. In most cases, the estimates are very preliminary and

based on little data (i.e. no ground survey, no geotechnical information, no consultation, no

detailed hydraulic studies etc). Therefore this level of contingency is considered reasonable for

this stage of the consideration of options.

Calculating a contingency for inherent risk is undertaken using a probabilistic method, based

on Monte Carlo simulation. The Monte Carlo simulation in this instance models the total

project costs when the cost components are allowed to vary across a defined range between

minimum, expected and maximum. The simulation is repeated many times such that a

distribution of costs results. From this distribution an appropriate level of uncertainty can be

chosen for inclusion in the costs.



An estimate of the cost components is set using a Beta-PERT distribution based on the

minimum, maximum and most likely cost. As an example, Figure 4-1 shows the probability

distribution of the „Top soiling‟ – a cost element of the Option 10, based on the input cost data

provided in Table 4-2.

Figure 4-1: Example input cost assumption.

Table 4-2: Example cost inputs.

Quantity UNIT Price or Rates Cost Range

Min Expected Max Min Expected Max Min Expected Max

63,000 70,000 91,000 m3 $ 2.00 $ 2.00 $ 4.00 $ 126,000 $ 140,000 $ 364,000

Combining all the input cost assumptions, and running a random simulation, a probabilistic

estimate of cost results. Figure 4-2 provides an example of this. In this case, the 90th percentile

represents the cost which will not be exceeded 90 per cent of the time.



Figure 4-2: Example probabilistic estimate for Option 10b.

4.3. Summary of results

Table 4-3 provides a summary of the cost modelling undertaken. Appendix F is a detailed

breakdown of the financial analysis of the options. Both the base estimate (including design

and a 40 per cent contingency) and the 90th percentile estimate (including contingency) is

provided. A present value estimate is also given to allow meaningful comparison of options

which result in an on-going operating cost. The present value estimate is undertaken over a 20

year period with a 6 per cent discount rate. Note that no attempt to estimate or quantify

escalation over this period has been made.

The discount rate is consistent with Commonwealth guidelines; however these guidelines do

not provide a single number but rather the method for calculation. Discount rate of 7 per cent

is consistent with NSW guidelines however 6 per cent is usual in Victoria and South Australia.

The discounting is used for comparison purposes and not for investment decision so the actual

rate (within reason) is not particularly important. The 20 year period is consistent with recent

DEWHA water business case requirements. However, a 30 year period could easily be

justified. The capital costs are not discounted as it is suggested they would all be constructed in

one year which is clearly not feasible. Given this present value analysis is for broad

comparison purposes only, small modifications are not likely to influence the assessment

process.



Table 4-3: Summary of cost modelling (all estimates include contingencies).

Capital

Cost

(base

estimate)

Capital

Cost

( 90th

percentile)

Operating

cost

(base

estimate)

Operating

cost

(90th

percentile)

Present

Value

20 years

@6%

(base

estimate)

Present

Value

20 years

@6%

(90th

percentile)

Option 4: Mildura Weir $ 1.68 m $ 1.91 m - - $ 1.68 m $ 1.91 m

Option 5a: Lower operating level

Lake Mulwala by 100 mm $ 2.62 m $ 2.89 m $ 0.07 m $ 0.07 m $ 3.40 m $ 3.71 m

Option 5b: Lower operating level

Lake Mulwala by 500 mm $ 8.10 m $ 9.18 m $ 0.27 m $ 0.28 m $ 11.23 m $ 12.44 m

Option 6a: Euston Weir - Raise

the minimum operating level of

Euston Weir by 0.5 m to 48.1 m

AHD

$ 0.83 m $ 0.95 m - - $ 0.83 m $ 0.95 m

Option 6b: Euston Weir - Lower



AHD

$ 1.99 m $ 2.24 m - - $ 1.99 m $ 2.24 m

Option 6c: Euston Weir - Raise



AHD and lower the minimum

operating level of Euston Weir by

1.5 m to 46.1 m AHD

$ 2.26 m $ 2.62 m - - $ 2.26 m $ 2.62 m

Option 7c: 11 GL Storage at The

Drop on Mulwala Canal $ 56.37 m $ 63.08 m $ 1.27 m $ 1.42 m $ 70.91 m $ 79.31 m

Option 7d: 16 GL Storage at The

Drop on Mulwala Canal $ 70.14 m $ 78.66 m $ 1.49 m $ 1.67 m $ 87.23 m $ 97.81 m

Option 10a: Victorian Forest

Channels (Kynmer Creek Route) $ 90.08 m $ 109.56 m $ 0.66 m $ 0.86 m $ 97.66 m $ 119.46 m

Option 10b: Victorian Forest

Channels (Gulf Creek Route) $ 57.14 m $ 68.65 m $ 0.46 m $ 0.59 m $ 62.45 m $ 75.36 m

Option 11: Increased diversion

through the Wakool River $ 1.93 m $ 2.15 m $ 0.42 m $ 0.42 m $ 6.75 m $ 6.97 m

Option 12: Increased escape

capacity to the Edward River

(800 ML/d)

$ 2.55 m $ 3.01 m $ 0.42 m $ 0.42 m $ 7.37 m $ 7.83 m

Option 13: Increased escape

capacity to Broken Creek $ 16.54 m $ 18.48 m $ 0.34 m $ 0.37 m $ 20.43 m $ 22.71 m

Option 15: Murray Goulburn

interconnector (2000 ML/d) $ 370.35 m $ 424.86 m $ 2.09 m $ 2.62 m $ 394.27 m $ 454.92 m



4.4. Limitations

This cost assessment is provided as an input for the evaluation of options. It was undertaken

through a desktop analysis only and is therefore not suitable for making investment decisions.

Other limitations that should be considered when using the data include:

cost information is capital and operating cost estimate only. No provision is made for the

cost of project approvals

each cost item is considered independent of each other. For example, if there is a risk of

an increase in the cost of steel but this commodity is included in other line items then a

high cost for one line item may be selected at the same time as a low cost for another line

item during the same iteration of the model. This can lead to an underestimate of the

contingency as in fact the increase in the cost of an item is likely to be correlated with the

increase in cost of other items (it is possible to stochastically generate correlated variables

but this is outside the scope of the Barmah Choke Study)

using the Beta-PERT distribution suggests a greater confidence in the most likely

estimate. It can be used with a wide range between the minimum and maximum durations

as the probabilities of hitting the extremes is less than if using the Triangular distribution.

Using this distribution results in a reduced cost contingency which is appropriate if there

is confidence in the most likely estimates. The Beta-PERT distribution is a standard

approach to these types of cost estimation problems.

4.5. Costing of additional options

Preliminary cost estimates for additional options were provided by MIL. These represent the

capital cost estimates, and exclude allowances for operating and maintenance costs. To allow

the cost of these options to be compared with the cost of other options it was necessary to

estimate the present value (base estimate costs). In the absence of estimates for operating and

maintenance costs, these costs were set to 2 per cent of the capital cost estimate.

The cost estimates (capital and present value) for the following options are very preliminary

and have been presented for comparative purposes only.

Option 7a- storage at The Drop (1 GL storage): $5 million

Option 7b- storage at The Drop (5 GL storage): $10 million

Option 12b- increased escape capacity to the Edward River (1,500 ML/day additional

capacity): $6.5 million

Option 12c- increased escape capacity to the Edward River (2,000 ML/day additional

capacity): $8.0 million

Option 17b- Perricoota escape (500 ML/day capacity): $8.0 million

Option 17b- Perricoota escape (1,000 ML/day capacity): $50 million



5. Option risk assessment

5.1. Risk assessment process

The risk assessment process consists of a qualitative evaluation, following the MDBA Risk

Management Guidelines (2010a) which have been based on the joint Australia/New Zealand

Standard, AS/NZ ISO 31000:2009 (Figure 5-1). As this is a high level assessment, this process

has focussed on the Risk Assessment process (part 5.4).

Figure 5-1: Risk assessment process from AS/NZ ISO 3100 (MDBA 2010a).

5.2. Risk assessment context

The aim of the risk assessment process for the Barmah Choke Study was to provide a high

level assessment of the risks as one input to the evaluation of the options. The risk assessment

matrix used is provided in Figure 5-2.

The consequence categories from the MDBA guidelines have been used for Financial,

Stakeholder and Environmental risks. The MDBA guidelines also provide descriptions for

OH&S and Reputation risks however these risks have not been included in this assessment.

OH&S risks tend to be project specific and would be considered during project

implementation. MDBA reputation risks are also not considered at this stage of options

analysis because distinguishing between options on reputation risk is difficult.



In order to consider the full range of risks, description of consequence has also been developed

for Regulatory Requirements and Project Delivery risks. These risks are not included in the

MDBA guidelines so the consequence descriptions have been aligned as far as possible to

match the relative severity of the other consequence items.

All risks have been assessed on an unmitigated basis to aid comparison. It is acknowledged

that most (if not all) risks identified could be mitigated to an acceptable level but this may

require a commitment of resources or political capital by the MDBA and possibly the

jurisdictions.

Figure 5-2: Risk analysis matrix adapted from MDBA guidelines (2010).

Risk Items

Table 5-1 outlines the risk items that were assessed. The consequence category relates to the

consequence thresholds against which each risk item is assessed. These threshold descriptions

are provided in Figure 5-2. It is acknowledged there is some overlap in the risk items. For

example, a project with high environmental risk is likely to cause stakeholder and community

concern on environmental grounds. Likewise a high cost option will likely have a high

construction cost risk and demand/supply risk.

Consequence Rank Catastrophic Major Moderate Minor Insignificant

Financial FIN

Huge financial loss (total

dollar cost greater than

$50m)

Major financial loss (total

dollar cost in the range

$5m to $50m)

Significant financial loss

(total dollar cost in the

range $500k to $5m)

Medium financial loss (total

dollar cost in the range

$100k to $500k)

Low financial loss (total

dollar cost less than $100k)

Regulatory

requirementREG

Significant regulatory

requirements include EIS or

public inquiry with on-going

legal challenges to the

extent that it fails to have

continued political support

Significant regulatory

requirements include EIS or

public inquiry

Significant approvals

process requiring high level

ministerial approval

Moderate planning

requirements

Low level or no approvals

required

Environment ENV

Catastrophic environmental

impact which has long term

consequences and severely

impacts on the national

economy

Extensive environmental

impact over a prolonged

period which has major

political and/or economic

consequences

Significant environmental

impact but over a limited

period

Only minor, if any,

environmental impactNo environmental impact

Stakeholders and

communitySTK

Key stakeholders suffer

severe impact or loss of

confidence in the program,

and possibly the MDBA,

the extent that its future is

in question

Extensive impact on key

stakeholders with major

political ramifications

and/or extensive

community dissatisfaction

Significant stakeholder

impact which requires

executive attention and has

some political ramifications

Minor stakeholder impact

which is dealt with in a

short timeframe

Little if any stakeholder

impact

Project Delivery

riskDEL

Project unable to meet its

objectives and benefits will

not be realised

Project benefits are

impacted and some targets

not met

Permanent change in

project plan resulting in

small reduction in project

benefits.

Small changes on project

schedule not impacting

overall benefits

Small change to schedule

which are rectified during

project period

LikelihoodProject

Frequency

Semi-

Quantitative

Frequency

Environmental

FrequencyRank 1 2 3 4 5

Almost certain

More than once

during the

project.

Monthly

occurrence.

Common

occurrence, high

volume/ use.

A High High Significant Significant Moderate

LikelyOnce during

the project.

More than once

per year.

Common

occurrence, low

volume/ use.

B High Significant Significant Significant Moderate

Possible

Could happen

during the

project life.

Once every one

to 10 years.

Occasional

occurrence, high

volume/ use.

C High Significant Significant Moderate Low

Unlikely

Unlikely to

occur during

project life.

Once every 10

to 100 years.

Occasional

occurrence, low

volume/ use.

D High Significant Moderate Low Low

Rare

Very unlikely to

occur during

the project life.

Once every 100

to 1000 years.Rare occurrence. E High Significant Moderate Low Low

Determine the Consequence (C)

Risk Analysis Matrix

De

term

ine

th

e L

ike

lih

oo

d (

L)



Table 5-1: Risk Items assessed.

Risk Item Description Consequence category

Technical Feasibility

Risk that the project will not be delivered, or is technically infeasible, is influenced by the requirement for specialised personnel, methods, and equipment.

Project Delivery

Regulatory conditions

Risk the project will be subject to significant approvals process e.g., EIS or Public Inquiry from EPBC Act or requires change to the Water Act or Murray Darling Basin Agreement.

Regulatory requirement

Stakeholder and community

Risk the project is subject to significant community or stakeholder opposition.

Stakeholder and community

Demand \ supply risk

Risk that changes to irrigation demand and supply conditions mean the infrastructure is used significantly less than designed for, and potentially obsolete.

Financial

Environmental risk

Risk that project construction or operation is likely to cause unacceptable environmental damage.

Environment

Construction cost risk

Risk the project is likely to be subject to cost overruns. Financial

Operation risk Risk relating to the operational requirements to implement and control the option.

Project Delivery

5.3. Risk assessment results

The SKM project team held an internal risk assessment workshop on the 21 May 2010 to

assess each of the options against the risk items. A further workshop was help on 3 September

2010 to review the risks based on the MDBA guidelines and to respond to comments provided

by MDBA and the River Murray System Operations Review Working Group.

In this section, risk items from Table 5-2 are considered in turn and the risk rating for each of

the options is listed and described. The rationale behind the risk ratings is described,

particularly if there are any options that fall within the highest risk category.

A summary of the assessment of likelihood and consequence for each option for each risk is

provided in Figure 5-3.



Figure 5-3 Classification of risk types for each option.

Project Risks

Risk Issue Description TypeC L Risk C L Risk C L Risk C L Risk C L Risk C L Risk C L Risk C L Risk C L Risk C L Risk C L Risk C L Risk C L Risk C L Risk C L Risk


The degree to which the plans call for

specialised personnel, methods, and

equipment will impact the risks inherent in

the project

DEL 5 D Low 4 CMode

rate3 C

Signifi

cant4 C

Mode

rate4 C

Mode

rate4 D Low 4 D Low 4 D Low 4 D Low 4 D Low 4 D Low 3 C

Signifi

cant3 C

Signifi

cant3 C

Signifi

cant3 C

Signifi

cant


Risk the project will be subject to significant

approvals process e.g., EIS or Public

Inquiry from EPBC Act

REG 5 E Low 4 D Low 4 D Low 4 CMode

rate3 B

Signifi

cant3 C

Signifi

cant3 A

Signifi

cant3 A

Signifi

cant3 B

Signifi

cant3 B

Signifi

cant3 B

Signifi

cant3 B

Signifi

cant3 B

Signifi

cant3 B

Signifi

cant3 B

Signifi

cant

Stakeholders and community

Risk the project is subject to significant

stakeholder, community or political

opposition

STK 3 CSignifi

cant4 D Low 4 D Low 3 D

Mode

rate3 C

Signifi

cant2 B

Signifi

cant3 B

Signifi

cant2 A High 3 C

Signifi

cant2 B

Signifi

cant2 B

Signifi

cant3 D

Mode

rate3 D

Mode

rate3 D

Mode

rate3 D

Mode

rate


Risk that changes to irrigation demand and

supply conditions mean the infrastructure is

being used significantly less than designed

for, and potentially obsolete

FIN 5 D Low 4 D Low 4 D Low 4 D Low 4 D Low 5 D Low 5 D Low 5 D Low 5 D Low 5 D Low 5 D Low 2 DSignifi

cant2 D

Signifi

cant2 D

Signifi

cant2 D

Signifi

cant

Environmental riskIs project construction likely to cause

unacceptable environmental damageENV 2 B

Signifi

cant4 C

Mode

rate4 D Low 4 D Low 5 E Low 3 C

Signifi

cant4 C

Mode

rate4 C

Mode

rate3 C

Signifi

cant3 C

Signifi

cant3 C

Signifi

cant3 C

Signifi

cant3 C

Signifi

cant3 C

Signifi

cant3 C

Signifi

cant

Construction cost riskIs the project likely to be subject to cost

overruns FIN 5 E Low 5 E Low 5 E Low 5 E Low 5 E Low 4 C

Mode

rate4 C

Mode

rate3 C

Signifi

cant4 C

Mode

rate3 C

Signifi

cant3 C

Signifi

cant2 C

Signifi

cant2 C

Signifi

cant2 C

Signifi

cant2 C

Signifi

cant

Operation risk

Risk relating to the operational

requirements to implement and control the

option within operational requirements

DEL 2 BSignifi

cant5 D Low 3 B

Signifi

cant4 D Low 3 B

Signifi

cant4 D Low 4 D Low 4 D Low 4 D Low 4 D Low 4 D Low 4 C

Mode

rate4 C

Mode

rate4 C

Mode

rate4 C

Mode

rate

Option 5b- lower

operating level in

Lake Mulwala by

500mm

Progress

Concept

Option 6b:

Euston Weir -

Lower the

minimum

operating level

of Euston Weir

by 1.5 m to 46.1

m AHD

Option 6c:

Euston Weir -

Raise the

minimum

operating level

of Euston Weir

by 0.5 m to 48.1

m AHD and

Lower the

minimum

Progress

Concept

Progress

Concept

Option 7c: 11 GL

Storage at The

Drop on Mulwala

Canal

Progress

Concept

Option 7d: 16 GL

Storage at The

Drop on Mulwala

Canal

Progress Progress

Option 1- do

nothing

Option 2- alter

the 6-inch rule to

increase

operational

flexibility

Option 3a- policy

options to

manage within

the capacity of

the Barmah

Choke: Lake

Victoria transfers

Option 3b- policy

options to

manage within

the capacity of

the Barmah

Choke: Inter-

valley trade

Progress Progress

Concept

Progress

Concept

Progress

Concept

Option 3c- policy

options to

manage within

the capacity of

the Barmah

Choke: non-

asset solutions

Option 4-

increased

operational

flexibility in

existing assets:

Mildura Weir

Option 5a- lower

operating level in

Lake Mulwala by

100mm

Option 7b: 5 GL

Storage at The

Drop on Mulwala

Canal

Progress

Concept

Option 6a:

Euston Weir -

Raise the

minimum

operating level

of Euston Weir

by 0.5 m to 48.1

m AHD

Option 7a: 1 GL

Storage at The

Drop on Mulwala

Canal

Progress

Concept

Progress

Concept

MAXIMUM RISK SignificantSignificant Moderate Significant Moderate Significant Significant Significant High Significant Significant Significant Significant Significant

Progress

Concept

Significant



Figure 5-4 (continued) Classification of risk types for each option.

Project Risks

Risk Issue Description TypeC L Risk C L Risk C L Risk C L Risk C L Risk C L Risk C L Risk C L Risk C L Risk C L Risk C L Risk C L Risk C L Risk C L Risk C L Risk


The degree to which the plans call for

specialised personnel, methods, and

equipment will impact the risks inherent in

the project

DEL 4 D Low 2 BSignifi

cant2 B

Signifi

cant3 B

Signifi

cant3 C

Signifi

cant3 C

Signifi

cant3 C

Signifi

cant3 C

Signifi

cant3 C

Signifi

cant3 C

Signifi

cant3 C

Signifi

cant4 D Low 3 C

Signifi

cant3 C

Signifi

cant4 D Low


Risk the project will be subject to significant

approvals process e.g., EIS or Public

Inquiry from EPBC Act

REG 4 CMode

rate2 A High 2 A High 2 A High 4 C

Mode

rate4 C

Mode

rate4 C

Mode

rate4 C

Mode

rate3 C

Signifi

cant2 B

Signifi

cant2 A High 4 C

Mode

rate4 C

Mode

rate3 C

Signifi

cant3 C

Signifi

cant

Stakeholders and community

Risk the project is subject to significant

stakeholder, community or political

opposition

STK 4 D Low 2 BSignifi

cant2 B

Signifi

cant2 B

Signifi

cant4 C

Mode

rate4 C

Mode

rate4 C

Mode

rate4 C

Mode

rate4 C

Mode

rate2 B

Signifi

cant2 B

Signifi

cant4 C

Mode

rate4 C

Mode

rate4 C

Mode

rate2 B

Signifi

cant


Risk that changes to irrigation demand and

supply conditions mean the infrastructure is

being used significantly less than designed

for, and potentially obsolete

FIN 4 D Low 2 DSignifi

cant2 D

Signifi

cant2 D

Signifi

cant3 D

Mode

rate3 D

Mode

rate3 D

Mode

rate3 D

Mode

rate3 D

Mode

rate2 D

Signifi

cant2 D

Signifi

cant4 D Low 3 D

Mode

rate3 D

Mode

rate5 D Low

Environmental riskIs project construction likely to cause

unacceptable environmental damageENV 4 C

Mode

rate2 B

Signifi

cant2 B

Signifi

cant2 B

Signifi

cant3 C

Signifi

cant3 C

Signifi

cant3 C

Signifi

cant3 C

Signifi

cant3 C

Signifi

cant2 B

Signifi

cant2 B

Signifi

cant4 C

Mode

rate3 C

Signifi

cant3 C

Signifi

cant2 C

Signifi

cant

Construction cost riskIs the project likely to be subject to cost

overruns FIN 4 D Low 3 C

Signifi

cant2 C

Signifi

cant2 C

Signifi

cant3 C

Signifi

cant3 C

Signifi

cant3 C

Signifi

cant3 C

Signifi

cant2 C

Signifi

cant2 C

Signifi

cant1 C High 4 C

Mode

rate3 C

Signifi

cant2 C

Signifi

cant4 C

Mode

rate

Operation risk

Risk relating to the operational

requirements to implement and control the

option within operational requirements

DEL 4 CMode

rate3 C

Signifi

cant3 C

Signifi

cant3 C

Signifi

cant4 C

Mode

rate4 C

Mode

rate4 C

Mode

rate4 C

Mode

rate4 C

Mode

rate4 B

Signifi

cant4 B

Signifi

cant4 C

Mode

rate4 C

Mode

rate4 C

Mode

rate4 D Low

Progress

Concept

Option 11-

increase escape

capacity to the

Wakool River

Progress

Concept

Option 12a- 800

ML/d increased

escape capacity

to Edward River

Progress

Concept

Option 13-

Increased

escape capacity

to Broken Creek

Progress

Concept

Option 12b-

1,500 ML/d

increased escape

capacity to

Edward River

Progress

Concept

Option 12c- 2,000

ML/d increased

escape capacity

to Edward River

Progress

Concept

Option 14-

Barmah bypass

channel

Parked

Option 15-

Murray-Goulburn

Interconnector

Channel

Option 9-

Bullatale Creek

bypass

Parked

Option 10a:

Victorian Forest

Channels

(Kynmer Creek

Route)

Progress

Concept

Option 8-

construction of a

mid-river storage

On Hold

MAXIMUM RISK High High High Significant Significant Significant SignificantModerate

Option 16c: 1,000

ML/day Pericoota

Escape

Progress

Concept

Significant

Option 17-

Combined weir

option

Progress

Concept

Significant

Option 16a- 200

ML/day Pericoota

Escape

Progress

Concept

Moderate

Option 16b: 500

ML/day Pericoota

Escape

Progress

Concept

SignificantSignificant Significant High

Option 10b:

Victorian Forest

Channels (Gulf

Creek Route)

Progress

Concept



Technical feasibility risk

All options are considered technically feasible in so far as only current technologies are

required. There are no high risk options with respect to technical feasibility.

The significant risk options are related to major construction projects which are more at risk of

encountering technical feasibility constraints. This relates particularly to projects involving

construction of new, large-scale channels (Options 9, 10, 14, and 15).

Options to increase existing escape capacities (Options 11, 12, 13 and 16) have an overall

lower consequence and likelihood for technical feasibility; however they still remain a

significant risk. Option 3a is rated significant because of the difficulty of managing the

competing priorities of Lake Victoria.

Options assessed as moderate are generally limited to small-scale construction works, while

low risk options relate mainly to operational changes. Option 3b is rated moderate risk largely

due to the challenge of getting the rules changes right. A low risk for Option 4 is only

appropriate if the Mildura Weir is upgraded. Increasing operational flexibility at Mildura Weir

using the existing structure is likely to have a significant risk.

Option 8 is considered as low risk because the infrastructure for this option is largely built

already, and the option is more about developing operating rules.



Table 5-2: Risk associated with technical feasibility.

Options in category

Low

Option 1- do nothing


Option 5a- lower operating level in Lake Mulwala by 0.1 m

Option 5b- lower operating level in Lake Mulwala by 0.5 m

Option 6a- Euston weir: raise the minimum operating level by 0.5 m

Option 6b- Euston weir: lower the minimum operating level by 1.5 m

Option 6c- Euston weir: raise the minimum operating level by 0.5 m and lower

the minimum operating level by 1.5 m


Option 16a – 200 ML/day Perricoota Escape

Option 17 – combined weir manipulation

Moderate


Option 3b- policy options to manage within the capacity of the Barmah Choke:

Inter-valley trade

Option 3c- policy options to manage within the capacity of the Barmah Choke:

non-asset solutions

Significant

Option 3a- policy options to manage within the capacity of the Barmah Choke:

Lake Victoria transfers

Option 7a- 1 GL storage at “The Drop” on Mulwala Canal

Option 7b- 5 GL storage at “The Drop” on Mulwala Canal

Option 7c- 11 GL storage at “The Drop” on Mulwala Canal

Option 7d- 16 GL storage at “The Drop” on Mulwala Canal

Option 9- Bullatale Creek bypass

Option 10- Victorian forest channels

Option 11- increased escape capacity to Wakool River

Option 12a- increased escape capacity to Edward River (800 ML/day)

Option 12b- increased escape capacity to Edward River (1,500 ML/day)

Option 12c- increased escape capacity to Edward River (2,000 ML/day)

Option 13- increased escape capacity to Broken Creek

Option 14- Barmah bypass channel

Option 15- Murray-Goulburn Interconnector Channel

Option 16b – 500 ML/day Perricoota Escape

Option 16c – 1,000 ML/day Perricoota Escape

High



Regulatory conditions risk

Regulatory conditions risks relate to the requirement that the options will need to undergo

significant policy or regulatory approvals before proceeding. While meeting regulatory

approval processes is a normal part of project planning, and not a risk in and of itself, this risk

item is used to identify which options will require more rigorous approval processes than

others.

Options 9, 10 and 15 are grouped as having high risk because they may have high potential

environmental impacts that trigger the need for extensive reviews and environmental impact

assessments. Given the proximity to National Parks or sensitive environmental areas for

Options 9 and 10, this means the regulatory requirements are „almost certain‟. This makes

these options high risk.

A large number of options are classed as significant as they are judged to have a „possible‟ or

higher likelihood of significant approvals process requiring Ministerial approval. The risk to

Option 6 (enlarged storage capacity in Euston Weir) is rated as high risk because of the

possible impact to the upstream wetlands. Moderately rated options are those that may only

require minimal approvals, while low risk options are those that could be implemented without

regulatory approval.



Table 5-3: Risk associated with regulatory conditions.

Options in category

Low





Moderate


Inter-valley trade








Significant

Option 3c - policy options to manage within the capacity of the Barmah Choke:

non-asset solutions


Option 5a - lower operating level in Lake Mulwala by 0.1 m

Option 5b - lower operating level in Lake Mulwala by 0.5 m













High

Option 9 - Bullatale Creek bypass





Stakeholder and community risk

The only high risk option from a stakeholder and community perspective is the lowering of

Lake Mulwala by 0.5 m (Option 5b). This option was judged to be „almost certain‟ to cause

„extensive community dissatisfaction‟ making this a high risk option from a stakeholder and

community perspective.

There are a number of significant risk options relating to stakeholders and the communities.

Primarily these are the options that will cause community concern because of the size of the

project and the areas likely to be impacted. Option 10a and 10b relate to a sensitive

environmental area (Barmah National Park) which is „likely‟ to cause community concern on

environmental grounds, as is the Murray-Goulburn Interconnector (Option 15), the Bullatale

Creek bypass (Option 9) and the Barmah bypass (Option 14). The options which will involve

modifications for weirs (Mildura, Euston and Mulwala- Options 4, 5 and 6) are likely to create

significant risks due to the recreational/irrigator impacts that may be caused. Option 1 is rated

a significant risk as communities want to see action on shortfalls and freeing of restrictions on

trade. Option 3c is rated significant as some of the non-asset solutions involve changes to

entitlements which has the potential to cause concern.

Moderate risk projects have the potential to cause regional concern; however the likelihood is

at the low end of the scale. Low risk options largely relate to those which are assessed as

having very little noticeable impact on the community and are therefore unlikely to cause

community or political opposition.



Table 5-4: Risk associated with stakeholder and community.

Options in category

Low





Moderate


Inter-valley trade













Significant



non-asset solutions












High Option 5b- lower operating level in Lake Mulwala by 0.5 m



Demand and supply risk

Demand/supply risk occurs because of the potential for future changes in the irrigation

industry that may result in some of these assets not being used to their full potential and

possibly becoming obsolete. Given the amount of planning which would occur before the

implementation of any of these options, the likelihood of obsolescence is considered „unlikely‟

for all options.

The risk level is correlated with the asset cost, regulatory requirements, community opposition

and environmental consequences. The greater the effort to get the options implemented (in

terms of political capital expended, environmental degradation, and cost) the higher the

consequence of any obsolescence.

There has also been consideration of whether the options is just to relieve issues associated

with the Barmah Choke or could be useful for other purposes. This relates particularly to the

storage at „The Drop‟ on Mulwala Canal (Option 7) and the escape options (Option 11, 12 and

13) which may provide some operational benefits to Murray Irrigation Limited.



Table 5-5: Demand and supply risk.

Options in category

Low






Inter-valley trade


non-asset solutions











Moderate








Significant









High



Environmental risk

The environmental risk relates to the potential for unacceptable environmental damage. The

options were assessed based on their proximity to high value and sensitive environmental

assets and the likelihood of damage occurring. Options 9, 10, and 14 would pass through

sensitive environmental areas leading to the assessed high risk. The physical length of the

Option 15 means it is likely to pass through sensitive environmental areas. Moderate risk

options relate to options with a much smaller footprint in less sensitive areas while low

environmental risks are associated with non-asset based options.

Option 1 is considered a significant risk because in the absence of action, the management of

the Barmah Choke will result in continual decline in ecosystem values of the Barmah-Millewa

Forest.



Table 5-6: Environmental risk.

Options in category

Low




Inter-valley trade


non-asset solutions

Moderate






Significant























High



Construction cost risk

Construction cost risk relates to the risk of cost overruns. The higher risks are associated with

the larger and more complex options which have a significant construction cost. Option 15 is

assessed as high risk as while the likelihood of overrun is only „possible‟, the high capital cost,

means it sits in the highest consequence category. These risks may be reduced as construction

projects move from concepts to detailed design.



Table 5-7: Construction cost risk.

Options in category

Low






Inter-valley trade


non-asset solutions


Moderate






Significant



















High Option 15- Murray-Goulburn Interconnector Channel



Operation risk

The operation risk is assigned based on the operational difficulty of implementing the various

options. A significant risk is assigned to the „do nothing‟ option (Option 1) because

continuation of the current operations is likely to continue to create difficulties in meeting the

competing demands for consumptive and environmental water users. Option 3c will be

complicated to implement. The types of non-asset solutions suggested require a high level of

planning and agreement both with irrigators and between State governments. Further, there is

also the likelihood of unforeseen consequences.

Option 3a has a significant operation risk because of inherent optional difficulties associated

with deciding on the timing and volume of any transfers. This option carries the risk of causing

undesirable flooding of the Barmah Forest, loss of water in Lake Victoria through high

evaporation losses, the risk that the water may not actually be needed because of unanticipated

inflows from the Darling River, the management of any internal spills, and the need to abide

by the Lake Victoria Operating Strategy.

Those options assessed as having low risk are where operating rules must be developed but are

not anticipated being complicated or difficult to negotiate. Low risk options require only minor

changes to current operations.



Table 5-8: Operation risk.

Options in category

Low



Inter-valley trade









Moderate














Significant





non-asset solutions





High



5.4. Option key risk summary and mitigation

Table 5-9: Key risks for options and mitigation.

Option Key Risks Comment and Mitigation

Option 1- Do nothing Environmental risk (significant)

Stakeholder and community (significant)

Operation risk (significant)

The risks are mitigated by planning and assessing options to reduce unseasonal flooding and irrigator shortfalls. The Barmah Choke Study also mitigates community concern by undertaking a study of Barmah Choke options.

Option 2- Alter the 6-inch rule

Monitoring of bank erosion rates as recommended in Earth Tech (2008)

Option 3a- Policy options- Lake Victoria transfers

Technical feasibility (significant)

Operation risk significant)

This can be managed by consultation with operational staff and modelling to develop decision support rules that identify operating conditions where there are clear expected benefits from Lake Victoria transfers.

Option 3b- Policy options- inter-valley trade

Key risk is determining whether the IVT water is available when needed. There is no guarantee that IVT will occur in any particular year and will depend on the relative allocation percentages between regions.

Option 3c- Policy options- non-asset solutions

Regulatory risk (significant)


Operations risk (significant)

These risks can only be mitigated by a commitment to develop policies along with the agreements which would be required to ensure the option is workable.

Option 4- Increased flexibility- Mildura Weir



Environmental risk (significant)

Detailed communications and consultation program.

Option 5a- lower

operating level in Lake

Mulwala by 0.1 m







Option 5b- lower

operating level in Lake

Mulwala by 0.5 m


Construction cost risk (significant)


Stakeholder and community (high)

Option 6a- Euston weir:

raise the minimum

operating level by

0.5 m

Regulatory conditions (significant)



This project would require standard project planning and consultation processes.

Option 6b- Euston weir:

lower the minimum

operating level by

1.5 m




Construction cost (significant)


Option 6c- Euston weir:

raise the minimum

operating level by

0.5 m and lower the

minimum operating

level by 1.5 m




Construction cost (significant)


Option 7a- 11 GL

storage at “The Drop”

on Mulwala Canal



Demand/Supply risk (significant)



Further technical investigations would be required.




Option 7b- 16 GL

storage at “The Drop”

on Mulwala Canal



Demand/Supply risk (significant)



Further technical investigations would be required.

Option 8- Construction of a mid-river storage

No specific risk mitigation strategies required.

Option 9- Bullatale Creek

Technical Feasibility (significant)

As with any major capital spend, this project would need to undergo a detailed planning, consultation and approvals process. During this process, it may be possible mitigate the risks. Regulatory conditions

(high)


Demand \ supply risk (significant)




Option 10- Victorian

forest channels (both

routes)


As with any major capital spend, this project would need to undergo a detailed planning, consultation and approvals process. During this process it may be possible to mitigate the risks. Regulatory conditions

(high)









Option 11- Increased diversions through Wakool system




While no high risks, this option does not have any low risk items either. Mitigation is likely to be possible through normal planning processes.

Option 12a- Increased escape capacity to Edward River (800 ML/day)




As for Option 11

Option 12b- Increased

escape capacity to

Edward River

(1,500 ML/day)




As for Option 11

Option 12c- Increased

escape capacity to

Edward River

(2,000 ML/day)




As for Option 11





Construction cost risk can be mitigated by further investigative work to gain a better understanding of the requirements.









As with any major capital spend, this option would need to undergo a detailed planning, consultation and approvals process. During this process it may be possible to mitigate the risks.




Option 15- Murray Goulburn interconnector


As for Option 14

Regulatory conditions (high)




Construction cost risk (high)


Option 16a –

200 ML/day Perricoota

Escape

No specific risk mitigation strategies required.

Option 16b –

500 ML/day Perricoota

Escape





Option 16c –

1,000 ML/day

Perricoota Escape






Option 17 – Combined

weir manipulation Regulatory conditions (significant)



This option would require standard project planning and consultation processes.



6. Option modelling

6.1. Summary of modelling methods

Each option identified as suitable to “progress” for individual modelling and assessment has

been modelled in MSM-Bigmod as appropriate. MSM-Bigmod is a complex flow and salinity

modelling suite developed and maintained by MDBA, which has been used extensively to

simulate current and potential future system conditions in the River Murray. MSM-Bigmod is

used to inform the policy and decision making process.

All modelling was undertaken based on the pre-TLM reference run model (see description for

Option 1). This reference run represents pre-TLM operating conditions and historical climate

conditions. In the next phase of the Barmah Choke Study, other reference runs may be used as

part of a broader sensitivity analysis.

A very brief summary of the modelling method for each option is provided in Table 6-1. More

detailed, technical, descriptions of the modelling methods for each option are provided in

Appendix A. Modelling methods are not presented for parked and currently operational

options.

Some options (four) have been assessed by processing MSM-Bigmod inputs and outputs in a

spreadsheet to calculate indicators to evaluate the options rather than by direct processing of

MSM-Bigmod outputs.

Table 6-1: Summary of modelling methods for each option.

Option Modelling method

Option 1- do nothing MSM-Bigmod pre-TLM reference run model (user ID 1004TLM, run number 20506, supplied April 2010)


MSM-Bigmod modelling






Not a modelling option


Spreadsheet based modelling approach, calculated shortfall volume adjusted by the volume of active storage available in Mildura Weir.

Option 5- lower operating level in Lake Mulwala MSM-Bigmod modelling

Option 6- enlarged storage capacity in Euston Weir Spreadsheet based modelling approach, calculated shortfall volume adjusted by the volume of active storage available in Euston Weir.



Option Modelling method

Option 7- storage at “The Drop” on Mulwala Canal Spreadsheet based modelling approach, calculated unseasonal flood volume adjusted by the available capacity in The Drop storage (within inlet and outlet capacity constraints)

Option 10- Victorian forest channels MSM-Bigmod modelling







Option 15- Murray-Goulburn interconnector channel MSM-Bigmod modelling

Option 16- Perricoota Escape MSM-Bigmod modelling

Option 17- Combined weir manipulation Spreadsheet based modelling approach, calculated shortfall volume adjusted by the net volume of active storage available in the combined weirs.

6.2. Evaluation of option effectiveness

As discussed in Section 2.2, the main indicators that have been used to evaluate the potential

effectiveness of each option are the option‟s ability to address the issues associated with the

limited capacity of the Barmah Choke. Specifically, the impact of the option on the number of

years with unseasonal flooding of the Barmah-Millewa Forest and the number of years with

shortfalls or rationing of diversions has been considered.

The impact of the option on the beneficial influence of the Barmah Choke for flooding of the

Barmah-Millewa Forest and other areas or third parties have also been considered though the

use of project specific indicators developed as a part of the Investigation Phase (SKM, 2009)

(summarised in Table 2-1) and the suite of MDBA standard indicators (MBDA, 2010a) as

appropriate. See Appendix C for more detail on the indicators.



Table 6-2: Project specific indicators which may be used to assess option performance.

Objective Indicator

Conservation of water resources

Key allocation statistics for general security (NSW) and high and low reliability (Victoria) entitlements


Flooding regime of the Barmah-Millewa Forest percentage of years with small and large floods in the Barmah-

Millewa Forest

maximum duration (in years) with no flood

Frequency and magnitude of environmental flows in the River Murray System: Frequency of key flooding criteria at key locations

(Koondrook/Gunbower, Hattah Lakes, Chowilla/Lindsay;

Flows to South Australia Average flow to SA in excess of entitlement (GL/year)

% Years where flows to SA < 1850 GL/year

Significant impacts to other areas and third parties Maintain water levels in Lake Victoria and Menindee Lakes for

cultural heritage reasons

Avoid Werai Forest unseasonal flooding

Avoid undesirable exceedance of 25,000 ML/d downstream of Hume

Avoid undesirable exceedance of capacity of Edward and Gulpa offtakes

Maintain recreational water levels at Lake Mulwala and Euston Weir

For each option modelled, a summary of the modelling results relative to Option 1- „do

nothing‟ (the base case) has been prepared. This was based on the raw modelling and indicator

outputs, without interpretation of the impact.

6.3. Significance of the problem under the base case

The Investigation Phase of the Barmah Choke Study (SKM, 2009), found that the limited



through the Barmah-Millewa Forest.

This finding was based on the analysis of the significance of the problem under the base case.

Since the Investigation Phase, the base case used by the MDBA for modelling assessments has

changed. As such, the significance of the problem under the base case has been re-assessed.

The most significant impact of the change to the base case run is a significant reduction in the

volume of water entering the River Murray from the Goulburn River and a significant increase

in inflows from the Murrumbidgee River. These changes (along with the other changes to the



model) has led to an increase in the number of years with shortfalls. Appendix B presents a

detailed discussion of the changes and the impacts of the changes.

6.3.1. Shortfalls and rationing of diversions

Table 6-3 summarises the extent of the shortfall issue based on flow downstream of

Yarrawonga Weir under the base case (Option 1). These results show that shortfalls are a

problem under the base case, with shortfalls occurring in 24% of years. In 18% of years the

shortfalls are type I (peak demand) shortfalls, while in 6% of years the shortfalls are type II

(lower system storage) shortfalls.

This suggests that options focused on enabling rapid, short-term responses such as mid-river

storage options may be successful in significantly reducing the incidence of shortfall events;

however under such options a number of large, long-duration shortfalls events will remain if

additional measures are not taken.

Table 6-3: Shortfalls based on flow downstream of Yarrawonga Weir under Option 1.

Duration Average Magnitude (ML/day) Total by Duration

< 1,000 ML/day 1,001 –

1,500 ML/day

> 1,500 ML/day

1 – 5 days 7 3 2 12

6 – 10 days 3 4 1 8

11 – 15 days 0 1 1 2

> 15 days 1 0 5 6

Total by magnitude 11 8 9 28

Shortfalls which are expected to be manageable

Number (total) 14

Number (type I- peak demand) 12

Number (type II- lower system storage) 2

Average volume (GL) 2.7

Average duration (days) 3.6

Shortfalls which are expected to be challenging to manage

Number 7





Shortfalls which are expected to be more difficult to manage

Number 7





Total shortfalls Number (total) 28 (24% of years)

Number (type I- peak demand) 21 (18% of years)

Number (type II- lower system storage) 7 (6% of years)



6.3.2. Unseasonal flooding

Table 6-4 summarises the extent of the unseasonal flooding issue under the base case

(Option 1). Note some results for modelled natural conditions are also presented for

comparison. The results show that unseasonal flooding is a problem under the base case, with

moderate flooding occurring in 33 years over the model run (114 years) - three times more

frequently than under modelled natural conditions, and more severe flooding occurring in 29

years over the model run (114 years) - 5% more often than under modelled natural conditions.

The increase in the number of years of unseasonal flooding, particularly the increase in years

with moderate unseasonal flooding, may be contributing to changes in the ecological character

of the forest.

Table 6-4: Unseasonal flooding of the Barmah-Millewa Forest under Option 1 (some results for modelled natural conditions are also presented for comparison).

Duration Flow (ML/day) Total by

Duration 10,601 –

11,000

11,001 –

13,000

13,001 –

15,000

15,001 –

18,000

>18,000

0-2 days 1 13 4 0 0 18

3-7 days 0 7 9 14 12 42

>7 days 0 0 0 0 3 3

Total by Flow 1 20 13 14 15

Total years of unseasonal flooding (natural conditions- 38 years) 63

Total years of moderate unseasonal flooding (natural conditions- 11 years) 33

Total years of more severe unseasonal flooding (natural conditions- 24 years) 29

Proportion of wet years for each side of the forest (natural conditions- 31%) 40%

6.3.3. Other indicators and issues

A large number of other indicators have been prepared to allow potential option impacts on

other areas or third parties to be considered. The results of these indicators are presented in

Appendix D but are not discussed in this section as they are generally of a specific nature and

are unsuited to a general assessment of options.

6.4. Option evaluation

The main indicators that have been used to evaluate the potential effectiveness of each option

are the option‟s ability to address the issues associated with the limited capacity of the Barmah

Choke. Specifically, the impact of the option on the number of years with unseasonal flooding

of the Barmah-Millewa Forest and the number of years with shortfalls or rationing of

diversions has been considered.

The results of the indicator assessments for each option are presented in Appendix D and key

findings are discussed in this section by option.



Figure 6-1 summarises the impact of options on the significance of the problem for reducing

the incidence of shortfalls and unseasonal flooding. Figure 6-1 also indicates the relative cost

and highest risk category of each option. This plot allows rapid comparison and evaluation of

the options.

Figure 6-1: The position of the points on each axis shows the effectiveness of options for reducing the incidence of shortfalls and unseasonal flooding; with the size of the point indicating the cost; and the colour the highest risk category for the option.

The impact of each option on the beneficial influence of the Barmah Choke for flooding of the

Barmah-Millewa Forest and other areas or third parties have also been considered though the

use of project specific indicators developed as a part of the Investigation Phase (SKM, 2009)

and the suite of MDBA standard indicators (MBDA, 2010a).

For the purposes of discussing option effectiveness, the following categories have been

adopted:



low or limited effectiveness: the option leads to less than a 10% reduction in the number

of years with shortfall events or the number of years each side of the forest is wet

unseasonally (as appropriate)

moderate effectiveness: the option leads to a reduction in the number of years with

shortfall events or the number of years each side of the forest is wet unseasonally (as

appropriate) of between 10% and 40%

high effectiveness: the option leads to more than a 40% reduction in the number of years

with shortfall events or the number of years each side of the forest is wet unseasonally (as

appropriate)

Table 6-5: Key findings that can be gained from Figure 6-1.

Option effectiveness

Issue Option

Options which are highly effective

Unseasonal flooding

Option 5b- lower operating level in Lake Mulwala (0.5 m lowering

Option 7c and Option 7d- storage at The Drop on Mulwala Canal (11 GL and 16 GL storage)

Shortfalls Option 4a and Option 4b- increased operational flexibility in existing assets: Mildura Weir

Option 6b and Option 6c- enlarged storage capacity in Euston Weir

Option 17- combined weir manipulation

Option 15- Murray-Goulburn Interconnector

Both Nil

Options which are moderately effective

Unseasonal flooding


Option 5a- lower operating level in Lake Mulwala (0.1 m lowering

Option 7a and Option 7b- storage at The Drop on Mulwala Canal (11 GL and 16 GL storage)

Shortfalls Option 6a- enlarged storage capacity in Euston Weir

Option 3a- policy options to manage within the capacity of the Barmah Choke- Lake Victoria transfers

Option 3b- policy options to manage within the capacity of the Barmah Choke- inter-valley trade

Option 16c- Perricoota Escape (1,000 ML/day)

Both Option 12 (all sub-options)- increased escape capacity to the Edward River

Options which are of limited effectiveness



Option 16a and Option 16b- Perricoota Escape (200 and 500 ML/day)


Based on the key findings above, along with the assessment of option cost, risk category and

third party impact or issues, summaries have been prepared for each option and are presented

below. Note that third party impacts or issues are described as „nill impacts indicated by



modelling‟ where the modelling results (see Appendix D) indicated only a small (less than 2%)

change from Option 1.

