River modelling for Northern Australia · The authors gratefully acknowledge the assistance...
Transcript of River modelling for Northern Australia · The authors gratefully acknowledge the assistance...
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.
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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.
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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 18. 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 ................................................................75
Figure 19. Schematic of the approximate location of gauging stations, main demand nodes and storages for the Mitchell river system model ..........................................................................................................................................................................83
Figure 20. 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 ................................................................95
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>
© CSIRO 2009 River modelling for northern Australia ▪ 3
Figure 2. AWRC surface water management areas. River modelling catchment shown by red outline
4 ▪ River modelling for northern Australia © CSIRO 2009
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).
© CSIRO 2009 River modelling for northern Australia ▪ 5
Figure 3. Relief map, major rivers, NASY drainage divisions and AWRC river basins
6 ▪ River modelling for northern Australia © CSIRO 2009
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).
© CSIRO 2009 River modelling for northern Australia ▪ 7
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)
8 ▪ River modelling for northern Australia © CSIRO 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.
© CSIRO 2009 River modelling for northern Australia ▪ 9
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
10 ▪ River modelling for northern Australia © CSIRO 2009
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
© CSIRO 2009 River modelling for northern Australia ▪ 11
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.
12 ▪ River modelling for northern Australia © CSIRO 2009
∑
∑
=
=
=
=
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.
© CSIRO 2009 River modelling for northern Australia ▪ 13
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
14 ▪ River modelling for northern Australia © CSIRO 2009
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.
© CSIRO 2009 River modelling for northern Australia ▪ 15
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.
16 ▪ River modelling for northern Australia © CSIRO 2009
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.
© CSIRO 2009 River modelling for northern Australia ▪ 17
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.
18 ▪ River modelling for northern Australia © CSIRO 2009
Figure 9. Schematic diagram of MIKE BASIN model for the lower Ord system
© CSIRO 2009 River modelling for northern Australia ▪ 19
Table 1. Major storage in the Ord river system model
Active storage Average annual Inflow
Average annual release
Average annual net evaporation
Degree of regulation
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.
20 ▪ River modelling for northern Australia © CSIRO 2009
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).
© CSIRO 2009 River modelling for northern Australia ▪ 21
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).
22 ▪ River modelling for northern Australia © CSIRO 2009
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.
© CSIRO 2009 River modelling for northern Australia ▪ 23
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.
24 ▪ River modelling for northern Australia © CSIRO 2009
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.
© CSIRO 2009 River modelling for northern Australia ▪ 25
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.
• 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. Hence this scenario used the same inflow sequence as Scenario A.
• Scenario BN – recent climate and without-development
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.
• Scenario CN – future climate and without-development
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
26 ▪ River modelling for northern Australia © CSIRO 2009
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.
River model description
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 release
Average annual
diversion
Average annual net evaporation
Degree of regulation
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.
© CSIRO 2009 River modelling for northern Australia ▪ 27
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
River system water balance – whole of system
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
GL/y percent change from Scenario A
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.
28 ▪ River modelling for northern Australia © CSIRO 2009
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
Catchment J F M A M J J A S O N D Annual Monthly annual
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
Catchment J F M A M J J A S O N D Annual Monthly annual
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
Catchment J F M A M J J A S O N D Annual Monthly annual
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
Catchment J F M A M J J A S O N D Annual Monthly annual
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
Catchment J F M A M J J A S O N D Annual Monthly annual
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
Catchment J F M A M J J A S O N D Annual Monthly annual
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
Catchment J F M A M J J A S O N D Annual Monthly annual
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
Catchment J F M A M J J A S O N D Annual Monthly annual
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
© CSIRO 2009 River modelling for northern Australia ▪ 29
Table 19. Darwin River Dam – Evaporation scaling factors for Scenario Cwet
Catchment J F M A M J J A S O N D Annual Monthly annual
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
Catchment J F M A M J J A S O N D Annual Monthly annual
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
Catchment J F M A M J J A S O N D Annual Monthly annual
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
30 ▪ River modelling for northern Australia © CSIRO 2009
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.
• Scenario AN – historical climate sequence and without-development
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.
• Scenario BN – recent climate and without-development
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 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 CN – future climate and without-development
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. 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.
© CSIRO 2009 River modelling for northern Australia ▪ 31
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.
River model description
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.
32 ▪ River modelling for northern Australia © CSIRO 2009
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
Average annual release
Average annual net evaporation
Degree of regulation
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.
© CSIRO 2009 River modelling for northern Australia ▪ 33
Table 23. Modelled water use configuration in the Leichhardt river system model
Water users Number of nodes
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
High Security 3 34.4 Fixed Demand
Other Demands
High Security 4 14.3 Fixed Demand
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
Model setup information Version Start date End date
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
34 ▪ River modelling for northern Australia © CSIRO 2009
River system water balance – whole of system
The mass balance table (Table 25) shows volumetric components under 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.
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.
