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

Wyangala Drought Inflows for 36 Months Starting in August Aug 1979 - Jul 1982 Aug 2001 - Jul 2004 Aug 2007 - Jul 2010 800 Aug 2017 - Sept 2019 (26 months) Drought of Record 700 600 Cumulative Inflows in GL 500 400 145 GL Deficit 300 200 100 0 0 5 10 15 20 25 30 35 40 No of Months • 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)

Restricted to 57% of GS balances in 2019-20 was based on pre-2004 DOR starting on 1 July 2019 IRG 3 – Drought Ops IRG 2 - Normal ops + saving WaterNSW

Water Balance for 57% accessibility – resource assessment 1 July 2019 Resource Distribution July 2019 - June 2020 July 2020 - May 2021 Storage Evap 30 24 Losses Essen Req 184 125 53% GS Env water 40 GS Irrig water 44 Conveyance 7 2 Town/S&D/HS 48 26 Allocations Planned Env 10 10 29% 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 0 Dam inflows 44 93 Trib Inflows 18 68 390 188

Comparison of current inflows

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

Lachlan Total Sales Vs Essential Req Envelop curve ER(GL)=14%*reg.sales(in GL)+180GL 350 98/99 300 250 2012/13 2010/11 2018/19 2001/02 96/97 2015/16 2000/01 94/95 Essential Req (GL) 2017/18 99/2000 2013/14 200 95/96 Base 2002/03 97/98 2014/15 2006/07 2019-20 150 Under Drought Contingency Plan 2008/09 2020-21 2016/17 2005/06 2003/04 floods 2004/05 2007/08 100 2009/10 Under Critical Water Ops 50 0 0 50 100 150 200 250 300 350 400 450 500 Total Sales (GL) WaterNSW

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 on 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 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 Association Inc. Condobolin 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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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

WaterNSW 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 7500 5000 2500 0 412023 ISLAND CK FAIRHOLME 141.00 Discharge (ML/d) CP 3000 2500 2000 1500 1000 500 0 412016 WALLAMUNDRY O-ISLAND 141.00 Discharge (ML/d) CP 500 400 300 200 100 0 412188 NERATHONG @ NERATHON 141.00 Discharge (ML/d) CP 75 50 25 0 412046 WALLAROI WORRONGORRA 141.00 Discharge (ML/d) CP 2500 2000 1500 1000 500 0 2003/04 2004/05 2005/06 2006/07 2007/08 2008/09 2009/10

WaterNSW 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 500 400 300 200 100 0 412023 ISLAND CK FAIRHOLME 141.00 Discharge (ML/d) CP 500 400 300 200 100 0 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

Google map with structures. WaterNSW 25

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