River modelling for Northern Australia · The authors gratefully acknowledge the assistance provided by the Western Australian, Northern Territory and Queensland governments throughout

River modelling for Northern AustraliaCuan Petheram, Donna Hughes, Paul Rustomji, Kathryn Smith, Tom G Van Niel and Ang Yang

December 2009A report to the Australian Government from the CSIRO Northern Australia Sustainable Yields Project

Northern Australia Sustainable Yields Project acknowledgments Prepared by CSIRO for the Australian Government under the Raising National Water Standards Program of the National Water Commission (NWC). Important aspects of the work were undertaken by the Northern Territory Department of Natural Resources, Environment, The Arts and Sport (NRETAS); the Queensland Department of Environment and Resource Management (QDERM); the New South Wales Department of Water and Energy; Sinclair Knight Merz; Environmental Hydrology Associates and Jolly Consulting.

The Project was guided and reviewed by a Steering Committee (Kerry Olsson, NWC – co-chair; Chris Schweizer, Department of the Environment, Water, Heritage and the Arts (DEWHA) – co-chair; Tom Hatton, CSIRO; Louise Minty, Bureau of Meteorology (BoM); Lucy, Vincent, Bureau of Rural Sciences (BRS); Tom Crothers, QDERM; Lyall Hinrichsen, QDERM; Ian Lancaster, NRETAS; Mark Pearcey, DoW; Michael Douglas, Tropical Rivers and Coastal Knowledge (TRaCK); Dene Moliere, Environmental Research Institute of the Supervising Scientist (eriss); secretariat support by Angus MacGregor, DEWHA) and benefited from additional reviews by a Technical Reference Panel and other experts, both inside and outside CSIRO.

Northern Australia Sustainable Yields Project disclaimers

Derived from or contains data and/or software provided by the Organisations. The Organisations give no warranty in relation to the data and/or software they provided (including accuracy, reliability, completeness, currency or suitability) and accept no liability (including without limitation, liability in negligence) for any loss, damage or costs (including consequential damage) relating to any use or reliance on the data or software including any material derived from that data or software. Data must not be used for direct marketing or be used in breach of the privacy laws. Organisations include: the Northern Territory Department of Natural Resources, Environment, The Arts and Sport; the Queensland Department of Environment and Resource Management; the New South Wales Department of Water and Energy.

CSIRO advises that the information contained in this publication comprises general statements based on scientific research. The reader is advised and needs to be aware that such information may be incomplete or unable to be used in any specific situation. No reliance or actions must therefore be made on that information without seeking prior expert professional, scientific and technical advice. To the extent permitted by law, CSIRO (including its employees and consultants) excludes all liability to any person for any consequences, including but not limited to all losses, damages, costs, expenses and any other compensation, arising directly or indirectly from using this publication (in part or in whole) and any information or material contained in it. Data are assumed to be correct as received from the organisations.

Citation

Petheram C, Hughes D, Rustomji P, Smith K, Van Neil TG and Yang A (2009) Information supporting river modelling undertaken for the Northern Australia Sustainable Yields project. A report to the Australian Government from the CSIRO Northern Australia Sustainable Yields Project. CSIRO Water for a Healthy Country Flagship, Australia

Publication Details

Published by CSIRO © 2009 all rights reserved. This work is copyright. Apart from any use as permitted under the Copyright Act 1968, no part may be reproduced by any process without prior written permission from CSIRO.

ISSN 1835-095X

Cover photograph: Diversion Dam on the Ord River, WA. 1971. Photographer: Richard Harrison

© CSIRO 2009 River modelling for northern Australia ▪ iii

Acknowledgments

The authors gratefully acknowledge the assistance provided by the Western Australian, Northern Territory and

Queensland governments throughout the project. The Western Australian Department of Water provided in-kind support

to run their MIKE BASIN model for the lower Ord River and the Northern Territory Department of Natural Resources,

Environment, the Arts and Sport provided in-kind support to run their FEFLOW-Mike 11 model for the Daly River

catchment. The Queensland Department of Environment and Resource Management extended and made their

Integrated Quantity and Quality Models for the Leichhardt, Flinders, Gilbert and Mitchell rivers available to the Northern

Australia Sustainable Yields Project team. Staff from the three jurisdictions are thanked for reviewing the river system

modelling results.

The authors would also like to thank Sinclair Knight Merz for running their model of the Darwin River Dam for the

Northern Australia Sustainable Yields Project and for their contribution to the river system modelling section in the Van

Diemen region chapter of the Timor Sea Division report.

The authors would like to thank Geoff Podger for his help and advice and Dr David Post for reviewing this manuscript.

They would also like to acknowledge the helpful comments provided by the Northern Australia Sustainable Yields Project

steering committee and technical review panel throughout the project.

Finally the authors would like to acknowledge the tireless efforts of the Northern Australia Sustainable Yields reporting

team in bringing this document to fruition. Specifically Frances Marston, Simon Gallant, Ben Wurcker and Alex Dyce.

Susan Cuddy and Becky Schmidt are thanked for their work on the drainage division reports, some material of which

appears in this report.

iv ▪ River modelling for northern Australia © CSIRO 2009

Acronyms

AHD Australian Height Datum

APET Actual Potential Evapotranspiration

AWRC Australian Water Resources Council

DERM Queensland Department of Environment and Resource Management

DoW Department of Water (Western Australia)

EWP Environmental Water Provisions

FDC Flow Duration Curve

GCM Global Climate Model

IDL Interactive Data Language

IQQM Integrated Quantity and Quality Model

LUCICAT Land Use Change Incorporated CATchment

NALWT Northern Australia Land and Water Taskforce

NASY Northern Australia Sustainable Yields Project

NAWFA Northern Australia Water Futures Assessment

NLWRA National Land and Water Resources Audit

NSE Nash-Sutcliffe Efficiency

NRETAS Northern Territory Department of Natural Resources, Environment, the Arts and Sport

ORD Ord River Dam

SRN Streamflow Reporting Node

© CSIRO 2009 River modelling for northern Australia ▪ v

Preface

This is a report to the Australian Government from CSIRO. It is an output of the CSIRO Northern Australia Sustainable

Yields Project which, together with allied projects for Tasmania and south-west Western Australia, will provide a nation-

wide expansion of the assessments that began with the CSIRO Murray-Darling Basin Sustainable Yields Project.

The projects are the first rigorous attempt to estimate the impacts of catchment development, changing groundwater

extraction, climate variability and anticipated climate change on water resources at a whole-of-region scale, explicitly

considering the connectivity of surface and groundwater systems. The CSIRO Northern Australia Sustainable Yields

Project has undertaken the most comprehensive hydrological modelling ever attempted for the region, using rainfall-

runoff models, groundwater recharge models, river system models and groundwater models, and considering all

upstream-downstream and surface-subsurface connections.

vi ▪ River modelling for northern Australia © CSIRO 2009

Executive summary

The Northern Australia Sustainable Yields Project marks the first time a consistent, robust and transparent assessment

has been carried out across the three jurisdictions of northern Australia, and the first time models have included an

assessment of possible future climate implications. Four scenarios were assessed as part of the project:

• historical climate (1930 to 2007) and current development (Scenario A)

• recent climate (1996 to 2007) and current development (Scenario B)

• future climate (~2030) and current development (Scenario C)

• future climate (~2030) and likely future development (Scenario D).

The results are contained within three drainage division reports (i.e. Northern North-East Coast Drainage Division, Gulf of

Carpentaria Drainage Division and the Timor Sea Drainage Division). Accompanying these drainage division reports are

a series of CSIRO Water for a Healthy Country Flagship Science Reports, which contain supporting technical material.

This report provides technical material in support of the river system modelling results presented in Section 3.6 of the

regional chapters of the drainage division reports.

River system models encapsulate descriptions of current infrastructure, water demands and water management and

sharing rules and can be used to assess the implications of the changes in inflows described in the rainfall-runoff section

on the reliability of water supply to users. They may also be used to support water management planning by assessing

the trade-offs between supplies to various competing categories of users. Given the time constraints of the project and

the need to link the assessments to jurisdiction water planning processes, it was necessary to use the river system

models currently used by these agencies. Where information on infrastructure, water demand, water management and

sharing rules or future development were not provided, a river modelling section was not warranted.

Six river system models were used in this project; a MIKE BASIN model for the lower Ord River catchment, a simple

single node reservoir model for the Darwin River Dam, and Integrated Quantity and Quality Models for the Leichhardt,

Flinders, Gilbert and Mitchell river catchments. In addition to the river system models a coupled groundwater-hydraulic

model (technically not a river system model) was used for the Daly river catchment. The description and setup of the

Daly model is detailed in an accompanying report. For the river system models and the Daly river model a variety of

metrics are reported, including water availability, level of consumptive use and storage behaviour of spills. A collective

summary of the key results is provided in this report. Detailed results are contained within the drainage division reports.

All the rivers examined in this report are gaining rivers, that is their mean annual flow increases towards the coast and is

highest at the end-of-system. It should be noted, however, that not all of the water at the most downstream gauge is

accessible for consumptive use. This is because there are few intermediate and large potential reservoir locations. The

Gulf of Carpentaria in particular is mostly flat and has broad coastal plains so there are few potential reservoir locations

in the lower reaches of this division. Ungauged inflows constitute the majority of flow in all catchments. In the Leichhardt,

Gilbert and Mitchell, large ungauged flows occur downstream of the last gauge. In all catchments, the mean annual flow

under Scenario CNmid is similar to Scenario AN. In the Gilbert and Flinders rivers, mean annual flows along the transect

are less under Scenario BN than under Scenario AN. In the Ord and Daly rivers, however, mean annual flow is

considerably higher under Scenario BN than under Scenario AN or Scenario CNwet. Hence, extreme caution should be

exercised if future management decisions are to be based on hydrological data from the recent climate only.

The Integrated Quantity and Quality Models (i.e. for the Leichhardt, Flinders, Gilbert and Mitchell) in the Gulf of

Carpentaria were developed assuming the full use of existing entitlements. A consequence of this is that these models

do not simulate current levels of development. Nevertheless water usage within the Gulf of Carpentaria river systems is

low (typically less than several percent of the total inflows) relative to river systems in the Murray Darling Basin. It should

be noted, however, that in the river systems of the Gulf of Carpentaria, the level of use tends to be highest in the upper

reaches of the catchments, which is also where the water availability is lowest. Nevertheless, with the exception of the

Leichhardt, the level of use does not exceed 10 percent at any point within these systems. In the Liechhardt, which

supplies water to the mining town of Mount Isa and surrounding mines, the level of use exceeds 25 percent under

Scenario A. In the Timor Sea Drainage Division, the level of use in the Ord River (including water used for

hydroelectricity generation) and Darwin River are relatively high, 57 and 36 percent respectively. The degree of

© CSIRO 2009 River modelling for northern Australia ▪ vii

regulation of the Ord River Dam (0.8) and Darwin River Dam (0.64) are high relative to storages in the other river

modelling systems.

All rivers exhibit a strong seasonality of flow at the end-of-system gauges reflecting the wet and dry seasons. With the

exception of the Ord, there are minimal changes in end-of-system flows compared to without-development conditions

under all scenarios. It is possible, however, that changes to the river flow regime due to development or climate change

may be important locally. Under climate scenarios there is not a large impact to low flows at the end-of-system. In the

Ord, however, wet season flows have been moderated considerably due to the Ord River Dam. Conversely dry season

flows have increased substantially. Where once the system was ephemeral it is now perennial.

In those regions where information on infrastructure, water demand, water management and sharing rules or future

development were not provided no river modelling assessment was undertaken. The development of river system

models for these regions is not warranted unless future development occurs.

viii ▪ River modelling for northern Australia © CSIRO 2009

Table of Contents

Acknowledgments.................................................................................................................................................................... iii Acronyms................................................................................................................................................................................. iv Preface v

Executive summary..................................................................................................................................vi

1 Introduction............................................................................................................................... 1

2 Project area .............................................................................................................................. 4 2.1 General setting.............................................................................................................................................................4 2.2 Climate.........................................................................................................................................................................6

2.2.1 River flow characteristics................................................................................................................................8

3 Methods..................................................................................................................................... 9 3.1 General approach.........................................................................................................................................................9

3.1.1 Preparation of climate data...........................................................................................................................10 3.1.2 Digital elevation model and flow direction grids ............................................................................................10 3.1.3 Rainfall-runoff modelling...............................................................................................................................10 3.1.4 River system modelling ................................................................................................................................11

3.2 River model specific information.................................................................................................................................15 3.2.1 Ord...............................................................................................................................................................15

3.3 Darwin river reservoir .................................................................................................................................................25 3.4 Leichhardt ..................................................................................................................................................................30 3.5 Flinders ......................................................................................................................................................................45 3.6 Gilbert ........................................................................................................................................................................64 3.7 Mitchell.......................................................................................................................................................................81

4 Summary ............................................................................................................................... 100

5 References ............................................................................................................................ 106

Appendix 1............................................................................................................................................ 108

Tables

Table 1. Major storage in the Ord river system model ....................................................................................................................19 Table 2. Modelled water use configuration in the Ord system ........................................................................................................19 Table 3. Ord river system model setup information ........................................................................................................................19 Table 4. Ord river system model mean annual water balance under Scenario A and under scenarios B, C and D relative to

Scenario A...............................................................................................................................................................................24 Table 5. Summary table for Ord system.........................................................................................................................................24 Table 6. Storages in the Darwin River Dam system model.............................................................................................................26 Table 7. Modelled water use configuration in the Darwin River Dam system model .......................................................................26 Table 8. Darwin River Dam system model setup information .........................................................................................................27 Table 9. River system model mean annual water balance under Scenario A and under scenarios B, C and D relative to Scenario A

................................................................................................................................................................................................27 Table 10. Darwin River Dam – Streamflow scaling factors for Scenario B......................................................................................28 Table 11. Darwin River Dam – Rainfall Scaling factors for Scenario B ...........................................................................................28 Table 12. Darwin River Dam – Evaporation scaling factors for Scenario B.....................................................................................28 Table 13. Darwin River Dam – Streamflow scaling factors for Scenario Cwet ................................................................................28 Table 14. Darwin River Dam – Streamflow scaling factors for Scenario Cmid................................................................................28 Table 15. Darwin River Dam – Streamflow Scaling factors for Scenario Cdry ................................................................................28 Table 16. Darwin River Dam – Rainfall scaling factors for Scenario Cwet ......................................................................................28 Table 17. Darwin River Dam – Rainfall scaling factors for Scenario Cmid......................................................................................28 Table 18. Darwin River Dam – Rainfall scaling factors for Scenario Cdry.......................................................................................28 Table 19. Darwin River Dam – Evaporation scaling factors for Scenario Cwet ...............................................................................29 Table 20. Darwin River Dam – Evaporation scaling factors for Scenario Cmid...............................................................................29 Table 21. Darwin River Dam – Evaporation scaling factors for Scenario Cdry................................................................................29 Table 22. Major storages in the Leichhardt river system model......................................................................................................32 Table 23. Modelled water use configuration in the Leichhardt river system model..........................................................................33

© CSIRO 2009 River modelling for northern Australia ▪ ix

Table 24. Leichhardt river system model setup information............................................................................................................33 Table 25. Leichhardt river system model mean annual water balance under Scenario A and under scenarios B and C relative to

Scenario A...............................................................................................................................................................................35 Table 26. Leichardt water balance – gauge 913999.......................................................................................................................36 Table 27. Leichardt River water balance – gauge 913003..............................................................................................................37 Table 28. Leichardt River water balance – gauge 913007..............................................................................................................37 Table 29. Leichardt River water balance – gauge 913004..............................................................................................................38 Table 30. Leichardt River water balance – gauge 913012..............................................................................................................38 Table 31. Leichardt River water balance – gauge 913014..............................................................................................................39 Table 32. Leichardt River – Streamflow scaling factors forScenario B............................................................................................41 Table 33. Leichardt River – Rainfall scaling factors for Scenario B.................................................................................................41 Table 34. Leichardt River – Evaporation scaling factors for Scenario B..........................................................................................41 Table 35. Leichardt River – Streamflow scaling factors for Scenario Cwet .....................................................................................42 Table 36. Leichardt River – Streamflow scaling factors for Scenario Cmid.....................................................................................42 Table 37. Leichardt River – Streamflow scaling factors for Scenario Cdry......................................................................................43 Table 38. Leichardt River – Rainfall scaling factors for Scenario Cwet ...........................................................................................43 Table 39. Leichardt River – Rainfall scaling factors for Scenario Cmid...........................................................................................43 Table 40. Leichardt River – Rainfall scaling factors for Scenario Cdry ...........................................................................................43 Table 41. Leichardt River – Evaporation scaling factors for Scenario Cwet ....................................................................................43 Table 42. Leichardt River – Evaporation scaling factors for Scenario Cmid....................................................................................44 Table 43. Leichardt River – Evaporation scaling factors for Scenario Cdry ....................................................................................44 Table 44. Storages in the Flinders river system model ...................................................................................................................47 Table 45. Modelled water use configuration in the Flinders river system model .............................................................................48 Table 46. Flinders river system model setup information................................................................................................................48 Table 47. Finders river system model mean annual water balance under Scenario A and under scenarios B and C relative to

Scenario A...............................................................................................................................................................................49 Table 48. Flinders River water balance – gauge 915999................................................................................................................50 Table 49. Flinders River water balance – gauge 915003................................................................................................................50 Table 50. Flinders River water balance – gauge 915209................................................................................................................51 Table 51. Flinders River water balance – gauge 915212................................................................................................................51 Table 52. Flinders River water balance – gauge 915203................................................................................................................52 Table 53. Flinders River water balance – gauge 915204................................................................................................................52 Table 54. Flinders River water balance – gauge 915014................................................................................................................53 Table 55. Flinders River water balance – gauge 915012................................................................................................................53 Table 56. Flinders River water balance – gauge 915008................................................................................................................54 Table 57. Flinders River water balance – gauge 915004................................................................................................................54 Table 58. Flinders River – Streamflow scaling factors for Scenario B.............................................................................................56 Table 59. Flinders River – Rainfall scaling factors for Scenario B r ................................................................................................57 Table 60. Flinders River – Evaporation scaling factors for Scenario B............................................................................................57 Table 61. Flinders River – Streamflow scaling factors for Scenario Cwet .......................................................................................58 Table 62. Flinders River – Streamflow scaling factors for Scenario Cmid.......................................................................................59 Table 63. Flinders River – Streamflow scaling factors for Scenario Cdry........................................................................................60 Table 64. Flinders River – Rainfall scaling factors for Scenario Cwet.............................................................................................61 Table 65 Flinders River – Rainfall scaling factors for Scenario Cmid..............................................................................................61 Table 66. Flinders River – Rainfall scaling factors for Scenario Cdry .............................................................................................62 Table 67. Flinders River – Evaporation scaling factors for Scenario Cwet ......................................................................................62 Table 68. Flinders River – Evaporation scaling factors for Scenario Cmid......................................................................................63 Table 69. Flinders River – Evaporation scaling factors for Scenario Cdry ......................................................................................63 Table 70. Storages in the Gilbert system river model .....................................................................................................................66 Table 71. Modelled water use configuration in the Gilbert system river model................................................................................67 Table 72. Gilbert system river model setup information..................................................................................................................67 Table 73. Gilbert system river model mean annual water balance under Scenario A and under scenarios B and C relative to

Scenario A...............................................................................................................................................................................68 Table 74. Gilbert River water balance – gauge 917999..................................................................................................................69 Table 75. Gilbert River water balance – gauge 917009..................................................................................................................69 Table 76. Gilbert River water balance – gauge 917111..................................................................................................................70 Table 77. Gilbert River water balance – gauge 917113..................................................................................................................70 Table 78. Gilbert River water balance – gauge 917112..................................................................................................................71 Table 79. Gilbert River water balance – gauge 917109..................................................................................................................71 Table 80. Gilbert River water balance – gauge 917106..................................................................................................................72

x ▪ River modelling for northern Australia © CSIRO 2009

Table 81. Gilbert River water balance – gauge 917102..................................................................................................................72 Table 82. Gilbert River water balance – gauge 917108..................................................................................................................73 Table 83. Gilbert River water balance – gauge 917001..................................................................................................................73 Table 84. Gilbert River water balance – gauge 917013..................................................................................................................74 Table 85. Gilbert River water balance – gauge 917013..................................................................................................................74 Table 86. Gilbert River – Streamflow scaling factors for Scenario B...............................................................................................76 Table 87. Gilbert River – Rainfall scaling factors for Scenario B.....................................................................................................76 Table 88. Gilbert River – Evaporation scaling factors for Scenario B..............................................................................................76 Table 89. Gilbert River – Streamflow scaling factors for Scenario Cwet .........................................................................................77 Table 90. Gilbert River – Streamflow scaling factors for Scenario Cmid.........................................................................................78 Table 91. Gilbert River – Streamflow scaling factors for Scenario Cdry..........................................................................................79 Table 92. Gilbert River – Rainfall scaling factors for Scenario Cwet ...............................................................................................79 Table 93. Gilbert River – Rainfall scaling factors for Scenario Cmid...............................................................................................80 Table 94. Gilbert River – Rainfall scaling factors for Scenario Cdry................................................................................................80 Table 95. Gilbert River – Evaporation scaling factors for Scenario Cwet ........................................................................................80 Table 96. Gilbert River – Evaporation scaling factors for Scenario Cmid........................................................................................80 Table 97. Gilbert River – Evaporation scaling factors for Scenario Cdry.........................................................................................80 Table 98. Storages in the river system model ................................................................................................................................82 Table 99. Modelled water use configuration...................................................................................................................................83 Table 100. Mitchell system river model setup information ..............................................................................................................84 Table 101. Mitchell system river model average annual water balance under scenarios A, B and C ..............................................85 Table 102. Mitchell River water balance – gauge 919005 ..............................................................................................................86 Table 103. Mitchell River water balance – gauge 919014 ..............................................................................................................87 Table 104. Mitchell River water balance – gauge 919001 ..............................................................................................................87 Table 105. Mitchell River water balance – gauge 919013 ..............................................................................................................88 Table 106. Mitchell River water balance – gauge 919007 ..............................................................................................................88 Table 107. Mitchell River water balance – gauge 919003 ..............................................................................................................89 Table 108. Mitchell River water balance – gauge 919312 ..............................................................................................................89 Table 109. Mitchell River water balance – gauge 919311 ..............................................................................................................90 Table 110. Mitchell River water balance – gauge 919310 ..............................................................................................................90 Table 111. Mitchell River water balance – gauge 919309 ..............................................................................................................90 Table 112. Mitchell River water balance – gauge 919011 ..............................................................................................................91 Table 113. Mitchell River water balance – 919002.........................................................................................................................91 Table 114. Mitchell River water balance – 919006.........................................................................................................................91 Table 115. Mitchell River water balance – 919008.........................................................................................................................92 Table 116. Mitchell River water balance – 919004.........................................................................................................................93 Table 117. Mitchell River water balance – 919009.........................................................................................................................93 Table 118. Mitchell River water balance – 913999.........................................................................................................................94 Table 119. Mitchell River – Streamflow scaling factors for Scenario B ...........................................................................................96 Table 120. Mitchell River – Rainfall scaling factors for Scenario B .................................................................................................96 Table 121. Mitchell River – Evaporation scaling factors for Scenario B ..........................................................................................96 Table 122. Mitchell River – Streamflow scaling factors for Scenario Cwet......................................................................................97 Table 123. Mitchell River – Streamflow scaling factors for Scenario Cmid .....................................................................................97 Table 124. Mitchell River – Streamflow scaling factors Scenario Cdry ...........................................................................................98 Table 125. Mitchell River – Rainfall scaling factors for Scenario Cwet............................................................................................98 Table 126. Mitchell River – Rainfall scaling factors for Scenario Cmid ...........................................................................................99 Table 127. Mitchell River – Rainfall scaling factors for Scenario Cdry ............................................................................................99 Table 128. Mitchell River – Evaporation scaling factors for Scenario Cwet ....................................................................................99 Table 129. Mitchell River – Evaporation scaling factors for Scenario Cmid ....................................................................................99 Table 130. Mitchell River – Evaporation scaling factors for Scenario Cdry .....................................................................................99 Table 131. River system models mean annual water balance under Scenario A..........................................................................101

© CSIRO 2009 River modelling for northern Australia ▪ xi

Figures

Figure 1. Project area, showing AWRC river basin boundaries (white lines), AWRC drainage divisions and project regions............1 Figure 2. AWRC surface water management areas. River modelling catchment shown by red outline.............................................3 Figure 3. Relief map, major rivers, NASY drainage divisions and AWRC river basins ......................................................................5 Figure 4. Surface water – groundwater interactions in northern Australia. Source: Harrington et al. (2009)......................................6 Figure 5. Rainfall, potential evapotranspiration and rainfall deficit maps. Source: Li et al. (2009) .....................................................7 Figure 6. Flow diagram of key workflow elements for NASY surface water assessment. SRN stands for streamflow reporting node9 Figure 7. Example constant monthly scaling factor (white line) and with linear interpolation (red line) (screen capture of IDL output).

Vertical axis is the constant scaling factor value and the horizontal axis is the day number. Note sequence repeats itself each year .........................................................................................................................................................................................13

Figure 8. Schematic of the approximate location of gauging stations, main demand nodes and storages for the Ord system. The MIKE BASIN model extends from streamflow gauge 809302 to the end-of-system..................................................................17

Figure 9. Schematic diagram of MIKE BASIN model for the lower Ord system ..............................................................................18 Figure 10. Donor to target catchment mapping relationships in the Ord-Bonaparte region. Rainfall-runoff modelling gauging

stations (red triangles) and streamflow modelling gauging stations (blue triangles). Donor to target catchment parameter mapping relationships are shown by the black arrows. Inset shows area of calibration rainfall-runoff gauging stations. ...........20

Figure 11. Comparison between NASY and DoW annual inflow to Lake Argyle .............................................................................22 Figure 12. Flow exceedence curve for annual inflows to the Ord River dam for the DoW and the NASY A historical series ...........22 Figure 13. Schematic of the approximate location of gauging stations, main demand nodes and storages for the Flinders river

system model (green lines) and Leichhardt river system model (pink lines) .............................................................................32 Figure 14. Donor to target catchment mapping relationships. Rainfall-runoff modelling gauging stations (red triangles) and

streamflow modelling gauging stations (blue triangles). Donor to target catchment parameter mapping relationships are shown by the black arrows. Inset shows area of calibration rainfall-runoff gauging stations. ...............................................................40

Figure 15. Schematic of the approximate location of gauging stations, main demand nodes and storages for the Flinders river system model (green lines) and Leichhardt river system model (pink lines) .............................................................................47

Figure 16. Donor to target catchment mapping relationships. Rainfall-runoff modelling gauging stations (red triangles) and streamflow modelling gauging stations (blue triangles). Donor to target catchment parameter mapping relationships are shown by the black arrows. Inset shows area of calibration rainfall-runoff gauging stations ................................................................55

Figure 17. Schematic of the approximate location of gauging stations, main demand nodes and storages for the Gilbert system river model ..............................................................................................................................................................................66


Figure 19. Schematic of the approximate location of gauging stations, main demand nodes and storages for the Mitchell river system model ..........................................................................................................................................................................83


Figure 21. Transect of total mean annual river flow in the Ord, Daly, Leichhardt, Flinders, Gilbert and Mitchell river systems under scenarios AN, BN and CN .....................................................................................................................................................100

Figure 22. Transect of relative level of surface water use in the Leichhardt, Flinders, Gilbert and Mitchell river systems under scenarios A and C .................................................................................................................................................................102

Figure 23. Mean monthly flow for the Ord, Daly, Leichhardt, Flinders, Gilbert and Mitchell end-of-systems under scenarios AN, A and C ....................................................................................................................................................................................103

Figure 24. Daily flow exceedance curves for the Ord, Daly, Leichhardt, Flinders, Gilbert and Mitchell river systems. Note the vertical scale bar for the Ord and Daly are GL and the vertical scale bars for the Leichhardt, Flinders, Gilbert and Mitchell are ML. ........................................................................................................................................................................................104

© CSIRO 2009 River modelling for northern Australia ▪ 1

1 Introduction

Northern Australia Sustainable Yields Project overview

The National Water Commission – on behalf of the Council of Australian Governments and in consultation with the

Australian Government Department of the Environment, Water, Heritage and the Arts – commissioned CSIRO to assess

the water resources of northern Australia, covering the Timor Sea and Gulf of Carpentaria drainage divisions and that

part of the North-East Coast Drainage Division which lies north of Cairns (Figure 1).

This project constitutes the first activity under the Northern Australia Water Futures Assessment (NAWFA) and provides

critical information for the Northern Australia Land and Water Taskforce (NALWT).

Figure 1. Project area, showing AWRC river basin boundaries (white lines), AWRC drainage divisions and project regions

The project area comprises 64 Australian Water Resources Council river basins (also known as surface water

management areas), including the Torres Strait Islands, Gulf of Carpentaria islands and Tiwi Islands (Figure 2). Building

on the success of the Murray-Darling Basin Sustainable Yields Project (completed in 2008), the Northern Australia

Sustainable Yields (NASY) Project developed a method for a spatially contiguous and repeatable assessment of water

resources and applied it to assess water resources under four scenarios:

• historical climate (1930 to 2007) and current development

• recent climate (1996 to 2007) and current development

• future climate (~2030) and current development

• future climate (~2030) and likely future development.

Development equated to the use of surface and groundwater supplies and for this project assumed full allocation of

existing (current) and planned (future) water entitlements, as determined by the jurisdictions. Wherever possible, actual

use (generally less than entitlements for northern Australia) was also assessed for modelling and discussion. The project

2 ▪ River modelling for northern Australia © CSIRO 2009

analysed the potential changes in the hydrological regime at sites of important environmental assets (which are often

important social and cultural sites); considered the unique seasonal climate characteristics of northern Australia; and

investigated surface–groundwater interactions. The project also assessed current water storages and storage options,

including groundwater storage, under the different scenarios, but did not carry out a site specific assessment, nor carried

out a storage-yield-reliability assessment.

The NASY project was undertaken as a desktop study. No new data were collected. The project does, however, mark

the first time a consistent, robust and transparent assessment has been carried out across the three jurisdictions of

northern Australia, and the first time models have included an assessment of possible future climate implications.

Scale of reporting

Assessments and subsequent reporting, were undertaken at the region scale, with regions ranging from 45,000 km2 to

165,000 km2, and comprising one or more river basins. Thirteen regions were defined for this purpose (Figure 1).

Modelling, however, is performed at a resolution of about 29 km2 (0.05 by 0.05 degree cells) for rainfall,

evapotranspiration, recharge and runoff analysis, and at variable resolution for the groundwater analyses. These results

were aggregated to the region scale. The 13 regional reports are contained within three drainage division reports (i.e.

Northern North-East Coast Drainage Division, Gulf of Carpentaria Drainage Division and the Timor Sea Drainage

Division) and the results for each region are presented within one of three drainage division reports. These reports are

available online from the project website <www.csiro.au/partnerships/NASY>. The AWRC surface water management

areas are shown in Figure 2.

Science reports

A series of CSIRO Water for a Healthy Country Flagship Science Reports accompanies the division reports1. These

Science Reports contain technical material in support of the results presented in the drainage division reports. This

report provides the technical material to support the river modelling results presented in Section 3.6 of the regional

chapters of the drainage division reports.

Contents of this report

Where possible river system models were used. These models encapsulate descriptions of current infrastructure, water

demands and water management and sharing rules and can be used to assess the implications of the changes in inflows

described in the rainfall-runoff section on the reliability of water supply to users. They may also be used to support water

management planning by assessing the trade-offs between supplies to various competing categories of users. Given the

time constraints of the project and the need to link the assessments to jurisdiction water planning processes, it was

necessary to use the river system models currently used by these agencies. Where information on infrastructure, water

demand, water management and sharing rules or future development were not provided, a river modelling section was

not warranted.

Regions where river system models exist are referred to as Tier A regions. In these regions a variety of metrics are

reported, including water availability, level of consumptive use and storage behaviour of spills. In the Timor Sea Drainage

Division a coupled groundwater-hydraulic model exists for the Daly catchment (coupled MIKE11–FEFLOW), a river

system model exits for the lower Ord (MIKE BASIN) and there is a simple reservoir model for the Darwin River Dam. In

the Gulf of Carpentaria Drainage Division, IQQM river system models exist for the Mitchell, Gilbert and Flinders and

Leichhardt catchments (see Figure 2). No river system models exist in the North-East Coast Drainage Division, north of

Cairns.

This report provides a brief description of the key landscape features, climate, and flow characteristics of the rivers in the

project area (more detailed contextual information can be found in the drainage division reports). This is then followed by

a description of the methods. Technical material supporting the results in the drainage division reports are then

presented on a region by region basis. Key results across all systems are then compared. Detailed results for each river

system are presented in the regional chapters of the drainage division reports. 1 <http://www.csiro.au/partnerships/NASY-Reports.html>


Figure 2. AWRC surface water management areas. River modelling catchment shown by red outline


2 Project area

The Northern Australia Sustainable Yields Project area covers 1.25 million km2. This includes the Timor Sea and Gulf of

Carpentaria Drainage Divisions and the most northern section of the North-East Coast Drainage Division (Figure 1). The

project area comprises 64 surface water management areas (also referred to as river basins) as defined by the

Australian Water Resources Council (AWRC) (Figure 2). This section briefly provides some contextual information on the

physiography, climate and streamflow characteristics of the study region. A brief discussion on data availability is also

included.