© CSIRO 2009 River modelling for northern Australia ▪ 35
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
GL/y percent change from Scenario A
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%
Unsupplemented 3.8 4% 3% 1% -4%
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%
36 ▪ River modelling for northern Australia © CSIRO 2009
River system reach water balance
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
GL/y percent change from Scenario A
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%
Unsupplemented 6.3 3% 0% 2% -4%
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%
© CSIRO 2009 River modelling for northern Australia ▪ 37
Table 27. Leichardt River water balance – gauge 913003
913003 A B Cwet Cmid Cdry
GL/y
Storage volume
Change over period 0.0 0.0 0.0 0.0 0.0
GL/y percent change from Scenario A
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%
Unsupplemented 1.9 5% 2% 1% -3%
Town Water Supply
High Security 0.1 1% 1% 0% -3%
Other Uses
High Security 0.0 0% 0% 0% 0%
Sub-total 4.0 2% 1% 1% -3%
Outflows
End of system flow 198.6 74% 35% 19% -23%
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%
Table 28. Leichardt River water balance – gauge 913007
913007 A B Cwet Cmid Cdry
GL/y percent change from Scenario A
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%
Unsupplemented 17.3 6% 3% 2% -5%
Sub-total 24.0 4% 2% 2% -4%
Outflows
End of system flow 1225.0 68% 32% 21% -25%
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%
38 ▪ River modelling for northern Australia © CSIRO 2009
Table 29. Leichardt River water balance – gauge 913004
913004 A B Cwet Cmid Cdry
GL/y percent change from Scenario A
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
High Security 0.4 0% 0% 0% 0%
Unsupplemented 1.9 4% 4% 1% -6%
Sub-total 2.3 4% 3% 1% -5%
Outflows
End of system flow 239.0 139% 56% 30% -30%
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%
Table 30. Leichardt River water balance – gauge 913012
913012 A B Cwet Cmid Cdry
GL/y
Storage volume
Change over period 0.0 0.2 0.2 0.1 -0.2
GL/y percent change from Scenario A
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
End of system flow 155.3 166% 66% 36% -34%
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%
© CSIRO 2009 River modelling for northern Australia ▪ 39
Table 31. Leichardt River water balance – gauge 913014
913014 A B Cwet Cmid Cdry
GL/y
Storage volume
Change over period 0.0 0.5 0.3 0.2 -0.3
GL/y percent change from Scenario A
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%
Unsupplemented 0.0 7% 9% 5% -12%
Mining
High Security 12.2 12% 9% 6% -12%
Unsupplemented
Town Water Supply
High Security 10.7 14% 10% 6% -13%
Other Uses
High Security 2.1 9% 6% 3% -9%
Sub-total 25.1 13% 9% 6% -12%
Outflows
End of system flow 144.5 126% 51% 29% -26%
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%
40 ▪ River modelling for northern Australia © CSIRO 2009
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.
© CSIRO 2009 River modelling for northern Australia ▪ 41
Table 32. Leichardt River – Streamflow scaling factors for Scenario B
Catchment J F M A M J J A S O N D Annual Monthly annual
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
Catchment J F M A M J J A S O N D Annual Monthly annual
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
Catchment J F M A M J J A S O N D Annual Monthly annual
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
42 ▪ River modelling for northern Australia © CSIRO 2009
Table 35. Leichardt River – Streamflow scaling factors for Scenario Cwet
Catchment J F M A M J J A S O N D Annual Monthly annual
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
Catchment J F M A M J J A S O N D Annual Monthly annual
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
© CSIRO 2009 River modelling for northern Australia ▪ 43
Table 37. Leichardt River – Streamflow scaling factors for Scenario Cdry
Catchment J F M A M J J A S O N D Annual Monthly annual
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
Catchment J F M A M J J A S O N D Annual Monthly annual
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
Catchment J F M A M J J A S O N D Annual Monthly annual
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
Catchment J F M A M J J A S O N D Annual Monthly annual
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
Catchment J F M A M J J A S O N D Annual Monthly annual
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
44 ▪ River modelling for northern Australia © CSIRO 2009
Table 42. Leichardt River – Evaporation scaling factors for Scenario Cmid
Catchment J F M A M J J A S O N D Annual Monthly annual
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
Catchment J F M A M J J A S O N D Annual Monthly annual
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
© CSIRO 2009 River modelling for northern Australia ▪ 45
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.
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 Flinders catchment consists 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.
• Scenario AN – historical climate sequence and without-development
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.
• Scenario BN – recent climate and without-development
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 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 CN – future climate and without-development
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. 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.
46 ▪ River modelling for northern Australia © CSIRO 2009
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 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.
River model description
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.
© CSIRO 2009 River modelling for northern Australia ▪ 47
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
Average annual release
Average annual net evaporation
Degree of regulation
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.
