Regional

water availability

report

Weekly edition

10 June 2019

.com.au

Contents

1. Overview ...... 3

2. System risks ...... 3

3. Climatic Conditions ...... 4

4. Southern valley based operational activities ...... 6

4.1 Murray valley ...... 6

4.2 Lower Darling valley ...... 8

4.3 Murrumbidgee valley ...... 10

5. Central valley based operational activities ...... 14

5.1 Lachlan valley ...... 14

5.2 Macquarie valley ...... 18

6. Northern valley based operational activities ...... 22

6.1 Namoi valley ...... 22

6.2 Gwydir valley ...... 25

6.3 Border rivers ...... 27

6.4 Barwon-Darling River system ...... 29

7. Coastal valley based operational activities ...... 34

7.1 Bega river ...... 34

7.2 Hunter valley ...... 35

7.3 Toonumbar ...... 37

8. Rural Dam Levels ...... 38

Water availability weekly report 2

1. Overview

WaterNSW manages and operates 42 and storages to deliver water for environmental, domestic, town water, stock, industrial and irrigation purposes across the state.

WaterNSW storages provide supplies to all the major river systems in Western NSW, Greater , the Southern Highlands, Shoalhaven Bay as well as the Hunter, Bega, and Iron Pot valleys in coastal NSW.

The total active storage percentage of rural water supplies on 10 June 2019 was 29.2% of the total active storage capacity. This was an increase of 0.5% from last week.

The total storage level of urban water supplies on 10 June 2019 was 52.9% of the total storage capacity. This was a decrease of 0.2% since last week.

2. System risks

• NSW and Commonwealth environmental water releases in the Border and Gwydir valleys for fish habitat maintenance in those valleys is progressing and entering the unregulated Barwon River. A Section 324 temporary water restriction is in place in the Barwon Darling water source to restrict access to this water.

• Flows from the Nebine/Culgoa River reached the Darling River upstream of Bourke on 9 May and Bourke Weir has risen about 1.0m.

• Flows from the Warrego River have reached the Darling River at Louth and Tilpa. These ongoing flows from the Warrego River are possibly going to contribute a small volume into Lake Wetherell at Menindee.

• continues to be below the 480/640GL trigger for NSW control, and four temporary block banks have been constructed to extend drought security beyond January 2019. Releases at Weir 32 ceased in mid-February and cease to flow conditions between the banks has now commenced. The cease to flow conditions increase the possibility of decreasing water quality and fish deaths, with increases in; salinity, pH and Algae, and reduced dissolved oxygen.

• In the Lower Namoi, releases from have ceased and until last month’s rain, cease to flow conditions existed from downstream of Keepit Dam to Walgett. Cease to flow has recommenced from Gunnedah to Walgett.

• The Peel valley is in drought stage 3 and drought planning is underway, including the potential to restrict flows below Dungowan village to secure town water supply.

Water availability weekly report 3

• In the Macquarie the combination of current storage volumes and a continuation of zero inflows will mean that there isn’t enough water to maintain river flows to the whole valley for all of 2019/20. If these zero inflows continue then the priority will be to extend supply for towns and critical industries. This will mean cease to flow is likely to be implemented for the river below Warren and for Duck and Crooked Creeks early in spring. If inflows do not occur at all next year, then all storage water will be depleted before the end of June 2020 and the whole river would then stop flowing.

• The Lachlan system continues to experience very low inflows, only slightly above pre-2004 minimums since the last general security allocation in August 2017. If low inflows continue this winter then the system may record new low inflow records and, based on BOM’s recent outlook, this is a real possibility. If a winter recovery does not eventuate restrictions on availability of general security account water may be required in 2019-20 (drought stage 3).

• Due to drought conditions, end of system daily environmental flow requirements in the Belubula River are being met intermittently, and customers are regularly advised of rescheduling requirements.

3. Climatic Conditions

Figure 1 - Weekly rainfall totals for New South Wales

Water availability weekly report 4

This week’s weather forecast

For the first part of the week, the entire state should receive 1 – 5 mm of rainfall with the exception of the southern regions which are forecast to receive up to 15mm. As the week progresses a further 1 – 5mm should be seen across the entire state with the exception of the southern western region of the state which is predicted to remain dry. Very mild conditions are forecast to continue across NSW with temperatures ranging from – 3 degrees in the south, to 24 degrees in the North. The Snowy Mountains region again is expected to see below zero conditions for the entire week.

Figure 2a – First 4-day Forecast (11 - 14 June 2019) Figure 2b – Following 4-day forecast (15 - 18 June 2019)

Below average winter rainfall is likely for much of New South Wales.

Figure 3 – 3-month rainfall outlook

Water availability weekly report 5

4. Southern valley based operational activities

4.1 Murray valley

Storage and release status

• is currently 18% of active capacity, releasing about 1280ML/d.

• Release downstream of Yarrawonga Weir is about 4,590ML/day and is likely to increase to meet increasing operational needs.

• The Edward River Offtake gates are open, and the flow is currently about 790ML/d and will fluctuate with river levels.

• The Gulpa Creek Offtake gates are open, and the flow is currently about 216ML/d and is likely to vary in line with the flows in Murray channel.

• Stevens Weir level is about 4.14m. Water level upstream of Wakool Canal offtake is about 1.48m. Flow downstream of Stevens Weir has reduced to about 565ML/day and is expected to increase to about 650 ML/d during the week.

• Flows in the Colligen Creek (170ML/day) and Yallakool Creek (170ML/day) are both to remain steady during the week, in accordance with June water sharing plan target of 170ML/d at both locations.

• No flows at Wakool River offtake (0ML/day). It is expected to revert to 30 ML/d late next week.

• Flow in Niemur River at Mallan School is currently about 136ML/d and is likely to increase to about 150 ML/day during this week.

• Merran Creek flows upstream of its confluence with Wakool is about 110 ML/day and is likely to decrease over the week.

• Flow in Wakool River at Stoney Crossing is currently at about 430 ML/day and is likely to decrease over the week.

