General Purpose Water Accounting Report 2013-2014€¦ · Physical Flows Mass Balance Diagram...

General Purpose Water Accounting Report 2013-2014

Lower Darling catchment

Publisher: NSW Department of Primary Industries, Office of Water

Title: General Purpose Water Accounting Report 2013-2014– Lower Darling catchment

First published: December 2014

ISBN: 978-1-74256-703-7

More information

[email protected]

www.water.nsw.gov.au

This report may be cited as: Burrell M., Moss P., Petrovic J., Ali A., (2014) General Purpose Water Accounting Report 2013-2014: Lower Darling catchment, NSW Department of Primary Industries, Sydney

www.water.nsw.gov.au

Cover image: Darling River upstream of Burtundy

Jobtrack number 13355

© State of New South Wales through the Department of Trade and Inv estment, Regional Inf rastructure and Serv ices 2014. You may copy , distribute and otherwise f reely deal with this publication f or any purpose, prov ided that y ou attribute the NSW Department of Primary Industries as the owner.

Disclaimer: The inf ormation contained in this publication is based on knowledge and understanding at the time of writing (December 2014). Howev er, because of adv ances in knowledge, users are reminded of the need to ensure that inf ormation upon which they rely is up to date and to check currency of the inf ormation with the appropriate of f icer of the Department of Primary Industries or the user’s independent adv iser..

mailto:[email protected]

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

General Purpose Water Accounting Report 2013-2014 – Low er Darling catchment

i NSW Office of Water, December 2014

Table of Contents Introduction ........................................................................................................................................ 8 Contextual Statement .......................................................................................................................... 9

Accounting Extent ........................................................................................................................... 9

Surface Water ............................................................................................................................. 9 Groundwater ............................................................................................................................... 9 Rainfall.......................................................................................................................................11

Storage inflows and volume.........................................................................................................13 Significant water accounting policies................................................................................................18 Quantification of data......................................................................................................................18

Lower Darling Catchment ...................................................................................................................19 Physical Flows Mass Balance Diagram (2013-2014).........................................................................19

Lower Darling catchment ....................................................................................................................20

Water Assets and Water Liabilities ..................................................................................................20 Lower Darling catchment ....................................................................................................................21

Changes in Water Assets and Water Liabilities.................................................................................21

Lower Darling catchment ....................................................................................................................22 Reconciliation and future prospect descriptions ................................................................................24 Note 1 – Allocation accounts ...........................................................................................................26

Note 2 – Available Water Determination (AWD)................................................................................29 Note 3 – Allocation account usage...................................................................................................32 Note 4 – Temporary Trading/Allocation assignments ........................................................................34

Note 5 – Held environmental water ..................................................................................................36 Note 6 – Environmental provisions ..................................................................................................39 Note 7 – Surface water storage – Combined Menindee System ........................................................41

Note 8 – River channel storage .......................................................................................................44 Note 9 – Storage inflow – Combined Menindee System ....................................................................45 Note 10 – Storage evaporation and storage rainfall ..........................................................................46

Note 11 – River evaporation and river rainfall ...................................................................................47 Note 12 – Talyawalka Creek Inflow..................................................................................................48 Note 13 – Dam releases, river inflow from dam releases ...................................................................49

Note 14 – End of system flow..........................................................................................................50 Note 15 – Extractions from River .....................................................................................................51 Note 16 – Basic rights.....................................................................................................................52

Note 17 – Unregulated Effluent to Great Darling Anabranch ..............................................................53 Note 18 – Unaccounted difference...................................................................................................54 Note 19 – Adjusting entry ................................................................................................................55

References ........................................................................................................................................56


ii NSW Office of Water, December 2014

Tables Table 1: 2013-14 monthly rainfall and historic monthly data at Menindee and Pooncarie...................11 Table 2: Water account data accuracy estimates key .....................................................................18 Table 3: Explanatory information for allocation account summary ....................................................27 Table 4: Allocation account balance summary for the Lower Darling Regulated River 2013-14..........28 Table 5: Priority of access licence categories .................................................................................29 Table 6: Explanatory information for Allocation Announcement Table ..............................................30 Table 7: Allocation Announcements for Lower Darling Regulated River Water Source 2013-14.........31 Table 8: Licence category metered usage apportionment table .......................................................33 Table 9: Account usage summary 2013-14 ....................................................................................33 Table 10: Lower Darling Regulated River temporary trade summary 2013-14 ....................................35 Table 11: Explanatory information for held environmental allocation account summary .......................37 Table 12: Lower Darling environmental account summary 2013-14 ...................................................38 Table 13: Change in held environmental water 2013-14 ...................................................................38 Table 14: Summary of ECA account balance (figures in ML).............................................................39 Table 15: Capacity and dead storage summary table .......................................................................41 Table 16: Summary of river storage calculation components .............................................................44 Table 17: Components for backcalculation of inflow .........................................................................45 Table 18: Pan factors utilised for calculation ....................................................................................46 Table 19: Summary of Talyawalka Creek at Railway Bridge inflow 2013-14 .......................................48 Table 20: Summary of releases, 1 July 2013 to 30 June 2014...........................................................49 Table 21: End of System Flow summary table .................................................................................50

Figures Figure 1: Surface water geographical extent of the accounts ............................................................10 Figure 2: Monthly rainfall and 2013-14 median deviations from historical records at Menindee and

Pooncarie .......................................................................................................................11 Figure 3: Darling River catchment 2013-14 total annual rainfall ........................................................12 Figure 4: Darling River catchment average annual rainfall 1961-1990...............................................12

Figure 5: Long-term total flow (ML/year) at Wilcannia against mean and 2013-14 flow .......................13 Figure 6: Inflows at Wilcannia against rainfall 2013-14 .....................................................................13 Figure 7: Menindee combined storage capacity volume and percent full 2013-14 ..............................14

Figure 8: Water Availability (AWD plus carry over)...........................................................................14 Figure 9: Entitlement since the commencement of the Water Sharing Plan (excluding supplementary)

......................................................................................................................................15

Figure 10: Total diversions since commencement of the Water Sharing Plan (excluding supplementary) ......................................................................................................................................15

Figure 11: Net trade in of the Lower Darling (excluding supplementary) ..............................................16

Figure 12: Held environmental water share component in the Lower Darling since the commencement of the water sharing plan .....................................................................................................16

Figure 13: Lake Wetherell storage level and effective full storage capacity 2013-14 ............................42

Figure 14: Lake Pamamaroo storage level and effective full storage capacity 2013-14 ........................42


iii NSW Office of Water, December 2014

Figure 15: Lake Menindee storage level and effective full storage capacity 2013-14 ............................42 Figure 16: Lake Cawndilla storage level and effective full storage capacity 2013-14 ............................43

Figure 17: End of system flow for Darling River 2013-14....................................................................50 Figure 18: Reconciliation of extraction from river to account usage 2013-14........................................51


iv NSW Office of Water, December 2014

Abbreviations Acronym Description

AWAS Austra lian Water Accounting Standard

AWD Avai lable Water Determination

CAIRO Computer Aided Improvements to River Operations

Ck Creek

D/S Downstream

GIS Geographic Information System

GL Gigalitres (1,000,000,000 l i tres)

GPWAR General Purpose Water Accounting Report

IQQM Integrated Quantity and Quality Model

LAS Licencing Administration System

MDBA Murray-Darling Basin Authority

ML Megalitres (1,000,000 l itres)

NSW New South Wales

U/S Upstream

WASB Water Accounting Standards Board


v | NSW Office of Water, December 2014

Glossary Al location The specific volume of water allocated to water allocation accounts in a given season,

defined according to rules established in the relevant water plan.

