River Modelling for Tasmania Volume 1: the Arthur-Inglis-Cam Region

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River modelling for Tasmania Volume 1: the Arthur-Inglis-Cam region

Ling FLN, Gupta V, Willis M, Bennett JC, Robinson KA, Paudel K, Post DA and Marvanek S

A report to the Australian Government from the CSIRO Tasmania Sustainable Yields Project

December 2009

Contributors

Project Management: David Post, Tom Hatton, Mac Kirby, Therese McGillion and Linda Merrin Report Production: Frances Marston, Susan Cuddy, Maryam Ahmad, William Francis, Becky Schmidt, Siobhan Duffy, Heinz Buettikofer, Alex Dyce, Simon Gallant, Chris Maguire and Ben Wurcker

Project Team: CSIRO: Francis Chiew, Neil Viney, Glenn Harrington, Jin Teng, Ang Yang, Glen Walker, Jack Katzfey, John McGregor, Kim Nguyen, Russell Crosbie, Steve Marvanek, Dewi Kirono, Ian Smith, James McCallum, Mick Hartcher, Freddie Mpelasoka, Jai Vaze, Andrew Freebairn, Janice Bathols, Randal Donohue, Li Lingtao, Tim McVicar and David Kent

Tasmanian Department of Bryce Graham, Ludovic Schmidt, John Gooderham, Shivaraj Gurung, Primary Industries, Parks, Miladin Latinovic, Chris Bobbi, Scott Hardie, Tom Krasnicki, Danielle Hardie and Water and Environment: Don Rockliff

Hydro Tasmania Consulting: Fiona Ling, Mark Willis, James Bennett, Vila Gupta, Kim Robinson, Kiran Paudel and Keiran Jacka

Sinclair Knight Merz: Stuart Richardson, Dougal Currie, Louise Anders and Vic Waclavik

Aquaterra Consulting: Hugh Middlemis, Joel Georgiou and Katharine Bond

Tasmania Sustainable Yields Project acknowledgments Prepared by CSIRO for the Australian Government under the Water for the Future Plan of the Australian Government Department of the Environment, Water, Heritage and the Arts. Important aspects of the work were undertaken by the Tasmanian Department of Primary Industries, Parks, Water and Environment; Hydro Tasmania Consulting; Sinclair Knight Merz; and Aquaterra Consulting. Project guidance was provided by the Steering Committee: Australian Government Department of the Environment, Water, Heritage and the Arts; Tasmanian Department of Primary Industries, Parks, Water and Environment; CSIRO Water for a Healthy Country Flagship; and the Bureau of Meteorology. Scientific rigour for this report was ensured by external reviewers, Tony Jakeman, Murray Peel and Peter Davies. Valuable input was provided by the Sustainable Yields Technical Reference Panel: CSIRO Land and Water; Australian Government Department of the Environment, Water, Heritage and the Arts; Tasmanian Department of Primary Industries, Parks, Water, and Environment; Western Australian Department of Water; and the National Water Commission. We acknowledge the Tasmanian Department of Primary Industries, Parks, Water, and Environment for providing the original TasCatch models for use in the current project, and for assistance in providing cease-to-take rules, operating rules for storages, and environmental flows. We acknowledge input from the following individuals: Richard McLoughlin, Alan Harradine, Louise Minty, Ian Prosser, Patricia Please, Martin Read, Rod Oliver, Dugald Black, Ian Loh, Albert Van Dijk, Geoff Podger, Scott Keyworth, Helen Beringen, Mary Mulcahy, Paul Jupp, Amanda Sutton, Josie Grayson, Melanie Jose, Ali Wood, Peter Fitch, Wenju Cai, Ken Currie, Eric Lam, Imogen Fullagar, Nathan Bindoff, Stuart Corney, Mike Pook and Richard Davis.

Tasmania 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 Tasmanian Department of Primary Industries, Parks, Water, and Environment; Hydro Tasmania Consulting; Sinclair Knight Merz; Aquaterra Consulting; Antarctic Climate and Ecosystems CRC; Tasmanian Irrigation Development Board; Private Forests Tasmania; and the Queensland Department of Environment and Resource Management.

Data on proposed irrigation developments were supplied by the Tasmanian Irrigation Development Board in June 2009. Data on projected increases in commercial forest plantations were provided by Private Forests Tasmania in February 2009.

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 Ling FLN, Gupta V, Willis M, Bennett JC, Robinson KA, Paudel K, Post DA and Marvanek S (2009) River modelling for Tasmania. Volume 1: the Arthur-Inglis-Cam region. A report to the Australian Government from the CSIRO Tasmania 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 Photo on cover: Inglis River near Wynyard (CSIRO) Director’s foreword

Following the November 2006 Summit on the southern Murray-Darling Basin (MDB), the then Prime Minister and MDB state Premiers commissioned CSIRO to undertake an assessment of sustainable yields of surface and groundwater systems within the MDB. The project set an international benchmark for rigorous and detailed basin-scale assessment of the anticipated impacts of climate change, catchment development and increasing groundwater extraction on the availability and use of water resources.

On 26 March 2008, the Council of Australian Governments (COAG) agreed to expand the CSIRO assessments of sustainable yield so that, for the first time, Australia would have a comprehensive scientific assessment of water yield in all major water systems across the country. This would allow a consistent analytical framework for water policy decisions across the nation. The Tasmania Sustainable Yields Project, together with allied projects for northern Australia and south-west Western Australia, will provide a nation-wide expansion of the assessments.

The CSIRO Tasmania Sustainable Yields Project is providing critical information on current and likely future water availability. This information will help governments, industry and communities consider the environmental, social and economic aspects of the sustainable use and management of the precious water assets of Tasmania.

The projects are the first rigorous attempt for the regions 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. To do this, we are undertaking 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.

To deliver on the projects CSIRO is drawing on the scientific leadership and technical expertise of national and state government agencies in Queensland, Tasmania, the Northern Territory and Western Australia, as well as Australia’s leading industry consultants. The projects are dependent on the cooperative participation of over 50 government and private sector organisations. The projects have established a comprehensive but efficient process of internal and external quality assurance on all the work performed and all the results delivered, including advice from senior academic, industry and government experts.

The projects are led by the Water for a Healthy Country Flagship, a CSIRO-led research initiative established to deliver the science required for sustainable management of water resources in Australia. By building the capacity and capability required to deliver on this ambitious goal, the Flagship is ideally positioned to accept the challenge presented by this complex integrative project.

CSIRO has given the Sustainable Yields Projects its highest priority. It is in that context that I am very pleased and proud to commend this report to the Australian Government.

Dr Tom Hatton

Director, Water for a Healthy Country

National Research Flagships

CSIRO

Executive summary

This report describes the river system modelling undertaken for the Arthur-Inglis-Cam region as part of the CSIRO Tasmania Sustainable Yields Project. The objective of the river system modelling is to estimate flows in river systems across Tasmania using a consistent Tasmania-wide modelling approach for four scenarios involving a range of climate conditions and catchment development levels. The four scenarios are:

 Scenario A – historical climate (1 January 1924 to 31 December 2007) and current development  Scenario B – recent climate (data from 1 January 1997 to 31 December 2007 were concatenated to make an 84-year sequence) and current development  Scenario C – future climate (84-year sequence scaled for ~2030 conditions) and current development  Scenario D – future climate (84-year sequence scaled for ~2030 conditions) and future development.

In this project, current development is defined as the development at the end of 2007. Future development is defined to include projected future levels of commercial forestry plantations, irrigation development and groundwater extraction. This report only considers changes in future development associated with commercial forestry plantations as this is the only factor which is likely to affect surface water availability in this region.

River system models were developed for each catchment to describe current infrastructure, water demands and water management rules. These models were used to assess the implications of changed inflows for water availability and the reliability of water supply to users. The models are node-link network models developed in Hydstra and they include water allocations and extractions, streamflow routing and environmental flows. Gridded runoff, rainfall and areal potential evapotranspiration were inputs to the models. The models were run on a daily time step and the runoff from each subcatchment was routed through the river network to the next subcatchment downstream.

Over the historical period (1924 to 2007), the Arthur-Inglis-Cam region had a total mean annual flow of 4789 GL/year, and a low level of extraction with a mean annual extraction of 92.6 GL/year (1.9 percent of total water in the region). The Emu catchment has the greatest level of extraction (31.5 GL/year or 15 percent of total water in the Emu catchment) due to requirements for water from industry and town water supplies.

The volume of water extracted in the region is not expected to reduce significantly under the future climate (Scenario C) relative to the historical climate (Scenario A). Extractions reduce from 92.6 GL/year under the historical climate to 91.4 GL/year under the dry extreme future climate (Scenario Cdry), a reduction of 1.2 GL/year (1 percent). The largest impact is in the driest years, with a projected decrease of up to 7 percent in extracted water in the Emu catchment for the driest one-year period under the dry extreme future climate relative to the historical climate. This reflects the low level of water use in the region. By comparison, future climate has a greater impact on total end-of-system flows for the region, ranging from a decrease of 2 percent (under the wet extreme future climate (Scenario Cwet)) to a decrease of 11 percent (under the dry extreme future climate) with a median reduction of 5 percent (under the median future climate (Scenario Cmid)).

Under the recent climate (Scenario B), the monthly mean discharge is lower than the long-term mean in all catchments in all months with the exception of September and October. The flow duration curves show that flows under the recent climate are generally lower than the long-term mean over the full range of flows. The volume of extracted water decreases by a mean of 2 GL/year (2 percent) under the recent climate relative to the historical climate. The non-extracted water decreases by a mean of 656 GL/year (14 percent).

Future development in the Arthur-Inglis-Cam region includes a projected increase of 75 km2 in commercial forestry plantations, which will increase total forest cover from 6 percent of the region to 7 percent of the region by 2030. The majority of this projected increase is in the north-east of the region. Catchment runoff is projected to decrease by a maximum of 3.7 percent in the Blythe catchment due to the expansion of forestry plantations under future development (Scenario D). Reductions in inflows for the region as a whole are minimal, as are impacts on end-of-system flows.

ii ▪ River modelling for Tasmania. Volume 1: the Arthur-Inglis-Cam region © CSIRO 2009 Table of contents

1 Introduction ...... 1 2 Methods...... 5 2.1 Allocations and extractions ...... 5 2.1.1 Water entitlements...... 5 2.1.2 Unlicensed storages ...... 6 2.1.3 Unlicensed extractions ...... 7 2.1.4 Environmental flows and releases...... 7 2.1.5 Diversions, storages, and model customisation ...... 8 2.2 Future development ...... 10 3 Under historical climate (Scenario A) and future climate (Scenario C)...... 12 3.1 Water balance and water availability...... 12 3.2 Storage behaviour...... 22 3.3 Consumptive water use...... 24 3.4 End-of-system river flow...... 37 3.5 Share of available resource ...... 44 4 Under historical climate (Scenario A) and recent climate (Scenario B) ...... 51 5 Under future development (Scenario D)...... 57 5.1 Hydrological impacts of future development ...... 57 6 Conclusions ...... 64 7 References...... 65

Tables

Table 1. Catchments in the Arthur-Inglis-Cam region...... 4 Table 2. Large storages in the Arthur-Inglis-Cam region...... 4 Table 3. Department of Primary Industries, Parks, Water and Environment surety descriptions (from DPIPWE, 2009) ...... 6 Table 4. Extraction restriction rules...... 8 Table 5. Mean annual water balance for each catchment under scenarios A and C ...... 13 Table 6. Storage behaviour under scenarios A and C...... 23 Table 7. Allocated and extracted mean annual flows for catchments under scenarios A and C ...... 26 Table 8. Mean reliability of high and low priority annual allocations for catchments under scenarios A and C (annual)...... 27 Table 9. Mean reliability of high and low priority allocations under scenarios A and C (summer – October to March inclusive) ...... 28 Table 10. Mean reliability of high and low priority allocations under scenarios A and C (winter – April to September inclusive)...... 29 Table 11. Indicators of use during dry periods for catchments under Scenarios A and change under Scenario C relative to Scenario A ...... 36 Table 12. Peak flows for catchments under scenarios P and A, and under Scenario C relative to Scenario A ...... 41 Table 13. Percentage of time end-of-system flow is greater than1 ML/day under scenarios P, A and C...... 42 Table 14. End-of-system flow for catchments during dry periods under Scenario A, and under Scenario C relative to Scenario A.43 Table 15. Extracted and non-extracted shares of water for Arthur-Inglis-Cam region under scenarios A and C (annual)...... 44 Table 16. Extracted and non-extracted shares of water for catchments under scenarios A and C (annual)...... 47 Table 17. Extracted and non-extracted shares of water for Arthur-Inglis-Cam region under scenarios A and C (summer – October to March inclusive) ...... 48 Table 18. Extracted and non-extracted shares of water for catchments under scenarios A and C (summer – October to March inclusive) ...... 49 Table 19. Percentage of water extracted as a proportion of total end-of-system flow for catchments under scenarios A and C (annual)...... 50 Table 20. Percentage of water extracted as a proportion of total end-of-system flow for catchments under scenarios A and C (summer – October to March inclusive)...... 50 Table 21. Percentage of water extracted as a proportion of total end-of-system flow for catchments under scenarios A and C (winter – April to September inclusive) ...... 50 Table 22. Mean annual extracted and non-extracted shares of water for Arthur-Inglis-Cam region under scenarios A and B...... 54 Table 23. Extracted and non-extracted shares of water for Arthur-Inglis-Cam region under scenarios A and B (summer – October to March inclusive) ...... 54 Table 24. Mean annual extracted and non-extracted shares of water for catchments under scenarios A and B...... 55 Table 25. Extracted and non-extracted shares of water for catchments under scenarios A and B (summer – October to April inclusive) ...... 56

© CSIRO 2009 River modelling for Tasmania. Volume 1: the Arthur-Inglis-Cam region ▪ iii Table 26. Comparison of inflows from catchment runoff under Scenario D relative to Scenario C ...... 57 Table 27. Percent time end-of-system flow for catchments is greater than 1 ML/day under Scenario D relative to Scenario C...... 57 Table 28. Comparison of extractions for catchments under Scenario D relative to Scenario C ...... 58 Table 29. Comparison of change in peak flows for catchments under Scenario D relative to Scenario C...... 63

Figures

Figure 1. Project extent and reporting regions...... 1 Figure 2. Land cover, major rivers and towns in the Arthur-Inglis-Cam region...... 2 Figure 3. Modelled catchments, major storages and reporting locations in the Arthur-Inglis-Cam region ...... 3 Figure 4. Subcatchment delineation and WIMS licence locations ...... 7 Figure 5. Increase in forest cover due to future commercial forest plantations in the Arthur-Inglis-Cam region ...... 11 Figure 6. River transects showing streamflow under scenarios P, A and C ...... 19 Figure 7. End-of-system (EOS) streamflow in the Arthur-Inglis-Cam region under Scenario A, and difference from Scenario A under scenarios (a) Cwet, (b) Cmid and (c) Cdry ...... 22 Figure 8. Storage behaviour over representative ten-year period under scenarios A and C...... 24 Figure 9. Total annual extractions for Arthur-Inglis-Cam region under Scenario A, and difference from Scenario A under scenarios (a) Cwet, (b) Cmid and (c) Cdry...... 25 Figure 10. Allocation and extraction reliability for catchments under scenarios A and C (annual) ...... 30 Figure 11. Allocation and extraction for catchments reliability under scenarios A and C (summer – October to March inclusive) ...33 Figure 12. Mean monthly end-of-system flow under and daily flow duration curves under scenarios P, A and C ...... 37 Figure 13. Extracted and non-extracted shares of water for Arthur-Inglis-Cam region under scenarios A and C (annual)...... 44 Figure 14. Extracted and non-extracted shares of water for catchments under scenarios A and C (annual) ...... 45 Figure 15. Mean end-of-system monthly flow and daily flow duration curves for catchments under scenarios A and B ...... 51 Figure 16. Mean annual extracted and non-extracted shares of water for Arthur-Inglis-Cam region under scenarios A and B...... 54 Figure 17. Mean monthly end-of-system flow under scenarios P, A and C; and changes under Scenario D relative to Scenario C 61

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1 Introduction

This report is one in a series of technical reports from the CSIRO Tasmania Sustainable Yields Project. The terms of reference for the project require an assessment of the current and likely future extent and variability of surface and groundwater resources in Tasmania. This information will help governments, industry and communities consider the environmental, social and economic aspects of the sustainable use and management of the precious water assets of Tasmania.

The purpose of this report is to describe in detail the river system modelling undertaken for the project. The main objective of the river system modelling is to estimate flows in river systems across Tasmania for four scenarios using a consistent Tasmania-wide modelling approach, recognising that the natural and managed behaviour of rivers means that variability in runoff is not uniformly translated to variability in river flows and water uses. The four scenarios are:

 Scenario A – historical climate (1 January 1924 to 31 December 2007) and current development  Scenario B – recent climate (data from 1 January 1997 to 31 December 2007 were concatenated to make an 84-year sequence) and current development  Scenario C – future climate (~2030) and current development (84-year sequence scaled for ~2030 conditions)  Scenario D – future climate (~2030) and future development (84-year sequence scaled for ~2030 conditions).

These were compared with a fifth scenario, Scenario P, which represents water availability modelled with historical climate, current infrastructure and no extractions. This allows the impact of extractions to be explicitly considered.

The results of the climate and runoff modelling are key inputs to the river system modelling. The climate and runoff modelling are described in separate reports by Post et al. (2009) and Viney et al. (2009) respectively.

This report describes the river system modelling and results for the Arthur-Inglis-Cam region. The river system modelling method is described in Section 2. The key modelling results for each scenario are presented in sections 3 to 5. This report is part of a series of reports describing river system modelling for each of the five regions, namely the Arthur-Inglis-Cam, Mersey-Forth, Pipers-Ringarooma, South Esk and Derwent-South East regions (Ling et al., 2009a–e).

The reporting regions are shown in Figure 1. The project provides only limited reporting on sustainable yields for parts of the west coast and south-west and for the smaller offshore islands. Figure 2 illustrates the location of the major towns and main land uses in the region. A map of the reporting locations in the Pipers-Ringarooma region is shown in Figure 3.

Figure 1. Project extent and reporting regions

Figure 2. Land cover, major rivers and towns in the Arthur-Inglis-Cam region

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Figure 3. Modelled catchments, major storages and reporting locations in the Arthur-Inglis-Cam region

Table 1. Catchments in the Arthur-Inglis-Cam region

Number Catchment Area Mean Annual Mean annual Mean annual Rainfall Runoff extraction km2 mm GL GL 01 Flinders Island 1316 766 169.0 1.9 23 Arthur 2493 1757 2547.0 4.9 24 Welcome 336 1139 76.7 0.4 25 King Island 1091 968 234.8 3.8 26 Montagu 360 1245 135.5 1.9 27 Duck 509 1232 239.4 12.8 28 Black-Detention 578 1322 319.2 11.2 29 Inglis-Flowerdale 571 1384 362.6 13.1 30 Cam 286 1425 160.0 4.2 31 Emu 246 1565 252.8 31.5 32 Blythe 365 1383 261.7 6.9

For modelling purposes, the Arthur-Inglis-Cam region was divided into 11 catchments (see Table 1). A large proportion of the end-of-system (EOS) flow comes from the Arthur catchment, which is the largest catchment by area, with the highest mean annual rainfall. Rainfall varies across the region from a mean of 766 mm/year over the Flinders Island catchment to 1757 mm/year over the Arthur catchment.