2.1 General setting

Northern Australia is a relatively flat region; there are no high mountain ranges, active volcanos or glaciers. The soils

tend to be deeply weathered and often depleted of nutrients (Leeper 1970). In the west of the project area the dominant

topographic feature is the Kimberley Ranges, which consists of rocky and rugged steep sided gorges and ranges (Figure

3). To the south-west the Kimberleys are flanked by the broad alluvial valley of the Fitzroy River. Situated 200 to 300 m

above the adjacent plains, the Arnhem Land plateau is the dominant topographic feature in the northern half of the

Northern Territory. The Arnhem Land plateau is comprised of poorly consolidated Cretaceous sandstones and is

characterised by deep vertical clefts. Although the Gulf of Carpentaria Division is gently bounded to the east by the Great

Dividing Range, the key topographical features in the eastern half of the project area are the Barkly Tablelands and the

Gregory Range, which rise from broad coastal plains. The broad coastal plains of the Gulf region are perhaps one of the

most characteristic features of the north, with grades of less than 1 in 50,000 (AWRC 1976) and extending in excess of

180 km inland. The northern North-East Coast division is characterised by steep coastal escarpments abutting a narrow

coastal plain. As a result the rivers tend to be much shorter and steeper than those found elsewhere across northern

Australia.

The rocks and sedimentary material of northern Australia can be categorised into four broad groups (Petheram and

Bristow 2008) based upon their permeability characteristics 1) crystalline rocks and Palaeozoic and older sedimentary

material; 2) Early to Middle Palaeozoic carbonate rocks (e.g. Daly, Wiso and Georgina Basins); 3) Cainozoic to Mesozoic

sedimentary rocks and geological basins (e.g. Carpentaria Basin, which forms part of the Great Artesian Basin and the

Cretaceous sandstone Money Shoal Basin); and 4) surficial-unconsolidated, non-lithified and predominantly Quaternary

sediments (e.g. Quaternary sands within the Jardine River catchment).

Crystalline rocks and Palaeozoic and older sedimentary material tend to have negligible primary porosity, consequently

groundwater yields are usually small, localised and water quality can be variable. The Early to Middle Palaeozoic

carbonate rocks are of primary interest as a source of water during the dry season. These rocks are characterised by

dissolution cavities near the watertable and primary porosity due to dolomitic recrystalisation. Dissolution features can

act as preferred flow paths and these systems can be very high yielding. Rivers set within these systems, for example

the Daly, Roper, Nicolson and Gregory, tend to have relatively large dry season baseflow. In the southern parts of the

Gulf of Carpentaria spring discharge occurs from the Carpentaria Basin discharge points, although these point discharge

sources do not sustain large dry season flows. The Cretaceous sandstones in the Northern Territory (e.g. Arnhem Land,

Bathurst and Melville Islands) also discharge to perennial streams. The Quaternary sedimentary aquifer systems tend to

be local to intermediate in scale. The primary system of note in northern Australia is the Quaternary sands of the Jardine

River region, which help to sustain large dry season baseflows, the largest in Queensland (Horn, 1995; Horn et al., 1995).

River reaches with known surface water-groundwater interactions are shown in Figure 4.

The groundwater systems of northern Australia are discussed in more detail in the drainage division reports and

Harrington et al. (2009).


Figure 3. Relief map, major rivers, NASY drainage divisions and AWRC river basins


Figure 4. Surface water – groundwater interactions in northern Australia. Source: Harrington et al. (2009)

2.2 Climate

The location of much of the Australian continent under the descending arm of a Hadley cell (which forms the sub-tropical

pressure ridge across the Australian continent) results in an arid interior and approximately two thirds of the continent

being defined as arid or semi-arid (Sturman and Tapper, 2001). To the south of the arid centre the climate is temperate;

to the north tropical. Northern Australia’s climate is characterised by highly seasonal, summer dominated rainfall and

high temperatures and evaporation rates. Spatially, rainfall varies across the study region by more than an order of

magnitude, i.e. from less than 400 mm in the southern parts of the Flinders River catchment to over 4000 mm on the

steep coastal escarpments north of Cairns (North-East Coast) (Figure 5).

Most of northern Australia receives rainfall between December and March as the inter-tropical convergence zone

migrates over the northern extent of the continent and rainfall extends into May and October for few additional areas

(Petheram and Bristow, 2008; Li et al., 2009). The exception to this rule is along the North-East Coast where orographic

uplift along the coastal escarpment ensures both wet season and some dry season rainfall. Rainfall across northern

Australia is primarily generated by local and organised convection and tropical cyclones and or depressions, which can

result in intense rainfall events. Not only is northern Australia observed to have considerably higher daily rainfall

intensities than southern Australia (Leeper, 1970), but these intensities are considered very high on a global scale.

Jackson (1988) found that for the whole of northern Australia except the North-East Queensland coast, rainfall is more

concentrated (with fewer rain days and higher mean daily intensities) than one would predict from monthly totals when

compared to other tropical regions of the world. Rainfall in northern Australia also has high inter-annual variability,

approximately 30 percent higher than other parts of the world of the same climate type (Petheram et al., 2008).


Over much of northern Australia potential evapotranspiration exceeds 2000 mm/year and is extreme (approaching

10mm/day) during the wet season (i.e. southern summer). A consequence of the high evaporation rates is that most of

the study region has a net rainfall deficit (Figure 5).

For the NASY study the wet season is defined as being from 1 November to 31 April. This was chosen as the most

appropriate time period for the entire study area and is the same time period used by the Northern Territory Department

of Natural Resources Environment, The Arts and Sport (NRETAS).

Figure 5. Rainfall, potential evapotranspiration and rainfall deficit maps. Source: Li et al. (2009)


2.2.1 River flow characteristics

The rivers in the study region are all externally draining and are considered to be gaining systems because rainfall is

generally highest near the coast and lowest in the headwater catchments. The streamflow is considerably more seasonal

and has a much higher inter-annual variability of flow than rivers in other parts of the world of the same climate type

(Petheram et al., 2008). Many of the rivers in the study region have a low Base Flow Index (i.e. less than 0.4) and also

have negative (but not significant) auto-correlation of annual flows (Petheram et al., 2008). These characteristics

together with the generally steep shape of flow exceedance curves suggest that the North Australian environment has

limited hydrologic storage capacity. There are exceptions, however. These exceptions are most prevalent where rivers

are set in the dolomitic limestone of the Northern Territory and western Queensland, Cretaceous sandstones in the

Northern Territory and Quaternary sands of northern Cape York (Figure 4). Tidal ranges in northern Australia are large

relative to southern Australia with, for example, some parts of the Kimberleys experience a tidal range of more than 10 m.

As a consequence of the large tidal range, flat coastal topography and low dry season flow, salt water penetrates long

distances (>100 km) inland for many northern Australian rivers.


3 Methods

3.1 General approach

The surface water assessment, for which the river system modelling was one component, involved seven separate tasks:

1. gauging station selection and data preparation

2. rainfall-runoff modelling at the regional scale for scenarios A, B and C

3. river system modelling

4. river flow assessment for regions without river models

5. estimation of the ‘level of confidence’ for the model results

6. an alternative approach using regression analysis to compute key hydrological metrics

7. comparison of flow characteristics estimated using the rainfall-runoff modelling approach against flow

characteristics estimated using an empirical approach.

This report details the method used to undertake task 3 (green polygon in Figure 6). Tasks 1, 2, 4 ,5 and 7 (blue polygon)

are described by Petheram et al. (2009). A brief overview of tasks 1 and 2 are provided in this report for context. Task 6,

the regression analysis (yellow polygon), was undertaken at the whole of northern Australia scale. A detailed description

of the regression analysis is provided by SKM (2009).

Figure 6. Flow diagram of key workflow elements for NASY surface water assessment. SRN stands for streamflow reporting node


3.1.1 Preparation of climate data

The rainfall-runoff modelling utilised 0.05 degree (approximately 5 x 5 km) gridded daily rainfall and APET data. The use

of a 0.05 degree grid allowed the best representation of the spatial patterns and gradients in rainfall, allowing an

improved representation of the non-linear relationship between rainfall and runoff.

The 0.05 degree gridded daily rainfall and APET data across northern Australia were compiled (i.e. obtained, analysed

and prepared see Li et al., 2009) between the 1 September 1930 and 31 August 2007 from the SILO gridded data

(Jeffrey et al., 2001 and <www.nrm.qld.gov.au/silo>). APET was computed from the SILO daily climate surfaces using

Morton’s wet environment evapotranspiration algorithms (see <www.bom.gov.au/climate/averages> and Chiew and

Leahy, 2003). These data constituted the Scenario A or historical climate sequence. The 0.05 degree grid cells were

then mapped into each gauged catchment and streamflow reporting node (SRN).

Scenario B climate data (recent climate sequence from 1 September 1996 to 31 August 2007) were obtained from the

last 11 years of the historical climate sequence (i.e. Scenario A). Scenario C climate data (future ~2030 climate) were

generated by scaling the historical climate sequence, informed by 15 global climate models (GCMs) for three emissions

scenarios (equivalent to low, medium and high global warming scenarios). This provided 45 series of 77 years of daily

rainfall and APET (i.e. one climate series from each of the 15 GCMs for each of the low, medium and high global

warming scenarios). A comprehensive description of the methods used to generate the climate scenarios is provided by

Li et al. (2009).

3.1.2 Digital elevation model and flow direction grids

Version 3 of the GEODATA 9 second flow direction grid, derived from version 3 of the GEODATA 9 second digital

elevation model (Hutchinson et al., 2008) was used to define catchment boundaries for each gauging station and each

model reach. Note that at latitudes corresponding to the NASY study region, 9 arc-seconds corresponds to a horizontal

distance of approximately 270 m. The flow direction grid represents the aspect of the downslope direction at each DEM

grid point, calculated from the relative heights of the neighbouring grid points.

A modelled ‘stream network’ was generated from the nine second flow direction grid across the NASY study region using

flow-accumulation algorithms and a nominal threshold area. This stream network was generated principally for the

purposes of locating (a) the calibration catchment gauges and (b) streamflow reporting nodes (SRN) onto the DEM-

derived flow paths such that appropriate upstream catchments could be defined for each from the nine second flow

direction grid.

3.1.3 Rainfall-runoff modelling

Rainfall-runoff modelling scenarios

The rainfall-runoff modelling was used to generate 77 years of daily runoff at the SILO grid cell scale for three scenarios:

• Scenario A (historical climate sequence from 1 September 1930 to 31 August 2007 and current development) –

one simulation based on the historical climate series

• Scenario B (recent climate sequence from 1 September 1996 to 31 August 2007 and current development) –

one simulation of the climate from the past 11 years run seven consecutive times (to produce 77 years of

record)

• Scenario C (future ~2030 climate and current development)

Scenario D runoff simulations were not undertaken because projections of growth in commercial forestry and farm dams

were negligible (see Petheram et al., 2009).

Two rainfall-runoff models were utilised in this project: Sacramento and IHACRES Classic. The Sacramento and

IHACRES Classic models were calibrated to streamflow data from 144 streamflow gauging stations, which were

considered to be of relatively high quality. Parameter values for cells in ungauged catchments were based on a

combination of values from the closest, or most hydrologically similar, grid and/or catchment where calibration was


possible (e.g. Merz and Bloschl, 2004; Chiew and Siriwardena, 2005; Reichl et al., 2006). All grid cells within the

contributing area of a SRN were allocated the same parameter values. Runoff was then simulated for every reach within

the river system models under the above scenarios, using the ensemble of Sacramento and IHARCES Classic

(i.e. averaging the results). See Petheram et al. (2009) for more detail.

3.1.4 River system modelling

Overview

River system models can be used to assess the implications of the changes in inflows on the reliability of water supply to

users. They may also be used to support water management planning by assessing the trade-offs between supplies to

various competing categories of users. These models describe infrastructure, water demands, and water management

and sharing rules. Given the time constraints of the project, and the need to link the assessments to state water planning

processes, it is necessary to use the river system models currently used by state agencies.

Six river system models and a coupled FEFLOW – Mike 11 model (i.e. hydraulic model) were available for use in this

project. The FEFLOW – Mike 11 model was developed for the Daly River catchment by NRETAS (Knapton 2006) and its

application to the Daly for the NASY project is described in detail by Knapton et al. (2010). Consequently this model will

not be discussed further in this report. Of the six river system models, four were the Integrated Quantity and Quality

Model (IQQM) (Mitchell, Gilbert, Flinders and Leichhardt), one was a MIKE BASIN model (lower Ord River system) and

one was a simple spreadsheet reservoir model (Darwin River Dam). Set-up information specific to each model is

described in the Section 3.2.

The river system modelling methods section below outlines how the river system inflow and climate data were scaled.

The GCMs for the river modelling scenarios were selected based on the rankings of mean annusl rainfall (see Li et al.,

2009).

The river modelling results are reported using a range of metrics, which were consistently applied across all regions. The

use of a common set of metrics across the entire project area enables comparisons between regions. A brief definition of

the key metrics is provided.

Method for scaling inflows and climate data

Runoff within each reach of the river system models was modelled using the ensemble runoff simulated using the

Sacramento and IHACRES Classic models, as described in Section 3.1.3. However, with the exception of the MIKE

BASIN model, the modelled ensemble runoff series were not used directly as subcatchment inflows in the river system

models. Doing so would compromise the calibrations of the river system models, which were based on different runoff,

rainfall and evaporation climate series.

Instead, the relative difference between the average monthly runoff values (interpolated between months using a linear

interpolation) under the historical climate (Scenario A) and the remaining scenarios (scenarios B and C), normalised to

the average annual values of these scenarios, were used to modify the existing inflows series in the river system models

(see Equations 1–5). Scenarios B and C inflow series to the river system modelling therefore have the same daily

sequences, but different amounts, as the Scenario A river system modelling series. The same method was applied to

rainfall and evaporation data.

Constant seasonal scaling factors (three month long seasons) were also investigated. However, constant seasonal

scaling factors were similar to constant monthly scaling factors in terms of maintaining annual scaling. Hence the

constant monthly scaling factors were used because they provided a better temporal resolution in scaling values.

Equation 1 was used to compute an average monthly scaling factor (mXS ) where X represents Scenario X (an arbitrary

scenario) and m a month 1 through 12. For each month (m), the total rainfall-runoff model runoff under Scenario X was

divided by the total rainfall-runoff model runoff under Scenario A (i.e. over the entire 77 year (y) sequence). In Equation 1,

Xm (Am) is the runoff during month m under Scenario X (A) for a single year.


∑

∑

=

=

=

=

Α=

77

1

77

1

y

ym

y

ym

X

X

Sm

(1)

Equation 2 was used to compute the mean annual scaling factor (aXS ). The total rainfall-runoff model generated runoff

under Scenario X was divided by the total rainfall-runoff model runoff under Scenario A (i.e. over the 77 year (y)

sequence). In Equation 2, Xa (Aa) is the runoff under Scenario X (A) over an entire year.

∑

∑

=

=

=

==77

1

77

1

y

ya

y

ya

X

A

X

Sa

(2)

To assess how well the annual scaling (aXS ) was maintained once the constant monthly scaling factors (

mXS ) were

applied to the monthly river model inflows we used Equation 3 to compute the ‘monthly summed’ mean annual scaling

factor (aXS ′ ). A’m are the original river model inflows for month m.

( )

∑∑

∑∑

=

=

=

=

=

=

=

=

Α′

Α×=′

77

1

12

1

77

1

12

1

'

y

y

m

mm

y

y

m

mmX

X

m

a

S

S (3)

Equation 4 was used to adjust the constant monthly scaling factor (mXS ) in order to maintain annual scaling.

mXS ′ is the

adjusted constant monthly scaling factor.

a

a

mm

X

X

XX S

SSS

′×=′ (4)

To minimise the potential for large step changes in flow occurring at the start and end of each month (e.g. if there was a

large difference in constant monthly scaling factors between months m and m+1), a linear interpolation scheme (i.e.

boxcar average smoothing function – ‘smooth’ function in interactive data language (IDL) with 15 day window) was

applied to the monthly values of mXS ′ (white line in Figure 7) to generate a constant daily scaling factor for every day of

the year, dXS ′ (red line in Figure 7). In the case of a leap year, February 29 was assigned the same value as February

28.


Figure 7. Example constant monthly scaling factor (white line) and with linear interpolation (red line) (screen capture of IDL output).

Vertical axis is the constant scaling factor value and the horizontal axis is the day number. Note sequence repeats itself each year

Equation 5 was used to generate daily inflows to the river model (X’ d ) under Scenario X. This was done by multiplying

each day of inflow sequence A’ d by the appropriate value of dX

S ′ .

dXdd SX ′×Α′=′ (5)

For the Ord MIKE BASIN model, the modelled ensemble runoff series from Sacramento and IHACRES Classic were

used directly as subcatchment inflows to the model (see Section 3.2.1). Rainfall and evaporation data were also input

directly to the model.

Timeperiod for reporting results

In this report where annual data are reported, years are represented by numbers 1 through 77. Consistently throughout

the project, annual data are based on the water year (1 September to 31 August) and the dry season is defined as 1 May

to 31 October. Scenarios Cwet, Cmid and Cdry are selected on the basis of the ranked mean annual rainfall for the

modelled subcatchments.

Degree of regulation

The degree of regulation metric presented is defined in this project to be the sum of the net evaporation and controlled

releases from the dam divided by the total inflows. Controlled releases exclude spillage. Storages with radial gates and

without spillways are not reported.

Water availability

In the Murray-Darling Basin Sustainable Yields Project, water availability was defined as the volume of water under the

without-development scenario, which occurs at the point of maximum mean annual flow along a river system. This

generally occurred where a river system turned from a gaining reach to a losing reach. The major rivers in northern


Australia are, however, gaining systems. This means that their highest mean annual flow occurs at their end-of-system.

However, end-of-system flow volumes are often uncertain due to considerable ungauged flow contribution to these points.

For this reason in the NASY project water availability was defined as the volume of water under the without-development

scenario which occurs at the gauged point of maximum mean annual flow along a river system. In the river systems of

the northern Australia this point occurs at the most downstream gauge. When computing water availability for this project,

ecological, social, cultural and economic values were not considered.

It must also be noted, however, that not all of the water at the most downstream gauge is accessible for consumptive use.

In the Gulf of Carpentaria, for example, the majority of suitable locations for large carry over storages are in the

headwater catchments and not at or near the last gauge in the system. Further, during large overbank flows (flood flows),

water harvesting operations, which are usually located in the lower reaches, are constrained by the rapid rise and fall in

river height (Petheram et al., 2008) and insufficient on-farm storage capacity.

Spills from reservoirs

A spill commences when the storage exceeds full supply volume and ends when the storage falls below 90 percent of full

supply volume. The end condition is applied to remove the periods when the dam is close to full and oscillates between

spilling and just below full which would otherwise distort the analysis. The period between spills is the length of time from

when one spill ends (i.e. storage falls below 90 percent of the full supply volume) until the next spill commences (i.e.

when the storage exceeds the fully supply volume).

Level of use

The level of use metric used in this project was indicated by the ratio of total use to surface water availability. Total use

comprises subcatchment and streamflow use. Subcatchment use (e.g. commercial forestry, farm dams) was considered

negligible for the river systems of northern Australia. Streamflow use includes total net diversions, which are defined as

the net water diverted for the full range of water products.

Level of use is presented in two ways in this report. The first, the same as for the Murray-Darling Basin Sustainable

Yields Project, is the ratio of total use to total surface water availability. The second is as a transect of level of use at

each main river gauge with use being the cumulative use up to the gauge including use on effluents and tributaries

compared with the average annual river gauge.


3.2 River model specific information

This section presents information specific to the individual river models. A brief description of each model is provided.

Reach water balances and scaling factor tables are then presented. In the case of the Ord MIKE BASIN model, the

project runoff estimates were used as direct input to the model. Therefore a brief comparison is provided of project and

Department of Water runoff estimates. Detailed results can be found in the river modelling chapters of the drainage

division reports.

3.2.1 Ord

Model overview

The Ord River and reservoir system is described by a numerical model using MIKE BASIN software (Danish Hydrologic

Institute). The model was developed by the Western Australia Department of Water (DoW) to establish and refine

operating rules for the Ord River Dam using an historical climate and streamflow dataset and a range of possible future

development scenarios. Results from this model for the period from January 1906 to December 2004 were used to

establish the operating rules and system targets for the Ord River Dam (ORD).

The MIKE BASIN model for the Ord has been used in this project to assess thirteen scenarios:

• Scenario A – historical climate sequence and current development

This scenario incorporates the effects of current land use. Modelling commences on the 1 September 2007 and

streamflow metrics are produced by modelling the 77-year historical climate sequence between 1 September

2007 and 31 August 2084. This scenario is used as a baseline for comparison with all other scenarios.

• Scenario AN – historical climate sequence and without-development

Current levels of development such as public storages and demands are not considered when determining

without-development conditions. Inflows were not modified for groundwater extraction, major land use change

or farm dam development because the impact of these factors on catchment yields in this region is considered

to be negligible. Without-development flows for the system were derived by adding the upstream catchment

inflows for the Ord River, Kununurra River and Dunham River.

• Scenario BN – recent climate and without-development

This scenario assuming without-development conditions (as per Scenario AN) and uses seven consecutive 11-

year climate sequences between 1 September 1996 and 31 August 2007 to generate 77-year time series for

runoff and climate. See Li et al. (2009) for more detail.

• Scenario CN – future climate and without-development

Scenarios Cwet, Cmid and Cdry represent a range of future climate conditions assuming without-development

conditions (as per Scenario AN).

• Scenario B – recent climate and current development

This scenario incorporates the effects of current land use and uses seven consecutive 11-year climate

sequences between 1 September 1996 and 31 August 2007 to generate 77-year time series for runoff and

climate.

• Scenario C – future climate and current development

Scenarios Cwet, Cmid and Cdry represent a range of future climate conditions assuming current levels of

development. Rainfall-runoff results from Section 3.1.3 were input directly into the MIKE BASIN model.

• Scenario D – future climate and 2030 development

Scenarios Dwet, Dmid and Ddry represent a range of future climate conditions for a 2030 development scenario.

The future development is representative of a 400 GL increase in allocation for the M2 irrigation area.

Projections of commercial forestry and farm dams for 2030 are negligible and hence no adjustments were made

to the Scenario C runoff time series.


The project scenario simulations use comparable but different initial conditions and inflow time series and a shorter

simulation period than what was used by the DoW to establish reservoir operating rules and system targets. Results from

these scenarios are not intended to be directly comparable with the department’s simulations.

The changes in inflows between scenarios reported in this section may differ from the changes in runoff reported in the

drainage division reports. These differences are due to difference in the methods by which the GCMs were ranked and

difference in areas that are considered to contribute runoff to the surface water model. In the rainfall-runoff chapter of the

Timor Sea Drainage Division report the entire region was considered while a subset of this area was considered here.

The scenarios presented in this project may not eventuate but they encompass consequences that might arise if no

management changes are made. Consequently results from this assessment are designed to highlight pressure points in

the system, both now and in the future. This assessment does not elaborate on what management actions might be

taken to address any of these pressure points. Where management changes to mitigate the effects of climate change

have recently been implemented, the impacts of the changes predicted in this section may be an overestimate.

River model description

The model extends from the Ord River Dam, which forms Lake Argyle, down to the confluence of the Ord and Dunham

rivers. This area encapsulates the Ord River Irrigation Area and the Kununurra Diversion Dam, which forms Lake

Kununurra. Inputs to the MIKE BASIN model include daily time series of runoff, rainfall and evaporation and water

demand rules. The hydrological features of the Ord River system are described by daily time series of catchment runoff

from the area upstream of the Ord River Dam, runoff from the area between the Ord River Dam and the Kununurra

Diversion Dam, and runoff from the Dunham River (Figure 8). Spatially averaged daily time series of rainfall and

evaporation data are used to compute the net evaporation from Lake Argyle and Lake Kununurra. Monthly irrigation

demand over the Ord River Irrigation Area is varied for each scenario based on rainfall and evaporation data.

There are two major storages in the Ord system, the previously mentioned Ord River Dam and the Kununurra Diversion

Dam. The Ord River Dam is the major storage providing water for various downstream users. It has an active storage of

10,380 GL (Table 1 presents details for the Ord River Dam). The Kununurra Diversion Dam is a re-regulating storage

downstream of the Ord River Dam. It has an active storage volume of 105 GL, less than 1 percent of the Ord River

Dam’s active storage volume. The degree of regulation metric is defined in this project to be the sum of the net

evaporation and controlled releases from the dam divided by the total inflows. Controlled releases include water for

irrigation demands, for hydropower generation and for environmental water provisions, but exclude spills. The degree of

regulation for the Ord River Dam is 0.8, which is very high. It is not appropriate to calculate the degree of regulation for

the Kununurra Diversion Dam, which is a re-regulating structure.

The MIKE BASIN model includes three water users: (i) hydropower generation; (ii) irrigation; and (iii) environmental water

provisions (EWP). Irrigation demands are represented on a monthly basis and environmental water provision on a daily

basis. Hydropower demands at the Ord River Dam are specified as monthly power generation targets; the water required

to produce these targets depends on water levels in Lake Argyle.

In the case of irrigation and environmental demands, water is drawn from Lake Kununurra, but the restriction policies for

these demands are based on water levels in Lake Argyle. This is represented in the model by dummy demand nodes at

Lake Argyle, where water restrictions are set, in addition to the demand nodes at the Kununurra Diversion Dam, where

water is taken from the system.

Reservoir operating rules define levels in Lake Argyle where restrictions may apply to hydropower, irrigation and

environmental water allocations. These rules seek to ensure that water supplies are reliable and that the water level in

the reservoir is not lowered below a minimum operating level (particularly in drought sequences). The department has

determined operating rules for current and future allocation situations on the Ord. The current situation includes a 350 GL

allocation for the M1 irrigation area, while the future includes an extra 400 GL allocation for the M2 irrigation area. Other

demands (which remain identical between the two situations) include hydropower and environmental water.

It should be noted, however, that these simulations have been undertaken to reflect differences between climate and

development scenarios, and are not consistent with or designed to be directly comparable with the department’s

simulations

The modelled water use configuration is summarised in Table 2. In this table the target power generation is the minimum

commitment to be provided when Lake Argyle is above 78 m AHD.


The Ord River Dam operating rules were developed from results of simulations based on the Department of Water’s 98-

year historical climate and streamflow dataset. Rules were derived so that the following target outcomes were achieved

as closely as possible:

• a 95 percent probability of supplying the full annual irrigation demand

• the minimum annual irrigation supply to be restricted to no less than 25 percent of demand

• a minimum water level in the reservoir of 70 m AHD.

Figure 8. Schematic of the approximate location of gauging stations, main demand nodes and storages for the Ord system. The MIKE

BASIN model extends from streamflow gauge 809302 to the end-of-system

The model schematic for the Ord River system, including subcatchments and river branches is shown in Figure 9. Water

demand nodes (represented by the orange house icons) exist for the irrigation areas, environmental water provision and

hydropower stations.


Figure 9. Schematic diagram of MIKE BASIN model for the lower Ord system


Table 1. Major storage in the Ord river system model

Active storage Average annual Inflow

Average annual release

Average annual net evaporation


GL GL/y

Major storage

Ord River Dam 10,380 4257 2417 993 0.80

Table 2. Modelled water use configuration in the Ord system

Water users Number of nodes

Allocation or Target

Model notes

Irrigation

Current development 2 350 GL/y Monthly demand for M1 and M1 growth areas

Future development 3 750 GL/y Monthly demand for M1, M1 growth and M2 Irrigation

Hydropower 1 210 GWhr Instream

Environmental water provision Instream

The environment water requirements and environment water provision for the lower Ord River are provided in the Ord

Chapter of the Timor Sea Drainage Division report (CSIRO, 2009).

Model setup

Operating rules developed by DoW were applied to all of this project’s scenarios. Rules and demands for the 350 GL

allocation scenario have been applied to scenarios A, B and C, while rules for the future development, 750 GL/year, are

used for Scenario D. All scenarios have been simulated with a starting water level in Ord River Dam of 91.35 m AHD,

which is the level measured on 1 September 2007.

Without-development flows at the confluence of the Ord and Dunham rivers were derived by adding the catchment

inflows to Lake Argyle and Lake Kununurra to the flows from the Dunham River.

Table 3 summarises the setup information for the Ord river system model.

Table 3. Ord river system model setup information

Model setup information Version Start date End date

Ord MIKE BASIN 2005 1/01/1906 31/12/2004

NASY simulation period

MIKE BASIN 2005 1/09/2007 31/08/2084

Modifications

Data

Inflows Simulated runoff used

Initial storage levels

Ord River Dam 91.35 m AHD

Kununurra Diversion Dam 41.9 m AHD

Model input

Inflow and climate data generated by the Northern Australia Sustainable Yields Project were input directly to the MIKE

BASIN model. No constant monthly scaling was undertaken.


Inflows to Lake Argyle were modelled by the flow at SRN 809302. Inflows that occurred between Lake Kununurra and

Lake Argyle were modelled by SRN 60014. Discharge from the Dunham was modelled using the flow at SRN 809340.

Average daily climate data were generated by averaging the SILO climate data over Lake Argyle, Lake Kununurra and

the ORIA. Target to donor catchment mapping is illustrated in Figure 10 (see Petheram et al., 2009). SRN 60014 was

modelled by using the parameters from (donor) gauges 809340 and G8100189. An average of the two model results was

used to simulate the inflows to the MIKE BASIN model at this node.

Figure 10. Donor to target catchment mapping relationships in the Ord-Bonaparte region. Rainfall-runoff modelling gauging stations (red

triangles) and streamflow modelling gauging stations (blue triangles). Donor to target catchment parameter mapping relationships are

shown by the black arrows. Inset shows area of calibration rainfall-runoff gauging stations.

DoW inflow sequence to Lake Argyle

The DoW historical inflow series to Lake Argyle was developed using a combination of estimates of streamflow from

catchment rainfall (pre-1955), recorded stream flow (1955 to 1971) and reservoir water balance (1972 to 2004). The

inflow series were initially monthly, however monthly totals were disaggregated into daily stream flow using results from

hydrologic modelling (LUCICAT) of the catchment (Bari and Rodgers, 2006). The LUCICAT (Land Use Change

Incorporated CATchment) model was used to simulate daily runoff in the Ord River catchment from 1905 to 2004. The

model was calibrated to streamflow data from 7 gauging stations for the period 1970 to 2003 and model validation was

carried out for the period 1955 to 1970 using data from the Coolibah Pocket (809302) gauging station (i.e. the site of the

current Ord River dam wall).


Methods used to estimate the historic monthly flow series prior to 1955 are not well documented. However, the following

approach was commonly used by Public Works Department hydrologists during the late 1960s, when the estimates are

understood to have been made.

Graphical relationships between monthly ‘effective rainfall’ and monthly runoff were normally developed for each gauged

catchment (i.e. a catchment with a stream gauging station at its outlet). ‘Effective’ monthly rainfall was defined as a linear

combination of the current month’s rainfall, and the previous two or three month’s rainfall. Rank correlation techniques

were often used to determine the ‘best’ linear combination of current and previous rainfall. The technique involved

selecting an ‘effective monthly rainfall’ that minimised the scatter in the consequent relationship between 'effective

rainfall' and runoff.

The ‘effective rainfall’ runoff relationship derived for the Ord Catchment would have been based on streamflow data

recorded between 1955 and the mid 1960s. This period included both wet (1959) and dry (1964) years.

It is understood that monthly catchment rainfalls for the Ord catchment were derived from BoM’s rainfall records in the

following way. Monthly rainfalls recorded at individual stations in the region were plotted, isohyets drawn across the

catchment and averages calculated based on the isohyets. The approach involved close examination of the recorded

data and enabled missing records at individual stations to be accounted for (if subjectively). While the resulting monthly

catchment rainfalls are not available, it is understood that they were determined from 1906 to the late 1960s in this

manner.

The DoW believes the monthly rainfall sequence used to establish the ‘effective’ rainfall runoff relationship and extend

historical flows back to 1906 to be relatively reliable. The DoW has, however, less confidence in the adequacy of the

monthly ‘effective’ rainfall runoff relationship of the Ord catchment, as derived in the late 1960’s. However, as the

relationship was based on records for the mid-1955 to 1960s period, and this included both wet (1959) and dry (1964)

years, there is no obvious reason for the relationship to be biased to wet or dry conditions, or to over-predict runoff in dry

years.

Comparison of DoW and NASY inflow series

Scenario A represents the historical climate from 1 September 1930 to 31 August 2007, applied to the Ord River system

from 1 September 2007. Climate in the 1930’s was relatively dry, and this has been applied to particularly wet initial

conditions in the reservoir (a high starting water level of 91.35 m AHD).

Using the Northern Australia Sustainable Yields Project Scenario A inflow sequence, the MIKE BASIN model simulation

met all of DoW’s target outcomes (minimum water level, reliability and minimum supply of irrigation water). However,

there was one year where irrigation supply was much more severely restricted than any other. This resulted from the

Scenario A inflow series to Lake Argyle containing a very low inflow year after several below average inflow years.

Comparison between annual (November to October) inflows to Lake Argyle for the Northern Australia Sustainable Yields

Project Scenario A and DoW’s historical series over the common period 1930-31 to 2003-04 is shown in Figure 11. The

two series are distributed evenly around the 1:1 line, indicating that the hydrologic estimates were similar and not biased

at the wet or dry end of the scale (Figure 4).


