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General Purpose Water Accounting Report 2010–2011

Gwydir Catchment

Publisher

NSW Department of Primary Industries

NSW Office of Water

Level 18, 227 Elizabeth Street GPO Box 3889 Sydney NSW 2001

T 02 8281 7777 F 02 8281 7799

[email protected]

www.water.nsw.gov.au

The NSW Office of Water manages the policy and regulatory frameworks for the state’s surface water and groundwater resources, to provide a secure and sustainable water supply for all users. It also supports water utilities in the provision of water and sewerage services throughout New South Wales. The Office of Water is a division of the NSW Department of Primary Industries.

General Purpose Water Accounting Report 2010–2011: Gwydir CatchmentDecember 2011

ISBN 978 0 7313 3969 3

Acknowledgment

Soil data for groundwater methodologies provided by the Natural Resources Data Programs (soils) unit of the former NSW Department of Environment, Climate Change and Water.

This report may be cited as:

Burrell M., Moss P., Green D., Ali A., Petrovic J., Nguyen K. (2011) General Purpose Water Accounting Report 2010–2011: Gwydir Catchment, NSW Department of Primary Industries, Sydney

Cover photo: Gwydir River at Yarraman Bridge

© State of New South Wales through the Department of Trade and Investment, Regional Infrastructure and Services, 2011

This material may be reproduced in whole or in part for educational and non-commercial use, providing the meaning is unchanged and its source, publisher and authorship are clearly and correctly acknowledged.

Disclaimer: While every reasonable effort has been made to ensure that this document is correct at the time of publication, the State of New South Wales, its agents and employees, disclaim any and all liability to any person in respect of anything or the consequences of anything done or omitted to be done in reliance upon the whole or any part of this document.

Maps: The maps are to be used as a general guide for regional and local scale natural resource planning and management only, not for the assessment of specific sites which can only be assessed by investigation specific to those sites.

The maps are published by the NSW Office of Water. While every reasonable effort has been made to ensure the accuracy of the information contained in the maps, you should only satisfy yourself as to the accuracy of the information before relying on it.

NOW 11_356

General Purpose Water Accounting Report 2010-2011 – Gwydir catchment

Background Water accounting across Australia is undergoing major reform resulting from agreements under

the National Water Initiative which recognises the need for a standardised, cohesive and comparable approach. A stocktake report undertaken in 2006 found that current water reporting was being developed in an ad-hoc fashion and recommended the need for total accounting reform whereby

water accounting would be developed as a discipline comparable to that of financial accounting.

In line with this recommendation the Water Accounting Standards Board (WASB) was formed with the task of implementing a national standard for water accounting. This process has resulted in the

publication of the ‘Exposure Draft of Australian Water Accounting Standard 1 (ED AWAS 1)’ which defines the structure for preparing a ‘General Purpose Water Accounting Report’ (GPWAR)’, and following a consultation and review phase will transition to the Australian Water Accounting Standard

(AWAS)

This document is a GPWAR on the regulated component of the Gwydir River for the 2010–11 water year, prepared by the NSW Office of Water under the ED AWAS 1. The GPWAR aims to provide a

consolidated and informative summary of the water resource and water management that occurred within the valley for the reporting period.

A General Purpose Water Accounting Report prepared in accordance with the ED AWAS 1 contains:

• A contextual statement detailing the climate and water management in place for the reporting period

• A statement of Water Assets and Water Liabilities

• A statement of Change in Water Assets and Water Liabilities

• A statement of Physical Water Flows

• Disclosures/Notes – A section of notes referenced to line items within the above statements

that explain in detail the source of the data, how the number was derived and the expected uncertainty associated with the number. This section also contains reconciliation statements required by the ED AWAS 1

• An assurance statement

• An accountability statement

i | NSW Office of Water, December 2011


Table of Contents

Background............................................................................................................................................i

Contextual Statement.......................................................................................................................... 1

1 ................................................................................................................. 2 Contextual Statement1.1 ............................................................................................................... 2 Gwydir catchment1.2 ....................................................... 3 Geographic boundaries of the Gwydir reporting entity

Surface water ...................................................................................................................... 3 Groundwater ....................................................................................................................... 3

1.3 ................................................................................................................................ 6 Climate

Dam inflows......................................................................................................................... 9 1.4 ...................................................................................................... 11 Significant flow events1.5 ................................................................................................................................. 11 Policy

Surface water .................................................................................................................... 11 Groundwater ..................................................................................................................... 11

1.6 ..................................................................................................................... 12 Management

Surface water .................................................................................................................... 12 Groundwater ..................................................................................................................... 13

1.7 ......................................................................................................... 15 Environmental water

Held Environmental Water ................................................................................................ 15 Planned Environmental Water .......................................................................................... 15 Environmental watering events in 2010-11....................................................................... 15

Water Accounting Statements ......................................................................................................... 17 Water Accounting Statement Descriptions.................................................................................. 18 Other statement descriptions ...................................................................................................... 19 Significant water accounting policies .......................................................................................... 20 Quantification of data .................................................................................................................. 22 Accountability Statement............................................................................................................. 23 Water Assets and Water Liabilities ............................................................................................. 24 Changes in Water Assets and Water Liabilities .......................................................................... 25 Physical Flows Mass Balance Diagram (2010-11) ..................................................................... 27

Note disclosures................................................................................................................................ 28 Reconciliation and future prospect descriptions ......................................................................... 29 Note 1 - Surface water storage ................................................................................................... 31 Note 2 - River channel storage ................................................................................................... 33 Note 3 - Groundwater storage..................................................................................................... 35 Note 4 - Allocation accounts........................................................................................................ 38 Note 5 - Storage inflow................................................................................................................ 41 Note 6 - Storage evaporation and storage rainfall ...................................................................... 43 Note 7 - River evaporation and river rainfall................................................................................ 44 Note 8 - Tributary inflow .............................................................................................................. 45 Note 9 - Ungauged runoff estimate ............................................................................................. 48 Note 10 - Groundwater................................................................................................................ 49 Note 11 - Dam releases, river inflow from dam releases ............................................................ 54 Note 12 – Flow to Wetlands ........................................................................................................ 55 Note 13 – End of System Flows.................................................................................................. 57 Note 14 – Replenishment Flows ................................................................................................. 58 Note 15 – Licenced extractions................................................................................................... 59

ii | NSW Office of Water, December 2011


Note 16 – Supplementary Water................................................................................................. 61 Note 17 - Basic rights extractions ............................................................................................... 68 Note 18 - Available Water Determination (AWD) (Allocation Announcement) ........................... 69 Note 19 - Internal trading............................................................................................................. 72 Note 20 - Unaccounted difference .............................................................................................. 73 Note 21 – Held Environmental Water.......................................................................................... 74 Note 22 – Environmental Contingency Allowance ...................................................................... 77 Assurance Statement .................................................................................................................. 78

References ......................................................................................................................................... 79

Tables Table 1: Opening announcement summary.................................................................................. 12 Table 2: Summary of Supplementary flow events 2010-11.......................................................... 13 Table 3: Summary of Gwydir environmental watering events in 2010-11 ................................... 16 Table 4: Water account data accuracy estimates key .................................................................. 22

Figures Figure 1: Surface water geographical extent of the accounts.......................................................... 4 Figure 2: Groundwater area included in accounts ........................................................................... 5 Figure 3: Annual rainfall for 2010-11................................................................................................ 6 Figure 4: 2010-11 rainfall deviation from long term mean ............................................................... 7 Figure 5: Monthly rainfall compared with long-term quartiles 2010-11 ............................................ 8 Figure 6: Class A pan evaporation 2010-11 .................................................................................... 9 Figure 7: Daily inflows and rainfall at Copeton Dam 2010-11.......................................................... 9 Figure 8: Long-term inflows to Copeton Dam against mean and reporting year inflow................. 10 Figure 9: Monthly inflows to Copeton Dam for 2010-11 against long-term monthly

(simulated and backcalculated) quartiles and median (1890-2011). .............................. 10 Figure 10: Significant flow events in the Gwydir catchment 2010-11 .............................................. 11 Figure 11: Change in groundwater levels in the Lower Gwydir Groundwater Management

Area for 2010-11 (Upper Aquifer) ................................................................................... 14 Figure 12: Change in groundwater levels in the Lower Gwydir Groundwater Management

Area for 2010-11 (Lower Aquifer) ................................................................................... 14 Figure 13: Recognition of net water asset as of 30 June 2011........................................................ 20 Figure 14: Schematic diagram of accounting processes implemented for surface water ............... 21

iii | NSW Office of Water, December 2011


Abbreviations

Acronym Description

ACT Australian Capital Territory

AWAS Australian Water Accounting Standard

AWD Available Water Determination

CAIRO Computer Aided Improvements to River Operations

DECCW NSW Department of Environment, Climate Change and Water

ED AWAS 1 Exposure Draft of Australian Water Accounting Standard 1

GIS Geographic Information System

GL Gigalitres (1,000,000,000 litres)

GPWAR General Purpose Water Accounting Report

IQQM Integrated Quantity and Quality Model

ML Megalitres (1,000,000 litres)

MODFLOW Modular Three Dimensional Finite-Difference Groundwater Flow Model

NOW NSW Office of Water

NSW New South Wales

OEH NSW Office of Environment and Heritage

QLD Queensland

WASB Water Accounting Standards Board

iv | NSW Office of Water, December 2011


Glossary

Allocation The specific volume of water allocated to water allocation accounts in a given season, defined according to rules established in the relevant water plan.

Allocation assignments The transfer of water between licence holder allocation accounts as a result of a trade agreement. The assignment becomes part of the receiver’s current year allocation account water.

Allocation Account Water account attached to an access licence used to track the balance of account water.

Aquifer Soil or rock below the land surface that is saturated with water. A confined aquifer has layers of impermeable material above and below it and is under pressure. When the aquifer is penetrated by a well, the water rises above the top of the aquifer. In an unconfined aquifer, the upper water surface (water table) is at atmospheric pressure and thus is able to rise and fall.

Available Water Determination (AWD)

The process by which water is made available for use and shared amongst water users who hold a water access licence. It determines the volume of water that is to be added to an individuals licence allocation account.

Australian Water Accounting Standard (AWAS)

A national standard that prescribes the basis for preparing and presenting a General Purpose Water Accounting Report (GPWAR). It sets out requirements for the recognition, quantification, presentation and disclosure of items in a GPWAR.

Back-calculation A calculation approach using a mass balance to determine an unknown variable (used to calculate storage inflows based on balancing the change in storage volume where inflow is the only unknown).

Basic rights The non-licensed right to extract water to meet basic requirements for household purposes (non-commercial uses in and around the house and garden) and for watering of stock. It is available for anyone who has access to river frontage on their property.

Computer Aided Improvements to River Operations (CAIRO)

A spreadsheet-based water balance model used for optimising river operations (orders and releases)

Carryover The volume or share component that may be reserved by a licence holder for use in the proceeding year.

Catchment The areas of land which collect rainfall and contribute to surface water (streams, rivers, wetlands) or to ground-water. A catchment is a natural drainage area, bounded by sloping ground, hills or mountains, from which water flows to a low point.

Conveyance licence Defined licence category that provides an allowance for losses in the delivery of water.

Dead storage The volume in storage that is generally considered unavailable for use (e.g water level below release valves) due to access and often poor water quality.

v | NSW Office of Water, December 2011


Dealings A water dealing refers to a change that can be made to a licence, in particular, those arising from trading including the sale of all or part of an access licence or account water. May also include a change in location, licence category or consolidation/subdivision of licences.

Double entry accounting Double-entry accounting is a method of record-keeping that records both where money (or in this case water) comes from and where it goes. Using double-entry means that water is never gained or lost - it is always transferred from somewhere (a source account) to somewhere else (a destination account).

Effective storage The total volume of storage minus the dead storage component – the volume generally considered as useable.

Effluent Flow leaving a place or process. Sewage effluent refers to the flow leaving a sewage treatment plant. An effluent stream is one which leaves the main river and does not return.

Entity A defined geographical area or zone within the accounting region. Transactions and reports are produced for each entity.

End of system The last defined point in a catchment where water information can be measured and/or reported.

Environmental water Water allocated to support environmental outcomes and other public benefits. Environmental water provisions recognise the environmental water requirements and are based on environmental, social and economic considerations, including existing user rights.

Equity Total assets minus total liabilities

Evaporation The process by which water or another liquid becomes a gas. Water from land areas, bodies of water, and all other moist surfaces is absorbed into the atmosphere as a vapour.

Evapotranspiration The process by which water is transmitted as a vapour to the atmosphere as the result of evaporation from any surface and transpiration from plants.

Extraction The pumping or diverting of water from a river or aquifer by licensed users for a specific purpose (irrigation, stock, domestic, towns, etc). The volume is measured at the point of extraction or diversion (river pump, diversion works etc).

General Purpose Water Accounting Report (GPWAR)

A report prepared according to the Australian Water Accounting Standard. It is comprised of a number of components including a contextual statement, a Statement of Water Assets and Water Liabilities, a Statement of Change in Water Assets and Water Liabilities, a Statement of Physical Water Flows, Notes and Disclosures, and an assurance and accountability statement

General security licence A category of water access licence implemented under the Water Management Act 2000. Forms the bulk of the water access licence entitlement volume in NSW and is a low priority entitlement i.e. only receives water once essential and high security entitlements are met in the available water determination process.

Groundwater Water location beneath the ground in soil pore spaces and in the fractures of rock formations.

vi | NSW Office of Water, December 2011


High security licence A category of licence water access licence implemented under the Water Management Act 2000. Receives a higher priority than general security licences but less priority than essential requirements in the available water determination process.

HYDSTRA database A database used by NSW Office of Water to store continuous time series data such as river flow, river height, and water quality.

Inflows Surface water runoff and deep drainage to groundwater (groundwater recharge) and transfers into the water system (both surface and groundwater) for a defined area.

Inter-valley trade Trade of licence holder allocation account water, via allocation assignment, from one catchment to another catchment (or state).

Intra-valley trade Trade of licence holder allocation account water, via allocation assignment, within the same catchment.

Licence Administration System (LAS)

The system used by NSW Office of Water to manage water access licence information and transaction.

Liability A legally binding obligation to settle a debt.

Median The middle point of a distribution, separating the highest half of a sample from the lowest half.

Non-physical transaction An accounting transaction representing a process that is not a component of the water cycle (e.g. an available water determination).

Physical transaction An accounting transaction representing a process of the water cycle (e.g. a extraction)

Recharge Groundwater recharge is a hydrologic process where water drains downward from surface water to groundwater. Groundwater is recharged naturally by rain, floods and snow melt and to a smaller extent by drainage directly from surface water (such as rivers and lakes).

Regulated river A river system where flow is controlled via one or more major man-made structures e.g. dams and weirs. For the purposes of the Water Management Act 2000 a regulated river is one that is declared by the Minister to be a regulated river. Within a regulated river system licence holders can order water against a held entitlement.

Replenishment flows Flows provided along effluent systems downstream of a water source to supply water for household, town use and stock.

Return inflows Water that has been diverted from a river by a water user and is then returned to the river after use (e.g. can include non-consumptive uses, such as hydropower, cooling water for industry or water for aquaculture). This water is included as an inflow to the basin because the water is available to be diverted downstream or will pass the basin outlet.

Share component An entitlement to water specified on the access licence, expressed as a unit share or in the case of specific purpose licences (eg. local water utility, major water utility and domestic and stock) a volume in megalitres. The amount of water a licence holder is allocated as a result of an available water determination and the amount they can take in any year is based on their share component.

vii | NSW Office of Water, December 2011

http://en.wikipedia.org/wiki/Hydrology

http://en.wikipedia.org/wiki/Water

http://en.wikipedia.org/wiki/Surface_water

http://en.wikipedia.org/wiki/Groundwater

http://en.wikipedia.org/wiki/Rain

http://en.wikipedia.org/wiki/Snow


viii | NSW Office of Water, December 2011

Steady State A condition in a physical groundwater system where the volume does not change over time, or in which any one change in volume is continually balanced by another.

Storage A state-owned dam, weir or other structure which is used to regulate and manage river flows in the catchment and the water bodies impounded by these structures.

Storage discharge The volume of water released from storage in a specified time frame.