Option 2 – alter the 6-inch rule to increase operational flexibility

Criteria Comment

Unseasonal Flooding Less than a 1% reduction in the number of years each side of the forest is wet unseasonally

Shortfalls Nil impact indicated by modelling

Third-party impacts or issues Nil impacts indicated by modelling

Risk category Moderate

Cost Minimal (operational change only)

Summary assessment Limited effectiveness

Option 3a – policy options to manage within the capacity of the Barmah Choke, Lake Victoria transfers

Criteria Comment

Unseasonal Flooding 7% reduction in the number of years each side of the forest is wet unseasonally

Shortfalls 21% reduction in number of years with shortfalls


Risk category Significant


Summary assessment Moderately effective at minimal cost

Option 3b – policy options to manage within the capacity of the Barmah Choke, inter-valley transfers

Criteria Comment


Shortfalls 21% reduction in the number of years with shortfalls


Risk category Moderate


Summary assessment Moderately effective at minimal cost



Option 4 – increased operational flexibility in existing assets- Mildura Weir

Criteria Comment

Unseasonal Flooding Nil impact

Shortfalls Option 4a- 43% reduction in the number of years with shortfalls

Option 4b- 54% reduction in the number of years with shortfalls

Third-party impacts or issues Nil indicated by modelling


Potential risk drawing down the weir may increase weir salinity (environment) and affect recreational use of the weir (stakeholders and community)

Cost $1.68 million (present value, base estimate)

Summary assessment Low cost and highly effective but similarly effective options are of lower cost

Other weir lowering options (Option 6 and Option 17) are similarly effective, but both expected to be of lower cost.

Based on the information currently available, Option 17 should be adopted in preference to Option 4 as it would be expected to be similarly (if not more) effective and would be expected to incur minimal cost (operational change only). If a single weir option is preferred, Option 6 should be adopted in preference to Option 4 as it would also be expected to be similarly effective and of lower cost.

Option 5 – lower operating level in Lake Mulwala

Criteria Comment

Unseasonal Flooding Option 5a- 19% reduction in the number of years each side of the forest is wet unseasonally

Option 5b - 54% reduction in the number of years each side of the forest is wet unseasonally

Shortfalls Nil indicated by modelling


Risk category High

Risk operating the weir at a lower level during irrigation season may affect recreational use of the weir (stakeholders and community)

Cost $3.4 million for Option 5a to $11.2 million for Option 5b (present value, base estimate)

Summary assessment Highly effective but high risk

This option (particularly the 0.5 m lowering option) is highly effective at reducing unseasonal flooding, however is expected to be a very high risk (stakeholder and community) associated with the negative impact on recreational use of the weir over the unseasonal flooding period, which coincides with the peak recreational period.



Option 6 – enlarged storage capacity at Euston Weir

Criteria Comment

Unseasonal Flooding Nil indicated by modelling

Shortfalls Option 6a- 32% reduction in the number of years with shortfalls

Option 6b– 50% reduction in the number of years with shortfalls

Option 6c- 54% reduction in the number of years with shortfalls



Potential risk drawing down the weir may affect recreational use of the weir (stakeholders and community)

Cost $0.83 million for Option 6a,$2.0 million for Option 6b, $2.3 million for Option 6c (present value, base estimate)

Summary assessment Low cost and highly effective, but a similarly effective option is of lower cost

Other weir lowering options (Option 4 and Option 17) are similarly effective, but Option 17 is expected to be of lower cost.

Based on the information currently available, Option 17 should be adopted in preference to Option 6 as it would be expected to be similarly effective and would be expected to incur minimal cost (operational change only). If a single weir option is preferred, Option 6 should be adopted in preference to Option 4 as it would also be expected to be similarly effective and of lower cost.

Option 7 – storage at “The Drop” on Mulwala Canal

Criteria Comment

Unseasonal Flooding Reduction in the number of years each side of the forest is wet unseasonally by:

Option 7a- 15%

Option 7b- 15%

Option 7c- 55%

Option 7d- 56%




Cost Option 7a- $6.2 million (present value, preliminary estimate)

Option 7b-$12.3 million (present value, preliminary estimate)

Option 7c- $70.9 million (present value, base estimate)

Option 7d- $87 million (present value, base estimate)

Summary assessment Smaller volume options are moderately effective but of high cost, larger volume options are highly effective but of higher cost



Option 10 – Victorian forest channel bypass

Criteria Comment




Risk category High

This option would require works (channel works and regulators) in a National Park which may not be appropriate

Cost $ 97.7 million (present value, base estimate)

Summary assessment Moderately effective but high risk and high cost

Option 11 – increased escape capacity to the Wakool River

Criteria Comment







Option 12 – increased escape capacity to the Edward River

Criteria Comment

Unseasonal Flooding Reduction in the number of years each side of the forest is wet unseasonally by:

Option 12a- 19%

Option 12b- 29%

Option 12c- 33%

Shortfalls 18% reduction in the number of years with shortfalls (all sub-options)



Cost Option 12a- $7.4 million (present value, base estimate)

Option 12b- $8.0 million (present value, preliminary estimate)

Option 12c- $9.8 million (present value, preliminary estimate)

Summary assessment Moderately effective



Option 13 – increased escape capacity to Broken Creek

Criteria Comment



Third-party impacts or issues Nil indicated by modelling (there is an increase in diversions through the Murray Valley irrigation system, however this water is returned to the River Murray System via Broken Creek, leading to no net change in water availability)




Option 15 – Murray-Goulburn interconnector channel

Criteria Comment



Third-party impacts or issues Nil indicated by modelling (there is an increase in diversions at Yarrawonga Weir, however this water is returned to the River Murray System via Goulburn River and Broken Creek, leading to no net change in water availability)

Risk category High

Risk that cost overruns could be very large (even a small proportional overrun could be large on such a big project) (construction cost risk) and significant regulatory approvals would be required (regulatory conditions)

Cost $394 million (present value, base estimate)

Summary assessment Highly effective but high risk and very high cost

Option 16 – Perricoota escape

Criteria Comment

Unseasonal Flooding Up to 9% reduction in the number of years each side of the forest is wet unseasonally

Shortfalls Up to 18% reduction in the number of years with shortfalls



Cost Option 16a- minimal (operational change only)

Option 16b- $9.8 million (present value, preliminary estimate)

Option 16c- $61.5 million (present value, preliminary estimate)





Criteria Comment

Unseasonal Flooding Nil indicated by modelling





Summary assessment Highly effective at minimal cost



7. Scenarios

The number and severity of shortfall events and unseasonal flooding events depends quite

heavily on level of development, water supply system configuration and capacity, and system

operating rules. It is important to assess how issues associated with the Barmah Choke may

change under different future operating regimes, such as different climate, different operating

rules and different level of demands.

Two different operating regimes were assessed as a part of the Barmah Choke Study prior to

the scenario modelling. The first was the base case in the Investigations Phase and the second

is the base case of this, the Individual Options Phase which assumed altered volume and

pattern of inflows to the system from the Goulburn, Murrumbidgee, Snowy and Darling

Rivers. The altered inflows were based on updated assumptions on how each of these river

systems would be managed.

To test the robustness of options under other alternative possible future conditions a sub-set of

options have been modelled under three alternative reference run scenarios (MDBA, 2010):

1) The post-TLM reference run scenario (reference run ID 20083), which represents post-

TLM operating conditions and historical climate conditions

2) The dry climate change to 2030 reference run scenario (reference run ID 20122), which

represents pre-TLM operating conditions and dry climate change to 2030 conditions

3) The post-TLM and dry climate change to 2030 reference run scenario (reference run ID

20075), which represents post-TLM operating conditions and dry climate change to 2030

conditions

These scenarios show that under the dry climate change to 2030 scenario, the number of

shortfalls increases slightly. There is a noticeable change in the distribution of shortfalls

between peak demand (type I) shortfalls and lower system storage (type II) shortfalls. The

instances and severity of lower system storage (type II) shortfalls decrease while the number

and severity of peak demand (type I) shortfalls increase. Under this scenario the number of

unseasonal flooding events decreases by approximately one third.

The post-TLM scenario does not change the total number of shortfall events significantly (27

compared to 28 in the base case). However, the severity of the shortfalls increases, with 14

shortfalls which are expected to be difficult to manage compared to 7 in the base case. This is

due mainly to the changes in tributary inflow due to TLM. In particular, the changes in flow in

the Goulburn and Murrumbidgee Rivers during summer result in large changes to timing and

magnitude of shortfall events. The TLM scenario increases the number of unseasonal flooding

events which is mainly due to some flow events being triggered that persist into January.



The combined post-TLM and dry climate change to 2030 conditions scenario results in a small

reduction in the number of total shortfall events but also an increase in peak demand shortfalls

and a decrease in lower system storage shortfalls. Under this scenario, the number of years

with unseasonal flooding events decreases from the base case (63 reduced to 54).

Five options were selected for scenario modelling based on their effectiveness (in terms of

shortfalls, undesirable flooding or both) and to represent different types of options. The options

included:

Option 1 – do nothing, representing the base case

Option 5b – lower operating level in Lake Mulwala (0.5 m lowering of normal operating

level over the unseasonal flooding period), representing an upper system storage option

targeting unseasonal flooding

Option 6c – enlarged storage capacity in Euston Weir (0.5 m raising of normal operating

level and 1.5 m lowering of minimum operating level), representing a lower system

storage option targeting shortfalls

Option 12b – increased escape capacity to Edward River (increase the escape capacity to

3,400 ML/day which is 1,000 ML/day additional capacity), a bypass option targeting

unseasonal flooding with the potential to help manage shortfalls as well

Option 15 – Murray Goulburn Interconnector, a large new bypass option.

The scenario modelling results are summarised below for each of the option type groupings.

7.1. Upper system options targeting unseasonal flooding

These options can be grouped into those options which:

provide storage capacity upstream of the choke

provide bypass capacity around the choke

provide combination of storage capacity upstream and bypass capactiy.

The effectiveness of options depends on:

total active storage available

capacity constraints of the bypass route

capacity constraints of getting flow into or out of the storage.

Figure 7-1 presents the percentage of years each side of the forest is wet unseasonally for the

“do nothing” option and the three options simulated for the scenarios which impact on

unseasonal flooding. It shows that under the dry climate change to 2030 scenario, lowering the

target operating level in Lake Mulwala (Option 5b) is effective in terms of the reduction of

flooding in the forest under each scenario. The increased Edward Escape capacity (Option

12b) and Murray-Goulburn Interconnector (Option 15) are more variable in their effectiveness



under the different scenarios. In particular, Options 12b and 15 are less effective at reducing

unseasonal flooding under the 2030 dry climate change scenario than the Lake Mulwala option

(Option 5b). The Lake Mulwala option is more effective as it utilises an active volume with no

capacity constraints to how much flow can be stored on a particular day – rather it is limited by

the total size of the unseasonal flow event and not its peak rate. In comparison, the two bypass

options are constrained to a maximum daily rate that can be used to pass unseasonal flow

events.

Figure 7-1: Percentage of years each side of the forest is wet unseasonally for each scenario for each option modelled that impacts on unseasonal flooding

7.2. Lower system storage options targeting shortfalls

Storage options downstream of Barmah Choke are a very effective type of option to reduce

shortfalls under different scenarios. Modelling of the Euston Weir option (option 6c) under the

post-TLM and dry climate change to 2030 scenario showed that these type of options are

effective at reducing the Barmah Choke shortfall issues (ranging from 45% to 70%) under the

different scenarios.

Storage options are effective as they are not constrained to a daily capacity, rather they are

constrained by total volume of the shortfall event (for reasons similar to those discussed above

for options involving storage upstream of the choke to reduce unseasonal flooding). A

0%

5%

10%

15%

20%

25%

30%

35%

40%

45%

Option 1(Do Nothing)

Option 5b(Lake Mulwala 0.5m)

Option 12b(Edward Escape 1500ML)

Option 15(Interconnector)

Pe

rce

nta

ge o

f ye

ars

eac

h s

ide

of t

he

fo

rest

is

we

t un

seas

on

ally

(%)

Option

PreTLM 2030dry PostTLM PostTLM 2030dry



potential major benefit of these options are that if they provide enough storage to draw on for a

long enough period, IVT transfers may be able to be called on to supplement supply. A current

constraint with options to address shortfalls is that large volumes of water which may

potentially be available from IVT accounts in the Goulburn and Murrumbidgee systems are not

able to be drawn upon due to the long time lag involved in getting water from headworks

systems in each of the systems to the River Murray.

The interconnector option is constrained by the pattern of IVT from the Goulburn system that

is used to supply the River Murray (which is in exchange for the additional supply to the

Shepparton Irrigation area in the Goulburn system).

Figure 7-2: Percentage of years with shortfalls for each scenario for each option modelled that impacts on shortfalls

7.3. Summary of outcomes from scenario modelling

The frequency and severity of simulated shortfall events are dependent on a number of factors.

A major driver is tributary inflows over the summer period when shortfalls are most likely to

occur. Changes to irrigation demands (via changed allocations due to different inflows) also

impact the results but this impact appears to have less of an effect on shortfalls than the

volume and pattern of tributary flows downstream of Barmah Choke.

0%

5%

10%

15%

20%

25%

30%

Option 1(Do Nothing)

Option 6c(Euston Weir +0.5m & -1.5m)

Option 15(Interconnector)

Pe

rce

nta

ge o

f ye

ars

wit

h s

ho

rtfa

lls

(%)

Option

PreTLM 2030dry PostTLM PostTLM 2030dry



Options that involve drawing on storage downstream of the Choke have been shown to be very

effective in the scenarios modelled.

The extent of the unseasonal flooding is also dependent on inflows, with the dry climate

change to 2030 scenario dramatically reducing the number of unseasonal flood events, while

the post-TLM scenario increased them. Of the options modelled for the scenarios which

reduced unseasonal flooding, the most effective was the largest storage option (Mulwala 0.5m,

Option 5b) which had approximately 21 GL of active airspace. Under the scenarios this was

still the case.



8. Option package recommendations

Phase 4 of the Barmah Choke Study aims to build on the results of this, the Individual Options

Phase, to develop an integrated package of options for consideration by the MDBA and

stakeholders. Figure 6-1 in Section 6, which summarises the evaluation of individual options,

shows the potential for an integrated solution to better address Barmah Choke issues over any

single option. However, in most cases it will not be appropriate to just add the effectiveness of

options to estimate the improvement in condition if multiple options were implemented:

For some combinations of options the combined effectiveness is simply, at best, the

effectiveness of the larger option. For example, the Edward Escape (Option 12) and the

Wakool Escape (Option 11) both require capacity in the Mulwala Canal to bypass flow

around the Barmah Choke. There is unlikely to be sufficient capacity to run the large

versions of both options together so there is minimal value in implementing these options

at the same time.

There are likely to be decreasing marginal returns to multiple interventions. When options

are assessed separately, they both have the opportunity to claim the easy gains, the small

unseasonal floods and shortfalls. If implemented together, the amount of „low hanging

fruit‟ remains the same but will be claimed by multiple rather than one option, making

each option within the combination appear less effective.

Quantifying the effect of multiple options will require MSM-Bigmod modelling, which is the

purpose of Options Integration Phase of the Barmah Choke Study. However, based on the

experience of option modelling in the current phase (Phase 3), along with the risk and cost

analysis that has been undertaken, it is possible to make preliminary recommendations of

packages of options for consideration by the MDBA. The packages and the options within

each package have been chosen to meet a particular objective. Details on packages are

provided below. In summary these are:

1) options that can be ruled out and do not require further analysis

2) low investment options

3) options that can be implemented quickly

4) options to address unseasonal forest flooding

5) options to address shortfalls

6) options with the largest environmental benefits

7) options shared between NSW and Victoria

8) package of options that is likely to result in best performance

9) „the works‟ i.e. a combination of the most effective individual options



8.1. Options that can be ruled out

First, some options can be ruled out. These are the options which at best are „weakly

dominated‟ by other options. That is, there are many situations where other options are better

(more effective, less costly and less risky) and no situations where the weakly dominated

option is better. Some options can be ruled out because they are simply too costly, risky and

lack effectiveness (Table 8-1).

Table 8-1: Options that can be ruled out

Option No. Description

2 Alter the 6-inch rule to increase operational flexibility

9 Bullatale Creek bypass

10 Victorian forest channels

14 Barmah bypass channel

15 Murray-Goulburn interconnector channel

8.2. Low investment options

This package includes those options that have low cost but remain moderately effective. This

may be an attractive option if there is limited budget to address Barmah Forest issues.

Table 8-2: Low investment options


3a Policy options to manage within the capacity of the Barmah Choke- Lake Victoria transfers

3b Policy options to manage within the capacity of the Barmah Choke- inter-valley trade

5a Lower operating level of Lake Mulwala (0.1 m lowering)

17 Combined weir manipulation

16a Perricoota Escape (200 ML/d capacity)

8.3. Options that can be implemented quickly

This package includes those options that can be implemented quickly. They are low risk,

require limited structural works and limited changes to current operating arrangements. This

package may be appropriate if there is an imperative by the MDBA and the States to address

problems within about 18 months i.e. if the options were approved in one financial year they

could be implemented by the end of the following financial year.



Table 8-3: Options that can be implemented quickly



12a Increased escape capacity to the Edward River (800 ML/d additional capacity)

16a Perricoota Escape (200 ML/d capacity)


8.4. Options to address forest flooding

The most effective options to reduce unseasonal forest flooding are included in this package.

This package may be appropriate for consideration by the MDBA and other stakeholders if

forest flooding by itself, becomes the main issue. This package of options combines increased

storage upstream of the Choke and bypasses on both the Victorian and NSW sides of the

forest.

Table 8-4: Options to reduce unseasonal forest flooding


5b Lower operating level of Lake Mulwala (0.5 m lowering)

12c Increased escape capacity to the Edward River (2,000 ML/d additional capacity)

13 Increased escape capacity to Broken Creek

8.5. Options to address shortfalls

The most effective options to reduce shortfalls are included in this package. This is a

combination of bypasses, improved weir operations (downstream of the Barmah Choke) and

improved use of inter-valley trade.

Table 8-5: Options to reduce shortfalls



4b Increased operational flexibility in existing assets- Mildura Weir (2 m lowering)

6c Enlarged storage capacity in Euston Weir (+0.5 m, -1.5 m)


17 Combine weir manipulation (excluding Euston Weir and Mildura Weir as they will be implemented separately)

8.6. Options with the largest environmental benefit

Options with positive environmental benefits have been included in this package. For example,

Broken Creek bypass (Option 13) addresses shortfalls but is also likely to lead to an



improvement in water quality in Broken Creek. The Wakool River and Edward River bypasses

may allow improved watering of NSW riverine forests. In this package, options where poor

environmental outcomes represent a project risk are avoided. This may be an attractive

package of options if environmental benefits were sought and addressing Barmah-Millewa

Forest issues could be achieved as a secondary objective.

Table 8-6: Options with largest environmental benefits


11 Increased escape capacity to the Wakool River (500 ML/d additional capacity)



8.7. Options shared between New South Wales and Victoria

This package of options is likely to be highly effective and shares required works, approvals

and expenditure between NSW and Victoria. This may be an appropriate package if

implementation budgets must be negotiated between the States and the Commonwealth.

Table 8-7: Package where options are shared between NSW and Victoria


5a Lower operating level of Lake Mulwala (0.1 m lowering)




8.8. Best performance

The preliminary assessment indicates that this package of options is likely to have the best

performance in addressing both shortfalls and unseasonal flooding for reasonable cost (there

are however significant risks that would need to be addressed).

Table 8-8: Package of best performing options


5b Lower operating level of Lake Mulwala (0.5 m lowering)





8.9. The works

This package combines those options that are best at addressing shortfalls and those options

that address unseasonal flooding. Although probably not feasible or appropriate to implement

because of the issue of decreasing marginal returns, this package would provide „an upper

bound‟ (in contrast to a baseline) that can be used to compare the effectiveness of other option

packages. This includes all the options in Table 8-4 and Table 8-5.

8.10. Other considerations

8.10.1. Avoiding high risk Option 5b

There is only one „high‟ risk option included in these packages and that is to Option 5b –

reduce operating level at Mulwala by 0.5 m. If this option is considered too risky then Option 7

(storage at the drop) could be included instead- for each package that currently includes Option

5b, substitute Option 7.

8.10.2. Considering Option 3c – non-asset solutions

Of the remaining options, Option 3c, the non-asset solution, is a special case. For this option

further analysis is required to explore ways to reduce the simultaneous demand for irrigation

and environmental water during times when shortfall events are likely. To compare the

management of environmental entitlements, further modelling could be undertaken to

understand the impacts of the CEWH water holdings. The key requirement would be to

develop rules for the use of environmental water and then include these rules in modelling.

Development of appropriate rules is likely to require discussion between the CEWH and the

MDBA. Once these rules were agreed, this option should first be modelled by itself and then in

combination with other options depending on preliminary results.



9. Conclusions

The aim of the Barmah Choke Study is to develop an understanding of current and potential

future water supply and environmental risks associated with the Barmah Choke and other mid-

river operational issues. The intent is to identify a preferred option, or package of integrated

options, for reducing the impact of operational and policy challenges while recognising that

the Barmah Choke performs an important role in flooding the Barmah-Millewa Forest.

This, the “Individual Options Phase” of the Barmah Choke Study has built upon the outputs of

the previous phases. It has described, modelled and assessed individually a range of

operational, policy and structural river management options shortlisted in the previous

“Investigations Phase”. This has led to a refined shortlist of options and recommendations on

packages of options for integrated modelling and assessment in the next phase of the Barmah

Choke Study.

Options

Options to reduce or eliminate the issues associated with the limited capacity of the Barmah

Choke have been grouped into a number of broad categories:

policy options

upper system storage options targeting unseasonal flooding

lower system storage options targeting shortfalls

bypass capacity options.

Option evaluation

The approach adopted to evaluate options provides decision makers with the pertinent

information required to support and inform decision making. The process involves

consideration of three items for each option:

1) modelling outputs and indicators (and their interpretation) as a measure of effectiveness

2) cost estimates

3) risk assessment

These were combined to define each option such that a recommendation could be made about

their suitability for further assessment. Using this approach, favourable options are those

options which combine effectiveness, acceptable cost and acceptable risk.

Summary of key findings

Figure 6-1, in Section 6 provides a graphical summary of the impact of options on the

significance of the problem for reducing the incidence of shortfalls and unseasonal flooding. It

also shows the relative cost and highest risk category of each option. In addition to the plot, a

summary assessment for each option is provided in Table 9-1.



Table 9-1: Option summary assessments- key finding, green highlighting indicates options of particular potential.


Option 1- do nothing The base case








Use of environmental entitlements has potential to be an efficient and effective way of reducing the impacts of shortfalls as well as reducing total shortfalls altogether. The way in which environmental entitlement holders utilise their entitlement could have a significant impact on management of the Barmah Choke


a) minimum operating level lowered by 1 m

b) minimum operating level lowered by 2 m

Low cost and highly effective but similarly effective options are of lower cost

Option 5- lower typical operating level in Lake Mulwala

a) by 0.1 m

b) by 0.5 m

Option 5b is highly effective but high risk and moderate cost. Option 5a, is less effective than option 5b, but is lower risk and low cost


a) maximum operating level raised by 0.5 m

b) minimum operating level lowered by 1.5 m

c) maximum operating level raised by 0.5 m and minimum operating level lowered by 1.5 m

Low cost and highly effective. Other weir options (option 4 and option 17) are similarly effective


a) storage capacity of 1 GL

b) storage capacity of 5 GL

c) storage capacity of 11 GL

d) storage capacity of 16 GL

Smaller volume options are moderately effective but of moderate cost, larger volume options are highly effective but of high cost

Option 8- construction of a mid-river storage On-hold: no assessment made because mid-river storage is already operational

Option 9- Bullatale Creek bypass Not assessed: would require significant works in a National Park which means this option is not likely to be appropriate

Option 10- Victorian forest channels Moderately effective but high risk and high cost


Limited effectiveness, moderate cost


a) additional 800 ML/day capacity

b) additional 1,500 ML/day capacity


Moderately effective, moderate cost






Option 14- Barmah bypass channel Not assessed: a large, high cost channel in close proximity to the Barmah Forest National Park. A high risk, high cost option

Option 15- Murray-Goulburn interconnector channel Highly effective but high risk and high cost

Option 16- Perricoota Escape

a) use existing additional capacity (200 ML/day)

b) additional 500 ML/day capacity


Limited effectiveness (option 16a – low cost, option 16b – moderate cost, option 16c – high cost)

Option 17- Combined weir manipulation Highly effective low cost

Option package recommendations

The Options Integration Phase of the Barmah Choke Study should build on the results of this

phase, to develop an integrated package of options for consideration by the MDBA and other

stakeholders. Clearly an integrated solution that combines a set of options is likely to better

address Barmah Choke issues than any single option.

Quantifying the effect of multiple options will require MSM-Bigmod modelling. However,

based on the information gathered as a part of this phase (Phase 3), preliminary

recommendations of packages of options have been prepared for consideration by the MDBA

and are summarised in Table 9-2.

Table 9-2: Option package recommendations.

Package Options

Options that can be ruled out Option 2- Alter the 6-inch rule to increase operational flexibility





Low investment options Option 3a- Policy options to manage within the capacity of the Barmah Choke- Lake Victoria transfers

Option 3b- Policy options to manage within the capacity of the Barmah Choke- inter-valley trade

Option 5a- Lower operating level of Lake Mulwala (0.1 m lowering)

Option 17- Combined weir manipulation

Option 16a- Perricoota Escape (200 ML/d capacity)

Options that can be implemented quickly

Option 3b- Policy options to manage within the capacity of the Barmah Choke- inter-valley trade

Option 12a- Increased escape capacity to the Edward River (800 ML/d additional capacity)

Option 16a- Perricoota Escape (200 ML/d capacity)




Package Options

Options to address forest flooding


Option 12c- Increased escape capacity to the Edward River (2,000 ML/d additional capacity)


Options to address shortfalls Option 3b- Policy options to manage within the capacity of the Barmah Choke- inter-valley trade

Option 4b- Increased operational flexibility in existing assets- Mildura Weir (2 m lowering)

Option 6c- Enlarged storage capacity in Euston Weir (+0.5 m, -1.5 m)


Option 17- Combine weir manipulation (excluding Euston Weir and Mildura Weir as they will be implemented separately)

Options with the largest environmental benefit

Option 11- Increased escape capacity to the Wakool River (500 ML/d additional capacity)



Options shared between NSW and Victoria





Best performance Option 5b- Lower operating level of Lake Mulwala (0.5 m lowering)



The works Combination of packages: Options to address forest flooding plus options to address shortfalls



10. References

Bennett, M., undated, The Legalities: Do Covenants Really Work? Environmental Defender‟s

Office (WA), available at: http://www.edowa.org.au/archives/15_Covenant.pdf

Bren, L.J., 2005, The changing hydrology of the Barmah-Millewa Forest and its effects on

vegetation, Proceedings of the Royal Society of Victoria 117: 61-76.

Bren. L.J., O'Neill, I. and N.L. Gibbs, 1987, Flooding in Barmah Forest and its relation to

flow in the Murray-Edward River system. Aust. For. Res. 17, 127-44.

Earth Tech, 2007, The River Murray Six Inch Rule, unpublished report prepared for the

Murray-Darling Basin Commission.

Evans and Peck, 2008, Best Practice Cost Estimation for Publicly Funded Road and Rail

Construction, Report to Department of Infrastructure, Transport, Regional Development and

Local Government.

GHD, 2007, Investigation of the Potential to Recover Water by Construction of an En-route

Storage at “The Drop” on the Mulwala Canal, Feasibility Assessment, Final Report prepared

for The Living Murray – Project No W83, June 2007, unpublished report for the Murray

Catchment Management Authority.

G-MW, n.d., New $10 million Mid-Murray Storage Works to Begin Soon, archived news

release available from: http://www.lakemokoan.com.au/mid-

murraystorage/current_issues.htm#archive

G-MW, 2007a, Mid-Murray Storage Project, Fact Sheet 3: Project Overview, March 2007,

published by Goulburn-Murray Water, North Central Catchment Management Authority and

the (Victorian) Department of Sustainability and Environment, available from:

http://www.lakemokoan.com/cmocms/Publication/Docs/Project%20Overview.pdf

G-MW, 2007b, Mid-Murray Storage Project, Fact Sheet 7: Environmental, September 2007,

published by Goulburn-Murray Water, North Central Catchment Management Authority and

the (Victorian) Department of Sustainability and Environment, available from:

http://www.lakemokoan.com/cmocms/Publication/Docs/GMW%20Fact%20Sheet%206%20lo

res.pdf

G-MW and MDBA, 2008, Lake Mulwala Land and On-water Management Plan, 2008

Addendum, published by Goulburn-Murray Water, Shepparton, Victoria.

G-MW and MDBC, 2004, Lake Mulwala Land and On-water Management Plan, published by

Goulburn-Murray Water, Shepparton, Victoria.



Green, D., 2001, The Edward-Wakool System, River Regulation and Environmental Flows,

Department of Land and Water Conservation, Murray Region, Deniliquin, NSW.

Green, S.J., 1999, Drawdown and Riverbank stability, Master of Engineering Science Thesis,

Department of Civil and Environmental Engineering, University of Melbourne.

Hajkowitz, S, 2008, Rethinking the economist’s evaluation toolkit in light of sustainability

policy, Sustainability: Science, Practice & Policy, Spring 2008 Volume 4 Issue 1

Howitt, J. A., D. S. Baldwin, G. N. Rees and J. Williams, 2007, Modelling blackwater:

predicting water quality during flooding of lowland river forests. Ecological Modelling 203:

229-242.

Howitt, J. A., D. S. Baldwin, G. N. Rees and J. Williams, 2005, BLACKWATER MODEL – A

revised computer model to predict dissolved oxygen and dissolved carbon downstream of

Barmah-Millewa Forest following a flood. Report to the Murray-Darling Basin Commission.

139 pp.

MacDonald, H.H., Conner, J., and Morrison, M., 2004, Market-Based Instruments for

Managing Water Quality in New Zealand, final report of the New Zealand Ministry for the

Environment.

MDBA, 2010a, River Murray System Operations Review, Reference Run Report 2010, Version

1, January 2010, unpublished report (Trim Ref D09/19519).

MDBA, 2010b, MDBA Risk Management Guidelines

MDBA, 210c, River Murray System Annual Operating Plan (Public Summary), 2010-11 Water

Year 1 June 2010 – 31 May 2011, D10/28829, 10 October 2010.

MDBC, 2008, Barmah Choke Study, Fact Sheet 1: Project Background, Fact Sheet, February

2008, published on-line by the MDBC, available at:

http://thelivingmurray2.mdbc.gov.au/__data/page/1908/Barmah_Choke_FS1.pdf

MDBC, 2006, The Barmah-Millewa Forest Icon Site Environmental Management Plan, 2006-

2007, Technical report no. 30/2006.

MIL, 2007, Annual Report 2007, published by MIL, Deniliquin.

Murray-Darling Basin Ministerial Council, 2002, Lake Victoria Operating Strategy, published

by the Murray-Darling Basin Commission, Canberra.



Nation, R.M., and Ladson, A.R., 2008, Saving Water by Changing the Operation of Hume

Dam, paper presented to the Water Down Under 2008 Conference, Adelaide, 15–17 April,

2008.

National Water Commission, 2010, The impacts of water trade in the southern Murray-

Darling Basin, an economic, social and environmental assessment, paper currently under

review for publication as a Waterlines Report in 2010.

Productivity Commission, 2006, Rural Water Use and the Environment: The Role of Market

Mechanisms, research report, Melbourne.

Productivity Commission, 2010, Market Mechanisms for Recovering Water in the Murray-

Darling Basin, research report, Melbourne

River Murray Commission, 1980, River Murray Commission Review Report on River Murray-

Tocumwal to Echuca River Regulation and Associated Forest Management Problems, River

Murray Commission, Canberra, ACT, 2601.

River Murray Water, 2006, Backgrounder 3: Lake Hume – Overview of Operations. Murray-

Darling Basin Commission, available at: http://www.mdbc.gov.au/rmw/river murray

system/dartmouth reservoir/hume and dartmouth dams operations review/backgrounder 3: lake

hume – overview of operations.

Roberts, J. and Marson, F., 2000, Water regime of wetland and floodplain plants in the

Murray-Darling Basin: A source book of ecological knowledge. CSIRO Land and Water

Technical Report 30/00

Robertson, A.I., Bacon, P. and Heagney, G., 2001, The response of floodplain primary

production to flood frequency and timing. Journal of Applied Ecology 38:126-136.

SMEC, 2002, Review of Structures and Operation of Flow Regulating Infrastructure of the

River Murray System, Project E10, Environmental Flows and Water Quality Objectives for the

River Murray Project, Final Report, January 2002, unpublished report prepared for the

Murray-Darling Basin Commission.

SKM, 2009, Barmah Choke Study, Investigation Phase Report, Final 2, 24 July 2009, report

prepared for the Murray-Darling Basin Authority, published online at:

http://www.mdba.gov.au/services/publications/download?publicationid=48&key=1622

SKM, 2007, Barmah Choke Study, Project Plan, Final, 10 December 2007, unpublished report

prepared for the Murray-Darling Basin Commission.



SKM, 2006a, Assessment of Hydraulic Characteristics of Tuppal Creek and Bullatale Creek

Systems, Final Report, January 2006, unpublished report prepared for the (NSW) Department

of Natural Resources.

SKM, 2006b, Assessment of Victorian Demands in the River Murray and Future Supply

Options, Final (2) Report, January 2006, unpublished report to the (Victorian) Department of

Sustainability and Environment.

SKM, 2006c, Improved Management of Rainfall Rejections Upstream of the Barmah Choke,

Final Report, August 2006, unpublished report for (NSW) Department of Natural Resources.

SKM, 2006d, Assessment of current ecological condition and investigations for potential

outcomes resulting from proposed management changes of the Tuppal and Bullatale Creek

systems, Final Report, July 2006, unpublished report for (NSW) Department of Natural

Resources.

SKM, 2005b, Study of Impacts on River Users arising from Variations of the Euston Weir Pool

Level, Final (H), unpublished report prepared for the Murray-Darling Basin Commission.

SKM, 2005b, Lake Boga/Kerang Lakes options for mid-Murray Storage, unpublished report

prepared for the (Victorian) Department of Sustainability and Environment.

Water Technology, 2008, Barmah-Millewa Hydrodynamic Modelling: Model Re-calibration.

Goulburn-Broken Catchment Management Authority.

Water Technology, 2006, Barmah-Millewa Hydrodynamic Model: Additional Investigations.

Goulburn Broken Catchment Management Authority.

Water Technology, 2005, Barmah-Millewa Forest Hydrodynamic model. Goulburn Broken

Catchment Management Authority.



Glossary

Terminology Meaning

Allocation “The seasonal allocation represents the amount of water available to be delivered to customers in a regulated system in that season, expressed as a percentage of the system‟s total water entitlement” (G-MW, 2008)

Basin Plan The Basin Plan will be a strategic plan for the integrated and sustainable management of water resources in the Murray-Darling Basin, and is being prepared by the MDBA, as required by the Water Act 2007 (Cwlth) in consultation with Basin States and communities.

Benchmark “defines the dates between which a model run extends (e.g. 1891 to 2009) and can include any number of standard and non-standard reference runs and/or climatic models” (Reference Runs Report, 2010a)

Criteria Basis of the assessment method e.g. multi-criteria analysis. Broad attributes to consider and differentiate options and hence inform decision making (e.g. „environmental benefit)‟.

Effectiveness Effectiveness refers to how well a solution achieves its intended outcomes. For the Barmah Choke Study, this means how well options can reduce or mitigate the impacts of shortfalls or undesirable flooding.

Efficiency Efficiency can be defined in two ways – the first refers to delivering the project at least cost (cost-effective and fair and reasonable value for money). The second refers to whether an investment returns a net benefit. This is whether the costs outweigh the benefits (taking into account financial, social and environmental costs)? The latter definition is the appropriate meaning for the Barmah Choke Study. Efficiency can be measured in a number of ways but is often assessed through a cost-benefit analysis which is beyond the needs of this study. As such the likely costs and benefits are considered qualitatively and a judgement is made on the likely efficiency.

Indicator Expressed in modelling terms e.g. „Frequency of events >10,600 ML/day downstream of Yarrawonga Weir for >7 days during the undesirable flooding assessment period (1 January to 31 March)

Lower system storage shortfall (type II)

Lower system storage shortfalls are typically long in duration affecting the whole River Murray System downstream of the Barmah Choke (through to South Australia) caused by limited resources in Lake Victoria and the Menindee Lakes and insufficient channel capacity to implement bulk transfers to Lake Victoria (SKM, 2009).

Moderate undesirable flooding

Floods with a peak magnitude of greater than 11,000 ML/day but less than 15,000 ML/day are classified as moderate floods. These floods exceed the threshold at which significant impacts on vegetation communities would be expected to occur (11,000 ML/day) but are below the threshold where red gums would be impacted (15,000 ML/day). Floods of this magnitude can be restricted to one side of the forest through the manipulation of regulators.

More severe undesirable flooding

Floods with a peak magnitude of 15,000 ML/day or more are classified as more severe floods. These floods exceed the threshold at which red gums are impacted and will impact both sides of the forest.

Peak demand shortfall (type I)

Peak demand shortfalls are typically short duration events in the mid-reaches of the river between the Barmah Choke and Lake Victoria caused by insufficient channel capacity to meet peak irrigation demands (SKM, 2009).

Proportion of wet years for each side of the forest

Floods with a peak magnitude of less than 15,000 ML/day can be restricted to one side of the forest through the manipulation of regulators. As such, the proportion of wet years for each side of the forest is less than the total proportion of wet years.

The proportion of wet years for each side of the forest is equal to half the proportion of years with floods with a peak magnitude of less than 15,000 ML/day plus the proportion of years with floods of a peak magnitude of 15,000 ML/day or higher.



Terminology Meaning

Rainfall rejection Rainfall rejections occur when a combination of reduced irrigation demands (due to rain in the irrigation areas) and increases in inflows from unregulated tributaries lead to increased flows in the River Murray, causing river levels to rise and exceed the capacity of the Barmah Choke, flooding the Barmah-Millewa Forest (MDBC, 2008).

Reference Run “a set of modelling assumptions applied to a given benchmark period that defines how the parameters of the river (including which climatic mode we are using) are specifically configured in the model for that given run” e.g. „MDBSY 2030‟ (Reference Runs Report, 2010a)

Shortfall Each year in the River Murray System, an allocation is announced for both NSW and Victoria at the start of the irrigation season and progressively updated during the irrigation season. Irrigator and other demands are restricted based on the announced allocation. Shortfalls occur when the restricted demands cannot be supplied due to channel capacity constraints or a lack of resource storage in the lower system (SKM, 2009).


Shortfalls of either short duration or low magnitude (but not both) are classified as

„expected to be challenging to manage‟. This category reflects that as the volume or duration of a shortfall event increases it becomes more challenging for operators to manage or avoid and it is more likely that demands will be rationed or shortfalled.


Shortfalls of short duration and low magnitude are classified as „expected to be

manageable‟. This category reflects that there are a wide range of ad-hoc measures and responses that can be implemented by operators to manage or avoid short duration, low magnitude shortfalls.


Shortfalls of long duration and high magnitude are classified as „expected to be more

difficult to manage‟. This reflects that it is unlikely that such conditions could be managed or avoided through the use of ad-hoc measures and responses available to operators and it is very likely that demands will be rationed or shortfalled.

Sub-criteria Sub-components of criteria e.g. „Reduction in undesirable flooding of the Barmah-Millewa Forest‟.

Sub-options Variants of options that for example define the upper, mid and lower bounds of an option, or other instances / characteristics as agreed. Sub-options are defined in the Options Review Report (SKM, 2010).

System operating requirements

“Water released from storage but not recorded through the customer‟s outlets, examples include evaporation, leakage, seepage, meter error and unplanned spills. Sometimes called „losses‟” (G-MW, 2008)

The Living Murray The Living Murray program, established in 2002 aims to achieve a healthy working River Murray System through the recovery of water for the system and the operating of environmental works. The program‟s „first step‟ was implemented from 2004-2009 and recovered almost 500 GL of water for the environment.

Undesirable flooding Flows which exceed the capacity of the Barmah Choke lead to flooding of the Barmah-Millewa Forest. Flooding which occurs between the 15

th of December and

the 30th

of April can be detrimental to the health of the forest and is referred to as undesirable flooding (SKM, 2009).



Appendix A Detailed review of Option 3c

A.1 Option description

Assessing non-asset solutions is often a critical requirement of funding agencies when

assessing capital program bids. Should a business case be developed in the future for a capital

program for the Barmah Choke, it will need to consider non-asset solutions. Non-asset

solutions require important consideration as they can mean significant avoided costs,

especially where large capital investments are proposed.

This section provides an overview of potential non-asset solution that could be used to manage

the impacts of capacity constraints in the Barmah Choke and recommends whether they should

be investigated further based on their potential to deliver an efficient and effective solution.

The non-asset solutions assessed include:



Use of environmental entitlements, and

Incentive or congestion pricing measures.

It is important to note that the non-asset solutions considered (apart from environmental

entitlements) cannot reduce the incidence or magnitude of shortfalls and they are not expected

to have an impact on undesirable flooding of the Barmah-Millewa Forest. The primary purpose

is to provide a solution that enables river operators and the irrigation community manage the

impact of shortfalls effectively (and efficiently). By reducing the impact of both peak demand

(type I) and lower system storage (type II) shortfalls, these non-asset solutions can achieve a

number of positive social and economic impacts at low cost.

The solutions considered (except for the use of environmental entitlements) may also

encourage improved irrigation efficiency and alternatives to using water in peak periods (e.g.

on-farm storages). A signal of the value of water during peak times will encourage investment

in local solutions such as on-farm storage.

Each of the solutions is discussed in more detail in the following sections however a summary

of the results is provided in Table A- 1. Note, these solutions are an investigation option only;

no hydrological modelling will be undertaken and it remains a preliminary assessment only.

Table A- 1: Summary of assessment of non-asset solutions.



While this solution offers a neat way of managing the congestion, difficulties in establishing a well functioning market




reduces the efficiency


This option is likely to be costly and without an appropriate legislative backing would not be effective.

Use of environmental entitlements

Has potential to be an efficient and effective way of reducing the impacts of shortfalls as well as reducing total shortfalls altogether.

Incentive or congestion pricing measures

Difficult to assess whether pricing would provide the necessary incentives to change behaviour. Therefore not considered effective.

A.2 Tradable capacity shares

The capacity of the Barmah Choke is contributing to undesirable (unseasonal) flooding of the

Barmah-Millewa Forest and shortfalls to downstream irrigation areas. The operating capacity

of the Barmah Choke (10,600 ML/day as measured downstream of Yarrawonga Weir) could

act as a cap for the development of a market based instrument.

Permits could be used to allocate the capacity of the Barmah Choke (a „capacity share‟) to

irrigators, with permit holders given priority access during periods of congestion. The potential

exists for a capacity share product to be created which provides access rights to a share of the

available water flow during periods of congestion. These shares could then be tradable,

ensuring capacity is allocated to the highest value uses through an open market. The price of

capacity shares may provide an incentive for irrigators to manage their own demand during

periods of high water use, for example through the construction of on-farm storage. Depending

on the prices of capacity shares, there will also be an incentive to buy or sell these permits.

Additionally, once a capacity share has been allocated, private option contracts could be

created between irrigators. An options contract is a derivative product that attaches (in this

case) to the capacity share and would typically involve an agreement for future access in a

period of shortfall (i.e. when a trigger is activated). The contract usually involves the payment

of a „premium‟ at the time of signing and an exercise price at the time of option exercise.

During a shortfall period, options could then be exercised so that water would be delivered to

those who place the greatest value on it.

A.2.1 Potential risks and opportunities

There would be a number of potential risks associated with this option, primarily regarding the

development of a market. As noted by the Productivity Commission (2006), markets will

operate more efficiently where traders are heterogeneous (facing different marginal costs and

benefits). In contrast, where the market is thin and traders are comparable, with a similar

ability to pay for the tradable good, an active trading market may not result. This risk is

apparent in irrigation areas where similar types of crops are grown. However, if the market for



capacity shares extended from the Barmah Choke all the way downstream to the South

Australian Riverland and beyond there is likely to be diversity of crop types and hence the

potential for heterogeneous traders and therefore a better operating market.

Further work in this area would need to consider the following issues and risks associated with

the development of a market:

What are the legal requirements for a new product and design of a trading market?

How would the capacity share be divided between irrigators - should it be granted or

auctioned?

What legal considerations are required particularly relating to the development of a new

property right?

How might trading occur and would this create an unnecessary burden on irrigators?

Would administrative complexity outweigh potential benefits?

Is there likely to be an active market or will trading be thin?

Are there long enough periods between establishing a rationing event and allowing trade

of capacity so that it is managed efficiently?

Can a product be designed to be appropriate for different irrigation areas given difference

rationing procedures that are applied during shortfall events?

Despite this, the solution provides a method of allocating capacity to those irrigators who

require it most while provide a potential new revenue source to other irrigators.

A.2.2 Effectiveness and efficiency

While this approach offers a way of managing capacity constraints there are questions as to the

effectiveness and efficiency of such an approach. Effectiveness may be limited by lack of an

active market, both because shortfalls are not a regular occurrence, and because it may be

difficult for irrigators to assess appropriate prices. There is also the prospect of a lack of

trading due to similar players in the market.

Efficiency is also somewhat questionable. There is will be a high level of costs associated with

the establishment and operation of a trading market. Initially appropriate legislative and

administrative arrangements will need to be put in place to give the property right legal basis.

Further, policy constraints such as division of the available capacity between the basin States

would have to be resolved. If a market was developed, a high level of transaction costs

(relative to trade) level can be expected relating to fees and charges, potential brokerage fees

and costs associated with irrigators managing their new property right.

Overall, it is judged that this option is not likely to be an efficient or effective solution until

policy constraints are removed.



A.3 Use of environmental entitlements

Another potential solution is to ensure the use of significant holdings of environmental

entitlements (through agreements with holders) in periods when the Barmah Choke is not

congested and avoid their use when the Barmah Choke is congested.

A number of recent programs have meant environmental holdings have increased significantly

(although these are not all at the expense of consumptive entitlements). This has included large

Commonwealth funded programs, State based initiatives and joint Commonwealth and State

Based programs including The Living Murray and Water for the Future.

The water transfers could have a two-fold impact; firstly the transfers could reduce irrigator

demand downstream of the Barmah Choke and thereby reducing peak demand (where

purchases occur downstream of the Barmah Choke). Also, the water needs of environmental

assets may have more flexibility in the timing of watering events, allowing flexibility of when

and how the capacity of the Barmah Choke is used. Purchasing further entitlements

specifically to manage the capacity constraints is not considered a viable option. In the current

reform period, further entitlement purchases are unlikely to have political or irrigator support.

If these environmental water holdings were not used during a likely shortfall period, these

events would be reduced without the need for a significant capital expenditure. This could

occur through agreement with environmental water holders while acknowledging policy and

legislation constraints as to the time of its water use. Some of the current environmental water

acquisitions include:

The Living Murray: 472 GL of (long term cap equivalents).

The water is used to improve environmental health at six icon sites:

Barmah–Millewa Forest

Gunbower–Koondrook–Perricoota Forest

Hattah Lakes

Chowilla Floodplain and Lindsay–Wallpolla Islands

Lower Lakes, Coorong and Murray Mouth

River Murray Channel.