48 ▪ River modelling for northern Australia © CSIRO 2009
Table 45. Modelled water use configuration in the Flinders river system model
Water users Number of nodes
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
High Security 2 2.5 Fixed demand
Unsupplemented 7 1.5 Fixed demand
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
Model setup information Version Start date End date
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
© CSIRO 2009 River modelling for northern Australia ▪ 49
River system water balance – whole of system
The mass balance table (Table 47) shows volumetric components under 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.
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 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
Change over period 0.0 0.0 0.0 0.0 0.0
GL/y percent change from Scenario A
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
High Security 2.5 0% 0% 0% 0%
Unsupplemented 1.4 1% 2% -2% -4%
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%
50 ▪ River modelling for northern Australia © CSIRO 2009
River system reach water balance
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
Change over period 0.0 0.0 0.0 0.0 0.0
GL/y percent change from Scenario A
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
High Security 0.0 0% 0% 0% -1%
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%
Table 49. Flinders River water balance – gauge 915003
915003 A B Cwet Cmid Cdry
GL/y percent change from Scenario A
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
Unsupplemented 0.4 -1% 9% -1% -9%
Sub-total 0.4 -1% 9% -1% -9%
Outflows
End of system flow 1937.9 -7% 33% 2% -26%
Sub-total 1937.9 -7% 33% 2% -26%
Net evaporation
Storages
Sub-total
Unattributed fluxes
661.9 -8% 39% 4% -29%
© CSIRO 2009 River modelling for northern Australia ▪ 51
Table 50. Flinders River water balance – gauge 915209
915209 A B Cwet Cmid Cdry
GL/y
Storage volume
Change over period 0.0 0.0 0.0 0.0 0.0
GL/y percent change from Scenario A
Inflows
Subcatchments
Gauged
Ungauged 71.1 74% 39% 8% -25%
Sub-total 71.1 74% 39% 8% -25%
Diversions
Other Uses
High Security 2.5 0% 0% 0% 0%
Unsupplemented
Sub-total 2.5 0% 0% 0% 0%
Outflows
End of system flow 62.6 83% 44% 8% -28%
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%
Table 51. Flinders River water balance – gauge 915212
915212 A B Cwet Cmid Cdry
GL/y
Storage volume
Change over period 0.0 0.0 0.0 0.0 0.0
GL/y percent change from Scenario A
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
General Security 0.2 -1% 5% 0% -6%
Unsupplemented 21.6 2% 4% 1% -6%
Sub-total 21.8 2% 4% 1% -6%
Outflows
End of system flow 1163.1 17% 38% 8% -26%
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%
52 ▪ River modelling for northern Australia © CSIRO 2009
Table 52. Flinders River water balance – gauge 915203
915203 A B Cwet Cmid Cdry
GL/y
Storage volume
Change over period 0.0 0.0 0.0 0.0 0.0
GL/y percent change from Scenario A
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
Unsupplemented 2.2 3% 3% 0% -5%
Town Water Supply
High Security 3.3 -1% 0% 0% -1%
Unsupplemented
Sub-total 5.5 1% 2% 0% -2%
Outflows
End of system flow 266.7 80% 40% 5% -27%
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%
Table 53. Flinders River water balance – gauge 915204
915204 A B Cwet Cmid Cdry
GL/y percent change from Scenario A
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
End of system flow 149.9 81% 40% 6% -26%
Sub-total 149.9 81% 40% 6% -26%
Net evaporation
Storages
Sub-total
Unattributed fluxes
5.2 16% 16% 2% -14%
© CSIRO 2009 River modelling for northern Australia ▪ 53
Table 54. Flinders River water balance – gauge 915014
915014 A B Cwet Cmid Cdry
GL/y percent change from Scenario A
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
End of system flow 88.0 -39% 35% 6% -32%
Sub-total 88.0 -39% 35% 6% -32%
Net evaporation
Storages
Sub-total
Unattributed fluxes
15.8 -14% 10% 1% -11%
Table 55. Flinders River water balance – gauge 915012
915012 A B Cwet Cmid Cdry
GL/y
Storage volume
Change over period 0.0 0.0 0.0 0.0 0.0
GL/y percent change from Scenario A
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
General Security 12.3 0% 3% -4% -6%
Unsupplemented 44.1 -5% 4% -1% -7%
Other Uses
High Security
Unsupplemented 0.5 3% 4% -4% -7%
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%
54 ▪ River modelling for northern Australia © CSIRO 2009
Table 56. Flinders River water balance – gauge 915008
915008 A B Cwet Cmid Cdry
GL/y percent change from Scenario A
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
General Security 0.6 6% 5% 0% -11%
Unsupplemented 10.2 1% 5% -6% -11%
Other Uses
High Security
Unsupplemented 0.6 0% 2% -2% -3%
Sub-total 11.4 1% 5% -5% -11%
Outflows
End of system flow 347.7 -30% 37% -21% -31%
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%
Table 57. Flinders River water balance – gauge 915004
915004 A B Cwet Cmid Cdry
GL/y percent change from Scenario A
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
Unsupplemented 8.2 0% 4% -7% -11%
Town Water Supply
High Security
Unsupplemented 0.0 0% 5% -5% -5%
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%
© CSIRO 2009 River modelling for northern Australia ▪ 55
Scaling results
The river basin boundaries and the subdivision of the river basin into subcatchments for modelling purposes are shown
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.