The Arthur-Inglis-Cam region includes a number of large storages which were modelled as part of the river system. See Table 2 for details of these storages. The release represents controlled releases only and not spill from the storages. The degree of regulation is calculated by dividing the mean annual releases by the mean annual inflow.

Table 2. Large storages in the Arthur-Inglis-Cam region

Effective Mean Mean Degree of storage annual annual regulation inflow releases GL GL/y Major irrigation supply reservoirs Companion Reservoir 1.35 29.20 10.36 0.35 Guide Reservoir 1.60 10.28 2.48 0.24 Lake Mikany 2.77 15.16 2.22 0.15 Pet Reservoir 2.50 11.62 4.31 0.37 Talbots Lagoon 2.75 20.48 4.74 0.23 Region total 10.97 86.74 24.11 0.28

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2 Methods

This section is a summary of the generic approach used for river system modelling and a brief description of the 11 catchment models in the Arthur-Inglis-Cam region.

River system models describing current infrastructure, water demands and water management rules were used to assess the implications of changed inflows for water availability and the reliability of water supply to users. Most of the river system models are based on the TasCatch models developed for Department of Primary Industries, Parks, Water and Environment (DPIPWE) (Willis, 2008). These models were funded by the Australian Government Water Fund, for the Water Smart Australia Project, Better Information for Better Outcomes Enhancing Water Planning in Tasmania and the Tasmanian Government SMART Farming budget initiative. New models were developed for the catchments which were not covered by existing DPIPWE models.

TasCatch models are node-link network models developed in Hydstra (Kisters, 2009) which include a water balance model, streamflow routing, water allocations and extractions, and environmental flows. For the purposes of this project, the water balance and streamflow lag and attenuation were removed from the models. This is because gridded runoff, rainfall and evaporation were provided as inputs to the models (Viney et al., 2009). The lag and attenuation of streamflow was therefore removed as the calibration technique used to produce the input runoff grid implicitly included routing. The models run on a daily time step and route the runoff through the river system. The runoff in each subcatchment was calculated as the mean of the gridded runoff over the subcatchment. Runoff from each grid cell was weighted in the averaging process depending on the proportion of the grid cell that fell within a subcatchment. Subcatchment runoff was then routed through the river network to the next subcatchment downstream. In areas where a number of catchment models flow into one another in series, the models were run in logical sequence so that the outflow from the upstream model was an input to the downstream model. Running of the models was automated so that all catchment models were run in logical order for each scenario.

Rainfall and evaporation grids were used to calculate the rainfall and evaporation occurring over the surface area of storages within the models.

Model subcatchment delineation and definition of the river network was initially performed using CatchmentSIM GIS software (Catchment Simulation Solutions, 2009). Within a given catchment, subcatchments were defined to be of similar size and to ensure that the routing length between catchment centroids was representative of the river length. Subcatchments were broken upstream of river junctions. The outputs were visually checked to ensure accurate representation of the catchment, and modifications were made manually as required. The subcatchment delineation is shown in Figure 4.

2.1 Allocations and extractions

2.1.1 Water entitlements

Information on the current water entitlements as of December 2008 was obtained from DPIPWE’s Water Information Management System (WIMS) database. WIMS includes an annual allocation and period for each licence. For example a particular licence may be for 200 ML from October to February. Each licence in the catchment is of a given surety (from 1 to 8), with surety 1 to 4 representing high priority extractions for modelling purposes and surety 5 to 8 representing low priority. Details of surety levels are given in Table 3 and the location of WIMS licences are shown in Figure 4.

Table 3. Department of Primary Industries, Parks, Water and Environment surety descriptions (from DPIPWE, 2009)

Surety Description High priority 1 Rights for the taking of water for domestic purposes, consumption by livestock or firefighting under Part 5 of the Water Management Act 1999 and rights of councils to take water under Part 6 of the Act. Surety 1 water is expected to be available at about 95 percent reliability. 2 The water provision allocated to supply the needs of ecosystems dependent on the water resource. 3 Rights of licensees granted a water licence as a replacement of the ‘prescriptive rights’ (‘pre-Hydro Tasmania rights’) granted under the previous Water Act 1957. 4 Rights of special licensees such as Hydro Tasmania. Low priority 5 Rights issued for the taking of water otherwise than for the purposes described above under surety levels 1 to 4. This includes rights issued for the taking of water under Part 6 of the Act for direct extraction, and for winter storage in dams, for use for irrigation or other commercial purposes. Surety 5 water is expected to be available at about 80 percent reliability. 6 Rights at this surety level issued for the taking of water under Part 6 of the Act for direct extraction for use for irrigation and other commercial purposes and for winter storage in dams. Surety 6 water is expected to be available at less than 80 percent reliability. 7, 8 Water allocations available with a lower level of reliability than a surety 6 allocation.

There is no record of actual extraction amounts over the year because extractions are currently not metered. In the absence of any information on the monthly profile of irrigation extractions, it was assumed that the allocation was extracted evenly over the allocation period, resulting in a constant daily allocation over the allocation period. Allocations were accumulated in each subcatchment, and daily extraction of the allocated amount was attempted, based on surety priority. Where sufficient water is not available for the full allocation, the extracted amount equalled the amount available.

2.1.2 Unlicensed storages

In Tasmania, a water licence is not required for storages of less than 1 ML. Numbers of unlicensed storages were estimated by visually identifying small dams not included in the WIMS database as extractions in selected catchments. These results were then extrapolated to other similar catchments. Where unlicensed storages had been estimated for a catchment in the TasCatch modelling process, these figures were used (Willis, 2008). For the remaining areas a combination of dam counting and extrapolation of unlicensed storages in neighbouring catchments was used. Dams were manually counted in all calibration catchment areas (details of calibration catchments can be found in Viney et al. (2009)).

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Figure 4. Subcatchment delineation and WIMS licence locations

2.1.3 Unlicensed extractions

It is assumed that there will be some unlicensed extractions. The volume of unlicensed extractions for each catchment was estimated based on local advice provided by DPIPWE.

2.1.4 Environmental flows and releases

Environmental flows were included in the models where they had been set by DPIPWE and information was provided as restriction rules (shown in Table 4). In the Arthur-Inglis-Cam region environmental releases have been set for sections of the Pet River (Emu catchment), Guide River (Cam catchment) and Duck River (Duck catchment). These are detailed in Section 2.1.5.

2.1.5 Diversions, storages, and model customisation

A number of catchments include water diversion infrastructure or specific rules which control extractions. This includes rivers where a ‘cease-to-take’ flow rule is in place, meaning that extractions from the river must be ceased when flow in the river at a specified location falls below a set minimum (or threshold) for a set number of days. Flow rules are set in stages, with stage 1 as the first rule to be enforced, followed by stage 2, followed by the rules for other stages. In catchments where a flow rule is in place, the models required custom coding to account for associated operating rules, and these were treated as a reduction in allocation. Restriction rules for catchments in Arthur-Inglis-Cam region are shown in Table 4.

Table 4. Extraction restriction rules

River Location Catchment Month Threshold Number of days below Restriction rule threshold before restriction enforced ML/d Duck Trowutta Duck All year 25.0 1 All surety 6, 7 direct extractions Road are banned Duck Trowutta Duck All year 25.0 2 All surety 5, 6, 7 direct extractions Road are banned Black South Forest Black- All year 2.6 1 All direct extractions banned Road Detention Detention Newhaven Black- All year 2.0 1 All direct extractions banned Road Detention Detention Coopers Black- All year 2.0 1 All direct extractions banned Road Detention Welcome Weir Welcome All year 1.8 1 All direct extractions banned Seabrook Nunns Road Inglis- All year 2.2 1 All direct extractions banned Creek Flowerdale Blackfish Lowries Inglis- All year 1.3 1 All direct extractions banned Creek Road Flowerdale

Generic model functions representing storage and restriction rules were coded for use in the models. The values specific to the catchment conditions were passed to these functions during the running of the model. Customisations of catchment models within the Arthur-Inglis-Cam region are briefly described below. A more detailed description of the models can be found in Willis et al. (2009).

Duck River

Lake Mikany is a major storage in the Duck River catchment. Water is extracted from the pump station on Deep Creek, downstream of the lake. The extracted water is considered water lost from the system. An industrial user and the Smithton and Stanley townships are the major water users from this lake.

An environmental release of 1.7 ML/day downstream of pump station is mandated. The mean daily extraction rates from Lake Mikany for winter and summer are 3.7 ML/day and 5.0 ML/day respectively. The lake has an effective storage of 2770 ML.

Emu River Model

Burnie Mill Water Supply System

A small but significant portion of the Arthur River catchment is diverted into the upper Emu catchment as part of the Burnie Mill Water Supply System (BMWSS), which provides water for industrial users.

There are three major elements to the BMWSS:

1. Talbots Lagoon, on the upper reach of the Wey River (part of the Arthur River basin), which releases water into the Wey River as required.

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2. Wey River Weir and Diversion Canal, located downstream of Talbots Lagoon, which diverts up to 60 ML/day from Wey River to the upper Emu River. When the canal’s capacity is exceeded, the additional water spills over the Wey River Weir into the Wey River (and eventually onto the Arthur River).

3. Companion Reservoir, on the upper reaches of the Emu River downstream of the Wey River diversion canal, which releases water into the Emu River as required.

The BMWSS effectively annexes 31 km2 of the Arthur River basin to the Emu River catchment. This is treated as part of the Emu catchment in the Emu River model. To account for instances when the Wey River Diversion Canal’s capacity is exceeded, the Emu River Model produces a time series of spill over the Wey River Weir. This time series is then input into the Arthur River model.

The terms of the original agreement for operation of the BMWSS stipulated that the system will be operated to ensure that up to 65 ML/day is released from the BMWSS (Companion Dam) into the Emu River such that:

 90 ML/day could be extracted at the Emu River Weir at Fern Glade Reserve (Burnie)  6 ML/day could be extracted at Hampshire (Knoop, 2000)

In the absence of any other information, the rule coded into the Emu model assumes that the BMWSS is operated in accordance with this original agreement.

Burnie Mill Water Use

An industrial user has licences to extract approximately 30,000 ML/year, which translates to an approximate daily extraction of 81 ML/day at Emu River Weir at Fern Glade Reserve (Burnie). In the absence of more detailed information, the Emu model assumes this demand to be a constant 81 ML/day. The use of a constant rate of extraction is appropriate for such an industrial application. Unlike irrigation, industrial operation is not affected by seasonal (or other natural) influences.

Burnie Town Water Supply System

A small but significant portion of the Cam River catchment is diverted into the Pet River in the Emu catchment as part of the Burnie Town Water Supply System (BTWSS) which was designed to provide sufficient water to maintain the water supply for the regional centre of Burnie. The system is operated by Burnie City Council.

There are two major elements to the BTWSS:

1. Guide Reservoir and Canal, located in the upper reaches of the Guide River in the Cam catchment. The Guide Canal diverts water into upper Reaches of the Pet River.

2. Pet Reservoir (located below the Guide Canal outlet), and town water supply offtake pipe.

The Burnie Town Water Supply system effectively annexes 15 km2 of the Cam River catchment to the Emu River catchment. This is treated as part of the Emu catchment in the Emu River model. To account for instances when the water is released from the Guide Reservoir into the Guide River (for environmental releases or when the reservoir spills) and then into the Cam River, the Emu Model produces a time series of downstream outflows from the Guide Reservoir. This time series is then input to the Cam River model.

Burnie City Council provided detailed operating rules of the Burnie Town Water Supply system for use by this project (P Triffett (Burnie City Council), 2009, pers. comm.). The Town Water Supply System is operated as follows:

Guide Reservoir and Canal:

 5 ML/day is transferred through the Guide Canal to the Pet River from April to September (inclusive)  8 ML/day is transferred through the Guide Canal to the Pet River from October to March (inclusive)  An environmental release of 0.3 ML/day into the Guide River year-round.

Pet Reservoir:

 18 ML/day is extracted by pipe from Pet Reservoir from April to September (inclusive) to supply Burnie with town water  5 ML/day is extracted by pipe from Pet Reservoir from October to March (inclusive) to supply Burnie with town water  An environmental release of 0.3 ML/day into the Pet River year-round.

Cam River Model

The Burnie Town Water Supply System effectively annexes 15 km2 of the Cam River catchment to the Emu River catchment. This region is treated as part of the Emu River catchment, and is modelled by the Emu River model, as described above. A proportion of water falling on this 15 km2 area does flow into the Cam River catchment. The Emu Model produces a time series that accounts for this water, which is an input to the Cam River model.

Arthur River Model

The Burnie Mill Water Supply System effectively annexes 31 km2 of the Arthur River catchment to the Emu River catchment. This region is treated as part of the Emu River catchment, and is modelled by the Emu River model, as described above. A proportion of water falling on this 31 km2 area does flow into the Arthur River basin. The Emu Model produces a time series that accounts for this water, which is an input to the Arthur River model.

2.2 Future development

No future irrigation developments are proposed in the Arthur-Inglis-Cam region. Future development in the Arthur-Inglis-Cam region includes a projected increase of 75 km2 in commercial forestry plantations. This has the effect of taking total forest cover from 6 percent of the region to 7 percent of the region by 2030. The majority of this projected increase is in the north-east of the region (Viney et al, 2009). Future increases in forestry in the region are shown in Figure 5.

10 ▪ River modelling for Tasmania. Volume 1: the Arthur-Inglis-Cam region © CSIRO 2009

Figure 5. Increase in forest cover due to future commercial forest plantations in the Arthur-Inglis-Cam region

3 Under historical climate (Scenario A) and future climate (Scenario C)

This section reports on hydrology under Scenario A and on hydrology under Scenario C relative to Scenario A. Three scenarios are presented for Scenario C: wet extreme (Scenario Cwet), median (Scenario Cmid) and dry extreme (Scenario Cdry). The selection of these scenarios was based on projected changes in mean annual runoff from the 14 km resolution pattern-scaled projections of the 15 global climate models (GCMs). The selection of climate scenarios is described in detail by Viney et al. (2009). In summary, the wettest of the three global warming projections from the second wettest GCM (MIROC) was chosen as Scenario Cwet. The projection representing 1.0 degree global warming from the eighth wettest GCM (MIUB) was chosen as Scenario Cmid. The driest of the three global warming projections from the second driest GCM (NCAR-CCSM) was chosen as Scenario Cdry. This selection of scenarios Cwet, Cmid and Cdry was performed separately for each region. As the selection of these scenarios was based on mean annual runoff over the region, they can vary in order on the basis of season and catchment. In many catchments in the Arthur-Inglis-Cam region, this results in a lower flow during summer under Scenario Cmid relative to Scenario Cdry. A higher winter flow is also observed under Scenario Cmid relative to Scenario Cwet in some parts of the region.

Statistics reported for ‘summer’ or ‘winter’ refer to October to March and April to September respectively.

3.1 Water balance and water availability

The mass balance table (Table 5a–k) shows the net fluxes for each catchment in the Arthur-Inglis-Cam region. Fluxes under Scenario A are presented as GL/year, while fluxes under all other scenarios are presented as a percentage change relative to Scenario A.

The storage volumes refer to the major lakes within the region. The inflows are separated into flows from catchment runoff, and flows from hydro-electric schemes. The catchment losses include any water transfers (diversions) into or out of the catchment, and evaporation from major storages. Extractions are shown based on surety level. The catchment losses are positive for a net loss for the catchment and negative for a net gain (for example, the loss will be negative if rainfall over a storage surface exceeds evaporation, or water is transferred into a catchment).

The net catchment transfers/losses represent direct extractions from storages, and inter-catchment transfer of water. In the Arthur-Inglis-Cam region these transfers include:

 transfer of water into Arthur catchment when Wye River Weir spills in the Emu catchment,  direct extraction from Lake Mikany in the Duck catchment,  transfer of water into Cam catchment from Guide River in the Emu catchment,  transfer of water from the Emu catchment to the Cam catchment (Guide River) and Arthur catchment (Wye River Weir spill) and direct extractions from Pet Reservoir.

Table 5 shows that the mean annual catchment runoff decreases under Scenario C relative to Scenario A for all catchments in the region, other than Flinders Island where catchment runoff is higher under scenarios Cwet and Cmid, relative to Scenario A. There are larger catchment losses under Scenario C relative to Scenario A, in all catchments which include storages, reflecting an increase in evaporation under Scenario C. The extraction amounts decrease slightly or remain the same under Scenario C relative to Scenario A. In the Emu and Cam catchments, extractions are 1 percent greater under Scenario Cdry compared to Scenario Cmid. This reflects the fact that low flows under Scenario Cdry are higher than they are under Scenario Cmid in these catchments. This can occur as the selection of scenarios Cdry, Cmid and Cwet was based on annual runoff for each region. As a result, Scenario Cmid can be drier than Scenario Cdry on a seasonal and catchment basis.