Many of these sites are downstream of the Barmah Choke and so will potentially increase the

pressure on the Barmah Choke as there is a potential timing issue with the possibility of

environmental managers using their entitlements at the same time as other entitlement holders.

Restoring the Balance (water buybacks through the Water for the Future program)

Table A- 2 shows that around 160 GL of entitlements of various security have been transferred

to the CEWH to date through the $3.1 billion program of water buybacks.



Table A- 2: Water buybacks below the Barmah Choke (at 30 June 2010).

Catchment Entitlement Type Secured Purchases (ML)

Murray NSW general security- below the Barmah Choke 32,598

Murray NSW high security- below the Barmah Choke 386

Murray Victoria high reliability- below the Barmah Choke 79,244

Murray Victorian low reliability- below the Barmah Choke 5,762

Murray SA high security 41,065

TOTAL 159,055

Source: http://www.environment.gov.au/water/policy-programs/entitlement-purchasing/2008-09.html

Further savings are being made through the Sustainable Rural Water Use and Infrastructure

program. Generally these are attained through infrastructure improvements which aim to save

water without impacting irrigator use so may actually worsen congestion if the resulting

environmental allocations pass through the Barmah Choke.

Basin Plan

The Commonwealth Water Act 2007 requires the Murray-Darling Basin Authority (MDBA) to

prepare and oversee a Basin Plan. This plan is a legally enforceable document that provides for

the integrated management of all the Basin‟s water resources.

A key element of the Basin Plan includes defining sustainable diversion limits (SDLs), which

are enforceable environmentally sustainable limits on the quantities of surface water and

groundwater that may be taken from Basin water resources. Implemenation of the Basin Plan

may result in existing entitlements being transferred from irrigators to the CEWH.


There are two main constraints for this solution:

1) Understanding the hydrological impacts of increased level of environmental entitlement

2) Gaining agreement with entitlements holders for altered watering plans.

This solution does provide a good opportunity to manage the constraint in the Barmah Choke

without imposing an additional burden on irrigators and without necessarily requiring

legislative change.


Establishing the effectiveness of this solution will require significant modelling effort. This is

beyond the scope of this project and will likely require a re-working of the current

hydrological models. Some evidence of reduced shortfalls is apparent through the modelling of

The Living Murray (TLM) initiative (Table A- 3) which is available within the current Murray

hydrological model. It shows that post-TLM, there will be a slight increase in undesirable

flooding and a slight reduction in the number of years with shortfalls, although a higher

proportion of the shortfalls that do occur will be classed „more difficult to manage‟ albeit with



lower average volumes and duration. Modelling of this solution would need to take into

account the potential optimisation between competing demands between environmental needs

and the capacity of the Barmah Choke.

Overall, TLM reference run results in a reduction in the total volume of shortfalls (of all types)

by 18 per cent but an increase of 13 per cent in the number of days of shortfalls.

Table A- 3: Shortfall and flooding indicator for Option 1 (pre-TLM) to a post-TLM reference run.

Indicator Option 1

(pre-TLM)

Post-TLM

Reference Run

Total years of undesirable flooding 63 73

Total years of moderate flooding 33 35

Total years of more severe flooding 29 32

% of years each side of the forest is wet 40% 43%

Shortfalls which are

expected to be

manageable

Number 13 6

Average volume (GL) 2.4 1.4

Average Duration (days) 3.4 2.7


expected to be

challenging to manage

Number 8 4




expected to be more

difficult to manage

Number 7 16



Total number of shortfalls 28 26

Some limited data is also available on the impact of reduced entitlements on peak demand.

Figure A- 1 shows that only when allocations are well below 100 per cent, does peak demand

fall significantly. If a reduction in allocation is considered a good proxy for the impact of

reduced entitlements, this suggests a very large reduction in entitlements could be required to

significantly reduce the peak demands which are associated with shortfalls.



Figure A- 1: Victorian peak daily demand and Victorian February allocation.

While further work is required to assess its effectiveness, this option is potentially highly

efficient. The major costs are already included as part of the Water for the Future program

meaning the costs associated with this option are largely the transaction costs associated with

reaching agreement with the CEWH or other bodies managing the Basin Plan (and

environmental watering plan) and overcoming any policy or legislative constraints if the

solution meant less than optimal environmental watering arrangements. The solution is

advantageous in that it would not require irrigator input, and could be managed by operators

and environmental water entitlement holders. In any case, this solution warrants further

investigation.

A.4 Covenants or options on entitlements

A covenant in general terms is an agreement to do or refrain from an act. Covenants have been

applied to land for example to prohibit building outside an agreed area to preserve surrounding

tress. More recently covenants have been used to protect remnant vegetation or achieve other

conservation goals (Bennett 2010). A covenant on entitlements could be placed (or purchased)

on a number of entitlements downstream of the Barmah Choke restricting the use of the

allocations associated with those entitlements in certain situations. In a period of capacity

constraints, the conditions of the covenant could be used to prevent some entitlement holders

gaining access to water deliveries during a shortfall period.

0

1000

2000

3000

4000

5000

6000

7000

8000

9000

10000

0 50 100 150 200 250

Vic

tori

an P

eak

Dai

ly D

em

and

fo

r W

ate

r Ye

ar

(ML/

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)

Victorian February Allocation (%)



An option contract could work in a similar manner. Option contracts could be entered into

between entitlement holders and the operators which allow them to prevent delivery of water

entitlements in a period of constraint (the „trigger‟). Options generally involve the payment of

an upfront fee (the „premium‟) and then a further fee if the option is exercised (the „exercise

price‟) by the operator to prevent supply (Scoccimarro and Collins 2006).


The main risk associated this approach is the policy and legislative backing required for

covenants. However the solution potentially provides irrigators with an additional revenue

source which could be used to manage irrigation risks associated with shortfalls.


Theoretically, there is potential for covenants to effectively manage capacity constraints but in

practice, the effectiveness of covenant is likely to be limited. Further modelling would be

required to calculate the number of entitlements required to have a covenant applied to ensure

that the volume of allocation causing the current capacity constraint can be reduced. Covenants

would be applied to entitlements however it is the use of entitlement holders‟ allocation which

causes the constraint through the Barmah Choke. These may not align reducing effectiveness

or meaning a much larger number of entitlements would require a covenant.

While each State has provisions allowing conditions to be applied to entitlements, a legislative

change would offer more certainty and could ensure the water registries reflect changes to the

entitlements conditions (Scoccimarro and Collins 2006). The Productivity Commission (2010)

in assessing the suitability for the covenants for environmental flows found „...unless a Torrens

titling system was developed for water rights, it would be difficult to implement and enforce

covenants. Given the challenges in harmonising state approaches to defining and managing

water rights, there are likely to be significant difficulties in implementing a universal system of

covenants.’

Option contracts share the same problems as covenants where the number of entitlements

which would need to be subject to option contracts is uncertain. There are likely to be a high

level of the transaction costs in setting the contractual arrangements required for covenants.

Option contracts would need to be tied to the entitlements, potentially restricting (or adding

costs) to trade. It is unlikely the legal and regulatory constraints can be overcome to ensure the

benefits outweigh the administrative costs created.

A.5 Incentive pricing

Incentive pricing would involve offering differential pricing when it is clear a shortfall event is

about to occur. That is when a short fall event is about to occur, discounts could be offered for

those prepared to delay their order with a corresponding increase in cost for those wanting to

progress with their order. The objective would be to provide an incentive for some irrigators to



delay orders while remaining revenue neutral for the operators. This approach could utilise

much of the research and information gained in congestion pricing implemented in a range of

fields such as transport and electricity pricing. It endeavours to make users aware of the

negative impact imposed on others when using water during peak demand. An incentive

pricing regime could ensure that those who have the greatest need for water deliveries during

peak demand periods will be able gain access, albeit for a higher price.


There are a range of risk and opportunities from this option including:

Irrigators may object to increases in prices (even if overall it is cost neutral)

This option would most likely require regulatory approval from both the Essential

Services Commission in Victoria and NSW‟s water price regulator, IPART. It is unclear

how the a new pricing structure could be implemented

Strategic behaviour on part of irrigators may be a risk

Incentive pricing provides a signal to irrigators in managing the capacity of the Barmah

Choke.


It is questionable how effective this system would be. A significant process would need to be

undertaken to set the discriminatory prices at a level which would alter behaviour. This is

likely to be uncertain and will require ongoing adjustments to provide sufficient incentive for

some irrigators to delay their orders. Given that these events are relatively infrequent, it may

be difficult for irrigators to understand the new system and react in a way that alleviates

shortfall events. The time period between a shortfall event being predicted to when discounted

prices would be offered and could be accepted is likely so short as unworkable.

There are other problems with this approach including the potential for strategic behaviour

whereby some irrigators will have an incentive to create congestion by placing orders when

shortfalls are likely in order to have access to reduced pricing. This is likely a minor issue as

placing unnecessary orders may result in unnecessary deliveries. Distributional and equity

issues would need to be considered further for this solution. Increasing prices would advantage

some irrigators over others. This may result in a perceived lack of fairness which would make

implementation more difficult. Overall this is not considered and effective or efficient solution.



Appendix B Option modelling methods

B.1 Option 1 – do nothing

The Investigation Phase of the Barmah Choke Study (SKM, 2009), found that the limited



through the Barmah-Millewa Forest.

This finding was based on the analysis the significance of the problem under the base case.

Since the Investigation Phase, the base case used by the MDBA for modelling assessments has

changed (the base case model adopted for this assessment was the pre-TLM reference run

model (user ID 1004TLM, run number 20506, run supplied April 2010). As such, the

significance of the problem under the base case has been re-assessed. The results of this

assessment are presented below.

The key difference between the base case used for the Investigation Phase and the base case

adopted for this phase relates to the assumed level of development. The base case used for the

Investigation Phase was developed from a currently conditions run which assumed current

(June 2008) level of development for demands and system operating practices, including TLM.

The base case used for this phase was developed from a pre-TLM reference run scenario which

assumed current (January 2010) level of development for demands and system operating

practices excluding any water recovery (or deployment) for TLM.

The most significant impact of moving to a pre-TLM reference run (from a partial-TLM run) is

a significant reduction (85.1 GL/year) in the volume of water entering the River Murray from

the Goulburn River. This is because under pre-TLM conditions, there is no delivery of TLM

water savings to the River Murray from the Goulburn River. This TLM water was supplied to

the River Murray over the peak summer irrigation period. The reduction in tributary inflows

downstream of the Barmah Choke means more water must be supplied through the Choke,

increasing the incidence and magnitude of shortfalls over what was reported for the

Investigation Phase.

Other changes include:

Murrubidgee inflows revised to incorporate Murrumbidgee Water Sharing Plan

environmental flows. This increased flow at Balranald by 93.6 GL/year, with most

changes occurring a low flows.

Snowy inflow revised to be based on modelled flows only (previously a combination of

modelled and observed flows). This increased River Murray releases by 8.4 GL/year and

unregulated Tooma spills by 11.4 GL/year.



Snowy model revised to be based on the dry inflow sequence volume. This reduces

forecast Snowy releases and leads to lower allocations.

Revised Menindee inflows as the Darling model has been undergoing continual

development including revision of losses. This increased Menindee inflows by 41

GL/year.

South Australian allocation and restriction system revised and rules for redistributing

South Australian restrictions over a year developed to match demand.

Minor revisions to Victorian tributary inflows:

Goulburn River inflows reduced by 1.1 GL/year

Campaspe River inflows reduced by 2.7 GL/year

Loddon River inflows increased by 0.1 GL/year

Torrumbarry system tributary inflows increased by 0.8 GL/year

Broken Creek inflows increased by 5.7 GL/year

Ovens River inflows reduced by 8.2 GL/year.

To revise the base case model for the Individual Options Phase, the pre-TLM reference run

model (user ID 1004TLM, run number 20506, run supplied April 2010) was initially run as

supplied.

Table B- 1 summarises the changes that were made to include the additional improvements for

modelling rainfall rejections developed as a part of the Investigation Phase (which have not

already been included in the model runs provided).

Table B- 1: Modifications made to the model as a part of the Investigation Phase and their status in the supplied pre-TLM reference run.

Modification made as a part of the Investigation Phase (SKM, 2009) Modifications required to the pre-TLM reference run

Updates to the model to use a new version of modflow which smooth‟s demands between months

Create a new version of modflwparaxxx.txt

Add column 14 to all lines, set to 0 for most, set to 4 (i.e. smoothed over 4 days) for Mulwala Cannal and Yarrawonga Channel at 8 m 3 ch weir

Copy the updated modflow exe (modflow-V357_SKMrev.exe) into the exe folder

Create a new copy of the ini file in the inifile folder (msm_bigmod_SKMrev.ini)

Under [MODFLOW] change EXEFILE and MODFILENAM to

reference the correct files.

The version of modflow and the modflow parameter file supplied (V492b-Modflow-Param.txt) includes the required changes- no further modifications required.

Column 14 is present in the parameter file and set to „4‟ for „Mulwala Canal‟ and „Yarrawonga Channel at 8 m 3 ch weir‟- no further modifications required.




Updates to the model to set channel capacity to 10,600 ML/day

Bigmod control variable 239 (Yarrawonga Channel capacity) should be 12 x 10600

MSM Card 68 (channel capacity d/s of Yarrawonga used for determining transfers to Lake Victoria) and Card 68a (Mandatory Yarrawonga Channel capacity) in GL/month (May- Apr), Jan = 328.6, Feb = 296.8, Mar = 328.6, Apr = 318.0

The MSM and Bigmod parameter files supplied include these changes.

One additional change is required. MSM Card 73 position 1 to 6, YARRABANKFULL (the flow in ML/day at which the banks are overtopped downstream of Yarrawonga) is currently set to 10200. For Option 1 this will be revised to 10600.

Updates to the Yarrawonga target level to improve rainfall rejection modelling

Bigmod control variable 265 (Targ Yarra Poll YMC > 2000 ML/day) should be 124.6 m AHD

Bigmod control variable 266 (Targ Yarra Pool YMC > 2800 ML/day) should be 124.6 m AHD

The Bigmod parameter file supplied uses these target levels- no further modification required.

Include additional outputs for the forest loss indicator

Under Reach Data

Add 1 to the number of reaches

Add: 153, 0, 1, 1, 0.0, 1886.2 „BARMAH LOSSES IN FOREST‟ after 129 “BARMAH FOREST)

This change is not in the parameter file supplied, however losses are modelled slightly differently and this is not required- no further modification required.

Under Reach Definition Data

Add 1 to the number of reaches defined

Add ? Reach 153- BARMAH LOSSES IN FOREST, after 129 (BARMAH FOREST) (copy same definition)


Under Branch Data

Change 3 „LOSSES IN FOREST‟

from: 18, 0.000, 0, 0, 0, 1, 1, 0, 16, 0

to: 18, 0.000, 153, 0, 0, 1, 1, 0, 16, 0


Under Control Variables

Add 7 to the number of control variables

Change 172 „NATIONAL CHANNEL DIVERSIONS‟

from: 9, 0.000, 0, 0, 0, 0, „F2‟, 6, 86

to: 9, 0.000, 1, 0, 0, 0, „F2‟, 6, 86

The supplied parameter file includes this modification- no further modification required.

Change 232 „MULWALA CANAL DIVERSION‟

from: 9, 0.000, 0, 0, 0, 0, „F2‟, 3, 50

to: 9, 0.000, 1, 0, 0, 0, „F2‟, 3, 50

Supplied parameter file does not include this modification. For Option 1 the modification will be made.




Add:

350 „INFLOW TO FOREST‟, 26, 0.000, 1, 0, 0, 0, „F1‟, 129, 1

351 „LOSSES IN FOREST‟, 26, 0.000, 1, 0, 0, 0, „F1‟, 153, 1

352 „Tuppal Ck‟, 26, 0.000, 1, 0, 0, 0, „FO‟, 44, 1

353 „Bullatale Ck‟, 26, 0.000, 1, 0, 0, 0, „FO‟, 45, 1

354 „Overbank Barmah‟, 26, 0.000, 1, 0, 0, 0, „FO‟, 19, 1

355 „Overbank Millewa‟, 26, 0.000, 1, 0, 0, 0, „FO‟, 46, 1

356 „Barmah Lake‟, 26, 0.000, 1, 0, 0, 0, „FO‟, 20, 1

After 520 „Moira Lake Rainfall‟ (all 12 x 0.)

The supplied parameter file includes the additional variables (different numbering)- no further modification required.

Updates to the model to predict demands (improved modelling of Lake Mulwala)

Under control variables add:

4 to the number of control variables

505 „Yesterday Mulwala Canal Diversion‟, 9, 0.000, 0, 0, 0, 0, „CV‟, 232, 50

232 „Mulwala Canal Diversions‟, 9, 0.000, 1, 0, 0, 0, „F2‟, 3, 50

508 „Yesterday Yarraw MC diversions‟, 9, 0.000, 0, 0, 0, 0, „CV‟, 245, 50

245 „Yarrawonga Cannel Diversions‟, 9, 0.000, 1, 0, 0, 0, „F2‟, 9, 70

507 „Increase in MC + YMC order >=0‟, 9, 0.000, 0, 0, 124, 0, „F2‟, 3, 50

509 „Pred increase MC + YMC order‟, 9, 0.000, 1, 0, 125, 0, „CV‟, 507, 50

Comment out original 232 „Mulwala Canal Diversion‟ and 245 „Yarrawonga Channel Diversions‟

The supplied parameter file includes these additional variables (different numbers)- no further modification required.

Under control variable combinations add:

2 to the number of combinations

124 „Change in MC + YMC order‟ 3 – CV 505 + CV 245 – CV 508

125 „Pred increase MC + YMC order‟ 1 * CN 2.0

The supplied parameter file includes these additional variable combinations- no further modification required.

B.2 Option 2 – alter the 6-inch rule to increase operational flexibility

Model changes have been made to both MSM and to Bigmod. A change to MSM was made to

adjust the Lake Hume operational loss equation (see Table B- 4) to represent the monthly

savings made due to the changes to the 6 inch rule. A number of changes to the Bigmod code

were required to be made to represent the daily changes to the rule and are described below.

To model the new rules for the rate of fall allowable at Doctors Point and Heywood, changes

were made to the special.f90 file of the Bigmod code as detailed in Table B- 2. The revised

flow-flow rating curves for Doctors Point and Heywood used to develop these changes are

detailed in Table B- 5 and Table B- 6 respectively, based on the flow-level rating curves

shown in Table B- 7 and Table B- 8respectively.



Table B- 2: Changes made to the Special.f90 Bigmod FORTRAN code to model Option 6 – increased flexibility in the 6 inch rule.

Change Code

Original $Revision: 124 $

!$Date: 2010-04-15 20:40:40 +1000 (Thu, 15 Apr 2010) $

Module SPECIAL_Mod

Contains

!*==SPECIAL.spg processed by SPAG 6.08Dc at 18:29 on 8 Mar 2001

!Last change: MDBC 29/07/2009 2:57:59 PM

SUBROUTINE SPECIAL(Vc,Icnp,Icn,Valcon,Id,Im,Iy,idays,Defcon, &

Fi,Flwin,Flwout, &

Otherd,Efflnt,Div,Evmdat,Dvmdat,Regval,Rlevel, &

Stolak,Wrsto,Vmiss,Flwbrn,Ihist, &

idatesalt,rchlos,rdvfac,irchdv,ievast,datlak, &

hedsto,ilkfld,iwrfld,iwlrch,LAkeTopReg,SIllakBase)

!modifications: dbs jan 1998 upper flow limit at doctors point added

!for use in calculating hume outflows

!special code 9 modified for same reason

!

!: JHM Mar 2001 Call to new Subroutine "TERcalc" added

!to boost the volume of water pre-released

!to provide targeted environmental releases

!(TER) for the Hume to Yarrawonga stretch.

!

!this subroutine contains special hardwired code for calculating

!control variables

!

!when a new variable is defined - add data to spectst to enable

!tests to be made of definition

use UTE

Use INTERP_Mod

Use INTERPOL_Mod

Use HUMESA_Mod

Use TERCALC_Mod

Use DARTFLOW_Mod

Use DARTSPIL_Mod

Use DAYSINM_Mod

Use BARRPUMP_Mod

Use PENTAL_Mod

Use COSTNEW_Mod

IMPLICIT NONE

Revised Module Avge4Day

Real,dimension(4) :: DrAvgeFlow,HeyAvgeFlow

Integer InitAvge,ndpfall,nheyfall

Real InpFlow,InpHeight,minheight,drminflow,heyminflow

End Module Avge4Day



Change Code

!$Revision: 124 $

!$Date: 2010-04-15 20:40:40 +1000 (Thu, 15 Apr 2010) $

Module SPECIAL_Mod

Contains

!*==SPECIAL.spg processed by SPAG 6.08Dc at 18:29 on 8 Mar 2001

!Last change: MDBC 29/07/2009 2:57:59 PM

SUBROUTINE SPECIAL(Vc,Icnp,Icn,Valcon,Id,Im,Iy,idays,Defcon, &

Fi,Flwin,Flwout, &

Otherd,Efflnt,Div,Evmdat,Dvmdat,Regval,Rlevel, &

Stolak,Wrsto,Vmiss,Flwbrn,Ihist, &

idatesalt,rchlos,rdvfac,irchdv,ievast,datlak, &

hedsto,ilkfld,iwrfld,iwlrch,LAkeTopReg,SIllakBase)

!modifications: dbs jan 1998 upper flow limit at doctors point added

!for use in calculating hume outflows

!special code 9 modified for same reason

!

!: JHM Mar 2001 Call to new Subroutine "TERcalc" added

!to boost the volume of water pre-released

!to provide targeted environmental releases

!(TER) for the Hume to Yarrawonga stretch.

!

!this subroutine contains special hardwired code for calculating

!control variables

!

!when a new variable is defined - add data to spectst to enable

!tests to be made of definition

use UTE

Use INTERP_Mod

Use INTERPOL_Mod

Use HUMESA_Mod

Use TERCALC_Mod

Use DARTFLOW_Mod

Use DARTSPIL_Mod

Use DAYSINM_Mod

Use BARRPUMP_Mod

Use PENTAL_Mod

Use COSTNEW_Mod

Use Avge4Day

IMPLICIT NONE

Original vicoutsto(15),TargetFlow(2), SATargetBP,lvicoutcal, &

vicoutflow(15),vicoutmax,tarlvlast,changemax, &

SAShortfallthismonth,wateruse(2),wateruse01(130), &

watervalue(20,2,2),swampfactor(2),RedbankShort,Aw,Ag,At,Ap, &

Apb,Awo,Agenoe,LVmaxPB,fillday,LAMinFlowFall,conv,InitSal, &

DIMENSION Valcon(Maxcon) , saent(12) , tarmen(12) , &

Defcon(Maxcon,12) , humfst(45) , dprise(6) , dpfall(6) , &



Change Code

dprisfal(6) , heyfallf(7) , heyfall(7) , Flwin(0:Maxrch) &

, Flwout(0:Maxrch) , Rlevel(0:Maxlev) , Stolak(Maxlak,2) &

, Wrsto(Maxwr,3) , Evmdat(0:Maxevm) , Dvmdat(0:Maxdvm) , &

Efflnt(Maxeff) , Div(Maxdiv) , Regval(Maxreg) , &

Otherd(0:Maxoth) , Flwbrn(Maxbrn) , vouttb(10,2) , &

lim(3) , cst(3) , secvlim(12,2) , mdbclim(12,2) , &

secvcst(12,3) , mdbccst(12,3), &

Revised vicoutsto(15),TargetFlow(2), SATargetBP,lvicoutcal, &

vicoutflow(15),vicoutmax,tarlvlast,changemax, &

SAShortfallthismonth,wateruse(2),wateruse01(130), &

watervalue(20,2,2),swampfactor(2),RedbankShort,Aw,Ag,At,Ap, &

Apb,Awo,Agenoe,LVmaxPB,fillday,LAMinFlowFall,conv,InitSal, &

dpfall9,heyfall9,dpheight,heyheight

DIMENSION Valcon(Maxcon) , saent(12) , tarmen(12) , &

Defcon(Maxcon,12) , humfst(45) , dprise(6) , dpfall(6) , &

dprisfal(6) , heyfallf(7) , heyfall(7) , Flwin(0:Maxrch) &

, Flwout(0:Maxrch) , Rlevel(0:Maxlev) , Stolak(Maxlak,2) &

, Wrsto(Maxwr,3) , Evmdat(0:Maxevm) , Dvmdat(0:Maxdvm) , &

Efflnt(Maxeff) , Div(Maxdiv) , Regval(Maxreg) , &

Otherd(0:Maxoth) , Flwbrn(Maxbrn) , vouttb(10,2) , &

lim(3) , cst(3) , secvlim(12,2) , mdbclim(12,2) , &

secvcst(12,3) , mdbccst(12,3), &

heyfall9(7),dpfall(6),dpheight(6),heyheight(7)

Original !limits for doctors point rise and fall

!

DATA dprisfal/0. , 814. , 5060. , 9990. , 20000. , 25100./

DATA dprise/1630. , 1676. , 2910. , 3410. , 4100. , 4300./

DATA dpfall/0. , 606. , 1300. , 1600. , 2000. , 2100./

!DATA dpfall/0. , 814. , 2199. , 3025. , 3950. , 3738./ ! for SKM study (Uttam), if maxm rate of fall allowed is increased to 300 mm

!

!limits for heywoods fall

!

DATA heyfallf/0. , 1000. , 6000. , 10000. , 15000. , 20000. , &

25100./

DATA heyfall/0. , 676. , 1620. , 2070. , 2300. , 2600. , 3000./

!DATA heyfall/0. , 847. , 2456. , 2975. , 3450. , 3754. , 4407./ ! for SKM study (Uttam), if maxm rate of fall allowed is increased to 300 mm

Revised !limits for doctors point rise and fall

!

DATA dprisfal/0. , 814. , 5060. , 9990. , 20000. , 25100./

DATA dprise/1630. , 1676. , 2910. , 3410. , 4100. , 4300./

DATA dpfall/0. , 606. , 1300. , 1600. , 2000. , 2100./

!DATA dpfall/0. , 814. , 2199. , 3025. , 3950. , 3738./ ! for SKM study (Uttam), if maxm rate of fall allowed is increased to 300 mm

Data dpfall9/0.,712.,1644.,2290.,2850.,2800./

Data dpheight/0.,1.44,2.16,2.67,3.48,2.89/

!

!limits for heywoods fall

!

DATA heyfallf/0. , 1000. , 6000. , 10000. , 15000. , 20000. , &



Change Code

25100./

DATA heyfall/0. , 676. , 1620. , 2070. , 2300. , 2600. , 3000./

!DATA heyfall/0. , 847. , 2456. , 2975. , 3450. , 3754. , 4407./ ! for SKM study (Uttam), if maxm rate of fall allowed is increased to 300 mm

Data heyfall9/0.,726.,1895.,2277.,2600.,2850.,3300./

Data heyheight/0.,1.34,2.04,2.45,2.90,3.30,3.66/

Original !calculate the acceptable rates of rise and fall at albury

!for pre-release

!

IF ( docflow.GE.25100. ) THEN

pflmin = 23000.

pflmax = 99999999.

ELSEIF ( docflow.LE.0. ) THEN

pflmax = 1630.

pflmin = 0.

ELSE

DO i = 2 , 6

IF ( docflow.LE.dprisfal(i) ) GO TO 20

ENDDO

i = 6

20 pflmax = docflow + dprise(i-1) + (docflow-dprisfal(i-1)) &

*(dprise(i)-dprise(i-1))/(dprisfal(i)-dprisfal(i-1))

pflmin = docflow - dpfall(i-1) - (docflow-dprisfal(i-1)) &

*(dpfall(i)-dpfall(i-1))/(dprisfal(i)-dprisfal(i-1))

ENDIF

pflmax = MAX(0.,pflmax-Valcon(65)+valcon(284))

pflmin = MAX(0.,pflmin-Valcon(65)+valcon(284))

!

!calculate the acceptable rates of fall at heywoods

!for pre-release

!20 cm per day

!

IF ( heyflow.GE.heyfallf(7) ) THEN

pflminhey = heyfallf(7) - heyfall(7)

ELSEIF ( heyflow.LE.0. ) THEN

pflminhey = 0.

ELSE

DO i = 2 , 7

IF ( heyflow.LE.heyfallf(i) ) GO TO 40

ENDDO

i = 7

40 pflminhey = heyflow - heyfall(i-1) - (heyflow-heyfallf(i-1)) &

*(heyfall(i)-heyfall(i-1)) &

/(heyfallf(i)-heyfallf(i-1))

ENDIF

!

!calculate the evaporation loss from the lake today

Revised !calculate the acceptable rates of rise and fall at albury

!for pre-release

!

If (InitAvge.ne.99) Then

DrAvgeFlow(:)=0.

HeyAvgeFlow(:)=0.



Change Code

InitAvge=99

ndpfall=0

nheyfall=0

End If

IF ( docflow.GE.25100. ) THEN

pflmin = 23000.

pflmax = 99999999.

ndpfall=0

ELSEIF ( docflow.LE.0. ) THEN

pflmax = 1630.

pflmin = 0.

ndpfall=0

ELSE

ndpfall=min(4,ndpfall+1)

DrAvgeFlow(4)=DrAvgeFlow(3)



DrAvgeFlow(1)=docflow

InpFlow=DrAvgeFlow(ndpfall)

Do i=2,6

If (InpFlow.le.dprisfal(i)) Exit

End Do

i=min(6,i)

InpHeight=dpheight(i-1)+((dpheight(i)-dpheight(i-1))*(InpFlow-dprisfal(i-1))/(dprisfal(i)-dprisfal(i-1)))

minheight=max(0.,InpHeight-0.6)

Do i=2,6

If (minheight.le.dpheight(i)) Exit

End Do

i=min(6,i)

drminflow=dprisfal(i-1)+((dprisfal(i)-dprisfal(i-1))*(minheight-dpheight(i-1))/(dpheight(i)-dpheight(i-1)))

DO i = 2 , 6

IF ( docflow.LE.dprisfal(i) ) GO TO 20

ENDDO

i = 6

20 pflmax = docflow + dprise(i-1) + (docflow-dprisfal(i-1)) &

*(dprise(i)-dprise(i-1))/(dprisfal(i)-dprisfal(i-1))

If ((docflow.lt.12000).or.(Im.ge.6).or.int(Valcon(995).eq.0) Then

pflmin = docflow - dpfall(i-1) - (docflow-dprisfal(i-1)) &

*(dpfall(i)-dpfall(i-1))/(dprisfal(i)-dprisfal(i-1))

Else

pflmin = docflow - dpfall9(i-1) - (docflow-dprisfal(i-1)) &

*(dpfall9(i)-dpfall9(i-1))/(dprisfal(i)-dprisfal(i-1))

End If

ENDIF

pflmin=max(pflmin,drminflow)

pflmax = MAX(0.,pflmax-Valcon(65)+valcon(284))

pflmin = MAX(0.,pflmin-Valcon(65)+valcon(284))

!

!calculate the acceptable rates of fall at heywoods

!for pre-release



Change Code

!20 cm per day

!

IF ( heyflow.GE.heyfallf(7) ) THEN

pflminhey = heyfallf(7) - heyfall(7)

nheyfall=0

ELSEIF ( heyflow.LE.0. ) THEN

pflminhey = 0.

nheyfall=0

ELSE

nheyfall=min(4,nheyfall+1)

HeyAvgeFlow(4)=HeyAvgeFlow(3)



HeyAvgeFlow(1)=heyflow

InpFlow=HeyAvgeFlow(nheyfall)

Do i=2,7

If (InpFlow.le.heyfallf(i)) Exit

End Do

i=min(7,i)

InpHeight=heyheight(i-1)+((heyheight(i)-heyheight(i-1))*(InpFlow-heyfallf(i-1))/(heyfallf(i)-heyfallf(i-1)))

minheight=max(0.,InpHeight-0.8)

Do i=2,7

If (minheight.le.heyheight(i)) Exit

End Do

i=min(7,i)

heyminflow=heyfallf(i-1)+((heyfallf(i)-heyfallf(i-1))*(minheight-heyheight(i-1))/(heyheight(i)-heyheight(i-1)))

DO i = 2 , 7

IF ( heyflow.LE.heyfallf(i) ) GO TO 40

ENDDO

i = 7

40 If ((docflow.lt.12000).or.(Im.gt.6).or.int(Valcon(995).eq.0) Then

pflminhey = heyflow - heyfall(i-1) - (heyflow-heyfallf(i-1)) &

*(heyfall(i)-heyfall(i-1)) &


Else

pflminhey = heyflow - heyfall9(i-1) - (heyflow-heyfallf(i-1)) &

*(heyfall9(i)-heyfall9(i-1)) &


End If

ENDIF

pflminhey=max(pflminhey,heyminflow)

!

!calculate the evaporation loss from the lake today

Table B- 3: Changes made to the Spectst.f90 Bigmod FORTRAN code to model Option 6 – increased flexibility in the 6 inch rule.

Change Code

Original !SPECIAL CODE 9



Change Code

!OUTFLOW FROM HUME DAM

!Control variables 199 to 205 added for TERCalc by JHM, March 2001

!Control variable 58 is the daily rainfall at Hume Dam (-ve)

!Control variable 59 is the daily evaporation at Hume Dam (* pan factor)

!Control variable 61 is the pre-release target at start of month

!Control variable 62 is the inflow to Hume Dam

!Control variable 64 is previous day's storage in Hume Dam

!Control variable 65 is the flow at Kiewa

!Control variable 66 is Yesterdays flow at Doctors Point

!Control variable 68 is the pre-release target at end of month

!Control variable 69 is the pre-release target at start of next month

!Control variable 70 flow at Jingellic

!Control variable 71 flow at Tallandoon

!Control variable 73 is min. Hume channel capacity

!Control variable 74 is max. Albury channel capacity - for irrigation releases

!Control variable 88 is Hume Dam max. safe storage

!Control variable 89 is Hume Dam storage that triggers flood mitigation

!Control variable 90 is estimated number of days to fill dam

!Control variable 91 is added percentage to Hume inflow

!Control variable 92 is yesterday's Hume Dam releases

!Control variable 94 is MSM end of month Hume Storage

!Control variable 113 is Switch for Dartmouth,Hume correction? 0=yes

!Control variable 115 is MSM Spill from Hume

!Control variable 117 is fraction of Hume Dam natural inflow passed

!Control variable 127 is yesterday's Hume natural inflows

!Control variable 128 is Albury pre-release channel capacity

!Control variable 170 is Albury Translucent release channel capacity

!Control variable 171 is Hume Translucent Special Rule

!Control variable 199 is the target flow to be reached by the TER

!Control variable 200 is the target duration of the TER (in days)

!Control variable 201 is the longest acceptable duration between floods (in days)

!Control variable 202 is the first month in which the TER is to be targeted

!Control variable 203 is the last month in which the TER is to be targeted

!UNUSED Control variable 281 is B-M option (if =1 then boost pre-releases when

!env. allocation is being used to flood B-M, if 0= then don't boost

!pre-releases)

!UNUSED Control variable 282 is the monthly use of the B-M allocation

!Control variable 249 is Hume Release for Hume Boost flows

!Control variable 250 is the Albury Flow from MSM

!Control variable 284 is the Hume to Albury Diversion and Loss

DATA (spconchk(9,i),i=1,35)/58,59,61,62,64,65,66,68,69,70,71, &

73,74,88,89,90,91,92,94,113,115,117,127,128,170,171, &

-199,-200,-201,-202,-203,249,250,284,0/

Revised !SPECIAL CODE 9

!OUTFLOW FROM HUME DAM

!Control variables 199 to 205 added for TERCalc by JHM, March 2001

!Control variable 58 is the daily rainfall at Hume Dam (-ve)

!Control variable 59 is the daily evaporation at Hume Dam (* pan factor)

!Control variable 61 is the pre-release target at start of month

!Control variable 62 is the inflow to Hume Dam



Change Code

!Control variable 64 is previous day's storage in Hume Dam

!Control variable 65 is the flow at Kiewa

!Control variable 66 is Yesterdays flow at Doctors Point

!Control variable 68 is the pre-release target at end of month

!Control variable 69 is the pre-release target at start of next month

!Control variable 70 flow at Jingellic

!Control variable 71 flow at Tallandoon

!Control variable 73 is min. Hume channel capacity

!Control variable 74 is max. Albury channel capacity - for irrigation releases

!Control variable 88 is Hume Dam max. safe storage

!Control variable 89 is Hume Dam storage that triggers flood mitigation

!Control variable 90 is estimated number of days to fill dam

!Control variable 91 is added percentage to Hume inflow

!Control variable 92 is yesterday's Hume Dam releases

!Control variable 94 is MSM end of month Hume Storage

!Control variable 113 is Switch for Dartmouth,Hume correction? 0=yes

!Control variable 115 is MSM Spill from Hume

!Control variable 117 is fraction of Hume Dam natural inflow passed

!Control variable 127 is yesterday's Hume natural inflows

!Control variable 128 is Albury pre-release channel capacity

!Control variable 170 is Albury Translucent release channel capacity

!Control variable 171 is Hume Translucent Special Rule

!Control variable 199 is the target flow to be reached by the TER

!Control variable 200 is the target duration of the TER (in days)

!Control variable 201 is the longest acceptable duration between floods (in days)

!Control variable 202 is the first month in which the TER is to be targeted

!Control variable 203 is the last month in which the TER is to be targeted

!UNUSED Control variable 281 is B-M option (if =1 then boost pre-releases when

!env. allocation is being used to flood B-M, if 0= then don't boost

!pre-releases)

!UNUSED Control variable 282 is the monthly use of the B-M allocation

!Control variable 249 is Hume Release for Hume Boost flows

!Control variable 250 is the Albury Flow from MSM

!Control variable 284 is the Hume to Albury Diversion and Loss

!Control variable 995 is whether the 9 inch rule is engaged or not 1=yes, 0=no

DATA (spconchk(9,i),i=1,36)/58,59,61,62,64,65,66,68,69,70,71, &

73,74,88,89,90,91,92,94,113,115,117,127,128,170,171, &

-199,-200,-201,-202,-203,249,250,284,995,0/

Table B- 4: Changes made to the V542-MSMConstants.csv MSM model to account for changes in losses for Option 6 – increased flexibility in the 6 inch rule.

Change Parameters

Original Constant term in the equation to estimate operational losses (May to April),valmon,"12,0,0,0",,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,

,,,64,17.9,54.5,37.9,59.7,174.6,174.6,174.6,194.6,232.8,276.4,128.9,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,

Revised Constant term in the equation to estimate operational losses (May to April),valmon,"12,0,0,0",,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,

,,,62.3,17.9,54.5,37.9,59.7,174.6,174.6,174.6,191.8,229.9,273.8,126.3,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,



Table B- 5: Doctors Point Flow-Flow rating curves.

Flow at Doctors Point (ML/day)

Allowable Rise (ML/day)

6 inch fall (ML/day) 9 inch fall (ML/day)

0 1630 0 0

814 1676 606 712

5060 2910 1300 1644

9990 3410 1600 2290

20000 4100 2000 2850

25100 4300 2100 2800

Table B- 6: Heywoods Flow-Flow rating curves.

Flow at Heywoods (ML/day)

Allowable Rise (ML/day)

8 inch fall (ML/day) 9 inch fall (ML/day)

0 N/A 0 0

1000 N/A 676 726

6000 N/A 1620 1895

10000 N/A 2070 2277

15000 N/A 2300 2600

20000 N/A 2600 2850

25100 N/A 3000 3300

Table B- 7 Doctors Point Flow-Level rating curves.

Flow at Doctors Point (ML/day) Level at Doctors Point (m)

0 0.00

814 1.44

5060 2.16

9990 2.67

20000 3.48

25100 3.89

Table B- 8: Heywoods Flow-Level rating curves.

Flow at Heywoods (ML/day) Level at Heywoods (m)

0 0.00

1000 1.34

6000 2.04

10000 2.45

15000 2.90

20000 3.30

25100 3.66



B.3 Option 3a – policy options to manage within the capacity of the Barmah Choke: Lake Victoria transfers

To model the transfer of water from Lake Hume to Lake Victoria earlier in the season, changes

were made to the monthly minimum target storages for Lake Victoria in the MSM parameter

file, and the channel capacity downstream of Yarrawonga which is used when the transfers are

modelled. Three combinations of modifications to the minimum target storages and channel

capacity are trialled (Table B- 9; Figure B- 1 and Figure B- 2).

Table B- 9: Changes made to the MSM parameter file to model Option 3a – earlier transfers from Lake Hume to Lake Victoria.

Original Parameter File Variable and Original Values

V551-MSM-TLM_Option1.txt ? 29 5 1-72 VALIN(I,50). TARGET MINIMUM STORAGES IN LAKE

VICTORIA

? FOR ASDT. [NB this is for months June to May]

140. 140. 180. 200. 200. 200. 200. 200. 200. 200. 180. 250.

29-5

? 68 1-72 BARCP1. CHANNEL CAPACITY D/S OF YARRAWONGA

USED FOR

? Determining Transfers to Lake Victoria

328.6 425.0 425.0 425.0 501.0 661.0 661.0 425.0 328.6 296.8

328.6 318. 68

New Parameter File New Values

V551-MSM-TLM_Option3a1.txt (trial 1)

250. 250. 250. 250. 250. 250. 200. 200. 200. 200. 180. 250.

29-5

328.6 425.0 425.0 425.0 501.0 661.0 661.0 425.0 248.0 224.0

248.0 240. 68


165. 165. 250. 300. 400. 400. 300. 200. 200. 200. 180. 165.

29-5

328.6 425.0 425.0 425.0 501.0 661.0 661.0 425.0 186.0 168.0

186.0 180. 68


300. 300. 300. 400. 500. 500. 400. 200. 200. 200. 180. 300.

29-5

328.6 425.0 425.0 425.0 501.0 661.0 661.0 425.0 186.0 168.0

186.0 180. 68



Figure B- 1: Modelled minimum storage targets for Lake Victoria for the base case

and Option 3a.

Figure B- 2: Modelled channel capacities downstream of Yarrawonga for

determining transfers from Hume to Lake Victoria under the base case and Option 3a.

0

100

200

300

400

500

600

May Jun Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr

Targ

et M

inim

um

Sto

rage

in L

ake

Vic

tori

a (G

L)Option 1 (Base Case)

Option 3a (trial 1)

Option 3a (trial 2)

Option 3a (trial 3)

0

100

200

300

400

500

600

700

May Jun Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr

Ch

ann

el C

apac

ity

D/S

of

Yarr

awo

nga

fo

r D

ete

rmin

ing

Tran

sfe

rs to

Lak

e V

icto

ria

(GL)

Option 1 (base case)

Option 3a (trial 1)

Option 3a (trial 2&3)



The changes to both the minimum storage target for Lake Victoria and the channel capacity for

transfers should result in:

Transfers being made earlier in the season;

Larger early season transfers; and

Fewer and smaller transfers during the unseasonal flooding period (January to April).

A preliminary test run was undertaken assuming the changes described in Table B- 9. The

preliminary test results indicated that:

In generally wet periods where there are no transfers from Hume to Lake Victoria under

the base case, the modelled changes made no difference to the transfers from Hume or the

Lake Victoria storage (e.g. Figure B- 3).

The modelled changes increase early season transfers, with the increase in transfers

generally being in the order of trial 1 (smallest increase) to trial 3 (largest increase). The

increased transfers from Hume are reflected in the Lake Victoria storage trace until the

storage reaches FSL (677 GL) (e.g. Figure B- 4 and Figure B- 5).

The modelled changes reduce the transfers from Hume to Lake Victoria in the undesirable

flooding period (Figure B- 6), with trial 2 resulting in the fewest transfers between

January and April.

The modelled changes increase the transfers from Hume to Lake Victoria between May

and December, with the largest increase being observed under trial 3 (Figure B- 7).

There is little difference in the storage exceedance curves for the base case and trial 1 of

Option 3a. Under trial 2 and 3, the volume of water stored in Lake Victoria increases

compared with the base case (Figure B- 8).

To increase transfers from Hume to Lake Victoria in the months from May to December

often requires releasing more water during wet periods, which in turn increases the

volumes of water that is predicted to flow overbank (e.g. through the Millewa forest,

Figure B- 9).



Figure B- 3: June 1956 to May 1958 Lake Victoria storage (LVStor) under base case

(_BC) conditions, and trial 1 (_1), trial 2 (_2) and trial 3 (_3) of Option 3a, compared with transfers from Lake Hume to Lake Victoria (HVLTRN) for the same scenario.



Hum

e to

Lak

e Vi

ctor

ia t

rans

fer

(GL)

0

50

100

150

200

250

300

350

Jul -56 Sep-56 N ov-56 Jan-57 Mar-57 May-57 Jul -57 Sep-57 N ov-57 Jan-58 Mar-58 May-58

HL VT RN _B C

HL VT RN _1

HL VT RN _2

HL VT RN _3

Lake

Vict

oria

storag

e (G

L)

0

100

200

300

400

500

600

700L VStor_B C

L VStor_1

L VStor_2

L VStor_3

Hum

e to

Lak

e Vi

ctor

ia t

rans

fer

(GL)

0

50

100

150

200

250

300

350


HL VT RN _B C

HL VT RN _1

HL VT RN _2

HL VT RN _3

Lake

Vict

oria

storag

e (G

L)

0

100

200

300

400

500

600

700L VStor_B C

L VStor_1

L VStor_2

L VStor_3





Figure B- 6: Frequency exceedance curves for transfers from Lake Hume to Lake

Victoria (HLVTRN) under base case (_BC) conditions, and trial 1 (_1), trial 2 (_2) and trial 3 (_3) of Option 3a, for the months of January to April.

Hum

e to

Lak

e Vi

ctor

ia t

rans

fer

(GL)

0

50

100

150

200

250

300

350


HL VT RN _B C

HL VT RN _1

HL VT RN _2

HL VT RN _3

Lake

Vict

oria

storag

e (G

L)

0

100

200

300

400

500

600

700L VStor_B C

L VStor_1

L VStor_2

L VStor_3

T ime Exceeded (%)

0 2 4 6 8 10 12 14 16 18 20

Hum

e to

Lak

e Vi

ctor

ia tra

nsfe

r (G

L/m

onth

)

10-1

100

101

102

HL VTRN _B C

HL VTRN _1

HL VTRN _2

HL VTRN _3



Figure B- 7: Frequency exceedance curves for transfers from Lake Hume to Lake

Victoria (HLVTRN) under base case (_BC) conditions, and trial 1 (_1), trial 2 (_2) and trial 3 (_3) of Option 3a, for the months of May to December.

Figure B- 8: Frequency exceedance curves for Lake Victoria storage (LVStor) under

base case (_BC) conditions, and trial 1 (_1), trial 2 (_2) and trial 3 (_3) of Option 3a, for all months.

T ime Exceeded (%)

0 2 4 6 8 10 12 14 16 18 20

Hum

e to

Lak

e Vi

ctor

ia t

rans

fer

(GL/

mon

th)

10-1

100

101

102

HL VTRN _B C

HL VTRN _1

HL VTRN _2

HL VTRN _3

T ime Exceeded (%)

20 30 40 50 60 70 80 90 100

Lak

e V

icto

ria

sto

rag

e (G

L)

2* 102

3* 102

4* 102

5* 102

6* 102

7* 102

L VStor_B C

L VStor_1

L VStor_2

L VStor_3



Figure B- 9: Outflows from Hume (Hume Out) versus overbank flows through the

Millewa Forest (OverBk Mill) under base case (_BC) conditions, and trial 2 (_2) of Option 3a.