• Flows at Balranald are currently about 429ML/day and is likely to remain steady in accordance with the June water sharing plan target of 429ML/d.

• Lake Victoria is currently holding about 266GL or 28.8% of active capacity. The flow to South Australia is about 2,780ML/d. ( https://riverdata.mdba.gov.au/system-view )

Environmental water operations

• Current operational requirements downstream of Yarrawonga Weir are now exceeding the minimum flow requested on behalf of environmental water holders and is for the benefit of native fish along the length of the Murray.

Water availability weekly report 6

Water availability

• The latest Water Allocation Statement by DOI-Water confirmed that the general security allocation of zero, while Available Water Determinations (AWD) are 100% for towns, 97% for high security, and 50% for Conveyance. Average carryover into 2018-19 was about 31% of general security share components.

Drought operation measures

• The NSW Murray regulated river water source has advanced to Stage 2, meaning drought operational planning has commenced in preparation for extreme dry conditions that may continue through 2019-20.

• Indicative allocations, if conditions remain dry in 2019/20 are; zero for general security, reduced allocations for conveyance category licences, while the shortfall in meeting all high security and carryover commitments has been met by recent improvements in availability.

Water quality

• Potential Blue Green Algae issues:

– There are no red alerts to report for the Murray or Lower Murray

– Recent Blue Green Algae (BGA) sampling at Lake Hume shows Lake Hume at green alert level.

– For more information visit: Water Quality Algae

Planned supply interruptions:

• Planning is underway to drawdown Torrumbarry weir pool by about 50 cm below FSL. The drawdown may commence from late May and would be refilled by early August.

Water availability weekly report 7

4.2 Lower Darling valley

Storage and release status

• The lakes currently hold about 1% of active capacity. The total storage is about 16 GL.

• Lake Tandure, Lake Cawndilla and Lake Menindee are currently dry, while Lake Pamamaroo holds less than 100ML.

• The release from Wetherell reduced on 12 Feb 2019 and flows at Weir 32 have ceased from mid- February 2019.

• Current level at the block bank near Karoola is about 1.16m. The pipes in the Karoola bank remain closed but will be managed to maintain limited supplies downstream.

• Current level at the block bank near Jamesville is about 1.37m. The pipes at the bank remain closed, except for minor releases to supply permanent plantings immediately downstream.

• Ashvale Bank is currently very low. The pipes at the bank remain closed.

• The average pan evaporation rate at Menindee over the last week was about 2.2 mm/d equivalent to about 290ML lost from the lakes over the week.

Water availability

• The total storage of Menindee Lakes reached the 480GL trigger for NSW control of the lakes on 16 December 2017. The storages will be managed as per the Lower Darling Operations Plan until the storage volume next exceeds 640GL. For more information visit: Lower-Darling Operational Plan.

Drought operation measures

• A temporary water restriction came into effect on 4 December 2018 limiting the taking of water to town water, domestic and stock, permanent plantings, and, from Copi Hollow, high security licences. Gazette

• These restrictions are likely to remain in place after 1 July 2019 and general security allocation will be zero. Carryover water will remain in accounts but remain under the temporary water restriction on use. High security may be restricted.

• The Lower Darling regulated river water source is assessed to be in drought Stage 4, as restrictions limit access to water for critical needs only.

Water availability weekly report 8

• Four temporary block banks viz. Karoola, Court Nareen, Jamesville and Ashvale have been constructed to extend supply to domestic, stock and permanent plantings.

• Pumping by Essential Water to Broken Hill is now met from the Wentworth to Broken Hill pipeline while pumping from Copi Hollow continues at lower rates for Menindee town and pipeline customers.

• The release to Lower Darling River from the storages has ceased and this will impact the river conditions below Weir32. River users are reminded to monitor the river levels, to look for water quality alerts and be aware of snags and other obstructions that may appear while the river ceases to flow below Weir 32.

Water quality

• Red alerts are current for the Darling River at Wilcannia (site N1042) and Pooncarie(N1040)

• Amber Alert for Copi Hollow (site N1094), Lake Wetherell (sites 1 to 4), Lake Pamamaroo (N1093), Darling river at Weir 32 (site N1086), Jamesville (site N1299), Tolarno (N1043) and Court Nareen (site N1301).

• Green Alert for Darling River at Menindee pump station (site N1095).

– For more information visit: Water Quality Algae.

Planned supply interruptions:

• None.

Water availability weekly report 9

4.3 Murrumbidgee valley

Storage and release status

• is currently at 30% of active capacity, releasing about 400ML/d and is likely to vary marginally as per minimum transparency/translucency rules.

• is currently at 39% of active capacity, releasing about 570 ML/d and likely to decrease to 560 ML/d over the week.

• The Beavers Creek Offtake remains fully open as per rules from May to August period environment rules and flows have recommenced due to higher river levels.

• Berembed Weir is currently at about operational full supply level (about 4.94m) and likely to remain steady during this week.

• Bundidgerry storage is currently at 3.98m and will be actively used for re-regulation of flows.

• Gogeldrie Weir is currently at 6.09m, it is likely to remain steady during the week. The weir is being actively used for re-regulation to capture any system surplus.

• Tombullen storage is at about 2.77m (7.6 GL, 69% of active storage volume) releasing about 10 ML/d and likely to remain steady over the week.

• Hay Weir is currently at about 8.58m and is likely to remain around full supply level of 8.6m.

• Maude Weir is at about 5.85m, close to full supply of 5.9m, and is being actively used for re- regulation to capture any system surplus and then to meet downstream system demands.

• Redbank Weir is at about 4.10m, well below the full supply of 5.6m, and is likely to decrease further during the week.

• Flows at Balranald are currently about 429ML/day and is likely to remain steady in accordance with the June water sharing plan target of 429ML/d.

• The current diversion into Yanco Creek is about 230 ML/d and is expected to gradually decrease to 220 ML/d during the week.

• No flows to Billabong system via Finley Escape.

• Delivery to Yanco-Billabong system via Coleambally Irrigation Escapes (CCD and DC800) is less than 20ML/day combined as CICL operations drain parts of their system for the close of their season. These flows are expected to reduce further during this week.