Al location assignments The transfer of water between l icence holder a llocation accounts as a result of a trade agreement. The assignment becomes part of the receiver’s current year a l location account water.

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

Ava i lable Water Determination (AWD)

The process by which water i s 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 l icence allocation account.

Austra lian 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 i tems in a GPWAR.

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

Bas ic 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 ra infall and contribute to surface water (s treams, 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.

Dead s torage 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.

Effective s torage The tota l volume of storage minus the dead s torage 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.

Enti ty 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.

Envi ronmental water Water a llocated to support environmental outcomes and other public benefits. Envi ronmental water provisions recognise the environmental water requirements and are based on environmental, social and economic considerations, including exis ting user rights.

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

Evapotranspiration The process by which water i s 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 l icensed users for a specific purpose (irrigation, s tock, domestic, towns, etc). The volume is measured at the point of extraction or diversion (river pump, diversion works etc).


vi | NSW Office of Water, December 2014

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 s tatement

General security l icence 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 enti tlements 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.

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

HYDSTRA database A database used by NSW Office of Water to s tore 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 s tate).

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.

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).

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

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

Share component An enti tlement 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 l icence holder is a l located as a result of an available water determination and the amount they can take in any year is based on their share component.

Storage A s tate-owned dam, weir or other s tructure which is used to regulate and manage river flows in the catchment and the water bodies impounded by these s tructures.

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

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

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

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

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

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


vii | NSW Office of Water, December 2014

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 l iabilities Cla ims on the water assets of the water report entity including water that has been a l located 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.


8 | NSW Office of Water, December 2014

Introduction

This document is a General Purpose Water Accounting Report for the regulated surface water component of the Lower Darling River, prepared by the NSW Office of Water under the Australian Water Accounting Standard 1 framework (WASB 2012).

It has been prepared for the reporting period of 1 July 2013 to 30 June 2014 and aims to provide a consolidated and informative summary of the water resource and water management that occurred within the regulated Lower Darling river system for this period.

During 2013-14 management of this water source was implemented according to the Water Sharing Plan for the New South Wales Murray and Lower Darling Regulated Rivers Water Sources 2003.

As Deputy Commissioner of the New South Wales Office of Water I hereby declare:

• The information presented in these accounts is a faithful representation of the management and operation of the Regulated Lower Darling in 2013-14

• All data presented in this report is based on the best available information at the time of publication.

• The NSW Office of Water has to the best of its ability prepared this General Purpose Water Accounting Report for the Lower Darling regulated river water source in accordance with the Australian Water Accounting Standard 1.

Bruce Cooper Deputy Commissioner, Water Resource Assessment and Management New South Wales Office of Water



Contextual Statement The Lower Darling River is located in the semi-arid environment of south-western New South Wales. The ‘Lower Darling’ commonly refers to that portion of the Darling River which is regulated by releases from the Menindee Lakes Scheme, from the township of Menindee to its junction with the Murray River at Wentworth 530 km downstream.

The general topography of the catchment is flat with elevations across most of the floodplain area being less than 100 metres. Land use is dominated by grazing with small areas of cropping carried out in the southern half of the catchment and on some of the region’s lake beds.

Prior to construction of the Menindee Lakes Scheme the Lower Darling River was unregulated, and like the unregulated portion of the catchment above Menindee, it was subject to highly variable flow conditions. With completion of the Scheme in 1960 the flow regime of the river has changed significantly, with reduced monthly flow volumes, long periods of constant low flow and reduced frequency of small to medium sized flow events (Green et al. 1998).

A detailed description of the catchment can be found in the document Water resources and management overview – Lower Darling Catchment which is available from the NSW Office of Water website.

Accounting Extent

Surface Water The accounted river extent is illustrated in Figure 1 and includes the Lower Darling Water Source managed under the Water Sharing Plan for the NSW Murray and Lower Darling Water Sources. It includes the Lower Darling Regulated River System downstream of Menindee Lakes from the township of Menindee downstream to its junction with the Murray River at Wentworth. As the flow data at Wentworth is both limited and backwater affected by flow in the Murray River, the flow site on the Darling River at Burtundy was used as an alternative measure for the end of system flow.

While the Great Darling Anabranch is not included as part of this GPWAR, the flow leaving the defined entity that enters the Anabranch is accounted for in order to achieve a correct mass balance. Licenced usages on the Great Darling Anabranch are also provided in the Lower Darling 2013-14 ‘Physical Flow Diagram’ (Water Accounting Statements section of this GPWAR). The only inflow that is considered to the Lower Darling River is the return flow of Talyawalka Creek.

Groundwater No groundwater information has been included in this GPWAR



Figure 1: Surface water geographical extent of the accounts



Rainfall The Lower Darling experienced drier than median conditions during 2013-14 with the major exception of February 2014 (lower catchment) and April 2014 (upper catchment), where rainfall was well in exceedance of historical median (Figure 2). During these months there was 99.5 mm recorded at Pooncarie (lower catchment) and 77.8 mm at Mungindi (upper catchment).

Overall annual rainfall (July 2013 – June 2014) was approximately 30 per cent below the historical average at Menindee and 10 per cent below at Pooncarie. Monthly rainfall statistics for Menindee and Pooncarie are displayed in Figure 2 and Table 1.