Storage reserve Proportion of water in a storage reserved in the resource assessment process for future essential or high security requirements (e.g. town water).

Storage volume The total volume of water held in storage at a specified time.

Supplementary water Unregulated river flow available for extraction under a supplementary licence.

Surface water All water that occurs naturally above ground including rivers, lakes, reservoirs, creeks, wetlands and estuaries.

Translucent flow The release of an agreed percentage of an incoming flow event from a dam for environmental purposes immediately downstream of the dam.

Transparent flow The release of all or part of an incoming flow event from a dam for environmental purposes at one or more sites downstream of the dam.

Tributary A smaller river or stream that flows into a larger river or stream. Usually a number of smaller tributaries merge to form a river.

Uncontrolled flow Water permitted to be extracted without debt under a general security access licence during a supplementary flow event. The extracted water may be progressively debited to the general security account if water availability exceeds predefined levels.

Ungauged catchment A catchment without a flow gauge to accurately record stream flows. Modelled estimates must be used to approximate the contribution of ungauged catchments to the main river.

Water accounting The systematic process of identifying, recognising, quantifying, reporting, assuring and publishing information about water, the rights or other claims to that water, and the obligations against that water

Water assets The physical water held in storage, as well as any claims to water that are expected to increase the future water resource (e.g. external water entering the system through intervalley trading).

Water liabilities Claims on the water assets of the water report entity including water that has been allocated to licence holder accounts or environmental accounts but yet to be taken at the end of the reporting period.

Water sharing plan A water management plan that defines the rules for sharing of water within a region under the Water Management Act 2000.


Contextual Statement

1 | NSW Office of Water, December 2011


1 Contextual Statement The contextual statement is prepared under the Exposure Draft of Australian Water Accounting

Standards 1 (ED AWAS 1), as defined by the Water Accounting Standards Board (WASB).

“The Contextual Statement shall provide information that enables users to understand the physical and administrative aspects of the water report entity. It shall contain contextual information about the

water assets and water liabilities of the water report entity, including any conditions that have an impact on the management of those water assets and water liabilities” Paragraph 48 (ED AWAS 1).

The contextual statement descriptive text is specific to the period being presented in the accounts

which is 2010-11.

1.1 Gwydir catchment The Gwydir River is part of the Murray-Darling drainage basin in northern NSW. Covering an area of 26,600 km2, the catchment extends 670 km from the Great Dividing Range to the Barwon River near Collarenebri. It is separated from the Border Rivers catchment to the north by the Mastermans Range

and from the Namoi Catchment to the south by the Nandewar Range.

From its headwaters near Guyra and Uralla, around 1,200 metres above sea level, the Gwydir River flows north-west through steep-sided valleys. It is joined by the Horton River, the largest tributary

flowing north from the Nandewar Range, before it enters the alluvial plains near Gravesend. West of Pallamallawa, the valley widens into an almost completely flat floodplain where the elevation is generally less than 200 metres. Through this flat landscape the Gwydir flows slowly westward

between low natural levee banks towards the Barwon River.

Downstream of Moree is an alluvial fan covering 200 km2, where extensive floodplain wetlands known as the Lower Gwydir wetlands have developed. These wetlands provide valuable habitat for

waterbirds, and are listed as a site of international significance under the Ramsar Convention. The lower half of the basin is characterised by numerous anabranches and effluents, the most significant being the Mehi River and Moomin Creek to the south and the Carole-Gil Gil Creek system to the north.

The dominant land uses in the valley are livestock grazing and dryland agriculture which together cover 90 per cent of the catchment. The self-mulching black soils of the lower valley have been extensively developed for irrigated agriculture. Around 1,000 km2 is used to grow crops such as

cotton, cereals and oilseeds. Most of the summer crops such as cotton are irrigated, whilst much of the winter demand is met by rainfall.

Irrigation water, town water supplies for Bingara and Gravesend and environmental releases for the

Lower Gwydir wetlands are supplied from Copeton Dam, the major storage in the valley. Most irrigation diversions occur below Pallamallawa, facilitated by a network of weirs and regulators on the Gwydir River and its effluents.

The Gwydir catchment is part of the lands originally occupied by the Kamilaroi people. There are now over 26,000 people living within the catchment. The largest town is Moree (8,000 people) which is the main commercial centre for the surrounding agricultural areas. It is also a major transport and tourism

hub, being located at the junction of the Gwydir and Newell Highways. There are a number of smaller towns of 1,000–2,000 people - Uralla and Guyra in the New England tablelands, and Bingara and Warialda in the middle of the catchment. Smaller villages include Bundarra, Delungra, Pallamallawa

and Tingha which have populations of 300–700 people.




1.2 Geographic boundaries of the Gwydir reporting entity

Surface water The accounting extent for surface water is illustrated in Figure 1. The accounted river extent is the Gwydir River from downstream Copeton Dam to Millewa, the Mehi River from its initial effluent from

the Gwydir River to near Collarenebri, Mallowa Creek, Moomin Creek, Carole Creek and Gil Gil Creek from its junction with Carole Creek to Gil Gil Creek at Galloway. It should be noted that the nominated component of Gil Gil Creek extends beyond the surface water catchment boundary of the Gwydir and

into the Border Rivers catchment as orders in this section are met using resources from the Gwydir.

All licences that are managed under the water sharing plan for the Gwydir Regulated River Water Source are considered.

Groundwater The accounting extent for groundwater is illustrated in Figure 2. The NSW Office of Water has developed a suite of options for determining groundwater accounting information. As a result of this, within this defined area, the methodologies used to estimate groundwater budget parameters and also

the number of water budget parameters able to be defined varies considerably.

Groundwater balances for the 2010-11 reporting period utilised data from one method only (Method B) which is detailed in Note 10 of this GPWAR. It is intended however, to increase the extent of

groundwater coverage in future Gwydir GPWARs.

For the area where Method B was utilised (the Lower Gwydir Groundwater Management Area), a full water balance was achieved and the following components reported in the accounting statements:

• assumed groundwater volume asset (twice licensed share component on 30 June 2008)

• recharge (rainfall, irrigation, flood)

• aquifer gain from river

• aquifer loss to river

• lateral flows

• pumping

• evapotranspiration

Exclusions

Only the physical components of the Lower Gwydir Groundwater Management Area have been included in this GPWAR i.e. no licence account balances, available water determinations, trading etc are provided.


Figure 1: Surface water geographical extent of the accounts



Figure 2: Groundwater area included in accounts



1.3 Climate The first half of 2010-11 saw a break in the drought conditions that have dominated the Gwydir catchment since 2005. While the wet conditions were not as pronounced as that experienced by

valleys in the south of the state, it did bring a steady increase in Copeton Dam levels from just 7 per cent capacity in August 2010 to 50 per cent by the end of December 2010, and a small flood event in October provided significant benefits along the river and into the Lower Gwydir wetlands.

Annual rainfall exceeded 1,000 mm for the year in the storage catchment area east of Bundarra, with annual totals to around 1,500 mm in the highest parts of the catchment north east of Bundarra (Figure 3). Above average rainfall was widespread across the catchment with falls commonly between 100

and 400 mm above the long term average comparison period (1961-1990) (Figure 4). The greatest variation occurred in the upper catchment to the north and east of Bundarra where annual rainfall was 200-400 mm above average. Rainfall through the middle of the catchment (around Moree and to the

south) was close to average with variation from the long term mean being within the range of 0-100 mm.

Figure 3: Annual rainfall for 2010-11 Layer source: Bureau of Meteorology



Figure 4: 2010-11 rainfall deviation from long term mean Layer source: Bureau of Meteorology

The Gwydir catchment received higher than average rainfall from winter through to mid-summer, with monthly totals during this period well into the wettest historic quartile (within the highest 25% of monthly rainfalls for the historical period) (Figure 5). With the exception of Collarenebri in January

2011, which fell just inside the driest quartile for the historic record, all monthly totals at Collarenebri, Pallamallawa and Bundarra, exceeded the driest quartile of the historic record.

Class A pan evaporation is measured at Inverell in the upper catchment and Moree in the middle of

the catchment. At both sites cooler than average daytime temperatures and higher rainfalls kept daily pan evaporation below the monthly average for most of the year, but particularly throughout spring and early summer (Figure 6). In December there was a very noticeable variation from the mean

(around 2 mm below average at Inverell and 3 mm below average at Moree). This was due to significantly cooler conditions which resulted in mean maximum temperatures 3-4°C below the December average. Evaporation in January and February was consistent with average conditions but

fell below the long term average again in March and April.



Figure 5: Monthly rainfall compared with long-term quartiles 2010-11



Figure 6: Class A pan evaporation 2010-11

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Moree 2010-11 Moree mean (1995-2011) Inverell 2010-11 Inverell mean (1965-2011)

Dam inflows The long drought that had affected the Gwydir valley continued into the commencement of 2010-11 with Copeton Dam starting at just 7 per cent capacity (99,967 ML). Resources improved however, and

significant inflows in the first half of the year resulted in the storage finishing the year at 50 per cent capacity (690,262 ML).

Six consecutive events exceeding 15,000 ML/day entered Copeton between August and January, the

maximum of these reaching just over 30,000 ML/day in mid October (Figure 7). Storage inflows for the year totalled 748,000 ML, the highest inflows to be received in Copeton Dam since 1998-99 (Figure 8). Inflows were above the long term median in all months of the year with inflows from August to January

being in the wettest quartile for these months (for simulated and back-calculated records since 1890).

Figure 7: Daily inflows and rainfall at Copeton Dam 2010-11

Daily inflows and rainfall at Copeton Dam 2010-11

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Figure 8: Long-term inflows to Copeton Dam against mean and reporting year inflow

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Figure 9: Monthly inflows to Copeton Dam for 2010-11 against long-term monthly (simulated and backcalculated) quartiles and median (1890-2011).

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1.4 Significant flow events A series of flow events were generated in the Gwydir catchment between August and January as a

result of the frequent rain storms that occurred during this period (Figure 10). The flows at Bundarra reflect the conditions in the upper catchment which generated significant inflows to Copeton Dam (discussed in the previous section). None of these inflows were passed through Copeton Dam

(releases were kept at 35-50 ML/d until January 2011) and hence the flow peaks recorded at Yarraman Bridge were the result of tributary inflows between Copeton Dam and Moree.

During August-September there were four minor events at Yarraman Bridge within the range of 5,000-

10,000 ML/d. The largest event of the year occurred in mid-October which peaked at over 28,000 ML on 17 October. This flow was the first significant flow event at Yarraman Bridge since 2005.

Steady inflows of water commenced to the Lower Gwydir wetlands (as shown by flows at Brageen

Crossing) in August 2010 and continued until late September. Inundation of the wetlands between August and October attracted a variety of waterbird species which began breeding. For further details of environmental watering events see Section 1.7.

Figure 10: Significant flow events in the Gwydir catchment 2010-11

0

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Gwydir River at Bundarra Gwydir River at Yarraman Bridge Gwydir River at Brageen Crossing

1.5 Policy

Surface water The surface water area reported in the GPWAR was operated under the Water Sharing Plan for the

Gwydir Regulated River Water Source. The plan includes rules for protecting the environment, extractions, managing licence holders' water accounts, and water trading in the plan area. The plan and a guide outlining the key provisions and rules of the plan can be located at the NSW Office of

Water website (www.water.nsw.gov.au)

Groundwater The Lower Gwydir alluvial aquifer was operated under the Water Sharing Plan for the Lower Gwydir Groundwater Source. The plan and a guide outlining the key provisions and rules of the plan can be

located at the NSW Office of Water website (www.water.nsw.gov.au). All other areas continued to be operated in line with the legislation of the Water Act 1912.


http://www.water.nsw.gov.au/



1.6 Management

Surface water The 2010-11 water year commenced with relatively little water available for use. The volume of water

held in Copeton dam on the 1 July 2010 was 99,967 ML (7 per cent of capacity). While this was sufficient to provide an equivalent allocation of 1 ML per share for all high security licences, aside from the 11,025 ML carried over from 2009-10, no additional water was made available to general security

licences at that point in time.

With high rainfall throughout spring and summer water availability improved significantly. Throughout the season a cumulative total of 422,242 ML was made available to General Security licence holders,

the equivalent of 82.8 per cent of the total General Security share component in the Gwydir. The level of Copeton Dam on 30 June 2011 was 690,262 ML.

Table 1: Opening announcement summary

GWYDIR REGULATED RIVER WATER SOURCE

1 July 2010 - 30 June 2011

Date Entitlement Individual

Announcement

Allocation Volume

(ML) % of

Entitlement

Balance Available

(ML)

Non Available

(ML) Total (ML)

DOMESTIC AND STOCK Start 2,506 0 0 0

1 July 2010 2,506 AWD 100.0 % 2,506 100.00% 2,506 0 2,506 DOMESTIC AND STOCK(DOMESTIC) Start 8 0 0 0

1 July 2010 8 AWD 100.0 % 8 100.00% 8 0 8 DOMESTIC AND STOCK(STOCK) Start 230 0 0 0

1 July 2010 230 AWD 100.0 % 230 100.00% 230 0 230 LOCAL WATER UTILITY Start 3,836 (6) 0 (6)

1 July 2010 3,836 AWD 100.0 % 3,836 100.00% 3,830 0 3,830 REGULATED RIVER (GENERAL SECURITY) Start 509,665 11,015 10 11,025 REGULATED RIVER (HIGH SECURITY) Start 14,818 (11) 0 (11)

1 July 2010 14,818 AWD 1.0 ML per Share 14,818 100.00% 14,807 0 14,807

REGULATED RIVER (HIGH SECURITY)(RESEARCH) Start 60 0 0 0

1 July 2010 60 AWD 1.0 ML per Share 60 100.00% 60 0 60

SUPPLEMENTARY WATER Start 177,347 0 0 0

1 July 2010 177,347 AWD 1.0 ML per Share 177,347 100.00% 177,339 0 177,339

In the Gwydir replenishment flows up to 21,000 ML are set aside annually to provide water along

effluent streams for households, towns and stock. In 2010-11 a total of 11,514 ML of replenishment flows were delivered. A more detailed breakdown of this volume is located in Note 14 of this GPWAR.

In 2010-11 works for the Lower Gingham Domestic Water Supply Scheme were completed replacing

the open channel system with a piped water supply as part of the joint Commonwealth and State Government water efficiency programs. As a result, the 6,000 ML annual replenishments flow down



Gingham will not be required in future years, resulting in annual water savings of 900 ML which will be used to replenish the Gingham Wetlands.

Licence holders with access to supplementary water were granted 100 per cent of entitlement. Throughout 2010-11 there were eight periods of supplementary flow access, with 141,781 ML being made available to licence holders. Of this water, 137,440 ML was extracted for use.

As defined by the water sharing plan no more than 50% of the volume within a supplementary event may be made water available for extraction under supplementary water access licences. The other 50% of the event must be maintained for environmental benefit within the system. Table 2 provides a

summary of the supplementary announcements made. For details of announcements by river section see Note 16.

Table 2: Summary of Supplementary flow events 2010-11

Start Finish Total Days

Total Flow (ML)

Flow Available

for Sharing

(ML)

Environment Share

Water User

Share

Supplementary Water

Announced (ML)

Water Extracted

(ML)

31/07/2010 30/09/2010 62 155,543 117,343 50% 50% 58,653 57,456 16/10/2010 31/10/2010 16 87,358 78,808 50% 50% 38,020 36,245 14/11/2010 16/11/2010 3 2,909 1,333 50% 50% 544 542 18/11/2010 28/11/2010 11 32,855 26,828 50% 50% 13,339 13,097 03/12/2010 25/12/2010 23 64,658 50,749 50% 50% 25,032 24,398 07/01/2011 12/01/2011 6 15,859 3,653 50% 50% 1,811 1,571 13/01/2011 14/01/2011 2 9,212 5,768 50% 50% 2,782 2,568 16/06/2011 18/06/2011 3 6,003 3,453 50% 50% 1,600 1,563

TOTAL 126 374,397 287,935 141,781 137,440

Groundwater All groundwater licences in the Gwydir catchment were granted an equivalent allocation of 1 ML per

share with the exception of the Supplementary Access Licences in the Lower Gwydir Alluvium, which received an allocation of 0.714 ML per share. Under the Water Sharing Plan for the Lower Gwydir Groundwater Source, the volume of supplementary water made available will progressively be

reduced to zero at the commencement of the 2015-16 water year. In order to achieve this each year the available water determination announcement to this category of licence is reduced by 0.143 ML per unit of share component.

