Lachlan River Operations 2019- 20 Lake Cargelligo 18 Feb 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
36 month rainfall deficiency 7 WaterNSW
NSW temperatures 8 WaterNSW
Soil moisture deficiencies August 2019 WaterNSW 9
Comparison of Drought inflows Wyangala Drought Inflows for 36 Months Starting in August Aug 1979 - Jul 1982 Aug 2001 - Jul 2004 Aug 2007 - Jul 2010 800 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
LC Storage by end of March 20 80% 70% 60% Storage Percent 50% Storage Forecast 40% 30% 20% 1-Jul 1-Aug 1-Sep 1-Oct 1-Nov 1-Dec 1-Jan 1-Feb 1-Mar WaterNSW
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
Supply Source Vs Resource Distribution End Jan 20
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
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 • 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
LC Work Approval Locations WaterNSW
LC Usage 2017-18 Orders Usage Lake Cargelligo Storage 100 149.6 DOMESTIC AND STOCK 0 0 DOMESTIC AND STOCK [DOMESTIC] 0 2.2 DOMESTIC AND STOCK [STOCK] 0 0 LOCAL WATER UTILITY 55 50.8 REGULATED RIVER (GENERAL SECURITY) 45 96.6 REGULATED RIVER (HIGH SECURITY) 0 0 2018-19 Orders Usage Lake Cargelligo Storage 21.5 45.1 DOMESTIC AND STOCK [STOCK] 0 0 LOCAL WATER UTILITY 0 0 REGULATED RIVER (GENERAL SECURITY) 15.5 43.4 REGULATED RIVER (HIGH SECURITY) 6 1.7 WaterNSW
LC Water Supply Emergency Works WaterNSW
WaterNSW
25% chance 17 Feb to 1 Mar 50% chance 17 Feb to 1 Mar WaterNSW
Climate Outlook
• End of Presentation
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