2013-14 annual rainfall distribution across the Lower Darling is displayed in Figure 3, and can be referenced against the mean annual rainfall distribution in Figure 4. Here it can be seen that while 2013-14 rainfall is generally lower than average across the entire catchment, it was particularly low around the Menindee Lakes northward to Wilcannia. Figure 2: Monthly rainfall and 2013-14 median deviations from historical records at Menindee and Pooncarie

Table 1: 2013-14 monthly rainfall and historic monthly data at Menindee and Pooncarie 1 Month Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun Annual Menindee 2013-14 8.6 5.0 5.6 4.2 4.4 12.2 2.0 18.4 12.4 77.8 20.5 5.7 176.8 Historic statistics Mean 18.4 17.7 18.5 22.8 20.7 21.9 24.0 21.7 18.5 16.5 22.6 21.8 244.5 Median 12.8 13.5 13.2 16.6 11.6 10.1 7.8 9.4 7.3 8.6 16.4 16.0 214.8 Lowest 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.3 62.2 Highest 113.5 67.6 79.3 113.2 163.5 197.5 231.7 157.1 165.6 152 107.2 111.7 732.3 Highest Year 1886 1901 1964 1938 1933 1887 1993 1950 1989 1974 1989 1923 1973-1974 Month Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun Annual Pooncarie 2013-14 20.7 18.3 2.6 4.0 3.0 22.1 6.6 99.5 6.8 29.6 27.2 2.5 242.9 Historic statistics Mean 22.6 22.5 21.4 26.1 20.5 21.7 23.1 23.9 18.3 17.7 25.8 25.8 268.5 Median 19.3 20.0 15.8 18.1 12.0 12.1 10.5 9.7 9.4 10.2 17.6 19.2 244.8 Lowest 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 87.4 Highest 81.6 92.1 101.9 142.4 109.8 200.6 162 193 178.8 157.5 151.6 130.9 763.5 Highest Year 1996 1901 1964 1973 2010 1962 2011 2000 1989 1974 1889 1923 2010-2011

1 Long term statistics are derived from the Bureau of Meteorology – climate data online. The data presented is collected from the stations ‘47019 – Menindee Post Off ice’ and ‘47029 – Pooncarie Mail Agency’. Historic statistics use data from 1876 to 2014 for Menindee and 1883 to 2014 for Pooncarie.



Figure 3: Darling River catchment 2013-14 total annual rainfall

Figure 4: Darling River catchment average annual rainfall 1961-1990



Storage inflows and volume Using river flows on the Darling River at Wilcannia as an indicator of storage inflow and Lower Darling resources, 2013-14 conditions were significantly below average (Figure 5). Total annual flow at this point was 140,657 megalitres compared to the long term average of 1,934,966 megalitres (around 93 per cent below average).

The majority of this volume arrived in two separate events, the first was a continuation of an event from the end of 2012-13, and peaked in August at around 1,000 megalitres per day (Figure 6). The second event, which was slightly higher in peak volumes but smaller in duration, began in April 2014 and peaked at a total daily flow volume of 1,200 megalitres per day. Figure 5: Long-term total flow (ML/year) at Wilcannia 1 against mean and 2013-14 flow

Figure 6: Inflows at Wilcannia against rainfall 2013-14

The combined Menindee Lakes storage volume was at 72 per cent of capacity on 1 July 2013. This volume was generally maintained through to summer, where the storage starts to

1 Total f low at Wilcannia is the sum of the f low at Darling River at Wilcannia Main Canal (425008) and Talyaw alka Creek at Barrier Highw ay (Wilcannia) (425018)



decline with full demand, which includes environmental releases down the Great Darling Anabranch. With demand reducing following the high demand season, the storage remained steady through to 30 June 2014, closing at 22 per of full storage capacity. Further details can be found in Note 7 of this GPWAR. Figure 7: Menindee combined storage capacity volume and percent full 2013-14

All licence categories were granted with an equivalent allocation of 100 per cent on 1 July 2013. In addition, general security licence holders were allowed to carry over 18,210 megalitres from 2012-13, taking the total 2013-14 water availability for that category to 121 per cent (Figure 8). Figure 8: Water Availability (AWD plus carry over)1

High water availability combined with dry conditions resulted in the highest account usage since the commencement of the water sharing plan in 2004-05. There was a 65 per cent increase on 2012-13 usage (which was previously the highest year for usage). The usage also increased due to large volumes of environmental water being released (55,243 megalitres, or 35 per cent of the total 2013-14 Lower Darling usage)

1 The AWD plus carryover for general security licences in excess of 100% is a result of the w ater sharing plan rules w hich allow s for carryover to include the on-farm storage capacities. An individual’s maximum availability is the greater of 100% AWD or carryover plus 50% AWD. For more details refer to w ater sharing plan.



Total account usage for general security and high security licence categories was 188 per cent and 54 per cent of total entitlement respectively (Figure 9 and Figure 10). This excludes a significant net volume of water traded into the Lower Darling in 2013-14. A total of 95,863 megalitres was moved into the catchment with around 30,000 of this being associated with environmental licences (water moved in to supplement an environmental release down the Great Darling Anabranch) Figure 9: Entitlement since the commencement of the Water Sharing Plan (excluding supplementary)1

Figure 10: Total diversions since commencement of the Water Sharing Plan (excluding supplementary)

All supplementary entitlement (250,000 megalitres) in the Lower Darling is held as environmental water. While supplementary licences were granted 100 per cent of entitlement, with the whole of this entitlement being held environmental water the environmental benefits were achieved by allowing any uncontrolled events to flow through the system as opposed to extracting or diverting the flows. As a result no supplementary flow events were declared.

1 Increase in entitlement in 2009-10 due to the granting of an environmental licence equivalent to savings obtained through a channel piping program.



Figure 11: Net trade in of the Lower Darling (excluding supplementary)

-70,000

-20,000

30,000

80,000

130,000

2004-05 2005-06 2006-07 2007-08 2008-09 2009-10 2010-11 2011-12 2012-13 2013-14

Allo

catio

n As

sign

men

ts (M

L)Water AvailabilityAssignments In Assignments Out Net Assignments In

Held environmental water allowed remained relatively constant throughout 2013-14 with some slight increases in additional purchases, sales or issued entitlement.

As at 30 June 2014 there were 48,595 megalitres of general security, 897 megalitres of high security and 250,000 megalitres of supplementary water of held licensed environmental water available for use in the Lower Darling (Figure 12). Figure 12: Held environmental water share component in the Lower Darling since the commencement of the water sharing plan

0

100,000

200,000

300,000

2004-05 2005-06 2006-07 2007-08 2008-09 2009-10 2010-11 2011-12 2012-13 2013-14

Held

Env

ironm

enta

l Sha

res (

ML)

Supplementary General Security High Security

Detailed information of environmental watering in NSW is available from the NSW Office of Environment and Heritage website (www.environment.nsw.gov.au) and the Australian Department of Environment (www.environment.gov.au), while further details on held environmental licence balances and trading is available in Note 5 of this document.

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

http://www.environment.gov.au/



Water Accounting Statements



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).

The ‘Statement of Physical Flows’ has been excluded for this GPWAR as all transactions have been presented in the statements ‘Water Assets and Liabilities’ and ‘Changes in Water Assets and Water Liabilities’.

A ‘Physical Flow Diagram’ that represents the physical movements of water has been included in order to provide a clearer picture of this process.

For a detailed explanation on how to interpret the NSW Office of Water water accounting statements refer to the report Interpreting New South Wales Office of Water General Purpose Water Accounting Reports, available for download on from the NSW Office of Water website.