B.4 Option 3b – policy options to manage within the capacity of the Barmah Choke: inter-valley trade

Rules relating to the use of inter-valley trade water are included in MSM, as shown below:

MSM Code 92

Volume of Goulburn high reliability entitlement- 109.418 GL

Volume of Goulburn low reliability entitlement- 0 GL

Volume of Murrumbidgee high security entitlement- 0 GL

Volume of Murrumbidgee general security entitlement- 0 GL

MSM Code 92-1, and 92-2 (both same)

Goulburn maximum fraction of remaining EVA balance that can be used this month Jan – Dec) and

Murrumbidgee maximum fraction of remaining EVW balance that can be used this month (Jan – Dec)

0.357 0.556 1.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.050 0.263

MSM Code 92-3 and 92-6 (both same)

Goulburn minimum upstream order before EVA called out (Jan – Dec) and Murrumbidgee minimum

upstream order before EVA called out (Jan –Dec)

-9999. -9999. -9999. -9999. -9999. -9999. -9999. -9999. -9999. -9999. -9999. -9999.

Over

bank

thro

ugh

Mill

ewa

Fore

st (M

L)

0

2000

4000

6000

8000

10000

12000

14000

16000

18000

20000

Mar89 May89 Jul89 Sep89 N ov89 Jan90 Mar90

OverB k M i l l_B C

OverB k M i l l_2

Outfl

ow f

rom

Hum

e (M

L)

0

5000

10000

15000

20000

25000

30000

35000

40000

Hume Out_B C

Hume Out_2



To examine the potential impact on shortfalls, the pattern for the „maximum fraction of the

remaining EVA balance that can be used this month‟ (MSM Code 92-1 and 92-2) was

modified.

Note that as only the Goulburn system contains inter-valley trade water in the base case

(Option 1), alternative inter-valley trade release rules were trialled on the Goulburn only.

The proposed „maximum fraction of the remaining EVA balance that can be used this month‟

is outlined below (MSM Code 92-1 and 92-2). The values represent accumulated percentage

available from January to December. The percentages were determined based on the

percentage of shortfalls occurring in each month.

0.651 0.957 1.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.199

B.5 Option 4 – increased operational flexibility in existing assets: Mildura Weir

The proposed modelling methodology for Option 4 is the same as adopted for modelling of

Euston Weir (Option 6). This involved using the MSM-Bigmod output from the „do-nothing‟

option in combination with the shortfall indicator which includes the ability to draw on

Mildura Weir active volume and order replenishment flow to refill the weir pool when channel

capacity is available.

The calculation of required flow at downstream Yarrawonga Weir is a function of the demands

plus losses less expected inflows downstream of Yarrawonga Weir (with allowances for travel

times considered). Table B- 10 outlines the methodology and components used to calculate

required flow at downstream Yarrawonga Weir.

Table B- 10: Calculation of required flow at downstream Yarrawonga Weir.

Component

Contribution to flow at Yarrawonga (+

ve or –

ve)

Lag (days in advance)

Model component used

Edward offtake + 3 Modelled Edward offtake flows from Bigmod

Gulpa offtake + 3 Modelled Gulpa offtake flows from Bigmod

Broken Creek inflows - 4 Modelled inflows from Bigmod

Goulburn River inflows - 4 Modelled inflows from Bigmod

National Channel orders + 6 National Channel Diversions from Bigmod

Loss Yarrawonga – Torrumbarry

+ 6 Loss (evap loss + short evap) for Yarrawonga to Torrumbarry, plus monthly Yarrawonga to Torrumbarry PD demands (restricted for channel capacity) plus Victorian shortfalls due to channel capacity all from MSM. Disaggregated based on a calibrated daily pattern from PRIDE.

Pental Island orders + 9 Pental Island pumps diversions from Bigmod.

Leiwah inflows - 9 Modelled inflows from Bigmod



Component


ve or –

ve)



Stoney inflows - 9 Modelled inflows from Bigmod

Swan Hill orders + 10 Calculated as 0.745 times Channel 9 diversions (from Bigmod)

Balranald inflows - 11 Modelled inflows from Bigmod

Loss Torrumbarry – Wakool Junction

+ 14 Loss (evap loss + short evap) for Torrumbarry to Wakool Junction, plus monthly Torrumbarry to Wakool Junction PD demands (restricted for channel capacity) all from MSM. Disaggregated based on a calibrated daily pattern from PRIDE.

Loss Wakool Junction – Euston

+ 14 Assumed to be 40% of loss from Wakool Junction to Wentworth

Required flow at Euston + 14 Minimum of Sunraysia diversions (4 days in advance from MSM2Big) and the sum of Sunraysia diversions (4 days in advance) plus Loss Euston to Wentworth (60% of loss Wakool Junction to Wentworth) plus required flow at Wentworth (minimum of zero).

Required flow at Wentworth

+ 14 Loss Wentworth to Rufus River plus 250 (minimum Lake Victoria inflow), plus the maximum of SA regulated flow less Lake Victoria outlet flow (2 days in advance) and 400 (minimum flow at Lock 7) less flow at Burtundy if Lake Victoria is able to supply the SA regulated flow or the maximum possible flow otherwise* if Lake Victoria is unable to supply the SA regulated flow.

*- Maximum possible flow (at Burtundy) equals minimum flow at Weir 32 if the Menindee Lakes are under

NSW control or otherwise the sum of the release capacity from Wetherell, Pamamaroo and Menindee

less loss from Weir 32 to Burtundy.

This calculation of required flow can be readily adapted to include the ability to temporarily

drawdown Mildura Weir to meet peak demands.

To simulate the drawdown of Mildura Weir to meet peak demands and avoid shortfalls in the

indicator the daily shortfall volume was reduced by the volume of drawdown available in

Mildura Weir, restricted by the required flow at Wentworth (14 days in advance) and a

maximum allowable rate of drawdown (if applicable).

Mildura Weir was assumed to be rapidly drawn down from the start of the shortfall event, and

refilled as soon as spare capacity for transfers becomes available. It was assumed that there

was no constraint in terms of a maximum allowable rate of refill.

B.6 Option 5 – lower operating level in Lake Mulwala

To model a lower operating level for Lake Mulwala, the target pool level was changed in the

Special.f90 BigMod fortran file (Table B- 11) that was used to model the base case (Option 1).



Table B- 11: Changes made to the Special.f90 BigMod fortran file to model Option 5a and 5b – lowering the operating level in Lake Mulwala.

Revision Type Code

Original ELSEIF ( Icnp.EQ.42 ) THEN

!SPECIAL CODE 42

!Doctors Point Order AFC Method

!

!Control variable 20 - Order Downstream of Yarrawonga

!Control variable 223 - Diversions from Albury to Yarrawonga

!Control variable 224 - Losses from Albury to Yarrawonga

!Control variable 232 - Mulwala Canal Diversions

!Control variable 245 - Yarrawonga Main Channel Diversions

!Control variable 246 - Wangaratta Flow(0.88 for 1 days 500 ML/d)

!Control variable 247 - Albury Minimum Flow

!Control variable 74 - Albury Channel Capacity for Regulated Releases

!Control variable 177 - Yarrawonga Pool Level yesterday

!Control variable 66 - Yesterdays Doctors Point Flow

!Control variable 265 - Target Level in Yarrawonga Pool If Yarrawonga main Channel < 2000 ML/d => 124.65

!Control variable 266 - Target Level in Yarrawonga Pool If Yarrawonga main Channel > 2800 ML/d => 124.65

!Control variable 781 - Twice the net increase in Yarrawonga Channel and Mulwala Canal yesterday

!

!Calculate Target Level in Yarrawonga Pool

!If Yarrawonga main Channel < 2000 ML/d => 124.65

!If Yarrawonga main Channel > 2800 ML/d => 124.80

!Vary linearly in between 2000 and 2800 Ml/d

!

!yarrawongaTarget=max(124.65,min(124.80,124.65+

!& 0.15*(valcon(245)-2000.)/800.))

yarrawongaTarget=max(valcon(265),min(valcon(266),valcon(265)+ &

0.15*(valcon(245)-2000.)/800.))

!Aim to get back to Target Level in 6 days

!Neither Yarrawonga Main Channel or Mulwala Canal included in reach diversions

!Correction for Yarrawonga Main Channel 16-6-2004

if(valcon(177).lt. 120.)then

valcon(177)=yarrawongaTarget

endif

Revised (5a) ELSEIF ( Icnp.EQ.42 ) THEN

!SPECIAL CODE 42


!




Revision Type Code













!





!


!& 0.15*(valcon(245)-2000.)/800.))

If (Im.ge.1.and.Im.le.4) Then

valcon(265)=124.50

valcon(266)=124.50

Else

valcon(265)=124.60

valcon(266)=124.60

End If


0.15*(valcon(245)-2000.)/800.))






endif

Revised (5b) ELSEIF ( Icnp.EQ.42 ) THEN

!SPECIAL CODE 42


!




Revision Type Code













!





!


!& 0.15*(valcon(245)-2000.)/800.))

If (Im.ge.1.and.Im.le.4) Then

valcon(265)=124.10

valcon(266)=124.10

Else

valcon(265)=124.60

valcon(266)=124.60

End If


0.15*(valcon(245)-2000.)/800.))






endif

B.7 Option 6 – enlarged storage capacity in Euston Weir

As discussed as a part of the Investigation Phase (SKM, 2009), daily shortfalls are not

calculated by MSM-Bigmod.



Shortfalls are calculated on a monthly time-step by MSM: if demand for a given month is in

excess of available channel capacity a shortfall is recorded. Calculating shortfalls on a monthly

time-step was determined to be unsuitable for the purposes of the Barmah Choke Study as

shortfalls occurring over short time periods are not identified. Daily shortfalls are not

calculated directly by Bigmod as the demands passed to Bigmod from MSM have already been

restricted based on monthly channel capacity.

For this reason it was necessary to develop an alternative method of calculating shortfalls on a

daily time-step. To understand the likelihood of shortfalls on a daily time-step, a method was

developed to determine required flow at downstream Hume Reservoir and downstream

Yarrawonga Weir based on model outputs. Required flow was then compared to operational

channel capacity to calculate shortfalls.

As such, it was proposed to model this option using the MSM-Bigmod output from the „do-

nothing‟ option in combination with the shortfall indicator which includes the ability to draw

on Euston Weir active volume and order replenishment flow to refill the weir pool when

channel capacity is available.






Component


ve or –

ve)











Edward River at Leiwah inflows

- 9 Modelled inflows from Bigmod

Wakool River Stoney inflows




Component


ve or –

ve)




Murrumbidgee Balranald inflows










NSW control or otherwise the sum of the release capacity from Wetherell, Pamamaroo and Menindee

less loss from Weir 32 to Burtundy.

This calculation of required flow was adapted to include the ability to temporarily drawdown

Euston Weir to meet peak demands. To simulate the drawdown of Euston Weir to meet peak

demands and avoid shortfalls, the daily shortfall volume calculated by the shortfall indicator

was reduced by the volume of drawdown available in Euston Weir. Following a drawdown

event, Euston Weir is refilled as soon as spare capacity for transfers becomes available.

B.8 Option 7 – Storage at “The Drop” on Mulwala Canal

This option includes construction of a storage at The Drop on Mulwala Canal. The storage

would be operated empty as much as possible to provide air space for capturing rainfall

rejections. The storage would be filled up to capacity (limited by the capacity of the inlet

infrastructure) to avoid River Murray flows greater than 10,600 ML/day throughout the

unseasonal flooding period and then rapidly drawn down following the end of the event (by

supplying downstream irrigators, limited by the capacity of the outlet infrastructure).

This option considers four sub-options (alternative storage capacities and inlet and outlet

capacities) as outlined in Table B- 13.



Table B- 13: The Drop storage and inlet and outlet criteria

Option Storage Capacity

(ML) Inlet Capacity

(ML/day) Outlet Capacity

(ML/day)

A 1000 1000 500

B 5000 1000 500

C 11000 9000 3000

D 16000 9000 3000

These options were examined through a spreadsheet approach looking at unseasonal flooding.

B.9 Option 10 – Victorian forest channels

In MSM-Bigmod, there are three branches that take water from the main stem of the River

Murray to the Barmah Forest: INFLOW TO FOREST, OVERBANK THROUGH BARMAH

and VICTORIAN REGS D/S PICNIC PNT. Table B- 14 shows the specification of these

branches in Bigmod.

Table B- 14: Branches in Bigmod that take water from the main stem of the River Murray through the Barmah Forest. The three rows of values are flow in the main stem (reach 18 (Tocumwal to Picnic Point) for INFLOW TO FOREST and OVERBANK THROUGH BARMAH and reach 128 (Picnic Point to Creeks) for VICTORIAN REGS D/S PICNIC PNT), flow in the branch when regulators are closed and flow in the branch when regulators are open.

V125-bigpar-prod_Option1.txt - Variable and Original Values

40 'INFLOW TO FOREST' 18 0.000 129 0 0 1 1 0 16 0

0. 3000. 11400. 12250. 15000. 25000. 35000. 48000. 50500. 63000. 67100. 90000. 115000. 125000. 140000. 200000.

0. 0. 0. 0. 20. 400. 500. 2900. 2900. 3400. 3400. 3400. 10330. 15900. 30900. 30900.

0. 0. 0. 0. 70. 400. 500. 2900. 2900. 3400. 3400. 3400. 10330. 15900. 30900. 30900.

2 'OVERBANK THROUGH BARMAH' 18 0.000 19 0 0 1 1 0 16 0

0. 3000. 11400. 12250. 15000. 25000. 35000. 48000. 50500. 63000. 67100. 90000. 115000. 125000. 140000. 200000.

0. 140. 490. 760. 2080. 8700. 16100. 18100. 18600. 19300. 20000. 20800. 21870. 22300. 22300. 22300.

0. 280. 1610. 1880. 2430. 9400. 16700. 18100. 18600. 19300. 20000. 20800. 21870. 22300. 22300. 22300.

9 'VICTORIAN REGS D/S PICNIC PNT' 128 1.000 20 0 0 2 1 0 10 0

0. 3600. 4250. 5000. 6000. 7000. 8000. 8500. 8950. 15000.

0. 0. 0. 0. 0. 0. 0. 0. 0. 1500.

0. 0. 106. 142. 207. 336. 503. 647. 873. 1500.

The branch INFLOW TO FOREST flows to a lake titled „Barmah Forest‟, which does not

reconnect to the main stem of the River Murray in most conditions (some water stored in

Barmah Forest „branches‟ over to the Gulpa junction in very large floods). Flow in the

branches OVERBANK THROUGH BARMAH and VICTORIAN REGS D/S PICNIC PNT

discharges to a lake titled „Barmah Lake‟, which reconnects to the River Murray immediately



downstream of the Barmah Choke. To model a bypass route around the Barmah Choke

through the Victorian forest channels, changes would be made to the Bigmod parameter file,

so that the OVERBANK THROUGH BARMAH branch took additional flow while the

regulators are closed as shown in Table B- 15.

Table B- 15: Modelling a bypass route around the Barmah Choke through the Victorian forest channels.

V125-bigpar-prod_Option1.txt - Variable and Original Values

2 'OVERBANK THROUGH BARMAH' 18 0.000 19 0 0 1 1 0 16 0

0. 3000. 11400. 12250. 15000. 25000. 35000. 48000. 50500. 63000. 67100. 90000. 115000. 125000. 140000. 200000.

0. 140. 490. 760. 2080. 8700. 16100. 18100. 18600. 19300. 20000. 20800. 21870. 22300. 22300. 22300.

0. 280. 1610. 1880. 2430. 9400. 16700. 18100. 18600. 19300. 20000. 20800. 21870. 22300. 22300. 22300.

V551-MSM-TLM_Option10.txt - New Values

0. 3000. 10600. 11000. 11400. 12250. 15000. 25000. 35000. 48000. 50500. 63000. 67100. 90000. 125000. 200000.

0. 140. 457. 857. 1290. 2410. 2500. 8700. 16100. 18100. 18600. 19300. 20000. 20800. 22300. 22300.

0. 280. 1483. 1484. 1610. 1880. 2430. 9400. 16700. 18100. 18600. 19300. 20000. 20800. 22300. 22300.

The changes would be such that, for the regulator closed option:

When flows at Tocumwal are below 10,600 ML/d, the flow branching to Barmah Lake

would be as previously modelled,

When flows at Tocumwal are above 10,600 ML/d, the flow branching to Barmah Lake

would be the sum of that previously modelled, plus the difference between flow at

Tocumwal and 10,600 ML/d, and

A judgement would be made about where the „Option10 – regulator closed‟ and „base case

– regulator closed‟ curves would rejoin (Figure B- 10).



Figure B- 10: Regulator open and closed comparison

This change to the Bigmod parameter file increased the volume of water flowing to Barmah

Lake when the regulators which are used to control flooding of the forest are closed (Figure B-

11). At times, these increases would coincide with rainfall-rejection events. At other times,

modelled flows to Barmah Lake would be greater than in the base case for long periods,

despite the small likeliness of this happening in practice. However, this second situation is not

expected to affect modelled flows outside the reach between Picnic Point and the Barmah

Choke, and will not be reflected in the indicators used to measure the effectiveness of options

for managing shortfalls used in the Barmah Choke Study.

0

5000

10000

15000

20000

25000

0 10000 20000 30000 40000 50000

Flo

w t

hro

ugh

Bar

mah

Fo

rest

(re

ach

19

) (M

L/d

)

Flow at Tocumwal (ML/d)

Regulator closed (base case)

Regulator open (base case)

Regulator closed (option 10)



Figure B- 11: Modelled flows at Tocumwal, to Barmah Lake and at Picnic Point

under the base case (_BC) and option 10 (_10). In 2001/02 the increased flows through the Victorian forest channels coincides with apparent rainfall-rejection events in January and March. However, in 2002/03, there is a long period where flow through the channels is greater than in the base case. Refer to the previous page for a discussion.

Flo

w (

ML

/d)

0

2000

4000

6000

8000

10000

12000

14000

D ec00 Jan01 Feb01 Mar01 A pr01 May01

T ocumw al_B C

T o B armah L k_B C

T ocumw al_10

T o B armah L k_10

Picnic_B C

Picnic_10

Flo

w (

ML

/d)

0

2000

4000

6000

8000

10000

12000

14000

16000

Oct02 N ov02 D ec02 Jan03 Feb03

T ocumw al_B C

T o B armah L k_B C

T ocumw al_10

T o B armah L k_10

Picnic_B C

Picnic_10



B.10 Option 11 – increased escape capacity to the Wakool River

To model increased diversions to the Wakool River, changes were made to the MSM

parameter file (Table B- 17) and the code in modflw20.f90 (Table B- 18).

The EDCAP variable in the MSM parameter file was changed because it includes the escape

capacity to the Wakool River, along with the escape capacities to the Edward River and

Yallakool River (Table B- 16).

Table B- 16: Calculating the change required to the EDCAP variable in the MSM parameter file to model Option 11

Base Case

Month May Jun Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr

Days 31 30 31 31 30 31 30 31 31 28 31 30

Edward Escape (ML/d)

2100 2400 2400 2400 2400 2400 2400 2400 2100 2100 2100 2100

Wakool Escape (ML/d)

550 550 550 550 550 550 550 550 550 550 550 550

Yallakool Escape (ML/d)

70 70 70 70 70 70 70 70 70 70 70 70

Total (ML/d) 2720 3020 3020 3020 3020 3020 3020 3020 2720 2720 2720 2720

Total (GL/month) 84.32 90.6 93.62 93.62 90.6 93.62 90.6 93.62 84.32 76.16 84.32 81.6

Option 11

Wakool Escape (ML/d) 1000 1000 1000 1000 1000 1000 1000 1000 1000 1000 1000 1000

Edward and Yallakool Escapes

As per Base Case

Total (ML/d) 3170 3470 3470 3470 3470 3470 3470 3470 3170 3170 3170 3170

Total (GL/month) 98.27 104.1

107.57

107.57 104.1

107.57 104.1

107.57 98.27 88.76 98.27 95.1

Table B- 17: Changes made to the MSM parameter file to model Option 11 – increased diversions to the Wakool River.


V551-MSM-TLM_Option1.txt 68 2 1-72 EDCAP1. CAPACITY OF EDWARD ESCAPE (May-Apr) A

84.32 90.6 93.62 93.62 90.6 93.62 90.6 93.62 84.32 76.16 84.32 81.6 68-2

73 7-12 EscapeNonUse - The capacity of the Edward Escapes in ML/d that is not called upon to prevent forest flooding that is not related to Hume-Lake Victoria transfers or meeting downstream demand (ie the capacity of the Yallakool and Wakool Escapes included in EDCAP)

10600. 620. 1000. 0.100 2 73


V551-MSM-TLM_Option11.txt 98.27 104.1 107.57 107.57 104.1 107.57 104.1 107.57 98.27 88.76 98.27 95.1 68-2

10600. 1070. 1000. 0.100 2 73



Table B- 18: Changes made to the modflow FORTRAN code to model Option 11 – increased diversions to the Wakool River.

FORTRAN file Original Code (beginning at line 1149)

modflw20.F90 ! If Edward Escape distribute excess Release to Wakool and Yallakool Escapes

if(EDWESC(RCHLCV))THEN

array4(daylcv,2)=max(0.,min(70.,day(daylcv)-uplim-550.))

array4(daylcv,1)=max(0.,min(550.,day(daylcv)-uplim))

totday(DAYLCV,NUM)=day(daylcv)-array4(daylcv,1) &

- array4(daylcv,2)

else

TOTDAY(DAYLCV,NUM) = DAY(DAYLCV)

endif

New Code (beginning at line 1149)

! If Edward Escape distribute excess Release to Wakool and Yallakool Escapes





- array4(daylcv,2)

else


endif

B.11 Option 12 – increased escape capacity to the Edward River

To model an increased escape capacity to the Edward River, changes were made to the MSM

parameter file (Table B- 20), the BigMod parameter file (Table B- 21) and the Modflow

parameter file (Table B- 22). Table B- 19 shows how changes to the values of EDCAP in the

MSM parameter file are calculated.



Table B- 19: Calculating the change required to the EDCAP variable in the MSM parameter file to model Option 12.

Base Case


Days 31 30 31 31 30 31 30 31 31 28 31 30

Edward Escape (ML/d)

2100 2400 2400 2400 2400 2400 2400 2400 2100 2100 2100 2100

Wakool Escape (ML/d)

550 550 550 550 550 550 550 550 550 550 550 550

Yallakool Escape (ML/d)

70 70 70 70 70 70 70 70 70 70 70 70

Total (ML/d) 2720 3020 3020 3020 3020 3020 3020 3020 2720 2720 2720 2720

Total (GL/month) 84.32 90.6 93.62 93.62 90.6 93.62 90.6 93.62 84.32 76.16 84.32 81.6

Option 12

Edward Escape (ML/d) 3200 3200 3200 3200 3200 3200 3200 3200 3200 3200 3200 3200

Wakool and Yallakool Escapes

As per Base Case

Total (ML/d) 3820 3820 3820 3820 3820 3820 3820 3820 3820 3820 3820 3820

Total (GL/month) 118.42 114.6 118.42 118.42 114.6 118.42 114.6 118.42 118.42 106.96 118.42 114.6

Table B- 20: Changes made to the MSM parameter file to model Option 12 – increased escape capacity to the Edward River.



84.32 90.6 93.62 93.62 90.6 93.62 90.6 93.62 84.32 76.16 84.32 81.6 68-2



Table B- 21: Changes made to the BigMod parameter file to model Option 12 – increased escape capacity to the Edward River.

Original Parameter File Control Variable Changed From

Changed To New File

V125-bigpar-prod_Option1.txt 402 (column 12) 5*2100.,7*2400. 5*3200.,7*3200. V125-bigpar-prod_Option12.txt

Table B- 22: Changes made to the Modflow parameter file to model Option 12 – increased escape capacity to the Edward River.

Original Parameter File Variable Changed From Changed To New File

V492b-Modflow-Param.txt EDWESC (column 2) 2100 3200 V492b-Modflow-Param.txt

EDWESC (column 3) 2400 3200



This option was run assuming the changes listed above. The modelling results indicated that

these changes would increase the volume of water passed through the Edward Escape during

the irrigation season. These increases would be both during times of rainfall-rejection (Figure

B- 12), and outside times of rainfall-rejection (Figure B- 13). Therefore, a decision needs to be

made on whether the extra Edward Escape capacity modelled in this option is used in the same

way as the current capacity, or is kept aside for the management of rainfall-rejections. Similar

decisions need to be made for Option 11, which is an increase in the capacity of the Wakool

Escape.

Figure B- 12: Modelled flows at Tocumwal and through the Edward escape under the base case (_BC), and Option 12 (_12). During rainfall-rejections in January and March 2001, extra water has been passed through the Edward escape.

Flo

w (

ML

/d)

0

2000

4000

6000

8000

10000

12000

14000

Jan01 Feb01 Mar01 A pr01 May01 Jun01

ED W ESC_B C

ED W ESC_12

T ocumw al_B C

T ocumw al_12



Figure B- 13: Modelled flows at Tocumwal and through the Edward escape under the base case (_BC), and Option 12 (_12). Although there is now rainfall rejection in March 2003, more water has been passed through the Edward escape under Option 12, compared with the base case.

B.12 Option 13 – increased escape capacity to Broken Creek

The modelling methodology for Option 13 is comprised of two steps (A and B). Step A is the

same as documented for the interconnector option (Option 15), which involves changing the

value of BROKEscOpt in the MSM parameter file from 1 (escape flows not added to

Yarrawonga diversions or flow at Rices Weir) to 3 (escape flows added to both), and then

factoring down the Yarrawonga diversions and Rices Weir inflow series until they match those

modelled in Option 1 (do nothing) (Table B- 23).

Changing the Rices Weir inflow series as part of Step A has been found to change the

BARMILL loss function (control variable 447, which is comprised partly of control variable

combination 29) in BigMod. This is because control variable combination 29 includes losses in

reach 168 (BROKEN CREEK - RICES WEIR TO MURRAY). Losses in reach 168 are

determined using control variable 619, which is „MSM reduction in Broken Ck Q‟. To undo

the observed change in BARMILL losses, the „LS‟ 168 component of control variable

combination 29 is removed in Step A (Table B- 24). This is based on the assumption that when

the BROKEscOpt in the MSM parameter file is 1 (Option 1), control variable 619 equates to 0.

Flo

w (

ML

/d)

0

2000

4000

6000

8000

10000

12000

14000

16000

N ov02 D ec02 Jan03 Feb03 Mar03 A pr03 May03

ED W ESC_B C

ED W ESC_12

T ocumw al_B C

T ocumw al_12



Step B involved increasing the values of BrokEscape on line 68-4 of the MSM parameter file,

so that 300 ML/d is passed down the Yarrawonga Main Channel to the Broken Creek escape

during every day of the unseasonal flooding period (January to April) (Table B- 25).

Table B- 23: Changes made to the MSM parameter file to model Option 13 – step A.


V551-MSM-TLM_Option1.txt ? 5 12 67-72 BROKEscOpt Option for handling Broken Creek Escape. ? 0=> No Escape flows and data not read in. ? >0 12 monthly values for Broken Creek Escape losses are input at Card 68-4 ? 1=> Escape Flows not added to Yarrawonga Gross or Rices Weir ? 2=> Escape Flows added to Yarrawonga Gross but not to Rices Weir ? 3=> Escape flows added to both Yarrawonga Gross and Rices Weir ? Note that Acoounting and Fixed diversion runs assume Option 2 ? because the Yarrawonga diversions input for those runs is net of ? yarrawonga and Broken Creek Escapes

40. 100. 50. 1. 0. 0.00 1 0. 0 0. 0 1 5-12

3 'Net Murray Valley Diversions' 9 0 0 198307 200006 0 199406 0.0 1.0 1.0667 0


V551-MSM-TLM_Option13StepA.txt 40. 100. 50. 1. 0. 0.00 1 0. 0 0. 0 3 5-12


Table B- 24: Changes made to the BigMod parameter file to model Option 13 – step A.

Original Parameter File Control Variable Combination (beginning at line 4552)

V125-bigpar-prod_Option1.txt 29 'Losses - Yarrawonga to Barmah' 8 '+' 'LS' 18 '+' 'LS' 19 '+' 'LS' 20 '+' 'LS' 128 '+' 'LS' 21 '+' 'LS' 168 '+' 'LS' 22 '+' 'LS' 23

New Parameter File New Control Variable Combination (beginning at line 4552)

V125-bigpar-prod_Option13StepA.txt 29 'Losses - Yarrawonga to Barmah' 7 '+' 'LS' 18 '+' 'LS' 19 '+' 'LS' 20 '+' 'LS' 128 '+' 'LS' 21 '+' 'LS' 22 '+' 'LS' 23

Table B- 25: Changes made to the MSM parameter file to model Option 13 – step B.


V551-MSM-TLM_Option1.txt ? 68 4 1-72 BrokEscape Broken Creek Escape (GL/mth) (May to Apr)

0.53 0.26 0.0 0.20 1.19 1.10 0.99 1.13 1.43 1.45 1.60 1.61 68-4


V551-MSM-TLM_Option13StepA.txt 0.53 0.26 0.0 0.20 1.19 1.10 0.99 1.13 9.3 8.4 9.3 9.0 68-4

As part of Step A, checks were made that flows in the system and the reliability of supply to

irrigators in Victoria and NSW are the same as for Option 1 (do nothing). Checks of the

preliminary runs show this to be the case (Figure B- 14 to Figure B- 16).



Figure B- 14: Comparison of irrigation allocations under Option 1 (do nothing) and

Option 13 – step A.

0

50

100

150

200

250

100 90 80 70 60 50 40 30 20 10 0

Vic

tori

an Ir

riga

tion

Allo

cati

on (%

)

Percent of Years Exceeded

Option 1

Option 13 - step A

0

20

40

60

80

100

120

100 90 80 70 60 50 40 30 20 10 0

NSW

Gen

eral

Sec

uirt

y Ir

riga

tion

Allo

cati

on (%

)


Option 1

Option 13 - step A



Figure B- 15: Comparison of average flows modelled by BigMod under Option 1 (do nothing) and Option 13 – step A



Figure B- 16: Comparison of average flows modelled by MSM under Option 1 (do nothing) and Option 13 – step A.



Results from a preliminary run of Step B show that under Option 13 the volume of water

passed through the Broken Creek escape would increase during the unseasonal flooding

period. These increases would be both during times of rainfall-rejection (Figure B- 17), and

outside times of rainfall-rejection (Figure B- 18). Therefore, a decision needs to be made on

whether the extra Broken Creek Escape capacity modelled in this option is kept aside for the

management of rainfall-rejections, or is also used to meet downstream demands.

Figure B- 17: Modelled flows downstream of Yarrawonga and from the Broken Creek to the River Murray under the base case (_BC), and Option 13 step B (_13). During rainfall-rejections in January and March 2001, extra water has been passed through the Broken Creek escape.

Flo

w (

ML

/d)

0

2000

4000

6000

8000

10000

12000

14000

Jan01 Feb01 Mar01 A pr01 May01 Jun01

Y A RRA D S_B C

Y A RRA D S_13

RI CES W R_B C

RI CES W R_13



Figure B- 18: Modelled flows downstream of Yarrawonga and from the Broken Creek to the River Murray under the base case (_BC), and Option 13 step B (_13). During periods of high demand, 10,600 ML/d is flowing down the River Murray in both scenarios, despite the extra water passing through the Broken Creek escape in Option 13.

B.13 Option 15 – Murray-Goulburn Interconnector channel

This option was modelled by increasing Murray Valley demand to represent the portion of

Shepparton Irrigation Area supplied from the River Murray, increase the Broken Creek Escape

to represent the direct bypass operation and increase Goulburn IVT account to represent the

flow substitution from the Goulburn River.

The flow delivered via Broken Creek and the Goulburn River will be in the pattern:

November: 5%

December: 25%

January: 25%

February: 25%

March: 20%

The total flow on average is 48GL/year via Broken Creek and 50GL/year via Goulburn River.

Flo

w (

ML

/d)

0

2000

4000

6000

8000

10000

12000

14000

D ec02 Jan03 Feb03 Mar03 A pr03 May03

Y A RRA D S_B C

Y A RRA D S_13

RI CES W R_B C

RI CES W R_13



The changes to MSM-Bigmod to simulate this option were undertaken in two steps. The first

step was based on the method developed for option 13 which set the Broken Creek Escape

Option to 3 which sets Escape flows to be added to both Yarrawonga Gross and Rices Weir.

This step involved changing the model to operate with BROKEscOpt set to 3 to replicate the

Do Nothing scenario as closely as possible (Step A) which is described in more detail below.

Then the model was adjusted in the following three ways:

increasing gross diversion to Yarrawonga Main Channel to simulate additional flow to the

interconnector channel;

including additional return flow from Broken Creek;

including additional IVT return from the Goulburn River.

Step A involved changing the value of BROKEscOpt in the MSM parameter file from 1

(escape flows not added to Yarrawonga diversions or flow at Rices Weir) to 3 (escape flows

added to both), and then factoring down the Yarrawonga diversions and Rices Weir inflow

series until they match those modelled in Option 1 (do nothing) (Table B- 26).

Changing the Rices Weir inflow series as part of Step A has been found to change the

BARMILL loss function (control variable 447, which is comprised partly of control variable

combination 29) in BigMod. This is because control variable combination 29 includes losses in

reach 168 (BROKEN CREEK - RICES WEIR TO MURRAY). Losses in reach 168 are

determined using control variable 619, which is „MSM reduction in Broken Ck Q‟. To undo

the observed change in BARMILL losses, the „LS‟ 168 component of control variable

combination 29 is removed in Step A (Table B- 27). This is based on the assumption that when

the BROKEscOpt in the MSM parameter file is 1 (Option 1), control variable 619 equates to 0.

Table B- 26: Changes made to the MSM parameter file to model Option 13 – step A.


V551-MSM-TLM_Option1.txt ? 5 12 67-72 BROKEscOpt Option for handling Broken Creek Escape. ? 0=> No Escape flows and data not read in. ? >0 12 monthly values for Broken Creek Escape losses are input at Card 68-4 ? 1=> Escape Flows not added to Yarrawonga Gross or Rices Weir ? 2=> Escape Flows added to Yarrawonga Gross but not to Rices Weir ? 3=> Escape flows added to both Yarrawonga Gross and Rices Weir ? Note that Accounting and Fixed diversion runs assume Option 2 ? because the Yarrawonga diversions input for those runs is net of ? yarrawonga and Broken Creek Escapes

40. 100. 50. 1. 0. 0.00 1 0. 0 0. 0 1 5-12



V551-MSM-TLM_Option13StepA.txt 40. 100. 50. 1. 0. 0.00 1 0. 0 0. 0 3 5-12




Table B- 27: Changes made to the BigMod parameter file to model Option 13 – step A.

Original Parameter File Control Variable Combination (beginning at line 4552)

V125-bigpar-prod_Option1.txt 29 'Losses - Yarrawonga to Barmah' 8 '+' 'LS' 18 '+' 'LS' 19 '+' 'LS' 20 '+' 'LS' 128 '+' 'LS' 21 '+' 'LS' 168 '+' 'LS' 22 '+' 'LS' 23

New Parameter File New Control Variable Combination (beginning at line 4552)

V125-bigpar-prod_Option13StepA.txt 29 'Losses - Yarrawonga to Barmah' 7 '+' 'LS' 18 '+' 'LS' 19 '+' 'LS' 20 '+' 'LS' 128 '+' 'LS' 21 '+' 'LS' 22 '+' 'LS' 23

As part of Step A, checks were made that flows in the system and the reliability of supply to

irrigators in Victoria and NSW are the same as for Option 1 (do nothing). Checks of the show

this to be the case (Figure B- 19 to Figure B- 21).

Figure B- 19: Comparison of irrigation allocations under Option 1 (do nothing) and

Option 13 – step A.

0

50

100

150

200

250

100 90 80 70 60 50 40 30 20 10 0

Vic

tori

an Ir

riga

tio

n A

lloca

tio

n (%

)


Option 1

Option 13 - step A

0

20

40

60

80

100

120

100 90 80 70 60 50 40 30 20 10 0

NSW

Gen

eral

Sec

uir

ty Ir

riga

tio

n A

lloca

tio

n (%

)


Option 1

Option 13 - step A



Figure B- 20: Comparison of average flows modelled by BigMod under Option 1 (do nothing) and Option 13 – step A



Figure B- 21: Comparison of average flows modelled by MSM under Option 1 (do nothing) and Option 13 – step A.



Increase diversions to Yarrawonga Channel

The supply to Murray Valley was increased by 50GL/year (increase Murray Valley HRWS by

50GL/year) in line 5-29

245.900 139.498 80.000 18.998 0 4 4 1 0 1 0.0 0.0 5-29

CHANGE TO:

295.900 139.498 80.000 18.998 0 4 4 1 0 1 0.0 0.0 5-29

Using trial and error the demand scaling factor (DEMSCALE) for Murray Valley was adjusted

until the gross diversion to Yarrawonga Main channel is approximately 98GL/year. (50GL/year in

supply to Murray Valley and 48GL/year in Broken Creek escape)

3 'Net Murray Valley Diversions' 9 0 0 198307 200006 0 199406 0.0 1.0

1.0405 0

CHANGE TO:

3 'Net Murray Valley Diversions' 9 0 0 198307 200006 0 199406 0.0 1.0

1.1700 0

The volume and pattern of Broken Creek Escape was changed as to represent the additional direct

bypass flow via Broken Creek, so line 68-4 was changed as shown below.

0.53 0.26 0.0 0.20 1.19 1.10 0.99 1.13 1.43 1.45 1.60 1.61 68-4

CHANGE TO:

0.53 0.26 0.0 0.20 1.19 1.10 3.39 13.13 13.43 13.45 11.20 1.61 68-4

Additional IVT flow on the Goulburn River of 50GL/year was included, so line 92 was changed as

shown below.

? 92 1-8 EVA-Entitlement(1,1)-Goulburn High Reliability WS End of Valley Account

IVT Entitlement

109.418 0. 9999. 9999. 9999. 0. 0. 9999. 9999. 9999. 92

CHANGE TO:

159.418 0. 9999. 9999. 9999. 0. 0. 9999. 9999. 9999. 92



B.14 Option 16 – Perricoota Escape

To model diversions through the Perricoota Escape, changes are made to the MSM parameter file

(Table B- 29), the code in modflw20.f90 (Table B- 30) and the BigMod parameter file (Table B-

31).

The EDCAP variable in the MSM parameter file are modified to include the Perricoota Escape

capacity (Table B- 28), along with the escape capacities to the Edward River, Wakool River and

Yallakool River. This means the Perricoota Escape will behave in the same way as the Wakool and

Yallakool Escapes.

Table B- 28: Calculating the change required to the EDCAP variable in the MSM parameter file to model Option 16 – Perricoota Escape

Base Case


Days 31 30 31 31 30 31 30 31 31 28 31 30

Edward Escape (ML/d) 2100 2400 2400 2400 2400 2400 2400 2400 2100 2100 2100 2100

Wakool Escape (ML/d) 550 550 550 550 550 550 550 550 550 550 550 550

Yallakool Escape (ML/d) 70 70 70 70 70 70 70 70 70 70 70 70

Total (ML/d) 2720 3020 3020 3020 3020 3020 3020 3020 2720 2720 2720 2720

Total (GL/month) 84.32 90.6 93.62 93.62 90.6 93.62 90.6 93.62 84.32 76.16 84.32 81.6

Option 11

Edward Escape (ML/d) As per Base Case

Wakool Escape (ML/d) As per Base Case

Yallakool Escape (ML/d) As per Base Case

Perricoota Escape (ML/d) 200 200 200 200 200 200 200 200 200 200 200 200

Total (ML/d) 2920 3220 3220 3220 3220 3220 3220 3220 2920 2920 2920 2920

Total (GL/month) 90.52 96.6 99.82 99.82 96.6 99.82 96.6 99.82 90.52 81.76 90.52 87.6

Table B- 29: Changes made to the MSM parameter file to model Option 16 – Perricoota Escape



84.32 90.6 93.62 93.62 90.6 93.62 90.6 93.62 84.32 76.16 84.32 81.6 68-2

73 7-12 EscapeNonUse - The capacity of the Edward Escapes in ML/d that is not called upon to prevent forest flooding that is not related to Hume-Lake Victoria transfers or meeting downstream demand (ie the capacity of the Yallakool and Wakool Escapes included in EDCAP)

10600. 620. 1000. 0.100 2 73



10600. 820. 1000. 0.100 2 73



The modflow code was modified to include the Perricoota Escape, which used after the capacity of

the Wakool and Yallakool Escapes are exceeded.

Table B- 30: Changes made to the modflow FORTRAN code to model Option 16 – Perricoota escape.

Original Code (beginning at line 220)

real array1(31,80),array2(31,60), &

array3(31,103),array4(31,2) ! Array 4 is where Wakesc and Yallesc are stored

real array1Previous(31,80),array2Previous(31,60), &

array3Previous(31,103),array4Previous(31,2) ! Storage of daily values for previous month

Option 16 Code (beginning at line 220)

real array1(31,80),array2(31,60), &

array3(31,103),array4(31,3) ! Array 4 is where Wakesc, Yallesc, Perresc are stored

real array1Previous(31,80),array2Previous(31,60), &

array3Previous(31,103),array4Previous(31,3) ! Storage of daily values for previous month

Original Code (line 231)

data array4/62*0./

Option 16 Code (line 231)

data array4/93*0./


WRITE (17, '(I2)') No_Firstfile+8 ! 11 for WEIR32,CAW2DAR,

! Ovens,Kiewa, Murrumbidgee,Darlot,ymcesc,Cawnout, Tandiv, WAKESC,

! YALLESC, MCCOYSB+IVT, BALRAN+IVT variables


WRITE (17, '(I2)') No_Firstfile+9 ! 11 for WEIR32,CAW2DAR,

! Ovens,Kiewa, Murrumbidgee,Darlot,ymcesc,Cawnout, Tandiv, WAKESC,

! YALLESC, MCCOYSB+IVT, BALRAN+IVT, PERRESC variables

Additional Code for Option 16 (beginning at line 665)

call u_writecsvhead(ic1,icsv+9,precision, &

ninterp,endmth,'PERRESC',204,'1','PERRESC', &

'PERRESC-204 output from MSM',err)


HEAD3 = HEAD3(1:HEAD3END) // ',' // 'WEIR32'//','// &

'CAW2DAR'//','//'CAWNOUT'//','// &

'TANDIV'//','//'WAKESC'//','//'YALLESC'//','// &

'MCCOYSB'//','//'BALRAN'


HEAD3 = HEAD3(1:HEAD3END) // ',' // 'WEIR32'//','// &

'CAW2DAR'//','//'CAWNOUT'//','// &

'TANDIV'//','//'WAKESC'//','//'YALLESC'//','// &

'MCCOYSB'//','//'BALRAN'//','//'PERRESC'


DO DAYLCV = 1, NUMDAYS

!








- array4(daylcv,2)

else


endif

ENDDO


DO DAYLCV = 1, NUMDAYS

!





array4(daylcv,3)=max(0.,min(200.,day(daylcv)-uplim-550.-70.))


- array4(daylcv,2) - array4(daylcv,3)

else


endif

ENDDO

ENDDO


do i = 1, 2

array4Previous (DAYLCV, i) = array4 (DAYLCV, i)

end do


do i = 1, 3

array4Previous (DAYLCV, i) = array4 (DAYLCV, i)

end do


! Write to Daily flow file for BIGMOD

!

WRITE(17,'(2(I2,A1),I4,33(A1,F11.1))') DAYLCV, COMMA, MonthPrevious, COMMA, YearPrevious, &

(COMMA,TotDayPrevious(DAYLCV,LCV),LCV=1,No_firstfile),comma, &

array1Previous(daylcv,Col_w32), comma, array1Previous(daylcv,Col_Caw2dar), comma, &

array1Previous(daylcv,Col_Cawnout), comma, array1Previous(daylcv,Col_tandou),comma, &

array4Previous(daylcv,1), comma, array4Previous(daylcv,2), comma, &

array3Previous(daylcv,Col_McCoysB), comma, array3Previous(daylcv,Col_Balran)


! Write to Daily flow file for BIGMOD

!

WRITE(17,'(2(I2,A1),I4,33(A1,F11.1))') DAYLCV, COMMA, MonthPrevious, COMMA, YearPrevious, &

(COMMA,TotDayPrevious(DAYLCV,LCV),LCV=1,No_firstfile),comma, &

array1Previous(daylcv,Col_w32), comma, array1Previous(daylcv,Col_Caw2dar), comma, &

array1Previous(daylcv,Col_Cawnout), comma, array1Previous(daylcv,Col_tandou),comma, &

array4Previous(daylcv,1), comma, array4Previous(daylcv,2), comma, &

array3Previous(daylcv,Col_McCoysB), comma, array3Previous(daylcv,Col_Balran), comma, &

array4Previous(daylcv,3)



The BigMod parameter file was modified to include a new branch from the Mulwala Canal (at the

Edward Escape) to the River Murray at the Wakool Junction. The branch cannot be modelled as

joining the River Murray at Torrumbarry, because for the purposes of modelling, BigMod

considers Torrumbarry to be upstream of the Mulwala Canal (at the Edward Escape).

The changes required to BigMod are:

Increase the number of reaches from 235 to 236;

Increase the number of reaches for which there is definition data from 225 to 226;

Increase the number of branches from 87 to 88.

Increase the number of inputs from modflow („BIGINFLOW2‟) from 18 to 19;

Add the reach, reach definition and branch data as per Table B- 31.

Table B- 31: Changes made to the BigMod parameter file to model Option 16 – Perricoota Escape.

New BigMod Reach Data – Option 16

? 1. = REACH NUMBER

? 2. IDSRCH = DOWNSTREAM REACH NUMBER (ALL OUTFLOW FROM REACH ENTERS HERE)

? 3. IRACT = IS REACH ACTIVE ? (1=YES)

? 4. IRSAL = ARE CONCENTRATIONS CALCULATED FOR REACH (1=YES)

? 5. RCHLEN = LENGTH OF REACH IN KM

? 6. RUSCHN = U/S CHAINAGE DISTANCE FROM RIVER MOUTH IN KM

? 7. TITRCH = TITLE FOR REACH (MAX 50 CHS)

?

? NOTE: The reaches below must be in stream order. That is, no reach must

? have as its downstream reach one that is above it on the list.

? However, the reach numbers do not have to be in numerical order.

?