12 ▪ River modelling for Tasmania. Volume 1: the Arthur-Inglis-Cam region © CSIRO 2009

Table 5. Mean annual water balance for each catchment under scenarios A and C

(a) 01_Flinders Island

A Cwet Cmid Cdry GL/y percent change relative to Scenario A Storage volume Mean annual change in volume na na na na Inflows From catchment runoff 169.0 5% 2% -8% From flows downstream of hydro schemes na na na na Total (inflows) 169.0 5% 2% -8% Outflows Net catchment transfers/losses (including storages if na na na na any) Net evaporation (evaporation – rainfall) from storages na na na na Sub-total (net transfer and net evaporation) na na na na Extractions Surety 1 0.0 1% -1% -1% Surety 2 0.0 na na na Surety 3 0.0 na na na Surety 4 0.0 na na na Surety 5 0.5 0% -1% -2% Surety 6 0.3 0% 0% -1% Surety 7 0.0 na na na Surety 8 0.0 na na na Unlicensed 1.1 0% 0% -1% Sub-total (extractions) 1.9 0% 0% -1% End-of-system (EOS) streamflow 167.0 5% 2% -8% Total (outflows) 169.0 5% 2% -8% na – not applicable (b) 23_Arthur

A Cwet Cmid Cdry GL/y percent change relative to Scenario A Storage volume Mean annual change in volume na na na na Inflows From catchment runoff 2574.0 -2% -4% -9% From flows downstream of hydro schemes na na na na Total (inflows) 2574.0 -2% -4% -9% Outflows Net catchment transfers/losses (including storages if -29.6 3% 7% 12% any) Net evaporation (evaporation – rainfall) from storages na na na na Sub-total (net transfer and net evaporation) -29.6 3% 7% 12% Extractions Surety 1 0.1 0% 0% 0% Surety 2 0.0 na na na Surety 3 0.0 na na na Surety 4 0.0 na na na Surety 5 1.3 0% 0% 0% Surety 6 0.0 na na na Surety 7 0.0 na na na Surety 8 0.0 na na na Unlicensed 3.5 0% 0% 0% Sub-total (extractions) 4.9 0% 0% 0% End-of-system (EOS) streamflow 2598.7 -2% -5% -9% Total (outflows) 2574.0 -2% -4% -9% na – not applicable

Table 5. Mean annual water balance for each catchment under scenarios A and C (continued)

(c) 24_Welcome A Cwet Cmid Cdry GL/y percent change relative to Scenario A Storage volume Mean annual change in volume na na na na Inflows From catchment runoff 76.7 -5% -12% -21% From flows downstream of hydro schemes na na na na Total (inflows) 76.7 -5% -12% -21% Outflows Net catchment transfers/losses (including storages if na na na na any) Net evaporation (evaporation – rainfall) from storages na na na na Sub-total (net transfer and net evaporation) na na na na Extractions Surety 1 0.0 na na na Surety 2 0.0 na na na Surety 3 0.0 na na na Surety 4 0.0 na na na Surety 5 0.3 0% -1% -1% Surety 6 0.0 na na na Surety 7 0.0 na na na Surety 8 0.0 na na na Unlicensed 0.0 0% 0% 0% Sub-total (extractions) 0.4 0% -1% -1% End-of-system (EOS) streamflow 76.3 -5% -12% -22% Total (outflows) 76.7 -5% -12% -21% na – not applicable (d) 25_King Island

A Cwet Cmid Cdry GL/y percent change relative to Scenario A Storage volume Mean annual change in volume na na na na Inflows From catchment runoff 234.8 -7% -11% -20% From flows downstream of hydro schemes na na na na Total (inflows) 234.8 -7% -11% -20% Outflows Net catchment transfers/losses (including storages if na na na na any) Net evaporation (evaporation – rainfall) from storages na na na na Sub-total (net transfer and net evaporation) na na na na Extractions Surety 1 0.2 0% -1% -1% Surety 2 0.0 na na na Surety 3 0.0 na na na Surety 4 0.0 na na na Surety 5 0.8 0% -1% -1% Surety 6 0.0 na na na Surety 7 0.0 na na na Surety 8 0.0 na na na Unlicensed 2.8 0% -1% -1% Sub-total (extractions) 3.8 0% -1% -1% End-of-system (EOS) streamflow 231.0 -7% -11% -21% Total (outflows) 234.8 -7% -11% -20% na – not applicable

14 ▪ River modelling for Tasmania. Volume 1: the Arthur-Inglis-Cam region © CSIRO 2009

Table 5. Mean annual water balance for each catchment under scenarios A and C (continued)

(e) 26_Montagu A Cwet Cmid Cdry GL/y percent change relative to Scenario A Storage volume Mean annual change in volume na na na na Inflows From catchment runoff 135.5 -3% -7% -16% From flows downstream of hydro schemes na na na na Total (inflows) 135.5 -3% -7% -16% Outflows Net catchment transfers/losses (including storages if na na na na any) Net evaporation (evaporation – rainfall) from storages na na na na Sub-total (net transfer and net evaporation) na na na na Extractions Surety 1 0.2 -1% -4% -3% Surety 2 0.0 na na na Surety 3 0.0 na na na Surety 4 0.0 na na na Surety 5 1.4 -1% -2% -2% Surety 6 0.0 na na na Surety 7 0.0 na na na Surety 8 0.0 na na na Unlicensed 0.3 -1% -3% -2% Sub-total (extractions) 1.9 -1% -2% -2% End-of-system (EOS) streamflow 133.7 -3% -7% -16% Total (outflows) 135.5 -3% -7% -16% na – not applicable (f) 27_Duck

A Cwet Cmid Cdry GL/y percent change relative to Scenario A Storage volume Mean annual change in volume 0.0 4% -14% -5% Inflows From catchment runoff 239.4 -2% -4% -13% From flows downstream of hydro schemes na na na na Total (inflows) 239.4 -2% -4% -13% Outflows Net catchment transfers/losses (including storages if 1.6 0% 0% 0% any) Net evaporation (evaporation – rainfall) from storages -0.1 18% 54% 79% – Lake Mikany Sub-total (net transfer and net evaporation) 1.5 1% 4% 5% Extractions Surety 1 0.8 0% 0% 0% Surety 2 0.0 na na na Surety 3 0.0 na na na Surety 4 0.0 na na na Surety 5 9.5 0% -2% -2% Surety 6 0.2 0% -1% -2% Surety 7 0.0 na na na Surety 8 0.0 na na na Unlicensed 2.3 -1% -5% -5% Sub-total (extractions) 12.8 -1% -2% -3% End-of-system (EOS) streamflow 225.1 -2% -5% -14% Total (outflows) 239.4 -2% -4% -13% na – not applicable

Table 5. Mean annual water balance for each catchment under scenarios A and C (continued)

(g) 28_Black-Detention

A Cwet Cmid Cdry GL/y percent change relative to Scenario A Storage volume Mean annual change in volume na na na na Inflows From catchment runoff 319.2 -2% -5% -13% From flows downstream of hydro schemes na na na na Total (inflows) 319.2 -2% -5% -13% Outflows Net catchment transfers/losses (including storages if na na na na any) Net evaporation (evaporation – rainfall) from storages na na na na Sub-total (net transfer and net evaporation) na na na na Extractions Surety 1 0.2 0% -1% 0% Surety 2 0.0 na na na Surety 3 0.0 na na na Surety 4 0.0 na na na Surety 5 8.0 -1% -2% -2% Surety 6 0.3 -1% -1% -2% Surety 7 0.0 na na na Surety 8 0.0 na na na Unlicensed 2.7 -1% -6% -4% Sub-total (extractions) 11.2 -1% -3% -3% End-of-system (EOS) streamflow 308.0 -2% -5% -13% Total (outflows) 319.2 -2% -5% -13% na – not applicable (h) 29_Inglis-Flowerdale

A Cwet Cmid Cdry GL/y percent change relative to Scenario A Storage volume Mean annual change in volume na na na na Inflows From catchment runoff 362.6 -2% -5% -12% From flows downstream of hydro schemes na na na na Total (inflows) 362.6 -2% -5% -12% Outflows Net catchment transfers/losses (including storages if na na na na any) Net evaporation (evaporation – rainfall) from storages na na na na Sub-total (net transfer and net evaporation) na na na na Extractions Surety 1 0.5 0% -1% -1% Surety 2 0.0 na na na Surety 3 0.0 na na na Surety 4 0.0 na na na Surety 5 6.3 0% -1% -1% Surety 6 5.3 0% -2% -1% Surety 7 0.0 na na na Surety 8 0.0 na na na Unlicensed 1.0 0% -1% -1% Sub-total (extractions) 13.1 0% -1% -1% End-of-system (EOS) streamflow 349.5 -3% -5% -12% Total (outflows) 362.6 -2% -5% -12% na – not applicable

16 ▪ River modelling for Tasmania. Volume 1: the Arthur-Inglis-Cam region © CSIRO 2009

Table 5. Mean annual water balance for each catchment under scenarios A and C (continued)

(i) 30_Cam

A Cwet Cmid Cdry GL/y percent change relative to Scenario A Storage volume Mean annual change in volume na na na na Inflows From catchment runoff 160.0 -4% -7% -14% From flows downstream of hydro schemes na na na na Total (inflows) 160.0 -4% -7% -14% Outflows Net catchment transfers/losses (including storages if any) -8.1 6% 10% 19% Net evaporation (evaporation – rainfall) from storages na na na na Sub-total (net transfer and net evaporation) -8.1 6% 10% 19% Extractions Surety 1 1.4 0% 0% 0% Surety 2 0.0 na na na Surety 3 0.0 na na na Surety 4 0.0 na na na Surety 5 1.9 0% -2% -2% Surety 6 0.0 0% -1% -1% Surety 7 0.0 na na na Surety 8 0.0 na na na Unlicensed 0.9 0% -4% -3% Sub-total (extractions) 4.2 0% -2% -1% End-of-system (EOS) streamflow 163.9 -4% -7% -14% Total (outflows) 160.0 -3% -7% -14% na – not applicable (j) 31_Emu

A Cwet Cmid Cdry GL/y percent change relative to Scenario A Storage volume Mean annual change in volume 0.0 0% -5% -3% Inflows From catchment runoff 252.8 -4% -7% -12% From flows downstream of hydro schemes na na na na Total (inflows) 252.8 -4% -7% -12% Outflows Net catchment transfers/losses (including storages if 41.9 -4% -7% -12% any) Net evaporation (evaporation – rainfall) from storages -3.1 6% 12% 18% – Companion Reservoir + Pet Reservoir + Guide Reservoir + Talbots Lagoon Sub-total (net transfer and net evaporation) 38.8 -3% -6% -12% Extractions Surety 1 0.1 0% 0% 0% Surety 2 0.0 na na na Surety 3 0.0 na na na Surety 4 0.0 na na na Surety 5 30.4 0% -1% 0% Surety 6 0.1 0% -1% -1% Surety 7 0.0 na na na Surety 8 0.0 na na na Unlicensed 0.9 0% 0% 0% Sub-total (extractions) 31.5 0% -1% 0% End-of-system (EOS) streamflow 182.5 -4% -8% -14% Total (outflows) 252.8 -4% -7% -12% na – not applicable

Table 5. Mean annual water balance for each catchment under scenarios A and C (continued)

(k) 32_Blythe

A Cwet Cmid Cdry GL/y percent change relative to Scenario A Storage volume Mean annual change in volume na na na na Inflows From catchment runoff 261.7 -4% -7% -12% From flows downstream of hydro schemes na na na na Total (inflows) 261.7 -4% -7% -12% Outflows Net catchment transfers/losses (including storages if na na na na any) Net evaporation (evaporation – rainfall) from storages na na na na Sub-total (net transfer and net evaporation) na na na na Extractions Surety 1 0.2 0% 0% 0% Surety 2 0.0 na na na Surety 3 0.0 na na na Surety 4 0.0 na na na Surety 5 6.1 0% 0% -1% Surety 6 0.2 0% -1% -2% Surety 7 0.0 na na na Surety 8 0.0 na na na Unlicensed 0.4 0% 0% 0% Sub-total (extractions) 6.9 0% 0% -1% End-of-system (EOS) streamflow 254.8 -4% -7% -13% Total (outflows) 261.7 -4% -7% -12% na – not applicable

Figure 6 shows the mean annual streamflow for the major river reaches in each catchment under scenarios P, A and C where C range is defined by the upper and lower bounds of Scenario C streamflow. Generally this is defined by streamflow under scenarios Cwet and Cdry, but due to the way that the C scenarios are derived, occasionally Scenario Cmid may be used.

Other than in the Emu catchment, all the major rivers in the region are gaining reaches (where the flow in the river increases moving downstream). The flow in the Emu catchment decreases under scenarios A and C relative to Scenario P downstream of the point where Burnie Mill extractions from the river occur.

Up to a maximum of eight reporting locations were included for each major river reach. The number of reporting locations on a river is related to the number of modelled subcatchments on the river. In some catchments, there are less than eight reporting locations, as the largest river reach in the catchment is modelled by less than eight subcatchments. End-of-system (EOS) represents the total flow at the end of the catchment. In catchments where there is a major river and a number of smaller rivers, the EOS flow is the summation of the end-of-river flow for all rivers within the catchment.

The reporting locations are shown in Figure 3. The differences in the flows for Scenario P relative to Scenario A show the impact of extractions from the river. In many cases the flows for Scenario P are indistinguishable from Scenario A as there are relatively small extractions in the river.

On all the major rivers, river flows decrease or remain the same under Scenario C relative to Scenario A.

18 ▪ River modelling for Tasmania. Volume 1: the Arthur-Inglis-Cam region © CSIRO 2009

(a) 01_Flinders Island

200

. C range 150 Cmid A 100 P (GL)

50 Mean annual flow

0 EOS Reporting location

(b) 23_Arthur (Arthur River)

3000 C range . 2500 Cmid 2000 A . 1500 P (GL) 1000

Mean annualMean flow 500

0 1 2345678EOS Reporting location

90 80 C range . 70 Cmid 60 A . 50 P

(GL) 40 30 20 Mean annualMean flow 10 0 1 2 3 4 5 6 EOS Reporting location

(d) 25_King Island (Sea Elephant River)

250

. C range 200 Cmid A

. 150 P (GL) 100

50 Mean annualMean flow

0 1 2 3 EOS Reporting location

Figure 6. River transects showing streamflow under scenarios P, A and C

(e) 26_Montagu (Montagu River)

160 140 C range . 120 Cmid 100 A . 80 P (GL) 60 40 Mean annualMean flow 20 0 1 2 3 4 5 6 7 8 EOS Reporting location

(f) 27_Duck (Duck River)

300 C range . 250 Cmid 200 A . 150 P (GL) 100

Mean annualMean flow 50

0 1 2 3 4 5 6 EOS Reporting location

(g) 28_Black-Detention (Black River)

350 C range

. 300 Cmid 250 A

. 200 P

(GL) 150 100

Mean annualMean flow 50 0 1 2 3 4 5 6 7 8 EOS Reporting location

(h) 29_Inglis-Flowerdale (Flowerdale River)

400 350 C range . 300 Cmid 250 A . 200 P (GL) 150 100 Mean annualMean flow 50 0 1 234567EOS Reporting location

Figure 6. River transects showing streamflow under scenarios P, A and C (continued)

20 ▪ River modelling for Tasmania. Volume 1: the Arthur-Inglis-Cam region © CSIRO 2009

(i) 30_Cam (Cam River)

180 160 C range . 140 Cmid 120 A . 100 P

(GL) 80 60 40 Mean annualMean flow 20 0 1 2 3 4 5 6 EOS Reporting location

(j) 31_Emu (Emu River)

250 C range . 200 Cmid A

. 150 P

(GL) 100

50 Mean annualMean flow

0 1 2 3 4 5 6 7 8 EOS Reporting location

(k) 32_Blythe (Blythe River)

300 C range . 250 Cmid 200 A . 150 P (GL) 100

Mean annualMean flow 50

0 1 2 3 4 5 6 7 8 EOS Reporting location

Figure 6. River transects showing streamflow under scenarios P, A and C (continued)

A time series of annual total streamflow for the whole Arthur-Inglis-Cam region, represented as the total EOS flow, under Scenario A is shown in Figure 7a. EOS flow is defined as the total flow at the end of the catchment. In catchments where there is a major river and a number of smaller rivers, the EOS flow is the summation of the end of river flow for all rivers within the catchment.

There is a high level of variability in total streamflow between years, ranging from 2559 to 7947 GL/year, with a mean of 4690 GL/year. High flows are not as large or as frequent over the last 25 years, compared with the previous 59 years. Figure 7b–d shows the difference in annual total surface water under Scenario C relative to Scenario A. The annual total streamflow decreases in all but one year under Scenario Cwet relative to Scenario A, by up to 189 GL/year with a mean of 104 GL/year. The decrease in annual total streamflow under Scenario Cmid ranges from 120 to 391 GL/year with a mean of 244 GL/year. Under Scenario Cdry, the decrease in annual total streamflow ranges from 274 to 917 GL/year with a mean of 537 GL/year. The regional EOS flow is dominated by the Arthur catchment which accounts for over 50 percent of the regional EOS flow.

(a) Scenario A (b) Scenario Cwet 9000 200 . 8000 0 7000 6000 -200 5000 -400 4000 3000 -600 2000 -800 1000 Annual difference (GL) Annual EOS volume(GL) 0 -1000 0 20406080 0 20406080 Year Year

200 200 . 0 0

-200 -200

-400 -400

-600 -600

-800 -800 Annual difference (GL) Annual difference (GL) -1000 -1000 020406080 020406080 Year Year

Figure 7. End-of-system (EOS) streamflow in the Arthur-Inglis-Cam region under (a) Scenario A, and difference from Scenario A under scenarios (b) Cwet, (c) Cmid and (d) Cdry

3.2 Storage behaviour

The modelled behaviour of storages gives an indication of the level of regulation of a system, as well as how reliable the storage is during extended periods of low inflows. Details of the behaviour of each storage under scenarios A and C for the full 84-year model run can be seen in Table 6. The mean days between spills are unchanged under Scenario Cwet relative to Scenario A, whilst the maximum days between spills is slightly larger under Scenario Cwet relative to Scenario A. The mean and maximum days between spills are generally higher under Scenario Cwet relative to Scenario Cdry. All storages show a lower number of mean days between spills for Scenario Cdry relative to Scenario Cmid. This is partially due to storage operating rules, and partially a consequence of the method used for selection of the wet, mid and dry scenarios, as discussed in Section 3. The selection of Cwet, Cmid and Cdry scenarios was based on mean annual runoff and peak flows may actually be higher in some years under Scenario Cmid relative to Scenario Cwet, or Scenario Cdry relative to Scenario Cmid because different GCMs were used to define these scenarios and these GCMs may scale peak rainfalls by different amounts.

Time series of storage volume for a representative ten years are shown in Figure 8. These time series represent the modelled storage behaviour which included 2007 operating rules. The storage behaviour, therefore, is not necessarily representative of historical storage levels. All reservoirs are generally drawn down to lower volumes under Scenario C relative to Scenario A, however, these differences are minor. All storages spill each year. This is consistent with Scenario Cmid having a higher mean number of days between spills than either scenarios Cdry or Cwet.