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 (Table 2). Table 2: Water account data accuracy estimates key

Accuracy Description

A1

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

A +/- 10%

B +/- 25%

C +/- 50%

D +/- 100%



Lower Darling Catchment

Physical Flows Mass Balance Diagram (2013-2014)

39,480

239,692

End of SystemDarling River

Evaporation: 25,521Extractions: 11,765

Basic Rights Extractions: 3,727

River Outflows

Rainfall: 3,039Inflow from Talyawalka Ck: 0

River InflowsUnaccounted difference

(42,488)

All figures in megalitres

Major Storage

Outflow

Inflow

01/07/2013 3,93501/07/2013 1,657 Change: (2,278)

01/07/2013 1,251,28001/07/2013 380,778

Change: (870,502)

Combined Menindee system

Evaporation

Rainfall

Great Darling Anabranch

Lake Menindee Release

Lake Pamamaroo Release

125,060

Lake Cawndilla Release185,350

Total Wetherell Release

68,360

42,516

631,243

0

Anabranch Offtake

Inflow

136,475

123 Denotes negative

Environmental usage

Consumptive usage

89,798

55,243




Water Assets and Water Liabilities For the year ended 30 June 2014

Surface Water Assets ( ) denotes negative 1. Surface Water Storage Accuracy Notes 30-June-14 30-Jun-13

Combine Menindee System A 7 380,778 1,251,280 River B 8 1,657 3,935

Total Surface Water Storage (Asws) 382,435 1,255,215 Change in Surface Water Storage (872,780) (685,635)

Surface Water Liabilities 2. Allocation Account Balance Accuracy Notes 30-June-14 30-Jun-13

Domestic And Stock A1 1 0 0 Domestic And Stock[Domestic] A1 1 0 (0) Domestic And Stock[Stock] A1 1 0 0 Local Water Util ity A1 1 0 0 General Security A1 1 44,459 18,210 High Security A1 1 (0) 0

Total Allocation Account Balance (Lsws) 44,459 18,210

Change in Allocation Account Balance 26,249 (38,333)

3. Environmental Contingency Account Balance Accuracy Notes 30-June-14 30-Jun-13 ECA (Leca) A1 6 30,000 30,000 Change in Environmental Stimulus Flow Account Balance 0 0 Net Surface Water Assets (Asws-Lsws-Leca) 307,976 1,207,005

Change in Net Surface Water Assets (899,029) (647,302)




Changes in Water Assets and Water Liabilities 1 July 2013 to 30 June 2014 (1 of 2)

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

Surface Water Storage Increases Accuracy Notes 2013-14 2012-13 Combined Menindee System

Inflow A 9 136,475 1,678,175 Rainfall B 10 42,516 101,592

River Rainfall C 11 3,039 4,021 Inflow from Releases (Total) A 19 232,900 1,473,208 Inflow from Talyawalka Creek B 12 0 48,620

Total Surface Water Storage Increases (Isws) 414,930 3,305,616

Surface Water Decreases Accuracy Notes 2013-14 2012-13

Combined Menindee System Evaporation B 10 631,243 788,628 Storage releases

Lake Pamamaroo A 13 125,060 314,296 Main Weir A 13 0 0 Lake Wetherell A 13 68,360 339,693 Lake Menindee A 13 39,480 819,219

Storage release (Anabranch) Lake Cawndilla A 13 185,350 184,471

River Evaporation C 11 25,521 33,759 Flows Leaving System

Anabranch Offtake B 17 0 0 End of System A 14 239,692 1,384,560

Extractions from River A 15 11,765 94,633 Basic Rights Extractions (NSW) C 16 3,727 3,727

Total Surface Water Storage Decreases (Dsws) 1,330,198 3,962,986

Unaccounted Volume (Balancing Item) (Usws) D 18 (42,488) 28,265 Net Surface Water Storage Inflow (Isws-Dsws-Usws) (872,780) (685,635)



Lower Darling catchment Changes in Water Assets and Water Liabilities 1 July 2013 to 30 June 2014 (2 of 2)

2. Changes in allocation accounts ( ) denotes negative Allocation Account Increases Accuracy Notes 2013-14 2012-13

Available Water Determinations A1 2 Domestic And Stock 335 139 Domestic And Stock[Domestic] 423 347 Domestic And Stock[Stock] 612 264 Local Water Util ity 10,135 1,200 General Security 76,044 88,167 High Security 7,633 4,516

Supplementary Demand 0 0 Internal Trade - Buyers A1 4 16,033 2,029 Trade in from external A1 4 114,427 83,315 Account Corrections A1 19 0 0

Total Allocation Increases (Iaa) 225,642 154,367

Allocation Account Decreases Accuracy Notes 2013-14 2012-13 Account Usage A1 3

Domestic And Stock 149 139 Domestic And Stock[Domestic] 240 347 Domestic And Stock[Stock] 191 264 Local Water Util ity 4,979 1,200 General Security 147,072 88,167 High Security 4,175 4,516 Supplementary Water 0 0

Account Forfeiture A1 1 Domestic And Stock 185 195 Domestic And Stock[Domestic] 183 76 Domestic And Stock[Stock] 421 348 Local Water Util ity 5,156 8,935 General Security 1,052 815 High Security 993 718

Internal Trade - Sellers A1 4 16,033 2,029 Trade to external A1 4 18,564 84,951

Trade Allocation Account Decreases (Daa) 199,393 192,699 Net Allocation Account Balance Increase (Iaa - Daa) 26,249 (38,333)

3. Change in Environmental Contingency Allowance (ECA) Environmental Contingeny Allowance Increases Accuracy Notes 2013-14 2012-13

Account credit (Leca) A1 8 0 0 Environmental Contingency Allowance Decreases (Deca) Accuracy Notes 2013-14 2012-13

Account usage (Deca) A1 8 0 0

Net Environmental Stimulus Flow Account Balance Increase 0 0

Change in Net Surface Water Assets (Isws - Dsws - Usws - Iaa + Daa - Ieca + Deca) (899,029) (647,302)



Note disclosures



Reconciliation and future prospect descriptions

Lower Darling Catchment: Reconciliation of change in net water asset to net change in physical water storage

2013-14 2012-13

ML ML

CHANGE IN NET SURFACE WATER ASSETS (899,029) (647,302)

Non-physical adjustments

Net Change in allocation accounts 26,249 (38,333)

(38,333)

NET CHANGE IN PHYSICAL SURFACE WATER STORAGE (872,780) (685,635)

Lower Darling Catchment: Reconciliation of closing water storage to total surface water assets

30-June-2014 30-June-2013

ML ML

CLOSING WATER STORAGE

Surface Water Storage 382,435 1,255,215

TOTAL SURFACE WATER ASSETS 382,435 1,255,215

Notes: Al l 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 SURFACE WATER STORAGE AS AT 30 June 2014 (WARP) 382,435 Plus: Water Asset increases within 12months of reporting date (WAI) Minimum Storage Inflow 0 (a) Minimum Usable D/S Tributaries 0 (b) Less: Water assets not available to be accessed and taken or delivered within 12 months of reporting date. (WANA)

Storage Net Evaporation 95,954 (c) Transmission Loss 59,000 (d) Operational Loss 1,500 (e) Essential Requirements 2015-16 30,000 (f) Dead Storage 44,000 7 Volume in River 30 June 2014 1,657 Water assets available to be accessed and taken or delivered within 12 months of reporting date. 232,111