Overall the aquifers show minimal change in levels for the reporting period. This is an improvement from the previous few years, resulting from improved climatic conditions, where the prolonged drought had resulted in a drawing down the aquifers.

While the upper aquifer recharge increased as a result of increased surface water irrigation, increased recharge from the river and a decrease in groundwater extractions, it was offset by a significant increase in the base flow from the aquifer to the river and recharge to the lower aquifer.

The variation observed in the lower aquifer results from the concentration of pumping in specific areas within the aquifer and the slower reaction time of the lower aquifer to redistribute the recharge from the upper aquifer.



Figure 11: Change in groundwater levels in the Lower Gwydir Groundwater Management Area for 2010-11 (Upper Aquifer)

Figure 12: Change in groundwater levels in the Lower Gwydir Groundwater Management Area for 2010-11 (Lower Aquifer)



1.7 Environmental water

Held Environmental Water Held environmental water represents water that is held as part of a licensed volumetric entitlement. In

2010-11 held general security environmental water increased from a total share component of 105,612 ML to 106,617 ML while held high security environmental water increased from 0 ML to 375 ML. Delivery of held environmental water consisted of 4,727 ML held by NSW and 13,056 ML held by

the Commonwealth (see Table 3).

For a detailed breakdown of held and traded environmental water refer to Note 21.

Planned Environmental Water Planned environmental water is detailed in the Water Sharing Plan for the Gwydir River Regulated

River Water Source 2002. It consists of three main components:

A minimum flow requirement through to the Gwydir Wetlands: The flow aims to maintain wetland health by maintaining a minimum flow into the Gwydir Wetlands of up to 500 ML/d. The minimum flow

requirement is calculated as the lesser of either:

• 500 ML or;

• The total volume of water entering the Gwydir River from major tributaries being the Horton

River, Myall Creek and Hall’s Creek plus any additional flows resulting from the spilling of, or flood mitigation pre-releases from, Copeton Dam.

The minimum flow target is to be applied at Yarraman Bridge gauging station (418004) and is not to be used to off-set delivery losses, to deliver ordered water or provide domestic and stock water downstream of the Tyreel Regulator or Gingham Weir.

During 2010-11 all minimum flow targets were maintained. A total of 247 days were considered to have minimum flow targets totalling 74,970 ML. The flow adjusted for downstream orders measured at Yarraman Bridge for the corresponding period was 182,545 ML. A total of 9 days were more than 25%

below the target, these shortfalls were all made up in the month they occurred.

An Environmental Contingency Allowance (ECA): Water is put aside in Copeton Dam that can be called upon to achieve environmental benefits such as supporting bird breeding events, supporting

native fish colonies and maintaining general river ecosystem health. The amount of water that may be credited to the ECA account is determined based on the available water determinations for General Security licence holders, up to a maximum of 90,000 ML. The ECA water delivered in 2010-11 was

5,000 ML (see Table 3).

Long-term extraction limit: By limiting long-term average extractions to an estimated 392,000 ML/year this Plan ensures that approximately 66% of the long-term average annual flow in the water

source (estimated to be 1,141,000 ML/year) will be preserved and will contribute to the maintenance of basic ecosystem health. As previously discussed there is also a limit on the amount of water that can be taken from a supplementary flow event which ensures 50% of the volume remains in stream

for environmental outcomes.

Environmental watering events in 2010-11 In 2010-11 a total of 22,783 ML of water was used specifically for environmental purposes. A summary of the events, volume used and the locations where the water was used is included in Table

3.

The bulk of the environmental water was to support the inundation of the Lower Gwydir wetlands. The purpose of these actions was to prolong the inundation of the wetlands created by natural rainfall and

river flows, support the recovery of wetland vegetation and create habitat for threatened and migratory




species. The Office of Water and OEH (then DECCW) managed the water delivery and have been monitoring the ecological benefits created by the watering.

A variety of waterbirds were attracted by the wet conditions in the Lower Gwydir including 300 magpie geese, a threatened species in NSW that is often found in the Gwydir. The marsh club-rush community that forms the core of the Lower Gwydir wetlands has declined significantly in condition

and extent over the past decade. The high flows and frequent rainfall events over summer 2010-11 were optimal for the Marsh club-rush sedgeland to flower, set seed and improve condition (OEH 2011).

Table 3: Summary of Gwydir environmental watering events in 2010-11

ML delivered

Location Commence Finish NSW CEWH ECA

Total for the event

Gwydir and Gingham Wetlands above Gingham Bridge and the Goddards Lease Ramsar site

1 August 2010 3 August 2010 0 3,056 0 3,056

Gwydir Wetlands – Whittakers Lagoon – Mehi River*

10 December 2010 12 December 2010 70 0 0 70

Gwydir Wetland system

19 January 2011 21 March 2011 4,657 10,000 5,000 19,657

Total 4,727 13,056 5,000 22,783

Table Notes * The 70 ML was traded from an environmental to a non environmental licence and delivered for environmental

purpose via its infrastructure. NSW Water sourced from NSW Environmental Water Holders CEWH Water sourced from the Commonwealth Environmental Water Holder ECA Environmental Contingency Allowance accrued under the Water Sharing Plan for the Gwydir Regulated River

Water Source 2002 Source Environmental Water Use in NSW, Annual Report 2010-11, NSW Office of Environment and Heritage, 2011)


Water Accounting Statements



Water Accounting Statement Descriptions

The water accounting statements required under ED AWAS 1 comprise three statements:

• Statement of Water Assets and Water Liabilities as at 30 June 2011

• Statement of Changes in Water Assets and Water Liabilities for 1 July 2010 to 30 June 2011

• Statement of Physical Water Flows for 1 July 2010 to 30 June 2011. This has been excluded, however from this report. See the section on significant water accounting policies for further

information on this omission.

Statement of Water Assets and Water Liabilities

The Statement of Water Assets and Water Liabilities is prepared under the ED AWAS 1, as defined by the Water Accounting Standards Board.

’The Statement of Water Assets and Water Liabilities shall provide information that enables users to understand the nature and volumes of the water assets and water liabilities of a water report entity‘ (paragraph 58, WASB 2010).

In line with the above statement, this report provides an assessment of the water available in storage plus any current claims to water (water assets). This is offset by any present obligations (water liabilities) that are required to be met with these water assets. Figures from the previous reporting

period are also provided to add context. All figures are in megalitres (ML).

Water assets

Water assets for the reporting entity include not only physical water in storage, but also any claims to water that are expected to increase the future water resource. Other claims would be applicable where the entity is owed water from another external entity (e.g. intervalley trading).

Water liabilities

Water liabilities represent claims on the water assets of the water report entity. This is most apparent

in water that has been allocated to licence holder accounts or environmental accounts but yet to be taken at the end of the reporting period (account water allowed to be carried forward to the next water year). As such the figures represent the closing balances of these accounts for the reporting period. It

should be noted that there have been no groundwater liabilities accounted for in the statements for this report. It is anticipated, however that these will be incorporated to the statements in future years.

Net water assets

This is a calculated figure of total water assets minus total water liabilities.

Statement of Changes in Water Assets and Water Liabilities

This statement is prepared under the ED AWAS 1, as defined by the Water Accounting Standards Board.

“The Statement of Changes in Water Assets and Water Liabilities shall contain information that enables users to understand changes in the volumes and nature of the water report entity’s net water assets during the reporting period” (paragraph 101, WASB 2010).

The report is comprised of both physical and non-physical transactions and illustrates how the change in net water assets from the previous reporting period has eventuated. Figures from the previous reporting period are also provided in order to put the change into context.



Water asset increases

Account items that have an increasing effect on the water assets presented in the Statement of Water Assets and Water Liabilities e.g. tributary inflows and rainfall.

Water asset decreases

Account items that have a decreasing effect on the water assets presented in the Statement of Water Assets and Water Liabilities e.g. evaporation and groundwater pumping.

Water liability increases

Account items that have an increasing effect on the water liabilities presented in the Statement of

Water Assets and Water Liabilities e.g. available water determinations increase the amount of water available in the allocation liability accounts.

Water liability decreases

Account items that have a decreasing effect on the water liabilities presented in the Statement of Water Assets and Water Liabilities e.g. forfeited water reduces the amount of water available in the

allocation liability accounts.

Change in net water assets

The figure is calculated as:

+=Δ WLDWLIWADWAINWA

Where NWA = Net water assets

WAI = Water asset increases

WAD = Water asset decreases

WLI = Water liability increases

WLD = Water liability decreases

The resultant net change should be equal to the annual change in net water asset on the Statement of

Water Assets and Water Liabilities i.e. {Net Water Asset [Reporting Year] minus Net Water Asset [Reporting Year-1]}

Other statement descriptions

Two additional statements are required under ED AWAS 1:

• Accountability Statement

• Assurance Statement

Accountability Statement

The Accountability Statement is prepared under the ED AWAS 1, as defined by the Water Accounting Standards Board.

‘The Accountability Statement shall provide information that assists users to assess whether:

• the general purpose water accounting report has been prepared and presented in accordance with Australian Water Accounting Standards;

• externally-imposed requirements relevant to managing the water assets and water liabilities

of the water report entity have been complied with; and

• best practices for managing water assets and water liabilities have been applied’ (Paragraph

50 WASB, 2010)



The statement details externally imposed requirements and best practice for management, relevant to the water reporting entity for the reporting period.

Assurance Statement

The Assurance Statement is prepared under the ED AWAS 1, as defined by the Water Accounting

Standards Board.

’An explicit statement of whether the general purpose water accounting report is presented fairly in accordance with this standard shall be provided in the Assurance Statement‘ (paragraph 167, WASB

2010).

No specific Assurance Statement has been included in this report (see specific section on Assurance Statement in this report for more details).

Significant water accounting policies

The water accounting statements in this GPWAR have been prepared using an accrual basis of accounting. All figures are in megalitres (ML).

Recognition of water assets and liabilities

The water assets and water liabilities that have been recognised in these accounts are illustrated in

Figure 13 below.

Figure 13: Recognition of net water asset as of 30 June 2011

Allocation accounts that finish the water year as a negative figure as a result of over pumping must be carried over to be paid back in the following year. Under the ED AWAS 1 this could be represented as

a positive value in the Water Assets for these accounts, however here it will be presented as a negative liability with the intention of presenting a clearer and more informative statement whereby all licence allocation account balances are presented together.

Recognition of changes in water assets and liabilities

Accounting models were derived based on a physical model of the river which identified physical

transactions that impacted the water assets and to which accounting policy was applied. The adopted physical model used in this process is illustrated in Figure 14.



Figure 14: Schematic diagram of accounting processes implemented for surface water

Copeton Dam

Copeton release (decrease in water asset)

Tributary inflow (ungauged),rainfall

Evaporation, extractionsGwydir River System

Copeton Dam Inflow

Rainfall

Evaporation

River inflow (increase in water asset)

Tributary inflow (Halls Creek, Horton River, Myall Creek, Tycannah Creek, Gil Gil Creek) Gwydir River

at Millewa

Gingham Channel at Teralba

Gil Gil Creekat Galloway

Mehi River near Collarenebri

Licence Allocation Accounts

Usage

Over Ordering

Forfeiture

Available Water Determination

Trade In

Trade Out

Environmental Contingency Allowance

Usage

Forfeiture

Available Water Determination

Water Liability

Water Liability Increase

Water Liability Decrease

Water Asset

Water Asset Increase

Water Asset Decrease

Internal water trades have a net zero change in liabilities and as such would not be shown in the ‘Statement of Changes in Water Assets and Water Liabilities’. In order to show them it was necessary to consider trades as a two part transaction i.e. one being the selling and the other being the buying.

Therefore the trades appear as both a water liability increase (buyer) and a water liability decrease (seller).

Storages releases, while being a net zero transfer of water asset from the storage to the river, has

been included in the ‘Changes in Water Assets and Water Liabilities’ statement. This has been accounted as a decrease in the storage asset with a corresponding increase in the river asset.



To represent the extraction of water from the river in the ‘Change in Water Assets and Liabilities’ statement it was necessary to consider it as two specific processes firstly the physical extraction of the

water from the river and secondly the adjustment of the water liability as a result of this physical extraction. This is represented in the ‘Changes in Water Assets and Water Liabilities’ statement as a decrease in the river asset with a corresponding decrease in the water liability.

Omission of Statement of Physical Flows

The ‘Statement of Physical Flows’ has been excluded for this GPWAR as all transactions have already

been presented in the statements ‘Water Assets and Liabilities’ and ‘Changes in Water Assets and Water Liabilities’.

The introduction of a ‘Physical Flow Diagram’ that represents the physical movements of water has

been included in order to provide a clearer picture of this process.

Quantification of data

Data accuracy

It is important to recognise that the data used to account for water movement and management in the reporting entity has been obtained from a variety of sources and systems. The data ranges from

observed values where a high accuracy would be anticipated through to modelled results and estimates where accuracy can be highly variable depending on a range of factors. To address the inconsistencies in accuracy and prevent misuse of the data in the accounts, all figures in the water

accounting statements will be accompanied by an assessment of accuracy as defined in Table 4.

Table 4: Water account data accuracy estimates key

A1 = +/- 0% Data is determined rather than estimated or measured. Therefore the number contains no inaccuracies.

A = +/- 10%

B = +/- 25%

C= +/- 50%

D = +/- 100%

Data clarification

In addition to an accuracy code each figure in the accounts is cross-referenced where appropriate to a

numerically linked note where detailed information can be found relating to that figure. The notes form part of the note disclosures of this GPWAR. The information contained in the notes is reported according to the following structure:

• brief description

• data type

• policy

• data accuracy

• providing agency

• data source

• methodology

• additional information (if applicable)



Gwydir catchment

Accountability Statement

In the opinion of the undersigned:

1. The management of the water assets and water liabilities of the Gwydir water report entity have

been conducted throughout 2010-11 under the required externally-imposed requirements, including:

• Water Management Act 2000

• Water Act 1912

• Water Sharing Plan for the Gwydir Regulated River Water Source 2002

• Water Sharing Plan for the Rocky Creek, Cobbadah, Upper Horton and Lower Horton Water

Source 2003

• Water Sharing Plan for the Lower Gwydir Groundwater Source 2003

• Murray-Darling Basin Agreement 2000

2. The management of the water source has been carried out by qualified and experienced staff who have undertaken the task with due diligence.

3. The water sharing plans referred to above incorporate the following management principles:

• Water sharing and extraction limitations

• Trading of water rights

• Basic landholder rights

• Water planning and strategic initiatives

• Environmental stewardship

4. The information presented in these accounts is a faithful representation of the management and operation of the Gwydir catchment in 2010-11.

5. NSW Office of Water has to the best of its ability prepared the General Purpose Water Accounting

Report for the Gwydir water report entity for the 2010-11 water year in accordance with the ED AWAS 1.