22 ▪ River modelling for Tasmania. Volume 1: the Arthur-Inglis-Cam region © CSIRO 2009

Table 6. Storage behaviour under scenarios A and C

A Cwet Cmid Cdry Companion Reservoir Minimum storage volume (GL) 0 0 0 0 Mean days between spills 41 41 53 42 Maximum days between spills 192 195 203 201 Guide Reservoir Minimum storage volume (GL) 0 0 0 0 Mean days between spills 47 47 54 51 Maximum days between spills 275 281 290 319 Lake Mikany Minimum storage volume (GL) 1 1 1 1 Mean days between spills 29 29 33 31 Maximum days between spills 261 292 293 301 Pet Reservoir Minimum storage volume (GL) 1 0 0 0 Mean days between spills 62 63 75 72 Maximum days between spills 307 328 346 361 Talbots Lagoon Minimum storage volume (GL) 0 0 0 0 Mean days between spills 29 29 36 32 Maximum days between spills 255 255 255 257

(a) Companion Reservoir (b) Guide Reservoir

1.6 2.0 1.4

. 1.2 . 1.5 1.0 0.8 1.0 0.6 C range Volume (GL) Volume (GL) 0.4 Volume (GL) 0.5 Volume (GL) Cmid 0.2 A 0.0 0.0 15 16 17 18 19 20 21 22 23 24 15 16 17 18 19 20 21 22 23 24 Year Year C range A Cmid

3.0 3.0 2.5 2.5 . . 2.0 2.0 1.5 1.5 1.0 C range 1.0 C range Volume (GL) Volume (GL) Volume (GL) 0.5 Cmid Volume (GL) 0.5 Cmid A A 0.0 0.0 15 16 17 18 19 20 21 22 23 24 15 16 17 18 19 20 21 22 23 24 Year Year

(e) Talbots Lagoon

3.0 2.5 . 2.0 1.5 1.0 C range Volume (GL) Volume (GL) Cmid 0.5 A 0.0 15 16 17 18 19 20 21 22 23 24 Year

Figure 8. Storage behaviour over representative ten-year period under scenarios A and C

3.3 Consumptive water use

Consumptive water use includes both the licensed and unlicensed extractions from the river system. The modelling of extractions is described in Section 2.1. Time series of annual extractions for Scenario A are shown in Figure 9. Total annual extractions for the region vary from a minimum of 86 to a maximum of 97 GL/year over the 84 years. The differences in annual extractions under Scenario C are also shown in Figure 9. Under Scenario Cwet, there are nine years where extractions increase when compared to Scenario A. Extractions are lower in every year under scenarios Cmid and Cdry relative to Scenario A. The mean annual reductions in extractions under scenarios Cwet, Cmid and Cdry relative to Scenario A are 0.2, 1.2 and 1.2 GL/year respectively. These reductions are relatively small in comparison to the mean annual extraction of 93 GL/year under Scenario A. The reductions in extraction volumes are spread over a range of sureties, representing a reduction in both summer and winter extractions.

24 ▪ River modelling for Tasmania. Volume 1: the Arthur-Inglis-Cam region © CSIRO 2009

(a) Scenario A (b) Scenario Cwet

. 120 0.5 . 100 0.0 -0.5 80

. -1.0 60 -1.5 (GL) (GL) -2.0 40 -2.5 20 -3.0 Annual difference (GL) Annual extraction volume 0 -3.5 0 20406080 020406080 Year Year

0.5 0.5 . . 0.0 0.0 -0.5 -0.5 -1.0 -1.0 -1.5 -1.5 -2.0 -2.0 -2.5 -2.5 -3.0 -3.0 Annual difference (GL) Annual difference (GL) -3.5 -3.5 0 20406080 0 20406080 Year Year

Figure 9. Total annual extractions for Arthur-Inglis-Cam region under (a) Scenario A, and difference from Scenario A under scenarios (b) Cwet, (c) Cmid and (d) Cdry

Table 7 shows the mean annual volume of allocated and extracted water in each catchment in the region under scenarios A and C. In the majority of catchments, the amount of water extracted is equal to or only slightly less than that allocated. The exception is the Black-Detention catchment, where the mean extractions are 85 percent of the allocation under Scenario A. There is very little change in the mean allocated or extracted volumes for all catchments under Scenario C relative to Scenario A.

Table 7. Allocated and extracted mean annual flows for catchments under scenarios A and C

A Cwet Cmid Cdry GL/y 01_Flinders Island Allocated water 2.1 2.1 2.1 2.1 Extraction 1.9 1.9 1.9 1.9 Difference 0.2 0.2 0.2 0.2 23_Arthur Allocated water 4.9 4.9 4.9 4.9 Extraction 4.9 4.9 4.9 4.9 Difference 0.0 0.0 0.0 0.0 24_Welcome Allocated water 0.4 0.4 0.4 0.4 Extraction 0.4 0.4 0.4 0.4 Difference 0.0 0.0 0.0 0.0 25_King Island Allocated water 3.8 3.8 3.8 3.8 Extraction 3.8 3.8 3.8 3.7 Difference 0.1 0.1 0.1 0.1 26_Montagu Allocated water 1.9 1.9 1.9 1.9 Extraction 1.9 1.9 1.8 1.8 Difference 0.1 0.1 0.1 0.1 27_Duck Allocated water 12.9 12.8 12.7 12.6 Extraction 12.8 12.8 12.6 12.5 Difference 0.1 0.1 0.1 0.1 28_Black-Detention Allocated water 13.1 13.1 13.0 13.0 Extraction 11.2 11.1 10.9 10.9 Difference 1.9 1.9 2.1 2.1 29_Inglis-Flowerdale Allocated water 13.5 13.5 13.4 13.4 Extraction 13.1 13.1 12.9 13.0 Difference 0.4 0.4 0.5 0.4 30_Cam Allocated water 4.7 4.7 4.7 4.7 Extraction 4.2 4.2 4.1 4.1 Difference 0.5 0.5 0.6 0.5 31_Emu Allocated water 31.8 31.8 31.8 31.8 Extraction 31.5 31.5 31.2 31.3 Difference 0.3 0.3 0.5 0.4 32_Blythe Allocated water 7.0 7.0 7.0 7.0 Extraction 6.9 6.9 6.9 6.9 Difference 0.1 0.1 0.1 0.1

The mean annual reliability of high and low priority extractions is shown in Table 8 for each catchment as fraction extracted per unit of water allocated. The reliabilities of extractions over summer and winter are shown in Table 9 and Table 10 respectively. The annual reliability of high priority extractions is 98 percent or greater under all scenarios for all catchments except Flinders Island, where the reliability of high priority extractions is 88 percent or greater. In summer, the reliability of high priority extractions in Flinders Island and Black-Detention catchments is slightly lower than the reliability of annual extractions. The reliability of low priority extractions is greater than 96 percent under all scenarios for the majority of catchments, with the exception of Flinders Island, Cam and Black-Detention catchments. In these catchments, the reliability of low priority extractions is lower in summer when compared to winter and annual reliability.

26 ▪ River modelling for Tasmania. Volume 1: the Arthur-Inglis-Cam region © CSIRO 2009

The reliability of extractions changes by less than 2 percent in all catchments for both high and low priority extractions under Scenario C relative to Scenario A on an annual and seasonal basis.

The reliability of high priority extractions may be less than the reliability of low priority extractions, as these extractions may be taken over different months of the year. For example, a licence for high priority extractions for town water supply may apply year-round, whereas a licence for a low priority allocation may be for opportunistic extractions of peak flood waters over winter.

Table 8. Mean reliability of high and low priority annual allocations for catchments under scenarios A and C (annual)

A Cwet Cmid Cdry fraction extracted per unit allocated 01_Flinders Island High priority (surety 1 to 4) 0.89 0.89 0.88 0.88 Low priority (surety 5 to 8 & unlicensed) 0.92 0.92 0.91 0.90 23_Arthur High priority (surety 1 to 4) 1.00 1.00 1.00 1.00 Low priority (surety 5 to 8 & unlicensed) 1.00 1.00 1.00 1.00 24_Welcome High priority (surety 1 to 4) - - - - Low priority (surety 5 to 8 & unlicensed) 1.00 1.00 1.00 1.00 25_King Island High priority (surety 1 to 4) 0.99 0.99 0.99 0.99 Low priority (surety 5 to 8 & unlicensed) 0.98 0.98 0.98 0.97 26_Montagu High priority (surety 1 to 4) 1.00 1.00 0.99 1.00 Low priority (surety 5 to 8 & unlicensed) 0.97 0.97 0.97 0.96 27_Duck High priority (surety 1 to 4) 1.00 1.00 1.00 1.00 Low priority (surety 5 to 8 & unlicensed) 0.99 0.99 0.99 0.99 28_Black-Detention High priority (surety 1 to 4) 0.99 0.98 0.98 0.98 Low priority (surety 5 to 8 & unlicensed) 0.85 0.85 0.84 0.84 29_Inglis-Flowerdale High priority (surety 1 to 4) 1.00 1.00 1.00 1.00 Low priority (surety 5 to 8 & unlicensed) 0.97 0.97 0.96 0.97 30_Cam High priority (surety 1 to 4) 1.00 0.99 0.99 0.99 Low priority (surety 5 to 8 & unlicensed) 0.85 0.85 0.83 0.84 31_Emu High priority (surety 1 to 4) 1.00 1.00 1.00 1.00 Low priority (surety 5 to 8 & unlicensed) 0.99 0.99 0.98 0.99 32_Blythe High priority (surety 1 to 4) 1.00 1.00 1.00 1.00 Low priority (surety 5 to 8 & unlicensed) 0.99 0.99 0.98 0.98

Table 9. Mean reliability of high and low priority allocations under scenarios A and C (summer – October to March inclusive)

A Cwet Cmid Cdry fraction extracted per unit allocated 01_Flinders Island High priority (surety 1 to 4) 0.85 0.85 0.84 0.85 Low priority (surety 5 to 8 & unlicensed) 0.85 0.85 0.84 0.84 23_Arthur High priority (surety 1 to 4) 1.00 1.00 1.00 1.00 Low priority (surety 5 to 8 & unlicensed) 1.00 1.00 1.00 1.00 24_Welcome High priority (surety 1 to 4) - - - - Low priority (surety 5 to 8 & unlicensed) 1.00 1.00 1.00 1.00 25_King Island High priority (surety 1 to 4) 0.99 0.99 0.99 0.99 Low priority (surety 5 to 8 & unlicensed) 0.97 0.96 0.95 0.96 26_Montagu High priority (surety 1 to 4) 1.00 1.00 0.99 1.00 Low priority (surety 5 to 8 & unlicensed) 0.94 0.94 0.93 0.93 27_Duck High priority (surety 1 to 4) 1.00 1.00 1.00 1.00 Low priority (surety 5 to 8 & unlicensed) 0.99 0.99 0.99 0.99 28_Black-Detention High priority (surety 1 to 4) 0.96 0.96 0.95 0.96 Low priority (surety 5 to 8 & unlicensed) 0.78 0.77 0.75 0.75 29_Inglis-Flowerdale High priority (surety 1 to 4) 1.00 1.00 1.00 1.00 Low priority (surety 5 to 8 & unlicensed) 0.96 0.96 0.95 0.96 30_Cam High priority (surety 1 to 4) 0.99 0.99 0.99 0.99 Low priority (surety 5 to 8 & unlicensed) 0.79 0.79 0.76 0.77 31_Emu High priority (surety 1 to 4) 1.00 1.00 1.00 1.00 Low priority (surety 5 to 8 & unlicensed) 0.99 0.99 0.98 0.99 32_Blythe High priority (surety 1 to 4) 1.00 1.00 1.00 1.00 Low priority (surety 5 to 8 & unlicensed) 1.00 1.00 1.00 1.00

28 ▪ River modelling for Tasmania. Volume 1: the Arthur-Inglis-Cam region © CSIRO 2009

Table 10. Mean reliability of high and low priority allocations under scenarios A and C (winter – April to September inclusive)

A Cwet Cmid Cdry fraction extracted per unit allocated 01_Flinders Island High priority (surety 1 to 4) 0.93 0.93 0.93 0.92 Low priority (surety 5 to 8 & unlicensed) 0.93 0.93 0.93 0.92 23_Arthur High priority (surety 1 to 4) 1.00 1.00 1.00 1.00 Low priority (surety 5 to 8 & unlicensed) 1.00 1.00 1.00 1.00 24_Welcome High priority (surety 1 to 4) - - - - Low priority (surety 5 to 8 & unlicensed) 1.00 1.00 1.00 1.00 25_King Island High priority (surety 1 to 4) 0.98 0.98 0.97 0.97 Low priority (surety 5 to 8 & unlicensed) 0.98 0.98 0.98 0.97 26_Montagu High priority (surety 1 to 4) 1.00 1.00 1.00 1.00 Low priority (surety 5 to 8 & unlicensed) 0.99 0.99 0.98 0.98 27_Duck High priority (surety 1 to 4) 1.00 1.00 1.00 1.00 Low priority (surety 5 to 8 & unlicensed) 0.99 0.99 0.99 0.99 28_Black-Detention High priority (surety 1 to 4) 0.99 0.99 0.99 0.98 Low priority (surety 5 to 8 & unlicensed) 0.93 0.92 0.92 0.91 29_Inglis-Flowerdale High priority (surety 1 to 4) 1.00 1.00 1.00 1.00 Low priority (surety 5 to 8 & unlicensed) 0.98 0.98 0.98 0.98 30_Cam High priority (surety 1 to 4) 1.00 1.00 1.00 1.00 Low priority (surety 5 to 8 & unlicensed) 0.93 0.93 0.92 0.92 31_Emu High priority (surety 1 to 4) 1.00 1.00 1.00 1.00 Low priority (surety 5 to 8 & unlicensed) 0.99 0.99 0.99 0.99 32_Blythe High priority (surety 1 to 4) 1.00 1.00 1.00 1.00 Low priority (surety 5 to 8 & unlicensed) 0.98 0.98 0.98 0.98

Figure 10 shows the allocation and extraction reliability as percentage of years for exceedance of a given volume. The allocation volume is not constant each year in some catchments due to regulations which restrict allocations under low flow conditions (see Table 4). There is a slight reduction in extractions under Scenario C relative to Scenario A in some catchments. The impact of future climate on extractions is small due to the low level of extractions in the region. Figure 11 shows the same figures for summer only. Summer extractions are less reliable than annual extractions in all catchments except Arthur and Welcome where they remain unchanged, and Cam catchment where the reliability of summer extractions is greater than the reliability of annual extractions.

In the Flinders Island, Montagu, Black-Detention and Cam catchments, the extracted water volume does not meet the allocated water volume in any year, reflecting the fact that water is not consistently available for extraction in these catchments. In the absence of other information, the methodology used in the modelling assumes that irrigators are attempting to extract water at a constant rate over the allocation period. In reality, irrigators will extract water opportunistically as it is available, which is likely to result in a higher reliability of extraction than the modelled results. In the Arthur and Welcome catchments, the extracted water volume is equal to the allocated water volume for all years except one in the Welcome catchment.

(a-1) 01_Flinders Island – allocated water (a-2) 01_Flinders Island – extracted per allocated

2.5 1.0 0.9 . 2.0 0.8

. 0.7 1.5 0.6 0.5 1.0 0.4 C range 0.3 C range

0.5 Cmid unit allocated 0.2 Cmid Annual volume (GL) A Extracted volumeper 0.1 A 0.0 0.0 0% 20% 40% 60% 80% 100% 0% 20% 40% 60% 80% 100% Percent of years exceeded Percent of years exceeded

(b-1) 23_Arthur – allocated water (b-2) 23_Arthur – extracted per allocated

5.0 1.0 4.8 0.9 . 4.6 0.8

4.4 . 0.7 4.2 0.6 4.0 0.5 3.8 0.4 3.6 C range 0.3 C range

3.4 Cmid unit allocated 0.2 Cmid Annual volume (GL) A 3.2 Extracted volumeper 0.1 A 3.0 0.0 0% 20% 40% 60% 80% 100% 0% 20% 40% 60% 80% 100% Percent of years exceeded Percent of years exceeded

(c-1) 24_Welcome – allocated water (c-2) 24_Welcome – extracted per allocated

0.40 1.0 0.35 0.9 . 0.8 0.30

. 0.7 0.25 0.6 0.20 0.5 0.15 0.4 C range 0.3 C range 0.10 Cmid unit allocated 0.2 Cmid Annual volume (GL) 0.05 A Extracted volumeper 0.1 A 0.00 0.0 0% 20% 40% 60% 80% 100% 0% 20% 40% 60% 80% 100% Percent of years exceeded Percent of years exceeded

(d-1) 25_King Island – allocated water (d-2) 25_King Island – extracted per allocated

4.0 1.0 3.5 0.9 . 0.8 3.0

. 0.7 2.5 0.6 2.0 0.5 1.5 0.4 C range 0.3 C range 1.0 Cmid unit allocated 0.2 Cmid Annual volume (GL) 0.5 A Extracted volumeper 0.1 A 0.0 0.0 0% 20% 40% 60% 80% 100% 0% 20% 40% 60% 80% 100% Percent of years exceeded Percent of years exceeded

Figure 10. Allocation and extraction reliability for catchments under scenarios A and C (annual)

30 ▪ River modelling for Tasmania. Volume 1: the Arthur-Inglis-Cam region © CSIRO 2009

(e-1) 26_Montagu – allocated water (e-2) 26_Montagu – extracted per allocated

2.5 1.0 0.9 . 2.0 0.8

. 0.7 1.5 0.6 0.5 1.0 0.4 C range 0.3 C range

0.5 Cmid unit allocated 0.2 Cmid Annual volume (GL) A Extracted volumeper 0.1 A 0.0 0.0 0% 20% 40% 60% 80% 100% 0% 20% 40% 60% 80% 100% Percent of years exceeded Percent of years exceeded

(f-1) 27_Duck – allocated water (f-2) 27_Duck – extracted per allocated

16 1.0 14 0.9 . 0.8 12

. 0.7 10 0.6 8 0.5 6 0.4 C range 0.3 C range 4 Cmid unit allocated 0.2 Cmid Annual volume (GL) 2 A Extracted volumeper 0.1 A 0 0.0 0% 20% 40% 60% 80% 100% 0% 20% 40% 60% 80% 100% Percent of years exceeded Percent of years exceeded

(g-1) 28_Black-Detention – allocated water (g-2) 28_Black-Detention – extracted per allocated

16 1.0 14 0.9 . 0.8 12

(h-1) 29_Inglis-Flowerdale – allocated water (h-2) 29_Inglis-Flowerdale – extracted per allocated

16 1.0 14 0.9 . 0.8 12

Figure 10. Allocation and extraction reliability for catchments under scenarios A and C (annual) (continued)

(i-1) 30_Cam – allocated water (i-2) 30_Cam – extracted per allocated

6 1.0 0.9 . 5 0.8

4 . 0.7 0.6 3 0.5 0.4 2 C range 0.3 C range

Cmid unit allocated 0.2 Cmid Annual volume (GL) 1 A Extracted volumeper 0.1 A 0 0.0 0% 20% 40% 60% 80% 100% 0% 20% 40% 60% 80% 100% Percent of years exceeded Percent of years exceeded

(j-1) 31_Emu – allocated water (j-2) 31_Emu – extracted per allocated

35 1.0 0.9

. 30 0.8 25 . 0.7 20 0.6 0.5 15 0.4 10 C range 0.3 C range

Cmid unit allocated 0.2 Cmid Annual volume (GL) 5 A Extracted volumeper 0.1 A 0 0.0 0% 20% 40% 60% 80% 100% 0% 20% 40% 60% 80% 100% Percent of years exceeded Percent of years exceeded

(k-1) 32_Blythe – allocated water (k-2) 32_Blythe – extracted per allocated

8 1.0 7 0.9 . 0.8 6

. 0.7 5 0.6 4 0.5 3 0.4 C range 0.3 C range 2 Cmid unit allocated 0.2 Cmid Annual volume (GL) 1 A Extracted volumeper 0.1 A 0 0.0 0% 20% 40% 60% 80% 100% 0% 20% 40% 60% 80% 100% Percent of years exceeded Percent of years exceeded

Figure 10. Allocation and extraction reliability for catchments under scenarios A and C (annual) (continued)