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 44,459 1 ECA 30,000 6 74,459 Future Commitments expected to be delivered within 12 months

of reporting date. (FC)

Indicative Allocations and Basic Rights (g) General Security 53,000 1 High Security 7,633 1 Domestic and Stock 1,370 1 Loca l Water Utility 10,135 1 Bas ic Rights 3,727 16 75,865 Surplus of available water assets over water liabilities and future commitments expected to be settled within 12 months of the reporting date. (SWA) SWA = (WARP + WAI - WANA - WL E – FC)

(h) 0

Notes: (a) The statistical long term annual minimal inf low sequence to storages. For the Low er Darling this f igure is zero. (b) The statistical long term annual minimal inf low sequence downstream of the storage. For the Low er Darling this f igure is

zero. (c) This is an estimate of the annual impact of the net effect rainfall and evaporation on the storages. (d) This is the volume of w ater set aside to account for the losses encountered in the delivery of w ater liabilities and future

commitments. It is estimated at approximately 30 percent of the delivered regulated w ater. (e) This is the volume of w ater set aside to account for the ineff iciencies in the operation of the system taking into account things

such as over ordering of w ater, water orders being met by rainfall after w ater released from storage (rainfall rejection) etc. (f) The Low er Darling catchment puts aside suff icient amount of w ater asset to meet the essential requirements for tw o years.

This f igure represents the essential requirements in year tw o being made up of tow ns, high security, stock and domestic, basic rights, estimated loss to deliver them. This equates to 23,000 megalitres of essential requirements and 7,000 megalitres to deliver.

(g) Indicative Allocation represents a starting allocation of 100 percent for all licence categories including general security, tow ns, domestic and stock and high security to add to the w ater carried over from 2012-13.

(h) This represents the remaining uncommitted w ater available to meet future requirements. In 2013-14 NSW w ere in control of the Lakes w ith all w ater specif ically set aside for Broken Hill w ater supply and the Low er Darling.



Note 1 – Allocation accounts This note is reference for the volume held in the allocation accounts at the time of reporting but also relevant for the various processes that occur to either increase or decrease an allocation account throughout the water year.

The volume of water that is in the licence allocation accounts at the time of reporting is a net balance for the relevant licence category and represents that water that can be carried forward to the next water year as dictated by the carryover rules in place for that year or required under the water sharing plan.

Water that is in the 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.

The accounting presented is relevant to licence category and is therefore inclusive of licences held by environmental holders (these are also detailed separately in Note 5).

Supplementary account water has not been represented as a liability in the accounts as the liability is contingent on river conditions at any point in time.

Data type Derived from measured data

Policy Water Sharing Plan for the NSW Murray and Lower Darling Regulated River Water Source 2003

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

Data accuracy A1 – Estimated in the range +/- 0%

Providing agency NSW Office of Water

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

Methodology The carryover volume of water in the allocation account for each licence category is determined once all transactions and end of year forfeit rules have been applied. Below is list of typical transactions that can apply to an allocation account:

• Available Water Determinations (AWD) (detailed in note 2) • Licenced usage (detailed in note 3) • Forfeiture due to:

o Carryover rules

o Account spillage as a result of AWD

o Licence conversions or cancellations

o Allocation account limits

• Trade of allocation water between accounts (detailed in notes 4)




Additional information Table 4 provides a balanced summary of the water allocation accounts for each category of access licence. Below (Table 3) is a description of each of the table components. Table 3: Explanatory information for allocation account summary

Heading Description

Licence category Licence category, as defined in the Water Management Act 2000, i s sued in the water source

Share This is the total amount of entitlement in the specific l icence category.

Opening The volume of water that has been carried forward from previous years a l location account.

AWD Tota l Available Water Determination - The total annual volume of water added to the allocation account as a result of allocation assessments.

Licences New Increase in account water as a result of issuing new access licences

Cancelled Decrease in account water as a result of licence cancellation

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

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

Account usage

Volume of water that is extracted or diverted from the river and is accountable against the relevant l icence category.

During Year Forfeit Account water forfeited throughout the year as a result of the accounting rules specified in the water sharing plan. Forfeited water may occur due to account limits being reached, conversions between licence categories and various types of other licence dealings.

End of Year Balance Available That part of the account balance that is available to be taken at the conclusion of the water year.

Non Available That part of the account balance that is not 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.



Table 4: Allocation account balance summary for the Lower Darling Regulated River 2013-14

Licence Category Share

30 June 2013 Opening Balance

AWD

Licences Assignments Account usage

During Year

Forfeit

End of Year Balance End of Year

forfeit

Carry Forward New Cancelled In Out Available

Non Available

Domestic and Stock 335 0 335 0 0 0 0 149 0 185 0 185 0

Domestic and Stock [Domestic] 423 (0) 423 0 0 0 0 240 0 183 0 183 0

Domestic and Stock [Stock] 612 0 612 0 0 0 0 191 0 421 0 421 0

Loca l Water Utility 10,135 0 10,135 0 0 0 0 4,979 0 5,156 0 5,156 0

Regulated River (General Security) 78,099 18,210 76,044 0 0 129,241 30,912 147,072 0 45,511 0 1,052 44,459

Regulated River (High Security) 7,633 0 7,633 0 0 1,219 3,685 4,175 0 992 0 993 (0)

Supplementary Water 250,000 0 250,000 0 0 0 0 0 0 250,000 0 250,000 0



Note 2 – Available Water Determination (AWD) 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.

Data type Derived from measured data.

Policy Water Sharing Plan for the New South Wales Murray and Lower Darling Regulated Rivers Water Sources 2003.

• Part 8 – Limits to the availability of water o Division 2 – Available Water Determinations.


Data accuracy A1 – Nil inaccuracy +/- 0%

Providing agency NSW Office of Water.

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

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

Methodology The AWD procedure itself is generally divided into two sections; the available water asset, and system commitments. Once system commitments have been met the available water asset is then available for distribution to the access licence categories in order of priority (see following table). The volume of the announced allocation is expressed as the percentage of share component of the licence. Table 5: Priority of access licence categories

Licence Category AWD Priori ty

General Security Low

High Security High

Conveyance Low

Domestic and Stock 1 Very High

Loca l Water Utility Very High

Available Water Asset – this is calculated by summing the water currently available in storage, future (minimum) inflows to the system, and additional volumes due to recessions of inflows from the current levels to the minimum inflow levels. Also taken into consideration is the reduction of the total inflows to the system for those that arrive too late in the season to be useful.

1 Domestic and Stock is further broken down into three sub categories: Domestic and Stock, Domestic and Stock (Domestic) and Domestic and Stock (Stock). For the purposes of this report and the general purpose w ater account they were all treated as Domestic and Stock.