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
56 ▪ River modelling for northern Australia © CSIRO 2009
Table 58. Flinders River – Streamflow scaling factors for Scenario B
Catchment J F M A M J J A S O N D Annual Monthly annual
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
© CSIRO 2009 River modelling for northern Australia ▪ 57
Table 59. Flinders River – Rainfall scaling factors for Scenario B
Catchment J F M A M J J A S O N D Annual Monthly annual
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
Catchment J F M A M J J A S O N D Annual Monthly annual
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
58 ▪ River modelling for northern Australia © CSIRO 2009
Table 61. Flinders River – Streamflow scaling factors for Scenario Cwet
Catchment J F M A M J J A S O N D Annual Monthly annual
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
© CSIRO 2009 River modelling for northern Australia ▪ 59
Table 62. Flinders River – Streamflow scaling factors for Scenario Cmid
Catchment J F M A M J J A S O N D Annual Monthly annual
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
60 ▪ River modelling for northern Australia © CSIRO 2009
Table 63. Flinders River – Streamflow scaling factors for Scenario Cdry
Catchment J F M A M J J A S O N D Annual Monthly annual
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
© CSIRO 2009 River modelling for northern Australia ▪ 61
Table 64. Flinders River – Rainfall scaling factors for Scenario Cwet
Catchment J F M A M J J A S O N D Annual Monthly annual
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
Catchment J F M A M J J A S O N D Annual Monthly annual
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
62 ▪ River modelling for northern Australia © CSIRO 2009
Table 66. Flinders River – Rainfall scaling factors for Scenario Cdry
Catchment J F M A M J J A S O N D Annual Monthly annual
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
Catchment J F M A M J J A S O N D Annual Monthly annual
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
© CSIRO 2009 River modelling for northern Australia ▪ 63
Table 68. Flinders River – Evaporation scaling factors for Scenario Cmid
Catchment J F M A M J J A S O N D Annual Monthly annual
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
Catchment J F M A M J J A S O N D Annual Monthly annual
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
64 ▪ River modelling for northern Australia © CSIRO 2009
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.
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 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
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 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
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.
• Scenario BN – recent climate and without-development
Current levels of development such as 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 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 CN – future climate and without-development
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. 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 assumes the full use of existing entitlements 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.
© CSIRO 2009 River modelling for northern Australia ▪ 65
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
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.
River model description
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).
66 ▪ River modelling for northern Australia © CSIRO 2009
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
Degree of regulation
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.
© CSIRO 2009 River modelling for northern Australia ▪ 67
Table 71. Modelled water use configuration in the Gilbert system river model
Water users Number of nodes
Volumetric limit Model notes
GL/y
Town water supply
Unsupplemented 1 0.1 Fixed demand
Agriculture
General Security 13 4.0 No On Farm Storage
Unsupplemented 19 29.9
Mining
High Security 2 7.3 Fixed demand
Unsupplemented 1 0.4 Fixed demand
Other demands
Unsupplemented 17 0.3 Fixed demand
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.
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 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
Model setup information Version Start date End date
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
Inflows No adjustment
Initial storage volumes set to level at 01/08/2007
Copperfield Dam 19GL
Other storages set to level at 01/08/2007
River system water balance – whole of system
The mass balance table (Table 73) 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.