Environmental water operations

• The NSW environmental water holder is planning a small delivery of up to 1,500ML to Lowbidgee assets via North Caira channel.

Water availability weekly report 10

Water availability

• For Inter Valley Transfer (IVT) account from Murray to Murrumbidgee refer to WaterNSW website IVT Ordering. The IVT balance recently increased above 15GL meaning that trade into the Murrumbidgee can recommence until the account balance reduces to zero.

• Intravalley trade closes in June, Interstate trade closes in May and June, while intervalley trade does not close in any month and remains open while the IVT balance allows trade.

• The latest Water Allocation Statement by DOI-Water confirmed the Available Water Determinations (AWD) are 100% for towns and 95% for high security, while general security is now 7%. Carryover into 2018-19 is a volume equivalent to 22% of general security share components.

Drought operation measures

• The Murrumbidgee regulated river water source has moved to drought Stage 2 meaning drought operational planning has commenced in preparation if extreme dry conditions continue through 2019-20.

• Indicative allocations, if conditions remain dry in 2019-20 are; zero for general security, high security (95%) and carryover commitments (estimated at about 7% of share component) are forecast to be deliverable. However restricted allocations are likely for conveyance category licences for Murrumbidgee Irrigation and Coleambally.

Water quality

• Potential Blue Green Algae issues:

– Lake Albert in Wagga Wagga is on a Green alert for blue-green algae. More information can be obtained from the following link: Lake Albert - Wagga City Council

– Lake Wyangan South in Griffith also has a Red status for blue green algae. For more information select the following link: Murrumbidgee Irrigation.

– Lake Wyangan North in Griffith has an Amber status for blue green algae. For more information select the following link: Lake Wyangan.

– The Hay weir at Leonard Street and Murrumbidgee River at Maude Weir Buoy are on a Green alert status.

– Green alerts are current for Burrinjuck Dam at Good Hope, Woolgarlo and Amber alert downstream of the dam wall.

– Green alerts are current at Gogeldrie Weir, Hay weir Buoy and Balranald,

– Other sites have no alerts. For more information visit: Water Quality Algae.

Water availability weekly report 11

Planned supply interruptions:

• Maintenance of Tarabah Weir is underway. However, the structure is being operated manually to deliver about 50ML/d below the structure.

• Planning is underway for installation a new gate at Spillers Regulator at the Washpen Creek; awaiting a suitable low flow condition.

• Planning is underway for the maintenance of Yanco Weir as the maintenance team is awaiting a suitable window of low flows. This is more likely to be in early May, subject to watering requirements in the Colombo Creek – Billabong systems.

• A series of maintenance tasks along the North Redbank Channel are progressing as scheduled to early June 2019. During the outage the offtake regulators into the North Redbank Channel will remain fully closed. The project teams will undertake works on several sites along the North Redbank Channel.

• Maintenance work at Berembed Weir and Redbank Weir are being planned to commence this winter.

– The works at Redbank Weir commenced late May 2019 on the superstructure, while the coating of gates is expected to commence in late May or early June (4-week period) subject to water level in the weir. While it is a very high priority maintenance task, WaterNSW operations will consider the useability of re-regulation storages to capture any system surplus and minimise operational wastage by maximising the use of Redbank Weir.

– The works at Berembed Weir is expected to start by late June and continue for 4-weeks subject to irrigation demand in the Murrumbidgee Irrigation main canal.

Water availability weekly report 12

Burrinjuck Dam forecast storage capacity updated mid - April 2019

1,200

1,000

800

600

400

EndMonth of Storage (GL) * Including Snowy releases

200

0

Wet scenario (20%) Average scenario (50%) Dry scenario (80%) Extreme dry scenario (99%) Actual

Blowering Dam forecast storage capacity updated mid - April 2019 1,800 1,600 1,400 1,200 1,000 800 600

EndMonth of Storage (GL) 400 * Including Snowy releases 200 0

Wet scenario (20%) Average scenario (50%) Dry scenario (80%) Extreme dry scenario (99%) Actual

Water availability weekly report 13

5. Central valley based operational activities

5.1 Lachlan valley

Storage and release status

• is currently 22% of capacity and releasing 15ML/d. Releases are forecast to be around 15-30ML/d for rest of the week.

• is currently 28% of capacity and releasing 850ML/d. Releases are forecast to be around 800ML/d later in the week.

• Lake Cargelligo is currently 51% of capacity and the level is likely to reduce to remain around 50%

• Releases downstream of Brewster Weir are currently around 560ML/d. Releases are forecast to stay around 500-650ML/d this week.

• Annual S&D replenishment flows into Merrowie Creek started on 18th May. Merrimajeel/Muggabah are planned to start from 17 June and 15 June for Willandra Creek. Due to the prevailing drought conditions it is prudent that these systems are replenished efficiently and as much as possible from tributary inflows. These starting dates are likely to be adjusted following further consultations with the landholders or with any rain and tributary flows beforehand.

Environmental water operations

• Licenced Environmental water will be delivered to Booligal to create a pulse for the Cumbung, this will begin to arrive around 11 June.

• There will be a pulse for 10 days into Booberoi Creek, which started on the 6 June.

• Due to drought conditions, end of system daily environmental flow requirements in the Belubula River are being met intermittently with the contribution from tributaries.

Water Availability

• The 14 May Water Allocation Statement confirmed zero for general security and the initial Available Water Determinations (AWD) of 100% for towns, S&D and high security. Carryover into 2018-19 in Lachlan River was about 369GL, equivalent to about 62% of general security share components.

• It is estimated that a combined dam and tributary inflow volume of more than 181,000 ML was required in May before a further allocation could be made in the Lachlan River. Inflows received to date in May have been negligible.

Water availability weekly report 14

• DOI (Water) in their Water Allocation Statement (WAS) for May 2019 indicates a zero announcement for general security and the possibility of reduced allocations for high security on 1 July 2019 if conditions remain dry. The WAS also has provided estimates of general security remaining water deliverability in 2019-20. The aim is to assist water users with their end of year water management decisions and upcoming water year planning.