System Commitments – this is an assessment of the existing commitments that have to be delivered from the Available Water Asset in either the current or future years. Key components include:

• essential supplies include things such as town water supplies, stock and domestic requirements, industrial use and permanent plantings (e.g. orchards, vineyards) and environmental allowances

• undelivered account water is the water that is already in accounts that is yet to be provided

• end of system flow requirement is an estimate of the flow that to pass through the system as a result of operation of the system

• losses which are estimated as the amount of water that will be lost by the system either through evaporation or in the process of delivering the water via transmission losses

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 100 per cent of share component. 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.

Additional information Table 7 contains the allocation summary reports for 2013-14. Below (Table 6) is a table containing report notes to help interpret the report. Table 6: Explanatory information for Allocation Announcement Table

Report Heading Description

Opening Remaining allocation account balances at the conclusion of the previous season that is a llowed 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.

Al location announced volume Volume of water credited to accounts within a l icence category as a result of the announcement made.

Al location cumulative announced volume Cumulative total of the announced volumes for the water year and l icence category.

Al location announced volume % of share This is the announced volume expressed as a percentage of the enti tlement applicable on the particular date.

Al location cumulative announced volume % of share This is the cumulative total percent (of total entitlement) that has been issued on the announcement date (inclusive)

Account ba lance available Sum of water available in allocation accounts that has been made ava ilable to be taken during the season.

Account ba lance not available Water a llocated that is not accessible at this point in time.

Account ba lance total Tota l balance of accounts (available plus not available)

Account ba lance available % of share Account ba lance available expressed as a percentage of share component.

Account ba lance total % of share Account ba lance expressed as a percentage of share component.

Supplementary water Water that i s not a s tored source of water and is only made ava ilable i f an uncontrolled flow event occurs.



Table 7: Allocation Announcements for Lower Darling Regulated River Water Source 2013-14

Date Individual

Announcement Share

Component

Allocation Volume

(ML)

Cumulative Volume

(ML)

Allocation Volume

(%)

Cumulative Volume

(%)

Balance Available

(ML)

Balance Not

Available (ML)

Balance Total (ML)

Balance Available

(%)

Balance Total (%)

DOMESTIC AND STOCK 1-Jul -13 Opening 334 0 0 0 0.0% 0.0% 1-Jul -13 AWD 100.0 % 334 334 334 100.0% 100.0% 334 0 334 100.0% 100.0% DOMESTIC AND STOCK[DOMESTIC] 1-Jul -13 Opening 423 0 0 0 0.0% 0.0% 1-Jul -13 AWD 100.0 % 423 423 423 100.0% 100.0% 423 0 423 100.0% 100.0% DOMESTIC AND STOCK[STOCK] 1-Jul -13 Opening 612 0 0 0 0.0% 0.0% 1-Jul -13 AWD 100.0 % 612 612 612 100.0% 100.0% 612 0 612 100.0% 100.0% LOCAL WATER UTILITY 1-Jul -13 Opening 10,135 0 0 0 0.0% 0.0% 1-Jul -13 AWD 100.0 % 10,135 10,135 10,135 100.0% 100.0% 10,135 0 10,135 100.0% 100.0% REGULATED RIVER (GENERAL SECURITY) 1-Jul -13 Opening 78,099 18,210 0 18,210 23.3% 23.3% 1-Jul -13 AWD 1.0 ML per Share 78,099 78,099 78,099 100.0% 100.0% 96,309 0 96,309 123.3% 123.3% REGULATED RIVER (HIGH SECURITY) 1-Jul -13 Opening 7,633 0 0 0 0.0% 0.0% 1-Jul -13 AWD 1.0 ML per Share 7,633 7,633 7,633 100.0% 100.0% 7,633 0 7,633 100.0% 100.0% SUPPLEMENTARY WATER 1-Jul -13 Opening 250,000 0 0 0 0.0% 0.0% 1-Jul -13 AWD 1.0 ML per Share 250,000 250,000 250,000 100.0% 100.0% 250,000 0 250,000 100.0% 100.0%



Note 3 – Allocation account usage This is the volume of water that is extracted, diverted or measured as usage and is accountable against an access licence.

Data type Measured/administration data

Policy Not applicable

Data accuracy A – Estimated in the range +/- 10%



Methodology Usage information is determined by either on-farm meters that measure extraction, gauges on diversion works or orders/releases when the volume cannot be effectively metered, such as an environmental watering event.

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

• Usage is based on water orders – users place orders for water against an access licence and usages 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 of and rules around each of the licence categories.

Table 8 provides the order in which extractions are apportioned to access licence categories 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.



Table 8: Licence category metered usage apportionment table

Priority Surface water

1 Supplementary

2 Uncontrolled Flow

3 Domestic and Stock

4 Regulated River High Security

5 Regulated River General Security

6 Conveyance

7 Loca l Water Utility

8 Major Water Utility

Table 9: Account usage summary 2013-14

Licence category Account usage (ML)

Domestic and Stock 149

Domestic and Stock [Domestic] 240

Domestic and Stock[Stock] 191

Loca l Water Utility 4,979

Regulated River (General Security) 147,072

Regulated River (High Security) 4,175

Supplementary Water 0

Total 156,806



Note 4 – Temporary Trading/Allocation assignments This represents the temporary trading (allocation assignments) of water either between allocation accounts within the regulated Lower Darling system (internal trading) or trading between the southern connected valleys or the Murray Darling Basin (external). External allocation assignments may be between another water source within NSW or another state

Data type Administration

Policy Water Sharing Plan for the NSW Murray and Lower Darling Regulated River Water Sources 2003

• Part 10 Access licence dealing rules - Clause 50 rules relating to constraints within a water source


Murray Darling Basin Agreement Protocol 2010

• Schedule D — Permissible Transfers between Trading Zones - Part 6 - Restrictions on transfers




Water Ordering and Usage database

Methodology The net internal trade for each licence category is zero for a water year. In order to display the trade information within the statements an internal trade is represented as both a water liability decrease (seller of water) and the equivalent water liability increase (buyer of water).

External trading is represented by either increasing (trading into the Lower Darling from an external water source) or decreasing (trading from the Lower Darling to an external water source) the associated licence category liability.

Additional information The tables below shows the temporary trading figures between licence categories for the Lower Darling. All figures represent a volume in megalitres.

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



Table 10: Lower Darling Regulated River temporary trade summary 2013-14

Trade To (Buyer)

Lower Darling Murrumbidgee NSW Murray South Australia Victoria Total

Genera l Securi ty High Securi ty General Security Genera l

Securi ty High Securi ty Inters tate Transfer

Inters tate Transfer

Trad

e fr

om (S

elle

r)

Lower Darling

Genera l Securi ty 13,114 465 20 654 338 15,860 461 30,912

High Securi ty 2,151 302 1,031 100 100 3,685

Murrumbidgee Genera l Securi ty 14,977 14,977

NSW Murray

Conveyance 8,886 8,886

Genera l Securi ty 74,213 272 74,485

High Securi ty 11,514 180 11,694

South Australia Inters tate Transfer 1,042 1,042

Victoria Inters tate Transfer 3,344 3,344

Total 129,241 1,219 20 1,685 438 15,860 561 149,024



Note 5 – Held environmental water This represents 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 NSW Murray and Lower Darling Regulated River Water Sources 2003




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

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

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.