68 ▪ River modelling for northern Australia © CSIRO 2009
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. 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
Change over period 0.0 0.0 0.0 0.0 0.0
Inflows
GL/y percent change from Scenario A
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
Unsupplemented 0.0 0% 0% 0% 0%
Agriculture
General Security 3.0 0% 0% 0% -2%
Unsupplemented 18.7 -2% 0% 1% -4%
Mining
High Security 6.6 0% 1% 0% -2%
Unsupplemented 0.4 -5% 3% -1% -13%
Other Uses
General Security 0.2 -1% 1% 0% -1%
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%
© CSIRO 2009 River modelling for northern Australia ▪ 69
River system reach water balance
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)
GL/y percent change from Scenario A
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
End of system flow 5304.2 -21% 34% 8% -17%
Sub-total 5304.2 -21% 34% 8% -17%
Unattributed fluxes
0.0 -390% -2735% 101% -831%
Table 75. Gilbert River water balance – gauge 917009
917009 A B Cwet Cmid Cdry
GL/y percent change from Scenario A
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
End of system flow 3695.1 -16% 23% 7% -15%
Sub-total 3695.1 -16% 23% 7% -15%
Unattributed fluxes
0.0 -156223% 0% 100% -67%
70 ▪ River modelling for northern Australia © CSIRO 2009
Table 76. Gilbert River water balance – gauge 917111
917111 A B Cwet Cmid Cdry
GL/y percent change from Scenario A
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
General Security 0.0 -1% 2% 0% -5%
Sub-total 0.0 -1% 2% 0% -5%
Outflows
End of system flow 2492.5 -20% 35% 9% -18%
Sub-total 2492.5 -20% 35% 9% -18%
Unattributed fluxes
288.3 -10% 14% 3% -10%
Table 77. Gilbert River water balance – gauge 917113
917113 A B Cwet Cmid Cdry
GL/y percent change from Scenario A
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
General Security 0.2 -1% 1% 0% -1%
Sub-total 0.2 -1% 1% 0% -1%
Outflows
End of system flow 382.8 -34% 45% 9% -23%
Sub-total 382.8 -34% 45% 9% -23%
Unattributed fluxes
11.6 -15% 16% 3% -11%
© CSIRO 2009 River modelling for northern Australia ▪ 71
Table 78. Gilbert River water balance – gauge 917112
917112 A B Cwet Cmid Cdry
GL/y percent change from Scenario A
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%
Unsupplemented 0.3 -1% 0% 0% -2%
Mining
High Security 2.0 0% 2% -1% -7%
Unsupplemented 0.4 -5% 3% -1% -13%
Sub-total 2.8 -1% 2% -1% -7%
Outflows
End of system flow 108.3 -18% 37% 8% -19%
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%
Table 79. Gilbert River water balance – gauge 917109
917109 A B Cwet Cmid Cdry
GL/y percent change from Scenario A
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
General Security 1.0 0% 0% -1% -1%
Unsupplemented
Sub-total 1.0 0% 0% -1% -1%
Outflows
End of system flow 1133.7 -13% 14% 5% -10%
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%
72 ▪ River modelling for northern Australia © CSIRO 2009
Table 80. Gilbert River water balance – gauge 917106
917106 A B Cwet Cmid Cdry
GL/y
Storage volume
Change over period 0.0 0.0 0.0 0.0 0.0
GL/y percent change from Scenario A
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
High Security 4.6 0% 0% 0% 0%
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%
Table 81. Gilbert River water balance – gauge 917102
917102 A B Cwet Cmid Cdry
GL/y percent change from Scenario A
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
Unsupplemented 4.3 -1% 0% 0% -2%
Sub-total 4.3 -1% 0% 0% -2%
Outflows
End of system flow 491.8 -14% -2% 4% -9%
Sub-total 491.8 -14% -2% 4% -9%
Unattributed fluxes
0.0 -9710% -4193% -10130% -5196%
© CSIRO 2009 River modelling for northern Australia ▪ 73
Table 82. Gilbert River water balance – gauge 917108
917108 A B Cwet Cmid Cdry
GL/y percent change from Scenario A
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%
Table 83. Gilbert River water balance – gauge 917001
917001 A B Cwet Cmid Cdry
GL/y percent change from Scenario A
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
General Security 1.9 0% 0% 0% -1%
Unsupplemented 12.4 -2% 0% 1% -4%
Sub-total 14.3 -2% 0% 1% -4%
Outflows
End of system flow 1114.5 -8% -2% 5% -8%
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%
74 ▪ River modelling for northern Australia © CSIRO 2009
Table 84. Gilbert River water balance – gauge 917013
917013 A B Cwet Cmid Cdry
GL/y percent change from Scenario A
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
End of system flow 213.1 -24% -7% 13% -24%
Sub-total 213.1 -24% -7% 13% -24%
Unattributed fluxes
20.3 -10% -3% 4% -15%
Table 85. Gilbert River water balance – gauge 917013
917006 A B Cwet Cmid Cdry
GL/y percent change from Scenario A
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
Unsupplemented 1.8 -1% 0% 1% -3%
Sub-total 1.8 -1% 0% 1% -3%
Outflows
End of system flow 310.7 -7% -2% 6% -10%
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%
© CSIRO 2009 River modelling for northern Australia ▪ 75
Scaling results
The river basin boundaries and the subdivision of the river basin into subcatchments for modelling purposes are shown
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.