32 ▪ River modelling for Tasmania. Volume 1: the Arthur-Inglis-Cam region © CSIRO 2009

(a-1) 01_Flinders Island – allocated water (a-2) 01_Flinders Island – extracted per allocated

2.5 1.0 0.9

. C range 2.0 Cmid 0.8

A . 0.7 1.5 0.6 0.5 1.0 0.4 0.3 C range 0.5 unit allocated 0.2 Cmid Summervolume (GL)

Extracted volumeper 0.1 A 0.0 0.0 0% 20% 40% 60% 80% 100% 0% 20% 40% 60% 80% 100% Percent of years exceeded Percent of years exceeded

(b-1) 23_Arthur – allocated water (b-2) 23_Arthur – extracted per allocated

5.0 1.0 4.8 0.9

. C range 4.6 Cmid 0.8

4.4 A . 0.7 4.2 0.6 4.0 0.5 3.8 0.4 3.6 0.3 C range 3.4 unit allocated 0.2 Cmid Summer volume (GL)

3.2 Extracted volumeper 0.1 A 3.0 0.0 0% 20% 40% 60% 80% 100% 0% 20% 40% 60% 80% 100% Percent of years exceeded Percent of years exceeded

(c-1) 24_Welcome – allocated water (c-2) 24_Welcome – extracted per allocated

0.40 1.0 0.9

. 0.35 C range 0.8 0.30 Cmid A . 0.7 0.25 0.6 0.20 0.5 0.15 0.4 0.3 C range 0.10 unit allocated 0.2 Cmid Summer volume (GL) 0.05 Extracted volumeper 0.1 A 0.00 0.0 0% 20% 40% 60% 80% 100% 0% 20% 40% 60% 80% 100% Percent of years exceeded Percent of years exceeded

(d-1) 25_King Island – allocated water (d-2) 25_King Island – extracted per allocated

4.0 1.0 0.9

. 3.5 C range 0.8 3.0 Cmid A . 0.7 2.5 0.6 2.0 0.5 1.5 0.4 0.3 C range 1.0 unit allocated 0.2 Cmid Summer volume (GL) 0.5 Extracted volumeper 0.1 A 0.0 0.0 0% 20% 40% 60% 80% 100% 0% 20% 40% 60% 80% 100% Percent of years exceeded Percent of years exceeded

Figure 11. Allocation and extraction for catchments reliability under scenarios A and C (summer – October to March inclusive)

(e-1) 26_Montagu – allocated water (e-2) 26_Montagu – extracted per allocated

2.5 1.0 0.9

. C range 2.0 Cmid 0.8

A . 0.7 1.5 0.6 0.5 1.0 0.4 0.3 C range 0.5 unit allocated 0.2 Cmid Summervolume (GL)

Extracted volumeper 0.1 A 0.0 0.0 0% 20% 40% 60% 80% 100% 0% 20% 40% 60% 80% 100% Percent of years exceeded Percent of years exceeded

(f-1) 27_Duck – allocated water (f-2) 27_Duck – extracted per allocated

16 1.0 0.9 . 14 C range 0.8 12 Cmid A . 0.7 10 0.6 8 0.5 6 0.4 0.3 C range 4 unit allocated 0.2 Cmid Summer volume(GL) 2 Extracted volumeper 0.1 A 0 0.0 0% 20% 40% 60% 80% 100% 0% 20% 40% 60% 80% 100% Percent of years exceeded Percent of years exceeded

(g-1) 28_Black-Detention – allocated water (g-2) 28_Black-Detention – extracted per allocated

(h-1) 29_Inglis-Flowerdale – allocated water (h-2) 29_Inglis-Flowerdale – extracted per allocated

Figure 11. Allocation and extraction for catchments reliability under scenarios A and C (summer – October to March inclusive) (continued)

34 ▪ River modelling for Tasmania. Volume 1: the Arthur-Inglis-Cam region © CSIRO 2009

(i-1) 30_Cam – allocated water (i-2) 30_Cam – extracted per allocated

6 1.0 0.9 . C range 5 Cmid 0.8 4 A . 0.7 0.6 3 0.5 0.4 2 0.3 C range unit allocated 0.2 Cmid

Summer volume (GL) 1

Extracted volumeper 0.1 A 0 0.0 0% 20% 40% 60% 80% 100% 0% 20% 40% 60% 80% 100% Percent of years exceeded Percent of years exceeded

(j-1) 31_Emu – allocated water (j-2) 31_Emu – extracted per allocated

35 1.0 0.9 . 30 C range Cmid 0.8

25 A . 0.7 20 0.6 0.5 15 0.4 10 0.3 C range unit allocated 0.2 Cmid Summer volume(GL) 5 Extracted volumeper 0.1 A 0 0.0 0% 20% 40% 60% 80% 100% 0% 20% 40% 60% 80% 100% Percent of years exceeded Percent of years exceeded

(k-1) 32_Blythe – allocated water (k-2) 32_Blythe – extracted per allocated

8 1.0 0.9 . 7 C range 0.8 6 Cmid A . 0.7 5 0.6 4 0.5 3 0.4 0.3 C range 2 unit allocated 0.2 Cmid Summer volume(GL) 1 Extracted volumeper 0.1 A 0 0.0 0% 20% 40% 60% 80% 100% 0% 20% 40% 60% 80% 100% Percent of years exceeded Percent of years exceeded

Figure 11. Allocation and extraction for catchments reliability under scenarios A and C (summer – October to March inclusive) (continued)

The mean annual volume of extracted water for the lowest one-, three- and five-year periods under Scenario A, and the percentage change under Scenario C relative to Scenario A are shown in Table 11. These figures indicate the impact on water use during dry periods. In the majority of catchments, there is less than a 5 percent change in extracted water during dry periods under Scenario C. The exceptions are in the Montagu, Duck, Cam and Black-Detention catchments where there is greater than 5 percent change under Scenario Cdry for the lowest one-year period of extraction. The greatest change is in the Black-Detention catchment which shows a reduction of 7.1 percent in the volume of water extracted for the lowest one-year period of extraction under Scenario Cdry. Extraction volumes show a greater reduction during dry periods under Scenario C relative to Scenario A when compared to changes in the long-term mean extractions, indicating that the ability to extract water will be reduced in drier periods under future climate.

Table 11. Indicators of use during dry periods for catchments under Scenarios A and change under Scenario C relative to Scenario A

A Cwet Cmid Cdry GL/y percent change relative to Scenario A 01_Flinders Island Lowest 1-year period of extraction 1.6 0.6% 0.0% -3.8% Lowest 3-year period of extraction 1.7 0.2% 0.0% -2.1% Lowest 5-year period of extraction 1.8 0.1% -0.2% -1.7% Mean annual extraction for 84 years 1.9 0.0% -0.3% -1.3% 23_Arthur Lowest 1-year period of extraction 4.9 0.0% 0.0% 0.0% Lowest 3-year period of extraction 4.9 0.0% 0.0% 0.0% Lowest 5-year period of extraction 4.9 0.0% 0.0% 0.0% Mean annual extraction for 84 years 4.9 0.0% 0.0% 0.0% 24_Welcome Lowest 1-year period of extraction 0.3 0.0% 0.0% 0.0% Lowest 3-year period of extraction 0.4 -0.9% -1.9% -1.9% Lowest 5-year period of extraction 0.4 -0.6% -1.7% -1.1% Mean annual extraction for 84 years 0.4 -0.3% -0.8% -0.6% 25_King Island Lowest 1-year period of extraction 3.4 -1.5% -2.9% -4.7% Lowest 3-year period of extraction 3.6 -0.9% -2.0% -2.7% Lowest 5-year period of extraction 3.6 -0.7% -1.5% -2.0% Mean annual extraction for 84 years 3.8 -0.3% -0.7% -1.0% 26_Montagu Lowest 1-year period of extraction 1.7 -2.4% -4.8% -5.5% Lowest 3-year period of extraction 1.8 -1.5% -3.0% -3.8% Lowest 5-year period of extraction 1.8 -1.0% -2.4% -3.0% Mean annual extraction for 84 years 1.9 -0.7% -2.1% -2.2% 27_Duck Lowest 1-year period of extraction 10.8 -1.3% -3.4% -6.5% Lowest 3-year period of extraction 11.6 -2.0% -3.8% -5.3% Lowest 5-year period of extraction 12.2 -1.3% -3.0% -4.4% Mean annual extraction for 84 years 12.8 -0.6% -2.1% -2.5% 28_Black-Detention Lowest 1-year period of extraction 9.3 -2.8% -5.3% -7.1% Lowest 3-year period of extraction 10.0 -1.6% -3.8% -4.4% Lowest 5-year period of extraction 10.3 -1.0% -3.4% -3.6% Mean annual extraction for 84 years 11.2 -0.7% -2.7% -2.7% 29_Inglis-Flowerdale Lowest 1-year period of extraction 11.6 -0.5% -2.1% -0.9% Lowest 3-year period of extraction 12.3 -1.2% -3.4% -2.9% Lowest 5-year period of extraction 12.5 -0.8% -2.6% -2.1% Mean annual extraction for 84 years 13.1 -0.3% -1.4% -0.9% 30_Cam Lowest 1-year period of extraction 3.7 -1.9% -4.6% -5.1% Lowest 3-year period of extraction 3.8 -0.9% -3.3% -3.0% Lowest 5-year period of extraction 3.9 -0.6% -2.8% -2.2% Mean annual extraction for 84 years 4.2 -0.1% -1.9% -1.3% 31_Emu Lowest 1-year period of extraction 28.8 -0.7% -2.0% -1.5% Lowest 3-year period of extraction 30.3 -0.4% -1.7% -1.2% Lowest 5-year period of extraction 30.8 -0.2% -1.3% -0.7% Mean annual extraction for 84 years 31.5 -0.1% -0.8% -0.4% 32_Blythe Lowest 1-year period of extraction 6.3 -0.3% -0.9% -1.3% Lowest 3-year period of extraction 6.7 -0.1% -0.6% -1.1% Lowest 5-year period of extraction 6.7 -0.2% -0.6% -0.9% Mean annual extraction for 84 years 6.9 -0.1% -0.4% -0.5%

36 ▪ River modelling for Tasmania. Volume 1: the Arthur-Inglis-Cam region © CSIRO 2009

3.4 End-of-system river flow

The EOS monthly streamflow and daily duration curves for each catchment are shown in Figure 12 for scenarios P, A and C. Scenario P represents current infrastructure with no extractions under historical climate. In the majority of catchments, the shape of the flow duration curve is consistent under all scenarios. The exception to this is the Emu catchment, where the impact of diversions from the catchment can be seen under low flows resulting in a drop in flow volumes under scenarios A and C relative to Scenario P. A reduction in low flow volumes is observed in all catchments under Scenario C relative to Scenario A.

The monthly flow curves show a strong seasonal distribution of flows, with highest flows occurring in winter months. The mean monthly flow is generally reduced in all catchments under Scenario C relative to Scenario A in all months except for July and August. In all catchments, July and August EOS flows under Scenario Cmid are greater than those under scenarios Cwet and Cdry. This occurs as a result of the methodology used to select scenarios Cwet, Cdry and Cmid (as discussed in Section 3) as selection of scenarios was based on mean annual runoff, and did not take into account the seasonal distribution of flows.

(a-1) 01_Flinders Island – monthly flow (a-2) 01_Flinders Island – daily flow duration

1.2 100000

. C range C range

1.0 . Cmid 10000 Cmid A 0.8 A P 1000 P 0.6 100 0.4 10 0.2 EOS dailyflow (ML) EOS monthly flow (GL) 0.0 1 JFMAMJJASOND 0 20406080100 Month Percent time volume is exceeded

(b-1) 23_Arthur – monthly flow (b-2) 23_Arthur – daily flow duration

16 100000

. 14 C range . 10000 12 Cmid A 10 P 1000 8 100 C range 6 Cmid 4 10 A 2 P EOS dailyflow (ML) EOS monthly flow (GL) 0 1 JFMAMJ JASOND 0 20406080100 Month Percent time volume is exceeded

(c-1) 24_Welcome – monthly flow (c-2) 24_Welcome – daily flow duration

0.6 100000

. C range C range

0.5 . Cmid 10000 Cmid A 0.4 A P 1000 P 0.3 100 0.2 10 0.1 EOS dailyflow (ML) EOS monthly flow (GL) 0.0 1 JFMAMJJASOND 0 20406080100 Month Percent time volume is exceeded

Figure 12. Mean monthly end-of-system flow under and daily flow duration curves under scenarios P, A and C

(d-1) 25_King Island – monthly flow (d-2) 25_King Island – daily flow duration

1.8 100000

. 1.6 C range C range 1.4 Cmid . 10000 Cmid A 1.2 A 1000 P 1.0 P 0.8 100 0.6 0.4 10

0.2 EOS dailyflow (ML) EOS monthly flow (GL) 0.0 1 JFMAMJJASOND 0 20406080100 Month Percent time volume is exceeded

(e-1) 26_Montagu – monthly flow (e-2) 26_Montagu – daily flow duration

1.0 100000

. C range C range 0.8 Cmid . 10000 Cmid A A 0.6 P 1000 P

0.4 100

0.2 10 EOS dailyflow (ML) EOS monthly flow (GL) 0.0 1 JFMAMJJASOND 0 20406080100 Month Percent time volume is exceeded

(f-1) 27_Duck – monthly flow (f-2) 27_Duck – daily flow duration

1.8 100000

. 1.6 C range C range 1.4 Cmid . 10000 Cmid A 1.2 A 1000 P 1.0 P 0.8 100 0.6 0.4 10

0.2 EOS dailyflow (ML) EOS monthly flow (GL) 0.0 1 JFMAMJJASOND 0 20406080100 Month Percent time volume is exceeded

(g-1) 28_Black-Detention – monthly flow (g-2) 28_Black-Detention – daily flow duration

2.5 100000

. C range C range 2.0 Cmid . 10000 Cmid A A 1.5 P 1000 P

1.0 100

0.5 10 EOS dailyflow (ML) EOS monthly flow (GL) 0.0 1 JFMAMJJASOND 0 20406080100 Month Percent time volume is exceeded

Figure 12. Mean monthly end-of-system flow under and daily flow duration curves under scenarios P, A and C (continued)

38 ▪ River modelling for Tasmania. Volume 1: the Arthur-Inglis-Cam region © CSIRO 2009

(h-1) 29_Inglis-Flowerdale – monthly flow (h-2) 29_Inglis-Flowerdale – daily flow duration

2.5 100000

. C range C range 2.0 Cmid . 10000 Cmid A A 1.5 P 1000 P

1.0 100

0.5 10 EOS dailyflow (ML) EOS monthly flow (GL) 0.0 1 JFMAMJJASOND 0 20406080100 Month Percent time volume is exceeded

(i-1) 30_Cam – monthly flow (i-2) 30_Cam – daily flow duration

1.2 100000

. C range C range

1.0 . Cmid 10000 Cmid A 0.8 A P 1000 P 0.6 100 0.4 10 0.2 EOS dailyflow (ML) EOS monthly flow (GL) 0.0 1 JFMAMJJASOND 0 20406080100 Month Percent time volume is exceeded

(j-1) 31_Emu – monthly flow (j-2) 31_Emu – daily flow duration

1.4 100000 . 1.2 C range C range Cmid . 10000 Cmid 1.0 A A 0.8 P 1000 P

0.6 100 0.4 10 0.2 EOS dailyflow (ML) EOS monthly flow (GL) 0.0 1 JFMAMJJASOND 0 20406080100 Month Percent time volume is exceeded

(k-1) 32_Blythe – monthly flow (k-2) 32_Blythe – daily flow duration

1.8 100000

. 1.6 C range C range 1.4 Cmid . 10000 Cmid A 1.2 A 1000 P 1.0 P 0.8 100 0.6 0.4 10

0.2 EOS dailyflow (ML) EOS monthly flow (GL) 0.0 1 JFMAMJJASOND 0 20406080100 Month Percent time volume is exceeded

Figure 12. Mean monthly end-of-system flow under and daily flow duration curves under scenarios P, A and C (continued)

EOS daily peak flows for return periods of two, five and ten years are shown in Table 12 under scenarios A and P with changes under Scenario C relative to Scenario A. Peak flows were determined based on the procedure used in the Murray-Darling Basin Sustainable Yields Project (CSIRO, 2008) using a partial series analysis and a plotting position assigned based on rank. Scenario P represents streamflow modelled with historical climate, current infrastructure and no extractions taken from the river, allowing the impact of extractions to be explicitly considered by comparison to Scenario A. Peak flows decrease for all return periods shown under Scenario Cdry in all catchments. The maximum decrease in flows is 25 percent for the one-year return period in the Welcome catchment. In Flinders Island, Arthurs, Duck and Inglis-Flowerdale catchments, peak flows increase under scenarios Cwet and Cmid. The maximum increase in peak flows is 13 percent for the ten-year return period flow in the Flinders Island catchment. In some catchments, peak flows under Scenario Cmid are greater than those under Scenario Cwet. The selection of Cwet, Cmid and Cdry scenarios was based on mean annual runoff and peak flows may actually be higher in some years under Scenario Cmid relative to Scenario Cwet, or Scenario Cdry relative to Scenario Cmid because different global climate models (GCMs) were used to define these scenarios and these GCMs may scale peak rainfalls by different amounts.

40 ▪ River modelling for Tasmania. Volume 1: the Arthur-Inglis-Cam region © CSIRO 2009

Table 12. Peak flows for catchments under scenarios P and A, and under Scenario C relative to Scenario A

P A Cwet Cmid Cdry ML/d percent change relative to Scenario A 01_Flinders Island 2-year 6,532 6,531 6% 9% -6% 5-year 10,020 10,016 10% 9% -2% 10-year 12,949 12,941 13% 9% -3% 23_Arthur 2-year 44,424 44,421 2% 4% -4% 5-year 53,347 52,786 6% 6% -2% 10-year 65,109 65,106 0% 7% -4% 24_Welcome 2-year 1,076 1,074 -4% -14% -25% 5-year 1,448 1,447 2% -3% -17% 10-year 2,037 2,036 -6% -9% -20% 25_King Island 2-year 6,781 6,759 -7% -6% -18% 5-year 9,784 9,761 -1% -6% -15% 10-year 12,646 12,631 -7% -12% -21% 26_Montagu 2-year 2,175 2,168 -3% -4% -15% 5-year 3,013 3,005 0% 0% -11% 10-year 3,736 3,728 -3% 1% -13% 27_Duck 2-year 4,397 4,353 4% 3% -8% 5-year 5,742 5,695 2% 3% -8% 10-year 6,797 6,752 0% 3% -6% 28_Black-Detention 2-year 8,371 8,332 3% 2% -9% 5-year 10,148 10,108 1% 2% -8% 10-year 11,413 11,374 1% 3% -6% 29_Inglis-Flowerdale 2-year 7,576 7,525 2% 1% -10% 5-year 10,006 9,975 2% 5% -7% 10-year 12,029 11,999 6% 5% -1% 30_Cam 2-year 3,549 3,568 -1% -2% -13% 5-year 4,694 4,677 -2% 0% -10% 10-year 5,770 5,750 -1% 0% -9% 31_Emu 2-year 4,229 4,093 -1% -2% -9% 5-year 5,338 5,283 -3% -1% -11% 10-year 6,349 6,180 1% -6% -11% 32_Blythe 2-year 4,728 4,699 -2% -4% -11% 5-year 6,800 6,771 -3% -2% -11% 10-year 7,638 7,609 -2% -1% -11%

The percentage of time EOS flow is greater than 1 ML/day under scenarios P, A, and C is shown in Table 13. Flows less than 1 ML/day are defined as ‘cease-to-flow’ for the purposes of this report. The rivers in all catchments are essentially perennial, ceasing to flow for only a small percentage of time. The percentage of time that the river is flowing decreases by 2 percent or less under Scenario C relative to Scenario A in all catchments. A maximum reduction of 2 percent in the time the river is flowing is seen in Scenario P relative to Scenario A reflecting the low level of extractions in this region.

