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

Recent Rainfall 10-2-20 24hrs 9-2-20 24hrs WaterNSW

Recent rain hydrographs WaterNSW HYPLOT V133 Output 17/02/2020 Period 9 Day 09/02/2020 to 18/02/2020 2020 412066 ABERCROMBIE HADLEY 2 141.00 Discharge (ML/d) PROV 100000 80000 60000 40000 20000 0 41200209 ABERCROMBIE @ ABER#2 141.00 Discharge (ML/d) PROV 50000 40000 30000 20000 10000 WaterNSW 0 9 10 11 12 13 14 15 16 17

Recent rain hydrographs WaterNSW HYPLOT V133 Output 17/02/2020 Period 9 Day 09/02/2020 to 18/02/2020 2020 412065 LACHLAN @ NARRAWA 141.00 Discharge (ML/d) PROV 20000 16000 12000 8000 4000 0 412050 CROOKWELL NARRAWA N. 141.00 Discharge (ML/d) PROV 150 100 50 0 412027 LACHLAN @ REIDS FLAT 141.00 Discharge (ML/d) PROV 15000 10000 5000 WaterNSW 0 9 10 11 12 13 14 15 16 17

Recent rain hydrographs WaterNSW HYPLOT V133 Output 17/02/2020 Period 9 Day 09/02/2020 to 18/02/2020 2020 412067 LACHLAN D/S WYANGALA 141.00 Discharge (ML/d) PROV 1200 1000 800 600 400 200 412175 HOVELLS CK @ NO.2 141.00 Discharge (ML/d) PROV 1250 1000 750 500 250 0 412029 BOOROWA PROSSERS XNG 141.00 Discharge (ML/d) PROV 300 250 200 150 100 50 0 412002 LACHLAN R @ COWRA 141.00 Discharge (ML/d) PROV 1450 1200 950 700 450 WaterNSW 200 9 10 11 12 13 14 15 16 17

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

NSW temperatures 8 WaterNSW

Soil moisture deficiencies January 2020 WaterNSW 9

Comparison of Drought inflows Wyangala Drought Inflows for 36 Months Starting in August 800 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 700 600 Cumulative Inflows in GL 500 252 GL Deficit in 400 inflows 300 200 100 0 0 5 10 15 20 25 30 35 40 No of Months • Aug 2017 – Jan 2020 (30 months) actual dam inflows = 256 GL • Aug – Jan 30 months pre 2004 DOR inflows = 509 GL (year 1947) WaterNSW • Aug – Jan 30 months millennium DOR inflows = 259 GL (year 2005)

End January 2020 assessment 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 4.2% 1.6% WaterNSW

End January 2020 assessment WaterNSW

Comparison combined inflows – recent years 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 350 300 Combined Cumulative Inflows in GL 250 200 150 100 50 0

Wyangala Dam Behaviour during Millennium Drought 2003-2010 Wyangala Dam Storage Volume During Millennium Drought 2003 - 2010 450000 45% Wyangala Volume (ML) Wyangala Level (%) 400000 40% 350000 35% 300000 30% 250000 25% 200000 20% 150000 15% 100000 10% 50000 5% 0 0% 01-Jul-03 01-Jul-04 01-Jul-05 01-Jul-06 01-Jul-07 01-Jul-08 01-Jul-09 01-Jul-10 WaterNSW

Water Availability Sum of Sum of Sum of Sum of Sum of Sum of Allocation Allocation Share Account Available Sum of Carryover Assignments Assignments Sum of 7 Feb 2020 Component Balance Water AWD Vol In In Out Usage 10,954 7,942 7,894 10,954 - - - 3,000 DOMESTIC AND STOCK DOMESTIC AND STOCK 176 173 173 176 - - - 3 [DOMESTIC] DOMESTIC AND STOCK 1,599 1,429 1,429 1,599 - - - 168 [STOCK] 15,545 9,563 8,935 15,545 - - - 5,982 LOCAL WATER UTILITY REGULATED RIVER 17,911 0 0 6,960 - - - 6,960 (CONVEYANCE) REGULATED RIVER 469,309 51,630 12,839 - 83,441 12,831 21,768 22,848 (Irrigation GS) REGULATED RIVER 123,492 42,108 8,041 - 71,609 11,007 32,221 8,286 (Environment GS) REGULATED RIVER 24,952 12,664 11,794 21,709 - 21,764 11,825 18,973 (Irrigation HS) REGULATED RIVER 2,728 589 589 2,373 - 22,026 1,862 21,949 (Environment HS) 666,667 126,098 51,693 59,317 155,023 67,628 67,676 88,169 Grand Total

What Does it take to operate Lachlan River - Transmission and Operation Loss IRG stage 3 IRG stage 4 Millennium Drought Regulated Lachlan River Typical dry drought drought Transmission & Operations Losses year (GL) 2004-05 2006-07 2008-09 operations operations Main regulated river from dam to Lake 56 27 76 59 55 55 Cargelligo Weir Wallamundry/Wallaroi/Nerrathong 14 14 13 12 12 6 system 12 7 7 6 6 3 Replenishment flows into Booberoi Ck Flows to Lake Cargelligo through 5 3 3 3 3 emergency works for TWS & BLR 15 4 2 0 2 2 Losses in regulated Willandra Ck system 40 42 47 40 39 20 Losses LC Weir to Booligal 13 15 15 14 13 6 Target Flows required below Booligal Replenishment Flows into Willandra 9 5 0 0 0 0 Creek Replenishment Flows into Merrowie 9 0 0 0 0 0 Creek Replenishment Flows into 7 0 0 0 0 0 Merrimajeel/Muggabh Creek 5 0 0 0 0 0 Operational Surplus WaterNSW 180 118 163 135 130 95 Total

Flows during millennium drought WaterNSW HYPLOT V133 Output 19/02/2020 Period 7 Year 01/07/2003 to 01/07/2010 2003-10 412016 WALLAMUNDRY O-ISLAND 141.00 Discharge (ML/d) CP 100 80 60 40 20 0 412188 NERATHONG @ NERATHON 141.00 Discharge (ML/d) CP 100 80 60 40 20 0 412046 WALLAROI WORRONGORRA 141.00 Discharge (ML/d) CP 100 80 60 40 20 0 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 Entitle Name of the Scheme/ River Section Licence Category ment Representative (ML) Neighbourhood Association 111 Domestic and Stock 28 Neighbourhood Association 353 Domestic and Stock 32 Wyangala Dam Carro Park Water Supply Pty Domestic and Stock 32 to Cowra Ltd. Lachlan Water Supply Pty Ltd. Domestic and Stock 72 Nanami to Grawlin Water Scheme Domestic and Stock 88 Cottons Weir South Gipps Water Users Domestic and Stock 112 Association Walloroi Creek Milby Water Users Association Domestic and Stock 120 Inc. Wallamundry Euglo Joint Water Supply Domestic and Stock 128 Creek Group Inc. Bundaburra Water Scheme Domestic and Stock 25.5 Potters Pipeline Inc. Domestic and Stock 36 Goobang Creek Murda Water Users Association Domestic and Stock 40 Inc. Wardry Water Users Domestic and Stock 160 Condobolin Association Inc. Weir to Mowabla Water Scheme Domestic and Stock 211 Booberoi Weir Yaddra Water Scheme Domestic and Stock 10 NSW Aboriginal Land Council Domestic and Stock 9 Lake Cargelligo Bogan Street Lane Pipeline Inc. Domestic and Stock 18 Storage [Domestic] Booligal to Noonamah Scheme Domestic and Stock 1691 Corrong

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

Climate Outlook

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