Figure 18. 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
76 ▪ River modelling for northern Australia © CSIRO 2009
Table 86. Gilbert River – Streamflow scaling factors for Scenario B
Catchment J F M A M J J A S O N D Annual Monthly annual
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
Catchment J F M A M J J A S O N D Annual Monthly annual
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
Catchment J F M A M J J A S O N D Annual Monthly annual
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
© CSIRO 2009 River modelling for northern Australia ▪ 77
Table 89. Gilbert River – Streamflow scaling factors for Scenario Cwet
Catchment J F M A M J J A S O N D Annual Monthly annual
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
78 ▪ River modelling for northern Australia © CSIRO 2009
Table 90. Gilbert River – Streamflow scaling factors for Scenario Cmid
Catchment J F M A M J J A S O N D Annual Monthly annual
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
© CSIRO 2009 River modelling for northern Australia ▪ 79
Table 91. Gilbert River – Streamflow scaling factors for Scenario Cdry
Catchment J F M A M J J A S O N D Annual Monthly annual
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
Catchment J F M A M J J A S O N D Annual Monthly annual
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
80 ▪ River modelling for northern Australia © CSIRO 2009
Table 93. Gilbert River – Rainfall scaling factors for Scenario Cmid
Catchment J F M A M J J A S O N D Annual Monthly annual
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
Catchment J F M A M J J A S O N D Annual Monthly annual
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
Catchment J F M A M J J A S O N D Annual Monthly annual
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
Catchment J F M A M J J A S O N D Annual Monthly annual
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
Catchment J F M A M J J A S O N D Annual Monthly annual
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
© CSIRO 2009 River modelling for northern Australia ▪ 81
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.
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. 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
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 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
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.
• Scenario BN – recent climate and without-development
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 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 CN – future climate and without-development
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. 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 developments
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
82 ▪ River modelling for northern Australia © CSIRO 2009
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 was available for the Leichhardt River catchment. Hence Scenario D was not
analysed.
River model description
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
Average annual release
Average annual net evaporation
Degree of regulation
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).
© CSIRO 2009 River modelling for northern Australia ▪ 83
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
Water users Number of nodes
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
84 ▪ River modelling for northern Australia © CSIRO 2009
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.
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
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
Model setup information Version Start date End date
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
Inflows No adjustment
Initial storage volume Southedge 109.3GL
Initial storage volume for other storages set to level at 01/08/2007
River system water balance – whole of system
The mass balance table (Table 101) 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.
The directly gauged inflows represent the inflows into the model that are based on data from a river gauge. The indirectly
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
© CSIRO 2009 River modelling for northern Australia ▪ 85
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
Change over period 0.0 0.0 0.0 0.0 0.0
GL/y percent change from Scenario A
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
Unsupplemented 29.8 0% 1% -3% -1%
Mining
Unsupplemented 10.1 0% 1% -2% 0%
Town Water Supply
Unsupplemented 0.2 0% 0% 0% -1%
Other Uses
High Security 20.0 0% 0% 0% 0%
Unsupplemented 14.9 0% 2% 0% -2%
Sub-total 75.0 0% 1% -1% -1%
Outflows
End of system flow 12023.2 16% 51% -6% -26%
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%
86 ▪ River modelling for northern Australia © CSIRO 2009
River system reach water balance
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
919005 A B Cwet Cmid Cdry
GL/y
Storage volume
Change over period 0.0 0.0 0.0 0.0 0.0
GL/y percent change from Scenario A
Inflows
Subcatchments
Gauged
Ungauged 391.4 4% 19% -3% -28%
Sub-total 391.4 4% 19% -3% -28%
Diversions
Agriculture
Unsupplemented 1.9 1% 0% 0% -3%
Other Uses
High Security 20.0 0% 0% 0% 0%