? ----------------------------------------------------------------------------

? 1 2 3 4 5 6 7

300 76 1 1 60. 0. 'PERRICOOTA ESCAPE - EDW ESCAPE TO TORRUMBARRY'

New BigMod Reach Definition – Option 16

? 1 2

? 2 3 4 5 6 7 8 9 10 (11-20)

? ----------------------------------------------------------------------

? # TITRCH

? DS IEVAST1 IEVAST2 IRCHDV1 IRCHDV2 RDVFAC1 RDVFAC2 EXLSCV EXLSFAC (RCHLOD,RCHINI=1,NWQPD)

? F1 F2 F3 F4 F5 F6 F7 F8 F9 F10 (ML/D)

? TT1 TT2 TT3 TT4 TT5 TT6 TT7 TT8 TT9 TT10 (DAYS)

? AR1 AR2 AR3 AR4 AR5 AR6 AR7 AR8 AR9 AR10 (HA)

? HL1 HL2 HL3 HL4 HL5 HL6 HL7 HL8 HL9 HL10 (ML/D)

? RLJ RLF RLM RLA RLM RLJ RLJ RLA RLS RLO RLN RLD (ML/D)

?

? WHERE :

? # = REACH NUMBER

? DS = DEAD STORAGE IN REACH (ML)

? IEVAST1 = THE FIRST EVAPORATION STATION APPLIED TO THIS REACH

? IEVAST2 = THE SECOND EVAPORATION STATION APPLIED TO THIS REACH

? (Where evaporation and rainfall are read in separately,

? Ievast1 may be evaporation multiplied by a pan factor and

? Ievast2 may be rainfall multiplied by -1)

? IRCHDV1 = THE FIRST MONTHLY DIVERSION FIELD APPLIED TO THIS REACH

? IRCHDV2 = THE SECOND MONTHLY DIVERSION FIELD APPLIED TO THIS REACH

? RDVFAC1 = THE FRACTION OF DIVERSION FIELD 1 REMOVED FROM REACH

? RDVFAC2 = THE FRACTION OF DIVERSION FIELD 2 REMOVED FROM REACH

? GWLSCV = The Control Variable Number defining extra loss from Reach



? GWLSFAC = The Fraction of the Loss that applies in this reach

?

? -----------THE FOLLOWING DATA ONLY REQUIRED WHEN nwqpd > 0 -------------

? IRCVLD(1)= THE CONTROL VARIABLE DEFINING THE LOAD OF WQ PARAMETER 1

? ENTERING REACH

? RCHLOD(1)= THE FRACTION OF CONTROL VARIABLE IRCVLD(1) ENTERING REACH

? IRCVLD(2)= THE CONTROL VARIABLE DEFINING THE LOAD OF WQ PARAMETER 2

? ENTERING REACH

? RCHLOD(2)= THE FRACTION OF CONTROL VARIABLE IRCVLD(2) ENTERING REACH

? etc for nwqpd sets of load and initial concentration

? ------------------- NEW LINE--------------------------------------

? F1 = FIRST FLOW (ML/D)

? TT1 = TRAVEL TIME FOR FLOW 1 (DAYS)

? AR1 = SURFACE AREA AT FLOW 1 (HECTARES)

? HL1 = HIGH FLOW LOSS FOR FLOW 1 (ML/D)

? F2 = SECOND FLOW ETC.

?

? REACH 300 - PERRICOOTA ESCAPE - EDWARD ESCAPE TO TORRUMBARRY WEIR POOL

300 'PERRICOOTA ESCAPE - EDW ESCAPE TO TORRUMBARRY'

0. 5 4 1 2 0.000 0.000 0 0.000 34 0.000

0. 50. 500. 1000. 2000. 5000. 10000. 15000. 25000. 100000.

1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0

0. 75. 75. 75. 75. 75. 75. 75. 75. 75.

0. 0. 0. 0. 0. 0. 0. 0. 0. 0.

12*0.

New BigMod Branch – Option 16

? 1. IBRNRF = BRANCH NUMBER

? 2. TITBRN = TITLE OF BRANCH

? 3. IBRNCH(1) = REACH FROM WHICH BRANCH SPLITS

? 4. FRCBRN = LOCATION IN REACH FROM WHICH BRANCH SPLITS(0.=U/S,1.=D/S)

? 5. IBRNCH(2) = REACH NUMBER OF BRANCH

? 6. IFILBR = THE NUMBER OF THE INPUT FLOW FILE CONTAINING BRANCH FLOW

? 7. IBRPOS = POSITION OF BRANCH FLOW ON INPUT FLOW FILE "IFILBR"

? (0 IF FLOW NOT READ IN) - IF PRESENT DATA FROM THE INPUT FILE

? OVER-RIDES ANY OTHER DEFINITION OF BRANCH FLOW

? 8. IBRCV = REFERENCE NO. OF CONTROL VARIABLE USED WITH BRANCH FLOW TABLE

? 9. IOVREG = NUMBER OF REGULATOR WHICH MODIFIES BRANCH FLOW RELATIONSHIP

? +ve numbers specify regulators : 0 specifies no regulator

? HOWEVER IF IOVFLD > 1 AND IBRCVO > 0 then:

? 0 => Maximum of tabulated flow and order

? -1 => Minimum of tabulated flow and order

? -2 => Two tables read. Branch = max(table1,min(order,table2))

? 10. IOVSUB = IS CALCULATED BRANCH FLOW REDUCED BY EXISTING FLOW IN D/S

? REACH (0=NO,1=YES)

? IF IOVSUB = -1 THEN NO ERROR MESSAGE IS OUTPUT WHEN BRANCH

? FLOW EXCEEDS FLOW IN REACH (IT IS HOWEVER TRUNCATED)

? 11. IOVFLD = NUMBER OF FIELDS IN THE TABLE DEFINING THE RELATIONSHIP

? BETWEEN THE CONTROL VARIABLE AND THE BRANCH FLOW (Max 25)

? Note: If IOVFLD = 0 the branch flow = the value of

? the control variable

? 12. IBRCVO = REFERENCE NO. FOR CONTROL VARIABLE WHICH SPECIFIES

? DOWNSTREAM ORDER AT BRANCH. FLOW IS SET AT MAXIMUM OF VALUE

? CALCULATED FROM TABLE AND THE DOWNSTREAM ORDER.

? /

? 13+ FOVER = TABLE CONTAINING IOVFLD SETS OF THREE VALUES WHICH DEFINE

? THE RELATIONSHIP BETWEEN FLOW IN THE MAIN REACH AND FLOW

? IN THE BRANCH.

?

? Line 1. FLOWS IN MAIN REACH

? Line 2. CORRESPONDING FLOW IN BRANCH WHEN REGULATOR CLOSED

? Line 3. CORRESPONDING FLOW IN BRANCH WHEN REGULATOR OPEN

? Note: When IOVREG = 0 or -1, only lines 1 and 2 will be read

?

? 1 2 3 4 5 6 7 8 9 10 11 12

? ---------------------------------------------------------------------------

150 'TO PERRICOOTA ESCAPE' 50 1.000 300 2 19 0 0 0 0 0



B.15 Option 17 – combined weir manipulation

The proposed modelling methodology for Option 17 is the same as adopted for modelling of

Euston Weir (Appendix B.7).

This involved using the MSM-Bigmod output from the „do-nothing‟ option in combination with the

shortfall indicator which includes the ability to draw on the active volume and order replenishment

flow to refill the multiple weir pools when channel capacity is available.






Component


ve or –

ve)












Stoney inflows - 9 Modelled inflows from Bigmod


Balranald inflows - 11 Modelled inflows from Bigmod








Component


ve or –

ve)






NSW control or otherwise the sum of the release capacity from Wetherell, Pamamaroo and Menindee less

loss from Weir 32 to Burtundy.

This calculation of required flow can be readily adapted to include the ability to temporarily

drawdown the weirs to meet peak demands.

To simulate the drawdown of the weirs to meet peak demands and avoid shortfalls in the indicator

the daily shortfall volume was reduced by the volume of drawdown available in the weirs,

restricted by the required flow at Wentworth (14 days in advance) and a maximum allowable rate

of drawdown (if applicable).

The weirs were assumed to be rapidly drawn down from the start of the shortfall event, and refilled

as soon as spare capacity for transfers becomes available. It was assumed that there was no

constraint in terms of a maximum allowable rate of refill.

The weirs, drawdowns and available air space are outlined in Table B- 33.

Table B- 33: Combined weir option drawdown

Weir Drawdown (m) Airspace Created (ML)

Torrumbarry (Lock 26) 0.40 3055

Euston (Lock 15) 0.30 3990

Mildura (Lock 11) 0.25 2780

Wentworth (Lock 10) 0.25 3490

Kulnine (Lock 9) 0.20 2954

Wangumma (Lock 8) 0.50 2927

TOTAL - 19196



Appendix C Calculation of the significance of the problem

A key task of the Investigation Phase of the Barmah Choke Study (SKM, 2009) was to develop

indicators relating to the overall Barmah Choke Study objectives. These indicators can be used to

assess and compare options and establish a base case (Option 1- do nothing) against which all other

options can be compared. The development and calculation of each of the indicators developed as a

part of the Investigation Phase is detailed in Section C.1 to C.4.

In addition to the Barmah Choke Study specific indicators, the MDBA generally produces a set of

standard hydrological indicators for all runs. These indicators are used by the MDBA to enable a

quick overview and initial assessment of scenario runs (MDBA, 2010a). These can also be used to

assess and compare options and establish a base case. The MDBA standard hydrological indicators

that will be used for the Barmah Choke Study are listed in Section C.5.

All of the indicators discussed in this Appendix (MDBA standard indicators and Barmah Choke

Study specific indicators) have been used to assess and compare options for the Individual Options

Phase of the Barmah Choke Study. The tables and figures that are presented in this Appendix are

designed to be examples of what can be found in the following Appendices. They are example

plots or tables with no results.

C.1 Shortfalls and rationing of diversions

Each year in the River Murray System, an allocation is announced for both NSW and Victoria at

the start of the season. The allocation is dependent on each State‟s available resources and is

updated during the season. Irrigation and other demands are then restricted based on the announced

allocation. A shortfall occurs when the restricted demand cannot be supplied due to channel

capacity constraints or a lack of resource storage in the lower system.

Channel capacity constraints occur at two main points in the River Murray System: downstream of

Hume Reservoir and at the Barmah Choke, however the Barmah Choke is the key constraint. The

channel operating capacity of Hume Reservoir is restricted to 25,000 ML/day. The channel

operating capacity of the Barmah Choke is 8,000 ML/day measured at Barmah, which equates to

10,600 ML/day downstream of Yarrawonga Weir.

To assess the significance of the problem under the base case, and to determine the impact of

options on the significance of the problem, the number of years with shortfalls is calculated.

Shortfalls are calculated on a monthly time-step by MSM; if the demand for a given month is in

excess of available channel capacity a shortfall is recorded. Calculating shortfalls on a monthly

time-step is inadequate for the purposes of the Barmah Choke Study as shortfalls occurring over



short time periods are not identified. Daily shortfalls are not calculated directly by Bigmod as the

demands passed to Bigmod from MSM have already been restricted based on monthly channel

capacity.

To assess the incidence and magnitude of shortfalls for the Barmah Choke Study, a method was

developed to determine required flow at downstream Hume Reservoir and downstream

Yarrawonga Weir based on model outputs. Required flow was then compared to operational

channel capacity. The method for determining required flow was developed based on the methods

used by the river operators to determine the required releases from Hume Reservoir and

Yarrawonga Weir.

Table C- 1and Table C- 2 outline the method and components used to calculate required flow at

downstream Yarrawonga Weir and downstream Hume Reservoir respectively. The volume of

required flow was then compared to the operational capacity of 10,600 ML/day (downstream

Yarrawonga Weir) and 25,000 ML/day (downstream Hume Reservoir) to estimate the timing and

volume of shortfall events.

Table C- 1: Calculation of required flow at downstream Yarrawonga Weir.

Component Contribution to Flow at

Yarrawonga (+

ve or –

ve)

Lag (days in

advance)

Model Component Used

Edward Offtake + 3 Modelled Edward offtake flows from Bigmod

Gulpa Offtake + 3 Modelled Gulpa offtake flows from Bigmod

Broken Creek Inflows - 4 Modelled inflows from Bigmod

Goulburn River Inflows - 4 Modelled inflows from Bigmod

National Channel Orders + 6 National Channel Diversions from Bigmod

Loss Yarrawonga - Torrumbarry


Pental Island Orders + 9 Pental Island pumps diversions from Bigmod.


Stoney inflow - 9 Modelled inflows from Bigmod

Swan Hill Orders + 10 Calculated as 0.745 times Channel 9 diversions (from Bigmod)

Balranald Inflow - 11 Modelled inflows from Bigmod



Loss Wakool Junction to Euston





Yarrawonga (+

ve or –

ve)

Lag (days in

advance)






NSW control or otherwise the sum of the release capacity from Wetherell, Pamamarro and Menindee less

loss from Weir 32 to Burtundy.

Table C- 2: Calculation of required flow at downstream Hume Reservoir.


Hume

(+ve

or –ve

)

Lag (days in

advance)


Wangaratta Flow - 1 Modelled inflows from Bigmod

Mulwala Canal Order + 2 Modelled demands from Bigmod

Yarrawonga Main

Channel Order

+ 2 Modelled demands from Bigmod

Loss Doctors Point to

Yarrawonga

+ 3 Loss (evap loss + short evap) for Doctors Point to

Yarrawonga, plus monthly Doctors Point to

Yarrawonga PD demands (restricted for channel

capacity) all from MSM. Disaggregated based on a

calibrated daily pattern from PRIDE.

Required flow at

downstream Yarrawonga

Weir

+ 3 Calculated as per Table C- 1

The resulting shortfalls from the above calculations can be classified by two ways: by the extent to

which operators may be able to manage (avoid) the event and by the type (or cause) of the event.

For the purposes of the Barmah Choke Study manageability was based on the average magnitude

(volume per day) and duration of the event, with manageability thresholds based on advice from



MDBA river operators. Other factors also contribute to the manageability of a shortfall event such

event timing and peak magnitude.

Shortfalls of short duration and low magnitude are classified as expected to be manageable.

Shortfalls of either short duration or low magnitude are classified as challenging to manage.

Shortfalls of long duration and high magnitude are classified as more difficult to manage.

There is generally considered to be two broad types (related to cause) of shortfalls. The first type

(type I) is peak demand shortfalls. Peak demand shortfalls are typically short duration events in the

mid-reaches of the river between Barmah Choke and the Darling River of Lake Victoria due to

insufficient channel capacity to meet peak irrigation demands. This type of shortfall event is more

likely to be classified as manageable, however the average magnitude of such an event can be very

large, which may make the event challenging to manage.

This type of event may lead to outcomes such as rationing of demands in Torrumbarry and

Sunraysia. To manage this type of shortfall event, options focused on enabling rapid, short-term

responses may be appropriate. This includes mid-river storage options and policy options which

increase operational flexibility.

The second type (type II) of shortfalls is lower system storage shortfalls. Lower system storage

shortfalls are typically long in duration affecting the whole River Murray System downstream of

the Barmah Choke (through to South Australia) due to limited resources in Lake Victoria and the

Menindee Lakes (and insufficient channel capacity to implement bulk transfers to Lake Victoria).

This type of shortfall event is more likely to be classified as challenging or more difficult to

manage due to the typically long duration of the event. These events also tend to have a large

average magnitude.

This type of event may lead to outcomes such as rationing of demands along the entire River

Murray System downstream of the Barmah Choke including supply to South Australia. To manage

this type of event, options focused on enabling long-term increased flexibility may be appropriate.

This includes options to enhance existing bypass capacity and policy options such as modifying the

Hume to Lake Victoria transfer rules.

The final indicator matrix, which summarises total shortfalls as well as shortfall manageability and

shortfall type, is shown in Table C- 3.



Table C- 3: Shortfalls based on flow downstream of Yarrawonga Weir.

Duration Average Magnitude (ML/day) Total by Duration

< 1,000 ML/day 1,001 –

1,500 ML/day

> 1,500 ML/day

1 – 5 days

6 – 10 days

11 – 15 days

> 15 days

Total by magnitude


Number (total)

Number (type I- peak demand)

Number (type II- lower system storage)

Average volume (GL)

Average duration (days)


Number



Average volume (GL)



Number



Average volume (GL)


Total shortfalls Number (total)



C.2 Unseasonal flooding

Flows which exceed the capacity of the Barmah Choke lead to flooding of the Barmah-Millewa

Forest. The existence and health of the forest is heavily dependent on the presence of the Barmah

Choke. Whilst flooding during winter and spring is typically beneficial to the health of the forest,

unseasonal flooding (defined as flooding which occurs between December 15 and April 30

(MDBC, 2006)) can be detrimental to the health of the forest.

The natural watering regime of the Barmah-Millewa Forest saw large-volume, long-duration floods

occurring most commonly over the winter and spring period between August and November, with

a drying period over the summer months. Regulation of the River Murray System has significantly

altered the natural watering regime. River regulation has lead to a reduction in the frequency,

extent and duration of beneficial winter and spring flooding and an increase in summer flooding.

The flooding events that do occur under current conditions also tend to be shorter in duration with a

lower peak flood magnitude.

The alteration of the natural watering regime is considered to be leading to changes in the

ecological character of the forest, altering the mix and health of vegetation communities and



reducing biodiversity. In particular, the reduction in beneficial winter and spring flooding is leading

to vegetation stress (particularly in the recent dry years) and is significantly affecting species

dependent on the health of the forest and winter/spring flooding (such as colonial water birds). The

increase in summer flooding is lead to the expansion of areas of River Red Gum and Giant Rush

into areas formerly covered by Moria Grass plains (such as War Plain, Steamer Plain and the

central forest plains). Other costs of the increase in summer flooding are also noted, including loss

of water and the impact of access to, and use of, the Barmah-Millewa Forest.

To assess the significance of the problem under the base case, and to determine the impact of

options on the significance of the problem, the number of years where flow exceeds the capacity of

the Barmah Choke (measured downstream of Yarrawonga Weir) is calculated

To assess unseasonal flooding a (detailed) matrix was developed which counted the number of

unseasonal flooding events by timing (month), magnitude and duration. The event magnitude was

equal to the maximum flow during the event. The event length was defined as the number of days

flow was above 10,600 ML/day (measured at downstream Yarrawonga) including any subsequent

spikes which occurred less than 7 days following the initial event. The month that the event

occurred in was defined as the month in which the peak flow occurred.

The final indicator for unseasonal flooding forms a (summary) matrix which counts the number of

years in which undesirable events occur and categorises them according to magnitude and duration.

If there is more than one unseasonal flooding event in a year then only the most sever event

(defined by magnitude) is reported.

The unseasonal flooding period is defined as between 15th December and 30

th April (MDBC,

2006). However, in MSM-Bigmod, channel capacity downstream of Yarrawonga Weir is set on a

monthly basis, resetting on the first of each month. Therefore, for modelling purposes, the

unseasonal flooding period has been defined as between 1st January and 30

th April.

It takes time for the model to reset maximum flow for the Barmah Choke capacity in December to

the Barmah Choke capacity in January. For the first few days in January flow may exceed the

capacity of the Barmah Choke as the model is adjusting. These modelling anomalies were not

counted as undesirable floods.

To ensure that beneficial events were not counted as undesirable flooding and that single events

were not double counted, the following adjustments were also made:

Flows which represent the tail end or start of a beneficial flood event were excluded from the

period of analysis, recognising that undesirable flooding which extends beneficial floods can

be beneficial.



Flow spikes which occurred up to 7 days after (or before) a beneficial event were excluded

from the period of analysis, as flood events less than or equal to 7 days apart were not

considered independent.

From the total number of years of unseasonal flooding, three useful indicators are considered:

the number of years of moderate flooding

the number of years of more severe flooding

proportion of wet years for each side of the forest

The calculation of the number of years of moderate or more severe flooding are based on key

vegetation thresholds. The critical flow threshold at which Moira Grass plains begin to be

significantly impact is estimated to be 11,000 ML/day. Flows between 11,000 ML/day and

15,000 ML/day significantly affect Moira Grass, while flows greater than 15,000 ML/day also

affect River Red Gums. Based on these thresholds, years with unseasonal flooding events which

peak between 11,000 ML/day and 15,000 ML/day are classified as years of moderate flooding

while years with unseasonal flooding events which peak high than 15,000 ML/day are classified as

years of more severe flooding.

The calculation of the proportion of wet years for each side of the forest is based on key regulation

thresholds. For flood events which peak below 15,000 ML/day forest regulators can be used to

control flooding to one side of the forest. Such events are shared alternately between the Barmah

Forest (Victoria) and the Millewa Forest (NSW) on an annual basis. For flood events which peak

between 15,000 ML/day and 18,000 ML/day regulators can be used to maintain some control over

flows, however it is expected that both sides of the forest will be flooded. For flood events which

peak higher than 18,000 ML/day all regulators are opened and extensive flooding would be

expected on both sides of the forest. Based on these thresholds, the proportion of wet years for each

side of the forest was defined as:

𝑃𝑟𝑜𝑝𝑜𝑟𝑡𝑖𝑜𝑛 𝑜𝑓 𝑤𝑒𝑡 𝑦𝑒𝑎𝑟𝑠 =

𝑌𝑒𝑎𝑟𝑠 𝑓𝑙𝑜𝑤 > 11,000 & < 15,0002 + 𝑌𝑒𝑎𝑟𝑠 𝑓𝑙𝑜𝑤 > 15,000

𝑁𝑜 𝑜𝑓 𝑌𝑒𝑎𝑟𝑠

The final unseasonal flooding indicator is shown in Table C- 4.



Table C- 4: Unseasonal flooding of the Barmah-Millewa Forest.


Duration 10,601 –

11,000

11,001 –

13,000

13,001 –

15,000

15,001 –

18,000

>18,000

0-2 days

3-7 days

>7 days

Total by Flow

Total years of unseasonal flooding

Total years of moderate unseasonal flooding

Total years of more severe unseasonal flooding

Proportion of wet years for each side of the forest

C.3 Quantifying change to Barmah Forest watering

An important indicator of option performance is the reduction in the number of years each side of

the Barmah-Millewa Forest experiences undesirable flooding. This section provides additional

detail relating to the evaluation of options in terms of their impact on the ecology of the Barmah-

Millewa Forest.

Changes to Barmah forest watering

Evaluations are often made by comparing the forest under some scenario with what it would have

been like under „natural‟ conditions. For this area there is the question of what is the „natural‟

forest? Traditionally, „natural‟ would be defined as the forest as found by Europeans and formed by

flooding typified in data prior to 1934, which represents pre-Hume Dam operation. However there

has been over seventy years of river management since then and many areas of the forest have

„moved‟ towards a new hydro-ecological state that reflects such changes. Typically these will be

most marked at the wetter end of the spectrum (the drier end of the spectrum does not have the

„biological energy‟ necessary to make rapid changes). We propose that all assessments present

information in terms of deviation from the „existing condition‟ as defined by Option 1.

Quantifying change

The potential influences of the different options on the Barmah-Millewa Forest are diverse but the

most relevant and detectable changes are found in the flow hydrographs in the December to March

period. These flow hydrographs are an output of option modelling.

In this period there is a conscious attempt by river operators to manage flow to keep it at or close to

the limit of channel capacity of the Barmah Choke. Flow deviations above this limit lead to

incursions of water into the forests on either side of the river. The exact penetration of these will

depend on many factors including the setting of regulators, the rate of rise of the river, and the

magnitude of river flows. However forest flooding as a function of river flow is predictable and

consistent along the length of the River Murray through the Barmah-Millewa forest.



For flows above channel capacity (10,600 ML/d downstream Yarrawonga) water that “spills” into

the forest carries with it a number of consequences. First in comparison with the pre-regulation

period (as defined by the „modelled natural‟ case), there would be few occasions when any such

flooding occurred during this December to March period. Thus, from this point of view such

summertime water penetration is undesirable.

However, the forest ecosystem has already been modified by seventy years of occasional water

penetration so the forest ecology is likely to have adjusted to these conditions to some extent.

In general, the flows that exceed the capacity of the Barmah Choke in this period are not very large

by River Murray flood standards. This means that they do not penetrate far into the forest. Further,

their penetration is usually into areas that have frequently had such flows in the past (since

regulation began). Thus some of the adverse effects on ecosystems in those areas frequently

flooded may have already occurred.

Changes caused by undesirable flooding can be viewed as having an initial impact and an ongoing

influence. Examples include:

Death of red gum trees or small stands of trees in the lowest areas of the forest. This was

reported soon after river regulation was made possible by the construction of Hume Dam.

Although major changes in flow associated with new works or management regimes may

cause this again, most areas that would be very susceptible have already changed. In general,

visible evidence of such change was removed many decades ago (Figure C- 1).

Changes in various ecosystems in complex ways. The most expected or visible would include

favouring of red gum over grass on grass plains (e.g. Bren et al., 1987; Bren, 2005), and

favouring of reeds or rushes over grass plains. There would also be changes in the flora and

fauna of ponds and effluent channels in the river. This would be expected to encompass

species at all levels, from bacterial slimes (e.g. Robertson et al. 2000), to macrophytes, to fish

species. However, as in the above case it is likely that such changes may have already occurred

i.e. the on-going influence of undesirable flooding is small compared to the initial impact.

Alterations to forest access for forest workers and managers, river operation workers and

visitors. The major access roads tend to be constructed on „high ground‟ or have bridges or

other works allowing traffic movement. However, minor roads become „cut‟ by flowing water,

which can decrease the amenity of the forest for visitors and impose costs on forest managers.

„Black water events‟: In these, water enters the forest and re-emerges into the main channel.

The water achieves a loading of tannins and other polyphenolics and organic compounds from

the forest litter. This removes oxygen from the water. The result can be fish kills and emersion

of aquatic species that can survive outside the water for short periods. Howitt et. al., (2005,

2007) show that „pooled floods‟ at the warmest months of the year are substantially more

likely to result in blackwater events.



Occasional bird-breeding episodes. Late recession of spring floods plus other small floods can

lead to delayed bird-breeding events. These can be positive but also present a management

dilemma as they present the choice of withdrawing water, leading to death of the hatchlings or,

alternatively, modifying river flows to sustain an „unnatural‟ event which results in more water

loss (Water Technology, 2006)

Figure C- 1: Comparison of the forest-grass edge of an area of moira-grass plain in 1947

(left) and 1984 (right). Colonisation by red gums can be clearly seen. „Restoring‟ natural flows may instigate another change that could be perceived as damaging the current forest ecosystem. Photographs courtesy of the then Department of Property and Services of the Victorian Government (Bren, 2005).

A Method for Quantifying Change

The discussion above suggests that assessing option performance soley in terms of the change in

„the number of years each side of the forest experiences undesirable flooding‟ may be too

simplistic. Instead we also quantified the proportion of the forest that is flooded for each option.

Quantifying the proportion of the forest that is flooded

Forest flooding can be quantified by using the relationship developed by Bren et. al., (1987):



P% = -435.40 + 47.60 ln(Qp) Qp < 68,500 ML/d (1)

P% = 93.5 Qp > 68,500 ML/d

Where, where P% is the percentage of the forest inundated and Qp (ML/d) is the maximum daily

flow at Tocumwal during the period of inundation. Flows at Tocumwal are available from option

modelling.

Forest flooding is of particular concern above about 10,600 ML/d, below this flow, floods can be

retained in less ecologically significant areas of the forest. Substituting 10,600 ML/d into equation

1 suggests that 5.8% of the forest will be flooded at this flow.

Therefore, considering only that part of the forest flooded above 10,600 ML/d, the P value was

calculated as follows.

P=-435.40+47.60ln(Qp)-5.78 (2)

If P <0, P=0.

Calculation method

For each year in the modelling period (1895-2009) the following steps were undertaken:

1) Calculate the peak flow that occurs in the period Jan + Feb + Mar for each year for each option

2) Calculate the undesirable % of the forest based on equation 2

3) Based on all 115 P values for each option, draw a box plot that compares each option i.e. one

box for each option. The results are shown in Appendix D.

Future work: impacts on plant communities

As an additional project, the method described above could be expanded to assess the impacts on

plant communities. Flow limits are available for various plant communities (Bren pers. comm.) so

the change in flooding of these communities could be calculated in a similar way to estimate

changes in the percentage of forest flooded described above. Thus impacts on particular

communities could be described in quantitative terms.

Plant communities are grouped into vegetation alliances that relate to flooding frequency as shown

in Table C- 5. For each option it would be possible to comment on the likely expansion or

contraction of these plant communities. This would use the limits of flooding for the various

communities as determined by a body of work on the hydro-ecology of the forest (e.g. Roberts and

Marson 2000).



Table C- 5: Vegetation alliance as related to flood frequency class (Bren, 2005).

Flood frequency class

Vegetation Alliance

Approximate flooding frequency n in 22 years

Percentage of forest area (current conditions)

Very high Giant rush 16-19 1.8

High Moira grass

Red gum and moira grass

Red gum regeneration on plains

15-18 23.4

Moderate Red gum in conjunction with sedge, warrego grass, wallaby grass, and swamp wallaby grass in various combinations

12-16 57.7

Low Red gum & introductions

Red gum, wallaby grass and spike rush

Yellow box and black box woodlands

6-10 17.1

C.4 Other project specific indicators

This section briefly outlines the development and calculation of each of the indicators developed as

a part of the Investigation Phase. Further information on the development and calculation of each

of these indicators is provided in SKM (2009).

Forest losses

Barmah-Millewa forest losses are modelled in MSM-Bigmod as part of total losses in the reach

from Yarrawonga to Barmah. The variable “BARMILL” sums the majority of losses in the reach

from Yarrawonga to Barmah; however flow out to Barmah Lake is not included and must be added

separately.

Not all of the losses within the “BARMILL” variable are associated with overbank flooding

through the Barmah-Millewa forest. Part of objective one is to reduce losses in the Barmah-

Millewa Forest. The loss variables from “BARMILL” associated with overbank flooding were

assumed to be:

BARMAH FOREST (FI 129)

LOSSES IN FORESTS (BR 3)

OVERBANK FLOW THROUGH BARMAH (FI 19)

Losses through the Millewa, Tuppal and Bullatale systems (LS 44, 45, 46)

Whilst these variables are close to the magnitude of Barmah-Millewa Forest losses, the amount of

data available to calibrate these individual loss terms is small and at times anecdotal or based on

feedback from local staff. As such, uncertainty around individual components is expected to be

large. The confidence associated with total losses in the river reach from Yarrawonga to Barmah is

much higher as calibration is supported by the long term streamflow data from gauging stations.



Therefore both total losses from Yarrawonga to Barmah (BARMILL + FO 20) and the sum of the

above overbank flooding loss variables (Barmah forest losses) are considered. The indicator for this

objective is the average volume of water lost through the forest (BARMILL + FO20 and the

overbank flooding loss) over the unseasonal flooding period (December 15th to April 30

th).

Conservation of water resources

In Victoria, reliability assessment typically used announced February allocations for high and low

reliability water shares.

In NSW, it is common to report the announced allocation at October 1, the start of the irrigation

season, to assist irrigators with planting decisions. It is also common to look at the announced

allocation at April 30. The CSIRO Murray-Darling Basin Sustainable Yields Study reported the

maximum announced allocation for general security entitlements in the water years. This is almost

always the same as the April 30 allocations. For the purposes of the Barmah Choke Study, the

maximum allocation for general security entitlements has been adopted for the indicator.

The indicator results will present a table summarising key allocation thresholds for each State.

Table C- 6 shows the key allocation thresholds summary table.

Table C- 6: Key allocation thresholds summary table.

Allocation Threshold Scenario

Years with 100% allocation for general security entitlements (NSW)

Average allocation for general security entitlements (NSW)

Years with 100% allocation for high reliability water shares (Victoria)

Years with 100% allocation for low reliability water shares (Victoria)

Average allocation for high + low reliability water shares (Victoria)


In working towards the achievement of the primary objectives, the Barmah Choke Study also aims

to:

maintain the beneficial influence of the Barmah Choke on the flooding regime of the Barmah-

Millewa Forest

identify any significant impacts on the frequency and magnitude of environmental and

unregulated flows in the River Murray System, with the aim to minimise these where possible

identify any significant impacts to other areas or to third parties, with the aim to minimise

these wherever possible

Indicators have been developed to assess the achievement of each of these aims.



Maintain the beneficial influence of the Barmah Choke on the flooding regimes of the Barmah-Millewa Forest

Seasonal flooding during winter and/or spring is fundamental to the health of the Barmah-Millewa

Forest. The indicator for this objective looks at the proportion of years with small and large floods

in the Barmah-Millewa Forest and the maximum duration (in years) with no flood. Table C- 7

shows the results summary table adopted for this indicator.

Table C- 7: Beneficial flooding of the Barmah-Millewa Forest summary table.

Barmah-Millewa Forest flooding indicator Scenario

% of years with a medium/large flood of 25,000 ML/day at Yarrawonga

for >= 3 months

Maximum duration with no medium/large flood (years)

% of years with a small flood of 18,000 ML/day at Yarrawonga for >= 3

months.

Maximum duration with no small flood (years)

Identify and significant impacts on the frequency and magnitude of environmental and unregulated flows in the River Murray System

Seasonal flooding and unregulated flows are also fundamental to the health of other locations along

the River Murray System. To measure the impact of options on environmental and unregulated

flows a set of indicators have been developed based on the proportions of years different magnitude

flow events occur at a range of locations along the River Murray System and the maximum

duration between flow events. Table C- 8 shows the results summary table adopted for this

indicator.

Table C- 8: Beneficial environmental and unregulated flows assessment summary table.

Location / Indicator Scenario

Koondrook/Gunbower Wetlands

% of years with a medium/large flood of 35,000 ML/day at Torrumbarry

for >= 3 months


% of years with a small flood of 25,000 ML/day at Torrumbarry for >= 3

months


Hattah Lakes

% of years with a medium/large flood of 75,000 ML/day at Euston for

>= 1 month


% of years with a small flood of 45,000 ML/day at Euston for >= 3

months


Chowilla/Lindsay-Wallpolla



Location / Indicator Scenario

Koondrook/Gunbower Wetlands

% of years with a medium/large flood of 80,000 ML/day at the SA

border for >= 3 months


% of years with a small flood of 50,000 ML/day at the SA border for >=

3 months


Unregulated Flows

Average flow to SA in excess of entitlement (GL/year)

% of years where flows to SA <1,850 GL/year

Third party or other area impacts: maintain water levels in Lake Victoria and the Menindee Lakes for cultural heritage reasons

Lake Victoria

Lake Victoria is a significant cultural and heritage area for Indigenous Australians. Artefacts of

indigenous heritage around the Lake include burial grounds, shell middens, fireplaces and stone

artefacts. Foreshore vegetation is essential for the stabilisation of the Lake foreshore and protection

of indigenous heritage artefacts.

The Lake Victoria operating strategy (MDBC, 2002) was developed with consideration for the

foreshore vegetation and the protection of indigenous heritage artefacts. The operating strategy

includes a range of target storage levels along with a number of conditional rules which dictate

alternative targets during periods of particularly high or low system storage.

To assess the (cultural heritage) impact of options on Lake Victoria, indicators were developed to

check compliance with the operating strategy (including the conditional rules). Table C- 9 shows

the results table adopted for this indicator.

Table C- 9: Compliance with the Lake Victoria operating strategy summary table.

Indicator Scenario

Compliance

with the target

Proportion of time target not

applied due to Conditional Rules

% of years Lake Victoria level on the last day

of February meets the target (≤25.5 m AHD)


of March meets the target (≤25.6 m AHD)


of April meets the target (≤24.5 m AHD)

% of time (days) where lake level is > 24.5 m

AHD in May (target = minimal)



Indicator Scenario

Compliance

with the target

Proportion of time target not

applied due to Conditional Rules

% of time (days) during winter and spring

where lake level is ≥27.0 m AHD (target =

minimal)

Menindee Lakes

The Menindee Lakes are also a significant cultural heritage area for Indigenous Australia with

similar artefacts and threats as Lake Victoria. The operation of Lake Victoria does not explicitly

consider cultural and heritage issues, however a „Consent to Destroy‟ authorisation is required to

exceed the maximum surcharge level in either Lake Menindee or Lake Cawndilla (60.45 m AHD).

An appropriate indicator would be the number of events where lake volume exceeds the maximum

surcharge volume in Lake Menindee or Lake Cawndilla. Rules within the current model prevent

modelled volumes in Lake Menindee or Lake Cawndilla exceeding the maximum surcharge

volume. As such, the model results will never be in violation of this requirement. Additionally,

none of the proposed options would be expected to impact on the Menindee Lakes. As such, this

indicator does not need to be assessed.

Third party or other area impacts: avoid undesirable flooding of the Werai Forest

The Edward River has an in-stream capacity of 2,700 ML/day downstream of Steven‟s Weir. Flows

greater than this will flood the Werai Forest, which is undesirable over the unseasonal flooding

period (15th December to 30

th April). To assess the impact of options, an undesirable flooding

indicator, similar to that for the Barmah-Millewa Forest, has been developed.

Table C- 10 shows the undesirable flooding assessment summary table, with floods classified by

magnitude and duration.

Table C- 10: Undesirable flooding summary matrix.


Duration 2,701 –

3,100

3,101 –

3,500

3,501 –

4,000

4,001 –

4,500

>4,500

0-2 days

3-7 days

>7 days

Total by Flow

Total years of unseasonal flooding

Total number of years

Total number of events



Third party or other area impacts: avoid undesirable exceedance of 25,000 ML/day downstream of Hume Reservoir

The bankfull capacity of the River Murray between Hume and Yarrawonga Weir is

25,000 ML/day. Exceedence of this capacity from 1 January to 30 April is undesirable. To assess

this, the number of years the maximum flow during this period exceeded 25,000 ML/day were

counted, based on flow at Doctor‟s Point. Note, declining flow periods exceeding 25,000 ML/day

from January 1st were eliminated to allow for model adjustment

Table C- 11 shows the results summary table for this indicator.

Table C- 11: Undesirable Exceedances of 25,000 ML/day downstream of Hume Reservoir.

Scenario Years Capacity Exceeded (Jan – Apr)

Number of Years % of Years

Third party or other area impacts: avoid undesirable exceedance of the capacity of the Edward River offtake

The operating capacity of the Edward River offtake was 2,000 ML/day, however this has been

reduced in recent years to 1,600 ML/day to address concern about damage to the forest due to high

water levels. Exceedence of this capacity from 1 January to 30 April is undesirable. To assess this,

the number of years the maximum flow during this period exceeded 1,600 ML/day were counted.

Note, declining flow periods exceeding 1,600 ML/day from January 1st were eliminated to allow

for model adjustment


Table C- 12: Undesirable Exceedances of Edward River offtake capacity (1,600 ML/day).

Scenario Years Capacity Exceeded (Jan – Apr)


Third party or other area impacts: avoid undesirable exceedance of the capacity of the Gulpa River offtake

The operating capacity of the Gulpa River offtake is 350 ML/day. Exceedence of this capacity from

1 January to 30 April is undesirable. To assess this, the number of years the maximum flow during

this period exceeded 350 ML/day were counted. Note, declining flow periods exceeding 350

ML/day from January 1st were eliminated to allow for model adjustment




Table C- 13: Undesirable Exceedances of Gulpa River offtake capacity (350 ML/day).

Scenario Years Capacity Exceeded (Feb* – Apr)


* Whilst the official summer target capacity of the Gulpa offtake is 350 ML/day, the model retains the spring

capacity of 750 ML/day through to the end of January. As such, the indicator is based on the period from

February to April.

Third party or other area impacts: maintain Hydropower operation at Hume, Yarrawonga and Dartmouth

To assess the effect of options on hydropower general, the annual average volume (GWh) of power

generated at Dartmouth is considered. Power generation at Hume and Yarrawonga is not calculated

within the MSM-Bigmod model and as such cannot be reported for the Barmah Choke Study.


Table C- 14: Power generation at Dartmouth summary table.

Scenario Average annual power

generation (GWh)

Third party or other area impacts: maintain recreational water levels

Lake Mulwala and Euston Weir are both used for recreational boating. Reductions in water levels

can affect this. As an indicator of recreational potential, key water level statistics between January

and April are considered for both sites.

Table C- 15 and Table C- 16 show the results summary table for this indicator for Lake Mulwala

and Euston Weir respectively.

Table C- 15: Mulwala water level statistics summary table.

Scenario Average water

level (m AHD)

Median water

level (m AHD)

Minimum water

level (m AHD)

95th

percentile water

level (m AHD)

Table C- 16: Euston Weir water level statistics summary table.

Scenario Average water

level (m AHD)

Median water

level (m AHD)

Minimum water

level (m AHD)

95th

percentile water

level (m AHD)



C.5 MDBA standard indicators

Table C- 17 summarises the MDBA standard hydrological indicators that will be used for the

Individual Options Phase of the Barmah Choke Study. These indicators cover a range of the key

hydrological characteristics of the River Murray System including allocations, diversions, flows,

storage and salinity.

Further detail about each of the indicators is provided in MDBA (2010a).

Table C- 17: MDBA standard hydrological indicators for the Barmah Choke Study.

Indicator Unit

NSW Allocations

Percentage of years NSW Murray high security allocations <100% (Jun) %

Mean NSW Murray high security allocation (Jun) GL/year

Mean NSW Murray general security allocation (Nov) GL/year

Mean NSW Lower Darling general security allocation (Nov) GL/year

Victoria Allocations

Percentage of years Victorian high reliability water share <100% (Feb) %

Mean Victoria high reliability water share (Feb) GL/year

Minimum Victorian high reliability water share (Feb) GL/year

Percentage of years Victorian low reliability water share <100% (Feb) %

Mean Victorian low reliability water share (Feb) GL/year

South Australia‟s Entitlement Flows

Percentage of years SA entitlement restricted (all months)

Maximum annual SA restriction (all months) GL/year

Mean annual SA restriction (all months) GL/year

Minimum annual SA flow (all months) GL/year

NSW Diversions

Mean annual NSW Murray diversion (all months) GL/year

Minimum annual NSW Murray diversion (all months) GL/year

Mean annual NSW Lower Darling diversion (all months) GL/year

Minimum annual NSW Lower Darling diversion (all months) GL/year

Victorian Diversions

Mean annual Vic Murray diversion (all months) GL/year

Minimum annual Vic Murray diversion (all months) GL/year

South Australian Diversions

Mean annual SA Murray diversion (all months) GL/year

Minimum annual SA Murray diversion (all months) GL/year

Total Diversions

Mean annual total Murray diversion (all months) GL/year

Minimum annual total Murray diversion (all months) GL/year

General Flow Indicators

Mean annual flow downstream of Doctors Point (all months) GL/year

Mean annual flow downstream of Yarrawonga (all months) GL/year

Mean annual flow downstream of Euston (all months) GL/year

Mean annual Burtundy flow (all months) GL/year

Mean annual Darling Anabranch outflow (all months) GL/year

Mean annual flow to South Australia (all months) GL/year

Mean annual flow at Lock 1 (all months) GL/year



Indicator Unit

Mean annual flow over the Barrages (all months) GL/year

Storage Indicators

Mean annual Dartmouth Reservoir loss (all months) GL/year

Mena annual Hume Reservoir loss (all months) GL/year

Mean annual Lake Victoria loss (all months) GL/year

Mean annual Total Murray system loss (all months) GL/year

Mean annual Total Darling loss (all months) GL/year

Mean annual Dartmouth Reservoir spill (all months) GL/year

Mean annual Hume Reservoir spill (all months) GL/year

Mean annual Lake Victoria spill (all months) GL/year

Level Indicators

Mean Lower Lakes level (all months) mAHD

Minimum Lower Lakes level (all months) mAHD

General Salinity Indicators

Mean daily Morgan salinity (all months) EC

95 percentile daily Morgan salinity (all months) EC

Mean daily Burtundy salinity (all months) EC

Mean daily Mannum salinity (all months) EC

Mean daily Murray Bridge salinity (all months) EC



Appendix D Option modelling results summary

Table D- 1: Option modelling results summary- shortfalls downstream of Yarrawonga Weir.

Shortfall Types

Op

tio

n 1

Op

tio

n 2

Op

tio

n 3

a

Op

tio

n 3

b

Op

tio

n 4

a

Op

tio

n 4

b

Op

tio

n 5

a

Op

tio

n 5

b

Op

tio

n 6

a

Op

tio

n 6

b

Op

tio

n 6

c

Op

tio

n 7

a*

Op

tio

n 7

b*

Op

tio

n 7

c*

Op

tio

n 7

d*

Op

tio

n 1

0

Op

tio

n 1

1

Op

tio

n 1

2a

Op

tio

n 1

2b

Op

tio

n 1

2c

Op

tio

n 1

3

Op

tio

n 1

5

Op

tio

n 1

6a

Op

tio

n 1

6b

Op

tio

n 1

6c

Op

tio

n 1

7


Number (total) 13 14 12 13 7 5 14 15 10 5 5 13 13 13 13 13 12 9 9 8 15 8 14 12 9 4

Number (type I- peak demand) 12 12 12 13 5 4 12 13 8 3 4 12 12 12 12 12 11 9 9 8 14 7 14 12 9 3

Number (type II- lower system storage) 1 2 0 0 2 1 2 2 2 2 1 1 1 1 1 1 1 0 0 0 1 1 0 0 0 1

Average volume (GL) 2.4 2.7 2.2 2.1 1.2 1.1 2.7 2.8 2.0 0.6 0.9 2.4 2.4 2.4 2.4 2.3 2.6 3.6 3.2 3.0 2.8 1.2 2.4 2.6 3.6 0.3

Average duration (days) 3.4 3.6 3.1 2.9 2.0 1.8 3.6 3.5 2.8 1.4 1.8 3.4 3.4 3.4 3.4 3.3 3.5 4.3 3.9 3.8 3.5 1.6 3.2 3.5 4.4 1.0


Number 8 7 5 5 3 3 7 6 2 4 3 8 8 8 8 8 7 7 9 10 4 2 7 7 8 4






Number 7 7 5 7 6 5 7 7 7 5 5 7 7 7 7 7 7 7 5 5 7 6 7 7 6 5





Total shortfalls

Number (total) 28 28 22 25 16 13 28 28 19 14 13 28 28 28 28 28 26 23 23 23 26 16 28 26 23 13



*Effect on shortfalls for these options was not modelled and has been set to the values modelled for Option 1.

Table D- 2: Option modelling results summary- unseasonal flooding of the Barmah-Millewa Forest.

Unseasonal Flooding

Op

tio

n 1

Op

tio

n 2

Op

tio

n 3

a

Op

tio

n 3

b

Op

tio

n 4

a*

Op

tio

n 4

b*

Op

tio

n 5

a

Op

tio

n 5

b

Op

tio

n 6

a*

Op

tio

n 6

b*

Op

tio

n 6

c*

Op

tio

n 7

a

Op

tio

n 7

b

Op

tio

n 7

c

Op

tio

n 7

d

Op

tio

n 1

0

Op

tio

n 1

1

Op

tio

n 1

2a

Op

tio

n 1

2b

Op

tio

n 1

2c

Op

tio

n 1

3

Op

tio

n 1

5

Op

tio

n 1

6a

Op

tio

n 1

6b

Op

tio

n 1

6c

Op

tio

n 1

7*

Total years of unseasonal flooding 63 64 61 68 63 63 55 29 63 63 63 58 56 32 31 44 66 62 59 58 62 57 67 66 66 63

Total years of moderate unseasonal flooding 33 31 33 36 33 33 28 10 33 33 33 27 33 12 13 27 34 32 27 23 33 29 33 35 31 33

Total years of more severe unseasonal flooding 29 30 26 26 29 29 23 16 29 29 29 26 20 16 14 16 27 21 19 19 26 21 29 27 26 29

Proportion of wet years for each side of the forest 40% 40% 37% 39% 40% 40% 32% 18% 40% 40% 40% 35% 32% 19% 18% 26% 39% 32% 29% 27% 37% 31% 40% 39% 36% 40%

* Effect on unseasonal flooding for these options was not modelled and has been set to the values modelled for Option 1.