0

2000

4000

6000

8000

10000

12000

14000

16000

18000

20000

0 2000 4000 6000 8000 10000 12000 14000 16000 18000 20000

DoW annual inflow (GL)

NA

SY

an

nu

al i

nfl

ow

(G

L)

1:1

Figure 11. Comparison between NASY and DoW annual inflow to Lake Argyle

However, the driest 6 per cent of years of the Northern Australia Sustainable Yields Project Scenario A inflow series

tended to be lower than DoW’s historical series (Figure 12. Flow exceedence curve for annual inflows to the Ord River

dam for the DoW and the NASY A historical series). Restriction severity is strongly influenced by these driest inflow

years. In consequence, the Northern Australia Sustainable Yields Project Scenario A simulations generate more severe

restrictions than comparable simulations based on the department’s historical series. Similar differences would be

expected for the other Northern Australia Sustainable Yields Project scenarios.

50.0

%

99.5

%

99.0

%

98.0

%

95.0

%

90.0

%

80.0

%

20.0

%

10.0

%

5.0%

2.0%

1.0%

0.5%

0.2%

0.1%

99.8

%

100

1000

10000

100000

Probability (%)

Dai

ly fl

ow (

ML)

DoWNASY

Figure 12. Flow exceedence curve for annual inflows to the Ord River dam for the DoW and the NASY A historical series

Scenario B incorporated a repeated series of the last 11 years of climate data. In the Ord region, this period was a time

of high rainfall and streamflow. The mean annual rainfall for Scenario B over the 77 year period was between 18 and 34

per cent higher than Scenario A, and potential evaporation was 1 per cent lower than the Scenario A. Mean annual

streamflow was between 63 and 82 per cent higher than for Scenario A.


River system water balance – whole of system

The mass balance table (Table 4) shows volumetric components for Scenario A as GL/year, with all other scenarios

presented as a percentage change from Scenario A. Mass balance includes the change in storage that is averaged over

the 77-year period and is shown as GL/year.

Most of the inflows were based on data from a river gauge. The indirectly gauged inflows are from the area between the

Ord River Dam and the Kununurra Diversion Dam. End-of-system flows are shown for the Ord River just below the

confluence of the Ord and Dunham rivers (Figure 8).

Mass balance was checked by taking the difference between total inflows and outflows of the system. In all cases the

mass balance variance was less than 1 percent of the inflows.

Table 4 shows that under scenarios Cwet and Cdry, inflows increase 19 percent and decrease 22 percent respectively.

Compared to the change in inflows there is a larger change in flow at the end-of-system, a 27 percent decrease under

Scenario Cdry. The impact to diversions is relatively small under Scenario C. Under scenarios Dwet, Dmid and Ddry, the

additional irrigation water use results in a 114, 113 and 98 percent increase in diversions respectively. This assessment

does not consider water products other than water that is diverted from the river.

The large increase in inflows under Scenario B is due to the statistically significant increase in rainfall under the recent

climate relative to the historical climate (Scenario A). See Li et al. (2009) for more detail.

Net evaporation from Lake Argyle (Table 1) is a large proportion of the average annual inflow to the lake (approximately

23 percent) and controlled releases (approximately 41 percent).

Not surprisingly, the MIKE BASIN results for Scenario B reflect the period of high rainfall and streamflow. Irrigation and

environmental water demands were met in all years, the minimum water level in Lake Argyle was 86.3 m AHD (16.3 m

above the minimum operating level), and mean annual hydropower generation was the largest of all scenarios at 300

GWhrs/yr (Table 5).

Scenario Cwet had a 4 to 5 percent increase in mean annual rainfall and potential evaporation compared to Scenario A.

There was a corresponding 14 to 20 percent streamflow increase for this scenario. With a wet future climate, irrigation

and EWP reliabilities, minimum water level and hydropower production were all well above the department’s targets, but

still not as great as under Scenario B.

Scenario Cmid had 2 percent higher mean annual rainfall and potential evaporation compared to Scenario A. There was

a corresponding 2 to 3 per cent streamflow increase for this scenario. This scenario was most similar to the Scenario A in

terms of irrigation reliabilities and hydropower produced. It should be noted, however, that despite the slightly higher

streamflow and rainfall averages, the irrigation reliabilities and minimum water levels were slightly lower than under

Scenario A. Hydropower production and EWP reliability were slightly higher.

Under Scenario Cdry there was a 13 per cent decline in mean annual rainfall and 5 per cent increase in potential

evaporation compared to Scenario A. There was a 21 to 25 percent decrease in mean annual streamflow compared to

Scenario A. Under Scenario Cdry the minimum water level and irrigation reliabilities were below the threshold levels used

by DoW to determine operating rules. For instance, the minimum water level of 64.5 m AHD is 5.5 m below the minimum

operating level of 70 m AHD. The minimum irrigation supply was 10.5 percent which is well below the target of 25 per

cent, while supply reliability was well below 95 percent, at 83.3 percent.

Rainfall, evaporation and streamflow were identical between scenarios Cdry and Ddry, Cmid and Dmid, and Cwet and

Dwet. However, under Scenario D an additional irrigation allocation (for the M2 area) was assigned to the Ord River

region. DoW determined different reservoir operating rules for the 400 GL allocation, and these have been applied to the

Scenario D simulations. This means that scenarios C and D cannot be directly compared. However, a general

comparison shows that there was extra strain on the system under Scenario D, particularly in dry years with the minimum

irrigation supply and minimum water level in the reservoir consistently lower than for the corresponding Scenario C

(Table 5). Slightly less power was generated with the extra irrigation allocation; this may be due to the tighter restriction

policies applied to this scenario.


Table 4. Ord river system model mean annual water balance under Scenario A and under scenarios B, C and D relative to Scenario A

A B Cwet Cmid Cdry Dwet Dmid Ddry

GL/y

Storage volume

Change over period 5.8 5.8 8.7 4.0 -2.9 8.7 4.0 -1.7

GL/y percent change from Scenario A

Inflows

Subcatchments

Gauged 4832.2 70% 19% 3% -22% 19% 3% -22%

Ungauged 115.8 62% 16% 3% -21% 16% 3% -21%

Sub-total 4948.1 70% 19% 3% -22% 19% 3% -22%

Diversions

Irrigation 348.3 1% 1% 0% -7% 114% 113% 92%

Sub-total 348.3 1% 1% 0% -7% 114% 113% 92%

Outflows

End-of-system flow 3593.8 95% 23% 3% -27% 11% -9% -37%

Sub-total 3593.8 95% 23% 3% -27% 11% -9% -37%

Net evaporation

Lake Argyle 992.9 4% 11% 4% -8% 15% 5% -8%

KDD 17.9 -14% 3% 3% 16% 3% 3% 16%

Sub-total 1010.7 4% 11% 4% -8% 15% 5% -7%

Mass balance variance relative to total inflows (percent)

-0.2% -0.1% -0.2% -0.2% -0.5% -0.2% 0.2% -0.7%

Table 5. Summary table for Ord system

Scenario Hydropower M1 Irrigation M2 Irrigation Lake Argyle EWP

Mean annual

power Minimum

supply Reliability Minimum

supply Reliability Minimum water

level Reliability

(GWhr) (%) (%) (%) (%) (m AHD) (%)

A 238.8 34.8 97.4 Na Na 70.1 92.2

B 300.4 100 100 Na Na 86.3 100

Cdry 191.5 10.5 83.3 Na Na 64.5 74

Cmid 241.9 32.3 96.2 Na Na 69.8 94.8

Cwet 258.9 82.4 98.7 Na Na 74.5 97.4

Ddry 186.4 10.5 76.9 11.4 76.9 64.4 66.2

Dmid 232.3 12.5 96.2 12.7 97.4 67.7 89.6

Dwet 246.2 44.6 98.7 43.8 98.7 71.5 96.1

The simulation results indicate that under scenarios Cmid and Dmid the Ord River Dam and the Kununurra Diversion

Dam could be operated satisfactorily with the current and planned reservoir operating rules. The modelling indicates that

under Cmid little change in hydro-electricity generation, reservoir behaviour or irrigation supply outcome will occur.

Under Scenario Cwet additional hydro-electricity could be generated. Under Scenario Dwet water could be supplied at

very high reliabilities. Alternatively, revised operating rules could be developed to make more water available, for either

hydro-power or irrigation.

The current reservoir operating rules would need to be modified under scenario Cdry or Ddry. A number of options are

available including adjusting hydro-power release rules, reducing water available for irrigation expansion, accepting lower

reliabilities of supply, and reconsidering the environmental flow objectives given a changed climate.

However, under scenarios Cdry and Ddry the severity of drought may be too severe. The driest six percent years in the

NASY A inflow series were considerably lower than the DoW historical series (see Figure 12). Further work would be

required to validate the dry inflow years of the NASY A series and develop a revised set of reservoir operating rules

under a dry climate scenario. Such work should be undertaken as part of developing future Ord River water allocation

plans and if further research demonstrates that the climate is likely to dry.


3.3 Darwin river reservoir

Model overview

A model of the Darwin River Dam was set up as a daily water balance in Microsoft Excel (SKM 2005). The model was

developed in 2005 and calibrated to historical climate, storage levels, release and extraction information. The model was

originally developed for a simulation period from 1 July 1900 to 28 February 2003. The model period was extended as

part of the Northern Australia Sustainable Yields Project to include data up to 31 August 2007.

The Darwin River Dam model has been used in the Northern Australia Sustainable Yields Project to assess thirteen

scenarios:

• Scenario A – historical climate sequence and current development

This scenario incorporates the effects of current land use and uses a constant demand where the daily pattern

is based on historical extractions. There are no restriction rules for the Darwin River Dam. Modelling

commences on the 1 September 2007 and streamflow metrics are produced by modelling the 77-year historical

climate sequence between 1 September 1930 and 31 August 2007. This scenario is used as a baseline for

comparison with all other scenarios.


Current levels of development such as public storages and demands are not considered when determining


or farm dam development because the impact of these factors on catchment yields in this region is considered

to be negligible. Hence this scenario used the same inflow sequence as Scenario A.


This scenario assumes without-development conditions (as per Scenario AN) and uses seven consecutive 11-

year climate sequences between 1 September 1996 and 31 August 2007 to generate 77-year time series for

runoff and climate.


Scenarios CNwet, CNmid and CNdry represent a range of future climate conditions assuming without-

development conditions (as per Scenario AN).

• Scenario B – recent climate and current development

This scenario incorporates the effects of current land use and constant demand pattern as per Scenario A and

uses seven consecutive 11-year climate sequences between 1 September 1996 and 31 August 2007 to

generate 77-year time series for runoff and climate.

• Scenario C – future climate and current development

Scenarios Cwet, Cmid and Cdry represent a range of future climate conditions assuming current levels of

development (i.e. as per Scenario A). Rainfall-runoff results from the Van Diemen region chapter of the Timor

Sea Drainage Division report (CSIRO, 2009) were used to scale the inflows to the Darwin River Dam.

• Scenario D – future climate and 2030 development

Scenarios Dwet, Dmid and Ddry represent a range of future climate conditions for a 2030 development scenario.

Under Scenario D the daily demand pattern used under Scenario A was increased proportionally so that the

total annual demand was equal to 50,000 ML. Projections of commercial forestry and farm dams for 2030 are

negligible and hence no adjustments were made to the Scenario C runoff time series.

The Northern Australia Sustainable Yields Project scenario simulations use comparable but different initial conditions and

a different simulation period than what was used by SKM (2005). Results from these scenarios are not intended to be

directly comparable with the SKM (2005) simulations.

The changes in inflows between scenarios reported in this chapter differ from the changes in runoff reported in the Van

Diemen rainfall-runoff chapter in the Timor Sea Drainage Division report. These differences are due to differences in the

methods by which the GCMs were ranked and differences in areas that are considered to contribute runoff to the surface

water model. In the Van Diemen rainfall-runoff chapter in the Timor Sea Drainage Division report the entire region is


considered while a subset of this area is considered here. The scenarios presented in this project may not eventuate but

they encompass consequences that might arise if no management changes are made. Consequently results from this

assessment are designed to highlight pressure points in the system, both now and in the future. This assessment does

not elaborate on what management actions might be taken to address any of these pressure points. Where management

changes to mitigate the effects of climate change have recently been implemented, the impacts of the changes predicted

in this section may be an overestimate.


The Darwin River Dam was commissioned in 1972 and supplies approximately 90 percent of Darwin’s water supply. The

Darwin River Dam model consists of a single node to represent the dam (Table 6) and has one diversion (Table 7). Table

6 presents a summary of average annual values for the Darwin River Dam under Scenario A. Average annual releases

are the sum of the controlled releases and extractions from the dam. The degree of regulation metric is defined in this

project to be the sum of the net evaporation and controlled releases from the dam divided by the total inflows. Controlled

releases include water for irrigation demands, for hydropower generation and for environmental water provisions, but

exclude spills. The degree of regulation for the Darwin River Dam is 0.64, which is high relative to other storages in

northern Australia.

Table 6. Storages in the Darwin River Dam system model

Active storage

Average annual Inflow


Average annual

diversion



GL GL/y Major storages Darwin River Dam 204.8 136.0 49.1 49.0 37.8 0.64 Region total 204.8 136.0 49.1 49.0 37.8 0.64

Table 7. Modelled water use configuration in the Darwin River Dam system model

Water users Number of nodes Licence or long term diversions

Model notes

GL/y

Town Water Supply 1 49.1 Daily demand pattern

Sub-total 1 49.1

Model setup

A summary of the model details is provided in Table 8. The Darwin River Dam spillway is currently being upgraded and

raised by 1.3 m, which increases the dam full supply from to 265 GL to 324.8 GL. All scenarios have been considered

with this new dam configuration.


Table 8. Darwin River Dam system model setup information

Model setup information Start date End date

Darwin River Dam Excel Spreadsheet 1/09/2007 31/08/2084

Connection

Baseline models

Connection

Modifications

Data Data extension from 2003 to 2007

Inflows No adjustment

Initial storage volume 281.8 GL Modelled level from the 1 August 2007

Storage Dam volume increased from 274.4 to 324.8 GL


The mass balance table (Table 9) shows the net fluxes for the Darwin River Dam system. The fluxes under Scenario A

are displayed in GL/year and all of the other scenarios are presented as a percentage change from Scenario A.

Diversions are for the town water supply of Darwin. The end-of-system flows represent the releases and spills made from

the dam.

The large increase in inflows under Scenario B is due to the statistically significant increase in rainfall under Scenario B

relative to Scenario A.

Net evaporation from the Darwin River Dam is a large proportion of the average annual inflow to the lake (approximately

28 percent) and controlled releases (approximately 77 percent).

Table 9. River system model mean annual water balance under Scenario A and under scenarios B, C and D relative to Scenario A

A B Cwet Cmid Cdry Dwet Dmid Ddry

GL/y

Storage volume

Change over period 0.02 0.02 0.00 0.04 -0.04 -0.01 0.03 -0.04


Inflows

Subcatchments

Gauged 136.0 62% 32% 1% -21% 32% 1% -21%

Sub-total 136.0 62% 32% 1% -21% 32% 1% -21%

Diversions

Town Water Supply

High Security 49.0 0% 0% 0% -5% 2% 2% -4%

Sub-total 49.0 0% 0% 0% -5% 2% 2% -4%

Outflows

End of system flow 49.1 192% 100% 0% -64% 98% -1% -65%

Sub-total 49.1 192% 100% 0% -64% 98% -1% -65%

Net evaporation

Darwin River Dam 37.8 -26% -16% 5% 14% -16% 4% 14%

Sub-total 37.8 -26% -16% 5% 14% -16% 4% 14%

River system reach water balance

There were no reaches in this river system model. It consists of a single node.


Scaling results

Catchment identifier corresponds to the SRN number. Average monthly scaling factors for streamflow, rainfall and

evaporation under scenarios B and C are listed in Table 10 to Table 21.

Table 10. Darwin River Dam – Streamflow scaling factors for Scenario B

Catchment J F M A M J J A S O N D Annual Monthly annual

60012 2.055 1.258 1.538 2.190 1.315 1.392 1.461 1.556 1.646 1.564 1.481 2.048 1.624 1.677

Table 11. Darwin River Dam – Rainfall Scaling factors for Scenario B


60012 1.184 1.090 1.185 1.390 0.612 0.261 0.085 1.387 0.548 1.379 1.096 1.346 1.189 1.190

Table 12. Darwin River Dam – Evaporation scaling factors for Scenario B


60012 1.001 1.015 0.995 1.016 1.024 1.001 1.020 1.009 1.020 1.012 1.014 0.988 1.009 1.010

Table 13. Darwin River Dam – Streamflow scaling factors for Scenario Cwet


60012 1.552 1.387 1.092 1.028 1.067 1.121 1.162 1.214 1.326 1.979 4.123 2.162 1.320 1.448

Table 14. Darwin River Dam – Streamflow scaling factors for Scenario Cmid


60012 0.968 0.998 1.063 1.052 1.021 1.018 1.016 1.017 1.013 0.941 0.788 0.880 1.015 0.998

Table 15. Darwin River Dam – Streamflow Scaling factors for Scenario Cdry


60012 0.792 0.846 0.776 0.768 0.829 0.851 0.831 0.801 0.768 0.641 0.423 0.605 0.789 0.770

Table 16. Darwin River Dam – Rainfall scaling factors for Scenario Cwet


60012 1.090 1.087 0.962 0.962 0.963 0.992 0.992 0.992 1.586 1.586 1.586 1.088 1.127 1.133

Table 17. Darwin River Dam – Rainfall scaling factors for Scenario Cmid


60012 1.016 1.020 1.029 1.017 1.016 1.183 1.183 1.183 0.936 0.920 0.914 1.031 1.008 1.007

Table 18. Darwin River Dam – Rainfall scaling factors for Scenario Cdry


60012 0.976 0.972 0.900 0.895 0.891 0.822 0.822 0.822 0.570 0.560 0.555 0.963 0.893 0.888


Table 19. Darwin River Dam – Evaporation scaling factors for Scenario Cwet


60012 0.978 0.978 1.019 1.019 1.019 1.024 1.024 1.024 1.022 1.022 1.022 0.978 1.011 1.012

Table 20. Darwin River Dam – Evaporation scaling factors for Scenario Cmid


60012 1.021 1.021 1.021 1.021 1.021 1.033 1.033 1.033 1.023 1.023 1.023 1.021 1.024 1.025

Table 21. Darwin River Dam – Evaporation scaling factors for Scenario Cdry


60012 1.064 1.064 1.069 1.069 1.069 1.036 1.036 1.036 1.039 1.039 1.039 1.064 1.052 1.051


3.4 Leichhardt

Model overview

The Leichhardt catchment was modelled using the IQQM program (version 6.42.2). The model was set up by the

Department of Environment and Resource Management to support the Queensland Water Resource Planning Process.

Results from this model for the period from January 1890 to June 2003 were used to establish the water sharing rules in

the draft Gulf Resource Operations Plan (DNRW, 2008). The level of development represented by the model is based on

the full use of existing entitlements. It should be noted that the results presented in DERM reports (Water Assessment

Group, 2006a) may differ from numbers published in this report due to the different modelling period and different initial

conditions.

As part of the Northern Australia Sustainable Yields Project, input data for the model were extended so that they covered

the period 1 January 1890 to 30 June 2008. The results for this project are reported for 77-year sequences. In this

project the river system modelling for the Leichhardt catchment consist of ten scenarios:

• Scenario A – historical climate sequence and full use of existing entitlements

This scenario assumes a full use of existing entitlements. Full use of existing entitlements refers to the total

entitlements within a plan area including existing water authorisations and unallocated reserves. This refers to

the water accounted for in the draft Gulf Resource Operations Plan, but the licences are interim or not allocated

as yet. The period of analysis commences on 1 September 2007 and streamflow metrics are produced by

modelling the 77-year historical climate sequence between 1 September 2007 and 31 August 2084. This

scenario is used as a baseline for comparison with all other scenarios.


Current levels of development such as public storages and demand nodes are removed from the model to

represent without-development conditions. Inflows were not modified for groundwater extraction, major land use

change or farm dam development because the impact of these factors on catchment yield are currently

considered to be negligible. This scenario uses the historical flow and climate inputs used for Scenario A.





considered to be negligible. This scenario incorporates the effects of current land use and uses seven

consecutive climate sequences between 1 September 1996 and 31 August 2007 to generate a 77-year climate

sequence representative of the ‘recent climate’.





considered to be negligible. Scenarios CNwet, CNmid and CNdry represent a range of future climate conditions

that are derived by adjusting the historical climate and flow inputs used in Scenario A.

• Scenario B – recent climate and full use of existing entitlements

This scenario incorporates the effects of current land use and uses seven consecutive climate sequences

between 1 September 1996 and 31 August 2007 to generate a 77-year climate sequence representative of the

‘recent climate’.

• Scenario C – future climate and full use of existing entitlements

Scenarios Cwet, Cmid and Cdry represent a range of future climate conditions that are derived by adjusting the

historical climate and flow inputs used in Scenario A. The level of development for Scenario C assumes the full

use of existing entitlements, i.e. the same as for Scenario A.

No future development information were available for the Leichhardt River catchment. Hence Scenario D was not

analysed.


The changes in inflows between scenarios reported in this chapter differ from the changes in runoff reported in the

Flinders-Leichhardt rainfall-runoff chapter of the Gulf of Carpentaria division report. These differences are due to

difference in the methods by which the GCMs were ranked and difference in areas that are considered to contribute

runoff to the surface water model. In the Flinders-Leichhardt rainfall-runoff chapter of the Gulf of Carpentaria division

report the entire region is considered while a subset of this area is considered here. The scenarios presented in this

project may not eventuate but they encompass consequences that might arise if no management changes were made.

Consequently results from this assessment are designed to highlight pressure points in the system, both now and in the

future. This assessment does not elaborate on what management actions might be taken to address any of these

pressure points. Where management changes to mitigate the effects of climate change have recently been implemented,

the impacts of the changes predicted in this section may be an overestimate.


The Leichhardt region is described by the Leichhardt IQQM systems model (Water Assessment Group, 2006a). The

model extends from the headwaters of the river basin and includes Rifle Creek south of Mount Isa, to the mouth of the

Leichhardt River on the Gulf of Carpentaria north-east of Burketown. The Floraville gauge (913007) is the most

downstream flow monitoring station in the system (Figure 13). The tributaries of the Leichhardt system include Alexandra

River, Paroo Creek, Gunpowder Creek, Mistake Creek, Gorge Creek, Rifle Creek, Fiery Creek and Doughboy Creek.

The system is represented in the model by 42 river sections and 122 nodes (Appendix 1). Thirty-one of these nodes are

water accounting nodes which are used for simulating water-harvesting rules in the lower section of the basin. There are

five large storages and four smaller instream storages in the model. There are no passing flow requirements for the

major storages. Details of the major storages in the Leichhardt catchment are provided in Table 22. The degree of

regulation metric in Table 22 is the sum of the net evaporation and controlled released from the dam divided by the total

inflows. Controlled releases exclude spillage. Storages with radial gates and without spillways are not reported in this

table. The degree of regulation of Rifle Creek Dam and Lake Moondarra are 0.68 and 0.71 respectively. The remaining

three major storages in the Leichhardt catchment have a degree of regulation ranging from 0.3 to 0.38.

This model was developed as a planning tool and consequently has been set up assuming full use of existing

entitlements. Water use nodes in the model are categorised into different uses in Table 23. Diversions are modelled

from:

1. 13 nodes representing high security supply

2. 3 nodes representing irrigation supply from private storages

3. 7 nodes representing high flow (water harvesting) diversions (2 divert water into tributaries, therefore not

included in Table 23)

4. 2 nodes representing unregulated diversions.


Figure 13. Schematic of the approximate location of gauging stations, main demand nodes and storages for the Flinders river system

model (green lines) and Leichhardt river system model (pink lines)

Table 22. Major storages in the Leichhardt river system model

Major storages Active storage Average annual inflow




GL GL/y

Julius 100.1 222.9 48.0 19.6 0.30

Lake Moondarra 103.2 61.3 22.5 20.8 0.71

Waggaboonya 14.0 18.2 2.2 3.2 0.30

Lake Mary Kathleen

12.2 34.3 1.0 12.2 0.38

Rifle Creek 9.5 5.4 1.5 2.2 0.68

Total 238.98 342.10 75.18 57.99 0.39

In Table 23 and the sections that follow, ‘volumetric limit’ is defined as being the maximum volume of water that can be

extracted from a river system within this region under the draft Gulf Resource Operations Plan. Unsupplemented water is

defined as surface water that is not sourced from a water storage that is able to regulate or control supply to users.


Table 23. Modelled water use configuration in the Leichhardt river system model


Volumetric limit

Model notes

GL/y

Agriculture

General Security 4 15.7 Fixed Demand

Unsupplemented 5 26.0

Mining

High Security 5 31.5 Fixed Demand

Unsupplemented 2 4.0 Fixed Demand

Town Water Supply


Other Demands


Total 23 111.6

Model setup

The original Leichhardt river model and associated IQQM V6.42.2 executable code were obtained from DERM. The time

series rainfall, evaporation and flow inputs to this model for the historical climate time series were set to cover the

reporting period 1 September 2007 to 31 August 2084. The model was run for the reporting period and validated against

the original model run results for the same period. Model setup information for the Leichhardt river system model is

summarised in Table 24.

The initial state of storages can influence the results obtained so the same initial storage levels were used for all

scenarios. In this project all scenarios are reported for a common 77-year sequence commencing on 1 September 2007.

However the demand simulated by an IQQM model for month n is dependent upon the simulation results for month n-1.

For this reason the initial conditions (i.e. storage levels) are set to the levels simulated on the 1 August 2007 for all

scenarios. The models are then run for 77 years and one month.

A without-development version of the Leichhardt model was created by inactivating all instream storages, all demand

and diversion nodes.

Table 24. Leichhardt river system model setup information


Leichhardt IQQM 6.42.2 01/01/1890 30/06/2008

Connection

Baseline models

Warm up period 1/08/2007 31/08/2007

Leichhardt IQQM 6.42.2 1/09/2007 31/08/2084

Connection

Modifications

Data Data extended by DERM

Inflows

Initial storage volumes

Julius 79.8 GL

Lake Moondarra 43.6 GL

Waggaboonya 8.8 GL

Lake Mary Kathleen 4.4 GL

Rifle Creek 5.7 GL

Modelled level for 1 August 2007



The mass balance table (Table 25) shows volumetric components under Scenario A as GL/year, with all other scenarios



The directly gauged inflows represent the inflows into the model that are based on data from a river gauge. The indirectly

gauged inflows include inflows that are derived to achieve a mass balance between mainstream gauges. Diversions are

listed based on the different water products in the region. End-of-system flows are shown for the Leichhardt River at

modelled end-of-system which includes inflows from Alexandra River and Lagoon Creek that join below gauge 913007.

Mass balance tables for the reaches in the model are reported in the following section. The mass balance of each of

these river reaches and the overall mass balance were checked by taking the difference between total inflows and

outflows of the system. In all cases the mass balance error was zero. Unattributed fluxes in Table 25 are the modelled

river losses. River losses are estimated from loss relationships that are determined during calibration of the IQQM model

such that flow is conserved between upstream and downstream gauging stations.

Results in Table 25 show that under scenarios Cwet and Cdry, inflows in the Leichhardt catchment increase by

27 percent and decrease by 23 percent respectively. End-of-system flow increases by 29 percent and decrease by 25

percent under scenarios Cwet and Cdry respectively. However, the impact of climate change on diversions is small

(<5 percent) as demands in the region are low compared to the total inflows.

There is a larger increase in inflows under Scenario B for the Leichhardt (52 percent) than the Flinders (6 percent). This

difference can be explained by the spatial distribution of the increase in rainfall under Scenario B.


Table 25. Leichhardt river system model mean annual water balance under Scenario A and under scenarios B and C relative to

Scenario A

A B Cwet Cmid Cdry

GL/y

Storage volume

Change over period 0.0 0.7 0.5 0.3 -0.5


Inflows

Subcatchments

Gauged 233.0 70% 35% 19% -22%

Ungauged 1807.7 50% 25% 19% -24%

Sub-total 2040.7 52% 27% 19% -23%

Diversions

Agriculture

General Security 7.8 -2% 0% 0% -1%

Unsupplemented 23.6 5% 2% 2% -4%

Mining

High Security 29.4 5% 4% 2% -6%


Town Water Supply

High Security 32.3 5% 3% 2% -5%

Other Uses

High Security 13.9 2% 1% 1% -2%

Sub-total 110.8 4% 3% 2% -4%

Outflows

End-of-system flow 1784.6 57% 29% 21% -25%

Sub-total 1784.6 57% 29% 21% -25%

Net evaporation

Major storages 71.6 18% 14% 9% -10%

Other Storages 1.2 5% 0% -1% -4%

Sub-total 72.8 17% 13% 9% -10%

Unattributed fluxes

72.4 38% 18% 10% -16%



Annual water balances for individual reaches in the Leichhardt river system model are summarised in Table 26 to Table

31.

Table 26. Leichardt water balance – gauge 913999

913999 A B Cwet Cmid Cdry

GL/y

Storage volume

Change over period 0.0 0.0 0.0 0.0 0.0


Inflows

Subcatchments

Gauged 1225.0 68% 32% 21% -25%

Ungauged 580.6 32% 21% 19% -25%

Sub-total 1805.6 56% 29% 20% -25%

Diversions

Agriculture

General Security 1.1 -13% 1% -1% -5%


Sub-total 7.4 1% 0% 1% -4%

Outflows

End of system flow 1784.6 57% 29% 21% -25%

Sub-total 1784.6 57% 29% 21% -25%

Net evaporation

Major Storages 13.6 -3% 2% 1% -9%

Other Storages

Sub-total 13.6 -3% 2% 1% -9%

Unattributed fluxes

0.0 50% -3% 83% -140%


Table 27. Leichardt River water balance – gauge 913003


GL/y

Storage volume



Inflows

Subcatchments

Gauged 112.0 82% 37% 19% -21%

Ungauged 100.8 56% 29% 18% -22%

Sub-total 212.8 70% 33% 18% -22%

Diversions

Mining

High Security 2.0 1% 1% 0% -3%


Town Water Supply


Other Uses

High Security 0.0 0% 0% 0% 0%

Sub-total 4.0 2% 1% 1% -3%

Outflows


Sub-total 198.6 74% 35% 19% -23%

Net evaporation

Major Storages 3.2 10% 12% 7% -7%

Other Storages

Sub-total 3.2 10% 12% 7% -7%

Unattributed fluxes

6.9 13% 8% 3% -9%




Inflows

Subcatchments

Gauged 532.5 99% 44% 24% -26%

Ungauged 759.8 41% 22% 18% -23%

Sub-total 1292.4 65% 31% 20% -24%

Diversions

Agriculture

General Security 6.7 0% 0% 0% 0%


Sub-total 24.0 4% 2% 2% -4%

Outflows


Sub-total 1225.0 68% 32% 21% -25%

Net evaporation

Major Storages

Other Storages 1.2 5% 0% -1% -4%

Sub-total 1.2 5% 0% -1% -4%

Unattributed fluxes

42.1 21% 10% 6% -13%





Inflows

Subcatchments

Gauged 155.3 166% 66% 36% -34%

Ungauged 98.8 82% 37% 17% -21%

Sub-total 254.1 134% 54% 29% -29%

Diversions

Mining



Sub-total 2.3 4% 3% 1% -5%

Outflows


Sub-total 239.0 139% 56% 30% -30%

Net evaporation

Major Storages

Other Storages 0.0 3% 2% 3% 8%

Sub-total 0.0 3% 2% 3% 8%

Unattributed fluxes

12.8 62% 28% 14% -22%



GL/y

Storage volume



Inflows

Subcatchments

Gauged 158.2 122% 50% 28% -26%

Ungauged 74.8 99% 38% 21% -21%

Sub-total 233.0 115% 46% 26% -24%

Diversions

Mining

High Security 14.8 0% 0% 0% -1%

Unsupplemented

Town Water Supply

High Security 21.4 0% 0% 0% -1%

Other Uses

High Security 11.8 0% 0% 0% -1%

Sub-total 48.0 0% 0% 0% -1%

Outflows


Sub-total 155.3 166% 66% 36% -34%

Net evaporation

Major Storages 19.6 -3% 3% 5% -1%

Other Storages

Sub-total 19.6 -3% 3% 5% -1%

Unattributed fluxes

10.1 95% 44% 25% -26%




GL/y

Storage volume



Inflows

Subcatchments

Gauged 12.3 104% 42% 24% -24%

Ungauged 193.0 97% 41% 24% -23%

Sub-total 205.3 97% 41% 24% -23%

Diversions

Agriculture

General Security 0.0 10% 6% 2% -10%


Mining

High Security 12.2 12% 9% 6% -12%

Unsupplemented

Town Water Supply

High Security 10.7 14% 10% 6% -13%

Other Uses


Sub-total 25.1 13% 9% 6% -12%

Outflows


Sub-total 144.5 126% 51% 29% -26%

Net evaporation

Major Storages 35.2 38% 24% 15% -15%

Other Storages 0.0 12% 8% 6% -7%

Sub-total 35.2 38% 24% 15% -15%

Unattributed fluxes

0.5 10% 7% 4% -7%


Scaling results

The river basin boundaries and the subdivision of the river basin into subcatchments for modelling purposes are shown

in Figure 14. Donor to target catchment relationships for the Leichhardt catchment are also illustrated in Figure 14. See

Petheram et al. (2009) for more details. Average monthly scaling factors for streamflow, rainfall and evaporation under

scenarios B and C are listen in Table 32 to Table 43. Catchment number in the scaling factor tables refers to the SRN

number used for the rainfall-runoff modelling.

Figure 14. Donor to target catchment mapping relationships. Rainfall-runoff modelling gauging stations (red triangles) and streamflow

modelling gauging stations (blue triangles). Donor to target catchment parameter mapping relationships are shown by the black arrows.

Inset shows area of calibration rainfall-runoff gauging stations.