Table 13. Percentage of time end-of-system flow is greater than1 ML/day under scenarios P, A and C

P A Cwet Cmid Cdry 01_Flinders Island 95% 93% 94% 93% 93% 23_Arthur 100% 100% 100% 100% 100% 24_Welcome 100% 100% 99% 99% 99% 25_King Island 100% 99% 99% 98% 98% 26_Montagu 100% 100% 100% 100% 100% 27_Duck 100% 100% 100% 100% 100% 28_Black-Detention 100% 100% 100% 100% 100% 29_Inglis-Flowerdale 100% 99% 99% 99% 99% 30_Cam 100% 99% 99% 98% 98% 31_Emu 100% 96% 96% 94% 94% 32_Blythe 100% 100% 100% 100% 100%

The EOS flow during dry periods under Scenario A with relative changes under Scenario C is shown in Table 14. The EOS flow for the lowest one-, three- and five-year periods reduces significantly in all catchments under Scenario Cdry, with a maximum reduction of 26.3 percent in King Island catchment for the lowest one-year period. This indicates that under Scenario Cdry, the river system is more stressed in periods of low flow. The flow reduces for all reported periods under scenarios Cwet and Cmid relative to Scenario A in all catchments except Flinders Island which shows an increase in EOS flow for all reported periods under Scenario Cwet and the one- and five-year periods under Scenario Cmid.

42 ▪ River modelling for Tasmania. Volume 1: the Arthur-Inglis-Cam region © CSIRO 2009

Table 14. End-of-system flow for catchments during dry periods under Scenario A, and under Scenario C relative to Scenario A

A Cwet Cmid Cdry GL/y percent change relative to Scenario A 01_Flinders Island Lowest 1-year period of EOS flow 32.3 9.6% 2.4% -11.0% Lowest 3-year period of EOS flow 59.9 4.2% -0.1% -12.5% Lowest 5-year period of EOS flow 89.2 3.6% 0.8% -10.9% Mean annual EOS flow for 84 years 167.0 5.2% 2.4% -8.3% 23_Arthur Lowest 1-year period of EOS flow 1566.1 -3.1% -7.3% -11.6% Lowest 3-year period of EOS flow 2019.2 -2.2% -5.8% -10.9% Lowest 5-year period of EOS flow 2086.5 -1.6% -4.8% -9.8% Mean annual EOS flow for 84 years 2598.7 -1.7% -4.5% -9.3% 24_Welcome Lowest 1-year period of EOS flow 26.2 -10.2% -13.8% -26.2% Lowest 3-year period of EOS flow 41.2 -6.4% -12.4% -22.8% Lowest 5-year period of EOS flow 44.6 -7.3% -12.6% -22.7% Mean annual EOS flow for 84 years 76.3 -4.8% -11.8% -21.6% 25_King Island Lowest 1-year period of EOS flow 68.1 -9.8% -11.8% -26.3% Lowest 3-year period of EOS flow 118.0 -9.2% -12.7% -24.5% Lowest 5-year period of EOS flow 146.7 -10.3% -11.3% -23.1% Mean annual EOS flow for 84 years 231.0 -7.3% -10.7% -20.8% 26_Montagu Lowest 1-year period of EOS flow 55.7 -7.9% -11.3% -24.6% Lowest 3-year period of EOS flow 79.6 -4.9% -9.0% -19.7% Lowest 5-year period of EOS flow 86.5 -5.8% -8.6% -19.5% Mean annual EOS flow for 84 years 133.7 -2.8% -7.0% -16.4% 27_Duck Lowest 1-year period of EOS flow 87.6 -3.0% -4.7% -14.9% Lowest 3-year period of EOS flow 137.1 -3.8% -6.8% -18.5% Lowest 5-year period of EOS flow 166.3 -3.8% -5.9% -16.6% Mean annual EOS flow for 84 years 225.1 -1.7% -4.6% -14.0% 28_Black-Detention Lowest 1-year period of EOS flow 120.4 -7.3% -8.2% -17.7% Lowest 3-year period of EOS flow 189.7 -4.1% -5.0% -15.1% Lowest 5-year period of EOS flow 210.8 -4.4% -6.5% -15.9% Mean annual EOS flow for 84 years 308.0 -2.2% -4.9% -13.0% 29_Inglis-Flowerdale Lowest 1-year period of EOS flow 122.3 -7.7% -12.4% -21.8% Lowest 3-year period of EOS flow 246.1 -3.3% -5.7% -14.4% Lowest 5-year period of EOS flow 267.3 -4.1% -6.3% -14.3% Mean annual EOS flow for 84 years 349.5 -2.5% -5.3% -12.4% 30_Cam Lowest 1-year period of EOS flow 60.8 -9.0% -14.7% -23.5% Lowest 3-year period of EOS flow 106.7 -5.4% -9.8% -18.2% Lowest 5-year period of EOS flow 120.9 -5.5% -7.9% -16.3% Mean annual EOS flow for 84 years 163.9 -3.7% -6.9% -14.1% 31_Emu Lowest 1-year period of EOS flow 80.9 -9.5% -14.2% -22.7% Lowest 3-year period of EOS flow 120.4 -7.0% -11.4% -18.7% Lowest 5-year period of EOS flow 133.0 -4.8% -9.0% -14.3% Mean annual EOS flow for 84 years 182.5 -4.5% -7.6% -13.6% 32_Blythe Lowest 1-year period of EOS flow 120.6 -9.5% -12.0% -19.2% Lowest 3-year period of EOS flow 180.3 -6.7% -8.3% -14.6% Lowest 5-year period of EOS flow 190.5 -4.7% -8.0% -13.0% Mean annual EOS flow for 84 years 254.8 -4.4% -7.1% -12.7%

3.5 Share of available resource

The mean annual volume of extracted and non-extracted shares of water for Arthur-Inglis-Cam region under scenarios A and C are shown in Figure 13 and Table 15. The methods for modelling extractions and allocations are described in Section 2.1. There is a low volume of extracted water relative to the total mean annual volume of water in the catchment. The extracted water decreases by up to 1.2 GL/year under Scenario C relative to Scenario A. The non-extracted water decreases by 537 GL/year under Scenario Cdry relative to Scenario A. Total flow in the region decreases under Scenario C relative to Scenario A. The implication of these changes for environmental values is assessed in Graham et al. (2009).

. 5000

4000

3000

2000

1000

0 Mean annual volume (GL) ACwetCmidCdry

Non-extracted water Extracted water

Figure 13. Extracted and non-extracted shares of water for Arthur-Inglis-Cam region under scenarios A and C (annual)

Table 15. Extracted and non-extracted shares of water for Arthur-Inglis-Cam region under scenarios A and C (annual)

A Cwet Cmid Cdry GL/y Non-extracted water 4696 4592 4452 4159 Extracted water 93 92 91 91 Total 4789 4684 4543 4250

The mean annual extracted and non-extracted shares of water for each catchment are shown in Figure 14 and Table 16. The volume of extracted water does not change significantly under Scenario C relative to Scenario A for any catchment. The total streamflow decreases under Scenario C relative to Scenario A in all catchments except Flinders Island where total streamflow increases under scenarios Cwet and Cmid relative to Scenario A. This implies that the reduction in the runoff under Scenario C would be borne more in the non-extracted proportion of river flows due to the extraction rules, which may have implications for the environmental values in the river systems.

(a) 01_Flinders Island (b) 23_Arthur

200 3000 . 180 . 160 2500 140 2000 120 100 1500 80 60 1000 40 500 20

Mean annual volume (GL) 0 Mean annual volume (GL) 0 ACwetCmidCdry ACwetCmidCdry Non-extracted water Extracted water Non-extracted water Extracted water

80 250 . . 70 200 60 50 150 40 30 100 20 50 10

Mean annual volume (GL) 0 Mean annual volume (GL) 0 ACwetCmidCdry ACwetCmidCdry Non-extracted water Extracted water Non-extracted water Extracted water

(e) 26_Montagu (f) 27_Duck

140 250 . . 120 200 100 80 150

60 100 40 50 20

Mean annual volume (GL) 0 Mean annual volume (GL) 0 ACwetCmidCdry ACwetCmidCdry Non-extracted water Extracted water Non-extracted water Extracted water

(g) 28_Black-Detention (h) 29_Inglis-Flowerdale

350 400 . . 300 350 250 300 250 200 200 150 150 100 100 50 50

Mean annual volume (GL) 0 Mean annual volume (GL) 0 ACwetCmidCdry ACwetCmidCdry Non-extracted water Extracted water Non-extracted water Extracted water

Figure 14. Extracted and non-extracted shares of water for catchments under scenarios A and C (annual)

(i) 30_Cam (j) 31_Emu

180 250 . . 160 140 200 120 150 100 80 100 60 40 50 20

Mean annual volume (GL) 0 Mean annual volume (GL) 0 ACwetCmidCdry ACwetCmidCdry Non-extracted water Extracted water Non-extracted water Extracted water

(k) 32_Blythe

300 . 250

200

150

100

Mean annual volume (GL) 0 ACwetCmidCdry Non-extracted water Extracted water

Figure 14. Extracted and non-extracted shares of water for catchments under scenarios A and C (annual) (continued)

Table 16. Extracted and non-extracted shares of water for catchments under scenarios A and C (annual)

A Cwet Cmid Cdry GL/y 01_Flinders Island Non-extracted water 167.0 175.7 171.0 153.1 Extracted water 1.9 1.9 1.9 1.9 Total 169.0 177.6 172.9 155.0 23_Arthur Non-extracted water 2607.3 2563.5 2489.3 2365.2 Extracted water 4.9 4.9 4.9 4.9 Total 2612.2 2568.3 2494.2 2370.1 24_Welcome Non-extracted water 76.3 72.7 67.3 59.9 Extracted water 0.4 0.4 0.4 0.4 Total 76.7 73.0 67.6 60.2 25_King Island Non-extracted water 231.0 214.2 206.3 183.0 Extracted water 3.8 3.8 3.8 3.7 Total 234.8 218.0 210.0 186.8 26_Montagu Non-extracted water 133.7 129.8 124.3 111.7 Extracted water 1.9 1.9 1.8 1.8 Total 135.5 131.7 126.1 113.6 27_Duck Non-extracted water 226.7 222.8 216.4 195.2 Extracted water 12.8 12.8 12.6 12.5 Total 239.5 235.5 229.0 207.7 28_Black-Detention Non-extracted water 308.0 301.3 292.8 268.1 Extracted water 11.2 11.1 10.9 10.9 Total 319.2 312.4 303.7 279.0 29_Inglis-Flowerdale Non-extracted water 349.5 340.7 330.9 306.1 Extracted water 13.1 13.1 12.9 13.0 Total 362.6 353.7 343.8 319.1 30_Cam Non-extracted water 166.3 160.2 155.0 143.2 Extracted water 4.2 4.2 4.1 4.1 Total 170.5 164.4 159.2 147.3 31_Emu Non-extracted water 175.7 167.6 162.0 151.0 Extracted water 31.5 31.5 31.2 31.3 Total 207.2 199.1 193.3 182.3 32_Blythe Non-extracted water 254.8 243.7 236.6 222.4 Extracted water 6.9 6.9 6.9 6.9 Total 261.7 250.6 243.5 229.3

The mean extracted and non-extracted shares of water for Arthur-Inglis-Cam region for summer only are shown in Table 17. The total streamflow in summer is less under Scenario Cmid compared to Scenario Cdry. The mean summer extraction does not change significantly under Scenario C compared to Scenario A. The extracted volume of water is small in summer compared with the total streamflow available.

Table 17. Extracted and non-extracted shares of water for Arthur-Inglis-Cam region under scenarios A and C (summer – October to March inclusive)

A Cwet Cmid Cdry GL/season Non-extracted water 1133 1108 991 1008 Extracted water 43 43 42 43 Total 1176 1151 1033 1050

The mean extracted and non-extracted shares of water for each catchment for summer only are shown in Table 18. The total streamflow in summer is lower under Scenario Cmid relative to Cdry. The mean summer extraction does not change significantly under Scenario C relative to Scenario A. The extracted proportion of water in summer is significant in the Emu catchment. In all catchments, the extracted proportion of water over summer is larger than the annual extraction.

Table 18. Extracted and non-extracted shares of water for catchments under scenarios A and C (summer – October to March inclusive)

A Cwet Cmid Cdry GL/season 01_Flinders Island Non-extracted water 45.1 50.9 45.6 45.5 Extracted water 0.2 0.2 0.2 0.2 Total 45.4 51.1 45.8 45.7 23_Arthur Non-extracted water 630.1 616.3 551.9 572.4 Extracted water 3.7 3.7 3.7 3.7 Total 633.9 620.1 555.6 576.1 24_Welcome Non-extracted water 21.3 20.5 17.6 17.0 Extracted water 0.1 0.1 0.1 0.1 Total 21.4 20.6 17.7 17.1 25_King Island Non-extracted water 54.3 50.8 45.0 43.0 Extracted water 0.4 0.4 0.4 0.4 Total 54.7 51.2 45.4 43.4 26_Montagu Non-extracted water 32.5 31.3 27.6 27.0 Extracted water 0.6 0.6 0.6 0.6 Total 33.1 31.9 28.2 27.6 27_Duck Non-extracted water 53.0 50.9 46.3 44.1 Extracted water 6.0 5.9 5.8 5.8 Total 59.0 56.9 52.1 49.9 28_Black-Detention Non-extracted water 65.7 63.6 56.7 56.5 Extracted water 4.9 4.8 4.7 4.7 Total 70.6 68.4 61.4 61.3 29_Inglis-Flowerdale Non-extracted water 86.2 83.7 75.5 75.3 Extracted water 6.8 6.8 6.7 6.8 Total 93.1 90.6 82.2 82.1 30_Cam Non-extracted water 40.2 39.0 34.7 34.8 Extracted water 2.2 2.2 2.2 2.2 Total 42.4 41.2 36.9 37.0 31_Emu Non-extracted water 36.4 35.0 30.1 31.2 Extracted water 15.7 15.7 15.6 15.7 Total 52.2 50.8 45.7 46.9 32_Blythe Non-extracted water 68.4 66.0 59.9 61.0 Extracted water 2.4 2.4 2.4 2.4 Total 70.8 68.3 62.2 63.3

The mean percentage of water extracted as a proportion of total EOS flow under scenarios A and C annually and for summer and winter are shown in Table 19, Table 20 and Table 21 respectively. On an annual basis, the percentage of water extracted as a proportion of total flow is 6 percent or less in the majority of catchments. The exception to this is the Emu catchment where an annual mean of 15 percent of water is extracted under Scenario A, reflecting water use in the catchment for town water supply and industry. The proportion of the total flow extracted in summer is larger than the annual proportion of flow extracted in the majority of catchments, with the largest proportional summer extractions in the Duck, Black-Detention, Inglis-Flowerdale, Cam and Emu catchments. Mean summer extractions are 30 percent of total flows under Scenario A in the Emu catchment, increasing to 33 percent under Scenario Cdry. The extraction as a

proportion of total flow is the same or less in winter relative to summer for all catchments other than under Scenario Cdry in Flinders Island. All catchments show little or no change in the percentage of extractions as a proportion of total flow under Scenario C compared to Scenario A.

Table 19. Percentage of water extracted as a proportion of total end-of-system flow for catchments under scenarios A and C (annual)

A Cwet Cmid Cdry 01_Flinders Island 1% 1% 1% 1% 23_Arthur 0% 0% 0% 0% 24_Welcome 0% 0% 1% 1% 25_King Island 2% 2% 2% 2% 26_Montagu 1% 1% 1% 2% 27_Duck 5% 5% 5% 6% 28_Black-Detention 4% 4% 4% 4% 29_Inglis-Flowerdale 4% 4% 4% 4% 30_Cam 2% 3% 3% 3% 31_Emu 15% 16% 16% 17% 32_Blythe 3% 3% 3% 3% Region mean 2% 2% 2% 2%

Table 20. Percentage of water extracted as a proportion of total end-of-system flow for catchments under scenarios A and C (summer – October to March inclusive)

A Cwet Cmid Cdry 01_Flinders Island 1% 0% 1% 1% 23_Arthur 1% 1% 1% 1% 24_Welcome 1% 1% 1% 1% 25_King Island 1% 1% 1% 1% 26_Montagu 2% 2% 2% 2% 27_Duck 10% 10% 11% 12% 28_Black-Detention 7% 7% 8% 8% 29_Inglis-Flowerdale 7% 8% 8% 8% 30_Cam 5% 5% 6% 6% 31_Emu 30% 31% 34% 33% 32_Blythe 3% 3% 4% 4% Region mean 4% 4% 4% 4%

Table 21. Percentage of water extracted as a proportion of total end-of-system flow for catchments under scenarios A and C (winter – April to September inclusive)

A Cwet Cmid Cdry 01_Flinders Island 1% 1% 1% 2% 23_Arthur 0% 0% 0% 0% 24_Welcome 0% 0% 0% 1% 25_King Island 2% 2% 2% 2% 26_Montagu 1% 1% 1% 1% 27_Duck 4% 4% 4% 4% 28_Black-Detention 3% 3% 3% 3% 29_Inglis-Flowerdale 2% 2% 2% 3% 30_Cam 2% 2% 2% 2% 31_Emu 10% 11% 11% 12% 32_Blythe 2% 2% 2% 3% Region mean 1% 1% 1% 2%

4 Under historical climate (Scenario A) and recent climate (Scenario B)

This section compares recent hydrology (under Scenario B) with historical hydrology (under Scenario A). The mean end-of-system (EOS) flow volume in GL/year, and daily EOS flow duration plots for each catchment are shown in Figure 15 for each catchment. The mean monthly flow for recent climate is generally less than the long-term mean in all catchments in all months with the exception of September and October where flows are higher in some catchments under Scenario B relative to Scenario A. Mean flows in September and October under recent climate are greater than the long-term mean in the Black-Detention, Cam, Emu and Blythe catchments. Mean flows in January under recent climate are higher than the long-term mean in Flinders Island catchment. The flow duration curves show that flows under recent climate have generally been lower than the long-term mean over the full range of flows.