Figure D- 1: Option modelling results summary- proportion of the Barmah-Millewa Forest flooded unseasonally each year.

Note the results shown in Figure D- 1 are consistent with the unseasonal flooding results discussed in the main body of this report. In particular, the Lake Mulwala option (Option 5, particularly sub-option 5b) is

particularly effective in reducing the proportion of the Barmah-Millewa Forest flooded unseasonally each year, as are the larger of the storage at „The Drop‟ on Mulwala Canal options (Options 7c and 7d). Bypass

options, such as Option 12 are also effective.

Table D- 3: Option modelling results summary- Barmah Choke Study specific indicators. Note results the results for Option 1 represent the absolute results, results for all other options indicate change from Option 1.

Indicator

Op

tio

n 1

Op

tio

n 2

Op

tio

n 3

a

Op

tio

n 3

b

Op

tio

n 4

a

Op

tio

n 4

b

Op

tio

n 5

a

Op

tio

n 5

b

Op

tio

n 6

a

Op

tio

n 6

b

Op

tio

n 6

c

Op

tio

n 7

a

Op

tio

n 7

b

Op

tio

n 7

c

Op

tio

n 7

d

Op

tio

n 1

0

Op

tio

n 1

1

Op

tio

n 1

2a

Op

tio

n 1

2b

Op

tio

n 1

2c

Op

tio

n 1

3

Op

tio

n 1

5

Op

tio

n 1

6a

Op

tio

n 1

6b

Op

tio

n 1

6c

Op

tio

n 1

7

Forest losses (15th December to 30

th April)

Total loss from Yarrawonga to Barmah (GL/year) 147.9 0.5 1.1 0.7 N/A N/A -0.7 -1.8 N/A N/A N/A N/A N/A N/A N/A 5.4 -0.3 -2.0 -2.9 -3.3 -0.6 -4.7 -0.1 0.0 -1.0 N/A

Barmah Forest loss (GL/year) 132.1 0.8 2.5 1.2 N/A N/A -0.8 -2.1 N/A N/A N/A N/A N/A N/A N/A 5.0 -0.3 -2.6 -4.0 -4.6 -0.7 -6.0 0.0 0.1 -1.3 N/A

Allocations

Years with 100% allocation for general security entitlement (NSW) 71.3% 0.0 0.0 0.0 N/A N/A 0.0 0.0 N/A N/A N/A N/A N/A N/A N/A 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 N/A

Average allocation for general security entitlement (NSW) 85.6 -0.1 0.0 0.1 N/A N/A 0.0 0.0 N/A N/A N/A N/A N/A N/A N/A 0.0 0.2 0.2 0.2 0.2 0.0 0.0 0.2 0.1 0.2 N/A

Years with 100% allocation for high reliability water shares (Victoria) 98.2% 0.0 0.0 0.0 N/A N/A 0.0 0.0 N/A N/A N/A N/A N/A N/A N/A 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 N/A

Years with 100% allocation for low reliability water shares (Victoria) 77.0% 0.0 0.0 0.0 N/A N/A 0.0 0.0 N/A N/A N/A N/A N/A N/A N/A 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 N/A

Average allocation for high + low reliability water shares (Victoria) 182.0 0.1 -0.3 0.0 N/A N/A 0.0 0.0 N/A N/A N/A N/A N/A N/A N/A 0.0 -0.1 -0.1 -0.4 -0.3 0.0 0.2 -0.1 -0.1 -0.1 N/A

Beneficial flooding of the Barmah-Millewa Forest

% of years with a medium/large flood of 25,000 ML/day at Yarrawonga for >= 2 months 16.8% 0.0 0.0 0.0 N/A N/A 0.0 0.0 N/A N/A N/A N/A N/A N/A N/A 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 N/A

Maximum duration with no medium/large flood (years) 21 0.0 0.0 0.0 N/A N/A 0.0 0.0 N/A N/A N/A N/A N/A N/A N/A 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 N/A

% of years with a small flood of 18,000 ML/day at Yarrawonga for >= 3 months 13.3% 0.0 0.0 0.0 N/A N/A 0.0 0.0 N/A N/A N/A N/A N/A N/A N/A 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 N/A

Maximum duration with no small flood (years) 21 0.0 0.0 0.0 N/A N/A 0.0 0.0 N/A N/A N/A N/A N/A N/A N/A 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 N/A

Beneficial flooding of Koondrook/Gunbower Wetlands

% of years with a medium/large flood of 35,000 ML/day at Torrumbarry for >= 3 months 4.4% 0.0 0.0 0.0 N/A N/A 0.0 0.0 N/A N/A N/A N/A N/A N/A N/A 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 N/A


% of years with a small flood of 25,000 ML/day at Torrumbarry for >= 3 months 15.0% 0.0 0.0 0.0 N/A N/A 0.0 0.0 N/A N/A N/A N/A N/A N/A N/A 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 N/A


Beneficial flooding of Hattah Lakes

0

5

10

15

20

25

30

35

Option 1 Option 2 Option 3a

Option 3b

Option 5a

Option 5b

Option 7a

Option 7b

Option 7c

Option 7d

Option 10

Option 11

Option 12a

Option 12b

Option 12c

Option 13

Option 15

Option 16a

Option 16b

Option 16c

Pro

po

rtio

n o

f th

e fo

rest fl

oo

ded



Indicator

Op

tio

n 1

Op

tio

n 2

Op

tio

n 3

a

Op

tio

n 3

b

Op

tio

n 4

a

Op

tio

n 4

b

Op

tio

n 5

a

Op

tio

n 5

b

Op

tio

n 6

a

Op

tio

n 6

b

Op

tio

n 6

c

Op

tio

n 7

a

Op

tio

n 7

b

Op

tio

n 7

c

Op

tio

n 7

d

Op

tio

n 1

0

Op

tio

n 1

1

Op

tio

n 1

2a

Op

tio

n 1

2b

Op

tio

n 1

2c

Op

tio

n 1

3

Op

tio

n 1

5

Op

tio

n 1

6a

Op

tio

n 1

6b

Op

tio

n 1

6c

Op

tio

n 1

7

% of years with a medium/large flood of 75,000 ML/day at Euston for >= 1 month 9.7% 0.0 0.0 0.0 N/A N/A 0.0 0.0 N/A N/A N/A N/A N/A N/A N/A 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 N/A


% of years with a small flood of 45,000 ML/day at Euston for >= 3 months 12.4% 0.0 0.0 0.0 N/A N/A 0.0 0.0 N/A N/A N/A N/A N/A N/A N/A 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 N/A


Beneficial flooding of Chowilla/Lindsay-Wallpolla

% of years with a medium/large flood of 80,000 ML/day at SA border for >= 3 months 4.4% 0.0 0.0 0.0 N/A N/A 0.0 0.0 N/A N/A N/A N/A N/A N/A N/A 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 N/A


% of years with a small flood of 50,000 ML/day at SA border for >= 3 months 13.3% 0.0 0.0 0.0 N/A N/A 0.0 0.0 N/A N/A N/A N/A N/A N/A N/A 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 N/A


Unregulated flows

Average flow to SA in excess of entitlement (GL/year) 4435.9 -2.5 -0.2 -0.3 N/A N/A 0.1 0.9 N/A N/A N/A N/A N/A N/A N/A 0.0 -3.5 -5.4 -8.5 -9.1 0.6 4.8 -1.7 -2.0 -3.3 N/A

% of years where flows to SA < 1,850 GL/year 94.7% 0.0 0.0 0.0 N/A N/A 0.0 0.0 N/A N/A N/A N/A N/A N/A N/A 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 N/A

Lake Victoria target levels

% of years Lake Victoria level of the last day of February meets target (≤26.5 m AHD) 97.9% 0.0 0.0 0.0 N/A N/A 0.0 0.0 N/A N/A N/A N/A N/A N/A N/A 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 N/A

Proportion of time (years) target not applied due to conditional rules 57.5% 0.0 0.0 0.0 N/A N/A 0.0 0.0 N/A N/A N/A N/A N/A N/A N/A 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 N/A

% of years Lake Victoria level of the last day of March meets target (≤25.6 m AHD) 94.0% 0.0 0.0 0.0 N/A N/A 0.0 0.0 N/A N/A N/A N/A N/A N/A N/A 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 N/A


% of years Lake Victoria level of the last day of April meets target (≤24.6 m AHD) 90.2% 0.0 0.0 0.0 N/A N/A 0.0 0.0 N/A N/A N/A N/A N/A N/A N/A 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 N/A


% of time (days) Lake Victoria level is > 25.5 m AHD in May (target = minimal) 7.7% 0.0 0.0 0.0 N/A N/A 0.0 0.0 N/A N/A N/A N/A N/A N/A N/A 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 N/A

Proportion of time (days) target not applied due to conditional rules 50.9% 0.0 0.0 0.0 N/A N/A 0.0 0.0 N/A N/A N/A N/A N/A N/A N/A 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 N/A

% of time (days) during winter & spring where lake level is ≥ 27.0 m AHD in (target = minimal) 28.0% 0.0 0.0 0.0 N/A N/A 0.0 0.0 N/A N/A N/A N/A N/A N/A N/A 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 N/A

Werai Forest flooding

% of years of undesirable flooding 43.0% 0.0 0.0 0.0 N/A N/A 0.0 -0.1 N/A N/A N/A N/A N/A N/A N/A 0.0 0.0 0.3 0.3 0.3 -0.1 -0.1 0.0 0.0 0.1 N/A

Undesirable exceedences- other locations

% of years capacity downstream of Hume Reservoir exceeded (25,000 ML/day, Jan – Apr) 2.6% 0.0 0.0 0.0 N/A N/A 0.0 0.0 N/A N/A N/A N/A N/A N/A N/A 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 N/A

% of years capacity of Edward offtake exceeded (1,600 ML/day Jan – Apr) 45.6% -0.1 -0.1 0.0 N/A N/A 0.0 0.0 N/A N/A N/A N/A N/A N/A N/A 0.0 0.0 -0.1 -0.1 0.0 -0.1 -0.1 0.0 0.0 -0.1 N/A

% of days capacity of Gulpa offtake exceeded (350 ML/day, Feb – Apr) 27.4% 0.0 0.0 0.0 N/A N/A 0.0 0.0 N/A N/A N/A N/A N/A N/A N/A 0.0 0.0 0.0 -0.1 -0.1 0.0 -0.1 0.0 0.0 0.0 N/A

Hydropower generation

Average annual power generation at Dartmouth Reservoir (GWh) 287.3 -0.2 1.1 0.2 N/A N/A 0.0 0.0 N/A N/A N/A N/A N/A N/A N/A 0.0 0.0 -0.5 -1.0 -1.2 0.1 -0.7 0.0 -0.5 -0.5 N/A

Recreational water levels (Jan – Apr)

Lake Mulwala Average water level (m AHD) 124.8 0.0 0.0 0.0 N/A N/A -0.1 -0.5 N/A N/A N/A N/A N/A N/A N/A 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 N/A

Median water level (m AHD) 124.8 0.0 0.0 0.0 N/A N/A -0.1 -0.5 N/A N/A N/A N/A N/A N/A N/A 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 N/A

Minimum water level (m AHD) 123.9 0.0 -0.7 0.1 N/A N/A -0.2 -1.0 N/A N/A N/A N/A N/A N/A N/A 0.0 0.0 0.0 0.1 0.1 0.2 0.3 0.0 0.0 0.0 N/A

95th percentile water level (m AHD 124.6 0.0 0.0 0.0 N/A N/A -0.1 -0.5 N/A N/A N/A N/A N/A N/A N/A 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 N/A

Euston Weir Average water level (m AHD) 47.7 0.0 0.0 0.0 N/A N/A 0.0 0.0 N/A N/A N/A N/A N/A N/A N/A 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 N/A

Median water level (m AHD) 47.7 0.0 0.0 0.0 N/A N/A 0.0 0.0 N/A N/A N/A N/A N/A N/A N/A 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 N/A

Minimum water level (m AHD) 46.9 0.0 0.0 0.0 N/A N/A 0.0 0.0 N/A N/A N/A N/A N/A N/A N/A 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 N/A

95th percentile water level (m AHD 47.7 0.0 0.0 0.0 N/A N/A 0.0 0.0 N/A N/A N/A N/A N/A N/A N/A 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 N/A

Table D- 4: Option modelling results summary- MDBA standard indicators. Note results the results for Option 1 represent the absolute results, results for all other options indicate change from Option 1.

Indicator

Op

tio

n 1

Op

tio

n 2

Op

tio

n 3

a

Op

tio

n 3

b

Op

tio

n 4

a

Op

tio

n 4

b

Op

tio

n 5

a

Op

tio

n 5

b

Op

tio

n 6

a

Op

tio

n 6

b

Op

tio

n 6

c

Op

tio

n 7

a

Op

tio

n 7

b

Op

tio

n 7

c

Op

tio

n 7

d

Op

tio

n 1

0

Op

tio

n 1

1

Op

tio

n 1

2a

Op

tio

n 1

2b

Op

tio

n 1

2c

Op

tio

n 1

3

Op

tio

n 1

5

Op

tio

n 1

6a

Op

tio

n 1

6b

Op

tio

n 1

6c

Op

tio

n 1

7

SRA Hydrology Index

Original Murray-Lower Darling Index 0.588 0.001 0.002 0.000 N/A N/A 0.000 -0.001 N/A N/A N/A N/A N/A N/A N/A 0.000 0.000 0.000 0.000 0.000 0.000 0.001 0.000 0.000 0.000 N/A

Zone 1 U/s Hume 0.763 0.000 0.002 0.000 N/A N/A 0.000 0.000 N/A N/A N/A N/A N/A N/A N/A 0.000 0.001 0.000 0.001 0.001 0.000 0.001 0.000 0.001 0.000 N/A

Zone 2 Hume to Yarrawonga 0.738 0.002 0.005 0.000 N/A N/A -0.002 -0.007 N/A N/A N/A N/A N/A N/A N/A 0.000 0.001 0.003 0.003 0.003 0.003 0.006 0.001 0.002 0.003 N/A

Zone 3 Yarrawonga to Wakool Junction 0.605 0.001 0.002 -0.001 N/A N/A 0.000 -0.001 N/A N/A N/A N/A N/A N/A N/A -0.001 0.000 0.001 0.002 0.002 0.000 0.001 0.000 0.000 0.000 N/A

Zone 4 Wakool to Wentworth 0.615 0.001 0.002 0.002 N/A N/A 0.000 -0.003 N/A N/A N/A N/A N/A N/A N/A 0.000 -0.002 -0.002 -0.003 -0.003 -0.003 0.000 0.000 -0.002 -0.002 N/A

Zone 5 Wentworth to Lock 3 0.524 -0.001 0.000 -0.001 N/A N/A -0.001 0.000 N/A N/A N/A N/A N/A N/A N/A 0.000 0.001 0.001 0.000 0.000 0.000 0.001 0.000 0.001 0.001 N/A

Zone 6 Lower Darling 0.444 0.000 0.001 0.002 N/A N/A 0.000 0.000 N/A N/A N/A N/A N/A N/A N/A 0.000 0.000 0.000 0.000 0.000 0.000 -0.001 0.000 0.000 -0.001 N/A

Zone 7 Lock 3 to Lakes 0.510 0.001 0.004 0.000 N/A N/A 0.000 -0.001 N/A N/A N/A N/A N/A N/A N/A 0.000 0.001 0.001 0.001 0.001 0.000 0.001 0.000 0.001 0.001 N/A



Indicator

Op

tio

n 1

Op

tio

n 2

Op

tio

n 3

a

Op

tio

n 3

b

Op

tio

n 4

a

Op

tio

n 4

b

Op

tio

n 5

a

Op

tio

n 5

b

Op

tio

n 6

a

Op

tio

n 6

b

Op

tio

n 6

c

Op

tio

n 7

a

Op

tio

n 7

b

Op

tio

n 7

c

Op

tio

n 7

d

Op

tio

n 1

0

Op

tio

n 1

1

Op

tio

n 1

2a

Op

tio

n 1

2b

Op

tio

n 1

2c

Op

tio

n 1

3

Op

tio

n 1

5

Op

tio

n 1

6a

Op

tio

n 1

6b

Op

tio

n 1

6c

Op

tio

n 1

7

Zone 8 Lower Lakes 0.358 0.000 0.000 -0.002 N/A N/A -0.001 -0.001 N/A N/A N/A N/A N/A N/A N/A 0.000 -0.001 -0.001 -0.003 -0.002 0.000 -0.002 -0.001 0.000 0.000 N/A

Morgan salinity (EC)

Average Morgan salinity 520.7 0.4 0.5 -0.4 N/A N/A 0.2 0.3 N/A N/A N/A N/A N/A N/A N/A 0.0 -0.3 -0.9 -0.6 -0.7 -1.3 -1.4 -0.2 -0.5 -1.3 N/A

95th percentile Morgan salinity 804 3 0 -3 N/A N/A 2 5 N/A N/A N/A N/A N/A N/A N/A 0 1 -1 -1 -2 -6 -7 1 0 -1 N/A

Average annual diversions (GL/year)

NSW Murray diversions 1787.7 0.8 -0.3 -0.2 N/A N/A 0.0 0.0 N/A N/A N/A N/A N/A N/A N/A 0.0 2.5 3.4 4.5 4.3 1.4 -2.3 1.7 2.0 3.4 N/A

Victorian Murray diversions 1736.1 0.4 -3.2 0.0 N/A N/A 0.0 0.0 N/A N/A N/A N/A N/A N/A N/A 0.0 -0.3 -0.8 -1.7 -1.8 -0.5 50.5* -0.1 -0.5 -0.8 N/A

SA diversions 707.2 0.2 0.1 -0.2 N/A N/A 0.0 0.0 N/A N/A N/A N/A N/A N/A N/A 0.0 0.2 0.2 0.1 0.1 0.4 0.1 0.2 0.3 0.2 N/A

Lower Darling diversions 132.9 -0.1 0.4 -0.6 N/A N/A 0.0 0.0 N/A N/A N/A N/A N/A N/A N/A 0.0 0.0 -0.1 -0.1 -0.1 0.0 -0.1 0.0 -0.1 -0.1 N/A

Total diversions 4363.9 1.3 -3.0 -1.0 N/A N/A 0.0 0.0 N/A N/A N/A N/A N/A N/A N/A 0.0 2.3 2.7 2.7 2.6 1.3 48.3 1.7 1.7 2.7 N/A

SA country towns diversions 48.0 0.0 0.0 0.0 N/A N/A 0.0 0.0 N/A N/A N/A N/A N/A N/A N/A 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 N/A

Metropolitan Adelaide diversions 99.1 0.0 0.0 0.0 N/A N/A 0.0 0.0 N/A N/A N/A N/A N/A N/A N/A 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 N/A

Other SA diversions 560.1 0.2 0.1 -0.2 N/A N/A 0.0 0.0 N/A N/A N/A N/A N/A N/A N/A 0.0 0.2 0.2 0.1 0.2 0.4 0.1 0.2 0.3 0.2 N/A

Average cap adjustments (GL/year)

NSW Murray -2.4 0.0 0.0 0.0 N/A N/A 0.0 0.0 N/A N/A N/A N/A N/A N/A N/A 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 N/A

Victorian Murray 74.4 0.0 0.0 0.0 N/A N/A 0.0 0.0 N/A N/A N/A N/A N/A N/A N/A 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 N/A

South Australia 32.4 0.0 0.0 0.0 N/A N/A 0.0 0.0 N/A N/A N/A N/A N/A N/A N/A 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 N/A

Lower Darling 14.1 0.0 0.0 0.0 N/A N/A 0.0 0.0 N/A N/A N/A N/A N/A N/A N/A 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 N/A

Total cap adjustment 118.6 0.0 0.0 0.0 N/A N/A 0.0 0.0 N/A N/A N/A N/A N/A N/A N/A 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 N/A

Tributary inflows (GL/year)

Murrumbidgee 1224.6 0.0 0.0 0.0 N/A N/A 0.0 0.0 N/A N/A N/A N/A N/A N/A N/A 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 N/A

Billabong Creek 307.1 0.0 0.0 0.0 N/A N/A 0.0 0.0 N/A N/A N/A N/A N/A N/A N/A 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 N/A

Menindee Lakes inflow 1721.1 0.0 0.0 0.0 N/A N/A 0.0 0.0 N/A N/A N/A N/A N/A N/A N/A 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 N/A

Goulburn River 1450.2 0.0 0.0 0.0 N/A N/A 0.0 0.0 N/A N/A N/A N/A N/A N/A N/A 0.0 0.0 0.0 0.0 0.0 0.0 48.9* 0.0 0.0 0.0 N/A

Broken Creek 178.2 0.0 0.0 0.0 N/A N/A 0.0 0.0 N/A N/A N/A N/A N/A N/A N/A 0.0 0.0 0.0 0.0 0.0 30.4** 48.5* 0.0 0.0 0.0 N/A

Campaspe River 151.2 0.0 0.0 0.0 N/A N/A 0.0 0.0 N/A N/A N/A N/A N/A N/A N/A 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 N/A

Loddon flow at Appin South 57.6 0.0 0.0 0.0 N/A N/A 0.0 0.0 N/A N/A N/A N/A N/A N/A N/A 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 N/A

Total tributary flow 5090.1 0.0 0.0 0.0 N/A N/A 0.0 0.0 N/A N/A N/A N/A N/A N/A N/A 0.0 0.0 0.0 0.0 0.0 30.4 97.5 0.0 0.0 0.0 N/A

Allocations

Mean NSW high security allocation 99.1 0.0 0.0 0.0 N/A N/A 0.0 0.0 N/A N/A N/A N/A N/A N/A N/A 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 N/A

Mean other NSW general security allocation 81.6 0.0 0.3 0.1 N/A N/A 0.0 0.0 N/A N/A N/A N/A N/A N/A N/A 0.0 0.1 0.1 0.2 0.2 0.1 -0.3 0.1 0.0 0.1 N/A

Minimum other NSW general security allocation 1.7 0.0 1.8 -0.1 N/A N/A 0.0 0.0 N/A N/A N/A N/A N/A N/A N/A 0.0 -0.1 -0.1 0.0 -0.1 0.0 -0.1 -0.1 0.9 -0.1 N/A

Minimum Victorian February allocation 13.0 -1.0 0.0 2.0 N/A N/A 0.0 0.0 N/A N/A N/A N/A N/A N/A N/A 0.0 2.0 1.0 1.0 1.0 0.0 2.0 2.0 1.0 1.0 N/A

% of years Victorian allocation < 100% 2.6 0.0 0.0 0.0 N/A N/A 0.0 0.0 N/A N/A N/A N/A N/A N/A N/A 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 N/A

Mean Victorian February allocation 180.5 0.1 -0.3 0.0 N/A N/A 0.0 0.0 N/A N/A N/A N/A N/A N/A N/A 0.0 -0.1 -0.1 -0.4 -0.3 0.0 0.2 0.0 -0.1 -0.1 N/A

% of years SA entitlement restricted 43.0 0.0 -0.9 0.0 N/A N/A 0.0 0.0 N/A N/A N/A N/A N/A N/A N/A 0.0 0.0 0.0 0.0 0.0 0.0 0.9 0.0 0.0 0.0 N/A

Maximum SA restriction (GL) 1031.8 2.8 9.3 1.2 N/A N/A 0.0 0.0 N/A N/A N/A N/A N/A N/A N/A 0.0 1.0 -0.7 -0.9 0.8 -0.5 -4.3 0.2 0.3 -1.2 N/A

% of months Lower Darling restricted 100.0 0.0 0.0 0.0 N/A N/A 0.0 0.0 N/A N/A N/A N/A N/A N/A N/A 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 N/A

Economic gross margin ($m/year)

Value of irrigation 940.3 0.2 0.1 -0.1 N/A N/A 0.0 0.0 N/A N/A N/A N/A N/A N/A N/A 0.0 0.4 0.5 0.5 0.5 -1.6 5.2 0.3 0.4 0.5 N/A

Value of hydro electricity 10.6 0.0 0.0 0.0 N/A N/A 0.0 0.0 N/A N/A N/A N/A N/A N/A N/A 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 N/A

Hume recreation value 2.8 0.0 0.0 0.0 N/A N/A 0.0 0.0 N/A N/A N/A N/A N/A N/A N/A 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 N/A

Flooding benefit -1.6 0.0 0.0 0.0 N/A N/A 0.0 0.0 N/A N/A N/A N/A N/A N/A N/A 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 N/A

Salinity benefit -92.4 -0.1 0.4 0.0 N/A N/A 0.0 -0.2 N/A N/A N/A N/A N/A N/A N/A 0.0 -0.1 -0.1 -0.1 -0.1 0.0 0.1 0.0 0.0 0.1 N/A

Total economic benefit 859.6 0.1 0.4 -0.1 N/A N/A 0.0 -0.2 N/A N/A N/A N/A N/A N/A N/A 0.0 0.3 0.4 0.4 0.4 -1.6 5.2 0.3 0.4 0.6 N/A

Mean annual flow (GL/year)

Euston 6340.7 -2.2 1.4 0.2 N/A N/A 0.2 0.9 N/A N/A N/A N/A N/A N/A N/A 0.0 -3.6 -5.3 -8.6 -9.3 1.3 8.7 -1.8 -1.8 -3.0 N/A

Flow to South Australia 6250.3 -2.5 -0.4 -0.3 N/A N/A 0.2 1.0 N/A N/A N/A N/A N/A N/A N/A 0.0 -3.4 -5.5 -8.8 -9.3 1.1 5.2 -1.6 -2.0 -3.4 N/A

Barrages 4469.8 -2.7 -0.5 -0.2 N/A N/A 0.1 0.9 N/A N/A N/A N/A N/A N/A N/A 0.0 -3.6 -5.6 -8.7 -9.2 0.5 4.7 -1.7 -2.2 -3.5 N/A

Average Salinities (EC)

Yarrawonga 63.1 0.0 0.1 0.0 N/A N/A 0.0 -0.1 N/A N/A N/A N/A N/A N/A N/A 0.0 0.0 0.0 0.0 0.0 0.1 0.1 0.0 0.0 0.0 N/A

Torrumbarry 116.5 0.2 0.1 -0.2 N/A N/A -0.1 -0.2 N/A N/A N/A N/A N/A N/A N/A 0.0 0.2 0.3 0.5 0.5 0.9 3.6 0.1 0.2 0.3 N/A

Swan Hill 269.4 0.8 -0.7 0.2 N/A N/A -0.4 -0.9 N/A N/A N/A N/A N/A N/A N/A 0.0 0.9 1.8 2.6 2.6 0.0 1.7 0.5 1.0 1.5 N/A

Stevens Weir 84.8 -0.1 0.1 -0.1 N/A N/A 0.0 -0.2 N/A N/A N/A N/A N/A N/A N/A 0.0 0.0 -0.2 -0.1 -0.1 0.2 0.3 0.0 0.0 0.0 N/A

Kyalite 327.1 -2.7 3.3 -3.5 N/A N/A 0.9 2.1 N/A N/A N/A N/A N/A N/A N/A 0.0 -3.6 -5.1 -5.6 -5.8 4.6 11.7 -1.5 -3.2 -4.0 N/A

Wakool Junction 275.8 0.5 0.0 0.1 N/A N/A -0.1 -0.3 N/A N/A N/A N/A N/A N/A N/A 0.0 -0.1 0.0 0.3 0.3 0.2 2.5 0.0 -0.2 -0.3 N/A

Red Cliffs 307.0 0.4 0.4 0.1 N/A N/A 0.2 0.0 N/A N/A N/A N/A N/A N/A N/A 0.0 -0.2 -0.3 0.0 0.0 -0.6 0.7 -0.1 -0.3 -0.4 N/A

Merbein 329.7 0.5 0.6 0.1 N/A N/A 0.2 0.2 N/A N/A N/A N/A N/A N/A N/A 0.0 -0.3 -0.4 0.0 -0.1 -0.9 0.0 -0.1 -0.4 -0.6 N/A

Lock 9 359.4 0.4 1.2 0.5 N/A N/A 0.4 0.4 N/A N/A N/A N/A N/A N/A N/A 0.0 -0.3 -0.6 -0.3 -0.3 -1.7 -1.0 -0.2 -0.4 -0.9 N/A



Indicator

Op

tio

n 1

Op

tio

n 2

Op

tio

n 3

a

Op

tio

n 3

b

Op

tio

n 4

a

Op

tio

n 4

b

Op

tio

n 5

a

Op

tio

n 5

b

Op

tio

n 6

a

Op

tio

n 6

b

Op

tio

n 6

c

Op

tio

n 7

a

Op

tio

n 7

b

Op

tio

n 7

c

Op

tio

n 7

d

Op

tio

n 1

0

Op

tio

n 1

1

Op

tio

n 1

2a

Op

tio

n 1

2b

Op

tio

n 1

2c

Op

tio

n 1

3

Op

tio

n 1

5

Op

tio

n 1

6a

Op

tio

n 1

6b

Op

tio

n 1

6c

Op

tio

n 1

7

Renmark 404.2 0.4 1.4 -0.1 N/A N/A 0.1 0.0 N/A N/A N/A N/A N/A N/A N/A 0.0 -0.3 -0.7 -0.4 -0.4 -1.0 -0.2 -0.2 -0.4 -0.9 N/A

Berri 445.4 0.4 1.6 -0.3 N/A N/A 0.1 0.0 N/A N/A N/A N/A N/A N/A N/A 0.0 -0.3 -0.8 -0.5 -0.4 -1.2 -0.6 -0.2 -0.4 -0.9 N/A

Morgan 520.7 0.4 0.5 -0.4 N/A N/A 0.2 0.3 N/A N/A N/A N/A N/A N/A N/A 0.0 -0.3 -0.9 -0.6 -0.7 -1.3 -1.4 -0.2 -0.5 -1.3 N/A

Murray Bridge 553.2 0.4 0.2 -0.8 N/A N/A 0.2 0.3 N/A N/A N/A N/A N/A N/A N/A 0.0 0.4 0.5 1.0 1.0 -0.6 -1.0 0.0 0.0 -0.6 N/A

Milang 695.8 0.4 0.5 0.1 N/A N/A -0.2 -0.6 N/A N/A N/A N/A N/A N/A N/A 0.0 0.5 0.7 0.9 1.1 0.2 0.7 0.2 0.3 0.3 N/A

Weir 32 447.0 0.0 3.1 1.0 N/A N/A 0.0 0.0 N/A N/A N/A N/A N/A N/A N/A 0.0 0.3 -0.5 -0.2 0.0 -0.7 1.7 -0.1 0.0 0.0 N/A

Burtundy 455.8 1.2 4.1 1.0 N/A N/A 0.0 0.0 N/A N/A N/A N/A N/A N/A N/A 0.0 1.5 0.3 1.2 0.7 -0.2 2.2 0.6 0.7 0.3 N/A

Anabranch outflow 931.5 -5.7 -5.5 5.9 N/A N/A 0.0 0.0 N/A N/A N/A N/A N/A N/A N/A 0.0 0.2 0.9 0.8 0.4 0.5 -9.5 0.3 0.4 0.3 N/A

System losses (GL/year)

Hume evaporation loss 75.2 0.0 -1.2 0.0 N/A N/A 0.0 0.0 N/A N/A N/A N/A N/A N/A N/A 0.0 0.1 0.1 0.1 0.1 0.0 -0.1 0.0 0.0 0.1 N/A

Dartmouth evaporation loss 0.5 0.0 0.0 0.0 N/A N/A 0.0 0.0 N/A N/A N/A N/A N/A N/A N/A 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 N/A

Lake Victoria evaporation loss 131.1 0.0 0.5 0.1 N/A N/A 0.0 0.0 N/A N/A N/A N/A N/A N/A N/A 0.0 0.1 0.1 0.1 0.0 0.1 0.4 0.0 0.1 0.1 N/A

Menindee Lakes evaporation loss 389.6 -0.1 -0.1 0.8 N/A N/A 0.0 0.0 N/A N/A N/A N/A N/A N/A N/A 0.0 -0.2 -0.2 -0.1 -0.1 -0.1 0.6 -0.1 -0.1 -0.1 N/A

Upper River Murray loss 1026.0 0.1 -0.6 -0.2 N/A N/A 0.0 0.0 N/A N/A N/A N/A N/A N/A N/A 0.0 -3.4 -5.5 -5.1 -4.9 -4.2 -13.0 -1.8 -3.6 -5.4 N/A

Lower Darling/Anabranch loss 251.9 0.0 -0.4 0.1 N/A N/A 0.0 0.0 N/A N/A N/A N/A N/A N/A N/A 0.0 -0.1 0.0 0.0 -0.1 0.0 -0.1 0.0 -0.1 0.0 N/A

South Australian losses 1122.2 0.0 0.1 0.0 N/A N/A 0.0 0.0 N/A N/A N/A N/A N/A N/A N/A 0.0 0.0 0.0 -0.1 -0.1 0.0 0.1 0.0 0.0 0.0 N/A

Total system loss 2996.7 0.0 -1.5 0.8 N/A N/A 0.0 0.0 N/A N/A N/A N/A N/A N/A N/A 0.0 -3.4 -5.4 -5.2 -5.1 -4.2 -12.1 -1.8 -3.8 -5.3 N/A

Darling system

Tandou diversion (GL/year) 72.2 -0.1 0.3 -0.5 N/A N/A 0.0 0.0 N/A N/A N/A N/A N/A N/A N/A 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 N/A

Anabranch replenishment (GL/year) 45.8 0.0 0.1 -0.1 N/A N/A 0.0 0.0 N/A N/A N/A N/A N/A N/A N/A 0.0 0.0 -0.1 -0.1 -0.1 0.0 -0.1 0.0 -0.1 -0.1 N/A

Value of hydro electricity ($m/year)

Dartmouth 5.8 0.0 0.0 0.0 N/A N/A 0.0 0.0 N/A N/A N/A N/A N/A N/A N/A 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 N/A

Hume 4.8 0.0 0.0 0.0 N/A N/A 0.0 0.0 N/A N/A N/A N/A N/A N/A N/A 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 N/A

Total hydro electricity value 10.6 0.0 0.0 0.0 N/A N/A 0.0 0.0 N/A N/A N/A N/A N/A N/A N/A 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 N/A

Irrigation value ($m/year)

New South Wales 247.90 0.09 0.05 -0.07 N/A N/A 0.00 0.00 N/A N/A N/A N/A N/A N/A N/A 0.00 0.26 0.34 0.47 0.45 0.16 -0.22 0.20 0.21 0.36 N/A

Victoria 425.51 -0.02 -0.04 0.05 N/A N/A 0.00 0.00 N/A N/A N/A N/A N/A N/A N/A 0.00 0.05 0.05 0.00 0.01 -1.90 5.30 0.02 0.03 0.05 N/A

South Australia 266.85 0.08 0.04 -0.06 N/A N/A 0.00 0.00 N/A N/A N/A N/A N/A N/A N/A 0.00 0.08 0.07 0.04 0.06 0.17 0.08 0.07 0.13 0.09 N/A

Total irrigation value 940.26 0.15 0.06 -0.08 N/A N/A 0.00 0.00 N/A N/A N/A N/A N/A N/A N/A 0.00 0.40 0.46 0.50 0.52 -1.57 5.16 0.29 0.37 0.50 N/A

Flooding

Flooding cost ($m/year) 1.6 0.0 0.0 0.0 N/A N/A 0.0 0.0 N/A N/A N/A N/A N/A N/A N/A 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 N/A

Salinity

Salinity cost ($m/year) 92.4 0.1 -0.4 0.0 N/A N/A 0.0 0.2 N/A N/A N/A N/A N/A N/A N/A 0.0 0.1 0.1 0.1 0.1 0.0 -0.1 0.0 0.0 -0.1 N/A

Other

Darling River loss (GL/year) 356.5 -0.1 0.0 -0.1 N/A N/A 0.0 0.0 N/A N/A N/A N/A N/A N/A N/A 0.0 -0.1 0.0 0.0 -0.1 -0.1 0.0 0.0 -0.1 0.0 N/A

Anabranch environmental flows (GL/year) 13.5 0.0 0.0 0.0 N/A N/A 0.0 0.0 N/A N/A N/A N/A N/A N/A N/A 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 N/A

Anabranch return flow (GL/year) 118.2 0.0 0.3 -0.1 N/A N/A 0.0 0.0 N/A N/A N/A N/A N/A N/A N/A 0.0 0.0 0.0 0.0 0.0 0.0 0.1 0.0 0.0 0.0 N/A

Mean other NSW general security allocation (EOY) 87.9 -0.1 0.0 0.1 N/A N/A 0.0 0.0 N/A N/A N/A N/A N/A N/A N/A 0.0 0.2 0.2 0.2 0.2 0.0 0.0 0.2 0.1 0.2 N/A

MIL allocation volume (GL) (EOY) 1460.9 1.4 0.3 -0.5 N/A N/A 0.0 0.0 N/A N/A N/A N/A N/A N/A N/A 0.0 2.2 3.0 3.7 3.7 1.0 -3.3 1.3 2.0 2.9 N/A

Mean NSW total allocation (GL) (EOY) 2185.7 1.1 0.3 -0.4 N/A N/A 0.0 0.0 N/A N/A N/A N/A N/A N/A N/A 0.0 2.9 3.8 5.0 4.7 1.4 -3.0 2.0 2.4 3.8 N/A

NSW Murray diversion (Jul – Jun) (GL) 1787.7 0.8 -0.3 -0.2 N/A N/A 0.0 0.0 N/A N/A N/A N/A N/A N/A N/A 0.0 2.5 3.4 4.5 4.3 1.4 -2.3 1.7 2.0 3.4 N/A

* Option 15- these changes reflect the diversion of water around the Barmah Choke through the Murray-Goulbrun Interconnector. Additional water is diverted into the Interconnector Channel at Yarrawonga Weir, however this water is returned

to the River Murray via Broken Creek and the Goulburn River. The increase in diversions is countered by the increase in tributary inflows. There is no net change in water availability in the River Murray System.

** Option 13- the increase in tributary inflows from Broken Creek is the result of the increased diversions through the Murray Valley and Broken Creek system. There is no net change in water availability in the River Muray System.



Appendix E Scenario modelling results summary

Table F- 1: Scenario modelling results summary- shortfalls downstream of Yarrawonga Weir.

Shortfalls

Op

tio

n 1

2030d

ry O

pti

on

1

2030d

ry O

pti

on

5b

2030d

ry O

pti

on

6c

2030d

ry O

pti

on

12b

2030d

ry O

pti

on

15

Po

stT

LM

Op

tio

n 1

Po

stT

LM

Op

tio

n 5

b

Po

stT

LM

Op

tio

n 6

c

Po

stT

LM

Op

tio

n 1

2b

Po

stT

LM

Op

tio

n 1

5

Po

stT

LM

2030d

ry

Op

tio

n 1

Po

stT

LM

2030d

ry

Op

tio

n 5

b

Po

stT

LM

2030d

ry

Op

tio

n 6

c

Po

stT

LM

2030d

ry

Op

tio

n 1

2b

Po

stT

LM

2030d

ry

Op

tio

n 1

5


Number (total) 13 13 14 9 13 9 6 8 3 13 6 9 8 5 10 8

Number (type I- peak demand) 12 14 15 8 13 8 8 8 3 11 6 11 11 6 9 6


1 -1 -1 1 0 1 -2 0 0 2 0 -2 -3 -1 1 2

Average volume (GL) 2.4 0.9 0.8 0.5 1.9 1.8 2.0 2.3 0.5 3.3 2.5 1.8 1.3 1.2 2.7 3.2

Average duration (days) 3.4 1.8 1.7 1.0 3.0 2.8 3.5 3.6 2.0 4.4 3.8 2.8 2.5 1.4 4.6 5.1


Number 8 11 11 3 7 6 7 6 5 8 3 13 12 3 11 8



1 4 4 -1 0 0 1 1 4 3 2 3 1 1 2 -1




Number 7 6 6 3 4 3 14 14 7 7 12 4 7 0 1 5



5 2 2 3 1 1 7 6 4 1 6 1 3 0 0 3



Total shortfalls

Number (total) 28 30 31 15 24 18 27 28 15 28 21 26 27 8 22 21



7 5 5 3 1 2 6 7 8 6 8 2 1 0 3 4



Table F- 2: Scenario modelling results summary- unseasonal flooding of the Barmah-Millewa Forest.

Unseasonal Flooding

Op

tio

n 1

2030d

ry O

pti

on

1

2030d

ry O

pti

on

5b

2030d

ry O

pti

on

6c

*

2030d

ry O

pti

on

12b

2030d

ry O

pti

on

15

Po

stT

LM

Op

tio

n 1

Po

stT

LM

Op

tio

n 5

b

Po

stT

LM

Op

tio

n 6

c*

Po

stT

LM

Op

tio

n 1

2b

Po

stT

LM

Op

tio

n 1

5

Po

stT

LM

2030d

ry O

pti

on

1

Po

stT

LM

2030d

ry O

pti

on

5b

Po

stT

LM

2030d

ry O

pti

on

6c

*

Po

stT

LM

2030d

ry O

pti

on

12b

Po

stT

LM

2030d

ry O

pti

on

15

Total years of unseasonal flooding 63 39 15 63 38 35 77 38 63 72 70 54 23 63 49 46

Total years of moderate unseasonal flooding 33 19 4 33 18 22 43 16 33 34 36 31 13 33 30 29

Total years of more severe unseasonal flooding 29 16 9 29 15 9 27 20 29 25 28 19 9 29 13 14

Proportion of wet years for each side of the forest 40% 22% 10% 40% 21% 18% 43% 25% 40% 37% 40% 30% 14% 40% 25% 25%

* Effect on unseasonal flooding for these options was not modelled and has been set to the values modelled for Option 1.



Table F- 3: Option modelling results summary- Barmah Choke Study specific indicators. Note results the results for Option 1 under each reference run represent the absolute results, results for all other options indicate change from Option 1.