Gwydir catchment

Water Assets and Water Liabilities

For the year ended 30 June 2011

Surface Water Assets

1.Surface Water Storage Accuracy Notes 30 June 2011 30 June 2010

Copeton Dam A 1 690,262 100,023 River B 2 1,884 234

Total Surface Water Storage (ASWS) 692,146 100,257

Change in Physical Surface Water Storage 591,889 (76,024)

Surface Water Liabilities

2.Allocation Account Balance

High Security (HS) A1 4 0 (11) Local Water Utility A1 4 0 (6) General Security A1 4 342,552 11,025

Total Allocation Account Balance (LSWS) 342,552 11,008

Change in Allocation Account Balance 331,544 (23,623)

3. Environmental Contingency Allowance (ECA) Balance

ECA A1 22 49,592 17,305

Change in ECA Balance 32,287 0

Net Surface Water Assets (ASWS – LSWS) 300,002 71,944 Change in Net Surface Water Assets 228,058 (52,401)

Groundwater Assets

4. Groundwater Storage

Lower Gwydir Alluvium A1 3 70,491 70,261

Total Groundwater Storage (AGWS) 70,491 70,261

Change in Groundwater Storage 230 (16,739)

Groundwater Liabilities (LGWS)

No groundwater liabilities have been recognised in this account

Net Groundwater Assets (AGWS - LGWS) 70,491 70,261

Change in Net Groundwater Assets 230 (16,739)



Gwydir catchment

Changes in Water Assets and Water Liabilities

For the year ended 30 June 2011 (1 of 2)

1. Changes in Surface Water Storage (Physical Water Balance)

Surface Water Storage Increases Accuracy Notes 30-Jun-11 30-Jun-10 Copeton Dam

Inflow A 5 748,261 30,804 Rainfall B 6 20,904 5,004

River Rainfall C 7 42,614 19,091 Inflow from Copeton Releases A 11 144,866 95,000 Inflow from Aquifer (Baseflow) D 10 41,897 8,886 Tributary Inflow

Gauged Tributaries A 8 312,888 14,822 Ungauged Runoff Estimate C 9 145,689 7,389

Total Surface Water Storage Increases (ISWS) 1,457,119 180,996

Surface Water Storage Decreases Copeton

Storage Release A 11 144,866 95,000 Evaporation B 6 34,060 16,255

River Evaporation C 7 90,604 67,317 Flows Leaving System

Wetlands A 12 151,634 4,917 End of System A 13 50,967 4,536 Replenishment A 14 11,514 17,479

River outflow to Aquifer D 10 54,007 24,428 Licensed extractions A 15

Domestic and Stock 1,125 1,315 Local Water Utility 2,084 2,446 High Security 7,347 9,184 General Security 97,153 28,489 Supplementary Extractions 16 137,440 5,526

Basic Rights Extractions C 17 6,000 6,000

Total Surface Water Storage Decreases (DSWS) 788,801 282,892

Unaccounted Volume (Balancing Item) (USWS) 76,429 (25,872)

Net Surface Water Storage Inflow ((ISWS - DSWS - USWS) 591,889 (76,024)

2. Changes in Allocation Accounts

Allocation Account Increases Available Water Determinations A1 18

Domestic and Stock 2,744 2,744 General Security 422,242 0 High Security 14,818 14,414 High Security (Research) 60 60 Local Water Utility 3,836 3,836

Internal Trade - Buyers A1 19 32,438 17,012

Total Allocation Increases (IAA) 500,225 38,066



Gwydir catchment Changes in Water Assets and Water Liabilities For the year ended 30 June 2011 (2 of 2)

Allocation Account Decreases Account usage (total) A 15 107,709 58,900 Account Forfeiture A 4

Domestic and Stock 1,614 1,300 General Security 297 44 High Security 98 59 High Security (Research) 60 60 Local Water Utility 1,746 1,400

Over Order Domestic and Stock 5 129 General Security 626 229 High Security 1 298

Internal Trade - Sellers A1 19 32,438 17,012 Account Balance Adjustment 0 (275) Total Allocation Account Decreases (DAA) 168,681 61,964

Net Allocation Account Balance Increase 331,544 (23,623)

3. Change in Environmental Contingency Allowance (ECA)

ECA Account Increases (IECA) Account Increase due to General Security AWD A 22 37,287 0

ECA Account Decreases (DECA) Account usage A 22 5,000 0

Net Environmental Water Allowance Increase 32,287 0

Change in Net Surface Water Assets (ISWS - DSWS - USWS - IAA + DAA - IECA + DECA) 228,058 (52,401)

4. Change in Groundwater Storage (Physical Water Balance)

Groundwater Storage Increases Method B Area D 10

Physical Groundwater Inflows Recharge 37,984 29,154 Aquifer Inflow from River 54,007 24,428

Total Groundwater Storage Increases (IGWS) 91,991 53,582

Groundwater Storage Decreases Method B Area D 10

Physical Groundwater Outflows Aquifer outflow to River 41,897 8,886 Evapotranspiration 16,932 17,042 Pumping 32,932 44,394

Total Groundwater Storage Decreases (DGWS) 91,761 70,322

Net Groundwater Storage Inflow (IGWS - DGWS) 230 (16,739)

Change in Net Groundwater Assets (IGWS - DGWS) 3 230 (16,739)




Physical Flows Mass Balance Diagram (2010-11)

Gwydir River

Evaporation: 90,604Extraction: 251,149

River outflow to Aquifer: 54,007Replenishment Flows 11,514

River Outflows

Rainfall: 42,614Gauged Inflow: 312,888

Ungauged Inflow: 145,689River Inflow from Aquifer: 41,897

River Inflows

Unaccounted difference

76,429

01/07/10: 23430/06/11: 1,884 Change: 1,650

Inflow

Evaporation

20,904

34,060

748,261

Rainfall

Release 144,866

01/07/10: 100,02330/06/11: 690,262

Change: 590,239

Copeton Dam Volume

All figures in megalitres

Marsh/Wetlan

Major Storage

Outflow

Inflow

Carole Creek

50,967

End of System

Mehi River

Flow to Gwydir Wetlands151,634


Note disclosures



Reconciliation and future prospect descriptions

This information is included in the note disclosures for this GPWAR according to the following

requirement of the water accounting standards defined in ED AWAS 1:

‘The following information shall be disclosed in the notes:

a) A reconciliation of the change in water storage presented in the Statement of Physical Water Flows

to the change in net water assets presented in the Statement of Changes in Water Assets and Water Liabilities;

b) The items comprising both opening water storage and closing water storage presented in the

Statement of Physical Water Flows; and

c) A reconciliation of closing water storage presented in the Statement of Physical Water Flows to total water assets presented in the Statement of Water Assets and Water Liabilities’ (Paragraph 139,

ED AWAS 1, WASB, 2010).

Further to this it is required to include information that will assist the user to understand the future propects of the water report entity by defining the water assets available to settle water liabilities and

future commitments within 12 months of the reporting date. This is calculated according to the formula:

SWA = WARP + WAI - WA NA - WL E – FC (All components are defined in the reconciliation of water assets available to settle water liabilities and future commitments within 12 months of reporting date).

Reconciliation of change in net water asset to net change in physical water storage

2011 2010

ML ML

CHANGE IN NET SURFACE WATER ASSETS 228,058 (52,401)

Non-physical adjustments

Net Change in Allocation Accounts 331,544 (23,623)

Net Change in Claims to Water: ECA 32,287 0

363,831 (23,623)

NET CHANGE IN PHYSICAL SURFACE WATER STORAGE 591,889 (76,024)

Reconciliation of closing water storage to total surface water assets

2010 2009

ML ML

CLOSING WATER STORAGE

Surface Water Storage 692,146 100,257

TOTAL SURFACE WATER ASSETS 692,146 100,257

Notes: All figures can be derived from or found directly in the Water Accounting Statements of the General Purpose Water Accounting Report.



Water assets available to settle water liabilities and future commitments within 12 months of reporting date

(ML) Note (ML)

TOTAL WATER ASSETS AS AT 30 June 2010 (WARP) 692,146

Plus: Water Asset increases within 12months of reporting date (WAI)

Minimum Storage Inflow 50,000 (a) 50,000

Less: Water assets not available to be accessed and taken or delivered within 12 months of reporting date. (WANA)

Storage Net Evaporation 46,630 (b)

Delivery Loss 118,460 (c)

Delivery Loss Essential Requirements 10,000 (d)

Essential Requirements 2012-13 80,500 (e)

End of System Flows 16,000 (f)

Minimum Storage Release 5,000 (g)

Dead Storage 19,000 1 295,590

Water assets available to be accessed and taken or delivered within 12 months of reporting date.

446,556

Less: Water liabilities and future commitments expected to be settled within 12 months of the reporting date.

Water Liabilities expected to be delivered within 12 months of reporting date. (WLE)

Surface Water Carryover 342,552 4 342,552

ECA 49,592 22 49,592

Future Commitments expected to be delivered within 12 months of reporting date. (FC)

Indicative Allocations and Basic Rights (h)

Towns 3,836 4

Domestic and Stock 2,744 4

High Security 14,878 4

Replenishment 21,000 14

Basic Rights 6,000 17 48,458

440,602Surplus of available water assets over water liabilities and future commitments expected to be settled within 12 months of the reporting date. (SWA)

(i) 5,954

Notes: (a) The statistical long term annual minimal inflow sequence to storages. (b) This is an estimate of the annual impact of the net effect rainfall and evaporation on the storages. (c) This is the volume of water set aside to account for the losses encountered in the delivery of the water liabilities and future commitments. (d) This is an allowance for loss set for those periods outside general irrigation releases when essential requirements are required to be supplied. (e) The Gwydir catchment puts aside sufficient amount water asset to meet the essential requirements for two years. This figure represents the essential requirement in year two being made up of Towns, high security, stock and domestic, minimum storage releases, basic rights and estimated loss to deliver them. (f) Sum of the daily end of system flow targets. (g) This is the minimum storage release to be made annually. (h) Indicative Allocation represents a starting allocation 100% for Towns, Domestic and Stock and High Security Licences. (i) Represents uncommitted resources available to be allocated to general security, ECA and corresponding delivery losses.



Note 1 - Surface water storage

This is the actual volume of water stored in the individual surface water storages at the date of reporting. The volumes provided represent the total volume of water in the storage, including dead

storage which is the volume of water which can’t be accessed under normal operating conditions e.g. volume below low level outlet. It is assumed that the dead storage can be accessed if required via alternative access methods e.g. syphons.

Data type

Derived from measured data

Policy

Not applicable

Data accuracy

A – Estimated in the range +/- 10%

Providing agency

NSW Office of Water

Data source

NSW Office of Water – HYDSTRA

Methodology

Storage volumes are calculated by processing a gauged storage elevation through a rating table that

converts it to a volume. The following table provides a breakdown of the storage capacities and dead storages while the plots provide the 2010-11 daily storage volumes and percentages.

Capacity and dead storage summary table

Name Capacity (ML) Dead storage (ML)

Copeton Dam 1,361,720 18,490

Daily volumes for Copeton Dam, 1 July 2010 to 30 June 2011

Headwater Storage Volumes

0

100000

200000

300000

400000

500000

600000

700000

800000

900000

1/07

/10

15/0

7/10

29/0

7/10

12/0

8/10

26/0

8/10

9/09

/10

23/0

9/10

7/10

/10

21/1

0/10

4/11

/10

18/1

1/10

2/12

/10

16/1

2/10

30/1

2/10

13/0

1/11

27/0

1/11

10/0

2/11

24/0

2/11

10/0

3/11

24/0

3/11

7/04

/11

21/0

4/11

5/05

/11

19/0

5/11

2/06

/11

16/0

6/11

30/0

6/11

Stor

age

Vol

ume

(ML)

Copeton Volume



Daily percent storage full for Copeton Dam, 1 July 2010 to 30 June 2011

Headwater Storarge Percentages(above dead storage)

0%

10%

20%

30%

40%

50%

60%1/

07/1

0

15/0

7/10

29/0

7/10

12/0

8/10

26/0

8/10

9/09

/10

23/0

9/10

7/10

/10

21/1

0/10

4/11

/10

18/1

1/10

2/12

/10

16/1

2/10

30/1

2/10

13/0

1/11

27/0

1/11

10/0

2/11

24/0

2/11

10/0

3/11

24/0

3/11

7/04

/11

21/0

4/11

5/05

/11

19/0

5/11

2/06

/11

16/0

6/11

30/0

6/11

Stor

age

Perc

enta

ge (%

)Copeton Percent Full



Note 2 - River channel storage

The volume of water stored in the river channel on the day of reporting.

Policy

Not applicable

Data type


Data accuracy

B – Estimated in the range +/- 25%

Providing agency

NSW Office of Water

Data sources

NSW Office of Water: HYDSTRA, CAIRO

Methodology

For each river section S(n):

V = Q x T

The river channel storage will be equal to the sum of all river section volumes.

River channel storage = S(n) V

Summary of calculation components

Symbol Variable Data Source Unit

Q Average flow in the river section. Calculated by averaging the daily flows at the upstream and downstream river gauges.

HYDSTRA ML/d

V Volume in each river section. Calculated ML

T Average travel time for a parcel of water to travel through the river section.

CAIRO days

Assumptions and approximations:

• Travel times are estimated based on average river flows used in the CAIRO System.

• Daily flow change between gauging sites assumed to be linear.



Additional Information

Breakdown of river volume estimate on 30 June 2011

UPSTREAM DOWNSTREAM

Site Flow (ML/d) Site Flow (ML/d)

Average Flow

(ML/D)

Travel Time

(days)

Volume(ML)

Gwydir River Copeton 41 Gravesend 122 82 4 326Gravesend 122 U/S Tareelaroi 122 122 1 122D/S Tareelaroi 189 U/S Boolaroo 151 170 0.33 56D/S Boolaroo 151 Yarraman 159 155 0.33 51Yarraman 159 U/S Tyreel 221 190 0.33 63D/S Tyreel 136 Brageen 115 126 1 126Brageen 115 Allambi 121 118 1 118Allambi 121 Millewa 96 109 1 109Mehi River Offtake 91 U/S 108 100 2 199D/S Combadello 108 Gundare 1 55 3 164Gundare 1 Ballin Bora 0 1 2 1Ballin Bora 0 Bronte 0 0 2 0Bronte 0 Collarenebri 141 71 2 141Moomin River Offtake 0 Glendello 8 4 1 4Glendello 8 Clarendon 0 19 2 38Clarendon 19 Alma 49 34 2 68Alma 49 Iffley 75 62 2 124Carole Creek D/S Regulator 0 Midkin 3 2 1 2Midkin 3 Garah 7 5 1 5Garah 7 Weemalah 29 18 3 54Weemalah 29 Galloway 86 58 2 115 Total 1,884



Note 3 - Groundwater storage

This is the volume of ‘accounted’ storage asset in the groundwater aquifer for the Lower Gwydir Alluvium Groundwater Management Unit using groundwater accounting Method B (see Note 10 for

further information on groundwater methodologies).

Data type

Estimate

Policy

Not applicable

Data accuracy

A1 – Nil inaccuracy +/- 0%

Providing agency

NSW Office of Water

Data source

NSW Office of Water – Hydrogeology

Methodology

Accounting under the ED AWAS 1 implies that the groundwater storage volume should be initially determined. As the accounts are a rolling, annual update once an initial storage is defined, annual updates will display the change in storage relative to this starting point. The ED AWAS 1 also indicates

that the volume chosen should represent the ‘extractable portion of the aquifer’. For the purposes of this GPWAR it has been assumed that the opening volume of each aquifer is equivalent to twice the licensed entitlement in the aquifer being the maximum annual extraction allowable.

Additional information

The following table illustrates the annual change in storage asset from the beginning of the accounting

period.

Summary of change to the Lower Gwydir Alluvium Groundwater Management Area asset

Year Lower Gwydir Alluvium (ML)

Change (ML)

30-06-2009 87,000* 30-06-2010 70,261 (16,739) 30-06-2011 70,491 230

Cumulative change (16,509)

* Twice total licensed entitlement 2009-10 (megalitres)

The following graphs illustrate the annual change in groundwater levels from the beginning of the accounting period.



Change In Groundwater Levels in the Lower Gwydir Groundwater Management Area (Upper Aquifer) 2009-10

Change In Groundwater Levels in the Lower Gwydir Groundwater Management Area (Lower Aquifer) 2009-10



Change In Groundwater Levels in the Lower Gwydir Groundwater Management Area (Upper Aquifer) 2010-11

Change In Groundwater Levels in the Lower Gwydir Groundwater Management Area (Lower Aquifer) 2010-11



Note 4 - Allocation accounts

These represent the volume of water that is in the licence allocation accounts at the time of reporting. It is the volume of water that is yet to be extracted from the accounts. The balance in accounts at the

end of the water year, being a net balance for the licence category, represents that water that can be carried forward to the next water year and therefore is dictated by carryover rules. Carryover rules determined for licence categories will dictate whether water can or cannot carryover to the next year,

as well as restrictions on the volume of carryover that is permitted. A negative number indicates that more usage has occurred than has been allocated to the account, and the deficit must be carried over to the next season.

Water that is in accounts at the end of a water year but is not permitted to be carried over is forfeited and has been represented as a decrease in water liability.