Table 32. Leichardt River – Streamflow scaling factors for Scenario B


8101 2.067 0.878 3.663 1.974 0.168 1.694 0.158 0.000 0.091 2.536 4.245 3.496 2.259 2.145

8004 2.223 0.800 3.104 2.317 0.190 1.871 0.231 0.002 0.332 2.042 4.932 3.336 2.070 2.135

8251 2.292 0.754 2.711 2.508 0.261 1.869 0.191 0.046 0.000 2.683 4.983 3.399 1.944 2.037

8009 2.107 0.820 2.386 2.735 0.406 1.025 0.144 0.005 2.445 0.583 4.679 4.079 1.842 1.997

8011 2.290 0.882 2.480 3.223 0.319 1.224 0.252 0.001 2.506 0.556 2.683 4.691 2.043 2.110

8016 1.906 0.808 2.246 3.596 0.367 0.926 0.224 0.001 1.325 0.120 2.564 4.528 1.838 1.873

8019 2.055 1.054 1.858 2.763 0.651 0.340 0.249 0.003 3.238 0.484 3.740 4.231 1.834 1.893

8153 1.820 0.909 1.835 3.193 0.583 0.193 0.042 0.001 2.453 0.174 1.744 4.355 1.741 1.770

8023 1.517 0.798 1.819 3.480 0.486 0.350 0.077 0.002 0.300 0.094 1.581 4.109 1.572 1.610

8026 1.065 0.808 1.256 2.330 0.263 0.062 0.016 0.147 0.025 0.274 0.385 5.253 1.314 1.265

8250 1.089 0.731 1.893 3.360 0.400 0.355 0.068 0.307 0.031 0.005 2.137 3.887 1.400 1.410

8001 2.262 0.984 2.837 2.223 0.207 1.619 0.175 0.001 0.926 1.236 6.332 3.158 2.047 2.091

8261 2.166 0.689 2.975 2.637 0.271 1.929 0.229 0.001 0.000 3.143 3.426 3.642 1.987 2.030

8181 1.962 0.712 3.670 1.834 0.179 1.730 0.170 0.000 0.025 2.516 3.248 3.644 2.198 2.079

8006 2.111 0.726 2.719 2.755 0.156 1.711 0.160 0.000 0.489 2.413 2.792 4.013 1.914 1.985

8020 1.453 0.860 1.416 2.967 0.444 0.053 0.006 0.000 0.624 0.347 0.974 4.263 1.479 1.519

8028 0.985 0.861 1.677 3.458 0.235 0.103 0.029 0.235 0.044 0.072 0.399 3.785 1.378 1.338

8231 0.820 0.534 1.699 4.050 0.340 0.164 0.031 0.283 0.514 0.000 0.282 2.587 1.150 1.124

8108 1.375 0.770 1.946 3.948 1.023 0.841 0.161 1.061 1.491 0.006 5.792 3.660 1.636 1.609

Table 33. Leichardt River – Rainfall scaling factors for Scenario B


8001 1.524 1.158 1.206 1.502 0.201 1.356 0.247 0.698 0.998 1.186 1.611 1.649 1.310 1.325

8009 1.508 1.052 1.163 1.723 0.123 1.213 0.079 0.522 1.111 1.364 1.489 1.679 1.291 1.303

8020 1.385 1.069 0.941 2.046 0.117 1.111 0.143 0.324 0.866 1.108 1.268 1.532 1.204 1.213

8019 1.526 1.129 0.994 1.913 0.124 1.150 0.074 0.458 1.156 1.360 1.422 1.640 1.292 1.300

Table 34. Leichardt River – Evaporation scaling factors for Scenario B


8001 0.961 1.008 1.010 1.000 0.994 0.980 0.998 0.983 1.016 0.997 0.978 0.966 0.990 0.990

8009 0.963 1.013 1.013 1.005 1.002 0.988 1.006 0.990 1.022 1.001 0.981 0.968 0.994 0.994

8020 0.967 1.015 1.018 1.012 1.015 0.996 1.018 1.001 1.029 1.002 0.984 0.967 0.999 1.000

8019 0.965 1.012 1.016 1.010 1.009 0.992 1.013 0.997 1.028 1.001 0.982 0.967 0.997 0.997


Table 35. Leichardt River – Streamflow scaling factors for Scenario Cwet


8101 1.208 1.234 1.610 1.969 1.929 1.252 1.200 1.060 1.018 1.059 0.995 1.233 1.404 1.331

8004 1.205 1.217 1.648 2.021 1.878 1.242 1.182 1.059 1.026 1.031 0.995 1.231 1.396 1.336

8251 1.211 1.205 1.684 1.993 1.930 1.230 1.234 1.106 1.038 1.040 0.999 1.256 1.385 1.347

8009 1.195 1.208 1.693 2.068 1.885 1.288 1.263 1.144 1.043 1.015 0.997 1.224 1.364 1.340

8011 1.205 1.207 1.614 1.832 2.018 1.236 1.157 1.171 1.068 1.035 1.011 1.199 1.361 1.312

8016 1.203 1.193 1.576 1.802 1.980 1.223 1.153 1.139 1.069 1.028 1.011 1.189 1.348 1.311

8019 1.187 1.216 1.711 1.962 1.910 1.203 1.045 0.975 0.979 0.976 0.943 1.199 1.359 1.319

8153 1.175 1.200 1.667 1.906 1.882 1.243 1.095 1.053 1.041 1.021 1.005 1.171 1.348 1.304

8023 1.169 1.191 1.605 1.855 1.862 1.234 1.076 1.005 1.035 1.025 1.008 1.188 1.337 1.295

8026 0.997 0.993 1.653 2.021 2.016 1.232 0.986 1.154 0.489 0.621 0.688 0.983 1.187 1.145

8250 1.113 1.132 1.612 1.864 2.112 1.344 1.063 1.201 0.947 0.941 0.934 1.134 1.302 1.260

8001 1.214 1.226 1.681 1.953 1.897 1.230 1.219 1.107 1.033 1.036 0.993 1.241 1.396 1.343

8261 1.202 1.203 1.647 2.087 1.933 1.257 1.206 1.318 1.026 1.046 1.001 1.247 1.391 1.339

8181 1.196 1.219 1.586 2.056 1.913 1.255 1.201 1.050 1.018 1.062 0.996 1.233 1.396 1.325

8006 1.209 1.205 1.646 1.896 1.990 1.230 1.180 1.082 1.068 1.046 1.013 1.245 1.379 1.336

8020 1.058 1.076 1.636 1.945 1.849 1.212 1.046 0.957 0.886 0.901 0.874 1.051 1.246 1.208

8028 0.951 0.947 1.556 1.824 2.015 1.270 1.021 1.205 0.596 0.669 0.715 0.930 1.131 1.114

8231 0.940 0.941 1.518 1.784 2.071 1.342 0.971 1.150 1.219 0.684 0.695 0.914 1.078 1.101

8108 0.945 0.948 1.531 1.565 2.025 1.685 0.983 1.281 1.458 0.334 0.537 0.919 1.104 1.098

Table 36. Leichardt River – Streamflow scaling factors for Scenario Cmid


8101 1.077 1.064 1.439 1.597 1.685 1.180 1.141 1.070 0.745 0.460 0.719 1.071 1.233 1.158

8004 1.069 1.061 1.447 1.602 1.644 1.170 1.133 1.061 0.751 0.510 0.751 1.062 1.218 1.162

8251 1.085 1.062 1.458 1.589 1.656 1.150 1.146 1.016 0.579 0.547 0.758 1.053 1.208 1.168

8009 1.082 1.054 1.467 1.675 1.649 1.188 1.160 1.107 0.695 0.720 0.730 1.024 1.191 1.164

8011 1.069 1.050 1.427 1.525 1.728 1.142 1.095 1.160 0.685 0.713 0.733 1.036 1.192 1.142

8016 1.145 1.110 1.229 1.251 1.383 1.196 1.164 1.615 0.631 0.693 0.664 1.130 1.163 1.146

8019 1.181 1.133 1.237 1.296 1.354 1.210 1.194 1.452 0.665 0.719 0.658 1.191 1.183 1.166

8153 1.234 1.175 1.117 1.089 1.151 1.229 1.268 1.944 0.610 0.692 0.631 1.268 1.175 1.186

8023 1.216 1.173 1.116 1.077 1.152 1.237 1.230 1.291 0.585 0.725 0.613 1.260 1.167 1.167

8026 1.269 1.176 1.146 1.111 1.185 1.238 1.207 1.196 0.496 0.541 0.616 1.302 1.202 1.204

8250 1.237 1.187 1.090 1.035 1.110 1.198 1.184 1.184 0.606 0.655 0.568 1.270 1.170 1.171

8001 1.077 1.057 1.460 1.594 1.666 1.166 1.150 1.095 0.676 0.525 0.729 1.068 1.212 1.159

8261 1.070 1.064 1.445 1.647 1.657 1.165 1.130 1.242 0.656 0.566 0.748 1.041 1.215 1.163

8181 1.065 1.058 1.434 1.697 1.669 1.188 1.142 1.062 0.767 0.490 0.693 1.054 1.234 1.159

8006 1.072 1.059 1.447 1.574 1.692 1.137 1.112 1.080 0.709 0.671 0.759 1.026 1.205 1.161

8020 1.238 1.177 1.122 1.097 1.159 1.235 1.245 1.179 0.535 0.706 0.648 1.273 1.181 1.190

8028 1.242 1.153 1.124 1.077 1.174 1.240 1.220 1.203 0.571 0.578 0.626 1.348 1.185 1.178

8231 1.308 1.231 1.017 0.913 0.938 1.141 1.190 1.143 1.060 0.666 0.696 1.425 1.227 1.200

8108 1.236 1.136 1.036 0.989 0.991 1.397 1.525 1.332 1.144 0.720 0.684 1.373 1.164 1.155


Table 37. Leichardt River – Streamflow scaling factors for Scenario Cdry


8101 1.208 1.234 1.610 1.969 1.929 1.252 1.200 1.060 1.018 1.059 0.995 1.233 1.404 1.331

8004 1.205 1.217 1.648 2.021 1.878 1.242 1.182 1.059 1.026 1.031 0.995 1.231 1.396 1.336

8251 1.211 1.205 1.684 1.993 1.930 1.230 1.234 1.106 1.038 1.040 0.999 1.256 1.385 1.347

8009 1.195 1.208 1.693 2.068 1.885 1.288 1.263 1.144 1.043 1.015 0.997 1.224 1.364 1.340

8011 1.205 1.207 1.614 1.832 2.018 1.236 1.157 1.171 1.068 1.035 1.011 1.199 1.361 1.312

8016 1.203 1.193 1.576 1.802 1.980 1.223 1.153 1.139 1.069 1.028 1.011 1.189 1.348 1.311

8019 1.187 1.216 1.711 1.962 1.910 1.203 1.045 0.975 0.979 0.976 0.943 1.199 1.359 1.319

8153 1.175 1.200 1.667 1.906 1.882 1.243 1.095 1.053 1.041 1.021 1.005 1.171 1.348 1.304

8023 1.169 1.191 1.605 1.855 1.862 1.234 1.076 1.005 1.035 1.025 1.008 1.188 1.337 1.295

8026 0.997 0.993 1.653 2.021 2.016 1.232 0.986 1.154 0.489 0.621 0.688 0.983 1.187 1.145

8250 1.113 1.132 1.612 1.864 2.112 1.344 1.063 1.201 0.947 0.941 0.934 1.134 1.302 1.260

8001 1.214 1.226 1.681 1.953 1.897 1.230 1.219 1.107 1.033 1.036 0.993 1.241 1.396 1.343

8261 1.202 1.203 1.647 2.087 1.933 1.257 1.206 1.318 1.026 1.046 1.001 1.247 1.391 1.339

8181 1.196 1.219 1.586 2.056 1.913 1.255 1.201 1.050 1.018 1.062 0.996 1.233 1.396 1.325

8006 1.209 1.205 1.646 1.896 1.990 1.230 1.180 1.082 1.068 1.046 1.013 1.245 1.379 1.336

8020 1.058 1.076 1.636 1.945 1.849 1.212 1.046 0.957 0.886 0.901 0.874 1.051 1.246 1.208

8028 0.951 0.947 1.556 1.824 2.015 1.270 1.021 1.205 0.596 0.669 0.715 0.930 1.131 1.114

8231 0.940 0.941 1.518 1.784 2.071 1.342 0.971 1.150 1.219 0.684 0.695 0.914 1.078 1.101

8108 0.945 0.948 1.531 1.565 2.025 1.685 0.983 1.281 1.458 0.334 0.537 0.919 1.104 1.098

Table 38. Leichardt River – Rainfall scaling factors for Scenario Cwet


8001 1.102 1.103 1.307 1.324 1.307 1.011 1.013 1.015 1.007 1.006 1.006 1.110 1.133 1.129

8009 1.102 1.100 1.309 1.318 1.307 1.011 1.013 1.014 1.008 1.007 1.005 1.115 1.133 1.132

8020 1.061 1.058 1.311 1.332 1.310 0.995 0.997 0.999 0.983 0.980 0.980 1.070 1.103 1.102

8019 1.107 1.103 1.309 1.317 1.304 0.992 0.992 0.994 0.998 0.996 0.995 1.117 1.133 1.130

Table 39. Leichardt River – Rainfall scaling factors for Scenario Cmid


8001 1.010 1.011 1.198 1.189 1.198 1.014 1.010 1.007 0.897 0.902 0.897 1.002 1.037 1.033

8009 1.012 1.011 1.197 1.193 1.199 1.013 1.010 1.008 0.910 0.903 0.894 0.996 1.036 1.035

8020 1.013 1.012 1.030 1.019 1.032 1.079 1.079 1.079 0.901 0.899 0.896 0.988 1.000 1.000

8019 1.013 1.011 1.085 1.085 1.091 1.055 1.054 1.053 0.906 0.901 0.894 0.991 1.012 1.011

Table 40. Leichardt River – Rainfall scaling factors for Scenario Cdry


8001 0.976 0.975 0.869 0.873 0.869 0.939 0.951 0.962 0.822 0.824 0.819 0.983 0.931 0.933

8009 0.974 0.974 0.870 0.870 0.868 0.940 0.951 0.959 0.835 0.826 0.815 0.987 0.932 0.934

8020 0.976 0.975 0.871 0.869 0.865 0.942 0.948 0.960 0.835 0.822 0.819 0.983 0.935 0.936

8019 0.975 0.975 0.871 0.870 0.865 0.943 0.949 0.955 0.837 0.825 0.816 0.983 0.933 0.934

Table 41. Leichardt River – Evaporation scaling factors for Scenario Cwet


8001 1.021 1.021 1.018 1.018 1.018 1.035 1.035 1.035 1.028 1.028 1.028 1.021 1.025 1.025

8009 1.021 1.021 1.017 1.017 1.017 1.035 1.035 1.035 1.028 1.028 1.028 1.021 1.024 1.025

8020 1.032 1.032 1.018 1.018 1.018 1.036 1.036 1.036 1.029 1.029 1.029 1.032 1.028 1.029

8019 1.020 1.020 1.017 1.017 1.017 1.035 1.035 1.035 1.030 1.030 1.030 1.020 1.025 1.025


Table 42. Leichardt River – Evaporation scaling factors for Scenario Cmid


8001 1.021 1.021 1.033 1.033 1.033 1.035 1.035 1.035 1.037 1.037 1.037 1.021 1.031 1.031

8009 1.021 1.021 1.033 1.033 1.033 1.035 1.035 1.035 1.037 1.037 1.037 1.021 1.031 1.031

8020 1.019 1.019 1.029 1.029 1.029 1.030 1.030 1.030 1.034 1.034 1.034 1.019 1.027 1.028

8019 1.020 1.020 1.030 1.030 1.030 1.032 1.032 1.032 1.035 1.035 1.035 1.020 1.028 1.029

Table 43. Leichardt River – Evaporation scaling factors for Scenario Cdry


8001 1.046 1.046 1.057 1.057 1.057 1.061 1.061 1.061 1.051 1.051 1.051 1.046 1.052 1.053

8009 1.046 1.046 1.056 1.056 1.056 1.061 1.061 1.061 1.051 1.051 1.051 1.046 1.052 1.053

8020 1.046 1.046 1.056 1.056 1.056 1.061 1.061 1.061 1.051 1.051 1.051 1.046 1.052 1.053

8019 1.046 1.046 1.056 1.056 1.056 1.061 1.061 1.061 1.051 1.051 1.051 1.046 1.052 1.053


3.5 Flinders

Model overview

The Flinders catchment was modelled using the IQQM program (version 6.42.2). The models were set up by the

Department of Environment and Resource Management to support the Queensland Water Resource Planning Process.

Results from this model for the period from January 1890 to June 2003 were used to establish the water sharing rules in

the draft Gulf Resource Operations Plan (DNRW, 2008). The level of development represented by the model is based on

the full use of existing entitlements. It should be noted that the results presented in DERM reports (Water Assessment

Group, 2006b) may differ from numbers published in this report due to the different modelling period and different initial

conditions.


the period 1 January 1890 to 30 June 2008. The results for this project are reported for 77-year sequences. In this

project the river system modelling for the Flinders catchment consists of ten scenarios:

• Scenario A – historical climate sequence and full use of existing entitlements



the water accounted for in the draft Gulf Resource Operations Plan, but the licences are interim or not allocated

as yet. The period of analysis commences on 1 September 2007 and streamflow metrics are produced by

modelling the 77-year historical climate sequence between 1 September 2007 and 31 August 2084. This

scenario is used as a baseline for comparison with all other scenarios.










considered to be negligible. This scenario incorporates the effects of current land use and uses seven

consecutive climate sequences between 1 September 1996 and 31 August 2007 to generate a 77-year climate

sequence representative of the ‘recent climate’.
















analysed.



Flinders-Leichhardt rainfall-runoff chapter of the Gulf of Carpentaria report. These differences are due to differences in

the methods by which the GCMs were ranked and difference in areas that are considered to contribute runoff to the

surface water model. In the Flinders-Leichhardt rainfall-runoff chapter of the Gulf of Carpentaria report the entire region is

considered while a subset of this area is considered here. The scenarios presented in this project may not eventuate but

they encompass consequences that might arise if no management changes were made. Consequently, results from this

assessment are designed to highlight pressure points in the system, both now and in the future. This assessment does

not elaborate on what management actions might be taken to address any of these pressure points. Where management

changes to mitigate the effects of climate change have recently been implemented, the impacts of the changes predicted

in this section may be an overestimate.


The Flinders region is described by the Flinders IQQM system model (Water Assessment Group, 2006b). The model

extends from the headwaters of the Flinders catchment, in the east upstream of Hughenden on the Flinders River and in

the west upstream of Cloncurry on Cloncurry River, to the mouth of the Flinders River on the Gulf of Carpentaria west of

Karumba (Figure 15). The Cloncurry River joins the Flinders River just upstream of the outlet to the ocean. The Walkers

Bend gauge (915003a) is the most downstream flow monitoring station in the system. The tributaries of the Flinders

system include Porcupine Creek, Betts Creek, Dutton River, Mountain Creek, Stawell River and Woolgar River which

contribute to the Flinders River flows and Malbon River, Williams River, Gilliat River, Julia Creek, Corella River and

Dugald River which contribute to the Cloncurry River flows.

The system is represented in the model by 55 river sections and 170 nodes (Appendix 1). Twelve of these nodes are

water demand nodes which are used for simulating water-harvesting rules in the lower section of the basin. There are

two main storages represented in the model, Corella Dam and Chinaman Creek Dam, and ten smaller instream storages.

There are no passing flow requirements for the major storages. Details of the major storages in the Flinders catchment

are provided in Table 44. The degree of regulation metric presented in Table 44 is the sum of the net evaporation and

controlled releases from the dam divided by the total inflows. Controlled releases exclude spillage. Storages with radial

gates and without spillways are not reported in this table. The degree of regulation of Corella Dam for the full use of

existing entitlements is 0.41.

This model was developed as planning tools and consequently has been set up assuming full use of existing

entitlements. A consequence of this is that the model does not simulate current levels of development. Water use is

modelled by 49 nodes that are categorised into different uses in Table 45. Diversions are modelled from:

• 7 nodes for mining, industrial or town water supply purposes

• 27 nodes representing high flow (water harvesting) diversions (5 of these nodes are not direct users because

they divert water to other tributaries)

• 15 nodes representing unregulated diversions.


Figure 15. Schematic of the approximate location of gauging stations, main demand nodes and storages for the Flinders river system

model (green lines) and Leichhardt river system model (pink lines)

Table 44. Storages in the Flinders river system model

Major storages Active storage

Average annual Inflow




GL GL/y

Corella Dam 15.8 18.5 2.5 5.1 0.41

Chinaman Creek Dam 2.8 13.5 2.0 0.2 0.16

Other 3.8 243.6 2.8 1.0 0.02

Total 22.4 275.7 7.3 6.2 0.05

In Table 45 and the sections that follow, ‘volumetric limit’ is defined as being the maximum volume of water that can be

extracted from a river system within this region under the draft Gulf Resource Operations Plan. Unsupplemented water is

defined as surface water that is not sourced from a water storage that is able to regulate or control supply to users.


Table 45. Modelled water use configuration in the Flinders river system model


Volumetric limit Model notes

GL/y

Town Water Supply

High Security 2 3.5 Fixed demand

Unsupplemented 1 0.2 Fixed demand

Agriculture

General Security 5 20.2 No On Farm Storage

Unsupplemented 27 105.8 On Farm Storage

Other Demands



Total 44 133.696

Model setup

The original Flinders River model and associated IQQM V6.42.2 executable code were obtained from the Queensland

Department of Environment and Resource Management. The time series rainfall, evaporation and flow inputs to this

model for the historical climate time series were set to cover the reporting period 1 September 1930 to 31 August 2007.

The model was run for the reporting period and validated against the original model run results for the same period.

Model setup information for the Flinders river system model is summarised in Table 46.

For the scenarios that assume the full use of existing entitlements, the initial state of storages can influence the results

obtained so the same initial storage levels need to be used for all scenarios. In this project all scenarios are reported for

a common 77-year sequence commencing on 1 September 2007. However, the demand simulated by an IQQM model

for month n is dependent upon the simulation results for month n-1. For this reason the initial conditions (i.e. storage

levels) are set to the levels simulated on the 1 August 2007 for all scenarios. The models are then run for 77 years and

one month.

A without-development version of the Flinders model was created by removing all instream storages, all irrigators and

fixed demands.

Table 46. Flinders river system model setup information


Flinders IQQM 6.42.2 01/01/1890 20/08/2008

Connection

Baseline models

Warm up period 1/08/2007 31/08/2007

Flinders IQQM 6.42.2 1/09/2007 31/08/2084

Connection

Modifications

Data Data extended by DERM

Inflows

Initial storage volumes set to level at 01/08/2007

Corella 7.69 GL

Chinaman Creek Dam 2.55 GL

Other storages set to level at 01/08/2007



The mass balance table (Table 47) shows volumetric components under Scenario A as GL/year, with all other scenarios





listed based on the different water products in the region. End-of-system flows are shown for the Flinders River at

modelled end-of-system.

Mass balance tables for the river reaches in the model are provided in the following section. The mass balance of each

of these river reaches and the overall mass balance were checked by taking the difference between total inflows,

outflows of the system and change in storage volumes. In all cases the mass balance error was zero. Unattributed fluxes

in Table 47 are the modelled river losses. River losses are estimated from loss relationships that are determined during

calibration of the IQQM model such that flow is conserved between upstream and downstream gauging stations.

Results in Table 47 show that under scenarios Cwet and Cdry, inflows in the Flinders catchment increase by 32 percent

and decrease by 25 percent respectively. End-of-system flows increase by 33 percent and decrease by 26 percent under

scenarios Cwet and Cdry respectively. However, the impact of climate change on diversions is small (<8 percent) as

demands in the region are much smaller than the total inflows.

Table 47. Finders river system model mean annual water balance under Scenario A and under scenarios B and C relative to Scenario A

A B Cwet Cmid Cdry

GL/y

Storage volume



Inflows

Subcatchments

Gauged 535.8 2% 33% 0% -27%

Ungauged 2404.2 -8% 31% 3% -24%

Sub-total 2940.0 -6% 32% 2% -25%

Diversions

Agriculture

General Security 13.1 0% 3% -3% -6%

Unsupplemented 86.7 -2% 4% -2% -8%

Town Water Supply

High Security 3.3 -1% 0% 0% -1%

Unsupplemented 0.0 0% 5% -5% -5%

Other Uses



Sub-total 107.0 -1% 4% -2% -7%

Outflows

End-of-system flow 1981.9 -6% 33% 3% -26%

Sub-total 1981.9 -6% 33% 3% -26%

Net evaporation

Storages 10.0 1% 4% 3% -1%

Sub-total 10.0 1% 4% 3% -1%

Unattributed fluxes

841.0 -6% 33% 2% -26%



Annual water balances for individual reaches in the Flinders river system model are summarised in Table 48 to Table 57.

Table 48. Flinders River water balance – gauge 915999

915999 (EoS) A B Cwet Cmid Cdry

GL/y

Storage volume



Inflows

Subcatchments

Gauged 1937.9 -7% 33% 2% -26%

Ungauged 44.1 17% 10% 15% -24%

Sub-total 1982.0 -6% 33% 3% -26%

Diversions

Other Uses


Unsupplemented

Sub-total 0.0 0% 0% 0% -1%

Outflows

End of system flow 1981.9 -6% 33% 3% -26%

Sub-total 1981.9 -6% 33% 3% -26%

Net evaporation

Storages 0.0 -1% 1% 3% 8%

Sub-total 0.0 -1% 1% 3% 8%

Unattributed fluxes

0.0 475% 702% 329% 328%




Inflows

Subcatchments

Gauged 2114.3 -6% 39% -1% -27%

Ungauged 485.8 -11% 17% 20% -24%

Sub-total 2600.1 -7% 35% 3% -27%

Diversions

Agriculture

General Security


Sub-total 0.4 -1% 9% -1% -9%

Outflows


Sub-total 1937.9 -7% 33% 2% -26%

Net evaporation

Storages

Sub-total

Unattributed fluxes

661.9 -8% 39% 4% -29%




GL/y

Storage volume



Inflows

Subcatchments

Gauged

Ungauged 71.1 74% 39% 8% -25%

Sub-total 71.1 74% 39% 8% -25%

Diversions

Other Uses


Unsupplemented

Sub-total 2.5 0% 0% 0% 0%

Outflows


Sub-total 62.6 83% 44% 8% -28%

Net evaporation

Storages 5.1 3% 7% 5% -5%

Sub-total 5.1 3% 7% 5% -5%

Unattributed fluxes

0.9 28% 21% 4% -16%



GL/y

Storage volume



Inflows

Subcatchments

Gauged 477.3 60% 39% 6% -26%

Ungauged 786.7 -10% 34% 8% -24%

Sub-total 1264.0 17% 36% 7% -24%

Diversions

Agriculture



Sub-total 21.8 2% 4% 1% -6%

Outflows


Sub-total 1163.1 17% 38% 8% -26%

Net evaporation

Storages 0.0 -10% -3% 2% 11%

Sub-total 0.0 -10% -3% 2% 11%

Unattributed fluxes

79.1 7% 10% 1% -11%




GL/y

Storage volume



Inflows

Subcatchments

Gauged 149.9 81% 40% 6% -26%

Ungauged 137.2 68% 35% 3% -25%

Sub-total 287.1 75% 37% 5% -26%

Diversions

Agriculture

General Security


Town Water Supply

High Security 3.3 -1% 0% 0% -1%

Unsupplemented

Sub-total 5.5 1% 2% 0% -2%

Outflows


Sub-total 266.7 80% 40% 5% -27%

Net evaporation

Storages 0.2 0% 2% 3% 3%

Sub-total 0.2 0% 2% 3% 3%

Unattributed fluxes

14.7 13% 13% 1% -13%




Inflows

Subcatchments

Gauged 66.1 61% 39% 8% -25%

Ungauged 89.0 92% 39% 5% -26%

Sub-total 155.1 79% 39% 6% -26%

Diversions

Sub-total

Outflows


Sub-total 149.9 81% 40% 6% -26%

Net evaporation

Storages

Sub-total

Unattributed fluxes

5.2 16% 16% 2% -14%





Inflows

Subcatchments

Gauged 74.9 -28% 31% 11% -29%

Ungauged 28.9 -53% 33% -9% -28%

Sub-total 103.8 -35% 31% 5% -29%

Diversions

Sub-total

Outflows


Sub-total 88.0 -39% 35% 6% -32%

Net evaporation

Storages

Sub-total

Unattributed fluxes

15.8 -14% 10% 1% -11%



GL/y

Storage volume



Inflows

Subcatchments

Gauged 505.4 -33% 36% -12% -31%

Ungauged 532.2 -33% 37% -12% -24%

Sub-total 1037.6 -33% 36% -12% -27%

Diversions

Agriculture



Other Uses

High Security


Sub-total 57.0 -4% 4% -2% -7%

Outflows

End of system flow 951.2 -36% 39% -13% -29%

Sub-total 951.2 -36% 39% -13% -29%

Net evaporation

Storages 3.9 -1% 2% 1% 4%

Sub-total 3.9 -1% 2% 1% 4%

Unattributed fluxes

25.5 -12% 14% -6% -15%





Inflows

Subcatchments

Gauged 175.9 -10% 35% -19% -32%

Ungauged 206.6 -42% 34% -19% -27%

Sub-total 382.6 -27% 34% -19% -29%

Diversions

Agriculture



Other Uses

High Security


Sub-total 11.4 1% 5% -5% -11%

Outflows


Sub-total 347.7 -30% 37% -21% -31%

Net evaporation

Storages 0.9 -2% 2% -2% 0%

Sub-total 0.9 -2% 2% -2% 0%

Unattributed fluxes

22.6 0% 10% -8% -11%




Inflows

Subcatchments

Gauged 93.0 13% 32% -18% -30%

Ungauged 22.7 -51% 38% -19% -28%

Sub-total 115.7 0% 33% -18% -29%

Diversions

Agriculture

General Security


Town Water Supply

High Security


Other Uses

High Security

Unsupplemented 0.3 0% 0% 0% 0%

Sub-total 8.5 0% 4% -6% -11%

Outflows

End of system flow 91.9 0% 39% -21% -34%

Sub-total 91.9 0% 39% -21% -34%

Unattributed fluxes

15.3 0% 11% -9% -12%


Scaling results


in Figure 16. Donor to target catchment relationships for the Flinders catchment are illustrated in Figure 16. See

Petheram et al. (2009) for more details. Average monthly scaling factors for streamflow, rainfall and evaporation under

scenarios B and C are listed in Table 58 to Table 69. The catchment numbers in the scaling factor tables below refer to

the SRN numbers used for the rainfall-runoff modelling.