• May WAS by DOI Water can be viewed at: WAS

• These are indicative improvements only and are not guaranteed allocations. Estimates may change based on weather variability, water management decisions and other events. This means water users should use this information with caution and at their own risk, as it projects many months ahead.

• The assessment for the table above is based on water delivery operations in 2019-20 provided under drought stage 3 and 2020-21 under severe drought stage 4. NSW extreme events policy can be viewed at Extreme Events Policy

• The meeting with Belubula Landholders Association at Canowindra on 3 June 2019 to discuss river operation and delivery options for 2019/20 was well-attended with the majority of active water users. Following a detailed presentation on the HS and GS account balances, the volume in Carcoar and the rules on uncontrolled flow access and end of system flows, there was a wide-ranging discussion on river management options for 2019/20.

• There was unanimous support from the meeting for WaterNSW to make the following recommendations to DoI-Water on operations in 2019/20:

– Access to water held on GS accounts should be unrestricted from 1 July to 30 September and expected to be delivered primarily from downstream tributary inflows. Releases from Carcoar will only be made to deliver water upstream of Needles.

Water availability weekly report 15

– From 1 October access to GS account balances may be restricted.

– If there are no further inflows the AWD for HS licences on 1 July to be 50%, and 60% for S&D.

– Access to uncontrolled flows will be available in accordance with current WSP rules.

– The effective available water for uncontrolled flow access should be calculated based on the restriction applied to GS account balances.

– Supplementary flow access to be in accordance with current WSP rules.

– If inflows occur the HS allocation to increase at a higher rate than the release of suspended GS account balances.

– Allow trades of GS and HS allocations upstream.

– Target 2,500 ML in Carcoar at the end of the 2019/20 water year.

– The end of system (EOS) flow rule should immediately be formally suspended.

– There was concern that the Flyer’s Creek ‘wet’ trigger of the 120-day moving average exceeding 40 ML/day should not result in automatic reinstatement of the EOS flow rule, due to the risk that dam levels may not recover sufficiently, and advice that a further review of this should be undertaken with the Belubula Landholders Association.

Water Quality

• Latest BGA samples show that Lake Cargelligo Boatshed are on amber alert. Lake Cargelligo Outlet and Lake Cargelligo TWS and lake Brewster inlet are on Green alert.

• Storage results (23rd May) show that the overall productivity is starting to decline across the storage. The assemblage is currently variable across the storage. The junction of the Lachlan and Sandy Rvrs remains at red alert awaiting another clear result. All other sites remain at green alert.

• Some river flow is being circulated through the Lake Cargelligo with the intention of improving water quality in the channels connecting the lakes and the river.

Planned supply interruptions:

• Nil.

Water availability weekly report 16

Wyangala Dam forecast storage volume chance of exceedance 120%

100%

80%

60%

40% Storage capacity(%) 20%

0%

Jul-16 Jul-17 Jul-18 Jul-19

Jan-17 Jan-18 Jan-19 Jan-20

Sep-16 Sep-17 Sep-18 Sep-19

Mar-17 Mar-18 Mar-19 Mar-20

Nov-16 Nov-17 Nov-18 Nov-19

May-17 May-18 May-19 May-20

WET 20% COE Median 50% COE DRY 80% COE Minimum Actual

Water availability weekly report 17

5.2 Macquarie valley

Storage and release status

• is at 5.4% of capacity and currently releasing around 300ML/d. Releases are forecast to be between 250-330ML/d this week to meet demands, primarily for town water supply with some small irrigation demands.

• The level in Burrendong Dam is expected to drop steadily to about 5% by end of the water year. Burrendong Dam has been drawn below 10% on five similar occasions (June 1995, Jan 1998, Apr 2003, May 2004 and Jan 2007).

• is currently 33% of capacity and releasing 40ML/d. Releases are forecast to be between 30-40ML/d for the rest of this week. Releases for the bulk water transfer to Burrendong Dam ceased on 25 Jan 2019. More info on WaterNSW website Link

• There have been inflows of about 49,384 ML into Burrendong Dam since 1 January. The combination of Windamere releases and Burrendong inflows has resulted in Burrendong Dam being higher than previously forecast for this stage of the drought planning.

• If conditions remain dry, a second phase of the transfer will occur in late 2019, leaving a minimum of 70GL in Windamere Dam, which provides a very secure supply for local demand for the next five to seven years.

Environmental water operations

• About 300 ML of licenced environmental water has been delivered via Albert Priest Channel to maintain water levels in the lower Nyngan Weir Pool for refuge sites for native fish.

• Currently, about 1000ML of licenced environmental water has been delivered to Ewenmar Creek for refuge sites for native fish, using the channel infrastructure of Tenandra Irrigation Scheme.

• Translucent environmental water from Windamere Dam is deliverable all through the year. In January 2019 there were two inflow events to Windamere Dam that were delivered to downstream as translucent environmental flows totalling 2,600 ML.

• Translucent environmental water from Burrendong Dam is deliverable from 15 March if flow triggers are met as provided for in the Water Sharing Plan, although OEH have indicated this is unlikely to be called while the valley remains in severe drought.

Water availability

• Rain at the end of March had produced some good flow in the Talbragar River. Most of this flow has been diverted to the Lower Bogan River via Gunningbar Ck, and into Marra Ck for Stock

Water availability weekly report 18

and Domestic (S&D) replenishments. The duration and the volume of the flows has not be adequate to complete these S&D flows, but it may be possible with the next rain events, however no significant rain events were observed in the last few weeks.

• About 1,600 ML of the flows from the Talbragar river was delivered downstream of Marebone Weir, 900 ML in river and 700 ML into the Bulgeraga Ck.

• It is estimated that inflows of around 260 GL were required in May before an increment in Available Water Determination could be made. Inflows in May were negligible.