Additional information The table on the following page provides a summary of held environmental water for 2013-2014. Table 11: Explanatory information for held environmental allocation account summary

Heading Description

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

Opening The volume of water that has been carried forward from previous years a l location account.

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

Licences New Increase in account water as a result of issuing new access licences

Cancelled Decrease in account water as a result of licence cancellation

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

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

Account Usage Volume of water that is extracted or diverted from the river under controlled river conditions and is accountable against the l icence.

During Year Forfeit This is a decrease in the available account balance due to mid year forfeits that may be triggered by things such as licence subdivisions or other dealings.

End of Year Balance Available That part of the account balance that is available to be taken at the conclusion of the water year.

Non Available That part of the account balance that is not 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.



Table 12: Lower Darling environmental account summary 2013-14

Category Share Opening Balance AWD

Licences Assignments Account usage

During Year Forfeit

End of Year Balance End of Year

Forfeit Carry

Forward New Cancel led In Out Avai lable

Non Avai lable

Regulated River (General Securi ty) 48,595 0 48,292 0 0 55,743 25,095 55,243 0 23,697 0 0 23,697

Regulated River (High Security) 897 0 500 0 0 0 500 0 0 0 0 0 0

Supplementary Water 250,000 0 250,000 0 0 0 0 0 0 250,000 0 250,000 0

Table 13: Change in held environmental water 2013-14

Category 30 June 2013 30 June 2014

Difference No. Licences Licenced volume No. Licences Licenced volume

Regulated River (Genera l Securi ty) 5 48,292 5 48,595 303

Regulated River (High Securi ty) 2 500 3 897 397

Supplementary Water 2 250,000 2 250,000 0


39 NSW Office of Water, December 2014

Note 6 – Environmental provisions There a number of planned environmental provisions for the Lower Darling catchment implemented under the water sharing plan, with the aim of enhancing environmental benefits.

A long term extraction limit is set in place that ensures the growth in diversions is contained and the requirements set out under schedule F of the Murray Darling Basin agreement are maintained. If long term average annual diversions exceed this limit, provisions are in place to implement a reduction in the available water determinations until the average diversions are bought back under the required limit.

The plan also states the requirement for a Lower Darling Environmental Contingency Allowance (Lower Darling ECA). The volume of water credited at any time shall be zero if the volume stored in Menindee Lakes is below 480,000 megalitres or has not risen above 640,000 megalitres since it last fell below 480,000 megalitres. Else after allowing for NSW licensed requirements the account will be maintained at 30,000 megalitres minus any usage that has occurred in that water year. The water is typically used to target blue-green algae and other associated water quality issues in the Lower Darling

The plan also makes provisions for held environmental which has been previously detailed in note 5 of this GPWAR.

Data type Measured/Administration Policy Water Sharing Plan for the NSW Murray and Lower Darling Regulated River Water Sources 2003

• Part 3 Environmental Water Provisions • Clause 15 Planned Environmental Water




Data source Not Applicable

Methodology Based on both the rules in the water sharing plan (as detailed in policy above) and advice that no usage has occurred against the ECA since the plan commenced.

Additional Information Table 14: Summary of ECA account balance (figures in ML)

Provis ion Water Year Opening Ba lance

Water Credi ted Usage Ba lance End of Year

ECA

2010-11 30,000 0 0 30,000

2011-12 30,000 0 0 30,000

2012-13 30,000 0 0 30,000

2013-14 30,000 0 0 30,000




Note 7 – Surface water storage – Combined Menindee System This is the combined physical volume of water stored in Lake Menindee, Lake Pamamaroo, Lake Wetherell and Lake Cawndilla 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.

The responsibility of operating Menindee Lakes is shared between the NSW Office of Water and the Murray Darling Basin Authority (MDBA). It falls under the NSW Office of Water’s control when the storage volume falls below 480,000 megalitres until such time as it rises above 640,000 megalitres at which time it falls under MDBA control until it falls back below 480,000 megalitres.





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. Plots on the following page provide the 2013-14 daily storage volumes and percentages. Table 15: Capacity and dead storage summary table

Storage Capaci ty (ML) Dead s torage (ML)

Lake Menindee 629,488 71,190

Lake Pamamaroo 277,725 31,730

Lake Wetherell 192,621 11,800

Lake Cawndilla 631,052 100,970

Total 1,730,886 215,690



Figure 13: Lake Wetherell storage level and effective full storage capacity 2013-14

Figure 14: Lake Pamamaroo storage level and effective full storage capacity 2013-14

Figure 15: Lake Menindee storage level and effective full storage capacity 2013-14



Figure 16: Lake Cawndilla storage level and effective full storage capacity 2013-14



Note 8 – River channel storage The volume of water stored in the river channel on the day of reporting.



Data accuracy B – Estimated in the range +/- 25%


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

Table 16: Summary of river storage calculation components

Symbol Variable Data Source Unit

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

HYDSTRA ML/d

V Volume in each river section. Ca lculated 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 to the nearest day. • Daily flow change between gauging sites assumed to be linear. • Volume in the final reach between Burtundy and Wentworth is estimated as 90% of the

flow at Burtundy



Note 9 – Storage inflow – Combined Menindee System Storage inflow refers to the volume of water flowing into the major headwater storages – Combined Menindee system.





Data sources NSW Office of Water – HYDSTRA

State Water Corporation – Menindee Lakes Storage Monthly Sheets

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.

The inflow figure was derived by carrying out an annual balance across the combined Menindee Storages. While annual figures were used to derive the inflow in some instances the variable resulted from daily summations. The inflow was calculated according to the equation below.

I = ΔS + Se + O + E – R

Table 17: Components for backcalculation of inflow

Symbol Variable Unit

I Inflow ML/year

ΔS Combined Menindee change in s torage volume ML

O Combined Menindee Outflow (see Note 13 for more detail) ML/year

Se Seepage ML/year

R Combined Menindee rainfall (see Note 10 for more detail) ML/year

E Combined Menindee evaporation (see Note 10 for more detail) ML/year

Assumptions and approximations:

• Seepage was assumed to be zero.



Note 10 – Storage evaporation and storage rainfall This refers to the combined volumetric effective on Lake Wetherell, Lake Pamamaroo, Lake Menindee and Lake Cawndilla that is either lost as a result of evaporation, or gained as a result of rainfall.






State Water Corporation – Menindee Lakes Storage Monthly Sheets

Methodology The calculation of the effect of rainfall and evaporation is carried out by using the following formulas.