Inset shows area of calibration rainfall-runoff gauging stations


Table 58. Flinders River – Streamflow scaling factors for Scenario B


6001 1.173 1.164 1.578 1.803 1.978 1.436 1.238 1.303 0.790 0.643 0.731 1.175 1.309 1.269

6006 1.159 1.161 1.576 1.816 1.989 1.403 1.253 1.226 0.700 0.686 0.719 1.153 1.287 1.248

6008 1.179 1.176 1.637 1.857 2.063 1.444 1.243 1.322 0.674 0.647 0.708 1.196 1.328 1.283

6010 1.155 1.161 1.592 1.822 2.047 1.413 1.250 1.342 0.636 0.696 0.704 1.166 1.287 1.255

6016 1.194 1.191 1.641 1.868 2.116 1.280 1.226 1.765 0.163 0.772 0.692 1.211 1.333 1.301

6018 1.172 1.204 1.617 1.823 2.625 1.700 1.635 1.738 0.571 0.648 0.701 1.162 1.305 1.296

6022 1.149 1.198 1.639 1.750 2.623 1.794 1.929 1.553 0.461 0.607 0.661 1.169 1.305 1.279

6029 1.213 1.202 1.669 1.888 2.260 1.188 1.100 1.061 0.956 1.047 0.998 1.280 1.361 1.337

6030 1.191 1.214 1.562 2.010 1.906 1.253 1.206 1.045 1.011 1.092 1.003 1.232 1.385 1.333

6040 1.173 1.179 1.666 1.799 2.253 1.136 1.074 1.065 0.944 1.043 1.019 1.286 1.319 1.297

6300 1.209 1.208 1.631 1.934 2.639 1.108 1.023 1.030 1.071 1.043 1.041 1.296 1.335 1.359

6043 1.193 1.221 1.642 1.905 1.840 1.202 1.041 1.084 0.903 0.952 0.945 1.260 1.332 1.312

6046 1.194 1.202 1.589 1.882 1.885 1.234 1.193 1.040 1.023 1.056 0.996 1.230 1.375 1.325

6051 1.193 1.195 1.617 1.800 1.987 1.216 1.122 1.092 1.075 1.042 1.015 1.212 1.352 1.304

6002 1.211 1.211 1.695 1.884 2.166 1.377 1.225 1.189 0.771 0.752 0.751 1.253 1.379 1.317

6012 1.192 1.194 1.664 1.899 2.083 1.322 1.223 1.187 0.701 0.724 0.758 1.224 1.339 1.306

6019 1.157 1.206 1.677 1.880 2.671 1.928 1.773 1.805 0.665 0.616 0.650 1.173 1.329 1.298

6149 1.198 1.203 1.701 1.890 2.027 1.229 1.188 1.092 0.797 0.782 0.821 1.210 1.322 1.326

6032 1.201 1.194 1.611 1.868 2.217 1.191 1.120 1.050 0.970 1.041 1.009 1.237 1.366 1.339

6035 1.184 1.183 1.614 1.820 2.194 1.152 1.083 1.037 0.965 1.038 1.014 1.252 1.329 1.309

6048 1.199 1.202 1.601 1.829 1.995 1.196 1.144 1.063 1.072 1.052 1.017 1.236 1.355 1.330

6054 1.187 1.199 1.644 1.952 2.242 1.552 1.054 1.194 1.014 1.109 1.020 1.242 1.325 1.313

6058 1.028 1.048 1.485 1.983 2.515 1.552 1.034 1.113 0.335 0.623 0.671 0.995 1.156 1.148

6138 1.191 1.208 1.655 1.850 2.530 1.111 1.018 1.046 1.183 1.039 1.041 1.318 1.332 1.351

6178 1.185 1.194 1.667 1.980 2.227 1.243 1.168 1.090 0.814 0.761 0.846 1.203 1.301 1.318

6169 1.192 1.219 1.714 1.962 1.757 1.312 1.103 1.138 0.794 0.817 0.812 1.257 1.346 1.336

6124 1.205 1.235 1.695 2.046 1.796 1.307 1.088 1.109 0.828 0.826 0.839 1.246 1.373 1.346

6165 1.198 1.217 1.728 1.990 1.776 1.312 1.126 1.106 0.785 0.794 0.808 1.229 1.346 1.340

6026 1.213 1.192 1.633 1.950 2.315 1.453 1.130 1.418 1.046 0.669 0.640 1.236 1.342 1.322

6221 1.198 1.200 1.575 2.002 1.942 1.232 1.135 1.037 1.016 1.044 1.011 1.224 1.341 1.311

6160 0.941 0.946 1.520 1.661 2.207 1.526 0.992 1.232 1.381 0.437 0.725 0.910 1.086 1.069


Table 59. Flinders River – Rainfall scaling factors for Scenario B


6058 1.046 1.050 1.307 1.333 1.311 1.002 1.004 1.007 0.975 0.971 0.966 1.054 1.089 1.089

6002 1.084 1.084 1.297 1.301 1.304 1.027 1.027 1.027 0.985 0.978 0.975 1.087 1.109 1.108

6018 1.082 1.083 1.295 1.304 1.310 1.027 1.027 1.027 0.982 0.983 0.973 1.092 1.106 1.107

6016 1.084 1.083 1.297 1.305 1.301 1.027 1.027 1.027 0.978 0.976 0.977 1.089 1.113 1.113

6008 1.083 1.083 1.297 1.302 1.304 1.027 1.027 1.027 0.986 0.978 0.975 1.091 1.109 1.109

6012 1.084 1.083 1.297 1.304 1.300 1.027 1.027 1.027 0.986 0.976 0.976 1.089 1.110 1.110

6022 1.080 1.082 1.294 1.307 1.315 1.027 1.027 1.027 0.979 0.984 0.973 1.097 1.109 1.109

6010 1.082 1.082 1.296 1.302 1.307 1.027 1.027 1.027 0.985 0.980 0.974 1.093 1.108 1.108

6006 1.082 1.082 1.293 1.303 1.317 1.027 1.027 1.027 0.984 0.982 0.973 1.093 1.107 1.107

6026 1.087 1.085 1.298 1.310 1.301 1.026 1.026 1.026 0.978 0.978 0.982 1.093 1.117 1.115

6001 1.079 1.077 1.283 1.293 1.302 1.031 1.031 1.031 0.982 0.978 0.971 1.085 1.105 1.105

6019 1.082 1.082 1.295 1.306 1.312 1.027 1.027 1.027 0.978 0.980 0.975 1.095 1.110 1.110

6046 1.102 1.099 1.304 1.329 1.315 1.010 1.013 1.014 1.008 1.007 1.005 1.116 1.137 1.132

6035 1.102 1.101 1.304 1.321 1.321 1.011 1.012 1.016 1.004 1.007 1.006 1.114 1.134 1.131

6032 1.103 1.101 1.305 1.322 1.316 1.011 1.012 1.015 1.004 1.006 1.006 1.112 1.137 1.132

6030 1.103 1.099 1.306 1.323 1.313 1.011 1.012 1.014 1.006 1.007 1.006 1.115 1.137 1.132

6051 1.102 1.099 1.304 1.334 1.318 1.011 1.013 1.013 1.008 1.006 1.005 1.118 1.137 1.133

6300 1.103 1.099 1.307 1.320 1.311 1.011 1.012 1.017 1.005 1.007 1.006 1.117 1.131 1.130

6043 1.093 1.093 1.301 1.318 1.308 1.018 1.019 1.022 0.992 0.992 0.995 1.106 1.125 1.123

6048 1.102 1.099 1.304 1.328 1.322 1.011 1.012 1.014 1.007 1.006 1.006 1.119 1.137 1.133

6029 1.103 1.102 1.307 1.321 1.309 1.011 1.012 1.015 1.004 1.007 1.006 1.110 1.132 1.129

6040 1.101 1.100 1.305 1.322 1.317 1.010 1.012 1.017 1.005 1.007 1.005 1.117 1.132 1.131

6054 1.100 1.099 1.306 1.332 1.304 1.011 1.012 1.016 1.005 1.005 1.005 1.116 1.131 1.130

6046 1.102 1.099 1.304 1.329 1.315 1.010 1.013 1.014 1.008 1.007 1.005 1.116 1.137 1.133

Table 60. Flinders River – Evaporation scaling factors for Scenario B


6058 0.990 1.035 1.029 1.018 1.016 1.006 1.021 1.006 1.032 1.012 0.996 0.983 1.011 1.011

6002 0.959 0.974 0.995 0.984 0.996 0.995 1.002 0.991 1.018 0.993 0.959 0.951 0.981 0.982

6018 0.963 0.981 0.995 0.987 1.000 0.994 1.004 0.990 1.018 0.992 0.967 0.956 0.984 0.985

6016 0.972 1.001 1.009 1.002 1.000 1.000 1.013 0.998 1.023 1.004 0.980 0.973 0.996 0.996

6008 0.957 0.973 0.992 0.983 0.996 0.993 1.002 0.990 1.016 0.991 0.960 0.950 0.980 0.981

6012 0.965 0.986 1.001 0.992 0.998 0.998 1.008 0.995 1.020 0.998 0.968 0.961 0.988 0.988

6022 0.973 0.998 1.005 0.998 1.002 1.000 1.010 0.995 1.023 1.001 0.979 0.968 0.994 0.994

6010 0.960 0.977 0.994 0.985 0.998 0.993 1.003 0.991 1.017 0.991 0.963 0.953 0.982 0.983

6006 0.954 0.969 0.988 0.979 0.998 0.987 1.000 0.987 1.013 0.987 0.958 0.947 0.977 0.978

6026 0.982 1.021 1.019 1.011 1.006 1.003 1.018 1.004 1.029 1.012 0.989 0.982 1.004 1.005

6001 0.952 0.965 0.986 0.976 0.996 0.987 0.998 0.986 1.012 0.985 0.954 0.944 0.975 0.975

6019 0.970 0.993 1.003 0.995 1.000 0.999 1.009 0.994 1.021 0.999 0.975 0.965 0.991 0.992

6046 0.974 1.026 1.021 1.012 1.005 0.989 1.008 0.995 1.027 1.005 0.989 0.978 1.001 1.001

6035 0.987 1.045 1.033 1.024 1.016 0.999 1.020 1.010 1.039 1.016 1.002 0.991 1.014 1.014

6032 0.979 1.033 1.026 1.017 1.009 0.993 1.014 1.003 1.033 1.010 0.995 0.983 1.007 1.007

6030 0.972 1.024 1.020 1.011 1.003 0.987 1.007 0.995 1.026 1.005 0.988 0.978 1.000 1.000

6051 0.978 1.034 1.026 1.017 1.011 0.995 1.014 1.000 1.030 1.009 0.993 0.981 1.006 1.006

6300 0.986 1.038 1.028 1.021 1.012 1.001 1.021 1.011 1.036 1.016 0.997 0.987 1.012 1.012

6043 0.987 1.034 1.024 1.017 1.009 1.003 1.020 1.008 1.032 1.016 0.995 0.989 1.010 1.010

6048 0.980 1.037 1.027 1.018 1.012 0.995 1.014 1.001 1.032 1.010 0.995 0.984 1.008 1.008

6029 0.982 1.035 1.028 1.019 1.011 0.996 1.018 1.009 1.037 1.013 0.997 0.984 1.009 1.009

6040 0.989 1.046 1.033 1.025 1.017 1.001 1.022 1.012 1.040 1.017 1.002 0.992 1.015 1.015

6054 0.991 1.045 1.032 1.023 1.016 1.004 1.022 1.010 1.037 1.017 1.001 0.991 1.015 1.015

6046 0.974 1.026 1.021 1.012 1.005 0.989 1.008 0.995 1.027 1.005 0.989 0.978 1.001 1.001


Table 61. Flinders River – Streamflow scaling factors for Scenario Cwet


6001 1.173 1.164 1.578 1.803 1.978 1.436 1.238 1.303 0.790 0.643 0.731 1.175 1.309 1.269

6006 1.159 1.161 1.576 1.816 1.989 1.403 1.253 1.226 0.700 0.686 0.719 1.153 1.287 1.248

6008 1.179 1.176 1.637 1.857 2.063 1.444 1.243 1.322 0.674 0.647 0.708 1.196 1.328 1.283

6010 1.155 1.161 1.592 1.822 2.047 1.413 1.250 1.342 0.636 0.696 0.704 1.166 1.287 1.255

6016 1.194 1.191 1.641 1.868 2.116 1.280 1.226 1.765 0.163 0.772 0.692 1.211 1.333 1.301

6018 1.172 1.204 1.617 1.823 2.625 1.700 1.635 1.738 0.571 0.648 0.701 1.162 1.305 1.296

6022 1.149 1.198 1.639 1.750 2.623 1.794 1.929 1.553 0.461 0.607 0.661 1.169 1.305 1.279

6029 1.213 1.202 1.669 1.888 2.260 1.188 1.100 1.061 0.956 1.047 0.998 1.280 1.361 1.337

6030 1.191 1.214 1.562 2.010 1.906 1.253 1.206 1.045 1.011 1.092 1.003 1.232 1.385 1.333

6040 1.173 1.179 1.666 1.799 2.253 1.136 1.074 1.065 0.944 1.043 1.019 1.286 1.319 1.297

6300 1.209 1.208 1.631 1.934 2.639 1.108 1.023 1.030 1.071 1.043 1.041 1.296 1.335 1.359

6043 1.193 1.221 1.642 1.905 1.840 1.202 1.041 1.084 0.903 0.952 0.945 1.260 1.332 1.312

6046 1.194 1.202 1.589 1.882 1.885 1.234 1.193 1.040 1.023 1.056 0.996 1.230 1.375 1.325

6051 1.193 1.195 1.617 1.800 1.987 1.216 1.122 1.092 1.075 1.042 1.015 1.212 1.352 1.304

6002 1.211 1.211 1.695 1.884 2.166 1.377 1.225 1.189 0.771 0.752 0.751 1.253 1.379 1.317

6012 1.192 1.194 1.664 1.899 2.083 1.322 1.223 1.187 0.701 0.724 0.758 1.224 1.339 1.306

6019 1.157 1.206 1.677 1.880 2.671 1.928 1.773 1.805 0.665 0.616 0.650 1.173 1.329 1.298

6149 1.198 1.203 1.701 1.890 2.027 1.229 1.188 1.092 0.797 0.782 0.821 1.210 1.322 1.326

6032 1.201 1.194 1.611 1.868 2.217 1.191 1.120 1.050 0.970 1.041 1.009 1.237 1.366 1.339

6035 1.184 1.183 1.614 1.820 2.194 1.152 1.083 1.037 0.965 1.038 1.014 1.252 1.329 1.309

6048 1.199 1.202 1.601 1.829 1.995 1.196 1.144 1.063 1.072 1.052 1.017 1.236 1.355 1.330

6054 1.187 1.199 1.644 1.952 2.242 1.552 1.054 1.194 1.014 1.109 1.020 1.242 1.325 1.313

6058 1.028 1.048 1.485 1.983 2.515 1.552 1.034 1.113 0.335 0.623 0.671 0.995 1.156 1.148

6138 1.191 1.208 1.655 1.850 2.530 1.111 1.018 1.046 1.183 1.039 1.041 1.318 1.332 1.351

6178 1.185 1.194 1.667 1.980 2.227 1.243 1.168 1.090 0.814 0.761 0.846 1.203 1.301 1.318

6169 1.192 1.219 1.714 1.962 1.757 1.312 1.103 1.138 0.794 0.817 0.812 1.257 1.346 1.336

6124 1.205 1.235 1.695 2.046 1.796 1.307 1.088 1.109 0.828 0.826 0.839 1.246 1.373 1.346

6165 1.198 1.217 1.728 1.990 1.776 1.312 1.126 1.106 0.785 0.794 0.808 1.229 1.346 1.340

6026 1.213 1.192 1.633 1.950 2.315 1.453 1.130 1.418 1.046 0.669 0.640 1.236 1.342 1.322

6221 1.198 1.200 1.575 2.002 1.942 1.232 1.135 1.037 1.016 1.044 1.011 1.224 1.341 1.311

6160 0.941 0.946 1.520 1.661 2.207 1.526 0.992 1.232 1.381 0.437 0.725 0.910 1.086 1.069


Table 62. Flinders River – Streamflow scaling factors for Scenario Cmid


6001 0.884 0.866 0.745 0.692 0.653 0.924 1.083 1.274 0.709 0.535 0.641 0.841 0.826 0.832

6006 0.989 0.930 0.814 0.763 0.748 0.992 1.125 1.354 0.646 0.642 0.632 0.987 0.913 0.925

6008 0.821 0.815 0.701 0.652 0.603 0.904 1.054 1.261 0.595 0.584 0.623 0.786 0.779 0.788

6010 0.863 0.851 0.744 0.687 0.646 0.942 1.071 1.257 0.590 0.672 0.625 0.850 0.823 0.827

6016 0.857 0.852 0.727 0.653 0.594 0.977 1.066 1.922 0.095 0.638 0.527 0.863 0.814 0.822

6018 1.182 1.132 0.995 0.960 0.943 1.135 1.362 1.707 0.515 0.540 0.495 1.156 1.112 1.101

6022 1.211 1.163 1.001 0.964 0.963 1.177 1.509 1.639 0.454 0.539 0.486 1.277 1.138 1.145

6029 1.075 1.068 0.999 0.948 0.970 1.170 1.180 1.252 0.837 0.320 0.706 1.084 1.048 1.047

6030 1.058 1.053 1.300 1.485 1.472 1.174 1.141 1.101 0.762 0.360 0.699 1.048 1.170 1.128

6040 1.049 1.044 1.004 0.957 0.984 1.196 1.167 1.282 0.764 0.672 0.770 1.043 1.033 1.032

6300 1.073 1.074 1.018 0.984 1.012 1.212 1.173 1.248 0.715 0.744 0.720 1.081 1.058 1.056

6043 1.059 1.064 1.012 0.970 1.011 1.192 1.164 1.354 0.535 0.748 0.685 1.061 1.048 1.049

6046 1.055 1.048 1.291 1.388 1.450 1.154 1.134 1.086 0.783 0.478 0.704 1.032 1.154 1.112

6051 1.043 1.043 1.130 1.116 1.213 1.148 1.119 1.220 0.712 0.654 0.743 1.023 1.072 1.053

6002 0.875 0.863 0.712 0.668 0.585 0.928 1.076 1.218 0.665 0.614 0.573 0.853 0.812 0.823

6012 0.852 0.845 0.712 0.651 0.604 0.957 1.065 1.198 0.622 0.581 0.626 0.848 0.807 0.815

6019 0.962 0.943 0.809 0.776 0.679 0.977 1.234 1.465 0.564 0.577 0.506 0.925 0.911 0.916

6149 0.869 0.854 0.719 0.650 0.685 1.025 1.145 1.143 0.667 0.636 0.677 0.892 0.830 0.829

6032 1.069 1.060 1.032 0.996 1.026 1.168 1.168 1.212 0.833 0.346 0.719 1.074 1.051 1.048

6035 1.057 1.051 1.003 0.951 0.972 1.185 1.161 1.218 0.842 0.608 0.735 1.055 1.036 1.032

6048 1.046 1.046 1.044 1.002 1.046 1.143 1.133 1.207 0.759 0.611 0.757 1.023 1.042 1.040

6054 1.135 1.098 1.014 0.947 0.980 1.096 1.185 1.414 0.551 0.255 0.555 1.156 1.089 1.087

6058 1.298 1.203 1.021 0.899 0.881 1.078 1.240 1.369 0.125 0.336 0.511 1.417 1.202 1.208

6138 1.065 1.068 1.014 0.980 1.006 1.235 1.156 1.335 0.404 0.777 0.718 1.064 1.051 1.049

6178 0.874 0.854 0.731 0.629 0.618 1.040 1.122 1.138 0.708 0.629 0.707 0.884 0.835 0.831

6169 0.907 0.877 0.723 0.653 0.743 0.969 1.159 1.221 0.683 0.698 0.646 0.877 0.847 0.850

6124 0.912 0.879 0.736 0.648 0.748 0.978 1.135 1.169 0.707 0.681 0.662 0.887 0.847 0.855

6165 0.893 0.868 0.726 0.641 0.737 0.998 1.162 1.171 0.662 0.672 0.663 0.895 0.842 0.843

6026 0.959 0.964 0.875 0.782 0.808 1.015 1.157 1.448 1.206 0.471 0.402 0.962 0.934 0.938

6221 1.055 1.047 1.008 0.956 0.960 1.130 1.146 1.203 0.888 0.606 0.776 1.035 1.032 1.028

6160 1.246 1.164 0.972 0.933 0.901 1.393 1.487 1.358 1.142 0.385 0.688 1.349 1.158 1.169


Table 63. Flinders River – Streamflow scaling factors for Scenario Cdry


6001 0.663 0.658 0.774 0.831 0.845 0.918 0.941 0.895 0.823 0.783 0.817 0.596 0.704 0.702

6006 0.677 0.655 0.766 0.825 0.853 0.932 0.936 0.894 0.805 0.846 0.817 0.629 0.704 0.695

6008 0.657 0.645 0.774 0.841 0.858 0.919 0.912 0.873 0.703 0.788 0.795 0.587 0.695 0.681

6010 0.684 0.669 0.742 0.783 0.801 0.952 0.976 0.861 0.735 0.822 0.781 0.622 0.701 0.698

6016 0.802 0.794 0.590 0.464 0.422 1.195 1.590 7.959 0.127 0.512 0.396 0.749 0.734 0.753

6018 0.722 0.698 0.724 0.770 0.693 0.893 1.004 1.261 0.710 0.696 0.696 0.593 0.711 0.709

6022 0.779 0.771 0.604 0.562 0.310 0.989 1.507 2.338 0.508 0.388 0.323 0.571 0.721 0.716

6029 0.827 0.818 0.588 0.452 0.403 1.424 1.479 1.745 0.846 0.058 0.510 0.766 0.752 0.765

6030 0.840 0.817 0.698 0.568 0.571 0.816 0.813 0.928 0.479 0.017 0.414 0.801 0.760 0.763

6040 0.831 0.804 0.596 0.486 0.416 1.495 1.418 1.833 0.708 0.355 0.539 0.719 0.758 0.766

6300 0.857 0.853 0.617 0.488 0.427 1.550 1.456 1.683 0.657 0.563 0.523 0.789 0.798 0.800

6043 0.859 0.843 0.604 0.423 0.564 1.416 1.451 2.035 0.326 0.575 0.495 0.808 0.789 0.799

6046 0.841 0.815 0.692 0.540 0.562 0.828 0.825 0.880 0.501 0.129 0.447 0.805 0.760 0.758

6051 0.837 0.835 0.642 0.507 0.534 1.136 1.173 1.381 0.456 0.371 0.519 0.791 0.761 0.773

6002 0.669 0.650 0.832 0.893 0.868 0.933 0.886 0.946 0.712 0.780 0.748 0.610 0.723 0.706

6012 0.751 0.737 0.669 0.634 0.623 1.084 1.287 1.424 0.741 0.554 0.626 0.703 0.728 0.730

6019 0.780 0.771 0.596 0.527 0.303 1.024 1.584 2.694 0.807 0.393 0.316 0.578 0.718 0.720

6149 0.845 0.839 0.583 0.462 0.558 1.376 1.755 1.624 0.551 0.480 0.551 0.810 0.783 0.785

6032 0.830 0.817 0.632 0.461 0.407 1.389 1.415 1.601 0.774 0.125 0.520 0.802 0.747 0.760

6035 0.839 0.815 0.624 0.463 0.414 1.472 1.412 1.626 0.799 0.322 0.514 0.773 0.760 0.769

6048 0.834 0.831 0.648 0.462 0.497 1.250 1.279 1.522 0.613 0.291 0.547 0.781 0.758 0.769

6054 0.831 0.829 0.611 0.429 0.472 0.961 1.495 2.290 0.529 0.063 0.310 0.767 0.770 0.771

6058 0.806 0.806 0.631 0.463 0.393 1.087 1.649 2.639 0.102 0.115 0.290 0.746 0.759 0.758

6138 0.858 0.852 0.606 0.498 0.445 1.670 1.424 1.976 0.408 0.588 0.532 0.788 0.792 0.803

6178 0.848 0.840 0.613 0.451 0.486 1.420 1.662 1.620 0.609 0.491 0.580 0.809 0.795 0.791

6169 0.862 0.848 0.571 0.407 0.606 1.251 1.698 1.928 0.572 0.576 0.498 0.804 0.783 0.788

6124 0.857 0.843 0.579 0.420 0.584 1.254 1.597 1.711 0.612 0.568 0.542 0.820 0.773 0.786

6165 0.853 0.838 0.572 0.410 0.598 1.292 1.710 1.772 0.587 0.541 0.528 0.810 0.779 0.782

6026 0.807 0.817 0.603 0.415 0.495 1.122 1.543 4.215 5.709 0.271 0.211 0.759 0.752 0.761

6221 0.832 0.826 0.649 0.497 0.468 1.258 1.361 1.538 0.843 0.315 0.571 0.786 0.764 0.776

6160 0.814 0.802 0.659 0.622 0.564 1.914 2.135 1.706 1.150 0.117 0.516 0.767 0.767 0.783


Table 64. Flinders River – Rainfall scaling factors for Scenario Cwet


6058 1.046 1.050 1.307 1.333 1.311 1.002 1.004 1.007 0.975 0.971 0.966 1.054 1.089 1.089

6002 1.084 1.084 1.297 1.301 1.304 1.027 1.027 1.027 0.985 0.978 0.975 1.087 1.109 1.108

6018 1.082 1.083 1.295 1.304 1.310 1.027 1.027 1.027 0.982 0.983 0.973 1.092 1.106 1.107

6016 1.084 1.083 1.297 1.305 1.301 1.027 1.027 1.027 0.978 0.976 0.977 1.089 1.113 1.113

6008 1.083 1.083 1.297 1.302 1.304 1.027 1.027 1.027 0.986 0.978 0.975 1.091 1.109 1.109

6012 1.084 1.083 1.297 1.304 1.300 1.027 1.027 1.027 0.986 0.976 0.976 1.089 1.110 1.110

6022 1.080 1.082 1.294 1.307 1.315 1.027 1.027 1.027 0.979 0.984 0.973 1.097 1.109 1.109

6010 1.082 1.082 1.296 1.302 1.307 1.027 1.027 1.027 0.985 0.980 0.974 1.093 1.108 1.108

6006 1.082 1.082 1.293 1.303 1.317 1.027 1.027 1.027 0.984 0.982 0.973 1.093 1.107 1.107

6026 1.087 1.085 1.298 1.310 1.301 1.026 1.026 1.026 0.978 0.978 0.982 1.093 1.117 1.115

6001 1.079 1.077 1.283 1.293 1.302 1.031 1.031 1.031 0.982 0.978 0.971 1.085 1.105 1.105

6019 1.082 1.082 1.295 1.306 1.312 1.027 1.027 1.027 0.978 0.980 0.975 1.095 1.110 1.110

6046 1.102 1.099 1.304 1.329 1.315 1.010 1.013 1.014 1.008 1.007 1.005 1.116 1.137 1.132

6035 1.102 1.101 1.304 1.321 1.321 1.011 1.012 1.016 1.004 1.007 1.006 1.114 1.134 1.131

6032 1.103 1.101 1.305 1.322 1.316 1.011 1.012 1.015 1.004 1.006 1.006 1.112 1.137 1.132

6030 1.103 1.099 1.306 1.323 1.313 1.011 1.012 1.014 1.006 1.007 1.006 1.115 1.137 1.132

6051 1.102 1.099 1.304 1.334 1.318 1.011 1.013 1.013 1.008 1.006 1.005 1.118 1.137 1.133

6300 1.103 1.099 1.307 1.320 1.311 1.011 1.012 1.017 1.005 1.007 1.006 1.117 1.131 1.130

6043 1.093 1.093 1.301 1.318 1.308 1.018 1.019 1.022 0.992 0.992 0.995 1.106 1.125 1.123

6048 1.102 1.099 1.304 1.328 1.322 1.011 1.012 1.014 1.007 1.006 1.006 1.119 1.137 1.133

6029 1.103 1.102 1.307 1.321 1.309 1.011 1.012 1.015 1.004 1.007 1.006 1.110 1.132 1.129

6040 1.101 1.100 1.305 1.322 1.317 1.010 1.012 1.017 1.005 1.007 1.005 1.117 1.132 1.131

6054 1.100 1.099 1.306 1.332 1.304 1.011 1.012 1.016 1.005 1.005 1.005 1.116 1.131 1.130

6046 1.102 1.099 1.304 1.329 1.315 1.010 1.013 1.014 1.008 1.007 1.005 1.116 1.137 1.133

Table 65 Flinders River – Rainfall scaling factors for Scenario Cmid


6058 1.056 1.041 0.964 0.957 0.962 1.063 1.062 1.061 0.881 0.892 0.895 1.043 1.018 1.018

6002 0.950 0.950 0.878 0.877 0.877 1.039 1.038 1.037 0.873 0.879 0.882 0.953 0.932 0.933

6018 1.033 1.020 0.974 0.976 0.979 1.069 1.069 1.068 0.858 0.858 0.867 1.008 0.994 0.996

6016 0.950 0.948 0.878 0.877 0.877 1.040 1.038 1.035 0.879 0.881 0.880 0.955 0.933 0.933

6008 0.947 0.948 0.878 0.878 0.877 1.039 1.039 1.037 0.872 0.879 0.882 0.960 0.932 0.933

6012 0.949 0.949 0.878 0.877 0.878 1.039 1.038 1.037 0.873 0.880 0.881 0.956 0.933 0.934

6022 1.034 1.022 0.979 0.978 0.977 1.070 1.070 1.068 0.860 0.858 0.867 1.014 0.999 1.000

6010 0.957 0.955 0.889 0.890 0.889 1.043 1.042 1.041 0.870 0.875 0.881 0.969 0.940 0.941

6006 0.980 0.973 0.918 0.918 0.916 1.051 1.051 1.051 0.866 0.869 0.877 0.987 0.957 0.958

6026 0.992 0.990 0.931 0.920 0.930 1.048 1.047 1.041 0.882 0.884 0.881 0.996 0.971 0.971

6001 0.958 0.956 0.890 0.888 0.887 1.042 1.043 1.039 0.870 0.876 0.881 0.965 0.939 0.940

6019 0.977 0.973 0.912 0.912 0.912 1.050 1.049 1.047 0.871 0.871 0.876 0.981 0.956 0.956

6046 1.019 1.018 1.127 1.118 1.129 1.028 1.024 1.019 0.890 0.899 0.892 1.010 1.028 1.025

6035 1.033 1.031 0.985 0.977 0.977 1.059 1.056 1.048 0.862 0.888 0.883 1.033 1.005 1.005

6032 1.032 1.030 0.999 0.990 0.994 1.055 1.053 1.048 0.867 0.887 0.885 1.031 1.007 1.007

6030 1.017 1.018 1.135 1.129 1.137 1.026 1.023 1.019 0.882 0.900 0.893 1.008 1.030 1.027

6051 1.026 1.024 1.047 1.037 1.047 1.044 1.041 1.038 0.899 0.889 0.885 1.026 1.016 1.015

6300 1.032 1.031 0.984 0.977 0.982 1.059 1.056 1.045 0.866 0.889 0.882 1.034 1.007 1.007

6043 1.033 1.029 0.985 0.975 0.981 1.058 1.057 1.046 0.881 0.887 0.881 1.037 1.008 1.008

6048 1.031 1.028 1.004 0.992 0.998 1.054 1.051 1.048 0.884 0.887 0.883 1.033 1.008 1.008

6029 1.033 1.032 0.984 0.977 0.983 1.059 1.055 1.051 0.860 0.889 0.883 1.032 1.004 1.004

6040 1.033 1.030 0.985 0.977 0.979 1.059 1.056 1.046 0.869 0.892 0.880 1.035 1.006 1.006

6054 1.041 1.036 0.981 0.970 0.982 1.059 1.057 1.050 0.882 0.890 0.885 1.040 1.012 1.012

6046 1.019 1.018 1.127 1.118 1.129 1.028 1.024 1.019 0.890 0.899 0.892 1.010 1.028 1.026


Table 66. Flinders River – Rainfall scaling factors for Scenario Cdry


6058 0.957 0.959 0.744 0.696 0.737 1.161 1.161 1.161 0.820 0.826 0.825 0.968 0.913 0.911

6002 0.891 0.890 1.005 1.007 1.010 0.982 0.979 0.975 0.949 0.953 0.954 0.894 0.930 0.929

6018 0.912 0.914 0.914 0.922 0.926 1.041 1.037 1.030 0.910 0.908 0.915 0.920 0.921 0.922

6016 0.960 0.958 0.742 0.724 0.732 1.161 1.161 1.161 0.826 0.828 0.824 0.966 0.912 0.912

6008 0.891 0.890 1.004 1.009 1.011 0.981 0.980 0.976 0.946 0.949 0.955 0.894 0.928 0.928

6012 0.934 0.931 0.843 0.841 0.854 1.091 1.086 1.076 0.874 0.882 0.881 0.937 0.920 0.920

6022 0.954 0.956 0.742 0.729 0.721 1.161 1.161 1.161 0.836 0.824 0.824 0.978 0.913 0.914

6010 0.899 0.900 0.968 0.976 0.982 1.005 1.000 0.993 0.931 0.932 0.943 0.904 0.925 0.925

6006 0.890 0.891 1.001 1.010 1.022 0.981 0.978 0.980 0.941 0.948 0.957 0.895 0.928 0.928

6026 0.960 0.958 0.744 0.715 0.735 1.161 1.161 1.161 0.826 0.829 0.823 0.966 0.912 0.913

6001 0.891 0.890 1.001 1.011 1.020 0.981 0.982 0.972 0.943 0.950 0.956 0.895 0.929 0.929

6019 0.955 0.956 0.742 0.729 0.724 1.161 1.161 1.161 0.836 0.829 0.822 0.978 0.913 0.914

6046 0.969 0.969 0.828 0.818 0.825 1.009 1.014 1.013 0.829 0.826 0.819 0.981 0.921 0.924

6035 0.960 0.958 0.746 0.719 0.719 1.161 1.161 1.161 0.813 0.829 0.825 0.967 0.905 0.908

6032 0.960 0.960 0.753 0.727 0.737 1.147 1.147 1.146 0.812 0.827 0.826 0.967 0.905 0.908

6030 0.970 0.969 0.832 0.828 0.831 1.001 1.005 1.011 0.817 0.827 0.820 0.982 0.923 0.925

6051 0.964 0.961 0.781 0.750 0.771 1.092 1.095 1.088 0.838 0.827 0.820 0.976 0.912 0.915

6300 0.959 0.958 0.742 0.721 0.735 1.161 1.161 1.161 0.817 0.829 0.824 0.967 0.911 0.912

6043 0.958 0.960 0.745 0.712 0.731 1.161 1.161 1.161 0.824 0.829 0.823 0.966 0.911 0.913

6048 0.961 0.959 0.757 0.724 0.733 1.140 1.141 1.140 0.835 0.826 0.822 0.970 0.905 0.909

6029 0.959 0.959 0.743 0.719 0.737 1.161 1.161 1.161 0.811 0.832 0.823 0.965 0.907 0.910

6040 0.960 0.957 0.745 0.718 0.726 1.161 1.161 1.161 0.820 0.833 0.821 0.969 0.908 0.910

6054 0.958 0.959 0.742 0.701 0.746 1.161 1.161 1.161 0.826 0.830 0.823 0.968 0.911 0.912

6046 0.969 0.969 0.828 0.818 0.825 1.009 1.014 1.013 0.829 0.826 0.819 0.981 0.921 0.927

Table 67. Flinders River – Evaporation scaling factors for Scenario Cwet


6058 1.035 1.036 1.017 1.017 1.017 1.035 1.035 1.035 1.030 1.030 1.030 1.036 1.030 1.030

6002 1.029 1.029 1.012 1.012 1.012 1.032 1.032 1.032 1.030 1.030 1.030 1.029 1.026 1.026

6018 1.028 1.028 1.011 1.011 1.011 1.030 1.030 1.030 1.030 1.030 1.030 1.028 1.025 1.025

6016 1.029 1.029 1.013 1.013 1.013 1.032 1.032 1.032 1.030 1.030 1.030 1.029 1.026 1.026

6008 1.028 1.028 1.011 1.011 1.011 1.031 1.031 1.031 1.030 1.030 1.030 1.028 1.026 1.026

6012 1.029 1.029 1.013 1.013 1.013 1.032 1.032 1.032 1.030 1.030 1.030 1.029 1.026 1.026

6022 1.028 1.028 1.012 1.012 1.012 1.031 1.031 1.031 1.030 1.030 1.030 1.028 1.026 1.026