• Carryover evaporation reduction was applied to remaining carryover balances in HS and GS sub-accounts in Macquarie and Cudgegong Rivers for March quarter in 2018-19. A 6.6% reduction was applied to Macquarie River licences and a 1.9% reduction was applied to Cudgegong River licences. A 6.6% reduction was also applied to EWA Carryover balance. Carryover evaporation reduction is not applied to carryover allocations held in drought suspended accounts.

Drought operation measures

• The Macquarie is in drought Stage 4, the highest level under the Incident Response Guide.

• The combination of current storage volumes and a continuation of zero inflows will mean that there isn’t enough water to maintain river flows to the whole valley for all of 2019/20. If these zero inflows continue then the priority will be to extend supply for towns and critical industries. This will mean cease to flow is likely to be implemented for the river below Warren and for Duck and Crooked Creeks early in spring. If inflows do not occur at all next year, then all storage water will be depleted before the end of June 2020 and the whole river would then stop flowing.

• Indicative allocations, if conditions remain dry in 2019/20 are; zero for general security and reduced allocations for higher security entitlements such as Local Water Utility, domestic and stock, and high security.

• The timing of all S&D replenishments in 2019 will depend on further rainfall events, dam inflows, and contributions from downstream tributaries, rather than dam releases.

• The Temporary Water Restriction Order restricting access to 70 per cent of the 1 July 2018 balance of general security and environmental accounts (including EWA) in the Macquarie remains in place and is likely to be extended to all carryover on 1 July 2019.

• Cudgegong regulated river access licences, including general security carryover, are not restricted.

• Any inflows received will be used to improve the drought management operations in 2019-20 from stage 4 to stage 3 prior to easing the current restrictions and drought management operations further. The Macquarie–Castlereagh incident response guide can be viewed at Incident response guide Macquarie.

Water availability weekly report 19

• The actual inflows to Burrendong Dam since the last AWD in August 2017 total about 88 GL to end of April 2019. This is only 36% of the previous record low inflow of about 246 GL for the 21 months ending in April.

• This drier than historical minimum inflow confirms that the system has entered into a new drought of record for Burrendong Dam, and the next few months inflows will be important for planning next season’s operations.

Water quality

• Burrendong algal results for the 8th May show the assemblage across storage is starting to shift away from cyanobacteria towards diatoms. The Microcystis sp. presence has been noted at the Dam Wall. Downstream showed few cyanobacteria. Storage remains at amber alert.

• Windamere algal results for the for 27th May show a major decline in cell counts across the storage, likely due to the change in weather in the area. Microcystis sp. still dominates the assemblage at all upstream locations. Downstream results show few cyanobacteria are present. Windamere remains at red alert awaiting another low result.

• Due to presence of toxic BGA below Windamere Dam, the position of the trash rack is lowered to 12.69m – 15.69m below the water surface.

• Works to reinstate the temperature curtain at Burrendong Dam have been completed and the commissioning phase has commenced. The curtain is fully lowered due to low storage levels.

Planned supply interruptions:

• Nil

Water availability weekly report 20

Burrendong Dam forecast storage volume - chance of exceedance 140%

120%

100%

80%

60%

40% Storage capacity(%) 20%

0%

-20%

WET 20% COE Median 50% COE DRY 80% COE Minimum Actual

Water availability weekly report 21

6. Northern valley based operational activities

6.1 Namoi valley

Storage and release status

• is under 2.3% of active capacity and is currently releasing around 11 ML/d for the Upper Namoi. The earlier bulk water transfer to Keepit Dam is complete.

• Keepit Dam is at less than 1% of active capacity and releases have ceased.

• is at 24% of active capacity and currently releasing 21ML/d.

• Flows from the recent tributary flows reached Walgett and raised the level in the Barwon River weir.

• The Pian Creek replenishment flow was not able to be delivered in the usual manner so unless conditions improve, other supply arrangements may need to be made.

• Supply on demand currently applies for the Upper Namoi and the Peel Valley, although at reducing flow rates.

Environmental water operations

• Environmental water was delivered as part of the lower Namoi block release. This water was ordered and delivered downstream of Gundigera Weir in November and December.

• In the Peel valley there is currently 1.9GL of planned environmental water plus a small amount of held environmental water. There are not any current orders for the release of water from either of these accounts.

Water availability

• There is currently a shortfall of more than 76GL before there is likely to be an AWD increment in the Lower Namoi valley.

Drought operation measures

• The Upper Namoi is in drought Stage 3, while the Lower Namoi is at Stage 4, the highest level under the Incident Response Guide. The Peel valley is on Stage 3 as planning is underway for reduced availability in 2019/20.

• The Peel valley is in drought stage 3. Drought planning underway, including the potential to restrict flows below Dungowan to secure town water supply. Indicative allocations in the Peel, if conditions remain dry in 2019/20 are; zero for general security and 50% for higher security

Water availability weekly report 22

entitlements, and 70% for local water utility, however deliverability downstream of Dungowan may not be continuous.

• Indicative allocations in the Namoi, if conditions remain dry in 2019/20 are; zero for general security, full allocations for local water utility, stock and domestic categories, while regulated high security is likely to receive 75% allocation. However deliverability of this water will rely on tributary flows and/or improved storage volumes.

• No further block releases are planned for the Lower Namoi until inflows occur.

Water quality

• Recent sampling for BGA indicates that Chaffey Dam is on an amber alert downstream of the dam and an amber alert in the storage.

• Split Rock Dam is on an amber alert in the storage and on an amber alert downstream.

• Keepit Dam is on an amber alert in the storage and on an amber alert downstream.

Planned supply interruptions:

• Mollee fish way is currently unavailable due to infrastructure failure.