Rainfall Volume (ML) = Rainfall (mm) x Area (Ha) / 100

Evaporation Volume (ML) = Pan Evaporation (mm) x Pan Factor x Area (Ha) / 100

These formulas were applied on a daily time step with daily evaporation and rainfall data applied across the combined Menindee Storage surface area. A seasonally varied Pan Factor was also applied across the combined Menindee Storage as detailed in the table below. These pan factors were derived after reviewing information in an internal report prepared by J Hayes and G Wright titled ‘Menindee Lakes – Review of Evaporation Estimates’. Table 18: Pan factors utilised for calculation

Storage Pan factor appl ied

Jan, Feb, Mar, Dec 0.7

Apr, May, June, July 0.9

Aug, Sep, Oct, Nov 0.8



Note 11 – 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

Derived from measured data Policy Not applicable

Data accuracy C – Estimated in the range +/- 50%


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 12 – Talyawalka Creek Inflow This represents the inflow into the Lower Darling regulated river that occurs downstream of the headwater storages from Talyawalka Creek. This inflow estimate has been obtained from modelled data as no gauged data is available.


Data type Measured data



Data sources NSW Office of Water: IQQM Model

Methodology The flows are obtained by running IQQM Model for upstream of Menindee Lakes, starting at Wilcannia. The model estimates a flow leaving Talyawalka Creek at Railway Bridge and also the return flow entering the Darling River downstream of the Lakes, which is the volume that is assumed as Lower Darling inflow in this GPWAR.

Additional information Table 19: Summary of Talyawalka Creek at Railway Bridge inflow 2013-14

Location Volume 2012-13 (ML) 6 Volume 2013-14 (ML)

Talyawalka Creek at Railway Bridge 48,620 0

6 The corresponding f igure published in the 2011-12 Peel GPWAR w as incorrect and has been corrected in this report.



Note 13 – Dam releases, river inflow from dam releases The volume of water released from Lakes Wetherell, Pamamaroo, Menindee, Cawndilla. For the first three of these mentioned, 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). For Lake Cawndilla the release which goes to the Great Darling Anabranch is considered as a decrease in outflow only (The anabranch is not included in the GPWAR).





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.

Additional information Table 20: Summary of releases, 1 July 2013 to 30 June 2014

Storage Release (ML) Increase to River Asset (ML)

Lake Cawndilla 185,350 0

Lake Pamamaroo 125,060

232,900 Lake Wetherell - Outlet 68,360

Lake Wetherell – Main Weir 0

Lake Menindee 39,480



Note 14 – End of system flow This refers to flow that leaves the entity and does not return to the entity. The line item excludes water leaving the defined accounting extent for replenishment purposes, or water leaving the defined extent for environment purposes supplied from allocated licenced environmental water (these have been accounted for in separate line items). While the end of system for this GPWAR is considered to be Wentworth, there is no appropriate data available at this site and therefore the data Burtundy has been used as a substitute.






Methodology The end of system flow is calculated by adding the flows at the specified end of system gauging stations and then subtracting the proportion of this outflow that can be attributed to either replenishment flow, or held environmental water. The following table summarises the calculation used to assess the end of system flow for the Darling River reporting entity. Table 21: End of System Flow summary table

System Gauging Station Volume (ML)

Lower Darling 425007 Darl ing River at Burtundy 239,692

Figure 17: End of system flow for Darling River 2013-14



Note 15 – Extractions from River This is the actual volume of water directly pumped or diverted from the Lower Darling regulated river by licence holders.

Occasionally (generally in the case of environmental water) volumes are ordered against a licence account for in-stream benefits or to pass through end of system target points. Additionally water is used outside of the accounted river extent (i.e. from the Great Darling Anabranch). As such the volume reported to be physically extracted from the accounted river is not equal to the amount of water debited against accounts for usage, which has been described in Note 3. The figure stated for extractions from river excludes basic rights extractions, which is reported as a separate line item and detailed in Note 16.






NSW Office of Water – Water Ordering and Usage database

Methodology The extraction from the river is considered to be the total volume metered and debited to the allocation accounts minus any water that can be identified as being used within the system, ordered to be passed through the system, or taken from the Great Darling Anabranch. Figure 18: Reconciliation of extraction from river to account usage 2013-14

Item Volume (ML)

Extractions from River 11,765

Instream usage 0

Licenced water ordered to leave system 0

Environmental use – Great Darling Anabranch 55,243

Consumptive use – Great Darling Anabranch 89,798

Licence Account usage 156,806



Note 16 – Basic rights 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 Water Sharing Plan for the New South Wales Murray and Lower Darling Regulated Rivers Water Sources 2003

• Part 4 Basic Landholder Rights o Clause 18 Domestic and stock rights


Data accuracy C – Estimated in the range +/- 50%


Data source Water Sharing Plan for the New South Wales Murray and Lower Darling Regulated Rivers Water Sources 2003

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 New South Wales Murray and Lower Darling Regulated Rivers Water Sources 2003 (3,727 megalitres)




Note 17 – Unregulated Effluent to Great Darling Anabranch This figure is water that leaves the main Darling River, in high flow events, via an effluent offtake approximately half way between Menindee and Pooncarie.

Data type Calculated from measured data

Policy

N/A



Data source HYDSTRA

Methodology Information from field observations indicates that once flow in the Darling River exceeds approximately 16,000 megalitres, water will begin to flow out the effluent. This volume was estimated by taking the difference between the outflow from Lake Cawndilla and the gauge on the Great Darling Anabranch at Wycot (425013), during periods where the flow at the Darling River at Great Anabranch Offtake exceeds 16,000 megalitres. i.e. there is no data available measuring the direct offtake, however the effluent enters the anabranch between Lake Cawndilla and the Wycot gauge.

For 2013-14 the conditions did not eventuate therefore, no flow was accounted as being diverted at the Darling River at Great Anabranch Offtake.



Note 18 – 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 is 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


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. The opening and closing balance of the river volume was estimated according to Note 8.

Surface Water Unaccounted difference

UD = Rs – Rc + RI - Ro Where: UD = 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, dam releases)



Note 19 – Account corrections This is a line item that is used to correct balances in the accounts. The double entry accounting being applied is a continuous process whereby the closing balance of one year is the opening balance for the following year.

Occasionally corrections will be required for a variety of reasons including when an error is identified in prior year reporting, a balance in the previous year has been since adjusted or when a process that had previously been reported is unable to be supplied and the associated asset or liability must be removed to maintain the integrity of the statements.

This is different to the unaccounted difference component which is a physical volume required to achieve mass balance after all the known processes have been accounted.

Data type Calculated

Accuracy A1 – Nil inaccuracy +/- 0 per cent

Providing agency NSW Office of Water.

Data source Not applicable

Methodology A journal entry is placed in the comparative year to ensure correct opening balances are achieved in the reporting year.

There were no corrections applied for 2013-14.



References

Green D., Shaikh M., Maini N., Cross H. and Slaven J. 1998, Assessment of environmental flow needs for the Lower Darling River. Report to the Murray Darling Basin Commission by the Department of Land and Water Conservation, Centre for Natural Resources, July 1998.

WASB 2012, Australian Water Accounting Standard 1 Preparation and Presentation of General Purpose Water Accounting Reports (AWAS 1), Bureau of Meteorology

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