6010 1.028 1.028 1.011 1.011 1.011 1.030 1.030 1.030 1.030 1.030 1.030 1.028 1.025 1.025

6006 1.028 1.028 1.010 1.010 1.010 1.030 1.030 1.030 1.030 1.030 1.030 1.028 1.025 1.025

6026 1.028 1.028 1.014 1.014 1.014 1.033 1.033 1.033 1.030 1.030 1.030 1.028 1.026 1.026

6001 1.030 1.030 1.011 1.011 1.011 1.030 1.030 1.030 1.030 1.030 1.030 1.030 1.026 1.026

6019 1.029 1.029 1.012 1.012 1.012 1.031 1.031 1.031 1.030 1.030 1.030 1.029 1.026 1.026

6046 1.021 1.021 1.017 1.017 1.017 1.035 1.035 1.035 1.028 1.028 1.028 1.021 1.025 1.025

6035 1.021 1.021 1.018 1.018 1.018 1.035 1.035 1.035 1.028 1.028 1.028 1.021 1.025 1.025

6032 1.021 1.021 1.018 1.018 1.018 1.035 1.035 1.035 1.028 1.028 1.028 1.021 1.025 1.025

6030 1.021 1.021 1.018 1.018 1.018 1.035 1.035 1.035 1.028 1.028 1.028 1.021 1.025 1.025

6051 1.021 1.021 1.017 1.017 1.017 1.035 1.035 1.035 1.028 1.028 1.028 1.021 1.025 1.025

6300 1.021 1.021 1.017 1.017 1.017 1.035 1.035 1.035 1.028 1.028 1.028 1.021 1.025 1.025

6043 1.024 1.024 1.016 1.016 1.016 1.034 1.034 1.034 1.029 1.029 1.029 1.024 1.025 1.026

6048 1.021 1.021 1.017 1.017 1.017 1.035 1.035 1.035 1.028 1.028 1.028 1.021 1.025 1.025

6029 1.021 1.021 1.018 1.018 1.018 1.035 1.035 1.035 1.028 1.028 1.028 1.021 1.025 1.025

6040 1.021 1.021 1.017 1.017 1.017 1.035 1.035 1.035 1.028 1.028 1.028 1.021 1.025 1.025

6054 1.021 1.021 1.017 1.017 1.017 1.035 1.035 1.035 1.028 1.028 1.028 1.021 1.025 1.025

6046 1.021 1.021 1.017 1.017 1.017 1.035 1.035 1.035 1.028 1.028 1.028 1.021 1.025 1.025


Table 68. Flinders River – Evaporation scaling factors for Scenario Cmid


6058 1.014 1.014 1.031 1.030 1.030 1.029 1.029 1.029 1.032 1.032 1.032 1.014 1.026 1.026

6002 1.017 1.017 1.035 1.035 1.035 1.031 1.031 1.031 1.034 1.034 1.034 1.017 1.029 1.029

6018 1.012 1.012 1.029 1.029 1.029 1.026 1.026 1.026 1.029 1.029 1.029 1.012 1.024 1.024

6016 1.018 1.018 1.036 1.036 1.036 1.032 1.032 1.032 1.034 1.034 1.034 1.018 1.029 1.029

6008 1.017 1.017 1.035 1.035 1.035 1.031 1.031 1.031 1.033 1.033 1.033 1.017 1.028 1.028

6012 1.018 1.018 1.035 1.035 1.035 1.032 1.032 1.032 1.034 1.034 1.034 1.018 1.029 1.029

6022 1.012 1.012 1.030 1.030 1.030 1.027 1.027 1.027 1.029 1.029 1.029 1.012 1.024 1.024

6010 1.017 1.017 1.034 1.034 1.034 1.030 1.030 1.030 1.033 1.033 1.033 1.017 1.028 1.028

6006 1.015 1.015 1.032 1.032 1.032 1.028 1.028 1.028 1.032 1.032 1.032 1.015 1.026 1.026

6026 1.018 1.018 1.035 1.035 1.035 1.033 1.033 1.033 1.035 1.035 1.035 1.018 1.029 1.030

6001 1.016 1.016 1.034 1.034 1.034 1.030 1.030 1.030 1.033 1.033 1.033 1.016 1.028 1.028

6019 1.016 1.016 1.033 1.033 1.033 1.030 1.030 1.030 1.032 1.032 1.032 1.016 1.027 1.027

6046 1.021 1.021 1.034 1.034 1.034 1.035 1.035 1.035 1.037 1.037 1.037 1.021 1.031 1.031

6035 1.019 1.019 1.035 1.035 1.035 1.034 1.034 1.034 1.037 1.037 1.037 1.019 1.030 1.031

6032 1.019 1.019 1.034 1.034 1.034 1.034 1.034 1.034 1.037 1.037 1.037 1.019 1.030 1.031

6030 1.021 1.021 1.034 1.034 1.034 1.035 1.035 1.035 1.037 1.037 1.037 1.021 1.031 1.031

6051 1.020 1.020 1.034 1.034 1.034 1.035 1.035 1.035 1.037 1.037 1.037 1.020 1.030 1.031

6300 1.019 1.019 1.035 1.035 1.035 1.034 1.034 1.034 1.037 1.037 1.037 1.019 1.030 1.031

6043 1.019 1.019 1.034 1.034 1.034 1.034 1.034 1.034 1.037 1.037 1.037 1.019 1.030 1.031

6048 1.019 1.019 1.034 1.034 1.034 1.034 1.034 1.034 1.037 1.037 1.037 1.019 1.030 1.031

6029 1.019 1.019 1.034 1.034 1.034 1.034 1.034 1.034 1.037 1.037 1.037 1.019 1.030 1.030

6040 1.019 1.019 1.034 1.034 1.034 1.034 1.034 1.034 1.037 1.037 1.037 1.019 1.030 1.030

6054 1.018 1.018 1.034 1.034 1.034 1.033 1.033 1.033 1.036 1.036 1.036 1.018 1.029 1.030

6046 1.021 1.021 1.034 1.034 1.034 1.035 1.035 1.035 1.037 1.037 1.037 1.021 1.031 1.031

Table 69. Flinders River – Evaporation scaling factors for Scenario Cdry


6058 1.046 1.046 1.053 1.053 1.053 1.058 1.058 1.058 1.052 1.052 1.052 1.046 1.051 1.052

6002 1.048 1.048 1.045 1.045 1.045 1.048 1.048 1.048 1.046 1.046 1.046 1.048 1.046 1.046

6018 1.046 1.046 1.046 1.046 1.046 1.050 1.050 1.050 1.047 1.047 1.047 1.046 1.047 1.047

6016 1.046 1.046 1.053 1.053 1.053 1.058 1.058 1.058 1.052 1.052 1.052 1.046 1.051 1.051

6008 1.047 1.047 1.044 1.044 1.044 1.047 1.047 1.047 1.045 1.045 1.045 1.047 1.046 1.046

6012 1.046 1.046 1.050 1.050 1.050 1.054 1.054 1.054 1.049 1.049 1.049 1.046 1.049 1.049

6022 1.045 1.045 1.052 1.052 1.052 1.057 1.057 1.057 1.051 1.051 1.051 1.045 1.050 1.051

6010 1.047 1.047 1.045 1.045 1.045 1.048 1.048 1.048 1.046 1.046 1.046 1.047 1.046 1.046

6006 1.047 1.047 1.043 1.043 1.043 1.046 1.046 1.046 1.045 1.045 1.045 1.047 1.045 1.045

6026 1.046 1.046 1.053 1.053 1.053 1.058 1.058 1.058 1.052 1.052 1.052 1.046 1.051 1.052

6001 1.047 1.047 1.044 1.044 1.044 1.047 1.047 1.047 1.045 1.045 1.045 1.047 1.046 1.046

6019 1.045 1.045 1.052 1.052 1.052 1.057 1.057 1.057 1.051 1.051 1.051 1.045 1.051 1.051

6046 1.046 1.046 1.055 1.055 1.055 1.060 1.060 1.060 1.051 1.051 1.051 1.046 1.052 1.052

6035 1.046 1.046 1.053 1.053 1.053 1.058 1.058 1.058 1.051 1.051 1.051 1.046 1.051 1.052

6032 1.046 1.046 1.054 1.054 1.054 1.058 1.058 1.058 1.051 1.051 1.051 1.046 1.051 1.052

6030 1.046 1.046 1.056 1.056 1.056 1.060 1.060 1.060 1.051 1.051 1.051 1.046 1.052 1.052

6051 1.046 1.046 1.054 1.054 1.054 1.059 1.059 1.059 1.051 1.051 1.051 1.046 1.052 1.052

6300 1.046 1.046 1.053 1.053 1.053 1.058 1.058 1.058 1.052 1.052 1.052 1.046 1.051 1.052

6043 1.046 1.046 1.053 1.053 1.053 1.058 1.058 1.058 1.052 1.052 1.052 1.046 1.051 1.052

6048 1.046 1.046 1.054 1.054 1.054 1.058 1.058 1.058 1.051 1.051 1.051 1.046 1.051 1.052

6029 1.046 1.046 1.053 1.053 1.053 1.058 1.058 1.058 1.051 1.051 1.051 1.046 1.051 1.051

6040 1.046 1.046 1.053 1.053 1.053 1.058 1.058 1.058 1.052 1.052 1.052 1.046 1.051 1.052

6054 1.046 1.046 1.053 1.053 1.053 1.058 1.058 1.058 1.052 1.052 1.052 1.046 1.051 1.052

6046 1.046 1.046 1.055 1.055 1.055 1.060 1.060 1.060 1.051 1.051 1.051 1.046 1.052 1.052


3.6 Gilbert

Model overview

The Gilbert catchment is modelled using the IQQM program (version 6.42.2). The model was set up by the Queensland

Department of Environment and Resource Management (QDERM) to support the Queensland Water Resource Planning

Process. Results from this model for the period from January 1890 to June 2003 were used to establish the water

sharing rules in the draft Gulf Resource Operations Plan (DNRW, 2008). The level of development represented by the

model is based on the full use of existing entitlements.


the period 1 January 1890 to 30 June 2008. The results for this project are presented over 77-year sequences for the

common modelling period 1 September 2007 to 31 August 2084. Results presented in DERM reports (Water

Assessment Group, 2006c) may differ from numbers published in this report due to the different modelling period and

different initial conditions.

In this project the river system modelling for the Gilbert catchment consist of ten scenarios:

• Scenario A – historical climate and full use of existing entitlements



the water accounted for in the resources operation plan, but the licences are interim or not allocated as yet. The

period of analysis commences on 1 September 2007 and the results are reported based on modelling the 77-

year historical climate sequence between 1 September 2007 and 31 August 2084. This scenario is used as a

baseline for comparison with all other scenarios.

• Scenario AN – historical climate and without development

Current levels of development such as storages and demand nodes are removed from the model to represent


or farm dam development because the impact of these factors on catchment yield are currently considered to

be negligible. This scenario uses the historical flow and climate inputs used for Scenario A.


Current levels of development such as storages and demand nodes are removed from the model to represent


or farm dam development because the impact of these factors on catchment yield are currently considered to

be negligible. This scenario uses seven consecutive climate sequences between 1 September 1996 and 31

August 2007 to generate a 77-year climate sequence representative of the ‘recent climate’.








This scenario assumes the full use of existing entitlements and uses seven consecutive climate sequences









analysed.


South-East Gulf rainfall-runoff chapter of the Gulf of Carpentaria division report. These differences are due to differences

in the methods by which the GCMs were ranked and difference in areas that are considered to contribute runoff to the

surface water model. In the South-East Gulf rainfall-runoff chapter of the Gulf of Carpentaria division report the entire

region is considered while a subset of this area is considered here. The scenarios presented in this project may not

eventuate but they encompass consequences that might arise if no management changes are made. Consequently

results from this assessment are designed to highlight pressure points in the system, both now and in the future. This

assessment does not elaborate on what management actions might be taken to address any of these pressure points.

Where management changes to mitigate the effects of climate change have recently been implemented, the impacts of

the changes predicted in this section may be an overestimate.


The Gilbert region is described by the Gilbert IQQM system model (Water Assessment Group, 2006c). The system is

represented in the model by 43 river sections and 182 nodes. Figure 17 is a schematic of the Gilbert IQQM system

model, showing the approximate location of main stream gauges and key demand and storage nodes. A node linkage

diagram for the Gilbert River IQQM model is provided in Appendix 1.

The Miranda Downs gauge on the Gilbert River (917009A) is the most downstream flow monitoring station in the system.

However, this gauge was closed in 1989. The most downstream flow monitoring station which is still open is the

Rockfields gauge on Gilbert River (917001D). The Gilbert River is the principal stream, and major tributaries are:

Copperfield River, Einasliegh River, Etheridge River, Robertson River, Percy River, Little River, McKinnons Creek,

Elizabeth Creek and Agate Creek. Copperfield Dam was constructed on the Copperfield River during 1984 to provide an

assured freshwater supply for the Kidston Gold Mine, which is now closed. The dam has a storage capacity of 21,000 ML.

This model was developed as planning tools and consequently have been set up assuming full use of existing

entitlements. Water use is modelled by 53 nodes as shown in Table 71. There is 1 node for a regulated supply from a

private storage. Other extractions modelled include:

• 6 nodes for unregulated supplies from bedsand storage (there is significant natural storage in the bed sands of

the Gilbert River)

• 35 nodes for unregulated supplies from run-of-river

• 11 nodes for high flow diversions (water harvesting).

There are 16 instream storages in the model. The only major storage is the Copperfield Dam on the Copperfield River.

Details of storages are provided in Table 70. There is a passing flow requirement for Copperfield Dam that up to 1143

ML/day inflow is to be passed though the dam. The degree of regulation metric in Table 70 is the sum of the net

evaporation and controlled released from the dam divided by the total inflows. Controlled releases exclude spillage.

Storages with radial gates and without spillways are not reported in this table (there is only one known storage of this

type in the project area, which is the Kununurra Diversion Dam in the Ord-Bonaparte region). The degree of regulation of

Copperfield Creek Dam under the full use of existing entitlements is moderately high (0.3).


Figure 17. Schematic of the approximate location of gauging stations, main demand nodes and storages for the Gilbert system river

model

Table 70. Storages in the Gilbert system river model

Active storage Mean annual Inflow

Mean annual release

Mean annual net evaporation


GL GL/y

Major reservoirs

Copperfield Dam 18.5 127.2 38.3 2.6 0.3

Region total 18.5 127.2 38.3 2.6 0.3

In Table 71 and the sections that follow, ‘volumetric limit’ is defined as the maximum volume of water that can be

extracted from a river system within this region under the resources operation plan. Unsupplemented water is defined as

surface water that is not sourced from a water storage that is able to regulate or control supply to users.


Table 71. Modelled water use configuration in the Gilbert system river model


Volumetric limit Model notes

GL/y

Town water supply


Agriculture

General Security 13 4.0 No On Farm Storage

Unsupplemented 19 29.9

Mining



Other demands


Total 53 42.136

Model setup

The original Gilbert systems river model and associated IQQM V6.42.2 executable code were obtained from DERM. The

time series rainfall, evaporation and flow inputs to this model for the historical climate time series were set to cover the

historical period from 1 September 1930 to 31 August 2007. The model was run for this period and validated against the

original model run results for the same period. Model setup information for the Gilbert river system model is summarised

in Table 72.


obtained so the same initial storage levels were used for all scenarios. In this project all scenarios are reported for the

77-year period commencing on 1 September 2007. However, the demand simulated by an IQQM model for month n is

dependent upon the simulation results for month n-1. For this reason the initial conditions (i.e. storage levels) are set to

the levels simulated on the 1 August 2007 for all scenarios. The models are then run for 77 years and one month.

A without-development version of the Gilbert model was created by removing all instream storages, all irrigators and

fixed demands.

Table 72. Gilbert river system model setup information


Gilbert IQQM 6.42.2 01/01/1890 30/06/2008

Baseline models

Warm-up period 1/08/2007 31/08/2007

Gilbert IQQM 6.42.2 1/09/2007 31/08/2084

Modifications for Scenario A

Data Data extended by DRNW


Initial storage volumes set to level at 01/08/2007

Copperfield Dam 19GL

Other storages set to level at 01/08/2007








listed based on the different water products in the region. The modelled end-of-system is the Gilbert River at the outflow

to the sea.

Mass balance tables for the 12 reported subcatchments are presented in the following section. The mass balance of

each of these river reaches and the overall mass balance were checked by taking the difference between total inflows,

outflows of the system and change in storage volumes. In all cases the mass balance error was zero. Unattributed fluxes

in Table 73 are the modelled river losses. River losses are estimated from loss relationships that are determined during

calibration of the IQQM model such that flow is conserved between upstream and downstream gauging stations.

Results in Table 73 show that under scenarios Cwet and Cdry, inflows in the Gilbert catchment increase by 32 percent

and decrease by 16 percent respectively. End-of-system flows increase by 34 percent and decrease by 17 percent under

scenarios Cwet and Cdry respectively. There is minimal impact to total diversions (<4 percent) as demands in the

catchment are much smaller than the total inflows.

Table 73. Gilbert system river model mean annual water balance under Scenario A and under scenarios B and C relative to Scenario A

A B Cwet Cmid Cdry

GL/y

Storage volume


Inflows


Subcatchments

Gauged 774.8 -17% 9% 8% -16%

Ungauged 5093.5 -20% 35% 8% -17%

Sub-total 5868.2 -20% 32% 8% -16%

Diversions

Town Water Supply


Agriculture


Unsupplemented 18.7 -2% 0% 1% -4%

Mining



Other Uses


Sub-total 29.0 -1% 0% 0% -3%

Outflows

End-of-system flow 5304.2 -21% 34% 8% -17%

Sub-total 5304.2 -21% 34% 8% -17%

Net evaporation

Storages 5.0 -2% 1% 3% 9%

Sub-total 5.0 -2% 1% 3% 9%

Unattributed fluxes

530.1 -7% 9% 2% -8%



Annual water balances for individual reaches in the Gilber river system model are summarised in Table 74 to Table 85.

Table 74. Gilbert River water balance – gauge 917999

917999 (EoS)


Inflows

Subcatchments

Gauged 3695.1 -16% 23% 7% -15%

Ungauged 1609.1 -33% 60% 11% -24%

Sub-total 5304.2 -21% 34% 8% -17%

Diversions

Agriculture

General Security

Unsupplemented 0.0 -33% 88% 19% -31%

Sub-total 0.0 -33% 88% 19% -31%

Outflows


Sub-total 5304.2 -21% 34% 8% -17%

Unattributed fluxes

0.0 -390% -2735% 101% -831%




Inflows

Subcatchments

Gauged 3695.1 -16% 23% 7% -15%

Ungauged

Sub-total 3695.1 -16% 23% 7% -15%

Diversions

Agriculture

General Security

Unsupplemented 0.0 -100% 0% 100% -67%

Sub-total 0.0 -100% 0% 100% -67%

Outflows


Sub-total 3695.1 -16% 23% 7% -15%

Unattributed fluxes

0.0 -156223% 0% 100% -67%





Inflows

Subcatchments

Gauged 1624.7 -18% 23% 6% -14%

Ungauged 1156.1 -20% 46% 12% -22%

Sub-total 2780.8 -19% 32% 8% -17%

Diversions

Other Uses


Sub-total 0.0 -1% 2% 0% -5%

Outflows


Sub-total 2492.5 -20% 35% 9% -18%

Unattributed fluxes

288.3 -10% 14% 3% -10%




Inflows

Subcatchments

Gauged 175.6 -33% 52% 9% -23%

Ungauged 219.0 -34% 39% 9% -21%

Sub-total 394.5 -34% 44% 9% -22%

Diversions

Other Uses


Sub-total 0.2 -1% 1% 0% -1%

Outflows


Sub-total 382.8 -34% 45% 9% -23%

Unattributed fluxes

11.6 -15% 16% 3% -11%





Inflows

Subcatchments

Gauged 8.7 0% 0% 0% 0%

Ungauged 104.9 -19% 38% 8% -20%

Sub-total 113.6 -17% 35% 8% -19%

Diversions

Agriculture

General Security 0.1 -4% 2% -1% -10%


Mining

High Security 2.0 0% 2% -1% -7%


Sub-total 2.8 -1% 2% -1% -7%

Outflows


Sub-total 108.3 -18% 37% 8% -19%

Net evaporation

Public Storages

Private Storages 0.1 0% -4% 3% 12%

Sub-total 0.1 0% -4% 3% 12%

Unattributed fluxes

2.4 -6% 4% 0% -12%




Inflows

Subcatchments

Gauged 870.8 -8% -1% 3% -5%

Ungauged 342.4 -24% 52% 10% -22%

Sub-total 1213.2 -13% 14% 5% -10%

Diversions

Agriculture


Unsupplemented

Sub-total 1.0 0% 0% -1% -1%

Outflows


Sub-total 1133.7 -13% 14% 5% -10%

Net evaporation

Public Storages

Private Storages 0.3 7% -13% 0% 23%

Sub-total 0.3 7% -13% 0% 23%

Unattributed fluxes

78.3 -9% 12% 3% -9%




GL/y

Storage volume



Inflows

Subcatchments

Gauged 646.7 -10% -2% 3% -7%

Ungauged 279.3 -1% 0% 0% -1%

Sub-total 926.0 -8% -1% 2% -5%

Diversions

Mining


Unsupplemented

Sub-total 4.6 0% 0% 0% 0%

Outflows

End of system flow 870.8 -8% -1% 3% -5%

Sub-total 870.8 -8% -1% 3% -5%

Net evaporation

Public Storage 2.6 -3% 1% 3% 8%

Natural Storage 1.6 -1% 2% 2% 9%

Sub-total 4.2 -2% 1% 3% 8%

Unattributed fluxes

46.4 -1% 0% 0% -1%




Inflows

Subcatchments

Gauged 235.8 0% 0% 0% 0%

Ungauged 260.3 -26% -4% 8% -17%

Sub-total 496.1 -14% -2% 4% -9%

Diversions

Agriculture

General Security


Sub-total 4.3 -1% 0% 0% -2%

Outflows


Sub-total 491.8 -14% -2% 4% -9%

Unattributed fluxes

0.0 -9710% -4193% -10130% -5196%





Inflows

Subcatchments

Gauged

Ungauged 235.8 0% 0% 0% 0%

Sub-total 235.8 0% 0% 0% 0%

Outflows

End of system flow 235.8 0% 0% 0% 0%

Sub-total 235.8 0% 0% 0% 0%

Unattributed fluxes

0.0 0% 0% 0% 0%




Inflows

Subcatchments

Gauged 574.8 -14% -4% 9% -16%

Ungauged 617.3 0% 1% 0% 0%

Sub-total 1192.1 -7% -2% 4% -8%

Diversions

Agriculture



Sub-total 14.3 -2% 0% 1% -4%

Outflows


Sub-total 1114.5 -8% -2% 5% -8%

Net evaporation

Public Storages

Private Storages 0.2 -3% 0% 3% 9%

Sub-total 0.2 -3% 0% 3% 9%

Unattributed fluxes

63.1 -1% 0% 1% -3%





Inflows

Subcatchments

Gauged 166.1 -24% -6% 12% -23%

Ungauged 67.2 -20% -7% 12% -23%

Sub-total 233.3 -23% -6% 12% -23%

Diversions

Sub-total

Outflows


Sub-total 213.1 -24% -7% 13% -24%

Unattributed fluxes

20.3 -10% -3% 4% -15%




Inflows

Subcatchments

Gauged 130.4 -17% -5% 13% -22%

Ungauged 202.1 -1% 0% 1% -1%

Sub-total 332.5 -7% -2% 5% -9%

Diversions

Agriculture

General Security


Sub-total 1.8 -1% 0% 1% -3%

Outflows


Sub-total 310.7 -7% -2% 6% -10%

Net evaporation

Public Storages

Private Storages 0.3 -4% 3% 3% 8%

Sub-total 0.3 -4% 3% 3% 8%

Unattributed fluxes

19.8 -3% -1% 2% -7%


Scaling results


in Figure 18. Donor to target catchment relationships for the Gilbert catchment are illustrated in Figure 18. See Petheram

et al. (2009) for more details. Average monthly scaling factors for streamflow, rainfall and evaporation under scenarios B

and C are listed in Table 86 to Table 97. The catchment number in the scaling factor tables below correspond to the

rainfall-runoff modelling SRN numbers.





Table 86. Gilbert River – Streamflow scaling factors for Scenario B


7101 0.884 0.472 0.663 0.353 0.073 1.339 0.820 0.002 0.000 0.019 4.346 1.655 0.698 0.717

7052 0.805 0.431 0.457 1.434 0.121 1.911 1.133 0.001 0.000 0.000 3.091 1.200 0.617 0.639

7002 0.787 0.400 0.444 0.459 0.123 1.614 1.096 0.003 0.000 2.494 3.378 1.755 0.605 0.587

7007 0.834 0.825 0.484 2.003 0.528 2.807 0.239 0.004 0.002 0.041 0.611 1.292 0.775 0.846

7239 0.892 0.819 0.574 1.274 0.778 0.815 0.584 0.556 0.739 0.981 1.713 1.630 0.841 0.850

7011 0.949 0.788 0.508 1.198 0.788 0.871 0.709 0.618 0.720 0.261 0.554 1.520 0.798 0.816

7015 0.697 0.744 0.437 1.202 0.552 3.022 2.113 0.004 0.000 0.000 0.498 1.343 0.677 0.707

7016 0.660 0.640 0.493 0.779 0.726 0.847 0.697 0.706 0.678 0.710 0.687 1.235 0.667 0.672

7020 0.871 0.768 0.480 1.013 0.815 0.879 0.801 0.806 0.789 0.876 0.980 1.397 0.797 0.771

7023 0.873 0.711 0.857 0.837 0.153 0.995 1.443 0.248 0.156 0.008 3.363 1.774 0.836 0.904

7280 0.786 0.801 0.807 1.079 0.212 0.974 2.999 1.172 0.144 0.001 2.860 1.429 0.824 0.900

7029 0.649 0.843 0.599 1.225 0.422 1.827 1.787 0.004 0.001 0.006 2.071 1.514 0.763 0.781

7030 0.606 0.925 0.696 1.164 0.476 0.768 2.378 2.809 0.768 0.003 2.861 1.653 0.801 0.874

7032 0.617 0.959 0.655 1.026 0.612 1.036 2.539 2.474 0.160 0.012 2.770 1.666 0.810 0.872

7027 0.712 0.880 0.755 1.202 0.364 0.737 3.189 0.507 0.096 0.007 2.625 1.594 0.829 0.904

7287 0.701 0.698 0.505 0.856 0.972 3.583 1.067 1.493 0.687 0.000 0.922 1.524 0.681 0.750

7039 0.802 0.868 0.788 2.075 1.665 2.206 2.925 2.843 0.006 0.181 1.288 2.481 0.919 0.960

7113 0.797 0.413 0.505 0.662 0.075 1.570 0.832 0.002 0.000 0.000 3.417 1.069 0.598 0.612

7001 0.750 0.439 0.555 0.995 0.065 1.645 0.295 0.000 0.000 0.000 4.437 1.157 0.601 0.644

7143 0.782 0.384 0.401 0.476 0.143 1.839 1.149 0.002 0.000 4.724 3.563 1.784 0.588 0.576

7120 0.755 0.364 0.323 0.818 0.202 1.949 1.166 0.010 0.000 4.371 3.924 2.163 0.582 0.572

7122 0.717 0.348 0.284 1.097 0.224 2.106 0.571 0.010 0.000 0.703 3.504 2.469 0.534 0.561

7179 0.740 0.463 0.291 2.282 0.193 3.258 1.665 0.000 0.000 0.000 1.455 1.880 0.581 0.633

7004 0.723 0.525 0.364 1.913 0.223 2.882 1.217 0.000 0.000 0.000 2.705 1.894 0.605 0.663

7187 0.955 0.797 0.546 1.297 0.836 0.979 0.593 0.680 0.670 0.904 2.071 1.654 0.856 0.912

7189 0.957 0.723 0.555 1.143 0.703 0.883 0.612 0.558 0.640 0.246 1.251 1.318 0.787 0.833

7209 0.839 0.725 0.518 2.004 0.448 2.644 0.040 0.133 0.746 0.000 0.662 1.221 0.741 0.815

7261 0.930 0.745 0.554 1.151 0.714 0.825 0.590 0.543 0.648 0.374 1.445 1.434 0.797 0.804

7010 0.971 0.742 0.554 1.103 0.729 0.796 0.624 0.546 0.669 0.259 0.876 1.476 0.798 0.805

7024 0.671 0.798 0.895 1.294 0.393 0.542 1.986 0.825 0.211 0.002 2.471 1.805 0.825 0.912

7291 0.675 0.581 0.461 0.787 0.908 3.123 0.340 0.714 0.615 0.000 0.306 1.357 0.603 0.664

7325 0.768 0.844 0.694 1.848 1.659 2.610 1.754 1.097 0.032 0.046 1.226 2.315 0.858 0.952

7036 0.719 0.873 0.680 1.292 1.052 1.395 1.014 0.896 0.818 0.042 2.280 1.813 0.828 0.892

Table 87. Gilbert River – Rainfall scaling factors for Scenario B


7004 0.996 0.919 0.702 1.769 0.935 1.591 0.561 1.216 0.503 1.464 1.218 1.198 1.019 1.025

7003 0.924 0.887 0.643 1.640 1.029 1.615 0.608 1.290 0.666 1.563 1.165 1.155 0.983 0.990

7001 1.045 0.853 0.756 1.550 0.684 1.687 0.842 1.808 0.499 1.057 1.361 1.102 1.009 1.019

7010 1.041 1.013 0.635 1.368 1.078 1.046 0.536 0.870 0.391 1.154 0.882 1.208 0.988 0.991

7011 1.026 1.006 0.623 1.453 1.126 1.141 0.513 0.841 0.406 1.171 0.813 1.254 0.986 0.991

7024 1.051 0.870 1.010 1.581 0.562 1.911 0.796 1.695 0.541 1.356 1.304 1.195 1.073 1.075

7036 1.029 0.976 0.870 1.612 1.009 2.161 0.724 1.529 0.196 1.279 1.225 1.349 1.085 1.088

Table 88. Gilbert River – Evaporation scaling factors for Scenario B


7004 0.981 0.998 0.999 0.988 1.004 0.995 1.002 0.987 1.015 0.990 0.973 0.962 0.989 0.989

7003 0.970 0.985 0.993 0.981 1.001 0.988 0.999 0.983 1.011 0.985 0.963 0.953 0.982 0.982

7001 0.974 0.990 0.998 0.987 1.002 0.994 1.001 0.988 1.016 0.991 0.971 0.959 0.987 0.987

7010 0.989 1.006 1.001 0.990 1.009 0.994 0.999 0.984 1.013 0.986 0.973 0.966 0.991 0.991

7011 0.992 1.009 1.003 0.992 1.009 0.997 1.001 0.985 1.014 0.989 0.978 0.970 0.994 0.993

7024 0.977 0.999 1.004 0.996 1.004 1.000 1.008 0.993 1.022 0.998 0.980 0.967 0.994 0.994

7036 0.990 1.012 1.012 1.003 1.007 1.006 1.013 0.996 1.026 1.006 0.991 0.976 1.002 1.002


Table 89. Gilbert River – Streamflow scaling factors for Scenario Cwet


7101 0.894 0.960 0.992 0.951 0.893 1.367 1.311 1.032 0.595 0.225 0.408 0.778 0.938 0.934

7052 0.872 0.943 0.995 0.946 0.922 1.365 1.612 0.896 0.630 0.143 0.391 0.716 0.925 0.922

7002 0.898 0.963 0.996 0.942 0.891 1.363 1.335 1.017 0.517 0.105 0.430 0.778 0.939 0.943

7007 1.498 1.522 1.550 1.703 1.726 1.210 1.081 1.055 2.063 1.470 1.402 1.756 1.533 1.543

7239 1.236 1.264 1.184 1.157 1.142 1.042 1.018 1.049 1.113 1.216 1.129 1.266 1.226 1.214

7011 1.439 1.457 1.483 1.383 1.424 1.169 1.200 1.293 1.398 1.398 1.270 1.504 1.453 1.452

7015 1.487 1.494 1.543 1.652 1.731 1.226 1.254 1.344 1.957 1.389 1.346 1.763 1.516 1.520

7016 1.380 1.386 1.429 1.404 1.342 1.297 1.308 1.315 1.313 1.294 1.247 1.450 1.387 1.395

7020 1.446 1.455 1.521 1.490 1.402 1.368 1.378 1.389 1.387 1.373 1.332 1.512 1.461 1.467

7023 0.903 0.979 1.025 1.007 0.980 1.565 2.394 2.920 0.557 0.511 0.489 0.801 0.958 0.952

7280 0.898 0.974 1.028 1.007 0.965 1.568 2.317 3.880 0.277 0.518 0.498 0.818 0.958 0.940

7029 0.885 0.967 1.014 0.958 0.917 1.546 2.064 2.912 0.535 0.524 0.539 0.789 0.943 0.945

7030 0.878 0.948 1.012 0.962 0.880 1.494 1.518 1.255 0.943 0.472 0.541 0.815 0.933 0.917

7032 0.875 0.951 1.010 0.957 0.861 1.529 1.606 1.246 0.193 0.443 0.547 0.796 0.932 0.915

7027 0.891 0.970 1.032 1.004 0.976 1.564 2.100 2.464 0.558 0.489 0.511 0.795 0.955 0.933

7287 1.579 1.571 1.618 1.730 1.874 1.175 1.000 1.441 1.577 1.885 1.470 1.869 1.599 1.608

7039 1.611 1.695 1.707 1.688 1.781 1.328 1.363 0.832 1.615 1.293 1.636 1.942 1.681 1.683