Keepit - forecast storage volume chance of exceedance 450

400

350

300

250

200

150

100

50 Storage (GL) capacityStorage

0 Apr-18 Jul-18 Oct-18 Jan-19 Apr-19 Jul-19 Oct-19 Jan-20 Apr-20 Jul-20 Oct-20 Jan-21 Minimum 99% COE DRY 80% COE Median 50% COE WET 20% COE Actual

Water availability weekly report 23

Split Rock - forecast storage volume chance of exceedance 250

200

150

100

50 Storage (GL) capacityStorage 0 Apr-18 Jul-18 Oct-18 Jan-19 Apr-19 Jul-19 Oct-19 Jan-20 Apr-20 Jul-20 Oct-20 Jan-21 Minimum 99% COE DRY 80% COE Median 50% COE WET 20% COE Actual

Chaffey Dam - forecast storage volume chance of exceedance 100

80

60

40

20 Storage (GL) capacityStorage

0 May-18Aug-18 Nov-18 Feb-19 May-19Aug-19 Nov-19 Feb-20 May-20Aug-20 Nov-20 Feb-21 Minimum 99% COE DRY 80% COE Median 50% COE WET 20% COE actual

Water availability weekly report 24

6.2 Gwydir valley

Storage and release status

• is at 9.3% of active capacity and is currently releasing 595 ML/d to meet environmental orders for fish refuge. Release is likely to gradually decrease to 200 ML/d later in the week.

Environmental water operations

• Releases of about 595GL to maintain fish refuge areas in parts of the Gwydir system commenced from to the Carole Ck on 2 April 2019. Releases from Copeton started on 16 April, debited at the dam, and likely to continue at reduced rates until ceasing on 23 June.

Water availability

• Inflows of about 50GL are required to refill the Essential Requirements and Delivery Loss accounts before any increase in general security AWD is possible.

Water quality

• Recent Blue Green Algae (BGA) sampling at Copeton shows Copeton at a Red level.

Drought operation measures

• The Gwydir is in drought Stage 3 as the drought is deepening and tougher measures are needed to protect critical human needs. Management action will focus on ensuring water is available for critical needs for as long as possible.

• Indicative allocations, if conditions remain dry in 2019/20 are; zero for general security and possibly full allocations for higher security entitlements such as local water utility, stock and domestic and regulated high security. However, deliverability will rely on downstream tributary contributions and infrequent block releases.

Planned supply interruptions:

• No supply interruptions are expected.

Water availability weekly report 25

Copeton - forecast storage volume chance of exceedance 1250

1000

750

500 Storage (GL) capacityStorage 250

0

Minimum 99% COE DRY 80% COE Median 50% COE WET 20% COE Actual

Water availability weekly report 26

6.3 Border rivers

Storage status

• is at 5% of capacity and releasing around 15ML/d (minimum release).

• Glenlyon Dam is at 9% of capacity. Releases ceased.

• Releases from Boggabilla Weir are currently around 10ML/d. Most of the environmental water released from Glenlyon already passed through the weir.

Environmental water operations

• Releases of about 7.4 GL from Glenlyon Dam to maintain fish refuge areas in the Border and Barwon Rivers, ranging between 200ML/d and 620 ML/d commenced on 24 April and ceased on 13 May. Operations update.

• This environmental water arrived at Mungindi on 23 May and around 1,450ML has passed Mungindi to date.

Water availability

• The Available Water Determinations (AWD) are 100% for towns and high security, while general security A-class is 32.8% and general security B-class is zero. Total carryover into 2018-19 was around 53% of general security share components.

Drought operation measures

• The Border Rivers is in drought Stage 3. Customers are advised that if dry condition persists, future deliveries, including essential supplies, will be grouped together (block releases) to improve delivery efficiencies.

• Indicative allocations, if conditions remain dry in 2019/20 are zero for general security and full allocations for towns, domestic and stock, and high security. However, access to carryover may be restricted to 50%, and deliverability of all water will be via block releases.

Water quality

• Recent Blue Green Algae (BGA) sampling at Pindari shows Pindari is at a red level.

Planned supply interruptions:

• No supply interruptions are currently forecast.

Water availability weekly report 27

Pindari forecast storage volume chance of exceedance 350

300

250

200

150

100 Storage capacity(GL) 50

0

Wet 20% COE Median 50% COE Dry 80% COE Minimum 99% COE Actual

Glenlyon forecast storage volume chance of exceedance

250

200

150

100

Storage capacity(GL) 50

0

Wet 20% COE Median 50% COE Dry 80% COE Minimum 99% COE Actual

Water availability weekly report 28

6.4 Barwon-Darling River system

River flow status

• Rain on 30 March had led to small inflows from the Namoi, into Walgett Weir, and Macquarie/Castlereagh River water along the Barwon to refill the Brewarrina Weir pool with a small flow over that weir.

• The environmental release from the Border valley reached Mungindi on 23 May with around 1,450ML over the weir to date. Flow reached Mogil Mogil on 8 June. Gwydir valley releases reached Collarenebri on 27 May with around 6,000ML recorded to date. Flow is currently at Tara. These releases are likely to flow down the system, to Walgett, and then Brewarrina. The flows may reach Warraweena but are unlikely to reach Bourke.

• Flows from the Nebine/Culgoa River reached the Darling River upstream of Bourke on 9 May and Bourke Weir has risen about 1 m.

• Flows in the Darling have recommenced between Bourke and Louth because of local rainfall over the Easter weekend and ongoing inflows from the Warrego River that are contributing to the flow at Louth. This flow has now reached Tilpa and expected to reach Wilcannia this week.

• Other sections of the river system between Mungindi to Wilcannia are currently at cease to flow condition and are forecast to remain this way until there is a significant rainfall event, or until the environmental releases from Copeton and Glenlyon Dams reach the system over coming weeks.

• The Barwon-Darling Rivers travel through a very arid environment with significant losses from the system due to high evaporation and long travel times. It is very difficult to accurately forecast downstream flows as local conditions can vary significantly over the number of weeks it takes the water to travel along the river. In addition, sections of the river have ceased to flow for an extended time and significant losses will occur with wetting up the river bed along these sections and refilling weir pools and natural holes in the river. The below summarises the current forecast estimates of flows along the system and timing of the flows reaching sections. This information will be regularly updated as the event progresses.