Indicator

Pre

TL

M O

pti

on

1

Comparison with Pre TLM Option 1

20

30

dry

Op

tio

n 1

Comparison with 2030 dry Option 1

Po

stT

LM

Op

tio

n 1

Comparison with Post TLM

Po

stT

LM

20

30

dry

Op

tio

n 1

Comparison with Post TLM 2030 dry Option 1

20

30

dry

Op

tio

n 1

Po

stT

LM

Op

tio

n 1

Po

stT

LM

20

30

dry

Op

tio

n 1

20

30

dry

Op

tio

n 5

b

20

30

dry

Op

tio

n 6

c

20

30

dry

Op

tio

n 1

2b

20

30

dry

Op

tio

n 1

5

Po

stT

LM

Po

stT

LM

Po

stT

LM

Po

stT

LM

Po

stT

LM

20

30

dry

Op

tio

n 5

b

Po

stT

LM

20

30

dry

Op

tio

n 6

c

Po

stT

LM

20

30

dry

Op

tio

n 1

2b

Po

stT

LM

20

30

dry

Op

tio

n 1

5

Op

tio

n 5

b

Op

tio

n 6

c

Op

tio

n

12

b

Op

tio

n 1

5

Forest losses (15th

December to 30th April)

Total loss from Yarrawonga to Barmah (GL/year) 147.9 -31.9 7.5 -29.6 116.0 -1.2 N/A -1.8 -4.5 155.4 -3.7 N/A -5.8 -4.5 118.3 -2.8 N/A -3.3 -5.2

Barmah Forest loss (GL/year) 132.1 -39.0 10.1 -35.8 93.0 -1.6 N/A -2.6 -4.8 142.1 -4.3 N/A -8.4 -5.3 96.3 -3.6 N/A -5.5 -6.4

Allocations

Years with 100% allocation for general security entitlement (NSW) 71.3% -0.5 0.0 -0.4 26.1% 0.0 N/A 0.0 0.0 73.0% 0.0 N/A 0.0 0.0 28.7% 0.0 N/A 0.0 0.0

Average allocation for general security entitlement (NSW) 85.6 -27.7 1.9 -25.5 57.8 0.0 N/A 0.0 -0.5 87.5 0.0 N/A -0.3 -0.6 60.1 0.0 N/A 0.0 -0.8

Years with 100% allocation for high reliability water shares (Victoria) 98.2% -0.1 0.0 -0.1 85.0% 0.0 N/A 0.0 0.0 98.2% 0.0 N/A 0.0 0.0 85.0% 0.0 N/A 0.0 0.0

Years with 100% allocation for low reliability water shares (Victoria) 77.0% -0.5 0.0 -0.4 25.7% 0.0 N/A 0.0 0.0 81.4% 0.0 N/A 0.0 0.0 32.7% 0.0 N/A 0.0 0.0

Average allocation for high + low reliability water shares (Victoria) 182.0 -52.9 2.2 -48.9 129.0 0.0 N/A -0.4 1.0 184.2 0.0 N/A -0.9 1.2 133.1 0.0 N/A -2.0 3.3

Beneficial flooding of the Barmah-Millewa Forest

% of years with a medium/large flood of 25,000 ML/day at Yarrawonga for >= 2 months 16.8% -0.1 0.0 -0.1 3.5% 0.0 N/A 0.0 0.0 17.7% 0.0 N/A 0.0 0.0 3.5% 0.0 N/A 0.0 0.0

Maximum duration with no medium/large flood (years) 21 17.0 0.0 17.0 38 0.0 N/A 0.0 0.0 21 0.0 N/A -7.0 -7.0 38 0.0 N/A 0.0 0.0

% of years with a small flood of 18,000 ML/day at Yarrawonga for >= 3 months 13.3% -0.1 0.0 -0.1 3.5% 0.0 N/A 0.0 0.0 15.9% 0.0 N/A 0.0 0.0 3.5% 0.0 N/A 0.0 0.0

Maximum duration with no small flood (years) 21 17.0 0.0 17.0 38 0.0 N/A 0.0 0.0 21 0.0 N/A 0.0 0.0 38 0.0 N/A 0.0 0.0

Beneficial flooding of Koondrook/Gunbower Wetlands

% of years with a medium/large flood of 35,000 ML/day at Torrumbarry for >= 3 months 4.4% 0.0 0.0 0.0 1.8% 0.0 N/A 0.0 0.0 6.2% 0.0 N/A 0.0 0.0 2.7% 0.0 N/A 0.0 0.0

Maximum duration with no medium/large flood (years) 34 26.0 0.0 4.0 60 0.0 N/A 0.0 0.0 34 0.0 N/A 0.0 0.0 38 0.0 N/A 0.0 0.0

% of years with a small flood of 25,000 ML/day at Torrumbarry for >= 3 months 15.0% -0.1 0.0 -0.1 2.7% 0.0 N/A 0.0 0.0 18.6% 0.0 N/A 0.0 0.0 2.7% 0.0 N/A 0.0 0.0

Maximum duration with no small flood (years) 20 18.0 -1.0 18.0 38 0.0 N/A 0.0 0.0 19 0.0 N/A 1.0 0.0 38 0.0 N/A 0.0 0.0

Beneficial flooding of Hattah Lakes

% of years with a medium/large flood of 75,000 ML/day at Euston for >= 1 month 9.7% -0.1 0.0 -0.1 0.9% 0.0 N/A 0.0 0.0 10.6% 0.0 N/A 0.0 0.0 1.8% 0.0 N/A 0.0 0.0

Maximum duration with no medium/large flood (years) 21 39.0 0.0 39.0 60 0.0 N/A 0.0 0.0 21 0.0 N/A 0.0 0.0 60 0.0 N/A 0.0 -22.0

% of years with a small flood of 45,000 ML/day at Euston for >= 3 months 12.4% -0.1 0.0 -0.1 2.7% 0.0 N/A 0.0 0.0 13.3% 0.0 N/A 0.0 0.0 2.7% 0.0 N/A 0.0 0.0


Beneficial flooding of Chowilla/Lindsay-Wallpolla

% of years with a medium/large flood of 80,000 ML/day at SA border for >= 3 months 4.4% 0.0 0.0 0.0 0.9% 0.0 N/A 0.0 0.0 4.4% 0.0 N/A 0.0 0.0 0.9% 0.0 N/A 0.0 0.0

Maximum duration with no medium/large flood (years) 37 23.0 0.0 23.0 60 0.0 N/A 0.0 0.0 37 0.0 N/A 0.0 0.0 60 0.0 N/A 0.0 0.0

% of years with a small flood of 50,000 ML/day at SA border for >= 3 months 13.3% -0.1 0.0 -0.1 2.7% 0.0 N/A 0.0 0.0 14.2% 0.0 N/A 0.0 0.0 2.7% 0.0 N/A 0.0 0.0




Unregulated flows

Average flow to SA in excess of entitlement (GL/year) 4435.9 -2599.5

306.1 -2429.6

1836.5 0.8 N/A -3.6 6.9 4742.0 1.8 N/A -3.3 7.0 2006.3 1.6 N/A -0.6 15.8

% of years where flows to SA < 1,850 GL/year 94.7% -0.2 0.0 -0.1 76.1% 0.0 N/A 0.0 0.0 96.5% 0.0 N/A 0.0 0.0 83.2% 0.0 N/A 0.0 0.0

Lake Victoria target levels

% of years Lake Victoria level of the last day of February meets target (≤26.5 m AHD) 97.9% 0.0 0.0 0.0 100.0% 0.0 N/A 0.0 0.0 95.8% 0.0 N/A 0.0 0.0 93.3% 0.0 N/A 0.0 0.0

Proportion of time (years) target not applied due to conditional rules 57.5% 0.3 0.0 0.3 87.6% 0.0 N/A 0.0 0.0 57.5% 0.0 N/A 0.0 0.0 86.7% 0.0 N/A 0.0 0.0

% of years Lake Victoria level of the last day of March meets target (≤25.6 m AHD) 94.0% 0.1 0.0 0.1 100.0% 0.0 N/A 0.0 -0.1 94.0% 0.0 N/A 0.0 0.0 100.0% 0.0 N/A 0.0 -0.1


% of years Lake Victoria level of the last day of April meets target (≤24.6 m AHD) 90.2% -0.1 0.0 -0.1 76.9% 0.0 N/A 0.0 0.0 88.9% 0.0 N/A 0.0 0.0 80.0% 0.0 N/A 0.0 0.1


% of time (days) Lake Victoria level is > 25.5 m AHD in May (target = minimal) 7.7% -0.1 0.0 0.1 1.1% 0.0 N/A 0.0 0.0 7.4% 0.0 N/A 0.0 0.0 13.9% 0.0 N/A 0.1 0.0

Proportion of time (days) target not applied due to conditional rules 50.9% 0.4 -0.1 0.3 86.8% 0.0 N/A 0.0 0.0 45.6% 0.0 N/A 0.0 0.0 85.1% 0.0 N/A 0.0 0.0

% of time (days) during winter and spring where lake level is ≥ 27.0 m AHD in (target = minimal)

28.0% 0.0 0.0 0.0 27.3% 0.0 N/A 0.0 0.0 24.3% 0.0 N/A 0.0 0.0 28.1% 0.0 N/A 0.0 0.0

Werai Forest flooding

% of years of undesirable flooding 43.0% -0.1 0.1 -0.1 30.7% 0.0 N/A 0.2 -0.1 51.8% -0.1 N/A 0.3 0.0 37.7% 0.0 N/A 0.3 0.0

Undesirable exceedences- other locations

% of years capacity downstream of Hume Reservoir exceeded (25,000 ML/day, Jan – Apr) 2.6% 0.0 0.0 0.0 0.0% 0.0 N/A 0.0 0.0 3.5% 0.0 N/A 0.0 0.0 0.9% 0.0 N/A 0.0 0.0

% of years capacity of Edward offtake exceeded (1,600 ML/day Jan – Apr) 45.6% -0.2 -0.1 -0.2 24.6% 0.0 N/A 0.0 -0.1 39.5% 0.0 N/A 0.0 0.0 22.8% 0.0 N/A 0.0 0.0

% of days capacity of Gulpa offtake exceeded (350 ML/day, Feb – Apr) 27.4% -0.1 0.0 -0.1 21.6% 0.0 N/A 0.0 0.0 26.7% 0.0 N/A -0.1 -0.1 21.8% 0.0 N/A -0.1 0.0

Hydropower generation

Average annual power generation at Dartmouth Reservoir (GWh) 287.3 -138.2 5.9 -117.7 149.1 0.0 N/A -1.2 0.2 293.2 0.0 N/A -2.9 -5.1 169.6 0.0 N/A -6.8 -11.9

Recreational water levels (Jan – Apr)

Lake Mulwala Average water level (m AHD) 124.8 -0.1 0.0 -0.1 124.7 -0.4 N/A 0.0 0.0 124.9 -0.4 N/A 0.0 0.0 124.7 -0.4 N/A 0.0 0.0

Median water level (m AHD) 124.8 -0.1 0.0 -0.1 124.8 -0.5 N/A 0.0 0.0 124.9 -0.5 N/A 0.0 0.0 124.8 -0.5 N/A 0.0 0.0

Minimum water level (m AHD) 123.9 -1.6 -0.9 -4.0 122.3 0.0 N/A 0.0 -2.2 123.0 -0.1 N/A -0.8 -0.9 119.9 0.0 N/A 0.8 -4.4

95th

percentile water level (m AHD 124.6 -0.1 0.0 -0.2 124.5 -0.5 N/A 0.0 -0.1 124.6 -0.5 N/A 0.0 0.0 124.4 -0.4 N/A 0.0 -0.2

Euston Weir Average water level (m AHD) 47.7 0.0 0.0 0.0 47.7 0.0 N/A 0.0 0.0 47.7 0.0 N/A 0.0 0.0 47.7 0.0 N/A 0.0 0.0

Median water level (m AHD) 47.7 0.0 0.0 0.0 47.7 0.0 N/A 0.0 0.0 47.7 0.0 N/A 0.0 0.0 47.7 0.0 N/A 0.0 0.0

Minimum water level (m AHD) 46.9 -1.4 -0.3 -1.4 45.5 0.0 N/A 0.0 0.0 46.6 0.0 N/A 0.0 -0.1 45.5 0.0 N/A 0.0 0.0

95th

percentile water level (m AHD 47.7 0.0 0.0 0.0 47.7 0.0 N/A 0.0 0.0 47.7 0.0 N/A 0.0 0.0 47.7 0.0 N/A 0.0 0.0



Table F- 4: Option modelling results summary- MDBA standard indicators. Note results the results for Option 1 under each reference run represent the absolute results, results for all other options indicate change from Option 1.

Indicator

Pre

TL

M O

pti

on

1

Comparison with Pre TLM Option 1

20

30

dry

Op

tio

n 1

Comparison with 2030 dry Option 1

Po

stT

LM

Op

tio

n 1

Comparison with Post TLM

Po

stT

LM

20

30

dry

Op

tio

n 1

Comparison with Post TLM 2030 dry Option 1

20

30

dry

Op

tio

n 1

Po

stT

LM

Op

tio

n 1

Po

stT

LM

20

30

dry

Op

tio

n 1

20

30

dry

Op

tio

n 5

b

20

30

dry

Op

tio

n 6

c

20

30

dry

Op

tio

n 1

2b

20

30

dry

Op

tio

n 1

5

Po

stT

LM

Po

stT

LM

Po

stT

LM

Po

stT

LM

Po

stT

LM

20

30

dry

Op

tio

n 5

b

Po

stT

LM

20

30

dry

Op

tio

n 6

c

Po

stT

LM

20

30

dry

Op

tio

n 1

2b

Po

stT

LM

20

30

dry

Op

tio

n 1

5

Op

tio

n 5

b

Op

tio

n 6

c

Op

tio

n 1

2b

Op

tio

n 1

5

SRA Hydrology Index

Original Murray-Lower Darling Index 0.588 -0.078 0.021 -0.066 0.510 0.000 N/A 0.000 -0.001 0.609 -0.001 N/A 0.000 -0.081 0.522 -0.001 N/A 0.004 -0.001

Zone 1 U/s Hume 0.763 0.010 0.016 0.012 0.773 0.000 N/A 0.000 0.001 0.779 0.000 N/A -0.006 0.031 0.776 0.000 N/A -0.001 0.001

Zone 2 Hume to Yarrawonga 0.738 0.017 0.002 0.007 0.755 -0.005 N/A 0.000 0.001 0.740 -0.011 N/A 0.003 -0.010 0.745 0.000 N/A 0.009 0.002

Zone 3 Yarrawonga to Wakool Junction 0.605 -0.103 0.013 -0.092 0.502 0.000 N/A 0.003 -0.002 0.619 0.000 N/A 0.005 -0.079 0.513 -0.001 N/A 0.010 -0.002

Zone 4 Wakool to Wentworth 0.615 -0.085 0.015 -0.077 0.529 0.001 N/A -0.001 -0.003 0.630 0.000 N/A -0.001 -0.079 0.538 -0.001 N/A 0.003 -0.005

Zone 5 Wentworth to Lock 3 0.524 -0.088 0.027 -0.073 0.436 0.000 N/A -0.001 0.002 0.551 0.000 N/A -0.003 -0.116 0.451 -0.001 N/A 0.000 0.000

Zone 6 Lower Darling 0.444 -0.011 0.010 -0.008 0.433 0.000 N/A 0.002 0.001 0.454 0.000 N/A 0.002 -0.060 0.436 0.000 N/A 0.000 -0.002

Zone 7 Lock 3 to Lakes 0.510 -0.108 0.032 -0.093 0.402 0.000 N/A 0.000 0.001 0.542 0.000 N/A -0.004 -0.127 0.417 0.000 N/A 0.002 0.000

Zone 8 Lower Lakes 0.358 -0.128 0.130 -0.018 0.230 0.000 N/A 0.000 0.001 0.488 0.001 N/A -0.001 -0.151 0.339 -0.001 N/A 0.000 0.000

Morgan salinity (EC)

Average Morgan salinity 520.7 241.0 -22.5 212.3 761.7 0.3 N/A 1.7 -2.2 498.2 1.3 N/A -4.0 60.2 733.0 2.9 N/A 2.4 5.5

95th

percentile Morgan salinity 804 563 -41 499 1367 1 N/A 30 -5 763 6 N/A -4 73 1303 25 N/A -12 21

Average annual diversions (GL/year)

NSW Murray diversions 1787.7 -373.3 -87.1 -427.6 1414.4 0.0 N/A 1.1 -10.0 1700.6 0.0 N/A -2.5 -148.7 1360.2 0.0 N/A 3.2 -14.6

Victorian Murray diversions 1736.1 -170.9 -68.8 -197.8 1565.1 0.0 N/A -1.8 54.0 1667.3 0.0 N/A -3.0 -91.6 1538.2 0.0 N/A -17.2 51.7

SA diversions 707.2 -80.4 -40.9 -116.1 626.7 0.0 N/A -0.1 0.5 666.3 0.0 N/A 0.4 -27.3 591.1 0.0 N/A -3.8 -2.9

Lower Darling diversions 132.9 -35.7 -59.3 -75.5 97.2 0.0 N/A 0.1 0.2 73.7 0.0 N/A -0.6 -14.9 57.4 0.0 N/A 0.0 0.5

Total diversions 4363.9 -660.3 -256.1 -817.0 3703.5 0.0 N/A -0.7 44.7 4107.8 0.0 N/A -5.7 -282.4 3546.9 0.0 N/A -17.7 34.7

SA country towns diversions 48.0 -6.0 0.0 -5.9 42.0 0.0 N/A 0.0 0.0 47.9 0.0 N/A 0.0 -1.1 42.1 0.0 N/A -0.2 -0.1

Metropolitan Adelaide diversions 99.1 -1.5 0.0 -1.4 97.6 0.0 N/A 0.0 0.0 99.0 0.0 N/A 0.0 -0.7 97.7 0.0 N/A -0.1 -0.1

Other SA diversions 560.1 -73.0 -40.8 -108.8 487.2 0.0 N/A -0.1 0.4 519.4 0.0 N/A 0.5 -25.5 451.3 0.0 N/A -3.5 -2.7

Average cap adjustments (GL/year)

NSW Murray -2.4 0.0 -62.5 -51.3 -2.4 0.0 N/A 0.0 0.0 -64.9 0.0 N/A -1.9 -1.5 -53.7 0.0 N/A -0.7 -1.0

Victorian Murray 74.4 0.0 -48.0 -28.4 74.4 0.0 N/A 0.0 0.0 26.4 0.0 N/A 0.5 8.1 46.0 0.0 N/A 0.9 -1.3

South Australia 32.4 0.0 -30.3 -25.3 32.4 0.0 N/A 0.0 0.0 2.1 0.0 N/A -0.7 -0.8 7.0 0.0 N/A 0.5 -0.2

Lower Darling 14.1 -4.6 1.3 -4.6 9.5 0.0 N/A -0.3 0.2 15.4 0.0 N/A -0.1 -5.0 9.5 0.0 N/A 0.2 0.5

Total cap adjustment 118.6 -4.6 -139.6 -109.7 114.0 0.0 N/A -0.3 0.2 -21.0 0.0 N/A -2.2 0.9 8.9 0.0 N/A 0.9 -2.0

Tributary inflows (GL/year)

Murrumbidgee 1224.6 -498.5 61.4 -437.2 726.1 0.0 N/A 0.0 0.0 1286.0 0.0 N/A -0.1 -499.2 787.3 0.0 N/A -0.5 0.2

Billabong Creek 307.1 -95.2 0.0 -95.2 212.0 0.0 N/A 0.0 0.0 307.1 0.0 N/A 0.0 -95.2 212.0 0.0 N/A 0.0 0.0



Menindee Lakes inflow 1721.1 -532.6 0.0 -532.6 1188.5 0.0 N/A 0.0 0.0 1721.1 0.0 N/A 0.0 -532.6 1188.5 0.0 N/A 0.0 0.0

Goulburn River 1450.2 -620.8 86.4 -593.7 829.4 0.0 N/A 0.0 50.0 1536.7 0.0 N/A 3.3 -681.9 856.5 0.0 N/A -1.1 48.5

Broken Creek 178.2 -48.6 0.0 -48.6 129.6 0.0 N/A 0.0 48.0 178.2 0.0 N/A 0.0 -48.7 129.6 0.0 N/A 0.0 48.0

Campaspe River 151.2 -98.2 -2.3 -98.2 53.0 0.0 N/A 0.0 0.0 148.9 0.0 N/A 0.0 -95.9 53.0 0.0 N/A 0.0 0.0

Loddon flow at Appin South 57.6 -27.8 3.2 -27.8 29.8 0.0 N/A 0.0 0.0 60.8 0.0 N/A 0.0 -31.1 29.8 0.0 N/A 0.0 0.0

Total tributary flow 5090.1 -1921.7

148.8 -1833.4

3168.3 0.0 N/A 0.0 98.1 5238.9 0.0 N/A 3.2 -1984.4

3256.6 0.0 N/A -1.6 96.7

Allocations

Mean NSW high security allocation 99.1 -2.3 0.1 -1.6 96.8 0.0 N/A -0.1 0.1 99.2 0.0 N/A -0.1 -0.6 97.6 0.0 N/A -0.1 -0.2

Mean other NSW general security allocation 81.6 -36.1 1.9 -34.5 45.5 0.0 N/A 0.1 -0.4 83.5 0.0 N/A -0.5 -13.1 47.1 0.0 N/A -0.5 -0.9

Minimum other NSW general security allocation 1.7 -1.5 -0.4 -1.6 0.1 0.0 N/A 0.0 0.0 1.3 0.0 N/A 1.9 -0.7 0.1 0.0 N/A 0.0 0.0

Minimum Victorian February allocation 13.0 -13.0 11.0 -13.0 0.0 0.0 N/A 0.0 0.0 24.0 0.0 N/A -4.0 -24.0 0.0 0.0 N/A 0.0 0.0

% of years Victorian allocation < 100% 2.6 13.2 0.0 13.2 15.8 0.0 N/A 0.0 0.9 2.6 0.0 N/A 0.0 9.6 15.8 0.0 N/A -0.9 -0.9

Mean Victorian February allocation 180.5 -52.6 2.3 -48.5 127.9 0.0 N/A -0.4 1.0 182.8 0.0 N/A -0.9 -26.7 132.0 0.0 N/A -2.0 3.4

% of years SA entitlement restricted 43.0 46.5 -3.5 42.1 89.5 0.0 N/A 0.9 0.9 39.5 0.0 N/A 0.0 30.7 85.1 0.0 N/A 0.0 4.4

Maximum SA restriction (GL) 1031.8 133.4 34.6 141.8 1165.2 0.0 N/A -0.3 -1.6 1066.5 0.0 N/A -19.6 36.8 1173.6 0.0 N/A -15.7 -17.0

% of months Lower Darling restricted 100.0 0.0 0.0 0.0 100.0 0.0 N/A 0.0 0.0 100.0 0.0 N/A 0.0 0.0 100.0 0.0 N/A 0.0 0.0

Economic gross margin ($m/year)

Value of irrigation 940.3 -114.5 -38.1 -140.7 825.7 0.0 N/A -0.1 4.9 902.2 0.0 N/A -0.3 -37.3 799.6 0.0 N/A -2.3 3.4

Value of hydro electricity 10.6 -4.5 0.3 -4.0 6.0 0.0 N/A 0.0 0.0 10.9 0.0 N/A -0.1 -1.3 6.6 0.0 N/A -0.1 -0.2

Hume recreation value 2.8 -0.9 0.1 -0.8 1.9 0.0 N/A 0.0 0.0 2.9 0.0 N/A 0.0 -0.4 2.0 0.0 N/A 0.0 0.0

Flooding benefit -1.6 1.4 -0.2 1.4 -0.2 0.0 N/A 0.0 0.0 -1.7 0.0 N/A 0.1 0.4 -0.2 0.0 N/A 0.0 0.0

Salinity benefit -92.4 -50.5 3.6 -47.0 -143.0 -0.2 N/A -0.2 0.3 -88.8 -0.3 N/A 0.5 -14.9 -139.5 -0.8 N/A -0.8 -0.9

Total economic benefit 859.6 -169.1 -34.2 -191.1 690.5 -0.2 N/A -0.4 5.2 825.4 -0.3 N/A 0.1 -53.4 668.5 -0.8 N/A -3.3 2.3

Mean annual flow (GL/year)

Euston 6340.7 -2465.2

280.4 -2299.7

3875.4 0.9 N/A -6.0 10.7 6621.1 1.8 N/A -7.0 -1763.1

4040.9 0.9 N/A -2.4 20.7

Flow to South Australia 6250.3 -2644.4

307.2 -2459.6

3605.9 0.8 N/A -5.2 8.5 6557.5 1.9 N/A -3.9 -1900.6

3790.7 1.0 N/A -3.4 18.0

Barrages 4469.8 -2657.4

356.4 -2420.6

1812.4 0.8 N/A -3.8 7.2 4826.2 1.9 N/A -2.9 -1852.8

2049.2 1.1 N/A 1.2 20.8

Average Salinities (EC)

Yarrawonga 63.1 2.4 -0.1 2.2 65.5 -0.2 N/A 0.1 0.2 63.1 -0.1 N/A 0.2 0.3 65.3 -0.2 N/A 0.1 0.3

Torrumbarry 116.5 2.6 3.1 3.0 119.0 -0.2 N/A 0.7 4.2 119.6 -0.3 N/A 1.1 -5.6 119.5 -0.2 N/A 0.9 4.8

Swan Hill 269.4 14.3 7.8 29.3 283.7 0.0 N/A 3.2 1.8 277.2 -1.2 N/A 3.7 6.5 298.7 0.3 N/A 3.7 11.9

Stevens Weir 84.8 10.0 -0.7 9.6 94.8 -0.4 N/A -0.3 0.8 84.1 -0.1 N/A -0.1 2.9 94.4 -0.3 N/A -0.1 0.7

Kyalite 327.1 63.4 -16.0 62.9 390.5 2.0 N/A -11.3 14.2 311.1 2.6 N/A -10.4 22.3 390.0 4.0 N/A -9.9 10.5

Wakool Junction 275.8 31.1 3.4 41.0 306.8 0.1 N/A 0.8 2.9 279.2 -0.3 N/A -0.2 13.9 316.8 0.7 N/A 0.5 6.5

Red Cliffs 307.0 45.4 -1.8 45.8 352.4 0.2 N/A 0.3 1.0 305.3 0.3 N/A -1.3 16.9 352.8 0.7 N/A 0.6 5.7

Merbein 329.7 56.1 -4.5 53.0 385.8 0.5 N/A 0.4 -0.1 325.2 0.6 N/A -1.5 20.5 382.7 1.0 N/A 1.0 5.9

Lock 9 359.4 53.3 -6.9 54.0 412.7 0.4 N/A 1.1 0.3 352.5 1.0 N/A -2.7 15.2 413.4 1.7 N/A 0.3 5.0

Renmark 404.2 96.3 -8.8 96.5 500.5 -0.7 N/A 0.1 1.3 395.4 0.6 N/A -3.7 29.3 500.7 1.1 N/A -0.9 3.7

Berri 445.4 135.2 -12.8 129.3 580.6 -0.9 N/A 0.7 0.2 432.6 0.7 N/A -3.7 39.7 574.7 1.1 N/A -1.5 3.9



Morgan 520.7 241.0 -22.5 212.3 761.7 0.3 N/A 1.7 -2.2 498.2 1.3 N/A -4.0 60.2 733.0 2.9 N/A 2.4 5.5

Murray Bridge 553.2 285.2 -26.3 254.4 838.4 -0.7 N/A -0.8 -1.0 526.9 0.7 N/A -3.7 83.1 807.6 15.1 N/A 6.8 10.4

Milang 695.8 1016.8 -24.7 926.2 1712.6 -1.5 N/A 14.1 6.7 671.1 -0.1 N/A 0.1 230.6 1621.9 0.3 N/A 17.2 18.4

Weir 32 447.0 25.2 20.0 27.4 472.2 0.0 N/A 0.2 -0.2 467.0 0.0 N/A 1.5 1.0 474.3 0.0 N/A 0.6 1.7

Burtundy 455.8 26.9 25.9 37.2 482.7 0.0 N/A -0.9 0.4 481.6 0.0 N/A 2.6 4.2 492.9 0.0 N/A 0.4 1.1

Anabranch outflow 931.5 1735.8 -338.6 411.6 2667.4 0.0 N/A -0.8 -350.6 592.9 0.0 N/A -0.5 205.0 1343.1 0.0 N/A -2.5 22.2

System losses (GL/year)

Hume evaporation loss 75.2 3.7 2.4 6.7 79.0 0.0 N/A 0.1 0.1 77.6 0.0 N/A -0.1 -7.6 82.0 0.0 N/A -0.4 -0.2

Dartmouth evaporation loss 0.5 8.8 0.0 9.7 9.3 0.0 N/A 0.0 0.0 0.6 0.0 N/A 0.0 0.2 10.2 0.0 N/A -0.1 -0.5

Lake Victoria evaporation loss 131.1 27.5 -1.1 27.3 158.6 0.0 N/A 0.3 0.7 130.0 0.0 N/A 0.3 -2.5 158.4 0.0 N/A 1.2 0.8

Menindee Lakes evaporation loss 389.6 -56.3 0.5 -60.8 333.3 0.0 N/A -0.6 0.6 390.1 0.0 N/A 0.6 -81.4 328.8 0.0 N/A 2.1 1.9

Upper River Murray loss 1026.0 -223.0 11.9 -206.0 803.0 0.0 N/A -2.8 -11.0 1037.9 0.0 N/A 1.0 -164.6 820.0 0.0 N/A 1.8 -14.3

Lower Darling/Anabranch loss 251.9 -83.8 8.3 -75.8 168.1 0.0 N/A 0.2 0.2 260.2 0.0 N/A -0.3 -92.2 176.1 0.0 N/A 0.0 0.2

South Australian losses 1122.2 98.1 -4.7 85.2 1220.3 0.0 N/A -1.2 0.6 1117.6 0.0 N/A -1.3 -18.7 1207.4 -0.1 N/A -0.3 0.1

Total system loss 2996.7 -225.2 17.3 -213.8 2771.5 0.0 N/A -4.1 -8.9 3014.0 0.0 N/A 0.3 -366.8 2782.9 -0.1 N/A 4.2 -12.0

Darling system

Tandou diversion (GL/year) 72.2 -22.6 -15.8 -33.2 49.6 0.0 N/A 0.1 0.1 56.4 0.0 N/A -0.6 -14.3 39.0 0.0 N/A 0.0 0.5

Anabranch replenishment (GL/year) 45.8 -14.6 -45.8 -45.8 31.2 0.0 N/A 0.0 0.1 0.0 0.0 N/A 0.0 0.0 0.0 0.0 N/A 0.0 0.0

Value of hydro electricity ($m/year)

Dartmouth 5.8 -2.7 0.1 -2.3 3.0 0.0 N/A 0.0 0.0 5.9 0.0 N/A -0.1 -0.7 3.4 0.0 N/A -0.1 -0.2

Hume 4.8 -1.8 0.2 -1.7 3.0 0.0 N/A 0.0 0.0 5.0 0.0 N/A 0.0 -0.6 3.1 0.0 N/A 0.0 0.0

Total hydro electricity value 10.6 -4.5 0.3 -4.0 6.0 0.0 N/A 0.0 0.0 10.9 0.0 N/A -0.1 -1.3 6.6 0.0 N/A -0.1 -0.2

Irrigation value ($m/year)

New South Wales 247.90 -63.47 -12.12 -72.00 184.43 0.00 N/A 0.11 -0.91 235.78 0.00 N/A -0.40 -17.79 175.90 0.00 N/A 0.25 -1.45

Victoria 425.51 -31.53 -8.18 -35.11 393.98 0.00 N/A -0.17 5.64 417.32 0.00 N/A -0.12 -11.13 390.40 0.00 N/A -1.76 5.66

South Australia 266.85 -19.54 -17.77 -33.57 247.31 0.00 N/A -0.05 0.17 249.08 0.00 N/A 0.21 -8.36 233.28 0.00 N/A -0.80 -0.84

Total irrigation value 940.26 -114.54

-38.07 -140.68

825.73 0.00 N/A -0.11 4.90 902.19 0.00 N/A -0.31 -37.28 799.58 0.00 N/A -2.31 3.37

Flooding

Flooding cost ($m/year) 1.6 -1.4 0.2 -1.4 0.2 0.0 N/A 0.0 0.0 1.7 0.0 N/A -0.1 -0.4 0.2 0.0 N/A 0.0 0.0

Salinity

Salinity cost ($m/year) 92.4 50.5 -3.6 47.0 143.0 0.2 N/A 0.2 -0.3 88.8 0.3 N/A -0.5 14.9 139.5 0.8 N/A 0.8 0.9

Other

Darling River loss (GL/year) 356.5 -129.9 10.6 -122.5 226.6 0.0 N/A 0.1 0.2 367.2 0.0 N/A -0.2 -133.0 234.0 0.0 N/A 0.1 0.5

Anabranch environmental flows (GL/year) 13.5 -6.6 3.2 -2.4 6.9 0.0 N/A 0.3 0.1 16.7 0.0 N/A -1.0 -2.2 11.1 0.0 N/A -0.3 -0.9

Anabranch return flow (GL/year) 118.2 -52.7 5.5 -49.1 65.4 0.0 N/A 0.2 0.1 123.7 0.0 N/A -0.9 -43.0 69.1 0.0 N/A -0.2 -0.6

Mean other NSW general security allocation (EOY) 87.9 -25.5 1.2 -23.7 62.4 0.0 N/A 0.0 -0.6 89.1 0.0 N/A -0.2 -8.1 64.2 0.0 N/A -0.1 -0.8

MIL allocation volume (GL) (EOY) 1460.9 -421.1 -98.5 -469.6 1039.8 0.0 N/A 1.3 -7.6 1362.4 0.0 N/A -2.7 -138.5 991.3 0.0 N/A 2.1 -11.1

Mean NSW total allocation (GL) (EOY) 2185.7 -519.1 -30.2 -508.7 1666.6 0.0 N/A 0.9 -10.4 2155.6 0.0 N/A -3.2 -173.9 1677.0 0.0 N/A 3.7 -14.7

NSW Murray diversion (Jul – Jun) (GL) 1787.7 -373.3 -87.1 -427.6 1414.4 0.0 N/A 1.1 -10.0 1700.6 0.0 N/A -2.5 -148.7 1360.2 0.0 N/A 3.2 -14.6



Appendix F Financial analysis of options

Murray Darling Basin AuthorityBarmah Choke Study: Financial Analysis of Options

Primary Developer: Mani Manivasakan, Daniel Besley

General Cover Notes:

Undertaken as part of the Barmah Choke assessment process

Go to Table of Contents

Table of ContentsBarmah Choke Study: Financial Analysis of Options

Section & Sheet Titles Page

3

4

5

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

Total Pages: 26

n. Option 15: Murray Goulburn interconnector (2000ML/d)

h. Option 7b: 16 GL Storage at The Drop on Mulwala Canal (Option 3A from previous study)

i. Option 10a: Victorian Forest Channels (Kynmer Creek Route)

j. Option 10b: Victorian Forest Channels (Gulf Creek Route)

m. Option 13: Increased escape capacity to Broken Creek

k. Option 11: Increased diversion through the Wakool River

l. Option 12: Increased escape capacity to the Edward River

g. Option 7a: 11 GL Storage at The Drop on Mulwala Canal (Option 2A from previous study)

1. Cost Summaries and Risk Costs Analysis

a. Summary results

b. Monte Carlo Modelling Results

2. Cost Assumptions

a. Option 4: Mildura Weir

d. Option 6a: Euston Weir - Raise the minimum operating level of Euston Weir by 0.5 m to 48.1 m AHD

e. Option 6b: Euston Weir - Lower the minimum operating level of Euston Weir by 1.5 m to 46.1 m AHD

f. Option 6c: Euston Weir - Raise the minimum operating level of Euston Weir by 0.5 m to 48.1 m AHD and Lower the minimum operating level of Euston Weir by 1.5 m to 46.1 m AHD

Go to Cover Sheet

b. Option 5a: Lower operating level Lake Mulwala by 100 mm

c. Option 5b: Lower operating level Lake Mulwala by 500 mm

Cost Summaries and Risk Costs AnalysisSection 1.Barmah Choke Study: Financial Analysis of Options


DB_08_BCS_Options_Costing_Model.xlsx

Results_SC

Printed: 4:08 PM on 4/02/2011 Page 3 of 26

Summary results

Barmah Choke Study: Financial Analysis of Options

Capital Cost

(base estimate, incl

contingency)

Capital Cost

(incl, contingency and

risk - 90th percentile)

Operating cost

(base estimate)

Operating Cost

(incl, contingency and

risk - 90th percentile)

Present Value

20 years @6%

(base estimate)

Present Value

20 years @6%

(90th percentile)

Option 4: Mildura Weir $ 1.68 m $ 1.91 m - - $ 1.68 m $ 1.91 m

Option 5a: Lower operating level Lake Mulwala by 100 mm $ 2.62 m $ 2.89 m $ 0.07 m $ 0.07 m $ 3.40 m $ 3.71 m

Option 5b: Lower operating level Lake Mulwala by 500 mm $ 8.10 m $ 9.18 m $ 0.27 m $ 0.28 m $ 11.23 m $ 12.44 m

Option 6a: Euston Weir - Raise the minimum operating level

of Euston Weir by 0.5 m to 48.1 m AHD$ 0.83 m $ 0.95 m - - $ 0.83 m $ 0.95 m

Option 6b: Euston Weir - Lower the minimum operating level

of Euston Weir by 1.5 m to 46.1 m AHD$ 1.99 m $ 2.24 m - - $ 1.99 m $ 2.24 m

Option 6c: Euston Weir - Raise the minimum operating level

of Euston Weir by 0.5 m to 48.1 m AHD and Lower the $ 2.26 m $ 2.62 m - - $ 2.26 m $ 2.62 m

Option 7a: 11 GL Storage at The Drop on Mulwala Canal

(Option 2A from previous study)$ 56.37 m $ 63.08 m $ 1.27 m $ 1.42 m $ 70.91 m $ 79.31 m

Option 7b: 16 GL Storage at The Drop on Mulwala Canal

(Option 3A from previous study)$ 70.14 m $ 78.66 m $ 1.49 m $ 1.67 m $ 87.23 m $ 97.81 m

Option 10a: Victorian Forest Channels (Kynmer Creek

Route)$ 90.08 m $ 109.56 m $ 0.66 m $ 0.86 m $ 97.66 m $ 119.46 m

Option 10b: Victorian Forest Channels (Gulf Creek Route) $ 57.14 m $ 68.65 m $ 0.46 m $ 0.59 m $ 62.45 m $ 75.36 m

Option 11: Increased diversion through the Wakool River $ 1.93 m $ 2.15 m $ 0.42 m $ 0.42 m $ 6.75 m $ 6.97 m

Option 12: Increased escape capacity to the Edward River $ 2.55 m $ 3.01 m $ 0.42 m $ 0.42 m $ 7.37 m $ 7.83 m

Option 13: Increased escape capacity to Broken Creek $ 16.54 m $ 18.48 m $ 0.34 m $ 0.37 m $ 20.43 m $ 22.71 m

Option 15: Murray Goulburn interconnector (2000ML/d) $ 370.35 m $ 424.86 m $ 2.09 m $ 2.62 m $ 394.27 m $ 454.92 m

A 1 GL storage at The Drop (quarry site) $ 5.00 m $ 0.10 m $ 6.15 m

A 5 GL storage at The Drop (quarry site) $ 10.00 m $ 0.20 m $ 12.29 m

Increasing the capacity of the Edward River escape by

1,000 ML/day $ 6.50 m $ 0.13 m $ 7.99 m



Summ_results_BO


Monte Carlo Modelling ResultsBarmah Choke Study: Financial Analysis of Options

Forecast: Capex: Option 4- Mildura Weir

Percentiles: Forecast values

50 $1,710,639.62 90 $1,912,489.79

Forecast: Capex: Option 5a: Lower operating level Lake Mulwala by 100 mm Forecast: Opex: Option 5a: Lower operating level Lake Mulwala by 100 mm

Percentiles: Forecast values Percentiles: Forecast values

50 $2,779,095.96 50 $68,750.07 90 $2,885,125.53 90 $72,261.07



Model_results_BO



Forecast: Capex: Option 5b: Lower operating level Lake Mulwala by 500 mm Forecast: Opex: Option 5b: Lower operating level Lake Mulwala by 500 mm

Forecast: Capex: Option 5b: Lower operating level Lake Mulwala by 500 mm (cont'd) Percentiles: Forecast values

50 $276,003 Percentiles: Forecast values 90 $284,246

50 $8,686,639.19 90 $9,181,640.37

Option 6a: Euston Weir - Raise the minimum operating level of Euston Weir by 0.5 m to 48.1 m AHD


50 $844,301.14 90 $949,084.36


Model_results_BO



Option 6b: Euston Weir - Lower the minimum operating level of Euston Weir by 1.5 m to 46.1 m AHD


50 $2,065,278.85 90 $2,241,010.34

Option 6c: Euston Weir - Raise the minimum operating level of Euston Weir by 0.5 m to 48.1 m AHD and Lower the minimum operating level of Euston Weir by 1.5 m to 46.1 m AHD


50 $2,370,971.11 90 $2,619,974.33


Model_results_BO



Option 7a: 11 GL Storage at The Drop on Mulwala Canal (Option 2A from previous study) Forecast: Opex: Option 7a: 11 ML Storage at The Drop on Mulwala Canal (Option 2A from previous study)


50 $60,532,033.68 50 ###########90 $63,077,829.87 90 ###########

Forecast: Capex: Option 7b: 16 ML Storage at The Drop on Mulwala Canal (Option 3A from previous study) Forecast: Opex: Option 7b: 16 ML Storage at The Drop on Mulwala Canal (Option 3A from previous study)


50 $75,248,195.88 50 $1,538,341.02 90 $78,663,338.14 90 $1,669,453.89


Model_results_BO



Forecast: Capex: Option 10a -Victorian Forest Channels (Kynmer Creek Route) Forecast: Opex: Option 10a -Victorian Forest Channels (Kynmer Creek Route)


50 $100,929,012 50 $724,476.66 90 $109,562,854 90 $862,661.44

Forecast: Capex: Option 10b -Victorian Forest Channels (Gulf Creek Route) Forecast: Opex: Option 10b -Victorian Forest Channels (Gulf Creek Route)


50 $63,603,201 Percentiles: Forecast values

90 $68,651,193 50 $502,658.11 90 $585,314.19


Model_results_BO



Forecast: Capex: Option 11- increased diversion through the Wakool River


50 $2,018,903.90 90 $2,154,909.22

Forecast: Capex: Option 12- Increased escape capacity to the Edward River


50 $2,685,758.83 90 $3,009,924.12


Model_results_BO



Forecast: Capex: Option 13: Increased escape capacity to Broken Creek Forecast: Opex: Option 13: Increased escape capacity to Broken Creek


50 $17,698,036.18 50 $346,060.25 90 $18,481,124.81 90 $368,511.42

Forecast: Capex: Option 15: Murray Goulburn interconnector (2000ML/d) Forecast: Opex: Option 15: Murray Goulburn interconnector (2000ML/d)


50 $397,152,697.69 Percentiles: Forecast values

90 $424,860,828.82 50 $2,195,317.20 90 $2,620,614.12


Model_results_BO


Cost AssumptionsSection 2.Barmah Choke Study: Financial Analysis of Options

Section Cover Notes:

[Insert section cover note 1]





Assumptions_SC


BA Option 4: Mildura Weir


Design and Administration Costs (%) 20.0%

Contingency (%) 40.0%

CAPITAL COSTS

Cost item Assumptions / Sources Min Expected Max Min Expected Max Min Expected Max

Extension of Irrigators Pumps $ - $ - $ - Pumps 1 1 1 Item $ 750,000.00 $ 900,000.00 $ 1,200,000.00 $ 750,000 $ 900,000 $ 1,200,000

Mooring Bouys and Jetties $ - $ - $ - Works 1 1 1 Item $ 75,000.00 $ 100,000.00 $ 125,000.00 $ 75,000 $ 100,000 $ 125,000

TOTAL RAW CAPITAL COST 825,000$ 1,000,000$ 1,325,000$

Design and Administration Costs (%) 165,000$ 200,000$ 265,000$

Contingency (%) 396,000$ 480,000$ 636,000$

TOTAL CAPITAL COST 1,386,000$ 1,680,000$ 2,226,000$

ANNUAL COSTS


NA $ - $ - $ - TOTAL RAW ANNUAL COST -$ -$ -$

Contingency (%) -$ -$ -$

TOTAL ANNUAL COST -$ -$ -$

Cost Analysis



Cost AnalysisQuantity UNIT Price or Rates Cost Range


Option_4_BA

Printed: 4:08 PM on 4/02/2011 Page: 13 of 26

BA Option 5a: Lower operating level Lake Mulwala by 100 mm




CAPITAL COSTS


Remove 8-Mile Weir Regulator 1 1 1 Item $ 22,500.00 $ 25,000.00 $ 32,000.00 $ 22,500 $ 25,000 $ 32,000 Site Establishment 1 1 1 Item $ 45,000.00 $ 50,000.00 $ 65,000.00 $ 45,000 $ 50,000 $ 65,000 Remove and dispose existing structure 2400 2400 3000 m3 $ 14.00 $ 16.00 $ 18.00 $ 33,600 $ 38,400 $ 54,000 Re-instate Channel 1 1 1 Item $ 135,000.00 $ 150,000.00 $ 200,000.00 $ 135,000 $ 150,000 $ 200,000 Ultrasonic Flow Measurement Device

Channel Remodelling $ - $ - $ - Channel Deepening and disposing 30000 30000 36000 m3 $ 7.20 $ 8.00 $ 10.00 $ 216,000 $ 240,000 $ 360,000 Excavation for clay lining (600 mm) 6500 6500 9000 m3 $ 2.00 $ 2.20 $ 3.00 $ 13,000 $ 14,300 $ 27,000 450 mm clay lining 5000 5000 7500 m3 $ 14.00 $ 16.00 $ 18.00 $ 70,000 $ 80,000 $ 135,000 150 mm crush rock lining 1700 1700 2300 m3 $ 54.00 $ 60.00 $ 78.00 $ 91,800 $ 102,000 $ 179,400 Miscellaneous items (incl. Environmental

clearances, fence removal & reinstatement, silt

fences)

3400 3400 4500 m $ 8.00 $ 9.00 $ 12.00 $ 27,200 $ 30,600 $ 54,000

Modify Irrigation Supply $ - $ - $ - Extend pump intakes 10 10 12 No. $ 9,000.00 $ 10,000.00 $ 13,000.00 $ 90,000 $ 100,000 $ 156,000 Replace water wheels with pumps 2 2 3 No. $ 22,500.00 $ 25,000.00 $ 32,000.00 $ 45,000 $ 50,000 $ 96,000 O&M for pumps in lieu of wheels 2 2 3 No. $ 9,000.00 $ 10,000.00 $ 13,000.00 $ 18,000 $ 20,000 $ 39,000

Bridge Works $ - $ - $ - Beaching and pipe works 3 3 4 No. $ 36,000.00 $ 40,000.00 $ 52,000.00 $ 108,000 $ 120,000 $ 208,000

Offtake Works $ - $ - $ - Modify fish passage structure 1 1 1 No. $ 360,000.00 $ 400,000.00 $ 500,000.00 $ 360,000 $ 400,000 $ 500,000

Modify Log Barrier $ - $ - $ - Remove half the log barriers 1 1 1 No. $ 36,000.00 $ 40,000.00 $ 52,000.00 $ 36,000 $ 40,000 $ 52,000 Provide a new floating log barrier upstream 1 1 1 No. $ 72,000.00 $ 80,000.00 $ 100,000.00 $ 72,000 $ 80,000 $ 100,000

Tree Stump Removal $ - $ - $ - Not required 0 0 $ - $ - $ - $ -

Edge Treatment $ - $ - $ - Not required 0 0 $ - $ - $ - $ -

Jetty Extension $ - $ - $ - Not required 0 0 $ - $ - $ - $ -

Navigational Channel Works $ - $ - $ - Confirm new area suitable for navigation 200 200 250 hours $ 90.00 $ 100.00 $ 130.00 $ 18,000 $ 20,000 $ 32,500

$ - $ - $ - TOTAL RAW CAPITAL COST 1,401,100$ 1,560,300$ 2,289,900$


Contingency (%) 672,528$ 748,944$ 1,099,152$


ANNUAL COSTS


Maintance Cost 1% of capital 1 1 1 Item $ 16,396.80 $ 18,259.92 $ 27,331.92 $ 16,397 $ 18,260 $ 27,332 Operational Cost no change to existing 1 1 1 Item $ - $ - $ - $ - $ - $ - Power station - loss of income 1 1 1 Item $ 38,100.00 $ 38,100.00 $ 38,100.00 $ 38,100 $ 38,100 $ 38,100

$ - $ - $ - TOTAL RAW ANNUAL COST 54,497$ 56,360$ 65,432$

Contingency (%) 10,899$ 11,272$ 13,086$

TOTAL ANNUAL COST 65,396$ 67,632$ 78,518$

Cost Analysis





Option_5a_BA


BA Option 5b: Lower operating level Lake Mulwala by 500 mm




CAPITAL COSTS


Remove 8-Mile Weir Regulator 1 1 1 Item $ 22,500.00 $ 25,000.00 $ 32,000.00 $ 22,500 $ 25,000 $ 32,000 Site Establishment 1 1 1 Item $ 45,000.00 $ 50,000.00 $ 65,000.00 $ 45,000 $ 50,000 $ 65,000 Remove and dispose existing structure 2400 2400 3000 m3 $ 14.00 $ 16.00 $ 18.00 $ 33,600 $ 38,400 $ 54,000 Re-instate Channel 1 1 1 Item $ 135,000.00 $ 150,000.00 $ 200,000.00 $ 135,000 $ 150,000 $ 200,000 Ultrasonic Flow Measurement Device

Channel RemodellingChannel Deepening and disposing 170000 170000 220000 m3 $ 7.20 $ 8.00 $ 10.00 $ 1,224,000 $ 1,360,000 $ 2,200,000 Excavation for clay lining (600 mm) 29000 29000 37000 m3 $ 2.00 $ 2.20 $ 3.00 $ 58,000 $ 63,800 $ 111,000 450 mm clay lining 22500 22500 29000 m3 $ 14.00 $ 16.00 $ 18.00 $ 315,000 $ 360,000 $ 522,000 150 mm crush rock lining 7500 7500 10000 m3 $ 54.00 $ 60.00 $ 78.00 $ 405,000 $ 450,000 $ 780,000 Miscellaneous items (incl. Environmental

clearances, fence removal & reinstatement, silt

fences)

13600 13600 18000 m $ 8.00 $ 9.00 $ 12.00 $ 108,800 $ 122,400 $ 216,000

Modify Irrigation SupplyExtend pump intakes 10 10 12 No. $ 9,000.00 $ 10,000.00 $ 13,000.00 $ 90,000 $ 100,000 $ 156,000 Replace water wheels with pumps 2 2 3 No. $ 22,500.00 $ 25,000.00 $ 32,000.00 $ 45,000 $ 50,000 $ 96,000 O&M for pumps in lieu of wheels 2 2 3 No. $ 9,000.00 $ 10,000.00 $ 13,000.00 $ 18,000 $ 20,000 $ 39,000 Suction work for irrigators from Lake 15 15 20 No. $ 4,500.00 $ 5,000.00 $ 6,500.00 $ 67,500 $ 75,000 $ 130,000

Bridge WorksBeaching and pipe works 11 11 14 No. $ 36,000.00 $ 40,000.00 $ 52,000.00 $ 396,000 $ 440,000 $ 728,000

Offtake WorksMinor modifications to existing structure 1 1 1 No. $ 270,000.00 $ 300,000.00 $ 360,000.00 $ 270,000 $ 300,000 $ 360,000 Modify fish passage structure 1 1 1 No. $ 360,000.00 $ 400,000.00 $ 500,000.00 $ 360,000 $ 400,000 $ 500,000