7113 0.884 0.952 0.993 0.930 0.895 1.352 1.475 0.956 0.370 0.050 0.397 0.758 0.931 0.926

7001 0.876 0.937 0.990 0.930 0.894 1.358 1.364 0.807 0.378 0.036 0.369 0.736 0.925 0.915

7143 1.000 1.106 1.097 1.027 0.988 1.064 1.006 0.827 0.574 0.671 0.844 1.016 1.060 1.065

7120 1.006 1.135 1.119 1.051 1.014 1.011 0.922 0.771 0.709 0.810 0.940 1.007 1.079 1.085

7122 0.998 1.123 1.112 1.043 1.001 0.992 0.854 0.609 0.226 0.382 0.926 1.029 1.073 1.075

7179 0.878 0.932 0.995 0.941 0.936 1.366 1.521 1.123 0.729 0.172 0.389 0.715 0.927 0.923

7004 1.002 1.064 1.093 1.063 1.033 1.268 1.184 0.752 0.470 0.613 0.672 1.003 1.050 1.049

7187 1.236 1.268 1.182 1.161 1.146 1.039 1.009 1.030 1.096 1.177 1.124 1.277 1.226 1.228

7189 1.239 1.262 1.180 1.150 1.139 1.032 1.027 1.077 1.137 1.197 1.119 1.269 1.225 1.225

7209 1.535 1.566 1.617 1.824 1.883 1.278 0.872 8.424 1.576 1.495 1.460 1.831 1.583 1.626

7261 1.240 1.264 1.182 1.153 1.143 1.037 1.023 1.067 1.123 1.218 1.129 1.270 1.227 1.214

7010 1.290 1.311 1.251 1.205 1.205 1.061 1.061 1.118 1.189 1.253 1.157 1.323 1.281 1.267

7024 0.906 0.975 1.029 1.003 0.982 1.575 2.828 3.025 0.664 0.515 0.505 0.804 0.960 0.942

7291 1.598 1.569 1.608 1.702 1.819 1.230 0.902 1.177 1.581 1.819 1.453 1.893 1.600 1.611

7325 1.619 1.687 1.718 1.680 1.749 1.419 1.523 0.874 5.028 1.524 1.665 1.929 1.684 1.691

7036 1.113 1.196 1.263 1.235 1.156 1.487 1.308 1.448 1.185 0.752 0.785 1.178 1.185 1.175


Table 90. Gilbert River – Streamflow scaling factors for Scenario Cmid


7101 1.219 1.151 0.995 0.928 0.905 1.040 1.016 0.914 0.580 0.268 0.432 1.220 1.131 1.119

7052 1.218 1.158 0.991 0.898 0.941 1.033 0.989 0.909 0.487 0.187 0.427 1.234 1.128 1.113

7002 1.221 1.153 0.987 0.924 0.894 1.051 1.018 0.888 0.448 0.139 0.457 1.228 1.127 1.119

7007 1.202 1.111 0.988 0.930 0.925 1.081 1.459 1.557 0.441 0.552 0.547 1.203 1.101 1.097

7239 1.156 1.111 0.996 0.963 0.959 1.019 1.078 1.061 0.932 0.695 0.650 1.067 1.076 1.066

7011 1.176 1.106 1.024 0.956 0.972 1.107 1.157 1.106 1.030 0.743 0.639 1.091 1.089 1.088

7015 1.197 1.109 0.979 0.920 0.911 1.104 1.198 1.599 0.401 0.580 0.561 1.239 1.098 1.105

7016 1.165 1.102 0.980 1.016 1.064 1.084 1.084 1.085 1.072 1.039 0.892 1.178 1.087 1.100

7020 1.177 1.114 1.052 1.047 1.089 1.119 1.116 1.109 1.100 1.070 0.913 1.203 1.116 1.122

7023 1.212 1.148 1.011 0.981 0.988 1.164 1.469 1.588 0.514 0.562 0.521 1.154 1.131 1.123

7280 1.201 1.152 1.009 0.979 1.000 1.168 1.542 1.176 0.191 0.566 0.530 1.136 1.127 1.117

7029 1.243 1.126 0.982 0.924 0.920 1.113 1.123 1.640 0.452 0.557 0.559 1.176 1.125 1.122

7030 1.231 1.147 0.982 0.940 0.894 1.109 1.056 1.141 1.108 0.510 0.569 1.153 1.133 1.132

7032 1.233 1.126 0.983 0.928 0.877 1.118 1.106 1.159 0.225 0.481 0.574 1.174 1.125 1.130

7027 1.216 1.151 1.003 0.972 0.996 1.159 1.310 1.518 0.556 0.528 0.541 1.168 1.130 1.128

7287 1.210 1.118 0.986 0.931 0.894 1.109 1.248 1.490 1.076 0.340 0.507 1.310 1.109 1.119

7039 1.232 1.122 0.987 0.945 0.868 1.078 1.082 1.379 0.314 0.498 0.474 1.247 1.109 1.128

7113 1.216 1.162 0.991 0.907 0.911 1.033 0.974 0.851 0.294 0.083 0.427 1.209 1.131 1.120

7001 1.226 1.164 0.998 0.888 0.911 1.004 0.697 0.797 0.469 0.087 0.398 1.248 1.138 1.125

7143 1.234 1.156 0.982 0.915 0.884 1.057 0.991 0.857 0.587 0.201 0.452 1.239 1.131 1.123

7120 1.243 1.151 0.984 0.904 0.900 1.056 0.971 0.861 0.633 0.203 0.466 1.283 1.131 1.125

7122 1.257 1.157 0.987 0.889 0.892 1.027 0.813 0.728 0.572 0.000 0.415 1.294 1.140 1.131

7179 1.237 1.166 0.994 0.900 0.949 1.032 0.852 0.905 0.599 0.224 0.413 1.300 1.135 1.132

7004 1.234 1.165 0.988 0.901 0.918 1.000 0.738 0.771 0.396 0.360 0.389 1.239 1.133 1.126

7187 1.149 1.114 0.997 0.965 0.955 1.028 1.087 1.082 0.890 0.664 0.657 1.013 1.071 1.070

7189 1.164 1.103 0.999 0.959 0.954 1.027 1.073 1.051 0.962 0.678 0.642 1.042 1.075 1.074

7209 1.196 1.118 0.989 0.923 0.921 1.088 1.630 0.295 1.073 0.575 0.544 1.152 1.102 1.090

7261 1.161 1.100 1.001 0.960 0.956 1.023 1.075 1.051 0.952 0.672 0.644 1.054 1.074 1.064

7010 1.161 1.104 0.998 0.960 0.957 1.026 1.063 1.044 0.968 0.707 0.648 1.073 1.075 1.065

7024 1.205 1.157 1.009 0.982 1.004 1.175 1.573 1.630 0.623 0.553 0.531 1.231 1.134 1.131

7291 1.208 1.126 0.985 0.941 0.895 1.100 1.350 1.543 1.075 0.364 0.505 1.329 1.109 1.123

7325 1.222 1.138 0.990 0.947 0.869 1.082 1.052 1.444 0.042 0.484 0.460 1.211 1.112 1.122

7036 1.212 1.120 0.984 0.944 0.870 1.139 1.140 1.107 1.080 0.484 0.531 1.258 1.114 1.117


Table 91. Gilbert River – Streamflow scaling factors for Scenario Cdry


7101 0.828 0.805 0.616 0.507 0.405 0.227 0.199 0.110 0.008 0.046 0.183 0.605 0.751 0.734

7052 0.815 0.794 0.599 0.420 0.465 0.234 0.059 0.105 0.001 0.008 0.188 0.591 0.732 0.716

7002 0.821 0.800 0.615 0.513 0.427 0.242 0.214 0.149 0.015 0.012 0.202 0.607 0.742 0.734

7007 0.840 0.823 0.660 0.513 0.482 0.208 0.022 0.013 0.076 0.330 0.359 0.687 0.771 0.739

7239 0.844 0.838 0.690 0.679 0.655 0.554 0.480 0.555 0.536 0.407 0.455 0.745 0.779 0.759

7011 0.846 0.833 0.694 0.679 0.660 0.558 0.559 0.656 0.654 0.507 0.488 0.759 0.782 0.782

7015 0.827 0.824 0.654 0.528 0.464 0.167 0.029 0.011 0.150 0.338 0.353 0.686 0.767 0.766

7016 0.847 0.832 0.659 0.687 0.770 0.773 0.783 0.789 0.788 0.772 0.668 0.815 0.786 0.796

7020 0.839 0.825 0.650 0.677 0.768 0.770 0.776 0.782 0.781 0.771 0.686 0.808 0.779 0.790

7023 0.821 0.820 0.670 0.613 0.474 0.271 0.107 0.125 0.127 0.284 0.265 0.599 0.770 0.745

7280 0.826 0.825 0.656 0.587 0.493 0.222 0.210 0.757 0.135 0.317 0.290 0.618 0.772 0.745

7029 0.842 0.818 0.643 0.525 0.454 0.221 0.036 0.005 0.008 0.314 0.350 0.670 0.771 0.766

7030 0.834 0.810 0.632 0.535 0.385 0.256 0.033 0.458 0.737 0.256 0.338 0.642 0.766 0.754

7032 0.835 0.807 0.633 0.523 0.388 0.231 0.020 0.511 0.151 0.218 0.348 0.659 0.765 0.756

7027 0.832 0.823 0.661 0.574 0.479 0.213 0.214 0.358 0.194 0.278 0.306 0.618 0.773 0.750

7287 0.828 0.815 0.645 0.517 0.444 0.088 0.003 0.636 0.731 0.157 0.300 0.728 0.762 0.753

7039 0.811 0.776 0.621 0.519 0.427 0.125 0.017 0.043 0.071 0.370 0.286 0.675 0.726 0.737

7113 0.828 0.805 0.602 0.437 0.418 0.187 0.115 0.084 0.003 0.000 0.181 0.604 0.745 0.728

7001 0.822 0.798 0.599 0.399 0.377 0.148 0.104 0.000 0.000 0.000 0.157 0.559 0.742 0.719

7143 0.838 0.813 0.592 0.471 0.408 0.188 0.157 0.104 0.024 0.029 0.199 0.630 0.748 0.738

7120 0.829 0.800 0.584 0.416 0.406 0.217 0.125 0.092 0.007 0.019 0.193 0.618 0.733 0.726

7122 0.830 0.798 0.584 0.373 0.393 0.203 0.090 0.058 0.000 0.000 0.169 0.594 0.736 0.722

7179 0.818 0.795 0.614 0.409 0.503 0.255 0.037 0.119 0.010 0.001 0.206 0.595 0.736 0.728

7004 0.823 0.801 0.617 0.436 0.438 0.212 0.047 0.077 0.006 0.090 0.182 0.594 0.744 0.732

7187 0.841 0.837 0.692 0.679 0.651 0.542 0.466 0.516 0.476 0.404 0.463 0.723 0.775 0.774

7189 0.846 0.839 0.696 0.675 0.652 0.543 0.514 0.618 0.594 0.457 0.461 0.743 0.783 0.779

7209 0.832 0.818 0.652 0.519 0.486 0.215 0.023 0.130 0.730 0.319 0.330 0.653 0.765 0.733

7261 0.843 0.836 0.693 0.678 0.654 0.549 0.487 0.595 0.573 0.417 0.451 0.741 0.779 0.759

7010 0.849 0.842 0.700 0.685 0.658 0.549 0.509 0.611 0.601 0.470 0.471 0.759 0.786 0.767

7024 0.833 0.825 0.658 0.595 0.467 0.271 0.135 0.404 0.246 0.302 0.302 0.634 0.774 0.749

7291 0.825 0.818 0.648 0.530 0.454 0.061 0.002 0.377 0.729 0.163 0.313 0.730 0.762 0.755

7325 0.806 0.780 0.620 0.500 0.412 0.093 0.016 0.053 0.013 0.287 0.308 0.657 0.726 0.722

7036 0.828 0.801 0.631 0.522 0.394 0.241 0.068 0.193 0.726 0.233 0.308 0.704 0.755 0.745

Table 92. Gilbert River – Rainfall scaling factors for Scenario Cwet


7004 1.061 1.062 1.027 1.021 1.023 1.115 1.116 1.119 0.930 0.925 0.927 1.104 1.047 1.048

7003 1.079 1.087 1.028 1.025 1.023 1.015 1.015 1.016 1.006 1.010 1.011 1.151 1.068 1.069

7001 1.026 1.029 0.997 0.992 0.993 1.192 1.193 1.193 0.878 0.874 0.872 1.093 1.017 1.020

7010 1.132 1.132 1.103 1.100 1.097 0.965 0.964 0.963 1.005 1.020 1.030 1.140 1.111 1.109

7011 1.191 1.190 1.192 1.144 1.150 0.969 0.969 0.968 1.076 1.078 1.080 1.204 1.174 1.174

7024 1.027 1.035 0.997 0.996 0.994 1.192 1.193 1.193 0.873 0.872 0.873 1.077 1.019 1.021

7036 1.091 1.095 1.076 1.058 1.030 1.122 1.112 1.127 0.943 0.945 0.944 1.122 1.080 1.080


Table 93. Gilbert River – Rainfall scaling factors for Scenario Cmid


7004 1.043 1.036 0.989 0.988 0.990 1.073 1.072 1.073 0.862 0.858 0.864 1.005 1.005 1.007

7003 1.047 1.032 0.990 0.987 0.989 1.073 1.072 1.073 0.859 0.855 0.865 1.001 1.004 1.005

7001 1.045 1.041 0.990 0.985 0.988 1.073 1.073 1.072 0.863 0.859 0.863 0.992 1.004 1.004

7010 1.038 1.038 0.991 0.985 0.982 1.073 1.072 1.072 0.846 0.855 0.866 1.008 1.006 1.005

7011 1.043 1.035 0.989 0.956 0.960 1.156 1.157 1.159 0.825 0.829 0.841 1.011 1.006 1.007

7024 1.038 1.033 0.989 0.990 0.989 1.073 1.072 1.072 0.853 0.857 0.865 1.019 1.006 1.007

7036 1.039 1.028 0.990 0.985 0.984 1.073 1.073 1.072 0.857 0.861 0.863 1.025 1.009 1.010

Table 94. Gilbert River – Rainfall scaling factors for Scenario Cdry


7004 0.959 0.956 0.845 0.865 0.867 0.734 0.735 0.733 0.827 0.829 0.824 0.964 0.915 0.915

7003 0.958 0.955 0.844 0.861 0.875 0.734 0.734 0.734 0.830 0.831 0.823 0.968 0.911 0.911

7001 0.958 0.957 0.844 0.867 0.873 0.734 0.734 0.735 0.829 0.830 0.823 0.965 0.915 0.912

7010 0.958 0.955 0.844 0.873 0.867 0.734 0.735 0.735 0.836 0.831 0.823 0.969 0.917 0.915

7011 0.958 0.953 0.844 0.877 0.866 0.734 0.734 0.736 0.835 0.832 0.823 0.972 0.918 0.919

7024 0.955 0.957 0.848 0.858 0.862 0.734 0.736 0.736 0.830 0.827 0.820 0.967 0.916 0.916

7036 0.957 0.956 0.846 0.862 0.873 0.734 0.734 0.734 0.831 0.827 0.824 0.967 0.921 0.921

Table 95. Gilbert River – Evaporation scaling factors for Scenario Cwet


7004 1.019 1.019 1.028 1.028 1.028 1.039 1.039 1.039 1.024 1.024 1.025 1.019 1.026 1.026

7003 1.016 1.016 1.029 1.029 1.029 1.038 1.038 1.038 1.021 1.021 1.021 1.016 1.024 1.024

7001 1.022 1.022 1.028 1.028 1.028 1.038 1.038 1.038 1.026 1.026 1.026 1.022 1.027 1.027

7010 1.011 1.011 1.030 1.030 1.030 1.042 1.042 1.042 1.021 1.021 1.021 1.011 1.024 1.024

7011 1.015 1.015 1.029 1.029 1.029 1.039 1.039 1.039 1.025 1.025 1.025 1.015 1.026 1.026

7024 1.022 1.022 1.029 1.029 1.029 1.039 1.039 1.039 1.027 1.027 1.027 1.022 1.028 1.028

7036 1.020 1.020 1.030 1.030 1.030 1.039 1.039 1.039 1.027 1.027 1.027 1.020 1.028 1.028

Table 96. Gilbert River – Evaporation scaling factors for Scenario Cmid


7004 1.011 1.011 1.028 1.028 1.028 1.025 1.025 1.025 1.029 1.029 1.029 1.011 1.023 1.023

7003 1.011 1.011 1.028 1.028 1.028 1.025 1.025 1.025 1.029 1.029 1.029 1.011 1.023 1.023

7001 1.011 1.011 1.029 1.029 1.029 1.026 1.026 1.025 1.029 1.029 1.029 1.011 1.023 1.023

7010 1.011 1.011 1.028 1.028 1.028 1.025 1.025 1.025 1.029 1.029 1.029 1.011 1.023 1.023

7011 1.009 1.009 1.027 1.027 1.027 1.025 1.025 1.025 1.027 1.027 1.027 1.009 1.021 1.022

7024 1.011 1.011 1.029 1.029 1.029 1.026 1.026 1.026 1.029 1.029 1.029 1.011 1.023 1.023

7036 1.011 1.011 1.029 1.029 1.029 1.027 1.027 1.027 1.029 1.029 1.029 1.011 1.023 1.024

Table 97. Gilbert River – Evaporation scaling factors for Scenario Cdry


7004 1.038 1.038 1.048 1.048 1.048 1.044 1.044 1.044 1.039 1.039 1.039 1.038 1.041 1.041

7003 1.038 1.038 1.048 1.048 1.048 1.044 1.044 1.044 1.039 1.039 1.039 1.038 1.041 1.041

7001 1.037 1.037 1.048 1.048 1.048 1.043 1.043 1.043 1.039 1.039 1.039 1.037 1.041 1.041

7010 1.038 1.038 1.048 1.048 1.048 1.043 1.043 1.043 1.039 1.039 1.039 1.038 1.041 1.041

7011 1.038 1.038 1.048 1.048 1.048 1.044 1.044 1.044 1.039 1.039 1.039 1.038 1.041 1.041

7024 1.038 1.038 1.048 1.048 1.048 1.044 1.044 1.044 1.039 1.039 1.039 1.038 1.042 1.042

7036 1.038 1.038 1.048 1.048 1.048 1.044 1.044 1.044 1.039 1.039 1.039 1.038 1.042 1.042


3.7 Mitchell

Model overview

The Mitchell region is described by the Mitchell river system model using the IQQM program (version 6.42.2). The

Mitchell model was setup by the Department of Environment and Resource Management (DERM) to support the

Queensland Water Resource Planning Process. Results from this model for the period from January 1913 to December

1995 were used to establish the water sharing rules in the Gulf (draft) Resource Operations Plan (DNRW, 2008). The

level of development represented by the model is based on the full use of existing entitlements.


the period 1 January 1890 to 30 June 2008. Results for the Northern Australia Sustainable Yields Project are presented

over 77-year time sequences for the common modelling period 1 September 2007 to 31 August 2084. The results

presented in DNRW reports (e.g. Water Assessment Group, 2004; DNRW, 2008) may differ from numbers published in

this report due to the different modelling period and different initial conditions.

In the Northern Australia Sustainable Yields Project the river system modelling for the Mitchell region consists of ten

scenarios:

• Scenario A – historical climate and full use of existing entitlements



the water accounted for in the resource operations plan, but the licences are interim or not allocated as yet. The

period of analysis commences on 1 September 2007 and streamflow metrics are produced by modelling the 77-

year historical climate sequence between 1 September 2007 and 31 August 2084. This scenario is used as a

baseline for comparison with all other scenarios.

• Scenario AN – historical climate and without-development









considered to be negligible. This scenario uses seven consecutive 11-year climate sequences between 1

September 1996 and 31 August 2007 to generate a 77-year climate sequence representative of the ‘recent

climate’.







• Scenario B – recent climate and full use of existing developments









No future development information was available for the Leichhardt River catchment. Hence Scenario D was not

analysed.


The Mitchell region is described by the Mitchell systems model (Water Assessment Group, 2004). The system is

represented in the model by 27 river sections and 124 nodes. Figure 19 is a schematic of the Mitchell IQQM simulation

model, showing the approximate location of main stream gauges and key demand and storage nodes. A node linkage

diagram for the Mitchell River IQQM model is shown in Appendix 1.

The model does not extend over the whole Mitchell River basin, but excludes the upper catchment areas of the Mitchell

and Walsh rivers which are included in the Barron Water Resources Plan area, and these catchments are modelled in

the Barron River IQQM. The upstream limits of the model are the Walsh River at Flatrock streamflow recorder and the

Mitchell River at AMTD 601.2 km. The simulated outflows from the Barron River IQQM at these locations become the

inflows to the Mitchell River IQQM. Inflows include inter-valley transfer from the Barron River for irrigation diversions in

the upper reaches of the Walsh and Mitchell rivers. The net average annual diversion from the Barron system is 6.2

GL/year (diversions less transfers).

The downstream limit of the model is the mouth of the Mitchell River. The stream gauging station at Koolatah (919009) is

the most downstream location at which flow records are available. This station monitors flow from approximately two-

thirds of the river basin. The Mitchell River is the principal stream and major tributaries of the Mitchell River are the

Palmer, Walsh, Lynd and Tate rivers.

Grazing is the predominant land use over the basin. Some irrigated agriculture is practised in the upper reaches of the

Walsh and Mitchell rivers, where irrigation supplies are obtained from the Mareeba-Dimbulah Water Supply Scheme.

Within the area modelled the main consumptive water uses are small-scale irrigation and small mines. Communities and

towns, including Chillagoe and Mount Molloy, add to the overall consumption of water in the area.

There are no state-owned storages or water supply schemes in the modelled area. One major storage, Southedge Dam,

and five smaller instream storages, are represented by the model. Details for Southedge Dam and the five smaller

instream storages are provided in Table 98. There are no passing flow requirements for storages. The degree of

regulation metric presented in Table 98 is the sum of the net evaporation and controlled releases from the dam divided

by the total inflows. Controlled releases exclude spillage. Storages with radial gates and without spillways are not

reported in this table (there is only one known storage of this type in the project area, which is the Kununurra Diversion

Dam in the Ord-Bonaparte region). The degree of regulation of Southedge Dam for the full use of existing entitlements

(0.53) would be relatively high.

Table 98. Storages in the river system model

Major reservoirs Active storage Average annual Inflow




GL GL/y

Southedge Dam 122.6 88.7 20.0 26.9 0.53

Other storages * 11.7 2077.0 1.8 0.00

Region total 134.26 2165.65 20.00 28.72 0.02

This model was developed as a planning tool and consequently has been set up assuming full use of existing

entitlements. A consequence of this is that the model does not simulate current levels of development. Water use is

modelled by 27 nodes that are categorised into different users in Table 99. Diversions are modelled from:

1. one node that is for a regulated supply from a private storage

2. 21 nodes for unregulated supplies from run-of-river flows

3. five nodes for high flow diversion (water harvesting).


Figure 19. Schematic of the approximate location of gauging stations, main demand nodes and storages for the Mitchell river system

model

In Table 99 and the sections that follow, ‘volumetric limit’ is defined as the maximum volume of water that can be

extracted from a river system within this region under the resources operation plan. Unsupplemented water is defined as

surface water that is not sourced from a water storage that is able to regulate or control supply to users.

Table 99. Modelled water use configuration


Volumetric limit Planted area

Model notes

GL/y ha

Unsupplemented Agriculture 12 31.056 3,084

Unsupplemented (Town Water Supply) 2 0.192 Fixed demand

Unsupplemented (Mining) 4 10.368 Fixed demand

High Security (Other Uses) 1 20 Fixed demand

Unsupplemented (Other Uses) 8 15.374 Fixed demand

Sub-total 27 76.99 3084


Model setup

The original Mitchell river model and associated IQQM V6.42.2 executable code were obtained from DERM. The time

series rainfall, evaporation and flow inputs to this model for the historical climate time series were set to cover the

reporting period 1 September 1930 to 31 August 2007. The model was run for the reporting period and the results were

validated against results from the original model over the same period. Model setup information for the Mitchell river

system model is summarised in Table 100.


obtained so the same initial storage levels need to be used for all scenarios. In this project all scenarios are reported for

the 77-year period commencing on 1 September 2007. However, the demand simulated by an IQQM model for month n

is dependent upon the simulation results for month n-1. For this reason the initial conditions (i.e. storage levels) are set to

the levels simulated on the 1 August 2007 for all scenarios. The models are then run for 77 years and one month.

A without-development version of the Mitchell model was created by removing all instream storages, all irrigators and

fixed demands. Flow and climate input files to the Barron IQQM model were not modified for climate change scenarios.

Hence, inflows to the Mitchell IQQM from the Barron IQQM were only sourced for Scenario A. However, inflows to the

Mitchell IQQM from the Barron IQQM were modified for scenarios B and C during the process of applying the Mitchell

subcatchment constant monthly scaling factors to all inflows.

Table 100. Mitchell system river model setup information


Mitchell IQQM 6.42.2 01/01/1890 20/08/2008

Connection

Barron IQQM Inflows from model to Walsh River at Flatrock gauge

Inflows from model to Mitchell River at AMTD 601.2

Baseline models

Warm up period 1/08/2007 31/08/2007

Mitchell IQQM 6.42.2 1/09/2007 31/08/2084

Connection

Modifications

Data Data extended by DNRW


Initial storage volume Southedge 109.3GL

Initial storage volume for other storages set to level at 01/08/2007






gauged inflows include flows from the Barron IQQM and other inflows that are derived to achieve a mass balance

between mainstream gauges. Diversions are listed based on the different water products in the region. End-of-system

flows are shown for the Mitchell River at modelled end-of-system which includes inflows from other creeks below the

gauge at Koolatah.

The overall mass balance was checked by taking the difference between inflows, diversions, outflows of the system and

change in storage volume. The mass balance error was zero. Unattributed fluxes in Table 101 are the modelled river

losses. River losses are estimated from loss relationships that are determined during calibration of the IQQM model such

that flow is conserved between upstream and downstream gauging stations.

Results in Table 101 show that under scenarios Cwet and Cdry, inflows in the Mitchell valley increase by 49 percent and

decrease by 26 percent respectively. End-of-system flows increase by 51 percent and decrease by 26 percent under


scenarios Cwet and Cdry respectively. However, there is minimal impact to total diversions (<2 percent) as demands in

the valley are much smaller than the total inflows.

Under Scenario B (Table 101), inflows increase by 3 percent (relative to Scenario A) for gauged subcatchments while

inflows increase by 18 percent (relative to Scenario A) for ungauged subcatchments. This large difference is due to the

larger increase in rainfall under Scenario B on the (largely ungauged) lower reaches of the Mitchell catchment compared

to the upper reaches, where the majority of the gauging stations are located.

Table 101. Mitchell system river model average annual water balance under scenarios A, B and C

A B Cwet Cmid Cdry

GL/y

Storage volume



Inflows

Subcatchments

Gauged 2878.7 3% 44% -5% -26%

Ungauged 10675.8 18% 51% -6% -26%

Sub-total 13554.6 15% 49% -6% -26%

Diversions

Agriculture


Mining

Unsupplemented 10.1 0% 1% -2% 0%

Town Water Supply


Other Uses



Sub-total 75.0 0% 1% -1% -1%

Outflows


Sub-total 12023.2 16% 51% -6% -26%

Net evaporation

Southedge 26.9 -5% -9% 4% -2%

Other Storages 1.8 -4% -10% 11% 5%

Sub-total 28.7 -5% -9% 5% -1%

Unattributed fluxes

1427.6 7% 35% -3% -23%



Annual water balances for individual reaches in the Mitchell river system model are summarised in Table 102 to Table

118.

Table 102. Mitchell River water balance – gauge 919005


GL/y

Storage volume



Inflows

Subcatchments

Gauged

Ungauged 391.4 4% 19% -3% -28%

Sub-total 391.4 4% 19% -3% -28%

Diversions

Agriculture


Other Uses



Sub-total 22.2 0% 0% 0% 0%

Outflows


Sub-total 340.9 5% 23% -4% -32%

Net evaporation

Southedge 26.9 -5% -9% 4% -2%

Other Storages 1.2 -4% -10% 5% 9%

Sub-total 28.2 -5% -9% 4% -1%

Unattributed fluxes

0.1 1% 1% 0% 0%




GL/y

Storage volume

Change over period


Inflows

Subcatchments

Gauged

Ungauged 742.7 3% 22% -6% -30%

Sub-total 742.7 3% 22% -6% -30%

Diversions

Agriculture


Sub-total 0.6 2% 1% -1% -11%

Outflows


Sub-total 742.0 3% 22% -6% -30%

Unattributed fluxes

0.0 158% -79% 30% 25%



GL/y

Storage volume

Change over period


Inflows

Subcatchments

Gauged 84.4 -1% 21% -8% -27%

Ungauged

Sub-total 84.4 -1% 21% -8% -27%

Diversions

Agriculture


Other Uses

High Security


Sub-total 1.9 0% 0% 0% -1%

Outflows


Sub-total 82.5 -1% 21% -8% -28%

Unattributed fluxes

0.0 -108% -40% -46% -58%





Inflows

Subcatchments

Gauged 205.3 -2% 20% -8% -30%

Ungauged

Sub-total 205.3 -2% 20% -8% -30%

Diversions

Agriculture


Sub-total 0.1 0% 0% 0% 0%

Outflows


Sub-total 205.2 -2% 20% -8% -30%

Unattributed fluxes

0.0 -463% -151% -151% 463%




Inflows

Subcatchments

Gauged 340.7 6% 26% -5% -33%

Ungauged

Sub-total 340.7 6% 26% -5% -33%

Diversions

Sub-total 0.0 0% 0% 0% 0%

Outflows


Sub-total 340.7 6% 26% -5% -33%

Unattributed fluxes

0.0 -185% -231% -194% -199%





Inflows

Subcatchments

Gauged 1082.7 4% 23% -6% -31%

Ungauged 699.2 5% 56% -6% -25%

Sub-total 1782.0 4% 36% -6% -29%

Diversions

Agriculture


Mining


Sub-total 4.8 1% 3% -1% -6%

Outflows


Sub-total 1745.5 4% 37% -6% -29%

Unattributed fluxes

31.6 2% 3% -1% -8%




Inflows

Subcatchments

Gauged 199.3 1% 50% -3% -22%

Ungauged

Sub-total 199.3 1% 50% -3% -22%

Diversions

Sub-total

Outflows


Sub-total 199.3 1% 50% -3% -22%

Unattributed fluxes





Inflows

Subcatchments

Gauged

Ungauged 644.4 -6% 22% -1% -34%

Sub-total 644.4 -6% 22% -1% -34%

Diversions

Sub-total

Outflows


Sub-total 644.4 -6% 22% -1% -34%

Unattributed fluxes




Inflows

Subcatchments

Gauged 644.4 -6% 22% -1% -34%

Ungauged 319.9 0% 43% 0% -22%

Sub-total 964.2 -4% 29% 0% -30%

Diversions

Mining


Sub-total 4.9 0% 2% 0% -3%

Outflows


Sub-total 909.5 -4% 30% -1% -30%

Unattributed fluxes

49.8 -1% 15% 0% -20%




Inflows

Subcatchments

Gauged 1108.8 -3% 34% -1% -29%

Ungauged 335.6 0% 48% -3% -21%

Sub-total 1444.5 -3% 37% -1% -27%

Diversions

Sub-total

Outflows


Sub-total 1277.1 -2% 35% -1% -26%

Unattributed fluxes

167.3 -4% 53% -3% -34%





Inflows

Subcatchments

Gauged 3022.7 1% 36% -4% -28%

Ungauged 595.4 9% 54% -5% -22%

Sub-total 3618.1 3% 39% -4% -27%

Diversions

Agriculture


Sub-total 19.8 0% 1% 0% -2%

Outflows


Sub-total 3404.3 3% 40% -4% -28%

Unattributed fluxes

194.0 3% 22% -2% -20%

Table 113. Mitchell River water balance – 919002



Inflows

Subcatchments

Gauged 134.3 -21% 40% 1% -24%

Ungauged

Sub-total 134.3 -21% 40% 1% -24%

Diversions

Sub-total

Outflows


Sub-total 134.3 -21% 40% 1% -24%

Unattributed fluxes




Inflows

Subcatchments

Gauged 134.3 -21% 40% 1% -24%

Ungauged 644.9 -19% 43% 0% -23%

Sub-total 779.3 -19% 42% 0% -23%

Diversions

Agriculture


Mining


Town Water Supply


Other Uses





Sub-total 5.1 -1% 1% 0% -1%

Outflows


Sub-total 768.9 -19% 43% 0% -23%

Unattributed fluxes

5.2 -10% 20% 1% -15%



GL/y

Storage volume



Inflows

Subcatchments

Gauged 485.6 -13% 40% 1% -23%

Ungauged

Sub-total 485.6 -13% 40% 1% -23%

Diversions

Sub-total

Outflows


Sub-total 485.3 -13% 40% 1% -23%

Net evaporation

Southedge

Other Storages 0.2 -1% -8% 3% 12%

Sub-total 0.2 -1% -8% 3% 12%

Unattributed fluxes

0.0 -81% -5% -223% 59%




GL/y

Storage volume



Inflows

Subcatchments

Gauged 1429.1 12% 54% -7% -26%

Ungauged

Sub-total 1429.1 12% 54% -7% -26%

Diversions

Agriculture


Mining


Town Water Supply


Other Uses



Sub-total 15.4 0% 1% 0% -2%

Outflows


Sub-total 1413.4 12% 55% -7% -26%

Net evaporation

Southedge

Other Storages 0.3 -6% -14% 6% 17%

Sub-total 0.3 -6% -14% 6% 17%

Unattributed fluxes

0.0 -146% -145% -158% -173%




Inflows

Subcatchments

Gauged 6071.9 1% 44% -4% -26%

Ungauged 1172.1 21% 54% -6% -25%

Sub-total 7244.0 4% 45% -4% -26%

Diversions

Sub-total

Outflows


Sub-total 6894.2 4% 47% -5% -27%

Unattributed fluxes

349.8 3% 16% 0% -15%





Inflows

Subcatchments

Gauged 6696.8 4% 41% -4% -25%

Ungauged 5758.9 30% 56% -8% -26%

Sub-total 12643.2 16% 51% -6% -26%

Diversions

Sub-total

Outflows


Sub-total 12023.2 16% 51% -6% -26%

Unattributed fluxes

620.0 15% 44% -5% -25%


Scaling results


in Figure 20. Donor to target catchment relationships are illustrated in Figure 20. See Petheram et al. (2009) for more

details. Average monthly scaling factors for streamflow, rainfall and evaporation under scenarios B and C are listed in

Table 119 to Table 130. The catchment numbers in the scaling factor tables below refer to the SRN numbers used for

the rainfall-runoff modelling.