Unsupplemented 0.3 0% 0% 0% 0%
Sub-total 22.2 0% 0% 0% 0%
Outflows
End of system flow 340.9 5% 23% -4% -32%
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%
© CSIRO 2009 River modelling for northern Australia ▪ 87
Table 103. Mitchell River water balance – gauge 919014
919014 A B Cwet Cmid Cdry
GL/y
Storage volume
Change over period
GL/y percent change from Scenario A
Inflows
Subcatchments
Gauged
Ungauged 742.7 3% 22% -6% -30%
Sub-total 742.7 3% 22% -6% -30%
Diversions
Agriculture
Unsupplemented 0.6 2% 1% -1% -11%
Sub-total 0.6 2% 1% -1% -11%
Outflows
End of system flow 742.0 3% 22% -6% -30%
Sub-total 742.0 3% 22% -6% -30%
Unattributed fluxes
0.0 158% -79% 30% 25%
Table 104. Mitchell River water balance – gauge 919001
919001 A B Cwet Cmid Cdry
GL/y
Storage volume
Change over period
GL/y percent change from Scenario A
Inflows
Subcatchments
Gauged 84.4 -1% 21% -8% -27%
Ungauged
Sub-total 84.4 -1% 21% -8% -27%
Diversions
Agriculture
Unsupplemented 1.8 0% 0% 0% -1%
Other Uses
High Security
Unsupplemented 0.0 0% 0% 0% 0%
Sub-total 1.9 0% 0% 0% -1%
Outflows
End of system flow 82.5 -1% 21% -8% -28%
Sub-total 82.5 -1% 21% -8% -28%
Unattributed fluxes
0.0 -108% -40% -46% -58%
88 ▪ River modelling for northern Australia © CSIRO 2009
Table 105. Mitchell River water balance – gauge 919013
919013 A B Cwet Cmid Cdry
GL/y percent change from Scenario A
Inflows
Subcatchments
Gauged 205.3 -2% 20% -8% -30%
Ungauged
Sub-total 205.3 -2% 20% -8% -30%
Diversions
Agriculture
Unsupplemented 0.1 0% 0% 0% 0%
Sub-total 0.1 0% 0% 0% 0%
Outflows
End of system flow 205.2 -2% 20% -8% -30%
Sub-total 205.2 -2% 20% -8% -30%
Unattributed fluxes
0.0 -463% -151% -151% 463%
Table 106. Mitchell River water balance – gauge 919007
919007 A B Cwet Cmid Cdry
GL/y percent change from Scenario A
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
End of system flow 340.7 6% 26% -5% -33%
Sub-total 340.7 6% 26% -5% -33%
Unattributed fluxes
0.0 -185% -231% -194% -199%
© CSIRO 2009 River modelling for northern Australia ▪ 89
Table 107. Mitchell River water balance – gauge 919003
919003 A B Cwet Cmid Cdry
GL/y percent change from Scenario A
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
Unsupplemented 4.7 1% 3% -1% -6%
Mining
Unsupplemented 0.1 0% 0% 0% 0%
Sub-total 4.8 1% 3% -1% -6%
Outflows
End of system flow 1745.5 4% 37% -6% -29%
Sub-total 1745.5 4% 37% -6% -29%
Unattributed fluxes
31.6 2% 3% -1% -8%
Table 108. Mitchell River water balance – gauge 919312
919312 A B Cwet Cmid Cdry
GL/y percent change from Scenario A
Inflows
Subcatchments
Gauged 199.3 1% 50% -3% -22%
Ungauged
Sub-total 199.3 1% 50% -3% -22%
Diversions
Sub-total
Outflows
End of system flow 199.3 1% 50% -3% -22%
Sub-total 199.3 1% 50% -3% -22%
Unattributed fluxes
90 ▪ River modelling for northern Australia © CSIRO 2009
Table 109. Mitchell River water balance – gauge 919311
919311 A B Cwet Cmid Cdry
GL/y percent change from Scenario A
Inflows
Subcatchments
Gauged
Ungauged 644.4 -6% 22% -1% -34%
Sub-total 644.4 -6% 22% -1% -34%
Diversions
Sub-total
Outflows
End of system flow 644.4 -6% 22% -1% -34%
Sub-total 644.4 -6% 22% -1% -34%
Unattributed fluxes
Table 110. Mitchell River water balance – gauge 919310
919310 A B Cwet Cmid Cdry
GL/y percent change from Scenario A
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
Unsupplemented 4.9 0% 2% 0% -3%
Sub-total 4.9 0% 2% 0% -3%
Outflows
End of system flow 909.5 -4% 30% -1% -30%
Sub-total 909.5 -4% 30% -1% -30%
Unattributed fluxes
49.8 -1% 15% 0% -20%
Table 111. Mitchell River water balance – gauge 919309
919309 A B Cwet Cmid Cdry
GL/y percent change from Scenario A
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
End of system flow 1277.1 -2% 35% -1% -26%
Sub-total 1277.1 -2% 35% -1% -26%
Unattributed fluxes
167.3 -4% 53% -3% -34%
© CSIRO 2009 River modelling for northern Australia ▪ 91
Table 112. Mitchell River water balance – gauge 919011
919011 A B Cwet Cmid Cdry
GL/y percent change from Scenario A
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
Unsupplemented 19.8 0% 1% 0% -2%
Sub-total 19.8 0% 1% 0% -2%
Outflows
End of system flow 3404.3 3% 40% -4% -28%
Sub-total 3404.3 3% 40% -4% -28%
Unattributed fluxes
194.0 3% 22% -2% -20%
Table 113. Mitchell River water balance – 919002
919002 A B Cwet Cmid Cdry
GL/y percent change from Scenario A
Inflows
Subcatchments
Gauged 134.3 -21% 40% 1% -24%
Ungauged
Sub-total 134.3 -21% 40% 1% -24%
Diversions
Sub-total
Outflows
End of system flow 134.3 -21% 40% 1% -24%
Sub-total 134.3 -21% 40% 1% -24%
Unattributed fluxes
Table 114. Mitchell River water balance – 919006
919006 A B Cwet Cmid Cdry
GL/y percent change from Scenario A
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
Unsupplemented 0.2 -4% 4% 2% -9%
Mining
Unsupplemented 4.9 0% 1% 0% -1%
Town Water Supply
Unsupplemented 0.0 0% 0% 0% 0%
Other Uses
High Security 0.0 0% 0% 0% 0%
Unsupplemented 0.0 -2% 3% 2% -5%
92 ▪ River modelling for northern Australia © CSIRO 2009
919006 A B Cwet Cmid Cdry
Sub-total 5.1 -1% 1% 0% -1%
Outflows
End of system flow 768.9 -19% 43% 0% -23%
Sub-total 768.9 -19% 43% 0% -23%
Unattributed fluxes
5.2 -10% 20% 1% -15%
Table 115. Mitchell River water balance – 919008