Modify Log BarrierRemove half the log barriers 1 1 1 No. $ 36,000.00 $ 40,000.00 $ 52,000.00 $ 36,000 $ 40,000 $ 52,000 Provide a new floating log barrier upstream 1 1 1 No. $ 72,000.00 $ 80,000.00 $ 100,000.00 $ 72,000 $ 80,000 $ 100,000

Tree Stump RemovalIdentification, lowering and securing of lowered

logs1000 1000 1300

person

hours $ 67.50 $ 75.00 $ 95.00 $ 67,500 $ 75,000 $ 123,500

Edge Treatmentretaining walls to effected lakeside properties 4000 4000 5200 m2 $ 45.00 $ 50.00 $ 65.00 $ 180,000 $ 200,000 $ 338,000

Jetty Extensionjetty extension 40 40 52 $ 9,000.00 $ 10,000.00 $ 13,000.00 $ 360,000 $ 400,000 $ 676,000

Navigational Channel WorksConfirm new area suitable for navigation 200 200 260 hours $ 90.00 $ 100.00 $ 130.00 $ 18,000 $ 20,000 $ 33,800


Design and Administration Costs (%) 865,380$ 963,920$ 1,502,460$

Contingency (%) 2,076,912$ 2,313,408$ 3,605,904$


ANNUAL COSTS


Maintance Cost 1% of capital 1 1 1 Item $ 33,873.84 $ 37,820.16 $ 58,998.24 $ 33,874 $ 37,820 $ 58,998 Operational Cost no change to existing 1 1 1 Item $ - $ - $ - $ - $ - $ - Power station - loss of income 1 1 1 Item $ 190,100.00 $ 190,100.00 $ 190,100.00 $ 190,100 $ 190,100 $ 190,100


Contingency (%) 44,795$ 45,584$ 49,820$


Cost Analysis





Option_5b_BA


BA Option 6a: Euston Weir - Raise the minimum operating level of Euston Weir by 0.5 m to 48.1 m AHDBarmah Choke Study: Financial Analysis of Options



CAPITAL COSTS


Both Pump Suction Extenstion and Raising of

Pumps $ - $ - $ -

Small Pumps (<=80 mm) 9 14 18 no. $ 7,300.00 $ 8,000.00 $ 10,000.00 $ 65,700.00 $ 112,000.00 $ 180,000.00 Large Pumps(>80mm) 16 20 27 no. $ 9,800.00 $ 10,500.00 $ 13,000.00 $ 156,800.00 $ 210,000.00 $ 351,000.00

$ - $ - $ - Fencing 1 1 1 Item $ 7,500.00 $ 8,000.00 $ 10,000.00 $ 7,500.00 $ 8,000.00 $ 10,000.00

$ - $ - $ - Ruel Lagoon 1 1 1 Item $ - $ - $ - $ -

$ - $ - $ - Dry Lake 1 1 1 Item $ 40,000.00 $ 45,000.00 $ 55,000.00 $ 40,000.00 $ 45,000.00 $ 55,000.00

$ - $ - $ - Lake Bennane 1 1 1 Item $ 7,000.00 $ 8,000.00 $ 10,000.00 $ 7,000.00 $ 8,000.00 $ 10,000.00

$ - $ - $ - Bonyarical Creek 1 1 1 Item $ 10,000.00 $ 110,000.00 $ 140,000.00 $ 10,000.00 $ 110,000.00 $ 140,000.00

$ - $ - $ - Balranald Pump Station 1 1 1 Item $ 2,000.00 $ 2,500.00 $ 3,500.00 $ 2,000.00 $ 2,500.00 $ 3,500.00

$ - $ - $ - Robinvale Pump Station (Urban) Assumed that the pumps are high enough 1 1 1 Item $ - $ - $ - $ - $ - $ -

$ - $ - $ - Robinvale Pump Station (Irrigation) Assumed that the pumps are high enough 1 1 1 Item $ - $ - $ - $ - $ - $ -

$ - $ - $ - TOTAL RAW CAPITAL COST 289,000.00$ 495,500.00$ 749,500.00$

Design and Administration Costs (%) 57,800.00$ 99,100.00$ 149,900.00$

Contingency (%) 138,720.00$ 237,840.00$ 359,760.00$

TOTAL CAPITAL COST 485,520.00$ 832,440.00$ 1,259,160.00$

ANNUAL COSTS







Cost Analysis



Option_6a_BA


BA Option 6b: Euston Weir - Lower the minimum operating level of Euston Weir by 1.5 m to 46.1 m AHDBarmah Choke Study: Financial Analysis of Options



CAPITAL COSTS


Pump Suction Extenstion $ - $ - $ - Small Pumps (<=80 mm) 4 4 6 no. $ 1,800.00 $ 2,000.00 $ 2,500.00 $ 7,200.00 $ 8,000.00 $ 15,000.00 Large Pumps(>80mm) 11 13 16 no. $ 2,300.00 $ 2,500.00 $ 3,000.00 $ 25,300.00 $ 32,500.00 $ 48,000.00

Pumps need LoweringSmall Pumps (<=80 mm) 4 4 6 no. $ 5,500.00 $ 6,000.00 $ 7,500.00 $ 22,000.00 $ 24,000.00 $ 45,000.00 Large Pumps(>80mm) 22 26 32 no. $ 7,500.00 $ 8,000.00 $ 10,000.00 $ 165,000.00 $ 208,000.00 $ 320,000.00

Both Pump Suction Extenstion and Lowering of

PumpsSmall Pumps (<=80 mm) 23 27 32 no. $ 7,300.00 $ 8,000.00 $ 10,000.00 $ 167,900.00 $ 216,000.00 $ 320,000.00 Large Pumps(>80mm) 45 50 60 no. $ 9,800.00 $ 10,500.00 $ 13,000.00 $ 441,000.00 $ 525,000.00 $ 780,000.00

$ - $ - $ - Fencing 1 1 1 Item $ 7,500.00 $ 8,000.00 $ 10,000.00 $ 7,500.00 $ 8,000.00 $ 10,000.00

$ - $ - $ - Dry Lake 1 1 1 Item $ 40,000.00 $ 45,000.00 $ 55,000.00 $ 40,000.00 $ 45,000.00 $ 55,000.00




TOTAL RAW CAPITAL COST 894,900.00$ 1,187,000.00$ 1,746,500.00$


Contingency (%) 429,552.00$ 569,760.00$ 838,320.00$

TOTAL CAPITAL COST 1,503,432.00$ 1,994,160.00$ 2,934,120.00$

ANNUAL COSTS







Cost Analysis



Option_6b_BA


BA Option 6c: Euston Weir - Raise the minimum operating level of Euston Weir by 0.5 m to 48.1 m AHD and Lower the minimum operating level of Euston Weir by 1.5 m to 46.1 m AHD




CAPITAL COSTS


Pump Suction Extenstion $ - $ - $ - Small Pumps (<=80 mm) 1 1 1 no. $ 1,800.00 $ 2,000.00 $ 2,500.00 $ 1,800.00 $ 2,000.00 $ 2,500.00 Large Pumps(>80mm) 16 19 25 no. $ 2,300.00 $ 2,500.00 $ 3,000.00 $ 36,800.00 $ 47,500.00 $ 75,000.00

$ - $ - $ - Pumps need Raising/lowering $ - $ - $ -

Small Pumps (<=80 mm) 14 19 25 no. $ 5,500.00 $ 6,000.00 $ 7,500.00 $ 77,000.00 $ 114,000.00 $ 187,500.00 Large Pumps(>80mm) 15 20 27 no. $ 7,500.00 $ 8,000.00 $ 10,000.00 $ 112,500.00 $ 160,000.00 $ 270,000.00

$ - $ - $ - Both Pump Suction Extenstion and

Raising/Lowering of Pumps $ - $ - $ -

Small Pumps (<=80 mm) 27 31 37 no. $ 7,300.00 $ 8,000.00 $ 10,000.00 $ 197,100.00 $ 248,000.00 $ 370,000.00 Large Pumps(>80mm) 52 57 79 no. $ 9,800.00 $ 10,500.00 $ 13,000.00 $ 509,600.00 $ 598,500.00 $ 1,027,000.00

$ - $ - $ - Fencing 1 1 1 Item $ 7,500.00 $ 8,000.00 $ 10,000.00 $ 7,500.00 $ 8,000.00 $ 10,000.00

$ - $ - $ - Ruel Lagoon 1 1 1 Item $ - $ - $ - $ -

$ - $ - $ - Dry Lake 1 1 1 Item $ 40,000.00 $ 45,000.00 $ 55,000.00 $ 40,000.00 $ 45,000.00 $ 55,000.00




$ - $ - $ - TOTAL RAW CAPITAL COST 1,001,300.00$ 1,343,500.00$ 2,150,500.00$


Contingency (%) 480,624.00$ 644,880.00$ 1,032,240.00$

TOTAL CAPITAL COST 1,682,184.00$ 2,257,080.00$ 3,612,840.00$

ANNUAL COSTS







Cost Analysis



Option_6c_BA


BA Option 7a: 11 GL Storage at The Drop on Mulwala Canal (Option 2A from previous study)




CAPITAL COSTS


EMBANKMENT $ - $ - $ -

Strip topsoil 317306 317306 380767 m3 3 $ 3.00 $ 3.60 $ 951,918 $ 951,918 $ 1,370,761

Excavate foundations 226075 226075 271290 m3 3 $ 3.00 $ 3.60 $ 678,225 $ 678,225 $ 976,644

Zone 1A/1B 989155 989155 1186986 m3 5.5 $ 6.00 $ 7.20 $ 5,440,353 $ 5,934,930 $ 8,546,299

Zone 2B U/S Drain Blanket 26630 26630 31956 m3 30 $ 40.00 $ 67.00 $ 798,900 $ 1,065,200 $ 2,141,052

Zone 2A Chimney Filter 15271 15271 18325 m3 40 $ 45.00 $ 70.00 $ 610,840 $ 687,195 $ 1,282,750

Zone 2A Blanket Filter 57950 57950 69540 m3 30 $ 30.00 $ 32.00 $ 1,738,500 $ 1,738,500 $ 2,225,280

Zone 2B Blanket Filter (+Draincoil) 7070 7070 8484 m3 30 $ 40.00 $ 67.00 $ 212,100 $ 282,800 $ 568,428

Zone 2B Toe Drain Trench,excavate 2.5mx0.5m 7273 7273 8728 m3 40 $ 50.00 $ 70.00 $ 290,920 $ 363,650 $ 610,960 Drainage Manholes 19 19 23 no. 3000 $ 3,000.00 $ 4,500.00 $ 57,000 $ 57,000 $ 103,500

Zone 3 Rip Rap 25779 25779 30935 m3 40 $ 45.00 $ 70.00 $ 1,031,160 $ 1,160,055 $ 2,165,450

Bedding Gravel to Rip Rap 5729 5729 6875 m3 30 $ 40.00 $ 67.00 $ 171,870 $ 229,160 $ 460,625

Topsoil and Seed 198506 198506 238207 m2 0.5 $ 0.50 $ 1.00 $ 99,253 $ 99,253 $ 238,207 Pavement Capping 2545 2545 3054 m3 30 $ 35.00 $ 45.00 $ 76,350 $ 89,075 $ 137,430

Piezometers 19 19 23 no. 300 $ 300.00 $ 500.00 $ 5,700 $ 5,700 $ 11,500

Movement Markers 28 28 34 no. 150 $ 150.00 $ 200.00 $ 4,200 $ 4,200 $ 6,800

GW Drainage Pumps (Prov Sum) 1 1 1 Item 50000 $ 50,000.00 $ 60,000.00 $ 50,000 $ 50,000 $ 60,000

LINER

Rework existing soils 1849404 1849404 2219285 m3 2 $ 2.00 $ 2.60 $ 3,698,808 $ 3,698,808 $ 5,770,141

Zone 1A 1387053 1387053 1664464 m3 5.5 $ 6.00 $ 7.20 $ 7,628,792 $ 8,322,318 $ 11,984,141

Local Scour Protection (lime treat,mesh etc) 1 1 1 Item 100000 $ 100,000.00 $ 150,000.00 $ 100,000 $ 100,000 $ 150,000

INTAKE CANAL AND STRUCTURE

Strip topsoil, stockpile and reuse 3905 3905 4686 m3 9 $ 12.00 $ 20.00 $ 35,145 $ 46,860 $ 93,720

Excavate channel and stockpile 4362 4362 5234 m3 9 $ 12.00 $ 20.00 $ 39,258 $ 52,344 $ 104,680

Place compact fill to canal/canal levees 1589 1589 1907 m3 9 $ 12.00 $ 20.00 $ 14,301 $ 19,068 $ 38,140

Filter fabric 1589 1589 1907 m2 5 $ 5.00 $ 5.00 $ 7,945 $ 7,945 $ 9,535

Quarry and place rock, d50 size 0.2 m 764 764 917 m3 38 $ 45.00 $ 68.00 $ 29,032 $ 34,380 $ 62,356


Reinforced slab & mass concrete 806 806 967 m3 650 $ 800.00 $ 1,400.00 $ 523,900 $ 644,800 $ 1,353,800

Reinforced concrete walls 333 333 400 m3 1050 $ 1,300.00 $ 1,700.00 $ 349,650 $ 432,900 $ 680,000

Reinforced concrete elevated slab 8 8 10 m3 1050 $ 1,300.00 $ 1,700.00 $ 8,400 $ 10,400 $ 17,000

Intake structure E&M equipment 1 1 1 Item $ 920,000.00 $ 920,000.00 $ 1,150,000.00 $ 920,000 $ 920,000 $ 1,150,000

Bridge across Berrigan Road 1 1 1 Item $ 500,000.00 $ 500,000.00 $ 625,000.00 $ 500,000 $ 500,000 $ 625,000

Roadworks Berrigan Road 1 1 1 Item $ 100,000.00 $ 100,000.00 $ 125,000.00 $ 100,000 $ 100,000 $ 125,000

Clay lining for intake canal 3883 3883 4660 m3 10 $ 12.00 $ 15.00 $ 38,830 $ 46,596 $ 69,900

OUTLET STRUCTURE 1


Backfill to structures 2011 2011 2413 m3 11 $ 15.00 $ 20.00 $ 22,121 $ 30,165 $ 48,260

Filter fabric 2600 2600 3120 m2 5 $ 5.00 $ 5.00 $ 13,000 $ 13,000 $ 15,600


Reinforced slab & mass concrete 2126.7 2126.7 2552 m3 650 $ 800.00 $ 1,400.00 $ 1,382,355 $ 1,701,360 $ 3,572,800

Reinforced concrete walls 483.6 483.6 580 1050 $ 1,300.00 $ 1,700.00 $ 507,780 $ 628,680 $ 986,000

Reinforced concrete elevated slab 51.3 51.3 62 1050 $ 1,300.00 $ 1,700.00 $ 53,865 $ 66,690 $ 105,400

Outlet structure E&M equipment (4 pumps) 1 1 1 Item $ 2,280,000.00 $ 2,280,000.00 $ 2,850,000.00 $ 2,280,000 $ 2,280,000 $ 2,850,000

Bridge across Melrose Road 1 1 1 Item $ 200,000.00 $ 200,000.00 $ 250,000.00 $ 200,000 $ 200,000 $ 250,000

Roadworks Melrose Drive 1 1 1 Item $ 50,000.00 $ 50,000.00 $ 62,500.00 $ 50,000 $ 50,000 $ 62,500

TOTAL RAW CAPITAL COST 30,918,501$ 33,555,577$ 51,517,219$

Design and Administration Costs (%) 6,183,700$ 6,711,115$ 10,303,444$

Contingency (%) 14,840,880$ 16,106,677$ 24,728,265$


ANNUAL COSTS


Maintance Cost 1% of capital 1 1 1 Item $ 519,430.82 $ 563,733.69 $ 865,489.28 $ 519,431 $ 563,734 $ 865,489 Power station - loss of income Set to 75% of Option 7b cost 1 1 1 Item $ 142,575.00 $ 142,575.00 $ 142,575.00 $ 142,575 $ 142,575 $ 142,575 Use of Mulwala canal 1 1 1 Item $ 350,000.00 $ 350,000.00 $ 350,000.00 $ 350,000 $ 350,000 $ 350,000

TOTAL RAW ANNUAL COST 1,012,005.82$ 1,056,308.69$ 1,358,064.28$

Contingency (%) 202,401.16$ 211,261.74$ 271,612.86$

TOTAL ANNUAL COST 1,214,406.98$ 1,267,570.43$ 1,629,677.14$

Cost Analysis





Option_7a_BA


BA Option 7b: 16 GL Storage at The Drop on Mulwala Canal (Option 3A from previous study)




CAPITAL COSTS


EMBANKMENT $ - $ - $ -

Strip topsoil 454514 454514 545417 m3 3 $ 3.00 $ 3.60 $ 1,363,542 $ 1,363,542 $ 1,963,501

Excavate foundations 277081 277081 332497 m3 3 $ 3.00 $ 3.60 $ 831,243 $ 831,243 $ 1,196,989

Zone 1A/1B 1210789 1210789 1452947 m3 5.5 $ 6.00 $ 7.20 $ 6,659,340 $ 7,264,734 $ 10,461,218

Zone 2B U/S Drain Blanket 32726 32726 39271 m3 30 $ 40.00 $ 67.00 $ 981,780 $ 1,309,040 $ 2,631,157

Zone 2A Chimney Filter 18700 18700 22440 m3 40 $ 45.00 $ 70.00 $ 748,000 $ 841,500 $ 1,570,800

Zone 2A Blanket Filter 70809 70809 84971 m3 30 $ 30.00 $ 32.00 $ 2,124,270 $ 2,124,270 $ 2,719,072

Zone 2B Blanket Filter (+Draincoil) 8658 8658 10390 m3 30 $ 40.00 $ 67.00 $ 259,740 $ 346,320 $ 696,130

Zone 2B Toe Drain Trench,excavate 2.5mx0.5m 8860 8860 10632 m3 40 $ 50.00 $ 70.00 $ 354,400 $ 443,000 $ 744,240 Drainage Manholes 24 24 29 no. 3000 $ 3,000.00 $ 4,500.00 $ 72,000 $ 72,000 $ 130,500

Zone 3 Rip Rap 21059 21059 25271 m3 40 $ 45.00 $ 70.00 $ 842,360 $ 947,655 $ 1,768,970

Bedding Gravel to Rip Rap 4680 4680 5616 m3 30 $ 40.00 $ 67.00 $ 140,400 $ 187,200 $ 376,272

Topsoil and Seed 266430 266430 319716 m2 0.5 $ 0.50 $ 1.00 $ 133,215 $ 133,215 $ 319,716 Pavement Capping 3117 3117 3740 m3 30 $ 35.00 $ 45.00 $ 93,510 $ 109,095 $ 168,300

Piezometers 23 23 28 no. 300 $ 300.00 $ 500.00 $ 6,900 $ 6,900 $ 14,000

Movement Markers 35 35 42 no. 150 $ 150.00 $ 200.00 $ 5,250 $ 5,250 $ 8,400

GW Drainage Pumps (Prov Sum) 1 1 1 Item 50000 $ 50,000.00 $ 60,000.00 $ 50,000 $ 50,000 $ 60,000

LINER

Rework existing soils 2704114 2704114 3244937 m3 2 $ 2.00 $ 2.60 $ 5,408,228 $ 5,408,228 $ 8,436,836

Zone 1A 2028088 2028088 2433706 m3 5.5 $ 6.00 $ 7.20 $ 11,154,484 $ 12,168,528 $ 17,522,683

Local Scour Protection (lime treat,mesh etc) 1 1 1 Item 100000 $ 100,000.00 $ 150,000.00 $ 100,000 $ 100,000 $ 150,000

INTAKE CANAL AND STRUCTURE

Strip topsoil, stockpile and reuse 3905 3905 4686 m3 9 $ 12.00 $ 20.00 $ 35,145 $ 46,860 $ 93,720


Place compact fill to canal/canal levees 1589 1589 1907 m3 9 $ 12.00 $ 20.00 $ 14,301 $ 19,068 $ 38,140

Filter fabric 1589 1589 1907 m2 5 $ 5.00 $ 5.00 $ 7,945 $ 7,945 $ 9,535



Reinforced slab & mass concrete 806 806 967 m3 650 $ 800.00 $ 1,400.00 $ 523,900 $ 644,800 $ 1,353,800

Reinforced concrete walls 333 333 400 m3 1050 $ 1,300.00 $ 1,700.00 $ 349,650 $ 432,900 $ 680,000

Reinforced concrete elevated slab 8 8 10 m3 1050 $ 1,300.00 $ 1,700.00 $ 8,400 $ 10,400 $ 17,000

Intake structure E&M equipment 1 1 1 Item $ 920,000.00 $ 920,000.00 $ 1,150,000.00 $ 920,000 $ 920,000 $ 1,150,000

Bridge across Berrigan Road 1 1 1 Item $ 500,000.00 $ 500,000.00 $ 625,000.00 $ 500,000 $ 500,000 $ 625,000

Roadworks Berrigan Road 1 1 1 Item $ 100,000.00 $ 100,000.00 $ 125,000.00 $ 100,000 $ 100,000 $ 125,000

Clay lining for intake canal 3883 3883 4660 m3 10 $ 12.00 $ 15.00 $ 38,830 $ 46,596 $ 69,900

OUTLET STRUCTURE 1


Backfill to structures 2011 2011 2413 m3 11 $ 15.00 $ 20.00 $ 22,121 $ 30,165 $ 48,260

Filter fabric 2600 2600 3120 m2 5 $ 5.00 $ 5.00 $ 13,000 $ 13,000 $ 15,600


Reinforced slab & mass concrete 2126.7 2126.7 2552 m3 650 $ 800.00 $ 1,400.00 $ 1,382,355 $ 1,701,360 $ 3,572,800

Reinforced concrete walls 483.6 483.6 580 1050 $ 1,300.00 $ 1,700.00 $ 507,780 $ 628,680 $ 986,000

Reinforced concrete elevated slab 51.3 51.3 62 1050 $ 1,300.00 $ 1,700.00 $ 53,865 $ 66,690 $ 105,400

Outlet structure E&M equipment (4 pumps) 1 1 1 Item $ 2,280,000.00 $ 2,280,000.00 $ 2,850,000.00 $ 2,280,000 $ 2,280,000 $ 2,850,000

Bridge across Melrose Road 1 1 1 Item $ 200,000.00 $ 200,000.00 $ 250,000.00 $ 200,000 $ 200,000 $ 250,000

Roadworks Melrose Drive 1 1 1 Item $ 50,000.00 $ 50,000.00 $ 62,500.00 $ 50,000 $ 50,000 $ 62,500 $ - $ - $ -



Contingency (%) 18,529,092$ 20,039,669$ 30,550,097$


ANNUAL COSTS


Maintance Cost 1% of capital 1 1 1 Item $ 648,518.21 $ 701,388.41 $ 1,069,253.41 $ 648,518 $ 701,388 $ 1,069,253 Power station - loss of income 1 1 1 Item $ 190,100.00 $ 190,100.00 $ 190,100.00 $ 190,100 $ 190,100 $ 190,100 Use of Mulwala canal 1 1 1 Item $ 350,000.00 $ 350,000.00 $ 350,000.00 $ 350,000 $ 350,000 $ 350,000

TOTAL RAW ANNUAL COST 1,188,618.21$ 1,241,488.41$ 1,609,353.41$

Contingency (%) 237,723.64$ 248,297.68$ 321,870.68$

TOTAL ANNUAL COST 1,426,341.85$ 1,489,786.09$ 1,931,224.09$


Cost AnalysisQuantity Price or Rates Cost Range

Quantity Price or Rates Cost Range

UNIT

UNIT

Cost Analysis


Option_7b_BA


BA Option 10a: Victorian Forest Channels (Kynmer Creek Route)




CAPITAL COSTS


EARTHWORKSTopsoil Stripping 135000 150000 195000 m3 $ 1.20 $ 1.20 $ 2.00 $ 162,000 $ 180,000 $ 390,000 Waterway Excavation 4203000 4670000 6071000 m3 $ 2.20 $ 2.20 $ 3.50 $ 9,246,600 $ 10,274,000 $ 21,248,500 Bank 234000 260000 338000 m3 $ 14.00 $ 16.00 $ 18.00 $ 3,276,000 $ 4,160,000 $ 6,084,000 Spoil bank - Place and trim 4104000 4560000 5928000 m3 $ 3.00 $ 3.00 $ 4.00 $ 12,312,000 $ 13,680,000 $ 23,712,000 Top soiling 63000 70000 91000 m3 $ 2.00 $ 2.00 $ 4.00 $ 126,000 $ 140,000 $ 364,000

STRUCTURESRegulators (including offtake and outfall) 5 5 7 No. $ 2,250,000.00 $ 2,500,000 $ 3,500,000.00 $ 11,250,000 $ 12,500,000 $ 24,500,000 Floodway Crossings (Beached spillways) 5 5 7 No. $ 270,000.00 $ 300,000 $ 420,000.00 $ 1,350,000 $ 1,500,000 $ 2,940,000 Irrigators Offtake 5 5 7 No. $ 27,000.00 $ 30,000 $ 42,000.00 $ 135,000 $ 150,000 $ 294,000 Road Crossings 5 5 7 No. $ 675,000.00 $ 750,000 $ 1,050,000.00 $ 3,375,000 $ 3,750,000 $ 7,350,000 Access Crossing 5 5 7 No. $ 360,000.00 $ 400,000 $ 560,000.00 $ 1,800,000 $ 2,000,000 $ 3,920,000

FENCTINGLongitudinal Fencing and gates 114000 114000 140000 m $ 7.20 $ 8.00 $ 10.40 $ 820,800 $ 912,000 $ 1,456,000 Temporary Fencing 1 1 1 Item $ 225,000.00 $ 250,000.00 $ 325,000.00 $ 225,000 $ 250,000 $ 325,000

Land AcquisitionTitle adjustments 50 50 70 No $ 2,250.00 $ 2,500.00 $ 3,250.00 $ 112,500 $ 125,000 $ 227,500 Land acquired as freehold 200 200 280 Ha $ 18,000.00 $ 20,000.00 $ 26,000.00 $ 3,600,000 $ 4,000,000 $ 7,280,000

Add rows as requiredTOTAL RAW CAPITAL COST 47,790,900$ 53,621,000$ 100,091,000$


Contingency (%) 22,939,632$ 25,738,080$ 48,043,680$


ANNUAL COSTS


Maintance Cost 0.5% of capital 1 1 1 Item $ 401,443.56 $ 450,416.40 $ 840,764.40 $ 401,444 $ 450,416 $ 840,764 Operational Cost no change to existing 1 1 1 Item $ 99,000.00 $ 100,000.00 $ 150,000.00 $ 99,000 $ 100,000 $ 150,000

TOTAL RAW ANNUAL COST 500,444$ 550,416$ 990,764$

Contingency (%) 100,089$ 110,083$ 198,153$

TOTAL ANNUAL COST 600,532$ 660,500$ 1,188,917$

Cost Analysis





Option_10a_BA


BA Option 10b: Victorian Forest Channels (Gulf Creek Route)




CAPITAL COSTS


EARTHWORKSTopsoil Stripping 90000 100000 130000 m3 $ 1.20 $ 1.20 $ 2.00 $ 108,000 $ 120,000 $ 260,000 Waterway Excavation 2655000 2950000 3835000 m3 $ 2.20 $ 2.20 $ 3.50 $ 5,841,000 $ 6,490,000 $ 13,422,500 Bank 153000 170000 221000 m3 $ 14.00 $ 16.00 $ 18.00 $ 2,142,000 $ 2,720,000 $ 3,978,000 Spoil bank - Place and trim 2592000 2880000 3744000 m3 $ 3.00 $ 3.00 $ 4.00 $ 7,776,000 $ 8,640,000 $ 14,976,000 Top soiling 45000 50000 65000 m3 $ 2.00 $ 2.00 $ 4.00 $ 90,000 $ 100,000 $ 260,000

STRUCTURESRegulators (including offtake and outfall) 3 3 4 No. $ 2,250,000.00 $ 2,500,000 $ 3,500,000.00 $ 6,750,000 $ 7,500,000 $ 14,000,000 Floodway Crossings (Beached spillways) 3 3 4 No. $ 270,000.00 $ 300,000 $ 420,000.00 $ 810,000 $ 900,000 $ 1,680,000 Irrigators Offtake 3 3 4 No. $ 27,000.00 $ 30,000 $ 42,000.00 $ 81,000 $ 90,000 $ 168,000 Road Crossings 3 3 4 No. $ 675,000.00 $ 750,000 $ 1,050,000.00 $ 2,025,000 $ 2,250,000 $ 4,200,000 Access Crossing 3 3 4 No. $ 360,000.00 $ 400,000 $ 560,000.00 $ 1,080,000 $ 1,200,000 $ 2,240,000

FENCTINGLongitudinal Fencing and gates 72000 72000 90000 m $ 7.20 $ 8.00 $ 10.40 $ 518,400 $ 576,000 $ 936,000 Temporary Fencing 1 1 1 Item $ 135,000.00 $ 150,000.00 $ 195,000.00 $ 135,000 $ 150,000 $ 195,000

Land AcquisitionTitle adjustments 30 30 30 No $ 2,250.00 $ 2,500.00 $ 3,250.00 $ 67,500 $ 75,000 $ 97,500

Land acquired as freehold 160 160 200 Ha $ 18,000.00 $ 20,000.00 $ 26,000.00 $ 2,880,000 $ 3,200,000 $ 5,200,000



Contingency (%) 14,545,872$ 16,325,280$ 29,574,240$


ANNUAL COSTS


Maintance Cost 0.5% of capital 1 1 1 Item $ 254,552.76 $ 285,692.40 $ 517,549.20 $ 254,553 $ 285,692 $ 517,549 Operational Cost no change to existing 1 1 1 Item $ 99,000.00 $ 100,000.00 $ 150,000.00 $ 99,000 $ 100,000 $ 150,000

TOTAL RAW ANNUAL COST 353,553$ 385,692$ 667,549$

Contingency (%) 70,711$ 77,138$ 133,510$


Cost Analysis





Option_10b_BA


BA Option 11: Increased diversion through the Wakool River




CAPITAL COSTS


Channel Excavation $ - $ - $ - Excavation 55800 62000 80600 m3 $ 4.50 $ 5.00 $ 6.50 $ 251,100 $ 310,000 $ 523,900

Inlet Works $ - $ - $ - Earthworks 1 1 1 Item $ 10,000.00 $ 12,000.00 $ 15,000.00 $ 10,000 $ 12,000 $ 15,000 Radial Gates 2 2 2 No. $ 50,000.00 $ 60,000.00 $ 75,000.00 $ 100,000 $ 120,000 $ 150,000

Structure 90 100 130 m3 $ 800.00 $ 900.00 $ 1,200.00 $ 72,000 $ 90,000 $ 156,000

Outlet Works $ - $ - $ - Earthworks 1 1 1 Item $ 10,800.00 $ 12,000.00 $ 15,600.00 $ 10,800 $ 12,000 $ 15,600 Structure 90 100 130 m3 $ 800.00 $ 900.00 $ 1,200.00 $ 72,000 $ 90,000 $ 156,000 Beaching 180 200 260 m3 $ 50.00 $ 60.00 $ 70.00 $ 9,000 $ 12,000 $ 18,200

Road Crossing $ - $ - $ - Bridge 270 270 300 m2 $ 1,400.00 $ 1,500.00 $ 1,600.00 $ 378,000 $ 405,000 $ 480,000 Earthworks 1 1 1 Item $ 90,000.00 $ 100,000.00 $ 120,000.00 $ 90,000 $ 100,000 $ 120,000

TOTAL RAW CAPITAL COST 992,900$ 1,151,000$ 1,634,700$


Contingency (%) 476,592$ 552,480$ 784,656$


ANNUAL COSTS


Use of Mulwala canal 1 1 1 Item $ 350,000.00 $ 350,000.00 $ 350,000.00 $ 350,000 $ 350,000 $ 350,000 TOTAL RAW ANNUAL COST 350,000.00$ 350,000.00$ 350,000.00$

Contingency (%) 70,000.00$ 70,000.00$ 70,000.00$

TOTAL ANNUAL COST 420,000.00$ 420,000.00$ 420,000.00$

Cost Analysis





Option_11_BA


BA Option 12: Increased escape capacity to the Edward River




CAPITAL COSTS


Remove Existing Structure $ - $ - $ - Site Establishment 1 1 1 Item $ 10,000.00 $ 12,000.00 $ 15,000.00 $ 10,000 $ 12,000 $ 15,000 Remove existing structure 126 140 180 m3 $ 150.00 $ 150.00 $ 180.00 $ 18,900 $ 21,000 $ 32,400 Cartage 1 1 1 Item $ 5,000.00 $ 5,000.00 $ 7,000.00 $ 5,000 $ 5,000 $ 7,000

Channel Excavation $ - $ - $ - Excavation 8100 9000 11700 m3 $ 4.50 $ 5.00 $ 6.50 $ 36,450 $ 45,000 $ 76,050 Concrete Lining 1035 1150 1495 m3 $ 550.00 $ 650.00 $ 845.00 $ 569,250 $ 747,500 $ 1,263,275

Inlet Works $ - $ - $ - Earthworks 1 1 1 Item $ 10,000.00 $ 12,000.00 $ 15,000.00 $ 10,000 $ 12,000 $ 15,000 Radial Gates 2 2 2 No. $ 76,000.00 $ 85,000.00 $ 100,000.00 $ 152,000 $ 170,000 $ 200,000 Structure 90 100 130 m3 $ 800.00 $ 900.00 $ 1,200.00 $ 72,000 $ 90,000 $ 156,000

Outlet Works $ - $ - $ - Earthworks 1 1 1 Item $ 10,000.00 $ 12,000.00 $ 15,000.00 $ 10,000 $ 12,000 $ 15,000 Structure 90 100 130 m3 $ 800.00 $ 900.00 $ 1,200.00 $ 72,000 $ 90,000 $ 156,000 Beaching 90 100 130 m3 $ 50.00 $ 60.00 $ 70.00 $ 4,500 $ 6,000 $ 9,100

Pericoota Channel Works $ - $ - $ - Earthworks 1 1 1 Item $ 180,000.00 $ 200,000.00 $ 260,000.00 $ 180,000 $ 200,000 $ 260,000 Structure 1 1 1 Item $ 54,000.00 $ 60,000.00 $ 78,000.00 $ 54,000 $ 60,000 $ 78,000 Beaching 1 1 1 Item $ 45,000.00 $ 50,000.00 $ 65,000.00 $ 45,000 $ 50,000 $ 65,000



Contingency (%) 594,768$ 729,840$ 1,126,956$


ANNUAL COSTS


Use of Mulwala canal 1 1 1 Item $ 350,000.00 $ 350,000.00 $ 350,000.00 $ 350,000 $ 350,000 $ 350,000 TOTAL RAW ANNUAL COST 350,000.00$ 350,000.00$ 350,000.00$

Contingency (%) 70,000.00$ 70,000.00$ 70,000.00$

TOTAL ANNUAL COST 420,000.00$ 420,000.00$ 420,000.00$

Cost Analysis





Option_12_BA


BA Option 13: Increased escape capacity to Broken Creek




CAPITAL COSTS


EARTHWORKS $ - $ - $ - Yarrawonga Main Canal $ - $ - $ -

Stripping 24300 27000 35100 m3 $ 1.20 $ 1.20 $ 2.00 $ 29,160 $ 32,400 $ 70,200

Waterway Excavation 113400 126000 163800 m3 $ 2.20 $ 2.20 $ 3.50 $ 249,480 $ 277,200 $ 573,300

Bank - Compacted 105300 117000 152100 m3 $ 14.00 $ 16.00 $ 18.00 $ 1,474,200 $ 1,872,000 $ 2,737,800

Bank - Uncompacted (Topsoil) 17496 19440 25272 m3 $ 3.00 $ 3.00 $ 4.00 $ 52,488 $ 58,320 $ 101,088

Spoil bank - Place, compact and trim 9450 10500 13650 m3 $ 3.00 $ 3.00 $ 4.00 $ 28,350 $ 31,500 $ 54,600

Excavation for clay lining (600 mm) 54000 60000 78000 m3 $ 2.20 $ 2.20 $ 3.50 $ 118,800 $ 132,000 $ 273,000

450 mm clay lining 52650 58500 76050 m3 $ 14.00 $ 16.00 $ 18.00 $ 737,100 $ 936,000 $ 1,368,900

150 mm crush rock lining 13500 15000 19500 m3 $ 50.00 $ 60.00 $ 70.00 $ 675,000 $ 900,000 $ 1,365,000 Murray Valley Channel No 3 (0-4800m) $ - $ - $ - Stripping 12960 14400 18720 m3 $ 1.20 $ 1.20 $ 2.00 $ 15,552 $ 17,280 $ 37,440

Waterway Excavation 33300 37000 48100 m3 $ 2.20 $ 2.20 $ 3.50 $ 73,260 $ 81,400 $ 168,350

Bank - Compacted 33696 37440 48672 m3 $ 14.00 $ 16.00 $ 18.00 $ 471,744 $ 599,040 $ 876,096

Bank - Uncompacted (Topsoil) 4665.6 5184 6739.2 m3 $ 3.00 $ 3.00 $ 4.00 $ 13,997 $ 15,552 $ 26,957

Spoil bank - Place, compact and trim 9 10 13 m3 $ 3.00 $ 3.00 $ 4.00 $ 27 $ 30 $ 52 Excavation for clay lining (600 mm) 16200 18000 23400 m3 $ 2.20 $ 2.20 $ 3.50 $ 35,640 $ 39,600 $ 81,900

450 mm clay lining 15795 17550 22815 m3 $ 14.00 $ 16.00 $ 18.00 $ 221,130 $ 280,800 $ 410,670

150 mm crush rock lining 4050 4500 5850 m3 $ 50.00 $ 60.00 $ 70.00 $ 202,500 $ 270,000 $ 409,500 Connector - Channel 3 to Boosey Creek

(3200m)Stripping 8640 9600 12480 m3 $ 1.20 $ 1.20 $ 2.00 $ 10,368 $ 11,520 $ 24,960 Waterway Excavation 63360 70400 91520 m3 $ 2.20 $ 2.20 $ 3.50 $ 139,392 $ 154,880 $ 320,320

Bank - Compacted 18720 20800 27040 m3 $ 14.00 $ 16.00 $ 18.00 $ 262,080 $ 332,800 $ 486,720

Bank - Uncompacted (Topsoil) 3110.4 3456 4492.8 m3 $ 3.00 $ 3.00 $ 4.00 $ 9,331 $ 10,368 $ 17,971

Spoil bank - Place, compact and trim 44640 49600 64480 m3 $ 3.00 $ 3.00 $ 4.00 $ 133,920 $ 148,800 $ 257,920 BRIDGES $ - $ - $ -

MV Channel No. 3 - Occupation 3 3 4 No. $ 108,000.00 $ 120,000.00 $ 156,000.00 $ 324,000 $ 360,000 $ 624,000

MV Channel No. 3 - Road 2 2 3 No. $ 225,000.00 $ 250,000.00 $ 325,000.00 $ 450,000 $ 500,000 $ 975,000

Connector - Occupation 2 2 3 No. $ 90,000.00 $ 100,000.00 $ 130,000.00 $ 180,000 $ 200,000 $ 390,000

Connector - Road 1 1 1 No. $ 180,000.00 $ 200,000.00 $ 260,000.00 $ 180,000 $ 200,000 $ 260,000 SUBWAYS $ - $ - $ -

MV Channel No. 3 3 3 4 No. $ 45,000.00 $ 50,000.00 $ 65,000.00 $ 135,000 $ 150,000 $ 260,000

Connector 2 2 3 No. $ 36,000.00 $ 40,000.00 $ 52,000.00 $ 72,000 $ 80,000 $ 156,000 SIPHONS $ - $ - $ -

MV Channel No. 3 1 1 1 No. $ 450,000.00 $ 500,000.00 $ 650,000.00 $ 450,000 $ 500,000 $ 650,000

REGULATORS $ - $ - $ -

YMC - 8 Mile Weir 1 1 1 No. $ 225,000.00 $ 250,000.00 $ 325,000.00 $ 225,000 $ 250,000 $ 325,000

MV Channel No. 3 2 2 3 No. $ 135,000.00 $ 150,000.00 $ 195,000.00 $ 270,000 $ 300,000 $ 585,000 Connector 1 1 1 No. $ 67,500.00 $ 75,000.00 $ 97,500.00 $ 67,500 $ 75,000 $ 97,500

ON-FARM WORKS $ - $ - $ -

YMC 1 1 1 Item $ 45,000.00 $ 50,000.00 $ 65,000.00 $ 45,000 $ 50,000 $ 65,000

MV Channel No. 3 1 1 1 Item $ 45,000.00 $ 50,000.00 $ 65,000.00 $ 45,000 $ 50,000 $ 65,000

Connector 1 1 1 Item $ 27,000.00 $ 30,000.00 $ 39,000.00 $ 27,000 $ 30,000 $ 39,000 FENCTING $ - $ - $ -

YMC 18000 18000 23400 m $ 7.20 $ 8.00 $ 10.40 $ 129,600 $ 144,000 $ 243,360

MV Channel No. 3 4800 4800 6240 m $ 7.20 $ 8.00 $ 10.40 $ 34,560 $ 38,400 $ 64,896

Connector 6400 6400 8320 m $ 7.20 $ 8.00 $ 10.40 $ 46,080 $ 51,200 $ 86,528 Land Acquisition $ - $ - $ -

Title adjustments 25 25 33 No $ 2,250.00 $ 2,500.00 $ 3,250.00 $ 56,250 $ 62,500 $ 107,250

Land acquired as freehold 30 30 40 Ha $ 18,000.00 $ 20,000.00 $ 26,000.00 $ 540,000 $ 600,000 $ 1,040,000 $ - $ - $ -



Contingency (%) 3,950,644$ 4,724,443$ 7,534,213$


ANNUAL COSTS


Maintance Cost 1% of capital 1 1 1 Item $ 78,471.29 $ 93,021.60 $ 147,760.27 $ 78,471 $ 93,022 $ 147,760 Power station - loss of income 1 1 1 Item $ 190,100.00 $ 190,100.00 $ 190,100.00 $ 190,100 $ 190,100 $ 190,100


Contingency (%) 53,714$ 56,624$ 67,572$


Cost Analysis





Option_13_BA


BA Option 15: Murray Goulburn interconnector (2000ML/d)




CAPITAL COSTS


EARTHWORKS $ - $ - $ - Connector Channel to EGMC $ - $ - $ - Stripping 477000 530000 689000 m3 $ 1.20 $ 1.20 $ 2.00 $ 572,400 $ 636,000 $ 1,378,000 Waterway Excavation 4590000 5100000 6630000 m3 $ 2.20 $ 2.20 $ 3.50 $ 10,098,000 $ 11,220,000 $ 23,205,000 Bank - Compacted 4050000 4500000 5850000 m3 $ 14.00 $ 16.00 $ 18.00 $ 56,700,000 $ 72,000,000 $ 105,300,000 Bank - Uncompacted (Topsoil) 144000 160000 208000 m3 $ 3.00 $ 3.00 $ 4.00 $ 432,000 $ 480,000 $ 832,000 Spoil bank - Place, compact and trim 639000 710000 923000 m3 $ 3.00 $ 3.00 $ 4.00 $ 1,917,000 $ 2,130,000 $ 3,692,000 Excavation for clay lining (600 mm) 301000 430000 602000 m3 $ 2.20 $ 2.20 $ 3.50 $ 662,200 $ 946,000 $ 2,107,000 450 mm clay lining 224000 320000 448000 m3 $ 14.00 $ 16.00 $ 18.00 $ 3,136,000 $ 5,120,000 $ 8,064,000 150 mm crush rock lining 77000 110000 154000 m3 $ 50.00 $ 60.00 $ 70.00 $ 3,850,000 $ 6,600,000 $ 10,780,000 Beaching protection 105000 150000 210000 m3 $ 50.00 $ 60.00 $ 70.00 $ 5,250,000 $ 9,000,000 $ 14,700,000

BRIDGES $ - $ - $ - Connector - Highway 1 1 2 No. $ 828,000.00 $ 920,000.00 $ 1,196,000.00 $ 828,000 $ 920,000 $ 2,392,000 Connector - Major Road 5 6 9 No. $ 621,000.00 $ 690,000.00 $ 897,000.00 $ 3,105,000 $ 4,140,000 $ 8,073,000 Connector - Minor Road 32 36 45 No. $ 450,000.00 $ 500,000.00 $ 650,000.00 $ 14,400,000 $ 18,000,000 $ 29,250,000 Connector - Occupation 100 110 150 No. $ 288,000.00 $ 320,000.00 $ 416,000.00 $ 28,800,000 $ 35,200,000 $ 62,400,000

SUBWAYS $ - $ - $ - Connector 18 20 30 No. $ 225,000.00 $ 250,000.00 $ 325,000.00 $ 4,050,000 $ 5,000,000 $ 9,750,000

SIPHONS $ - $ - $ - Connector 6 7 10 No. $ 2,250,000.00 $ 2,500,000.00 $ 3,250,000.00 $ 13,500,000 $ 17,500,000 $ 32,500,000

Offtake Works (Lake Mulwala/YMC) $ - $ - $ - Offtake 1 1 1 Item $ 5,760,000.00 $ 6,400,000.00 $ 8,320,000.00 $ 5,760,000 $ 6,400,000 $ 8,320,000

Regulators $ - $ - $ - Connector 3 3 5 No. $ 2,250,000.00 $ 2,500,000.00 $ 3,250,000.00 $ 6,750,000 $ 7,500,000 $ 16,250,000

ON-FARM WORKS $ - $ - $ - Connector 1 1 1 Item $ 4,500,000.00 $ 5,000,000.00 $ 6,500,000.00 $ 4,500,000 $ 5,000,000 $ 6,500,000

FENCTING $ - $ - $ - Connector 129600 144000 172800 m $ 7.20 $ 8.00 $ 10.00 $ 933,120 $ 1,152,000 $ 1,728,000

Land Acquisition $ - $ - $ - Title adjustments 99 110 132 No $ 9,000.00 $ 10,000.00 $ 13,000.00 $ 891,000 $ 1,100,000 $ 1,716,000 Land acquired as freehold 468 520 624 Ha $ 18,000.00 $ 20,000.00 $ 26,000.00 $ 8,424,000 $ 10,400,000 $ 16,224,000



Contingency (%) 83,788,186$ 105,813,120$ 175,277,280$


ANNUAL COSTS


Maintance Cost 0.3-0.5% of capital 1 1 1 Item $ 1,188,698.11 $ 1,488,406.08 $ 2,495,957.52 $ 1,188,698 $ 1,488,406 $ 2,495,958 Operational Cost one operator and vehicle 1 1 1 Item $ 250,000.00 $ 250,000.00 $ 250,000.00 $ 250,000 $ 250,000 $ 250,000

$ - $ - $ - TOTAL RAW ANNUAL COST 1,438,698$ 1,738,406$ 2,745,958$

Contingency (%) 287,740$ 347,681$ 549,192$

TOTAL ANNUAL COST 1,726,438$ 2,086,087$ 3,295,149$

Cost Analysis





Option_15_BA


Barmah Choke Study - MDBA

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