Data type


Policy

Water Act 1912

Water Sharing Plan for the Gwydir Regulated River Water Source 2002

Available on the NSW Office of Water website at www.water.nsw.gov.au

Data accuracy


Providing agency

NSW Office of Water

Data source

State Water Corporation/NSW Office of Water – Water Accounting System (joint ownership)

Methodology

This figure is the sum of the remaining volume of water in individual’s allocation accounts at the conclusion of the water year once all transactions and forfeit rules have been applied to the accounts. These balances are at the licence category level and represent the water that can be carried forward

for use in the next year. Below is list of typical transactions that can apply to an allocation account:

• AWD

• Licensed extractions

• Excess water orders for those licence categories where water order debiting applied

• Forfeiture due to: o Carryover rules o Account spillage as a result of AWD o Licence conversions

• Licence conversion

• Trade of allocation water between accounts






The tables on the following page provide a balanced summary of the water allocation accounts for each category of access licence. Below is a description of each of the table components.

Explanatory information for allocation account summary

Heading Description

Share This is the total volume of entitlement in the specific licence category as of the date specified

Opening The volume of water that has been carried forward from previous years allocation account.

AWD The total annual volume of water added to the allocation account as a result of allocation assessments.

In Increase in account water as a result of temporary trade in. Assignments

Out Decrease in account water as a result of temporary trade out.

Accountable Volume of water that is extracted or diverted from the river under controlled river conditions and is accountable against the licence.

Extractions Over Order Debit

Volume of water ordered that exceeded the recorded usage for corresponding periods. In the licence categories where water order debiting applies this water must also be accountable against the licence.

During Year Forfeit

Account water forfeited throughout the year as a result of the accounting rules specified in the water sharing plan. For example the maximum a general security account can hold in the Gwydir is 1.5 times the share component of the licence. Water in excess of this limit must be forfeited.

End of Year Balance Account balance that is available to be taken at the conclusion of the water year.

End of Year Forfeit Account water that is forfeited at the end of the water year as a result of carryover rules that restrict the carry forward volume.

Carry Forward This represents the account water that is permitted to be carried forward into the next water year as determined by the carryover rules.


Allocation account balance summary for the Gwydir Regulated River 2010-11

Gwydir Regulated Account Summary Data 2010/11

Assignments Extractions End of Year Balance

Licence Category

Share 30 July 2011

Opening AWD In Out Accountable

Over OrderDebit

During Year

Forfeit Available Non

Available

ForfeitEnd of Year

Carry Forward

Domestic And Stock 2,506 0 2,506 0 0 1,061 5 0 1,440 0 1,440 0

Domestic And Stock [Domestic] 8 0 8 0 0 0 0 0 8 0 8 0

Domestic And Stock [Stock] 230 0 230 0 0 64 0 0 166 0 166 0

Local Water Utility 3,836 (6) 3,836 0 0 2,084 0 0 1,746 0 1,746 0

Regulated River (General Security) 509,665 11,025 422,242 31,943 24,582 97,153 626 297 341,935 617 0 342,552

Regulated River (High Security) 14,818 (11) 14,818 495 7,856 7,347 1 10 89 0 89 0

Regulated River (High Security) [Research]

60 0 60 0 0 0 0 0 60 0 60 0

Supplementary Water 177,347 0 177,347 27,596 27,596 137,440 0 0 39,907 0 39,907 0



Note 5 - Storage inflow

Storage inflow refers to the volume of water flowing into the major headwater storage of Copeton Dam.

Policy

Not applicable

Data type


Data accuracy


Providing agency

NSW Office of Water

Data sources

NSW Office of Water: HYDSTRA, Integrated Quantity and Quality Model (IQQM)

Methodology

In most of the major storages in NSW there is no direct measurement of inflows. However, it is

possible to calculate inflows by using a mass balance approach (based on balancing the change in storage volume) where inflow is the only unknown. This is referred to a backcalculation of inflows.

The backcalculation figures were derived using a one day time step with the inflow calculated

according to the equation below. The daily inflows are then summed to provide an annual inflow figure.

I = ΔS + O + Se + ((E – R)* Kp* A)

Components for backcalculation of inflow

Symbol Variable Unit

I Inflow ML/day

ΔS Change in storage volume ML

O Outflow ML/day

Se Seepage ML/day

R Rainfall mm/day

E Evaporation mm/day

Kp Pan evaporation factor

A Surface area - derived from height to surface areas lookup curve ha

Assumptions and approximations:

• Monthly storage pan evaporation factors were applied.

• Seepage was assumed to be zero.




Daily inflows to Copeton Dam, 1 July 2010 to 30 June 2011

Copeton Dam Daily Inflow

0

5000

10000

15000

20000

25000

30000

35000

1/07

/10

15/0

7/10

29/0

7/10

12/0

8/10

26/0

8/10

9/09

/10

23/0

9/10

7/10

/10

21/1

0/10

4/11

/10

18/1

1/10

2/12

/10

16/1

2/10

30/1

2/10

13/0

1/11

27/0

1/11

10/0

2/11

24/0

2/11

10/0

3/11

24/0

3/11

7/04

/11

21/0

4/11

5/05

/11

19/0

5/11

2/06

/11

16/0

6/11

30/0

6/11

Inflo

w (

ML/

d)



Note 6 - Storage evaporation and storage rainfall

This refers to the volume of water effective on Copeton Dam that is either lost as a result of evaporation, or gained as a result of rainfall.

Data type


Policy

Not applicable

Data accuracy

B – Estimated in the range +/- 25%

Providing agency

NSW Office of Water

Data source

NSW Office of Water – IQQM backcalculation, HYDSTRA

Methodology

While the backcalculation methodology requires the effect of evaporation and rainfall on the storage to

be calculated, it is currently output as a net evaporation figure. The ED AWAS 1 specifies that off-setting should be avoided and as such, a further calculation was required to split the net evaporation figure to rainfall and evaporation. This is achieved by first, outputting daily time-series of storage

surface area from the backcalculation (which uses a height to area lookup curve as defined in HYDSTRA). Daily rainfall and evaporation data is then applied to the area time-series to achieve a volume in megalitres which is then aggregated to an annual figure. The rainfall and evaporation data

utilised is equivalent to the data used in the storage inflow backcalculation, with the same pan factor applied to the evaporation data.

Rainfall: Volume (ML) = Rainfall (mm) x Area (m2) x 10-6

Evaporation: Volume (ML) = Pan Evaporation (mm) x Pan Factor x Area (m2) x 10-6

Pan factors applied to Copeton Dam evaporation data

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

0.86 0.92 0.97 1.08 1.56 1.74 1.55 0.92 0.53 0.55 0.63 0.81



Note 7 - River evaporation and river rainfall

This refers to the volume of water effective on the accounted river reach that is either lost as a result of evaporation, or gained as a result of rainfall.

Data type


Policy

Not applicable

Data accuracy

C – Estimated in the range +/- 50%

Providing agency

NSW Office of Water

Data source

NSW Office of Water: HYDSTRA, ArcGIS

QLD Department of Natural Resources: SILO

Methodology

The volume applied for evaporation and rainfall on the regulated river is achieved by first calculating a daily time-series of river area. This is achieved by breaking the river up into reaches and utilising the

cross sections recorded at river gauging locations to determine the average width of the river with a given daily flow. River length is then determined between two gauging locations using ArcGIS and as such an area for each reach can be defined.

Area (m2) = Average W (m) x L (m)

Where W is the daily width determined from the gauging cross sections and L is the length as determined through ArcGIS analysis.

With daily area determined, various climate stations are then selected based on their proximity to each river reach. Rainfall and evaporation data is then extracted from SILO and applied to the area time-series to achieve a volume in megalitres which is then aggregated to an annual figure.

Rainfall: Volume (ML) = Rainfall (mm) x Area (m2) x 10-6

Evaporation: Volume (ML) = ET0 (mm) x Kc x Area (m2) x 10-6

Where = ET0 = reference evapotranspiration from SILO and Kc = crop factor for open water (1.05)



Note 8 - Tributary inflow

The inflow into the regulated river that occurs downstream of Copeton Dam that is measured at known gauging stations.

Policy

Not applicable

Data type

Measured data

Data accuracy


Providing agency

NSW Office of Water

Data sources

NSW Office of Water: HYDSTRA

Methodology

The flows are obtained by measuring river heights at gauging stations along the river, and then

passing these heights through a rating table that converts them to a daily flow volume.


The total gauged inflow for 2010-11 is the sum of the inflows for the gauged tributaries defined in the table below.

Summary of gauged inflow, 1 July 2010 to 30 June 2011

Station Gauged catchment area

(km2) Volume (ML)

418025 Halls Creek at Bingara 156 2,300

418015 Horton River at Rider 1,970 241,111

418017 Myall Creek at Molroy 842 48,822

418032 Tycannah Creek at Horseshoe 866 14,469

416054 Gil Gil Creek at Boolataroo N/A 6,187

Total inflow 312,889



Gauged Inflow – Halls Creek at Bingara, 1 July 2010 to 30 June 2011

Gwydir Daily Inflow at Halls Creek at Bingara

0

50

100

150

200

250

300

350

400

1/07

/10

15/0

7/10

29/0

7/10

12/0

8/10

26/0

8/10

9/09

/10

23/0

9/10

7/10

/10

21/1

0/10

4/11

/10

18/1

1/10

2/12

/10

16/1

2/10

30/1

2/10

13/0

1/11

27/0

1/11

10/0

2/11

24/0

2/11

10/0

3/11

24/0

3/11

7/04

/11

21/0

4/11

5/05

/11

19/0

5/11

2/06

/11

16/0

6/11

30/0

6/11

Inflo

w (M

L/da

y)

Gauged Inflow – Horton River at Rider, 1 July 2010 to 30 June 2011

Gwydir Daily Inflow at Horton River at Rider

0

5000

10000

15000

20000

25000

30000

1/07

/10

15/0

7/10

29/0

7/10

12/0

8/10

26/0

8/10

9/09

/10

23/0

9/10

7/10

/10

21/1

0/10

4/11

/10

18/1

1/10

2/12

/10

16/1

2/10

30/1

2/10

13/0

1/11

27/0

1/11

10/0

2/11

24/0

2/11

10/0

3/11

24/0

3/11

7/04

/11

21/0

4/11

5/05

/11

19/0

5/11

2/06

/11

16/0

6/11

30/0

6/11

Inflo

w (M

L/da

y)

Gauged Inflow – Myall Creek at Molroy, 1 July 2010 to 30 June 2011

Gywdir Daily Inflow at Myall Creek at Molroy

0

500

1000

1500

2000

2500

3000

3500

4000

1/07

/10

15/0

7/10

29/0

7/10

12/0

8/10

26/0

8/10

9/09

/10

23/0

9/10

7/10

/10

21/1

0/10

4/11

/10

18/1

1/10

2/12

/10

16/1

2/10

30/1

2/10

13/0

1/11

27/0

1/11

10/0

2/11

24/0

2/11

10/0

3/11

24/0

3/11

7/04

/11

21/0

4/11

5/05

/11

19/0

5/11

2/06

/11

16/0

6/11

30/0

6/11

Inflo

w (M

L/da

y)



Gauged Inflow – Tycannah Creek at Horseshoe Lagoon, 1 July 2010 to 30 June 2011

Gwydir Daily Inflow at Tycannah Creek

0

500

1000

1500

2000

2500

3000

1/07

/10

15/0

7/10

29/0

7/10

12/0

8/10

26/0

8/10

9/09

/10

23/0

9/10

7/10

/10

21/1

0/10

4/11

/10

18/1

1/10

2/12

/10

16/1

2/10

30/1

2/10

13/0

1/11

27/0

1/11

10/0

2/11

24/0

2/11

10/0

3/11

24/0

3/11

7/04

/11

21/0

4/11

5/05

/11

19/0

5/11

2/06

/11

16/0

6/11

30/0

6/11

Inflo

w (M

L/da

y)

Gauged Inflow – Gil Gil Creek at Boolataroo, 1 July 2010 to 30 June 2011

Gywdir Daily Inflow at Gil Gil Creek at Boolatooroo

0

100

200

300

400

500

600

700

800

900

1/07

/10

15/0

7/10

29/0

7/10

12/0

8/10

26/0

8/10

9/09

/10

23/0

9/10

7/10

/10

21/1

0/10

4/11

/10

18/1

1/10

2/12

/10

16/1

2/10

30/1

2/10

13/0

1/11

27/0

1/11

10/0

2/11

24/0

2/11

10/0

3/11

24/0

3/11

7/04

/11

21/0

4/11

5/05

/11

19/0

5/11

2/06

/11

16/0

6/11

30/0

6/11

Inflo

w (M

L/da

y)



Note 9 - Ungauged runoff estimate

The inflow into the river that occurs downstream of the headwater storages that is not measured.

Policy

Not applicable

Data type

Estimated

Data accuracy


Providing agency

NSW Office of Water

Data sources

NSW Office of Water, HYDSTRA

Methodology

The method used to estimate the ungauged component assumes the ungauged sub-catchment characteristics and rainfall extent similar to that of nearby gauged sub-catchments. Gauged tributary inflows are used as a basis for proportioning on area and rainfall distribution across the catchment as

defined by the following steps:

• derive the ratio of gauged to ungauged area by summing gauged area and calculating the

ungauged area as the total catchment area less the gauged catchment area

• derive a ratio of annual rainfall volume of the gauged catchment area compared to that of the

ungauged area (RF)

• the ungauged inflow is then calculated using the following equation: Ungauged Inflow (ML/yr) = Ungauged Area (Ha)/Gauged Area (Ha) x RF x Gauged Inflow (ML/yr)

Assumptions

RF was assumed to be 1, while area ratios were only considered for the part of the catchment upstream of the Gwydir River at Pallamallawa.



Note 10 - Groundwater

This note is applicable to all parameters presented in the groundwater balance of the accounts.

Data type

Modelled, estimated

Policy

Not applicable

Data accuracy

D – Estimated in the range +/- 100%

Providing agency

NSW Office of Water

Data sources

NSW Office of Water: HYDSTRA, GDS

QLD Department of Natural Resources: SILO

Commonwealth Bureau of Meteorology: AWAP

NSW Department of Environment and Heritage: Soil Profiles

Methodology

In order to provide a greater coverage of groundwater data in the water accounts NSW Office of Water have developed a range of methodologies to derive budget estimates. Detailed information of theses

methods (Method A, Method B and Method C) are available in the report “General Purpose Water Accounting Reports: Groundwater Methodologies (Ali 2011), which can be downloaded from www.water.nsw.gov.au

In summary, when producing GPWARs for each groundwater management unit a method is generally selected according to the following decision tree.

Groundwater methodology decision tree

For this GPWAR however, it was only possible to implement method B for the Lower Gwydir Groundwater Management Area. In future GPWARs this will be extended to include Method C for the




remaining extent (Method A is excluded as there is currently not a model suitable for accounting purposes).

The following map gives the methodologies adopted for the different areas of the Gwydir catchment.

Groundwater methodologies utilised for 2010-11

METHOD B Summary (Water table fluctuation)

Description

The water table fluctuation method is based on the premise that the rises in groundwater levels in unconfined aquifers are due to recharge water arriving at the water table and links the change in groundwater storage (∆S) with the resulting water table fluctuations (∆h):

hSS y Δ=Δ (1)

Where:

Sy is specific yield of the aquifer

Δh is the change in groundwater levels

The employed methodology is based on applying the water table fluctuation method in conjunction with the groundwater water budget method to jointly estimate specific yield and natural recharge in an unconfined aquifer with significant seasonal water table fluctuations. The water budget method

focuses on the various components contributing to groundwater flow and groundwater storage changes (detailed in the figure below) and can be written as:

SQQPGETQQRFR bfoffriveron Δ++++=+++ (2)

Where:

R is direct recharge from rainfall




RF is irrigation return flow

Qon and Qoff are lateral groundwater flow onto and off the groundwater system

Qriver is river seepage recharge

ET is evapotranspiration

PG is abstraction of groundwater by pumping

Qbf is baseflow (groundwater discharge to streams or springs)

∆S is change in groundwater storage.

Schematic diagram showing the flow components of the groundwater budget

PGR rain

QonQoff

∆S

ET RF

Qbf Qriver

Combining equation (1) with equation (2), we obtain:

hSQQPGETQQRFR ybfoffriveron Δ++++=+++ (3)

By applying equation (3) separately to the dry season, during which R=0, and the wet season, we

obtain two equations where the specific yield and natural recharge are the only two unknown parameters:

dryy

drybf

dryoff

drydrydryriver

dryon

dry hSQQPGETQQRF Δ++++=++ (4)

wety

wetbf

wetoff

wetwetwetriver

weton

wet hSQQPGETQQRFR Δ++++=+++ (5)

With the exception of the specific yield and natural recharge, all other seasonal parameters in equation (4) and (5) are either known or can somehow be estimated.