(a-1) 01_Flinders Island – monthly flow (a-2) 01_Flinders Island – daily flow duration

1.0 100000 . B B 0.8 . 10000 A A 0.6 1000

0.4 100

0.2 10 EOS dailyflow (ML) EOS monthly flow (GL) 0.0 1 JFMAMJJASOND 0 20406080100 Month Percent time volume is exceeded

(b-1) 23_Arthur – monthly flow (b-2) 23_Arthur – daily flow duration

16 100000 . 14 B B . 10000 12 A A 10 1000 8 6 100

4 10

2 EOS dailyflow (ML) EOS monthly flow (GL) 0 1 JFMAMJ JASOND 0 20406080100 Month Percent time volume is exceeded

(c-1) 24_Welcome – monthly flow (c-2) 24_Welcome – daily flow duration

0.6 100000 . B B 0.5 . 10000 A A 0.4 1000 0.3 100 0.2 10 0.1 EOS dailyflow (ML) EOS monthly flow (GL) 0.0 1 JFMAMJ JASOND 0 20406080100 Month Percent time volume is exceeded

Figure 15. Mean end-of-system monthly flow and daily flow duration curves for catchments under scenarios A and B

(d-1) 25_King Island – monthly flow (d-2) 25_King Island – daily flow duration

1.8 100000 . 1.6 B B . 10000 1.4 A A 1.2 1000 1.0 0.8 100 0.6 0.4 10 EOS dailyflow (ML)

EOS monthly flow (GL) 0.2 0.0 1 JFMAMJ JASOND 0 20406080100 Month Percent time volume is exceeded

(e-1) 26_Montagu – monthly flow (e-2) 26_Montagu – daily flow duration

1.0 100000 . B B 0.8 . 10000 A A 0.6 1000

0.4 100

0.2 10 EOS dailyflow (ML) EOS monthly flow (GL) 0.0 1 JFMAMJ JASOND 0 20406080100 Month Percent time volume is exceeded

(f-1) 27_Duck – monthly flow (f-2) 27_Duck – daily flow duration

1.6 100000 . 1.4 B B . 10000 1.2 A A 1.0 1000 0.8 0.6 100

0.4 10

0.2 EOS dailyflow (ML) EOS monthly flow (GL) 0.0 1 JFMAMJ JASOND 0 20406080100 Month Percent time volume is exceeded

(g-1) 28_Black-Detention – monthly flow (g-2) 28_Black-Detention – daily flow duration

2.5 100000 . B B 2.0 . 10000 A A 1.5 1000

1.0 100

0.5 10 EOS dailyflow (ML) EOS monthly flow (GL) 0.0 1 JFMAMJ JASOND 0 20406080100 Month Percent time volume is exceeded

Figure 15. Mean end-of-system monthly flow and daily flow duration curves for catchments under scenarios A and B (continued)

(h-1) 29_Inglis-Flowerdale – monthly flow (h-2) 29_Inglis-Flowerdale – daily flow duration

2.5 100000 . B B 2.0 . 10000 A A 1.5 1000

1.0 100

0.5 10 EOS dailyflow (ML) EOS monthly flow (GL) 0.0 1 JFMAMJ JASOND 0 20406080100 Month Percent time volume is exceeded

(i-1) 30_Cam – monthly flow (i-2) 30_Cam – daily flow duration

1.2 100000 . B B 1.0 . 10000 A A 0.8 1000 0.6 100 0.4 10 0.2 EOS dailyflow (ML) EOS monthly flow (GL) 0.0 1 JFMAMJ JASOND 0 20406080100 Month Percent time volume is exceeded

(j-1) 31_Emu – monthly flow (j-2) 31_Emu – daily flow duration

1.4 100000 . B B

1.2 . 10000 A 1.0 A 0.8 1000

0.6 100 0.4 10 0.2 EOS dailyflow (ML) EOS monthly flow (GL) 0.0 1 JFMAMJ JASOND 0 20406080100 Month Percent time volume is exceeded

(k-1) 32_Blythe – monthly flow (k-2) 32_Blythe – daily flow duration

1.6 100000 . 1.4 B B . 10000 1.2 A A 1.0 1000 0.8 0.6 100

0.4 10

0.2 EOS dailyflow (ML) EOS monthly flow (GL) 0.0 1 JFMAMJ JASOND 0 20406080100 Month Percent time volume is exceeded

Figure 15. Mean end-of-system monthly flow and daily flow duration curves for catchments under scenarios A and B (continued)

The extracted and non-extracted shares of water for Arthur-Inglis-Cam are shown in Figure 16 and Table 22 under scenarios A and B. It can be seen that the total streamflow in the region is lower under Scenario B; however, the volume of extracted water reduces by a mean of only 2 GL/year annually, reflecting the low level of extraction across the region. The reduction in the total EOS flow under Scenario B relative to Scenario A is borne by the non-extracted water. The implication of these changes for environmental values is assessed in Graham et al. (2009).

5000 . 4500 4000 3500 3000 2500 2000 1500 1000 500

Mean annualMean volume(GL) 0 AB Non-extracted water Extracted water

Figure 16. Mean annual extracted and non-extracted shares of water for Arthur-Inglis-Cam region under scenarios A and B

Table 22. Mean annual extracted and non-extracted shares of water for Arthur-Inglis-Cam region under scenarios A and B

A B GL/y Non-extracted water 4696 4040 Extracted water 93 91 Total 4789 4131

The extracted and non-extracted shares of water under scenarios A and B for summer only are shown in Table 23. There is a decrease of 658 GL/season in mean summer flows under Scenario B relative to Scenario A. This has only a minimal impact on the mean summer extraction volume, reflecting the low level of water usage in the region.

Table 23. Extracted and non-extracted shares of water for Arthur-Inglis-Cam region under scenarios A and B (summer – October to March inclusive)

A B GL/season Non-extracted water 1133 962 Extracted water 43 42 Total 1176 1004

The mean annual extracted and non-extracted shares of water for each catchment are shown in Table 24 for each catchment under scenarios A and B. The mean annual volume of total water is less under Scenario B relative to Scenario A in all catchments. The volume of water extracted under Scenario B is the same or only slightly less than Scenario A in all catchments. The total flow has greatly reduced under recent climate relative to the long-term mean, with a reduction of 29 percent in the Welcome and King catchments. This may have implications for the environment such as effects on connectivity of a river and its bordering ecosystem.

Table 24. Mean annual extracted and non-extracted shares of water for catchments under scenarios A and B.

A B GL/y 01_Flinders Island Non-extracted water 167.0 124.8 Extracted water 1.9 1.9 Total 169.0 126.7 23_Arthur Non-extracted water 2607.3 2338.9 Extracted water 4.9 4.9 Total 2612.2 2343.7 24_Welcome Non-extracted water 76.3 54.8 Extracted water 0.4 0.4 Total 76.7 55.2 25_King Island Non-extracted water 231.0 164.9 Extracted water 3.8 3.7 Total 234.8 168.6 26_Montagu Non-extracted water 133.7 110.4 Extracted water 1.9 1.9 Total 135.5 112.2 27_Duck Non-extracted water 226.7 184.7 Extracted water 12.8 12.4 Total 239.5 197.1 28_Black-Detention Non-extracted water 308.0 253.2 Extracted water 11.2 10.7 Total 319.2 263.9 29_Inglis-Flowerdale Non-extracted water 349.5 284.6 Extracted water 13.1 12.7 Total 362.6 297.4 30_Cam Non-extracted water 166.3 146.3 Extracted water 4.2 4.0 Total 170.5 150.3 31_Emu Non-extracted water 175.7 156.7 Extracted water 31.5 31.3 Total 207.2 188.0 32_Blythe Non-extracted water 254.8 220.7 Extracted water 6.9 6.9 Total 261.7 227.5

The mean annual extracted and non-extracted shares of water for each catchment for summer only under scenarios A and B are shown in Table 25. The mean level of extraction is less than 12 percent in all catchments over summer, except for in the Emu catchment where the level of extraction is high. The mean summer volume of water extracted does not vary significantly under Scenario B relative to Scenario A.

Table 25. Extracted and non-extracted shares of water for catchments under scenarios A and B (summer – October to April inclusive)

A B GL/season 01_Flinders Island Non-extracted water 45.1 37.2 Extracted water 0.2 0.2 Total 45.4 37.4 23_Arthur Non-extracted water 630.1 539.8 Extracted water 3.7 3.7 Total 633.9 543.6 24_Welcome Non-extracted water 21.3 16.1 Extracted water 0.1 0.1 Total 21.4 16.2 25_King Island Non-extracted water 54.3 37.9 Extracted water 0.4 0.4 Total 54.7 38.3 26_Montagu Non-extracted water 32.5 27.9 Extracted water 0.6 0.6 Total 33.1 28.5 27_Duck Non-extracted water 53.0 42.4 Extracted water 6.0 5.7 Total 59.0 48.1 28_Black-Detention Non-extracted water 65.7 56.4 Extracted water 4.9 4.5 Total 70.6 60.9 29_Inglis-Flowerdale Non-extracted water 86.2 73.3 Extracted water 6.8 6.6 Total 93.1 79.9 30_Cam Non-extracted water 40.2 36.2 Extracted water 2.2 2.2 Total 42.4 38.4 31_Emu Non-extracted water 36.4 32.4 Extracted water 15.7 15.7 Total 52.2 48.1 32_Blythe Non-extracted water 68.4 62.0 Extracted water 2.4 2.4 Total 70.8 64.4

5 Under future development (Scenario D)

The impacts of future development under future climate are modelled in Scenario D. The impacts of future development are shown relative to Scenario C, which models future climate with current infrastructure.

5.1 Hydrological impacts of future development

The projected changes in mean annual inflows to each catchment where there is an increase in future forestry development are shown in Table 26 under Scenario D as a percent difference from Scenario C. Scenario C represents future climate and Scenario D represents future development under future climate. There is a small change in inflows of 1 percent or less for the Black-Detention, Cam and Emu catchments under Scenario D relative to Scenario C. The change in inflows under Scenario D relative to Scenario C is greater in the Inglis-Flowerdale catchment with a reduction of 1.8 percent, and the Blythe catchment with a reduction of 3.6 to 3.7 percent. This reflects the fact that the largest increases in future forestry were concentrated in these catchments (Viney et al., 2009), as shown in Figure 5.

Table 26. Comparison of inflows from catchment runoff under Scenario D relative to Scenario C

Dwet Dmid Ddry percent change percent change percent change relative to Cwet relative to Cmid relative to Cdry 01_Flinders Island 0.0% 0.0% 0.0% 23_Arthur 0.0% 0.0% 0.0% 24_Welcome 0.0% 0.0% 0.0% 25_King Island 0.0% 0.0% 0.0% 26_Montagu 0.0% 0.0% 0.0% 27_Duck 0.0% 0.0% 0.0% 28_Black-Detention -0.3% -0.3% -0.3% 29_Inglis-Flowerdale -1.8% -1.8% -1.9% 30_Cam -0.7% -0.7% -0.7% 31_Emu -1.0% -1.0% -1.0% 32_Blythe -3.6% -3.7% -3.7% Region mean -0.4% -0.4% -0.4%

The projected changes in end-of-system (EOS) flows are shown in Table 27 as change in percentage of time end-of-system flows are greater than 1 ML. There are only very minor changes in the Inglis-Flowerdale, Cam and Emu catchments. There is no change in percentage cease-to-flow time under Scenario D relative to Scenario C in the Blythe catchment where the largest reduction in inflows was observed, as the river is essentially perennial.

Table 27. Percent time end-of-system flow for catchments is greater than 1 ML/day under Scenario D relative to Scenario C

Cwet Cmid Cdry Dwet Dmid Ddry percentage of time EOS flow >1 ML/d 28_Black-Detention 100% 100% 100% 100% 100% 100% 29_Inglis-Flowerdale 99% 99% 99% 98% 97% 98% 30_Cam 99% 98% 98% 99% 98% 98% 31_Emu 96% 94% 95% 94% 92% 93% 32_Blythe 100% 100% 100% 100% 100% 100%

The small projected change in total flow and runoff under Scenario D relative to Scenario C is predicted to translate to a reduction in extraction volumes. The mean total extractions in the Blythe and Inglis-Flowerdale catchments are reduced by 3.5 and 6.9 percent respectively under Scenario Cdry relative to Scenario A. This indicates that the impact of future development on the ability to extract water is greater than the impact of future development on catchment runoff or EOS flows.

Table 28. Comparison of extractions for catchments under Scenario D relative to Scenario C

Cwet Cmid Cdry Dwet Dmid Ddry GL/y percent change percent change percent change relative Cwet relative to Cmid relative to Cdry 01_Flinders Island Surety 1 0.0 0.0 0.0 0.0% 0.0% 0.0% Surety 2 0.0 0.0 0.0 - - - Surety 3 0.0 0.0 0.0 - - - Surety 4 0.0 0.0 0.0 - - - Surety 5 0.5 0.5 0.5 0.0% 0.0% 0.0% Surety 6 0.3 0.3 0.3 0.0% 0.0% 0.0% Surety 7 0.0 0.0 0.0 - - - Surety 8 0.0 0.0 0.0 - - - Unlicensed 1.1 1.1 1.1 0.0% 0.0% 0.0% Total extractions 1.9 1.9 1.9 0.0% 0.0% 0.0% 23_Arthur Surety 1 0.1 0.1 0.1 0.0% 0.0% 0.0% Surety 2 0.0 0.0 0.0 - - - Surety 3 0.0 0.0 0.0 - - - Surety 4 0.0 0.0 0.0 - - - Surety 5 1.3 1.3 1.3 0.0% 0.0% 0.0% Surety 6 0.0 0.0 0.0 - - - Surety 7 0.0 0.0 0.0 - - - Surety 8 0.0 0.0 0.0 - - - Unlicensed 3.5 3.5 3.5 0.0% 0.0% 0.0% Total extractions 4.9 4.9 4.9 0.0% 0.0% 0.0% 24_Welcome Surety 1 0.0 0.0 0.0 - - - Surety 2 0.0 0.0 0.0 - - - Surety 3 0.0 0.0 0.0 - - - Surety 4 0.0 0.0 0.0 - - - Surety 5 0.3 0.3 0.3 0.0% 0.0% 0.0% Surety 6 0.0 0.0 0.0 - - - Surety 7 0.0 0.0 0.0 - - - Surety 8 0.0 0.0 0.0 - - - Unlicensed 0.0 0.0 0.0 0.0% 0.0% 0.0% Total extractions 0.4 0.4 0.4 0.0% 0.0% 0.0% 25_King Island Surety 1 0.2 0.2 0.2 0.0% 0.0% 0.0% Surety 2 0.0 0.0 0.0 - - - Surety 3 0.0 0.0 0.0 - - - Surety 4 0.0 0.0 0.0 - - - Surety 5 0.8 0.8 0.8 0.0% 0.0% 0.0% Surety 6 0.0 0.0 0.0 - - - Surety 7 0.0 0.0 0.0 - - - Surety 8 0.0 0.0 0.0 - - - Unlicensed 2.8 2.7 2.7 0.0% 0.0% 0.0% Total extractions 3.8 3.8 3.7 0.0% 0.0% 0.0%

Table 28. Comparison of extractions for catchments under Scenario D relative to Scenario C (continued)

Cwet Cmid Cdry Dwet Dmid Ddry GL/y percent change percent change percent change relative Cwet relative to Cmid relative to Cdry 26_Montagu Surety 1 0.2 0.2 0.2 0.0% 0.0% 0.0% Surety 2 0.0 0.0 0.0 - - - Surety 3 0.0 0.0 0.0 - - - Surety 4 0.0 0.0 0.0 - - - Surety 5 1.4 1.4 1.4 0.0% 0.0% 0.0% Surety 6 0.0 0.0 0.0 - - - Surety 7 0.0 0.0 0.0 - - - Surety 8 0.0 0.0 0.0 - - - Unlicensed 0.3 0.3 0.3 0.0% 0.0% 0.0% Total extractions 1.9 1.8 1.8 0.0% 0.0% 0.0% 27_Duck Surety 1 0.8 0.8 0.8 0.0% 0.0% 0.0% Surety 2 0.0 0.0 0.0 - - - Surety 3 0.0 0.0 0.0 - - - Surety 4 0.0 0.0 0.0 - - - Surety 5 9.5 9.4 9.3 0.0% 0.0% 0.0% Surety 6 0.2 0.2 0.2 0.0% 0.0% 0.0% Surety 7 0.0 0.0 0.0 - - - Surety 8 0.0 0.0 0.0 - - - Unlicensed 2.3 2.2 2.2 0.0% 0.0% 0.0% Total extractions 12.8 12.6 12.5 0.0% 0.0% 0.0% 28_Black-Detention Surety 1 0.2 0.2 0.2 -0.2% -0.7% -0.3% Surety 2 0.0 0.0 0.0 - - - Surety 3 0.0 0.0 0.0 - - - Surety 4 0.0 0.0 0.0 - - - Surety 5 7.9 7.8 7.8 -0.8% -0.8% -0.9% Surety 6 0.3 0.3 0.3 -0.4% -0.3% -0.5% Surety 7 0.0 0.0 0.0 - - - Surety 8 0.0 0.0 0.0 - - - Unlicensed 2.7 2.5 2.6 -2.3% -2.1% -2.2% Total extractions 11.1 10.9 10.9 -1.1% -1.1% -1.1% 29_Inglis-Flowerdale Surety 1 0.5 0.5 0.5 -4.4% -4.2% -4.5% Surety 2 0.0 0.0 0.0 - - - Surety 3 0.0 0.0 0.0 - - - Surety 4 0.0 0.0 0.0 - - - Surety 5 6.3 6.3 6.3 -3.6% -3.5% -3.7% Surety 6 5.3 5.2 5.3 -2.7% -3.0% -2.8% Surety 7 0.0 0.0 0.0 - - - Surety 8 0.0 0.0 0.0 - - - Unlicensed 1.0 1.0 1.0 -5.2% -4.8% -5.2% Total extractions 13.1 12.9 13.0 -3.4% -3.4% -3.5%

Table 28. Comparison of extractions for catchments under Scenario D relative to Scenario C (continued)

Cwet Cmid Cdry Dwet Dmid Ddry GL/y percent change percent change percent change relative Cwet relative to Cmid relative to Cdry 30_Cam Surety 1 1.4 1.4 1.4 -0.4% -0.4% -0.3% Surety 2 0.0 0.0 0.0 - - - Surety 3 0.0 0.0 0.0 - - - Surety 4 0.0 0.0 0.0 - - - Surety 5 1.9 1.9 1.9 -1.6% -1.7% -1.8% Surety 6 0.0 0.0 0.0 -0.6% 0.0% 0.0% Surety 7 0.0 0.0 0.0 - - - Surety 8 0.0 0.0 0.0 - - - Unlicensed 0.9 0.9 0.9 -1.9% -1.8% -2.0% Total extractions 4.2 4.1 4.1 -1.3% -1.3% -1.4% 31_Emu Surety 1 0.1 0.1 0.1 0.0% 0.0% 0.0% Surety 2 0.0 0.0 0.0 - - - Surety 3 0.0 0.0 0.0 - - - Surety 4 0.0 0.0 0.0 - - - Surety 5 30.4 30.1 30.3 -0.4% -0.5% -0.4% Surety 6 0.1 0.1 0.1 -5.3% -5.4% -6.4% Surety 7 0.0 0.0 0.0 - - - Surety 8 0.0 0.0 0.0 - - - Unlicensed 0.9 0.9 0.9 -1.0% -1.2% -1.1% Total extractions 31.5 31.2 31.3 -0.4% -0.5% -0.5% 32_Blythe Surety 1 0.2 0.2 0.2 -7.5% -7.6% -7.6% Surety 2 0.0 0.0 0.0 - - - Surety 3 0.0 0.0 0.0 - - - Surety 4 0.0 0.0 0.0 - - - Surety 5 6.1 6.1 6.1 -6.7% -6.6% -7.0% Surety 6 0.2 0.2 0.2 -4.6% -4.1% -4.5% Surety 7 0.0 0.0 0.0 - - - Surety 8 0.0 0.0 0.0 - - - Unlicensed 0.4 0.4 0.4 -4.2% -4.2% -4.9% Total extractions 6.9 6.9 6.9 -6.5% -6.4% -6.9% Total Surety 1 3.6 3.6 3.6 -1.1% -1.1% -1.1% Surety 2 0.0 0.0 0.0 - - - Surety 3 0.0 0.0 0.0 - - - Surety 4 0.0 0.0 0.0 - - - Surety 5 66.4 65.9 65.9 -1.3% -1.3% -1.3% Surety 6 6.4 6.3 6.3 -2.4% -2.6% -2.6% Surety 7 0.0 0.0 0.0 - - - Surety 8 0.0 0.0 0.0 - - - Unlicensed 15.9 15.6 15.6 -1.0% -0.9% -1.0% Total extractions 92.3 91.4 91.5 -1.3% -1.3% -1.4%

The mean monthly percent change in EOS flow under Scenario D relative to Scenario C is shown in Figure 17. The largest percentage change is observed in the drier summer months. The maximum percentage change in mean monthly EOS volume is 0.14 percent in the Blythe catchment.

