2019- 20 Mid-Lachlan Creeks Meeting Condobolin 19 February 2020 - - PowerPoint PPT Presentation

Lachlan River Operations 2019- 20

Mid-Lachlan Creeks Meeting Condobolin 19 February 2020

WaterNSW

Recent Rainfall

10-2-20 24hrs 9-2-20 24hrs

WaterNSW

Recent rain hydrographs

WaterNSW

Period 9 Day 09/02/2020 to 18/02/2020 2020 412066 ABERCROMBIE HADLEY 2 141.00 Discharge (ML/d) PROV 41200209 ABERCROMBIE @ ABER#2 141.00 Discharge (ML/d) PROV 20000 40000 60000 80000 100000 10000 20000 30000 40000 50000 9 10 11 12 13 14 15 16 17

WaterNSW

Recent rain hydrographs

WaterNSW

Period 9 Day 09/02/2020 to 18/02/2020 2020 412065 LACHLAN @ NARRAWA 141.00 Discharge (ML/d) PROV 412050 CROOKWELL NARRAWA N. 141.00 Discharge (ML/d) PROV 412027 LACHLAN @ REIDS FLAT 141.00 Discharge (ML/d) PROV 4000 8000 12000 16000 20000 50 100 150 5000 10000 15000 9 10 11 12 13 14 15 16 17

WaterNSW

Recent rain hydrographs

WaterNSW

Period 9 Day 09/02/2020 to 18/02/2020 2020 412067 LACHLAN D/S WYANGALA 141.00 Discharge (ML/d) PROV 412175 HOVELLS CK @ NO.2 141.00 Discharge (ML/d) PROV 412029 BOOROWA PROSSERS XNG 141.00 Discharge (ML/d) PROV 412002 LACHLAN R @ COWRA 141.00 Discharge (ML/d) PROV 200 400 600 800 1000 1200 250 500 750 1000 1250 50 100 150 200 250 300 200 450 700 950 1200 1450 9 10 11 12 13 14 15 16 17

WaterNSW

Current Storage Status

• Wyangala: as at 17/02/20
• Storage Volume: 155,032 ML
• Storage Percent: 12.7%, increase of 4.3% from 8.4% on 10 Feb
• System Inflows since 1July19 – 31 Jan 20: 9,700 ML
• System Inflows since 1 Feb 20 – 9 Feb 20: 4,000 ML (2 GL + 2 GL)
• System Inflows since 10 Feb 20 – 17 Feb: 58,000 ML (55 GL + 3 GL)
• Lake Cargelligo:
• Storage Volume: 23,898 ML (17 Feb 20)
• Storage Percent: 58.1%
• Projected Volume: 28,261 ML (1 March 20)
• Projected Percent: 72%

WaterNSW

22 month rainfall deficiency

WaterNSW

8

NSW temperatures

WaterNSW 9

Soil moisture deficiencies

January 2020

WaterNSW

Comparison of Drought inflows

• Aug 2017 – Jan 2020 (30 months) actual dam inflows = 256 GL
• Aug – Jan 30 months pre 2004 DOR inflows = 509 GL (year 1947)
• Aug – Jan 30 months millennium DOR inflows = 259 GL (year 2005)

100 200 300 400 500 600 700 800 5 10 15 20 25 30 35 40 Cumulative Inflows in GL No of Months

Wyangala Drought Inflows for 36 Months Starting in August

Aug 1979 - Jul 1982 Aug 2001 - Jul 2004 Aug 2007 - Jul 2010 Aug 2017 - Jan 2020 (30 months) Drought of Record Aug 1944 - Jul 1947

252 GL Deficit in inflows

WaterNSW

Assumptions:

• Zero inflows
• Water savings 15 GL in

2019-20

• 2020-21under IRG 3

Essential Requirements – 130GL

• GS under usage – 10 GL
• WQA – 1GL
• No S&D replenishment
• Lake Cargelligo Offline

March 2020

End January 2020 assessment

4.2% 1.6%

WaterNSW

End January 2020 assessment

Comparison combined inflows – recent years

50 100 150 200 250 300 350 Combined Cumulative Inflows in GL

Actual Combined Inflows Vs Minimum Combined Inflows starting July 2019

Pre 2004 Combined Inflows for 57% GS access Inflows from 1 July 19 2018-19 Combined Inflows 2017-18 Combined Inflows

WaterNSW

Wyangala Dam Behaviour during Millennium Drought 2003-2010

0% 5% 10% 15% 20% 25% 30% 35% 40% 45%

50000 100000 150000 200000 250000 300000 350000 400000 450000 01-Jul-03 01-Jul-04 01-Jul-05 01-Jul-06 01-Jul-07 01-Jul-08 01-Jul-09 01-Jul-10

Wyangala Dam Storage Volume During Millennium Drought 2003 - 2010

Wyangala Volume (ML) Wyangala Level (%)

Water Availability

7 Feb 2020 Sum of Share Component Sum of Account Balance Sum of Available Water Sum of AWD Vol Sum of Carryover In Sum of Allocation Assignments In Sum of Allocation Assignments Out Sum of Usage DOMESTIC AND STOCK