Using equations (4) and (5), the average specific yield and the natural recharge of the aquifer can be

estimated as follows:

( ) ( )dry

dryoff

drybf

drydrydryon

dryriver

dry

y h

QQETPGQQRFS

Δ+++−++

= (6)

)()( wetriver

weton

wetwety

wetbf

wetoff

wetwet QQRFhSQQPGETR ++−Δ++++= (7)


Account outputs

• Lateral flow

• Recharge (rainfall and river)

• Aquifer inflow from river

• Aquifer outflow to river

• Evapotranspiration – from top layer of aquifer

• Usage is required for the simulation and is output in the results. The original input was obtained from the Water Accounting System

Additional Information for Method B

Lower Gwydir Groundwater Management Area (Upper Aquifer) Budget Diagram, 2010-11

Qleak= 20.77

PG=12.35R rain= 26.29

Qon= 0Qoff= 0

∆S1= 0.05

ET = 16.93RF =11.70

Qbf =41.90Qriver= 54.01

Lower Gwydir Groundwater Management Area (Lower Aquifer) Budget Diagram, 2010-11

PG = 20.58

Qon2 Qoff2

∆S2 = 0.18

0.00.0

Qleak= 20.77

∆S1= 0.18




Components

Qriver = River Loss (River Recharge) Qbf = River Gain (Baseflow) ET = Evapotranspiration Qon = Lateral Flow In Qleak = Inter Layer Leakage

∆S = Storage Change Qoff = Lateral Flow Out PG = Groundwater Usage by Pumping RF = Irrigation Return Flow Rrain = Rain Recharge


Note 11 - Dam releases, river inflow from dam releases

The volume of water released from Copeton Dam. In the accounting process this release is represented as both a decrease in asset (of the dams) and an equal increase in asset (of the river).

Policy

Not applicable

Data type

Measured data

Data accuracy


Providing agency

NSW Office of Water

Data sources

NSW Office of Water: HYDSTRA

Methodology

The flows are obtained by measuring river heights at a gauging station downstream of the dam wall, and then passing these heights through a rating table that converts them to a daily flow volume. The

releases have been represented in the Statement of Changes in Water Assets and Water Liabilities as both a decrease in water asset (water leaving the dam) and an equal volume of increase in water asset (water released increasing the volume of the river). It would have been also possible to account

this as a transfer in asset whereby the volumes would not appear in the statements.


Summary of releases, 1 July 2010 to 30 June 2011 (ML)

Headwater Storage Daily Releases

0

500

1000

1500

2000

2500

3000

3500

4000

4500

1/07

/10

15/0

7/10

29/0

7/10

12/0

8/10

26/0

8/10

9/09

/10

23/0

9/10

7/10

/10

21/1

0/10

4/11

/10

18/1

1/10

2/12

/10

16/1

2/10

30/1

2/10

13/0

1/11

27/0

1/11

10/0

2/11

24/0

2/11

10/0

3/11

24/0

3/11

7/04

/11

21/0

4/11

5/05

/11

19/0

5/11

2/06

/11

16/0

6/11

30/0

6/11

Stor

age

Rele

ase

(ML/

d)

Copeton Releases



Note 12 – Flow to Wetlands

This refers to the total volume of water delivered to the wetlands via the Lower Gwydir and Gingham Watercourse. The actual flows diverted from the river to the wetlands need to be adjusted to account for that portion that was diverted to deliver replenishment flows. This flow will include that water

delivered both under the minimum flow rule and as a result of supplementary flow sharing.

Data type


Policy

Not applicable

Data accuracy


Providing agency

NSW Office of Water

Data source

NSW Office of Water – HYDSTRA, State Water Compliance Report (Internal document)

Methodology

Summation of flows at the assessment gauging site/s measuring the volume of water that passes into the wetlands. These flows will then need to be reduced by the volume of water that has been provided for replenishment flows. The following table summarises the gauges that are being used to assess the

total flow diverted to deliver water to the wetlands and for replenishments and provides a summary of the actual water delivered to the wetlands.


Detailed breakdown of gauges used and assessment of flows to the wetlands

Station Station name Gauged volume (ML)

Total gaugedflow(ML)

Less replenishment

flow (ML)

Delivered flow to

wetlands (ML)

418066 Gwydir River at Millewa 63,304

418074 Gingham Channel at Teralba 92,808 156,112 4,478 151,634



Daily plot of flow to wetlands, 01 July 2010 to 30 June 2011

Flow to Wetlands

0

1000

2000

3000

4000

5000

6000

7000

1/07

/10

15/0

7/10

29/0

7/10

12/0

8/10

26/0

8/10

9/09

/10

23/0

9/10

7/10

/10

21/1

0/10

4/11

/10

18/1

1/10

2/12

/10

16/1

2/10

30/1

2/10

13/0

1/11

27/0

1/11

10/0

2/11

24/0

2/11

10/0

3/11

24/0

3/11

7/04

/11

21/0

4/11

5/05

/11

19/0

5/11

2/06

/11

16/0

6/11

30/0

6/11

Flow

(ML/

day)

Gwydir at Millewa 418066 Gingham Channel at Teralba 418074



Note 13 – End of System Flows

This refers to flow that leaves the entity and does not return to the entity.

Data type


Policy

Not applicable

Data accuracy


Providing agency

NSW Office of Water

Data source

NSW Office of Water – HYDSTRA, State Water Compliance Report (Internal document)

Methodology

Summation of flows at gauging site/s measuring the volume of water that passes the end of system gauges. The following table summarises the gauges used to assess the end of system flow for the

Gwydir reporting entity.


Detailed breakdown of end of system flows

Station Station name Volume (ML)

418055 Mehi River near Collarenebri 35,110 416052 Gil Gil Creek at Galloway 15,857 Total 50,967

Daily plot of end of system flow, 01 July 2010 to 30 June 2011

Gwydir Daily Flow at End of System

0

50

100

150

200

250

300

1/07

/10

15/0

7/10

29/0

7/10

12/0

8/10

26/0

8/10

9/09

/10

23/0

9/10

7/10

/10

21/1

0/10

4/11

/10

18/1

1/10

2/12

/10

16/1

2/10

30/1

2/10

13/0

1/11

27/0

1/11

10/0

2/11

24/0

2/11

10/0

3/11

24/0

3/11

7/04

/11

21/0

4/11

5/05

/11

19/0

5/11

2/06

/11

16/0

6/11

30/0

6/11

Flow

(ML/

day)

Mehi Near Collerenbri 418055 Gil Gil Creek at Galloway 416052



Note 14 – Replenishment Flows

This refers to water that is set aside as part of the essential requirements for the provision of flows along effluent streams to supply water for households, town use and stock. The effluent streams and annual limits to be delivered are detailed in the water sharing plan.

Data type


Policy

Not applicable

Data accuracy


Providing agency

NSW Office of Water

Data source

NSW Office of Water – State Water Compliance Report (Internal document)

Methodology

Diversions measured via a combination of authorised diversion works (Thalaba Creek and Ballin Bora

Creek) and flows at gauging sites (Gingham Watercourse, Gwydir downstream and Mallowa Creek) measuring the volume of water. The following table summarises the assessed replenishment flows for the 2010-11 water year.


Replenishment Flow Summary

Area of replenishment Annual

Replenishment Limit (ML)

Delivered 2010-11

(ML)

Gingham Watercourse 6,000 1,528

Gwydir downstream of Water Source 4,000 2,950

Mallowa Creek 6,000 3,130

Thalaba Creek 4,000 3,582

Ballin Bora Creek 1,000 324

Total 21,000 11,514



Note 15 – Licenced extractions

This refers to the actual volume of water either pumped or diverted from the river or aquifer by licensed users. It is broken up by licence category and in some circumstances by water sharing plan rules e.g. for uncontrolled flow.

Data type

Measured data

Policy

Not applicable

Data accuracy


Providing agency

NSW Office of Water

Data source

State Water/NSW Office of Water – Water Accounting System (Joint ownership of system).

NSW Office of Water – Water Ordering and Usage database

Methodology

The extraction and diversion data is collected by either on-farm meters that measure extraction or gauges on diversion works. Meter readings are collected for individual licence holders at intervals during the year and converted via a calibration factor to a volume of water extracted. Water diverted

from the river is measured by recording the height at either the gauge or weir with the volume diverted being derived by passing these heights through a rating table. However, with multiple categories of access licences being extracted through the same pumps additional information and methodologies

are required to separate use under the various licence categories. Below is a description of these:

• Based on periods of announcement – during periods of supplementary water announcements

extractions can be debited against the Supplementary Water Licences.

• Extractions based on water orders – users place orders for water against an access licence

and extractions are debited against accounts in proportion to the orders placed.

• Licence Category Apportionment – if no water orders are available water extracted is apportioned against categories of access licence in order of priority as set out in the table

below. The prioritising is based on the nature and rules around each of the licence categories.

The following table provides the order in which extractions are apportioned to access licence categories. In the table following licensed extractions are apportioned in order of priority starting at priority 1. This is a generic list where not all categories will necessarily appear in this GPWAR. There

are also various sub categories of licence associated with some of the categories.



Licence category apportionment table

Priority Surface water Groundwater

1 Supplementary Domestic and Stock

2 Uncontrolled Flow Supplementary

3 Domestic and Stock Aquifer

4 Regulated River High Security Local Water Utility

5 Regulated River General Security Major Water Utility

6 Conveyance

7 Local Water Utility

8 Major Water Utility



Note 16 – Supplementary Water

This is the volume of water extracted or diverted under supplementary access licences during announced periods of supplementary water. Supplementary flow events are announced periodically during the season when high flow events occur with the period of extraction and volume of water to be

extracted determined based on the rules as set out in the water sharing plans. It is important to note that supplementary access licences differ from other categories of access licence in that the volume of water in the account refers to an annual upper limit for extractions and its provision is totally reliant on

the occurrence of high flow events.

Data type

Measured data

Policy


Part 8 Limits to the availability of water Division 2 - Available water determinations - Clause 39 Available water determinations for supplementary water access licences

Part 9 Rules for managing access licences Division 3 - Extraction conditions - Clause 48 Taking of water under supplementary water access licences

Refer to applicable Water Sharing Plan on NSW Office of Water website at www.water.nsw.gov.au

Data accuracy

Estimated in the range +/- 10%

Providing agency

NSW Office of Water

Data source


Methodology

Supplementary water extraction and diversion data is collected by either on farm meters that measure

extraction or gauges on diversion works. Meter readings are collected for individual licence holders at intervals during the year and converted via a calibration factor to a volume of water extracted. Water diverted from the river is measured by recording the height at either the gauge or weir with the volume

diverted being derived by passing these heights through a rating table. However, with supplementary water being extracted through the same pumps as those extracting water under other categories of access licences additional information is required to separate out supplementary extraction. Basically

licence holders provide notification of their intention to pump prior to pumping or diverting water during the declared supplementary event and provide meter readings both at the commencement and conclusion of pumping. This enables the supplementary flow extraction to be assessed independent of

other categories of access licences.

The total volume permitted to be extracted from any supplementary event is restricted to 50% of the event volume and is calculated by summing the individual extractions and diversions that occurred

during declared periods of supplementary flow for the water year.


http://www.water.nsw.gov.au/Water-Management/Water-sharing/default.aspx



Gwydir supplementary announcements by river section 2010-11 Stream River section Start date End date Gwydir River Copeton to Bingara 2 August 2010 6 August 2010

Gwydir River Copeton to Bingara 13 August 2010 17 August 2010

Gwydir River Copeton to Bingara 24 August 2010 27 August 2010

Gwydir River Copeton to Bingara 6 September 2010 8 September 2010

Gwydir River Copeton to Bingara 11 September 2010 13 September 2010

Gwydir River Copeton to Bingara 16 October 2010 19 October 2010

Gwydir River Bingara to Gravesend 2 August 2010 6 August 2010



Gwydir River Bingara to Gravesend 6 September 2010 8 September 2010

Gwydir River Bingara to Gravesend 11 September 2010 13 September 2010

Gwydir River Bingara to Gravesend 16 October 2010 19 October 2010

Gwydir River Gravesend to Pallamallawa 2 August 2010 6 August 2010



Gwydir River Gravesend to Pallamallawa 6 September 2010 8 September 2010

Gwydir River Gravesend to Pallamallawa 11 September 2010 13 September 2010

Gwydir River Gravesend to Pallamallawa 16 October 2010 19 October 2010

Gwydir River Gravesend to Pallamallawa 20 November 2010 22 November 2010

Gwydir River Gravesend to Pallamallawa 11 December 2010 14 December 2010

Gwydir River Pallamallawa to Tareelaroi 2 August 2010 6 August 2010



Gwydir River Pallamallawa to Tareelaroi 6 September 2010 8 September 2010

Gwydir River Pallamallawa to Tareelaroi 11 September 2010 13 September 2010

Gwydir River Pallamallawa to Tareelaroi 16 October 2010 19 October 2010

Gwydir River Pallamallawa to Tareelaroi 20 November 2010 22 November 2010

Gwydir River Pallamallawa to Tareelaroi 11 December 2010 14 December 2010

Gwydir River Tareelaroi to Boolooroo 2 August 2010 6 August 2010



Gwydir River Tareelaroi to Boolooroo 6 September 2010 8 September 2010

Gwydir River Tareelaroi to Boolooroo 11 September 2010 13 September 2010

Gwydir River Tareelaroi to Boolooroo 16 October 2010 19 October 2010

Gwydir River Tareelaroi to Boolooroo 19 October 2010 19 October 2010

Gwydir River Tareelaroi to Boolooroo 20 November 2010 22 November 2010

Gwydir River Boolooroo to Yarraman 2 August 2010 6 August 2010

Gwydir River Boolooroo to Yarraman 24 August 2010 27 August 2010

Gwydir River Boolooroo to Yarraman 1 September 2010 2 September 2010



Gwydir River Yarraman to Tyreel Weir 2 August 2010 6 August 2010

Gwydir River Yarraman to Tyreel Weir 24 August 2010 27 August 2010

Gwydir River Yarraman to Tyreel Weir 1 September 2010 2 September 2010



Gwydir River Yarraman to Tyreel Weir 16 October 2010 19 October 2010

Gwydir River Yarraman to Tyreel Weir 20 October 2010 20 October 2010

Gwydir River Tyreel/Reg to Morcott 12 August 2010 23 August 2010

Gwydir River Tyreel/Reg to Morcott 24 August 2010 31 August 2010



Stream River section Start date End date Gwydir River Tyreel/Reg to Morcott 7 September 2010 8 September 2010