Water availability weekly report 29

Observed volume Total forecast Flow River station Gauging station (ML) volume – including arrival/expected observed (ML) arrival date 1,450 1,500-1,700 23 May 2019 Barwon at Mungindi 416001

590 600-700 27 May 2019 Barwon upstream of 416050 Presbury

40 100-200 9 June 2019 Barwon at Mogil Mogil 422004

5,990 11,000-15,000 27 May 2019 Barwon at Collarenebri 422033

422025 2,560 8,000-12,000 5 June 2019 Barwon at Tara

Barwon at Danger Bridge 422001 0 6,000-9,000 11-15 June 2019 (Walgett) 0 4,000-7,000 19-24 June 2019 Barwon at Boorooma 422026

0 3,000-6,000 22 – 26 June 2019 Barwon at Geera 422027

0 1,000 -3,000 30 June – 7 July 422002 Barwon at Brewarrina 2019

0 0-1000 7-12 July 2019 Barwon at Bemeery 422028

0* 0- 500 14 – 20 July 2019 Darling at Warraweena 425039

0 0 Darling at Bourke 425003

21,660 22,000 -25,000 29 April 20019 Darling at Louth 425004

12,320 13,000-16,000 13 May 2019 Darling at Tilpa 425900

0* 4,000-7,000 11-16 June 2019 Darling at Wilcannia 425008

0 0-2,000 12-25 June 2019 Lake Wetherell 425020

*Currently small flow exists. Inflow from Culgoa generated flow at Warraweena. Small flow at Wilcannia from local rainfall event.

Water availability weekly report 30

Environmental water operations

• Releases of Held Environmental water to maintain fish refuge areas in the Barwon River from Copeton Dam have commenced on 16 April and are scheduled to continue to mid-June at reducing rates. Releases from Glenlyon Dam commenced on 24 April and ceased on 13 May.

• A Section 324 temporary water restriction is in place to restrict irrigation access to this water. This restriction is extended from Tilpa to Lake Wetherell to allow the Warrego water to re-establish flows as far down the system as possible. News.

• Planned Environmental Water (PEW) is water in the system that is below the commence to pump conditions for access licences.

Water Availability

• The table below sets out the river management zones and access availability using daily average data to 6 am, these are provided as an indication only and access may have changed during the 24-hour period.

Drought operation measures

• The Barwon Darling unregulated river water source is assessed to be in Stage 4. A Temporary water restriction order is in place from Mungindi to Lake Wetherell to ensure critical water needs.

Water availability weekly report 31

Classification River section Gauging station

03-06-19 04-06-19 05-06-19 06-06-19 07-06-19 08-06-19 09-06-19

No No No No No No No Mungindi to Boomi river conf 416001 - 416050 access access access access access access access No No No No No No No Boomi river confluence to U/S 416050 - 422004 Mogil Weir access access access access access access access No No No No No No No Mogil Weir 422004 access access access access access access access No No No No No No No D/S Mogil to Collarenebri 422,004- 422003 access access access access access access access

422003 - 422025 No No Collarenebri to U/S Walgett Weir Class A* Class A* Class A* Class A* Class A* access access

No No No No No No No Walgett Weir 422001 access access access access access access access No No No No No No No 422001- 422026 D/S Walgett to Boorooma access access access access access access access

No No No No No No No Geera to Brewarrina 422027- 422002 access access access access access access access No No No No No No No Brewarrina to Culgoa river 422002- 422028 junction access access access access access access access No No No No No No No Culgoa river junc to Bourke 425039- 425003 access access access access access access access No No No No No No No Bourke to Louth 425003- 425004 access access access access access access access

Louth to Tilpa 425004- 425900 Class A* Class A* Class A* Class A* Class A* Class A* Class A*

No No No No No No No Tilpa to Wilcannia 425900- 425008 access access access access access access access No No No No No No No Wilcannia to U/S Lake Wetherell 425008 access access access access access access access

* Access is restricted due to s324 order. Access is not available even though observed flows would normally indicate access.

Water availability weekly report 32

WaterNSW HYPLOT V133 Output 11/06/2019 Period 18 Month 01/01/2018 to 01/07/2019 2018-19 416001 BARWON R @ MUNGINDI 141.00 1 Day Mean Discharge (ML/d) CP 2000 1600 1200 800 400 0 416050 BARWON U/S PRESBURY 141.00 1 Day Mean Discharge (ML/d) CP 2000 1600 1200 800 400 0 422004 BARWON @ MOGIL MOGIL 141.00 1 Day Mean Discharge (ML/d) CP 2000 1600 1200 800 400 0 422003 BARWON @COLLARENEBRI141.00 1 Day Mean Discharge (ML/d) CP 2000 1600 1200 800 400 0 422025 BARWON @ TARA 141.00 1 Day Mean Discharge (ML/d) CP 2000 1600 1200 800 400 0 422001 BARWON @ DANGAR BDGE141.00 1 Day Mean Discharge (ML/d) CP 2000 1600 1200 800 400 0 422026 BARWON @ BOOROOMA 141.00 1 Day Mean Discharge (ML/d) CP 2000 1600 1200 800 400 0 422027 BARWON @ GEERA 141.00 1 Day Mean Discharge (ML/d) CP 2000 1600 1200 800 400 0 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun

WaterNSW HYPLOT V133 Output 11/06/2019 Period 18 Month 01/01/2018 to 01/07/2019 2018-19 422002 BARWON @ BREWARRINA 141.00 1 Day Mean Discharge (ML/d) CP 2000 1600 1200 800 400 0 422028 BARWON @ BEEMERY 141.00 1 Day Mean Discharge (ML/d) CP 2000 1600 1200 800 400 0 425039 DARLING@WARRAWEENA 141.00 1 Day Mean Discharge (ML/d) CP 2000 1600 1200 800 400 0 425003 DARLING@BOURKE TOWN 141.00 1 Day Mean Discharge (ML/d) CP 2000 1600 1200 800 400 0 425004 DARLING@LOUTH 141.00 1 Day Mean Discharge (ML/d) CP 2000 1600 1200 800 400 0 425900 DARLING@TILPA 141.00 1 Day Mean Discharge (ML/d) CP 2000 1600 1200 800 400 0 425008 DARLING@WILC. MAIN C 141.00 1 Day Mean Discharge (ML/d) CP 2000 1600 1200 800 400 0 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun

Water availability weekly report 33

7. Coastal valley based operational activities

7.1 Bega river

Storage and release status

• is at 99% of capacity and releasing around 20 ML/d.

