2019- 20 Mid-Lachlan Creeks Meeting Condobolin 5 November 2019 - - PowerPoint PPT Presentation

Lachlan River Operations 2019- 20

Mid-Lachlan Creeks Meeting Condobolin 5 November 2019

• Aug 2017 – Sept 2019 (26 months) actual dam inflows = 253 GL
• Aug – Sept 26 months pre 2004 DOR inflows = 400 GL (year 2003)
• Aug – Sept 26 months millennium DOR inflows = 201 GL (year 2009)

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 - Sept 2019 (26 months) Drought of Record

145 GL Deficit

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Restricted to 57% of GS balances in 2019-20 was based on pre-2004 DOR starting on 1 July 2019

IRG 2 - Normal ops + saving IRG 3 – Drought Ops

Water Balance for 57% accessibility – resource assessment 1 July 2019

Resource Distribution July 2019 - June 2020 July 2020 - May 2021 Storage Evap 30 24 Essen Req 184 125 GS Env water 40 GS Irrig water 44 Conveyance 7 2 Town/S&D/HS 48 26 Planned Env 10 10 end of yr dam vol 27 1 390 188 Resource Availability July 2019 - June 2020 July 2020 - May 2021 Dam volume start of yr 321 27 LC active volume 6 Dam inflows 44 93 Trib Inflows 18 68 390 188

Losses 53% Allocations 29%

Comparison of current inflows

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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

WaterNSW Base 94/95 95/96 96/97 97/98 98/99 99/2000 2000/01 2001/02 2002/03 2003/04 2004/05 2005/06 2006/07 2007/08 2009/10 2010/11 2012/13 2013/14 2014/15 2015/16 2016/17

floods

2017/18 2018/19 2019-20 2020-21

50 100 150 200 250 300 350 50 100 150 200 250 300 350 400 450 500 Essential Req (GL) Total Sales (GL)

Lachlan Total Sales Vs Essential Req

Envelop curve ER(GL)=14%*reg.sales(in GL)+180GL

2008/09

Under Drought Contingency Plan Under Critical Water Ops

Drought Contingency Measures – Lessons from millennium drought

• Cutdown regulated sections to reduce

transmission losses

• Take Lake Cargelligo offline to reduce

evaporation losses

• Control inefficiencies in extraction of BLR
• Reduction to access to GS and HS

allocations

Drought contingency measures/potential savings

• Additional restrictions on general security carryover

– Additional 10% restrict’n saves = 15 GL

• Suspend the Lachlan river end of system flow

– Approx delivery 16 – 18 GL, saving 2 – 6 GL

• Cease top-up flows to Lake Cargelligo

– Approx evap 15 - 20 GL, From1 Jan=10 GL, 1 Mar=4 GL

• Restrict’n on BLR and domestic & stock use
• Pulsed releases to Booberoi Creek

– Appx delivery 12 GL, saving 9 GL (07-08) to 6 GL (08-09)

• Deliver flows in the Wallamundry Creek system

down one creek rather than three

• Reconsider the use of the water quality allowance

– Allocated 20 GL, Res Assess 10GL, used in 18-19 = 5 GL

Potential drought response works

• Restoration of old channels around Lake

Cargelligo and new channels to deliver BLR

• New block banks below Booligal to hold water

for BLR between flows

• Mapping of fish refugia
• Aerators in weir and river pools to manage WQ.

Aerators in Wyangala Dam

• Desilting Booberoi Ck (one mile) for efficiency
• Flow regulators at Wallamundry offtake and

Lachlan arm at Torriganny Ck

Security of Town Water Supply Lachlan ceased to flow

• Cowra – restricted town water secured from

alternate sources

– Last major town to run out of water from Wyangala dam – Critical need: level 6 water restrictions ~ 4 ML/d – Infiltration gallery at low river level possibly 1.4 ML/d – 1937 river well (7m deep) possibly 1 to 2 ML/d – 3.7 ML/d from Central Tablelands Water dependent

• n Lake Rowlands storage level

– Investigating groundwater

• Billimari - 2 ML/d & 24 km pipeline
• A bore closer to Cowra ? – impact on existing bores

– Longer term – pipeline from Wyangala Dam.

Security of Town Water Supply Lachlan ceased to flow

• Parkes - restricted town water secured from

alternate sources

– Multiple sources, own dams (effectively empty now), river pump, 8 bores (shared with mine) – Bores bottomed out last year at 60m, pumps can go deeper. – Decline in monitoring bores –minimal recharge since Millennium Drought – Looking for more GW, and shared infrastructure with other councils (pipe networks)

Security of Town Water Supply Lachlan ceased to flow

• Forbes - restricted town water secured from

alternate sources

– River plus 3 bores – Upgrading Water Treatment Plant – Bores can supply ~75% of peak day demand, therefore should satisfy water restricted demand. – Concerned about other bores and drawdown. – Plans to duplicate pipeline from bores – Investigating more bores – closer to Parkes borefield – potential to link together – Need additional GW entitlement

Security of Town Water Supply Lachlan ceased to flow

• Lachlan Shire Council – require emergency

works implemented to secure restricted town water from alternate sources

– L. Cargelligo – secure with bore plus lake. Need more GW allocation. – Upgraded plant has improved, and reinstalled pump in Lake – Condobolin – Drought project part funded, may need new plant – 25 km pipeline needed to connect bore field

Security of Town Water Supply when Lachlan ceased to flow

• Small towns and villages rely on Lachlan

River

– Ootha – water carting – Derewong – water carting – Eubalong and Eubalong West – water carting – Oxley – water carting – Ivanhoe - GW – Hillston - GW – Booligal - GW

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

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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 (%)

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HYPLOT V133 Output 04/11/2019

Period 7 Year 01/07/2003 to 01/07/2010 2003-10 412036 LACHLAN JEMALONG WR 141.00 Discharge (ML/d) CP 412023 ISLAND CK FAIRHOLME 141.00 Discharge (ML/d) CP 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 2500 5000 7500 500 1000 1500 2000 2500 3000 100 200 300 400 500 25 50 75 500 1000 1500 2000 2500 2003/04 2004/05 2005/06 2006/07 2007/08 2008/09 2009/10

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HYPLOT V133 Output 04/11/2019

Period 7 Year 01/07/2003 to 01/07/2010 2003-10 412036 LACHLAN JEMALONG WR 141.00 Discharge (ML/d) CP 412023 ISLAND CK FAIRHOLME 141.00 Discharge (ML/d) CP 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 100 200 300 400 500 100 200 300 400 500 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

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Google map with structures.

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• End of Presentation