Table 119. Mitchell River – Streamflow scaling factors for Scenario B


9010 0.587 0.990 0.877 1.056 1.035 0.965 1.017 0.985 0.988 1.060 0.883 1.057 0.907 0.883

9200 0.662 1.028 0.862 1.389 1.369 0.844 0.996 0.942 0.981 0.879 1.483 1.565 0.944 0.954

9091 1.359 1.192 1.031 0.934 1.314 1.037 1.097 1.027 1.065 1.580 1.944 1.657 1.197 1.188

9100 1.355 1.056 1.051 0.858 1.336 1.003 1.243 0.750 0.969 1.818 1.678 1.317 1.120 1.137

9071 1.269 1.032 0.940 0.609 1.586 1.019 0.449 0.057 0.011 2.116 1.549 1.325 1.081 1.073

9013 0.670 1.097 0.963 1.217 1.018 0.980 1.037 1.000 1.128 1.270 0.944 1.391 1.002 0.988

9380 0.804 1.150 1.053 1.494 1.718 0.194 0.312 0.016 1.904 3.647 0.691 1.617 1.067 1.076

9360 0.805 0.955 1.053 1.017 0.895 0.886 0.938 0.805 0.993 1.140 1.109 1.315 0.980 0.982

9340 0.664 1.041 1.067 1.045 0.991 0.918 0.958 0.895 1.164 1.463 0.900 1.253 0.989 0.985

9300 0.866 1.093 1.129 1.353 1.057 0.981 1.020 0.939 1.369 2.146 1.141 1.704 1.123 1.125

9207 1.183 0.877 0.738 0.515 1.090 0.622 0.280 0.118 0.015 1.548 1.281 1.616 0.972 0.918

9240 1.162 0.941 0.804 0.657 1.198 0.563 0.307 0.036 0.007 2.743 1.086 1.604 1.006 1.013

9202 1.106 0.927 0.802 0.926 0.863 0.543 0.351 0.158 0.019 2.713 0.993 1.577 0.989 0.946

9280 0.972 0.778 0.647 0.917 0.728 0.376 0.246 0.207 0.038 3.678 1.656 1.715 0.865 0.867

9256 0.982 0.773 0.498 0.973 0.835 0.795 0.767 0.671 0.752 0.626 1.115 1.816 0.816 0.830

9250 0.873 0.742 0.529 1.186 0.795 0.743 0.603 0.561 0.839 1.818 2.084 1.890 0.802 0.838

9096 1.562 1.106 1.333 1.379 3.645 2.029 4.728 3.636 5.385 6.664 4.803 2.203 1.305 1.360

9016 0.734 1.090 1.009 1.280 1.018 0.978 1.036 0.985 1.205 1.412 0.954 1.465 1.032 1.020

9021 0.751 1.097 1.005 1.187 1.113 1.043 1.093 1.054 1.110 1.281 1.017 1.377 1.030 1.016

9030 0.728 1.152 1.102 1.171 1.124 1.048 1.092 1.057 1.178 1.386 0.903 1.329 1.074 1.057

9043 0.752 1.126 1.113 1.199 1.066 0.979 1.037 0.928 1.289 1.673 0.902 1.427 1.070 1.062

9050 0.709 1.111 1.104 1.009 1.035 1.028 1.050 1.018 1.060 1.104 1.003 1.197 1.037 1.022

9063 1.133 1.082 0.911 0.856 1.024 0.859 0.987 0.816 0.851 1.039 1.091 1.477 1.045 1.041

9320 0.787 1.100 1.045 1.346 0.922 0.918 1.006 0.926 1.394 1.774 1.167 1.724 1.070 1.079

9304 0.739 1.060 1.064 1.302 0.932 0.912 0.968 0.947 1.293 1.969 1.337 1.787 1.055 1.066

9309 0.807 1.140 1.124 1.385 1.104 1.018 1.063 1.018 1.271 1.758 0.950 1.652 1.114 1.123

Table 120. Mitchell River – Rainfall scaling factors for Scenario B


9091 1.123 1.064 0.887 1.145 0.824 1.386 0.822 0.832 0.249 1.614 1.174 1.229 1.091 1.090

9100 1.153 1.033 0.947 1.000 0.946 0.954 0.909 1.038 0.697 1.236 1.082 1.125 1.062 1.063

9071 1.125 1.023 0.869 0.947 0.899 1.237 0.795 0.774 0.491 1.312 1.147 1.148 1.051 1.050

9063 1.083 1.030 0.966 0.942 0.937 0.994 1.239 0.780 0.799 1.240 1.015 1.202 1.056 1.052

9063 1.083 1.030 0.966 0.942 0.937 0.994 1.239 0.780 0.799 1.240 1.015 1.202 1.056 1.053

9360 0.895 1.019 1.050 0.954 0.658 0.750 0.889 0.904 1.038 1.266 1.057 1.201 1.002 1.003

9340 0.814 1.110 1.023 1.007 0.760 0.781 0.869 0.997 1.275 1.477 1.060 1.228 1.020 1.020

9309 0.882 1.176 1.012 1.273 0.829 0.953 1.022 1.255 1.573 1.924 1.165 1.411 1.109 1.116

9207 1.084 0.959 0.808 0.932 0.864 1.197 0.779 0.604 0.281 1.443 1.126 1.257 1.031 1.030

9240 1.086 0.977 0.871 0.959 0.925 1.122 1.051 0.656 0.457 1.399 1.074 1.238 1.043 1.042

9202 1.045 1.011 0.865 0.945 1.141 1.068 0.970 1.061 0.439 1.545 1.030 1.262 1.047 1.045

9280 0.990 0.967 0.761 1.128 1.066 0.978 0.816 1.062 0.472 1.647 1.044 1.283 1.011 1.011

9256 1.022 0.961 0.674 1.310 1.082 1.150 0.582 0.717 0.278 1.485 0.930 1.291 0.996 0.998

9250 0.973 0.961 0.679 1.428 1.178 0.809 0.570 0.963 0.639 1.539 1.036 1.245 0.992 0.996

9096 1.159 1.051 1.007 1.121 1.054 0.824 0.785 1.167 0.205 1.666 1.282 1.152 1.107 1.106

Table 121. Mitchell River – Evaporation scaling factors for Scenario B


9010 0.999 1.013 0.999 0.996 1.025 0.994 1.005 0.998 1.020 1.000 0.986 0.983 1.001 1.001

9010 0.999 1.013 0.999 0.996 1.025 0.994 1.005 0.998 1.020 1.000 0.986 0.983 1.001 1.001


Table 122. Mitchell River – Streamflow scaling factors for Scenario Cwet


9010 1.250 1.232 1.147 1.111 1.093 1.117 1.110 1.121 1.126 1.145 1.226 1.316 1.186 1.198

9200 1.274 1.243 1.156 1.149 1.165 1.257 1.169 1.211 1.181 1.235 1.396 1.372 1.224 1.225

9091 1.559 1.564 1.505 1.471 1.390 1.349 1.370 1.374 1.398 1.429 1.210 1.612 1.537 1.533

9100 1.580 1.564 1.508 1.451 1.432 1.350 1.343 1.323 1.335 1.343 1.317 1.637 1.540 1.543

9071 1.507 1.547 1.568 1.542 1.565 1.555 1.710 1.485 1.382 1.423 1.219 1.544 1.538 1.540

9013 1.248 1.227 1.146 1.111 1.089 1.123 1.115 1.128 1.133 1.153 1.231 1.303 1.181 1.200

9380 1.307 1.261 1.187 1.178 1.277 1.499 1.738 1.484 1.129 1.400 1.260 1.439 1.255 1.253

9360 1.289 1.215 1.239 1.164 1.148 1.122 1.117 1.111 1.081 1.058 0.899 1.215 1.203 1.213

9340 1.288 1.216 1.236 1.148 1.102 1.107 1.113 1.124 1.114 1.087 0.872 1.140 1.210 1.193

9300 1.282 1.175 1.227 1.157 1.115 1.095 1.096 1.100 1.079 1.020 0.847 1.158 1.190 1.193

9207 1.483 1.498 1.484 1.458 1.478 1.638 1.791 1.965 1.272 1.179 1.061 1.466 1.480 1.482

9240 1.491 1.517 1.504 1.504 1.528 1.591 1.829 1.644 1.163 1.163 1.086 1.498 1.500 1.502

9202 1.458 1.440 1.421 1.409 1.419 1.615 1.812 1.541 1.140 1.013 0.996 1.416 1.430 1.434

9280 1.437 1.398 1.378 1.361 1.357 1.572 1.840 2.029 1.268 1.142 1.024 1.403 1.397 1.397

9256 1.447 1.472 1.372 1.351 1.337 1.367 1.397 1.391 1.358 1.195 0.966 1.471 1.428 1.430

9250 1.422 1.447 1.350 1.328 1.317 1.345 1.390 1.408 1.313 1.248 0.995 1.452 1.402 1.406

9096 1.729 1.570 1.455 1.454 1.561 1.608 1.458 1.629 2.243 1.669 1.586 2.269 1.558 1.565

9016 1.242 1.219 1.142 1.110 1.089 1.130 1.120 1.135 1.135 1.157 1.235 1.295 1.177 1.194

9021 1.268 1.241 1.149 1.112 1.097 1.122 1.118 1.133 1.138 1.160 1.240 1.329 1.192 1.211

9030 1.284 1.251 1.216 1.137 1.110 1.120 1.124 1.135 1.140 1.140 1.041 1.172 1.219 1.233

9043 1.303 1.225 1.238 1.152 1.116 1.111 1.115 1.121 1.113 1.083 0.883 1.151 1.216 1.233

9050 1.302 1.280 1.247 1.154 1.146 1.136 1.133 1.131 1.127 1.123 1.017 1.189 1.234 1.258

9063 1.624 1.583 1.476 1.373 1.434 1.386 1.396 1.414 1.422 1.437 1.254 1.703 1.551 1.545

9320 1.288 1.216 1.229 1.149 1.115 1.102 1.109 1.120 1.110 1.074 0.893 1.192 1.207 1.207

9304 1.278 1.186 1.216 1.152 1.105 1.103 1.112 1.126 1.117 1.059 0.882 1.149 1.194 1.193

9309 1.278 1.218 1.223 1.143 1.108 1.109 1.117 1.129 1.129 1.100 0.937 1.139 1.207 1.202

Table 123. Mitchell River – Streamflow scaling factors for Scenario Cmid


9010 0.878 0.886 1.152 1.166 1.078 1.068 1.046 1.048 1.045 1.035 0.891 0.828 1.013 0.995

9200 0.874 0.886 1.185 1.301 1.324 1.211 1.033 1.059 1.013 0.944 0.651 0.814 0.994 0.998

9091 0.844 0.836 1.134 1.292 1.214 1.077 1.055 1.045 1.012 0.879 0.765 0.810 0.946 0.968

9100 0.812 0.806 1.106 1.235 1.212 1.098 1.052 1.076 0.965 0.827 0.700 0.775 0.930 0.920

9071 0.862 0.856 1.153 1.309 1.446 1.383 1.431 1.352 0.696 0.629 0.768 0.837 0.954 0.958

9013 0.889 0.891 1.154 1.183 1.098 1.084 1.060 1.062 1.050 1.034 0.904 0.835 1.024 0.991

9380 0.848 0.859 1.178 1.338 1.594 1.579 1.630 1.413 0.693 0.470 0.616 0.786 0.960 0.976

9360 0.785 0.785 1.019 1.051 1.045 1.017 1.016 1.031 0.986 0.967 0.867 0.804 0.922 0.912

9340 0.786 0.793 1.044 1.075 1.026 1.013 1.007 1.002 0.975 0.951 0.844 0.779 0.921 0.913

9300 0.803 0.803 1.054 1.093 1.079 1.046 1.049 1.054 0.995 0.948 0.852 0.797 0.941 0.938

9207 0.898 0.897 1.207 1.365 1.520 1.352 1.264 1.209 0.784 0.752 0.839 0.887 0.991 1.024

9240 0.890 0.881 1.194 1.355 1.531 1.371 1.304 1.147 0.825 0.734 0.813 0.869 0.979 0.968

9202 0.914 0.914 1.237 1.399 1.549 1.326 1.244 1.115 0.856 0.759 0.846 0.903 1.015 1.052

9280 0.908 0.913 1.228 1.366 1.493 1.359 1.340 1.363 0.833 0.690 0.818 0.897 1.012 1.024

9256 0.902 0.897 1.231 1.324 1.334 1.132 1.085 1.054 1.011 0.920 0.851 0.879 1.004 0.994

9250 0.904 0.897 1.228 1.298 1.331 1.149 1.093 1.073 0.985 0.881 0.822 0.874 1.008 0.991

9096 0.780 0.797 1.108 1.277 1.347 1.096 1.127 1.165 1.127 0.437 0.511 0.670 0.932 0.946

9016 0.894 0.893 1.157 1.189 1.109 1.097 1.069 1.074 1.054 1.028 0.884 0.842 1.029 0.994

9021 0.878 0.884 1.151 1.159 1.073 1.067 1.048 1.054 1.044 1.024 0.886 0.821 1.011 0.982

9030 0.796 0.806 1.062 1.071 1.006 1.003 0.991 0.992 0.979 0.964 0.873 0.767 0.931 0.901

9043 0.780 0.787 1.043 1.070 1.026 1.013 1.008 1.013 0.981 0.954 0.850 0.776 0.921 0.886

9050 0.776 0.770 1.013 1.003 0.978 0.968 0.963 0.969 0.957 0.950 0.891 0.776 0.898 0.865

9063 0.823 0.821 1.176 1.208 1.213 1.105 1.050 1.068 0.976 0.928 0.717 0.791 0.946 0.958

9320 0.795 0.792 1.054 1.087 1.059 1.029 1.018 1.014 0.990 0.961 0.863 0.786 0.941 0.931

9304 0.812 0.809 1.057 1.095 1.065 1.034 1.019 1.009 0.986 0.949 0.865 0.801 0.943 0.940

9309 0.794 0.798 1.051 1.078 1.027 1.011 0.999 0.993 0.977 0.955 0.878 0.785 0.929 0.928


Table 124. Mitchell River – Streamflow scaling factors Scenario Cdry


9010 0.691 0.711 0.668 0.729 0.783 0.768 0.781 0.770 0.757 0.722 0.506 0.546 0.697 0.690

9200 0.676 0.707 0.637 0.634 0.615 0.644 0.724 0.700 0.714 0.628 0.229 0.503 0.663 0.662

9091 0.791 0.793 0.694 0.657 0.728 0.766 0.767 0.757 0.765 0.571 0.374 0.699 0.751 0.743

9100 0.776 0.778 0.713 0.671 0.713 0.727 0.737 0.664 0.654 0.467 0.280 0.665 0.742 0.741

9071 0.828 0.825 0.722 0.665 0.620 0.502 0.311 0.242 0.233 0.195 0.380 0.756 0.781 0.780

9013 0.700 0.720 0.677 0.731 0.790 0.772 0.783 0.775 0.754 0.717 0.543 0.568 0.706 0.698

9380 0.675 0.707 0.646 0.588 0.457 0.269 0.191 0.345 0.128 0.021 0.155 0.520 0.668 0.664

9360 0.653 0.687 0.747 0.746 0.760 0.764 0.759 0.740 0.716 0.666 0.424 0.554 0.703 0.701

9340 0.685 0.710 0.768 0.758 0.785 0.774 0.772 0.771 0.740 0.681 0.394 0.568 0.727 0.712

9300 0.708 0.730 0.776 0.766 0.756 0.746 0.728 0.711 0.673 0.587 0.364 0.576 0.729 0.731

9207 0.840 0.839 0.703 0.646 0.571 0.379 0.262 0.196 0.246 0.269 0.471 0.797 0.788 0.776

9240 0.839 0.829 0.708 0.655 0.541 0.369 0.266 0.212 0.309 0.294 0.422 0.782 0.784 0.791

9202 0.834 0.836 0.682 0.640 0.550 0.327 0.267 0.237 0.302 0.298 0.467 0.797 0.777 0.769

9280 0.819 0.828 0.678 0.645 0.596 0.367 0.290 0.201 0.183 0.189 0.418 0.768 0.768 0.765

9256 0.832 0.824 0.681 0.673 0.656 0.560 0.594 0.677 0.672 0.545 0.471 0.752 0.773 0.777

9250 0.823 0.819 0.678 0.667 0.657 0.549 0.509 0.570 0.546 0.485 0.433 0.724 0.762 0.768

9096 0.735 0.777 0.720 0.640 0.579 0.246 0.328 0.322 0.202 0.071 0.058 0.542 0.737 0.727

9016 0.706 0.727 0.680 0.730 0.787 0.770 0.779 0.771 0.747 0.697 0.522 0.564 0.708 0.702

9021 0.680 0.706 0.664 0.730 0.780 0.763 0.773 0.760 0.744 0.700 0.508 0.546 0.692 0.683

9030 0.677 0.700 0.732 0.754 0.799 0.785 0.791 0.778 0.758 0.716 0.527 0.545 0.716 0.703

9043 0.679 0.704 0.758 0.756 0.786 0.771 0.767 0.752 0.731 0.673 0.403 0.554 0.721 0.712

9050 0.664 0.669 0.732 0.755 0.773 0.774 0.778 0.766 0.756 0.735 0.574 0.556 0.707 0.689

9063 0.775 0.778 0.705 0.711 0.727 0.716 0.759 0.677 0.660 0.613 0.303 0.684 0.746 0.743

9320 0.704 0.717 0.769 0.773 0.783 0.773 0.782 0.779 0.751 0.684 0.436 0.580 0.737 0.732

9304 0.728 0.741 0.783 0.776 0.772 0.761 0.772 0.775 0.743 0.652 0.420 0.607 0.750 0.746

9309 0.712 0.728 0.771 0.769 0.794 0.779 0.788 0.784 0.762 0.703 0.479 0.591 0.743 0.738

Table 125. Mitchell River – Rainfall scaling factors for Scenario Cwet


9091 1.179 1.181 1.156 1.131 1.124 1.098 1.092 1.091 1.090 1.093 1.078 1.175 1.163 1.164

9100 1.173 1.176 1.159 1.117 1.107 1.059 1.054 1.055 1.122 1.139 1.116 1.165 1.160 1.160

9071 1.178 1.181 1.159 1.120 1.134 1.081 1.077 1.079 1.103 1.122 1.095 1.175 1.164 1.165

9063 1.170 1.180 1.157 1.104 1.118 1.078 1.073 1.079 1.095 1.119 1.087 1.162 1.158 1.156

9063 1.170 1.180 1.157 1.104 1.118 1.078 1.073 1.079 1.095 1.119 1.087 1.162 1.158 1.156

9360 1.077 1.065 1.101 1.040 1.016 0.999 1.002 1.004 1.066 1.041 0.982 1.050 1.056 1.057

9340 1.078 1.077 1.105 1.026 0.970 1.004 1.001 0.998 1.078 1.041 0.980 1.020 1.058 1.059

9309 1.074 1.078 1.101 1.027 0.970 1.006 0.997 0.999 1.091 1.047 0.977 1.018 1.060 1.057

9207 1.180 1.180 1.149 1.138 1.142 1.124 1.119 1.121 1.033 1.040 1.030 1.179 1.159 1.160

9240 1.179 1.180 1.152 1.128 1.139 1.115 1.114 1.118 1.043 1.056 1.043 1.178 1.160 1.160

9202 1.171 1.171 1.135 1.134 1.129 1.136 1.135 1.135 1.006 1.007 1.004 1.170 1.146 1.147

9280 1.163 1.162 1.127 1.120 1.112 1.130 1.127 1.128 1.013 1.013 1.010 1.161 1.139 1.139

9256 1.180 1.180 1.144 1.146 1.142 1.141 1.141 1.141 1.002 1.001 0.997 1.181 1.155 1.156

9250 1.170 1.169 1.135 1.132 1.127 1.135 1.134 1.134 1.010 1.008 1.004 1.170 1.143 1.144

9096 1.177 1.184 1.161 1.129 1.103 1.063 1.065 1.065 1.140 1.136 1.126 1.168 1.167 1.168


Table 126. Mitchell River – Rainfall scaling factors for Scenario Cmid


9091 0.961 0.961 1.188 1.192 1.196 1.040 1.043 1.045 0.950 0.945 0.937 0.961 1.007 1.010

9100 0.945 0.946 1.167 1.163 1.159 1.060 1.060 1.060 0.938 0.940 0.926 0.944 0.997 0.999

9071 0.956 0.956 1.181 1.181 1.182 1.050 1.050 1.052 0.939 0.945 0.932 0.955 1.002 1.005

9063 0.953 0.953 1.175 1.178 1.177 1.050 1.049 1.050 0.941 0.949 0.932 0.953 1.001 1.009

9063 0.953 0.953 1.175 1.178 1.177 1.050 1.049 1.050 0.941 0.949 0.932 0.953 1.001 1.008

9360 0.914 0.911 1.095 1.096 1.097 1.067 1.066 1.068 0.964 0.955 0.941 0.910 0.978 0.979

9340 0.913 0.913 1.095 1.096 1.097 1.067 1.067 1.067 0.966 0.955 0.941 0.907 0.978 0.979

9309 0.912 0.913 1.095 1.097 1.098 1.067 1.067 1.067 0.964 0.955 0.942 0.909 0.979 0.983

9207 0.975 0.975 1.206 1.222 1.217 1.026 1.028 1.028 0.953 0.953 0.950 0.977 1.020 1.024

9240 0.971 0.970 1.199 1.219 1.208 1.031 1.029 1.031 0.951 0.955 0.946 0.972 1.015 1.019

9202 0.982 0.982 1.211 1.241 1.228 1.023 1.020 1.024 0.959 0.957 0.954 0.984 1.028 1.031

9280 0.979 0.979 1.205 1.230 1.229 1.032 1.026 1.030 0.959 0.955 0.950 0.982 1.025 1.027

9256 0.984 0.983 1.217 1.244 1.240 1.017 1.015 1.016 0.964 0.962 0.958 0.991 1.029 1.032

9250 0.981 0.980 1.209 1.236 1.241 1.024 1.021 1.024 0.961 0.958 0.953 0.987 1.028 1.030

9096 0.948 0.949 1.171 1.168 1.166 1.059 1.059 1.059 0.937 0.934 0.926 0.944 0.999 1.001

Table 127. Mitchell River – Rainfall scaling factors for Scenario Cdry


9091 0.952 0.951 0.871 0.896 0.896 0.759 0.764 0.764 0.765 0.756 0.756 0.957 0.917 0.918

9100 0.946 0.945 0.886 0.897 0.904 0.785 0.787 0.788 0.738 0.722 0.719 0.948 0.909 0.910

9071 0.951 0.950 0.877 0.898 0.899 0.770 0.771 0.772 0.745 0.736 0.742 0.954 0.915 0.916

9063 0.948 0.944 0.877 0.901 0.899 0.773 0.774 0.772 0.754 0.747 0.742 0.953 0.912 0.910

9063 0.948 0.944 0.877 0.901 0.899 0.773 0.774 0.772 0.754 0.747 0.742 0.953 0.912 0.910

9360 0.889 0.892 0.892 0.878 0.875 0.832 0.832 0.831 0.846 0.806 0.729 0.896 0.870 0.871

9340 0.889 0.889 0.892 0.877 0.865 0.831 0.832 0.832 0.860 0.806 0.727 0.902 0.874 0.875

9309 0.890 0.889 0.890 0.880 0.872 0.831 0.833 0.832 0.861 0.809 0.727 0.902 0.877 0.876

9207 0.955 0.955 0.856 0.884 0.872 0.744 0.749 0.745 0.802 0.801 0.796 0.960 0.920 0.920

9240 0.955 0.953 0.860 0.896 0.870 0.750 0.752 0.746 0.795 0.795 0.784 0.959 0.918 0.918

9202 0.952 0.952 0.843 0.892 0.869 0.739 0.743 0.738 0.823 0.824 0.811 0.959 0.914 0.915

9280 0.947 0.944 0.843 0.891 0.890 0.744 0.747 0.746 0.816 0.814 0.800 0.958 0.910 0.910

9256 0.958 0.953 0.843 0.885 0.868 0.733 0.736 0.735 0.840 0.836 0.822 0.972 0.920 0.920

9250 0.953 0.947 0.841 0.885 0.888 0.739 0.742 0.740 0.827 0.823 0.810 0.964 0.911 0.911

9096 0.949 0.947 0.886 0.902 0.914 0.780 0.780 0.780 0.718 0.718 0.717 0.952 0.916 0.918

Table 128. Mitchell River – Evaporation scaling factors for Scenario Cwet


9010 1.000 1.000 1.010 1.010 1.010 1.037 1.037 1.037 1.015 1.015 1.015 1.000 1.014 1.014

9010 1.000 1.000 1.010 1.010 1.010 1.037 1.037 1.037 1.015 1.015 1.015 1.000 1.014 1.014

Table 129. Mitchell River – Evaporation scaling factors for Scenario Cmid


9010 1.043 1.043 1.015 1.015 1.015 1.022 1.022 1.022 1.025 1.025 1.025 1.043 1.028 1.027

9010 1.043 1.043 1.015 1.015 1.015 1.022 1.022 1.022 1.025 1.025 1.025 1.043 1.028 1.027

Table 130. Mitchell River – Evaporation scaling factors for Scenario Cdry


9010 1.040 1.040 1.042 1.042 1.042 1.036 1.036 1.036 1.030 1.030 1.030 1.040 1.037 1.037

9010 1.040 1.040 1.042 1.042 1.042 1.036 1.036 1.036 1.030 1.030 1.030 1.040 1.037 1.037


4 Summary

Six river system models were used in this project; a MIKE BASIN model for the lower Ord River catchment, a simple

single node reservoir model for the Darwin River Dam, and Integrated Quantity and Quality Models for the Leichhardt,

Flinders, Gilbert and Mitchell river catchments. In addition to the river system models a coupled groundwater-hydraulic

model (technically not a river system model) was used for the Daly river catchment. The description and setup of the

Daly model is detailed in an accompanying report. For the river system models and the Daly river model a variety of

metrics have been reported, including water availability, level of consumptive use and storage behaviour of spills. A

collective summary of the key results is provided below. Detailed results are provided in the river modelling section of the

regional chapers in the drainage division reports.

Water availability

Figure 21 compares water availability in six river modelling catchments under the without development scenarios A, B

and C. All six rivers are gaining rivers, that is their mean annual flow increases towards the coast and is highest at the

end-of-system. It should be noted, however, that not all of the water at the most downstream gauge is accessible for

consumptive use.

Figure 21. Transect of total mean annual river flow in the Ord, Daly, Leichhardt, Flinders, Gilbert and Mitchell river systems under

scenarios AN, BN and CN

In the Leichhardt, Gilbert and Mitchell, large ungauged flows occur downstream of the last gauge. This is particularly

evident in the Mitchell where ungauged flows below the last gauge constitute almost 50 percent of all inflows. In all


catchments, the mean annual flow under Scenario CNmid is similar to Scenario AN. In the Gilbert and Flinders rivers,

mean annual flow along the transect are less under Scenario BN than under Scenario AN. In the Ord and Daly rivers,

however, mean annual flow is considerably higher under Scenario BN than under Scenario AN or Scenario CNwet (i.e.

top of CN range). Hence, extreme caution should be exercised if future management decisions are to be based on

hydrological data from the recent climate only.

Water balance

Table 131 compares the mean annual water balance for five river system models under Scenario A. Ungauged inflows

constitute the majority of flow in all catchments. Unattributed fluxes are highest in the Mitchell, 1428 GL/yr, however, the

Flinders River has the highest unattributed fluxes expressed as a percentage of the total inflows (i.e. 29 percent).

Unattributed fluxes in the Flinders river catchment may in part be due to large transmission losses that are likely to occur

within the catchment. Water usage within these river systems is low (typically less than several percent of the total

inflows) relative to river systems in the Murray Darling Basin. It should be noted, however, that the IQQM models (i.e. for

the Leichhardt, Flinders, Gilbert and Mitchell) were setup assuming the full use of existing entitlements. A consequence

of this is that these models do not simulate current levels of development.

Table 131. River system models mean annual water balance under Scenario A

Ord Leichhardt Flinders Gilbert Mitchell

GL/y

Storage volume


Inflows

Subcatchments

Gauged 4832.2 233.0 535.8 774.8 2878.7

Ungauged 115.8 1807.7 2404.2 5093.5 10675.8

Sub-total 4948.1 2040.7 2940.0 5868.2 13554.6

Diversions

Agriculture

General Security 348.3 7.8 13.1 3.0 0.0

Unsupplemented 0.0 23.6 86.7 18.7 29.8

Mining

High Security 0.0 29.4 0.0 6.6 0.0

Unsupplemented 0.0 3.8 0.0 0.4 10.1

Town Water Supply

High Security 0.0 32.3 3.3 0.0 0.0


Other Uses

High Security 0.0 13.9 2.5 0.0 20.0

General Security 0.0 0.0 0.0 0.2 0.0


Sub-total 348.3 110.8 107.0 29.0 75.0

Outflows

End of system flow 3593.8 1784.6 1981.9 5304.2 12023.2

Sub-total 3593.8 1784.6 1981.9 5304.2 12023.2

Net evaporation

Major Storages 992.9 71.6 10.0 5.0 26.9

Other Storages 17.9 1.2 0.0 0.0 1.8


Ord Leichhardt Flinders Gilbert Mitchell

Sub-total 1010.7 72.8 10.0 5.0 28.7

Unattributed fluxes

GL/y -10.6 72.4 841.0 530.1 1427.6

Percentage of inflows -0.2% 3.5% 28.6% 9.0% 10.5%

Level of use

In the river systems of the Gulf of Carpentaria, the level of use tends to be highest in the upper reaches of the

catchments, which is also where the water availability is lowest. Nevertheless, with the exception of the Leichhardt, the

level of use does not exceed 10 percent at any point within these systems (Figure 22). In the Leichhardt, which supplies

water to the mining town of Mount Isa and surrounding mines, the level of use exceeds 25 percent under Scenario A at

stream gauge 913012.

Figure 22. Transect of relative level of surface water use in the Leichhardt, Flinders, Gilbert and Mitchell river systems under scenarios

A and C


Mean monthly flows

Figure 23 shows the strong seasonality of flow at the end-of-system gauges reflecting the wet and dry seasons. With the

exception of the Ord, there are minimal changes in end-of-system flows compared to without-development conditions

under all scenarios. In the Ord, wet season flows have been moderated considerably due to the Ord River Dam.

Conversely dry season flows have increased substantially. It should be noted in the figures below, the GCMs were

ranked on an annual basis not a monthly basis, which is why In the case of the Leichhardt Cmid exceeds the Crange for

two months of the year.

Figure 23. Mean monthly flow for the Ord, Daly, Leichhardt, Flinders, Gilbert and Mitchell end-of-systems under scenarios AN, A and C


Daily flow exceedance

Flow exceedance curves for the Ord, Daly, Leichhardt, Flinders, Gilbert and Mitchell are shown in Figure 24. Under

climate scenarios there is not a large impact to low flows at the end-of-system. In the Daly, Flinders, Gilbert and Mitchell

there is little difference between the daily flow under Scenario AN and Scenario A. In the Leichhardt the number of flow

days decreases slightly under Scenario A. In the Ord, daily flows have completely changed following development of the

Ord River Dam. Where once the system was ephemeral it is now perennial with a dry season baseflow exceeding 1

GL/day.

Figure 24. Daily flow exceedance curves for the Ord, Daly, Leichhardt, Flinders, Gilbert and Mitchell river systems. Note the vertical

scale bar for the Ord and Daly are GL and the vertical scale bars for the Leichhardt, Flinders, Gilbert and Mitchell are ML.


Non-river modelling regions

In those regions where information on infrastructure, water demand, water management and sharing rules or future

development were not provided no river modelling assessment was undertaken. The development of river system

models for these regions is not warranted unless future development occurs.


5 References

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Appendix 1

The following pages show node linkage diagrams for the Leichhardt, Flinders, Gilbert and Mitchell river catchments.

Source: Produced at the Indooroopilly Sciences Centre by the Spatial Information and Mapping Group, Natural Resource

Information Management, Natural Resource Sciences, Department of Natural Resources and Mines. © The State of

Queensland (Department of Natural Resources and Mines) 2004 – 2007.





Documents

River modelling for Northern Australia · The authors gratefully acknowledge the assistance provided by the Western Australian, Northern Territory and Queensland governments throughout