• Unregulated flow conditions have ceased.

Environmental water operations

• No current additional operations.

Water availability

• An AWD increment of 20% announced on 19 Feb 2019 and takes the total availability for the general security licences for the year to 65%.

Water quality

• Recent BGA sampling at Brogo indicates a green alert level is maintained.

Planned supply interruptions:

• Nil

Brogo Dam forecast storage volume chance of exceedance 10,000 9,000 8,000 7,000 6,000 5,000 4,000 3,000 2,000

Storage capacity(ML) 1,000 0

WET 20% COE Median 50% COE DRY 80% COE Minimum Actual

Water availability weekly report 34

7.2 Hunter valley

Storage and release status

• is currently at 52% of capacity and releasing around 120 ML/d. Releases are forecast to remain steady for the week.

• is at 54% of capacity and releases are currently around 90 ML/d. Releases are forecast to remain steady during the week.

• is at 85% of capacity and releasing 25 ML/d. Releases are forecast to remain around this rate.

Environmental water operations

• No current additional operations.

Water availability

• All licence categories have 100% availability.

• DOI (Water) in their Water Allocation Statement (WAS) for March 2019 has stated that the preliminary forecast for the Hunter regulated river water source indicates that 100 per cent allocation to general security accounts can be made at the start of the 2019-20 water year.

Water quality

• Recent BGA sampling at Hunter storages indicates a green alert is maintained at Glenbawn and Glennies Creek. Lostock storage is also at green alert.

Planned supply interruptions:

• Nil

Water availability weekly report 35

Hunter Dams forecast storage volume chance of exceedance 900 800 700 600 500 400 300

Storage Volume(GL) 200 100 0

WET 20% COE Median 50% COE DRY 80% COE Minimum Actual

Lostock Dam forecast storage volume chance of exceedance 25

20

15

10

Storage capacity(GL) 5

0

WET 20% COE Median 50% COE DRY 80% COE Minimum Actual

Water availability weekly report 36

7.3

Storage and release status

• Toonumbar Dam is at 68% of capacity and releasing 21 ML/d. Releases are forecast to remain steady for the week ahead.

Environmental water operations

• No current additional operations.

Water availability

• All licence categories have 100% availability.

Water quality

• Recent BGA sampling at Toonumbar indicates a red alert.

Toonumbar Dam forecast storage volume chance of exceedance 12

10

8

6

4

Storage capacity(GL) 2

0

WET 20% COE Median 50% COE DRY 80% COE Minimum Actual

Planned supply interruptions:

• Nil

Water availability weekly report 37

8. Rural Dam Levels

The following table shows the status of water supplies at 10 June 2019.

Cap- River Valley Current Status Comments Likeli- Allocations for 2018/19 acity Weekly hood % of Est change of fill active Active High Gen. Carry- Storage Dam, Nearest Town (GL) (GL) Supply Issues and cap- (GL) Security Security over @ spill acity 1/7/18

Border Rivers Glenlyon Dam, Stanthorpe 253 8% 21 -0 Releases ceased <20% 100% 2.7% 53% (Qld)Pindari Dam, Inverell 312 5% 17 -0 Minimum releases <20% 100% 2.7% 53% Gwydir Valley Copeton Dam, Inverell 1346 9% 125 -5 Environmental releases <5% 100% 0% 22% Namoi Valley Keepit Dam, Gunnedah 419 1% 4 0 Releases ceased <20% 100% 0% 19% Split Rock Dam, Manilla 394 2% 9 -0 Regulated releases <5% 100% 100% N/A Chaffey Dam, Tamworth 98 25% 24 -0 Regulated releases <50% 100% 38% N/A Macquarie Valley 5% 63 -2 Burrendong Dam, Wellington 1154 Regulated releases, <20% 100% 0% 52% restricted c/over

Windamere Dam, Mudgee 367 33% 120 -0 Regulated releases. <5% 100% 0% 102% BWT ceased Lachlan Valley Wyangala Dam, Cowra 1216 28% 335 -5 Regulated releases <20% 100% 0% 62% Carcoar Dam, Carcoar 36 22% 8 -0 Regulated releases 10% 100% 0% 67% Murrumbidgee Valley Burrinjuck Dam, Yass 1025 30% 309 0 Min Planned eWater 40% 95% 7% 22% Blowering Dam, Tumut 1604 39% 623 58 Min Planned eWater <10% 95% 7% 22% Murray Dartmouth, Mitta Mitta (Vic) 3837 63% 2404 -3 Minimum releases N/A N/A N/A N/A Hume Dam, Albury 2982 18% 525 48 Low releases <25% 97% 0% 31% Lower Darling Menindee Lakes, Broken Hill 1633 1% 15 -0 Releases ceased N/A 100% 0% 15% Hunter Valley Glenbawn Dam, Scone 750 52% 387 -1 Regulated releases 20% 100% 100% 21% Glennies Ck Dam, Singleton 282 54% 151 -1 Regulated releases 20% 100% 100% 21% Lostock Dam, Gresford 20 84% 17 -0 Regulated releases 100% 100% 100% N/A Coastal Area Toonumbar Dam, Kyogle 11 68% 7 -0 Regulated releases 100% 100% 100% N/A Brogo Dam, Bega 9 99% 9 -0 Regulated releases 100% 100% 65% N/A Total 17746 29.2% 5175 89

WaterNSW has water resources in Dartmouth, Hume and Glenlyon Dams. TWS = Town Water Supplies

1 Gigalitre (GL) = 1,000 Megalitres (ML) 1 ML = 1,000,000 litres

waternsw.com.au

More information

Subscribe to our customer information (weekly water availability reports, e-newsletters, etc.) at waternsw.com.au/subscribe.

Water availability weekly report 39