(a-1) 28_Black-Detention – monthly flows (scenarios P, (a-2) 28_Black-Detention – monthly flows (Scenario D) A and C) 2.5 2 . S

C range . 0 2.0

Cmid . -2 A -4 1.5 P -6 -8 1.0 -10

0.5 to Scenario C -12 D range monthlyflow relative

Percent change in EO -14

EOS monthly flow (GL) Dmid 0.0 -16 JFMAMJJASOND JFMAMJ JASOND Month Month

(b-1) 29_Inglis-Flowerdale – monthly flows (scenarios P, (b-2) 29_Inglis-Flowerdale – monthly flows (Scenario D) A and C) 2.5 2 . S

C range . 0 2.0

Cmid . -2 A -4 1.5 P -6 -8 1.0 -10

0.5 to Scenario C -12 D range monthlyflow relative

Percent change in EO -14

EOS monthly flow (GL) Dmid 0.0 -16 JFMAMJJASOND JFMAMJ JASOND Month Month

(c-1) 30_Cam – monthly flows (scenarios P, (c-2) 30_Cam – monthly flows (Scenario D) A and C) 1.2 2 . S

C range . 0 1.0

Cmid . -2 0.8 A -4 P -6 0.6 -8 0.4 -10

to Scenario C -12 D range 0.2 monthly flow relative

Percent change in EO -14

EOS monthly flow (GL) Dmid 0.0 -16 JFMAMJJASOND JFMAMJ JASOND Month Month

(d-1) 31_Emu – monthly flows (scenarios P, (d-2) 31_Emu – monthly flows (Scenario D) A and C) 1.4 2 . S 1.2 C range . 0

Cmid . -2 1.0 A -4 0.8 P -6 0.6 -8 -10 0.4 to Scenario C -12 D range

0.2 monthly flow relative

Percent change in EO -14

EOS monthly flow (GL) Dmid 0.0 -16 JFMAMJJASOND JFMAMJ JASOND Month Month

Figure 17. Mean monthly end-of-system flow under scenarios P, A and C; and changes under Scenario D relative to Scenario C

(e-1) 32_Blythe – monthly flows (scenarios P, (e-2) 32_Blythe – monthly flows (Scenario D) A and C) 1.8 2 . S

1.6 C range . 0

1.4 Cmid . -2 1.2 A -4 1.0 P -6 0.8 -8 0.6 -10

0.4 to Scenario C -12 D range monthlyflow relative

0.2 Percent change in EO -14

EOS monthly flow (GL) Dmid 0.0 -16 JFMAMJJASOND JFMAMJ JASOND Month Month

Figure 17. Mean monthly end-of-system flow under scenarios P, A and C; and changes under Scenario D relative to Scenario C (continued)

Peak flows under Scenario C and relative changes under Scenario D are shown in Table 29. Peak flows are reduced for all return periods in all catchments under Scenario D relative to Scenario C, showing that high flows are impacted by future development. These impacts are outcomes of the FCFC modelling used to determine the effects of forestry on streamflow (Viney et al., 2009) and impoundments for the irrigation developments.

Table 29. Comparison of change in peak flows for catchments under Scenario D relative to Scenario C

Cwet Cmid Cdry Dwet Dmid Ddry ML/d percent change percent change percent change relative to Cwet relative to Cmid relative to Cdry 01_Flinders Island 2-year 6,953 7,123 6,168 0.00% 0.00% 0.00% 5-year 11,031 10,926 9,779 0.00% 0.00% 0.00% 10-year 14,602 14,129 12,531 0.00% 0.00% 0.00% 23_Arthur 2-year 45,219 46,266 42,583 0.00% 0.00% 0.00% 5-year 56,197 56,005 51,870 0.00% 0.00% 0.00% 10-year 64,914 69,496 62,603 0.00% 0.00% 0.00% 24_Welcome 2-year 1,031 924 808 0.00% 0.00% 0.00% 5-year 1,475 1,397 1,200 0.00% 0.00% 0.00% 10-year 1,918 1,846 1,624 0.00% 0.00% 0.00% 25_King Island 2-year 6,313 6,332 5,533 0.00% 0.00% 0.00% 5-year 9,656 9,165 8,288 0.00% 0.00% 0.00% 10-year 11,807 11,076 10,021 0.00% 0.00% 0.00% 26_Montagu 2-year 2,101 2,072 1,839 0.00% 0.00% 0.00% 5-year 2,996 3,001 2,684 0.00% 0.00% 0.00% 10-year 3,632 3,754 3,231 0.00% 0.00% 0.00% 27_Duck 2-year 4,548 4,493 4,014 0.00% 0.00% 0.00% 5-year 5,796 5,876 5,248 0.00% 0.00% 0.00% 10-year 6,780 6,954 6,332 0.00% 0.00% 0.00% 28_Black-Detention 2-year 8,557 8,460 7,574 -0.15% -0.24% -0.18% 5-year 10,242 10,308 9,279 -0.20% -0.20% -0.23% 10-year 11,451 11,744 10,713 -0.17% -0.20% -0.18% 29_Inglis-Flowerdale 2-year 7,650 7,596 6,738 -1.41% -1.40% -1.14% 5-year 10,179 10,440 9,279 -1.70% -1.38% -1.37% 10-year 12,714 12,650 11,876 -1.17% -1.45% -1.70% 30_Cam 2-year 3,536 3,488 3,109 -0.23% -0.37% -0.32% 5-year 4,595 4,683 4,193 -0.29% -0.42% -0.44% 10-year 5,710 5,728 5,239 -0.36% -0.36% -0.36% 31_Emu 2-year 4,035 4,008 3,742 -0.37% -0.35% -0.48% 5-year 5,131 5,208 4,723 -0.33% -0.33% -0.29% 10-year 6,252 5,814 5,522 -0.48% -0.46% -0.38% 32_Blythe 2-year 4,591 4,520 4,186 -1.79% -1.84% -2.72% 5-year 6,577 6,666 6,051 -1.96% -2.45% -1.93% 10-year 7,439 7,525 6,790 -2.19% -2.24% -2.11%

6 Conclusions

The Arthur-Inglis-Cam region has a mean annual flow of 4789 GL/year, and a low level of extraction with a mean annual extraction of 92.6 GL/year (1.9 percent of total water in the region). The Emu catchment has the greatest level of extraction (31.5 GL/year or 15 percent of total water in the Emu catchment) due to requirements for water from industry and town water supplies.

The volume of extracted water in the region is not expected to reduce significantly under future climate (Scenario C) relative to historical climate (Scenario A). The largest impact is seen in the driest years. In comparison to extractions, it is projected that future climate has a greater impact on total end-of-system (EOS) flows.

Peak flows were evaluated for return periods of two, five and ten years. They are projected to decrease for all return periods evaluated under Scenario Cdry relative to Scenario A in all catchments. Peak flows are projected to increase in some catchments and decrease in others under scenarios Cwet and Cmid relative to Scenario A.

Under the recent climate (Scenario B), the monthly mean flow is lower than the long-term mean in all catchments in all months with the exception of September and October. The flow duration curves show that flows under recent climate have generally been lower than the long-term mean over the full range of flows. The mean volume of water extracted decreases from 91 GL/year under Scenario A to 89 GL/year under Scenario B. The volume of non-extracted water decreases in all catchments under Scenario B relative to Scenario A by a mean of 656 GL/year over the region as a whole.

Future development in the Arthur-Inglis-Cam region includes a projected increase of 75 km2 in commercial forestry plantations. This has the effect of taking total forest cover from 6 percent of the region to 7 percent of the region by 2030. The majority of this projected increase is in the north-east of the region. The largest change in mean annual inflows under Scenario D relative to Scenario C is in the Blythe catchment with a predicted reduction of 3.7 percent. Reductions in inflows for the region as a whole are minimal, as are impacts on EOS flows.

7 References

Catchment Simulation Solutions (2009) Catchment-Sim. Viewed 10 September 2009, . CSIRO (2008) Water availability in the Murrumbidgee. A report to the Australian Government from the CSIRO Murray-Darling Basin Sustainable Yields Project. CSIRO, Australia. Department of Primary Industries, Parks, Water and Environment (2009) Applying for a Water Licence. Department of Primary Industries, Parks, Water and Environment, Hobart. Viewed 6 August 2009, . Graham B, Hardie S, Gooderham J, Gurung S, Hardie D, Marvanek S, Bobbi C, Krasnicki T and Post DA (2009) Ecological impacts of water availability for Tasmania. A report to the Australian Government from the CSIRO Tasmania Sustainable Yields Project, CSIRO Water for a Healthy Country Flagship, Australia. Kisters (2009) Hydstra/MO network modelling, Kisters Pioneering Technologies. Viewed 10 August 2009, . Knoop (2000) North Forests Burnie: Burnie Mill Water Supply System - Surveillance Inspection of Dams and Associated Infrastructure, Hydro Tasmania Report TAS-0200-SF-001, for North Forests Burnie. Hydro Tasmania, Hobart. Ling FLN, Gupta V, Willis M, Bennett JC, Robinson KA, Paudel K, Post DA and Marvanek S (2009a) River modelling for Tasmania. Volume 1: the Arthur-Inglis-Cam region. A report to the Australian Government from the CSIRO Tasmania Sustainable Yields Project, CSIRO Water for a Healthy Country Flagship, Australia. Ling FLN, Gupta V, Willis M, Bennett JC, Robinson KA, Paudel K, Post DA and Marvanek S (2009b) River modelling for Tasmania. Volume 2: the Mersey-Forth region. A report to the Australian Government from the CSIRO Tasmania Sustainable Yields Project, CSIRO Water for a Healthy Country Flagship, Australia. Ling FLN, Gupta V, Willis M, Bennett JC, Robinson KA, Paudel K, Post DA and Marvanek S (2009c) River modelling for Tasmania. Volume 3: the Pipers-Ringarooma region. A report to the Australian Government from the CSIRO Tasmania Sustainable Yields Project, CSIRO Water for a Healthy Country Flagship, Australia. Ling FLN, Gupta V, Willis M, Bennett JC, Robinson KA, Paudel K, Post DA and Marvanek S (2009d) River modelling for Tasmania. Volume 4: the South Esk region. A report to the Australian Government from the CSIRO Tasmania Sustainable Yields Project, CSIRO Water for a Healthy Country Flagship, Australia. Ling FLN, Gupta V, Willis M, Bennett JC, Robinson KA, Paudel K, Post DA and Marvanek S (2009e) River modelling for Tasmania. Volume 5: the Derwent-South East region. A report to the Australian Government from the CSIRO Tasmania Sustainable Yields Project, CSIRO Water for a Healthy Country Flagship, Australia. Post DA, Chiew FHS, Teng J, Vaze J, Yang A, Mpelasoka F, Smith I, Katzfey J, Marston F, Marvanek S, Kirono D, Nguyen K, Kent D, Donohue R, Li L and McVicar T (2009) Production of climate scenarios for Tasmania. A report to the Australian Government from the CSIRO Tasmania Sustainable Yields Project, CSIRO Water for a Healthy Country Flagship, Australia. Viney NR, Post DA, Yang A, Willis M, Robinson KA, Bennett JC, Ling FLN and Marvanek S (2009) Rainfall-runoff modelling for Tasmania. A report to the Australian Government from the CSIRO Tasmania Sustainable Yields Project, CSIRO Water for a Healthy Country Flagship, Australia. Willis M. (2008) TasCatch Finalisation Report – Stage 1 & Stage 2. HTC Report Consult-20294, for Department of Primary Industries and Water. Hydro Tasmania Consulting, Hobart. Willis M, Bennett J, Robinson K, Ling F, Gupta V (2009) Tasmania Sustainable Yields River Modelling Methods Report. Hydro Tasmania Consulting, Hobart. in prep.

Tasmania Sustainable Yields Project reports

Region reports CSIRO (2009) Water availability for Tasmania. Report one of seven to Ling FLN, Gupta V, Willis M, Bennett JC, Robinson KA, Paudel K, the Australian Government from the CSIRO Tasmania Post DA and Marvanek S (2009) River modelling for Sustainable Yields Project, CSIRO Water for a Healthy Tasmania. Volume 1: the Arthur-Inglis-Cam region. A report to Country Flagship, Australia. the Australian Government from the CSIRO Tasmania Sustainable Yields Project, CSIRO Water for a Healthy CSIRO (2009) Climate change projections and impacts on runoff for Country Flagship, Australia. Tasmania. Report two of seven to the Australian Government from the CSIRO Tasmania Sustainable Yields Project, CSIRO Ling FLN, Gupta V, Willis M, Bennett JC, Robinson KA, Paudel K, Water for a Healthy Country Flagship, Australia. Post DA and Marvanek S (2009) River modelling for Tasmania. Volume 2: the Mersey-Forth region. A report to the CSIRO (2009) Water availability for the Arthur-Inglis-Cam region. Australian Government from the CSIRO Tasmania Sustainable Report three of seven to the Australian Government from the Yields Project, CSIRO Water for a Healthy Country Flagship, CSIRO Tasmania Sustainable Yields Project, CSIRO Water for Australia. a Healthy Country Flagship, Australia. Ling FLN, Gupta V, Willis M, Bennett JC, Robinson KA, Paudel K, CSIRO (2009) Water availability for the Mersey-Forth region. Report Post DA and Marvanek S (2009) River modelling for four of seven to the Australian Government from the CSIRO Tasmania. Volume 3: the Pipers-Ringarooma region. A report Tasmania Sustainable Yields Project, CSIRO Water for a to the Australian Government from the CSIRO Tasmania Healthy Country Flagship, Australia. Sustainable Yields Project, CSIRO Water for a Healthy CSIRO (2009) Water availability for the Pipers-Ringarooma region. Country Flagship, Australia. Report five of seven to the Australian Government from the Ling FLN, Gupta V, Willis M, Bennett JC, Robinson KA, Paudel K, CSIRO Tasmania Sustainable Yields Project, CSIRO Water for Post DA and Marvanek S (2009) River modelling for a Healthy Country Flagship, Australia. Tasmania. Volume 4: the South Esk region. A report to the CSIRO (2009) Water availability for the South Esk region. Report six of Australian Government from the CSIRO Tasmania Sustainable seven to the Australian Government from the CSIRO Yields Project, CSIRO Water for a Healthy Country Flagship, Tasmania Sustainable Yields Project, CSIRO Water for a Australia. Healthy Country Flagship, Australia. Ling FLN, Gupta V, Willis M, Bennett JC, Robinson KA, Paudel K, CSIRO (2009) Water availability for the Derwent-South East region. Post DA and Marvanek S (2009) River modelling for Report seven of seven to the Australian Government from the Tasmania. Volume 5: the Derwent-South East region. A report CSIRO Tasmania Sustainable Yields Project, CSIRO Water for to the Australian Government from the CSIRO Tasmania a Healthy Country Flagship, Australia. Sustainable Yields Project, CSIRO Water for a Healthy Country Flagship, Australia. Technical reports Post DA, Chiew FHS, Teng J, Vaze J, Yang A, Mpelasoka F, Smith I, Graham B, Hardie S, Gooderham J, Gurung S, Hardie D, Marvanek S, Katzfey J, Marston F, Marvanek S, Kirono D, Nguyen K, Bobbi C, Krasnicki T and Post DA (2009) Ecological impacts of Kent D, Donohue R, Li L and McVicar T (2009) Production of water availability for Tasmania. A report to the Australian climate scenarios for Tasmania. A report to the Australian Government from the CSIRO Tasmania Sustainable Yields Government from the CSIRO Tasmania Sustainable Yields Project, CSIRO Water for a Healthy Country Flagship, Project, CSIRO Water for a Healthy Country Flagship, Australia. Australia. Harrington GA, Crosbie R, Marvanek S, McCallum J, Currie D, Viney NR, Post DA, Yang A, Willis M, Robinson KA, Bennett JC, Richardson S, Waclawik V, Anders L, Georgiou J, Middlemis H Ling FLN and Marvanek S (2009) Rainfall-runoff modelling for and Bond K (2009) Groundwater assessment and modelling Tasmania. A report to the Australian Government from the for Tasmania. A report to the Australian Government from the CSIRO Tasmania Sustainable Yields Project, CSIRO Water for CSIRO Tasmania Sustainable Yields Project, CSIRO Water for a Healthy Country Flagship, Australia. a Healthy Country Flagship, Australia.

Enquiries More information about the CSIRO Tasmania Sustainable Yields Project can be found at . This information includes the full terms of reference for the project and all associated reporting products. More information about the Water for the Future Plan of the Australian Government can be found at .