Gwydir River Tyreel/Reg to Morcott 11 September 2010 12 September 2010



Gwydir River Tyreel/Reg to Morcott 17 October 2010 19 October 2010

Gwydir River Tyreel/Reg to Morcott 4 December 2010 11 December 2010

Gwydir River Morcott to Brageen 12 August 2010 23 August 2010

Gwydir River Morcott to Brageen 24 August 2010 31 August 2010

Gwydir River Morcott to Brageen 7 September 2010 8 September 2010




Gwydir River Morcott to Brageen 3 October 2010 3 October 2010

Gwydir River Morcott to Brageen 17 October 2010 19 October 2010

Gwydir River Morcott to Brageen 5 December 2010 11 December 2010

Gwydir River Brageen to Allambi 12 August 2010 23 August 2010

Gwydir River Brageen to Allambi 24 August 2010 31 August 2010

Gwydir River Brageen to Allambi 7 September 2010 8 September 2010




Gwydir River Brageen to Allambi 3 October 2010 3 October 2010

Gwydir River Brageen to Allambi 17 October 2010 20 October 2010

Gwydir River Brageen to Allambi 5 December 2010 11 December 2010

Gwydir River Allambi to Millewa 12 August 2010 23 August 2010

Gwydir River Allambi to Millewa 7 September 2010 8 September 2010




Gwydir River Allambi to Millewa 3 October 2010 3 October 2010

Gwydir River Allambi to Millewa 17 October 2010 19 October 2010

Gwydir River Allambi to Millewa 5 December 2010 11 December 2010

Gwydir River Millewa to Wandoona 12 August 2010 23 August 2010

Gwydir River Millewa to Wandoona 7 September 2010 8 September 2010




Gwydir River Millewa to Wandoona 3 October 2010 3 October 2010

Gwydir River Millewa to Wandoona 17 October 2010 20 October 2010

Mehi River Tareelaroi to Moree 2 August 2010 6 August 2010

Mehi River Tareelaroi to Moree 24 August 2010 31 August 2010

Mehi River Tareelaroi to Moree 11 September 2010 14 September 2010

Mehi River Tareelaroi to Moree 17 October 2010 19 October 2010

Mehi River Tareelaroi to Moree 25 October 2010 25 October 2010

Mehi River Tareelaroi to Moree 14 November 2010 18 November 2010

Mehi River Tareelaroi to Moree 12 December 2010 17 December 2010

Mehi River Moree to Combadello 2 August 2010 6 August 2010

Mehi River Moree to Combadello 24 August 2010 31 August 2010

Mehi River Moree to Combadello 11 September 2010 14 September 2010

Mehi River Moree to Combadello 17 October 2010 19 October 2010

Mehi River Moree to Combadello 25 October 2010 25 October 2010

Mehi River Moree to Combadello 14 November 2010 18 November 2010



Stream River section Start date End date Mehi River Moree to Combadello 12 December 2010 17 December 2010

Mehi River Combadello to Yamba 12 August 2010 20 August 2010

Mehi River Combadello to Yamba 24 August 2010 31 August 2010

Mehi River Combadello to Yamba 1 September 2010 2 September 2010

Mehi River Combadello to Yamba 12 September 2010 15 September 2010

Mehi River Combadello to Yamba 18 October 2010 20 October 2010



Mehi River Combadello to Yamba 22 November 2010 25 November 2010

Mehi River Combadello to Yamba 8 December 2010 10 December 2010

Mehi River Combadello to Yamba 13 December 2010 16 December 2010

Mehi River Combadello to Yamba 8 January 2011 11 January 2011

Mehi River Yamba to Gundare 12 August 2010 20 August 2010

Mehi River Yamba to Gundare 24 August 2010 31 August 2010

Mehi River Yamba to Gundare 1 September 2010 2 September 2010

Mehi River Yamba to Gundare 14 September 2010 16 September 2010

Mehi River Yamba to Gundare 18 October 2010 20 October 2010



Mehi River Yamba to Gundare 23 November 2010 25 November 2010

Mehi River Yamba to Gundare 8 December 2010 12 December 2010

Mehi River Yamba to Gundare 13 December 2010 16 December 2010

Mehi River Yamba to Gundare 8 January 2011 11 January 2011

Mehi River Gundare to Kurrabooma 12 August 2010 20 August 2010

Mehi River Gundare to Kurrabooma 24 August 2010 31 August 2010

Mehi River Gundare to Kurrabooma 1 September 2010 2 September 2010



Mehi River Gundare to Kurrabooma 19 October 2010 22 October 2010

Mehi River Gundare to Kurrabooma 22 October 2010 22 October 2010

Mehi River Gundare to Kurrabooma 24 November 2010 28 November 2010

Mehi River Gundare to Kurrabooma 8 December 2010 12 December 2010

Mehi River Gundare to Kurrabooma 13 December 2010 16 December 2010

Mehi River Kurrabooma to Ballinboora 12 August 2010 20 August 2010

Mehi River Kurrabooma to Ballinboora 24 August 2010 31 August 2010

Mehi River Kurrabooma to Ballinboora 1 September 2010 2 September 2010



Mehi River Kurrabooma to Ballinboora 20 October 2010 24 October 2010

Mehi River Kurrabooma to Ballinboora 24 October 2010 24 October 2010

Mehi River Kurrabooma to Ballinboora 25 November 2010 28 November 2010

Mehi River Kurrabooma to Ballinboora 8 December 2010 13 December 2010

Mehi River Kurrabooma to Ballinboora 13 December 2010 16 December 2010

Mehi River Ballinboora to Bronte 6 August 2010 12 August 2010

Mehi River Ballinboora to Bronte 1 September 2010 6 September 2010



Mehi River Ballinboora to Bronte 3 October 2010 3 October 2010




Mehi River Ballinboora to Bronte 2 November 2010 3 November 2010



Stream River section Start date End date Mehi River Ballinboora to Bronte 25 November 2010 29 November 2010

Mehi River Bronte to Myambla 3 August 2010 20 August 2010

Mehi River Bronte to Myambla 15 September 2010 19 September 2010

Mehi River Bronte to Myambla 20 September 2010 21 September 2010

Mehi River Bronte to Myambla 3 October 2010 3 October 2010



Mehi River Bronte to Myambla 2 November 2010 3 November 2010

Mehi River Bronte to Myambla 26 November 2010 30 November 2010

Mehi River Myambla to Collarenebri 3 August 2010 20 August 2010

Mehi River Myambla to Collarenebri 15 September 2010 19 September 2010

Mehi River Myambla to Collarenebri 20 September 2010 21 September 2010

Moomin Creek Combadello to Romani 24 August 2010 31 August 2010

Moomin Creek Combadello to Romani 1 September 2010 2 September 2010

Moomin Creek Combadello to Romani 11 September 2010 13 September 2010

Moomin Creek Combadello to Romani 18 October 2010 21 October 2010



Moomin Creek Combadello to Romani 19 November 2010 21 November 2010

Moomin Creek Combadello to Romani 8 December 2010 13 December 2010

Moomin Creek Combadello to Romani 13 December 2010 16 December 2010

Moomin Creek Combadello to Romani 15 January 2011 16 January 2011

Moomin Creek Romani to Glendello 24 August 2010 31 August 2010

Moomin Creek Romani to Glendello 1 September 2010 2 September 2010

Moomin Creek Romani to Glendello 11 September 2010 13 September 2010

Moomin Creek Romani to Glendello 19 October 2010 22 October 2010



Moomin Creek Romani to Glendello 19 November 2010 21 November 2010

Moomin Creek Romani to Glendello 8 December 2010 13 December 2010

Moomin Creek Romani to Glendello 13 December 2010 16 December 2010

Moomin Creek Romani to Glendello 15 January 2011 16 January 2011

Moomin Creek Glendello to Chesney 12 August 2010 20 August 2010

Moomin Creek Glendello to Chesney 24 August 2010 31 August 2010

Moomin Creek Glendello to Chesney 8 September 2010 10 September 2010

Moomin Creek Glendello to Chesney 11 September 2010 14 September 2010

Moomin Creek Glendello to Chesney 19 October 2010 23 October 2010

Moomin Creek Glendello to Chesney 23 October 2010 23 October 2010

Moomin Creek Glendello to Chesney 21 November 2010 25 November 2010

Moomin Creek Glendello to Chesney 8 December 2010 13 December 2010

Moomin Creek Glendello to Chesney 14 December 2010 17 December 2010

Moomin Creek Glendello to Chesney 15 January 2011 17 January 2011

Moomin Creek Chesney to Clarendon 12 August 2010 20 August 2010

Moomin Creek Chesney to Clarendon 24 August 2010 31 August 2010

Moomin Creek Chesney to Clarendon 8 September 2010 10 September 2010

Moomin Creek Chesney to Clarendon 11 September 2010 14 September 2010

Moomin Creek Chesney to Clarendon 3 October 2010 3 October 2010



Moomin Creek Chesney to Clarendon 23 November 2010 30 November 2010

Moomin Creek Chesney to Clarendon 8 December 2010 13 December 2010

Moomin Creek Chesney to Clarendon 14 December 2010 18 December 2010



Stream River section Start date End date Moomin Creek Chesney to Clarendon 15 January 2011 17 January 2011

Moomin Creek Clarendon to Wirrillah 6 August 2010 12 August 2010

Moomin Creek Clarendon to Wirrillah 24 August 2010 31 August 2010

Moomin Creek Clarendon to Wirrillah 10 September 2010 13 September 2010

Moomin Creek Clarendon to Wirrillah 14 September 2010 17 September 2010

Moomin Creek Clarendon to Wirrillah 25 October 2010 25 October 2010

Moomin Creek Clarendon to Wirrillah 25 November 2010 30 November 2010

Moomin Creek Clarendon to Wirrillah 8 December 2010 13 December 2010

Moomin Creek Clarendon to Wirrillah 15 December 2010 18 December 2010

Moomin Creek Wirrillah to Alma 6 August 2010 12 August 2010

Moomin Creek Wirrillah to Alma 25 August 2010 31 August 2010

Moomin Creek Wirrillah to Alma 10 September 2010 13 September 2010

Moomin Creek Wirrillah to Alma 16 September 2010 18 September 2010

Moomin Creek Wirrillah to Alma 25 October 2010 25 October 2010

Moomin Creek Wirrillah to Alma 25 November 2010 30 November 2010

Moomin Creek Wirrillah to Alma 8 December 2010 15 December 2010

Moomin Creek Wirrillah to Alma 15 December 2010 18 December 2010

Moomin Creek Alma to Iffley 18 August 2010 30 August 2010

Moomin Creek Alma to Iffley 12 September 2010 16 September 2010

Moomin Creek Alma to Iffley 16 September 2010 20 September 2010

Moomin Creek Alma to Iffley 21 October 2010 27 October 2010

Moomin Creek Alma to Iffley 28 October 2010 31 October 2010

Moomin Creek Alma to Iffley 25 November 2010 30 November 2010

Moomin Creek Alma to Iffley 3 December 2010 6 December 2010



Moomin Creek Iffley to Oreal 12 August 2010 16 August 2010

Moomin Creek Iffley to Oreal 7 September 2010 10 September 2010

Moomin Creek Iffley to Oreal 25 November 2010 30 November 2010

Moomin Creek Iffley to Oreal 12 December 2010 17 December 2010

Moomin Creek Iffley to Oreal 6 January 2011 8 January 2011



Carole Creek Boolooroo to Midkin 2 August 2010 20 August 2010

Carole Creek Boolooroo to Midkin 24 August 2010 31 August 2010

Carole Creek Boolooroo to Midkin 7 September 2010 9 September 2010

Carole Creek Boolooroo to Midkin 12 September 2010 13 September 2010

Carole Creek Boolooroo to Midkin 17 October 2010 20 October 2010

Carole Creek Boolooroo to Midkin 25 October 2010 25 October 2010

Carole Creek Boolooroo to Midkin 20 November 2010 22 November 2010

Carole Creek Boolooroo to Midkin 4 December 2010 7 December 2010

Carole Creek Boolooroo to Midkin 12 December 2010 14 December 2010

Carole Creek Boolooroo to Midkin 8 January 2011 9 January 2011

Carole Creek Midkin to Lagoon 12 August 2010 20 August 2010

Carole Creek Midkin to Lagoon 24 August 2010 31 August 2010

Carole Creek Midkin to Lagoon 12 September 2010 16 September 2010

Carole Creek Midkin to Lagoon 17 October 2010 21 October 2010

Carole Creek Midkin to Lagoon 25 October 2010 25 October 2010

Carole Creek Midkin to Lagoon 20 November 2010 22 November 2010

Carole Creek Midkin to Lagoon 4 December 2010 7 December 2010

Carole Creek Midkin to Lagoon 12 December 2010 14 December 2010

Carole Creek Midkin to Lagoon 8 January 2011 9 January 2011



Stream River section Start date End date Carole Creek Lagoon to Garah Bridge 12 August 2010 20 August 2010

Carole Creek Lagoon to Garah Bridge 24 August 2010 31 August 2010

Carole Creek Lagoon to Garah Bridge 12 September 2010 16 September 2010

Carole Creek Lagoon to Garah Bridge 2 October 2010 2 October 2010



Carole Creek Lagoon to Garah Bridge 21 November 2010 25 November 2010

Carole Creek Lagoon to Garah Bridge 4 December 2010 7 December 2010

Carole Creek Lagoon to Garah Bridge 13 December 2010 15 December 2010

Carole Creek Lagoon to Garah Bridge 9 January 2011 10 January 2011

Carole Creek Garah Bridge to Gil Gil Junction 24 August 2010 31 August 2010

Carole Creek Garah Bridge to Gil Gil Junction 7 September 2010 11 September 2010




Carole Creek Garah Bridge to Gil Gil Junction 2 October 2010 2 October 2010




Carole Creek Garah Bridge to Gil Gil Junction 22 November 2010 26 November 2010

Carole Creek Garah Bridge to Gil Gil Junction 6 December 2010 11 December 2010

Carole Creek Garah Bridge to Gil Gil Junction 20 December 2010 23 December 2010

Carole Creek Garah Bridge to Gil Gil Junction 11 January 2011 13 January 2011

Carole Creek Garah Bridge to Gil Gil Junction 18 June 2011 25 June 2011

Gil Gil Creek Gil Gil Junction to Rio Grand 24 September 2010 26 September 2010

Gil Gil Creek Gil Gil Junction to Rio Grand 27 September 2010 28 September 2010

Gil Gil Creek Gil Gil Junction to Rio Grand 2 October 2010 2 October 2010



Gil Gil Creek Gil Gil Junction to Rio Grand 15 December 2010 18 December 2010

Gil Gil Creek Gil Gil Junction to Rio Grand 20 December 2010 23 December 2010

Gil Gil Creek Gil Gil Junction to Rio Grand 16 January 2011 20 January 2011

Gil Gil Creek Gil Gil Junction to Rio Grand 18 June 2011 25 June 2011

Gil Gil Creek Rio Grande to Cleveland 26 September 2010 27 September 2010

Gil Gil Creek Rio Grande to Cleveland 28 September 2010 30 September 2010

Gil Gil Creek Rio Grande to Cleveland 2 October 2010 2 October 2010



Gil Gil Creek Rio Grande to Cleveland 16 December 2010 20 December 2010

Gil Gil Creek Rio Grande to Cleveland 20 December 2010 23 December 2010

Gil Gil Creek Rio Grande to Cleveland 17 January 2011 20 January 2011

Gil Gil Creek Rio Grande to Cleveland 20 January 2011 24 January 2011

Gil Gil Creek Rio Grande to Cleveland 18 June 2011 25 June 2011

Gwydir Pool Tyreel Weir to Gwydir Pool 2 August 2010 6 August 2010

Gwydir Pool Tyreel Weir to Gwydir Pool 24 August 2010 27 August 2010

Gwydir Pool Tyreel Weir to Gwydir Pool 1 September 2010 2 September 2010



Gwydir Pool Tyreel Weir to Gwydir Pool 16 October 2010 19 October 2010

Tyreel Anabranch Tyreel Anabranch 16 October 2010 19 October 2010

Unnamed Watercourse Tyreel to Morcott 3 October 2010 3 October 2010

Unnamed Watercourse Tyreel to Morcott 17 October 2010 19 October 2010



Note 17 - Basic rights extractions

This is the non-licensed right to extract water to meet basic requirements for household purposes (non-commercial uses in and around the house and garden) and for watering of stock. It is available for anyone who has access to river frontage on their property.

This water cannot be used for irrigating crops or garden produce that will be sold or bartered, for washing down machinery sheds or for intensive livestock operations.

In times of limited supply, there may be restrictions on taking water for domestic and stock use.

Data type

Estimated

Policy


• Part 4 Basic Landholder Rights

o Clause 18 Domestic and stock rights Available on the NSW Office of Water website at www.water.nsw.gov.au

Data accuracy


Providing agency

NSW Office of Water

Data source


Methodology

The estimation of domestic and stock rights uses a series of estimates for water usage, stocking rates, population and property shape based on local knowledge to calculate riparian (stock and domestic) requirements in megalitres per year. The annual extraction for Domestic and Stock rights in the water

accounts is assumed to be the estimated figure stated in the Water Sharing Plan for the Gwydir Regulated River Water Source (6,000 ML)




Note 18 - Available Water Determination (AWD) (Allocation Announcement)

This is the process by which the regulated surface water asset available for use within the regulated

system is determined and shared. It determines the volume of water that is to be added to an individuals licence allocation account. Announcements of allocations are made on a seasonal basis - usually corresponding with the financial year and are updated on a regular basis or following

significant inflow events. Under the Water Management Act 2000 the announcements are termed available water determinations, while under the Water Act 1912 this process is known as an allocation announcement.