10,954 7,942 7,894 10,954 -

• 3,000

DOMESTIC AND STOCK [DOMESTIC]

176 173 173 176

• 3

DOMESTIC AND STOCK [STOCK]

1,599 1,429 1,429 1,599

• 168

LOCAL WATER UTILITY

15,545 9,563 8,935 15,545 -

• 5,982

REGULATED RIVER (CONVEYANCE)

17,911 6,960

• 6,960

REGULATED RIVER (Irrigation GS)

469,309 51,630 12,839

• 83,441

12,831 21,768 22,848

REGULATED RIVER (Environment GS)

123,492 42,108 8,041

• 71,609

11,007 32,221 8,286

REGULATED RIVER (Irrigation HS)

24,952 12,664 11,794 21,709 - 21,764 11,825 18,973

REGULATED RIVER (Environment HS)

2,728 589 589 2,373

• 22,026

1,862 21,949

Grand Total

666,667 126,098 51,693 59,317 155,023 67,628 67,676 88,169

WaterNSW

What Does it take to operate Lachlan River

• Transmission and Operation Loss

Regulated Lachlan River Transmission & Operations Losses Typical dry year (GL) Millennium Drought IRG stage 3 drought

• perations

IRG stage 4 drought

• perations

2004-05 2006-07 2008-09

Main regulated river from dam to Lake Cargelligo Weir

56 27 76 59 55 55

Wallamundry/Wallaroi/Nerrathong system

14 14 13 12 12 6

Replenishment flows into Booberoi Ck

12 7 7 6 6 3

Flows to Lake Cargelligo through emergency works for TWS & BLR

5 3 3 3 3

Losses in regulated Willandra Ck system

15 4 2 2 2

Losses LC Weir to Booligal

40 42 47 40 39 20

Target Flows required below Booligal

13 15 15 14 13 6

Replenishment Flows into Willandra Creek

9 5

Replenishment Flows into Merrowie Creek

9

Replenishment Flows into Merrimajeel/Muggabh Creek

7

Operational Surplus

5

Total

180 118 163 135 130 95

Flows during millennium drought

WaterNSW

Period 7 Year 01/07/2003 to 01/07/2010 2003-10 412016 WALLAMUNDRY O-ISLAND 141.00 Discharge (ML/d) CP 412188 NERATHONG @ NERATHON 141.00 Discharge (ML/d) CP 412046 WALLAROI WORRONGORRA 141.00 Discharge (ML/d) CP 20 40 60 80 100 20 40 60 80 100 20 40 60 80 100 2003/04 2004/05 2005/06 2006/07 2007/08 2008/09 2009/10

Drought Contingency Measures - Current

• Reduction to access - remaining GS (57%) and HS (87%) allocations
• Cutdown flows in regulated sections to minimise transmission losses (Willandra Creek)
• Reduced flows in regulated sections to minimise incremental losses (Wallamundry

System)

• Reduced End of System Targets
• Booberoi Creek flows assisted by delivery of environmental water
• Conservative use of WQA
• Take Lake Cargelligo offline – may be delayed to Sept 2020
• No delivery of S&D Replenishment from Wyangala

Drought Contingency Measures – Potential

• Further reduction to access remaining GS after 31 March 20
• After 31 March, normal delivery of remaining HS allocations to Condobolin,

but only critical human needs d/s of Condobolin

• Continue cease to flows in Willandra Creek
• Reduced flows in Wallamundry System, deliver flows in one of the creeks.
• Control inefficiencies in extraction of BLR
• Above measures and others will be discussed in ROSCCo next week

Supply Source Vs Resource Distribution

End Jan 20

Licenced Water Supply schemes

River Section Name of the Scheme/ Representative Licence Category Entitle ment (ML) Neighbourhood Association 111 Domestic and Stock 28 Neighbourhood Association 353 Domestic and Stock 32 Carro Park Water Supply Pty Ltd. Domestic and Stock 32 Wyangala Dam to Cowra Lachlan Water Supply Pty Ltd. Domestic and Stock 72 Nanami to Cottons Weir Grawlin Water Scheme Domestic and Stock 88 South Gipps Water Users Association Domestic and Stock 112 Walloroi Creek Milby Water Users Association Inc. Domestic and Stock 120 Wallamundry Creek Euglo Joint Water Supply Group Inc. Domestic and Stock 128 Bundaburra Water Scheme Domestic and Stock 25.5 Potters Pipeline Inc. Domestic and Stock 36 Goobang Creek Murda Water Users Association Inc. Domestic and Stock 40 Wardry Water Users Association Inc. Domestic and Stock 160 Mowabla Water Scheme Domestic and Stock 211 Yaddra Water Scheme Domestic and Stock 10 Condobolin Weir to Booberoi Weir NSW Aboriginal Land Council Domestic and Stock 9 Lake Cargelligo Storage Bogan Street Lane Pipeline Inc. Domestic and Stock [Domestic] 18 Booligal to Corrong Noonamah Scheme Domestic and Stock 1691

23

24

WaterNSW

25% chance 17 Feb to 1 Mar 50% chance 17 Feb to 1 Mar

Climate Outlook

• End of Presentation