919008 A B Cwet Cmid Cdry
GL/y
Storage volume
Change over period 0.0 0.0 0.0 0.0 0.0
GL/y percent change from Scenario A
Inflows
Subcatchments
Gauged 485.6 -13% 40% 1% -23%
Ungauged
Sub-total 485.6 -13% 40% 1% -23%
Diversions
Sub-total
Outflows
End of system flow 485.3 -13% 40% 1% -23%
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%
© CSIRO 2009 River modelling for northern Australia ▪ 93
Table 116. Mitchell River water balance – 919004
919204 A B Cwet Cmid Cdry
GL/y
Storage volume
Change over period 0.0 0.0 0.0 0.0 0.0
GL/y percent change from Scenario A
Inflows
Subcatchments
Gauged 1429.1 12% 54% -7% -26%
Ungauged
Sub-total 1429.1 12% 54% -7% -26%
Diversions
Agriculture
Unsupplemented 0.5 0% 0% 0% -1%
Mining
Unsupplemented 0.3 0% 0% 0% -1%
Town Water Supply
Unsupplemented 0.0 0% 0% 0% 0%
Other Uses
High Security 0.0 0% 0% 0% 0%
Unsupplemented 14.6 0% 2% 0% -2%
Sub-total 15.4 0% 1% 0% -2%
Outflows
End of system flow 1413.4 12% 55% -7% -26%
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%
Table 117. Mitchell River water balance – 919009
919009 A B Cwet Cmid Cdry
GL/y percent change from Scenario A
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
End of system flow 6696.8 4% 41% -4% -25%
Sub-total 6894.2 4% 47% -5% -27%
Unattributed fluxes
349.8 3% 16% 0% -15%
94 ▪ River modelling for northern Australia © CSIRO 2009
Table 118. Mitchell River water balance – 913999
913999 A B Cwet Cmid Cdry
GL/y percent change from Scenario A
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
End of system flow 12023.2 16% 51% -6% -26%
Sub-total 12023.2 16% 51% -6% -26%
Unattributed fluxes
620.0 15% 44% -5% -25%
© CSIRO 2009 River modelling for northern Australia ▪ 95
Scaling results
The river basin boundaries and the subdivision of the river basin into subcatchments for modelling purposes are shown
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.
Figure 20. 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
96 ▪ River modelling for northern Australia © CSIRO 2009
Table 119. Mitchell River – Streamflow scaling factors for Scenario B
Catchment J F M A M J J A S O N D Annual Monthly annual
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
Catchment J F M A M J J A S O N D Annual Monthly annual
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
Catchment J F M A M J J A S O N D Annual Monthly annual
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
© CSIRO 2009 River modelling for northern Australia ▪ 97
Table 122. Mitchell River – Streamflow scaling factors for Scenario Cwet
Catchment J F M A M J J A S O N D Annual Monthly annual
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
Catchment J F M A M J J A S O N D Annual Monthly annual
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
98 ▪ River modelling for northern Australia © CSIRO 2009
Table 124. Mitchell River – Streamflow scaling factors Scenario Cdry
Catchment J F M A M J J A S O N D Annual Monthly annual
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
Catchment J F M A M J J A S O N D Annual Monthly annual
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
© CSIRO 2009 River modelling for northern Australia ▪ 99
Table 126. Mitchell River – Rainfall scaling factors for Scenario Cmid
Catchment J F M A M J J A S O N D Annual Monthly annual
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
Catchment J F M A M J J A S O N D Annual Monthly annual
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
Catchment J F M A M J J A S O N D Annual Monthly annual
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
Catchment J F M A M J J A S O N D Annual Monthly annual
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
Catchment J F M A M J J A S O N D Annual Monthly annual
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
100 ▪ River modelling for northern Australia © CSIRO 2009
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
© CSIRO 2009 River modelling for northern Australia ▪ 101
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
Change over period 5.8 0.0 0.0 0.0 0.0
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
Unsupplemented 0.0 0.0 0.0 0.0 0.2
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
Unsupplemented 0.0 0.0 1.4 0.0 14.9
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
102 ▪ River modelling for northern Australia © CSIRO 2009
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
© CSIRO 2009 River modelling for northern Australia ▪ 103
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
104 ▪ River modelling for northern Australia © CSIRO 2009
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.
© CSIRO 2009 River modelling for northern Australia ▪ 105
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.
106 ▪ River modelling for northern Australia © CSIRO 2009
5 References
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108 ▪ River modelling for northern Australia © CSIRO 2009
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.
© CSIRO 2009 River modelling for northern Australia ▪ 109
110 ▪ River modelling for northern Australia © CSIRO 2009
© CSIRO 2009 River modelling for northern Australia ▪ 111
112 ▪ River modelling for northern Australia © CSIRO 2009