Data type

Derived from measured data.

Policy

Water Act 1912.

Water Management Act 2000 (NSW).

• Chapter 3 – Part 2 Access Licences.

o Clause 59 – Available Water Determinations.

Water Sharing Plan for the Gwydir Regulated River Water Source.

• Part 8 – Limits to the availability of water

o Division 2 – Available Water Determinations.

Available on the NSW Office of Water website at www.water.nsw.gov.au

Data accuracy


Providing agency

NSW Office of Water.

Data source


Available Water Determination Register - NSW Office of Water website at www.water.nsw.gov.au

Methodology

In the Gwydir Regulated Water Source AWDs are calculated based on a concept of continuous accounting which assesses the resource (water) contained in the headwaters storage, periodically updating projections and distributing the regulated (stored) resource available. All projections are for

two (2) years from the date of the assessment. It is important to note that under continuous accounting the AWD’s are based on the actual volume of water in storage at the time of the resource assessment and does not account for sequences of future inflows.

Each assessment process firstly involves the assessment of the effective storage, being the available storage volume after storage losses are accounted for. This is to account for the fact that storage losses cannot be controlled by a management rule and, therefore, must be provided for first. Following

this existing commitments are taken into account and then any uncommitted water is first committed to essential supplies, then added to the delivery loss account to targeting a volume equivalent to a maximum of 30% of the deliverable general security and then to the ECA account. Any remaining






uncommitted water is then shared in proportion to the amount of entitlement in the remaining resource categories.

The essential supplies mentioned above consist of items such as stock and domestic requirements,

Local Water Utilities (e.g. town water supplies, industrial use), High Security (permanent plantings e.g. orchards, vineyards), end of system flow requirement resulting from the system operation and minimum storage releases.

The volume of water distributed to licence categories is expressed as either a volume per share or as a percentage of share component depending on the category of licence. The following table details each licence category and how it is announced.

Access Licence category announcement type

Licence category Announcement type

General Security Volume per Share

High Security Volume per Share

Domestic and Stock* Percent of Share Component

Local Water Utility Percent of Share Component

Note: Domestic and Stock consists of three sub categories: Domestic and Stock, Domestic and Stock (Domestic) and Domestic and Stock (Stock). High Security consists of two sub categories: High Security and High Security (Research).

It should be noted that the AWD for supplementary licence accounts is a separate process and is not

dependent on water asset available. It is made once at the start of the year and unless there is a management change due to the growth in use strategy it is maintained at the maximum value prescribed in the plan generally 1 ML per share (equivalent to 100% of entitlement). Therefore, it is not

considered to create a liability on the system and is only considered in terms of an extraction that reduces the water asset.


The following pages contain the allocation summary reports for 2010-11. Below is a table containing report notes to help interpret the report.

Allocation Summary Report Notes

Opening Remaining allocation account balances at the conclusion of the previous season that is allowed to be carried forward to this season.

Individual Announcement Actual announcement made to each licence category

Share Component (Entitlement) Sum of the licensed volume of water within the licence category on the announcement date.

Announced Volume Volume of water credited to accounts within a licence category as a result of the announcement made.

Cumulative Volume Cumulative total of the announced volumes for the water year and licence category.

Percent of Share Component (Entitlement)

This is the announced volume expressed as a percentage of the entitlement applicable on the particular date.

Balance Made Available Sum of water available in allocation accounts that has been made available to be taken during the season.

Non Available Balance Water allocated that is not accessible at this point in time.


GWYDIR REGULATED RIVER WATER SOURCE

01 July 2010 - 30 June 2011

Date Individual

Announcement Entitlement

Allocation Volume

Cumulative Volume

% of Entitlement

Cumulative %

Balance Available

Non Available

Total Balance

Available Balance

Total Domestic and Stock Start 2,506 0 0 0 0.0% 0.0%

1-Jul-10 AWD 100.0 % 2,506 2,506 2,506 100.0% 100.0% 2,506 0 2,506 100.0% 100.0% Domestic and Stock (Domestic) Start 8 0 0 0 0.0% 0.0%

1-Jul-10 AWD 100.0 % 8 8 8 100.0% 100.0% 8 0 8 100.0% 100.0% Domestic and Stock (Stock) Start 230 0 0 0 0.0% 0.0%

1-Jul-10 AWD 100.0 % 230 230 230 100.0% 100.0% 230 0 230 100.0% 100.0% Local Water Utility Start 3,836 (6) 0 (6) -0.2% -0.2%

1-Jul-10 AWD 100.0 % 3,836 3,836 3,836 100.0% 100.0% 3,830 0 3,830 99.8% 99.8% Regulated River (General Security) Start 509,665 11,015 10 11,025 2.2% 2.2%

2-Sep-10 AWD 0.0346 ML per Share 509,665 17,633 17,633 3.5% 3.5% 28,647 11 28,658 5.6% 5.6% 15-Sep-10 AWD 0.0748 ML per Share 509,665 38,120 55,752 7.5% 10.9% 66,764 13 66,777 13.1% 13.1% 30-Sep-10 AWD 0.0549 ML per Share 509,665 27,980 83,732 5.5% 16.4% 94,741 16 94,757 18.6% 18.6% 21-Oct-10 AWD 0.0981 ML per Share 509,665 49,994 133,726 9.8% 26.2% 144,732 19 144,751 28.4% 28.4% 1-Nov-10 AWD 0.0245 ML per Share 509,665 12,484 146,210 2.4% 28.7% 157,215 20 157,235 30.8% 30.8% 6-Dec-10 AWD 0.2629 ML per Share 509,665 133,968 280,178 26.3% 55.0% 291,175 28 291,203 57.1% 57.1% 5-Jan-11 AWD 0.1246 ML per Share 509,665 63,494 343,673 12.5% 67.4% 354,653 45 354,698 69.6% 69.6% 4-Feb-11 AWD 0.131 ML per Share 509,665 66,746 410,419 13.1% 80.5% 421,003 441 421,444 82.6% 82.7% 7-Mar-11 AWD 0.0232 ML per Share 509,665 11,823 422,242 2.3% 82.8% 432,650 617 433,267 84.9% 85.0%

Regulated River (High Security) Start 14,818 (11) 0 (11) -0.1% -0.1%

1-Jul-10 AWD 1.0 ML per Share 14,818 14,818 14,818 100.0% 100.0% 14,807 0 14,807 99.9% 99.9% Regulated River (High Security)(Research) Start 60 0 0 0 0.0% 0.0%

1-Jul-10 AWD 1.0 ML per Share 60 60 60 100.0% 100.0% 60 0 60 100.0% 100.0% Supplementary Water Start 177,347 0 0 0 0.0% 0.0%

1-Jul-10 AWD 1.0 ML per Share 177,347 177,347 177,347 100.0% 100.0% 177,339 0 177,339 100.0% 100.0%



Note 19 - Internal trading

This represents the temporary trading (allocation assignments) of water between allocation accounts within the regulated Gwydir River.

Data type

Administration

Policy

Water Sharing Plan for the Gwydir Regulated River Water Source 2002.

• Part 10 Access licence dealing rules

o Clause 50 rules relating to constraints within a water source

Available on the NSW Office of Water Website at www.water.nsw.gov.au

Water Act 1912

Data accuracy


Providing agency

NSW Office of Water

Data source


Water Ordering and Usage database

Methodology

Trading is permitted between certain categories of access licences and between certain water sources. This is detailed in the water sharing plan or stipulated under the licence holder’s conditions.

The net internal trade for each licence category is zero for a water year. As such, trades occur as both a water liability decrease (sellers of water) and a water liability increase (buyers of water).


The table below shows the internal trading figures between licence categories. All figures represent a volume in megalitres.

Trade To Gwydir

Licence Category General Security High Security Supplementary

Total

General Security 24,087 495 0 24,582

High Security 7,856 7,856

Trad

e Fr

om

Gw

ydir

Supplementary 27,596 27,596

Total 31,943 495 27,596 60,034




Note 20 - Unaccounted difference

In theory if all the processes of a water balance could be accurately accounted for the unaccounted difference would be zero. In reality due to the large uncertainties in many of the volumes presented in the accounts, the various sources from which the data has been obtained and the fact that not all

processes of the water cycle have been accounted, the statements are not balanced at the end of the accounting process. In order to balance the accounts a final balancing entry is required, and this has been termed the unaccounted difference. As technology progresses and accuracy improves in the

account estimates, it is anticipated that relatively, this figure should reduce in future accounts.

Data type

Not applicable

Policy

Not applicable

Data accuracy

D – Estimated in the range +/- 100%

Providing agency

Not applicable

Data source

Not applicable

Methodology

For surface water the unaccounted difference is equal to the amount required to obtain the correct volume in river at the end of the reporting period, after all the known physical inflows and outflows have been accounted. The double-entry accounting process attempted to represent the physical

movement of water by creating a river asset and adding or subtracting the volumes of the relevant inflows and outflows. The opening and closing balance of the river volume was estimated according to Note 2.

For groundwater the area covered by Method B, which was the only method utilised in this GPWAR (see Note 10), the full balanced output from the groundwater modelling was used and as such has no unaccounted difference (the balance is closed).

Surface Water Unaccounted difference

UVSW = Rs – Rc + RI - Ro

Where:

UVSW = Unaccounted difference for Surface Water

Rs = Opening river volume estimate

Rc = Closing river volume estimate

Ro = Physical outflows from the river (e.g. extractions)

RI = Physical inflows to the river (e.g. runoff, return flows, dam releases)



Note 21 – Held Environmental Water

This represents that environmental water that is held as part of a licensed volumetric entitlement. These licences are held within the same licence categories as all other water access licences hence are subject to the same operating rules. Therefore they are subject to the following key rules:

• Available Water Determinations (AWD) for their share of the entitlement to be added to accounts.

• Carryover rules hence the forfeiting of unused water that cannot be carried over.

• Provide water orders prior to use.

These licences are used to provide environmental benefit and outcomes to the catchment by either providing water to, or supplementing water requirements of, a specific environmental events or

incidents.

Data type

Measured

Policy

Water Management Act 2000

• Dealings with access licences (Division 4)

o 71G Assignment of water allocations between access licences

Water Sharing Plan for the Gwydir Regulated River Water Source 2002.


Data accuracy


Providing agency

NSW Office of Water

Data source

State Water/NSW Office of Water – Water Accounting System (Joint ownership of System).


Methodology

The water held for the environment represents a volume of water in corresponding allocation accounts. This allocation account represents the sum of the remaining volume of held environmental

water at the conclusion of the water year once all transactions and forfeit rules have been applied to the accounts. These environmental balances are at the licence category level and represent the water that can be carried forward for use in the next year. Below is list of typical transactions that can apply

to an environmental allocation account:

• AWD (including pro rata of AWD for new licences)

• Licensed extractions

• Forfeiture due to:

o Carryover rules

o Account spillage as a result of AWD

o Licence conversions






o Excess orders (where water order debiting is in place)

• Licence conversion

• Trade of allocation water between accounts

In addition the trade and purchase of environmental water is tracked to capture the movement of

environmental entitlement both in number of entitlements, and volume.


The table on the following page provides a summary of held environmental water for 2010-11.

Explanatory information for Environmental Account Summary

Heading Description

No. Lic. This is the number of environmental licences held.

Share This is the total volume of entitlement in the specific licence category.

Opening The volume of water that has been carried forward from previous years allocation account.

AWD The total annual volume of water added to the allocation account as a result of allocation assessments.

In Increase in account water as a result of Temporary Trade in. Assignments

Out Decrease in account water as a result of Temporary Trade out.

Extractions Volume of water that is extracted or diverted from the river under controlled river conditions and is accountable against the licence.

Available Balance Account balance that is available to be taken at the conclusion of the water year.

Not Available Balance Account balance that is currently not available for use (e.g. restricted due to drought conditions or annual use limit restrictions)

End of Year Forfeit Account water that is forfeited at the end of the water year as a result of carryover rules that restrict the carry forward volume.

Carry Forward This represents the account water that is permitted to be carried forward into the next water year as determined by the carryover rules.


Environmental Regulated Account Summary 2010-11 (ML)

Assignments Extractions End of Year Balance Licence Category

Share 30 June

2011 CO In

AWD

New Licences

In Out Accountable

During Year

Forfeit Available Non

Available

ForfeitEnd of Year

Carry Forward

Regulated river (general security) 106,617 1,324 87,797 0 10,000 10,570 14,657 0 73,895 0 0 73,895 Regulated river (high security) 375 0 0 385 0 375 0 10 0 0 0 0 Supplementary water 19,540 0 19,540 0 0 0 3,056 0 16,484.2 0 16,484 0

Note: 70 ML of the regulated river (general security) water trade out was extracted by a non environmental licence and delivered as environmental water.

Change in held environmental water 2010-11 (ML)

As at 30 June 2010 As at 30 July 2011 Differences Licence Category

No. Licences

Share (ML) No.

Licences Share (ML)

No. Licences

Share (ML)

Regulated river (general security) 9 105,612 9 106,617 0 1,005 Regulated river (high security) 1 0 3 375 2 375 Supplementary water 5 19,540 5 19,540 0 0

Gywdir environmental trading summary table 2010-11 (ML)

Trade To

Environmental Non Environmental

Gwydir Gwydir

Gwydir Environmental Trade Summary Report

2010-11

General Security General Security Total

General Security 10,000 570 10,570

Envi

ronm

enta

l

Gw

ydir

High Security 375 375

Trad

e Fr

om

Total 10,000 945 10,945



Note 22 – Environmental Contingency Allowance

The is a provision of planned environmental water introduced under the water sharing plan, with the aim of enhancing environmental benefits, in particular the Gwydir wetlands and its associated ecosystems.

The Environmental Contingency Allowance (ECA) is controlled by the NSW Office of Environment and Heritage (OEH). The ECA account is increased whenever there is a general security available water determination and shall be credited with a volume equal to the lesser of:

(i) 45,000 megalitres multiplied by the number of megalitres per unit share specified in that available water determination, and

(ii) 90,000 megalitres minus the volume currently in the account

The water may be called upon for use by OEH for a range of environmental purposes including support of native bird breeding, inundation of the Gwydir wetlands during extended dry regimes and support of native fish habitat and breeding cycles.

Data type

Measured

Policy

Water Sharing Plan for the Gwydir Regulated River Source 2002.

• Part 3 Environmental Water Provisions

• Clause 15 Planned Environmental Water


Data accuracy


Providing agency

NSW Office of Water

Data source

State Water/NSW Office of Water – Water Accounting System (Joint ownership of System).


Methodology

An account has been set up in the water accounting system to track the balance of the ECA. The

account is increased when General Security Available Water Determinations are made and decreased through usage. The account is also bound by the limits specified in the water sharing plan (i.e. 90,000 ML). Similar to other allocation accounts the ECA has been presented as a liability in this GPWAR,

representing a commitment to supply that amount of water as called upon.


Summary of ECA account balance

Water Year Water Credited Usage Balance 2009-10 0 0 17,305 2010-11 37,287 5,000 49,592





Gwydir catchment

Assurance Statement

An Assurance Statement is required under the ED AWAS 1 for a general purpose water account

which states that the accounts were prepared in accordance with the ED AWAS 1. It is a requirement that this be provided by an appropriately qualified assurance provider independent of the water reporter and it management and governing body.

An assurance framework has yet to be provided under the ED AWAS 1 and in lieu of it the NSW Office of Water will not be providing an Assurance Statement for the 2010-11 water account. It should be noted that at the time of publication WASB is in the process of developing an assurance standard for

which more details can be seen on the WASB website.




References Ali A. (2011) General Purpose Water Accounting Reports: Groundwater methodologies, NSW Office of

Water, Sydney

BOM 2010, Pilot National Water Account, Bureau of Meteorology

OEH 2011 Marsh club-rush sets seed. In: Water for the Enviroment News, June 2011. NSW Office of Environment and Heritage, Sydney.

WASB 2010, Exposure Draft of Australian Water Accounting Standard 1 Preparation and Presentation of General Purpose Water Accounting Reports (ED AWAS 1), Bureau of Meteorology

general purpose water accounting report 2010–2011: gwydir ... · in line with this recommendation...

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