Namoi ROSCCo (River Operations Stakeholder Consultation Committee) - - PowerPoint PPT Presentation

23 July 2020

Namoi ROSCCo

(River Operations Stakeholder Consultation Committee)

WaterNSW

Namoi Valley Map

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WaterNSW

• Rainfall and climate
• Allocations and Usage
• Restrictions
• Supplementary access
• 14 media releases relating to restrictions and extraction in northern valleys alone

from 17 Jan to 25 Feb 2020

• https://www.waternsw.com.au/__data/assets/pdf_file/0009/145287/Operations-

Update-Namoi-1-July.pdf

• https://www.waternsw.com.au/__data/assets/pdf_file/0018/151641/191206-

Operations-Update-Upper-Namoi.pdf

• https://www.waternsw.com.au/about/newsroom/2020/324-temporary-pump-

restrictions-for-northern-valleys

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Part 1 - Overview of 2019/2020

WaterNSW 4

Rainfall – last 24 months

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Rainfall – last 12 months

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Temperature – last 12 months

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Rainfall – last 3 months

WaterNSW

https://waterregister.waternsw.com.au/water-register-frame

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2019/20 Water Availability

Upper Namoi

WaterNSW

2019/20 Water Availability

Lower Namoi

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WaterNSW

• The 2020 Northern Basin First Flush Event:
• Followed an extensive period of hot and dry conditions with record low rainfall and record low inflows
• Included significant inflows from across the Northern Basin including the Border, Moonie, Gwydir, Namoi, Culgoa,

Bokhara, Macquarie, Bogan and Warrego systems.

• Involved a large number of Temporary Water Restrictions being placed on extractions in the Northern Basin.
• Raised issues regarding communication and decision making processes.
• Resulted in the appointment of an Independent Panel to assess the management of the event

– https://www.industry.nsw.gov.au/water/allocations-availability/northern-basin-first-flush-assessment – Terms of Reference, consultation, Water User Reference Group – Final report with recommendations – end of August 2020

• Resulted in around 585 GL of inflow arriving into the Menindee Lakes system.

WaterNSW published regular Operations Updates throughout the event at https://www.waternsw.com.au/supply/regional-nsw/operations-updates A draft report is available at https://www.industry.nsw.gov.au/water/allocations-availability/northern-basin-first- flush-assessment A webinar will also be held on Monday 27 July from 1:00 to 2:30pm. Registration for the Webinar is required. 10

Northern Basin First Flush Event

WaterNSW

• 17 Jan - https://www.waternsw.com.au/about/newsroom/2020/324-temporary-

pump-restrictions-for-northern-valleys

• 26 Jan - https://www.waternsw.com.au/about/newsroom/2020/pump-restrictions-

lifted-for-peel-high-security-and-unregulated-use-on-mooki-and-quirindi-systems

• 31 Jan - https://www.waternsw.com.au/about/newsroom/2020/324-pump-

restrictions-extended-for-northern-valleys

• 7 Feb - https://www.waternsw.com.au/about/newsroom/2020/temporary-rule-

change-to-allow-some-stock-water-trade

• 7 Feb - https://www.waternsw.com.au/about/newsroom/2020/temporary-pump-

restriction-on-floodplain-harvesting

• 10 Feb - https://www.waternsw.com.au/about/newsroom/2020/approval-to-take-

under-temporary-water-restrictions-information

• 11 Feb - https://www.waternsw.com.au/about/newsroom/2020/approval-to-take-

under-temporary-water-restrictions-11-february

• 11 Feb - https://www.waternsw.com.au/about/newsroom/2020/324-orders-on-

floodplain-harvesting-in-the-northern-basin

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Media releases

WaterNSW

• 12 Feb - https://www.waternsw.com.au/about/newsroom/2020/amendment-to-

temporary-pump-restriction-on-floodplain-harvesting

• 12 Feb - https://www.waternsw.com.au/about/newsroom/2020/temporary-

water-restriction-northern-nsw-murray-darling-basin-yarraman-creek-12- february-2020

• 13 Feb - https://www.waternsw.com.au/about/newsroom/2020/temporary-

water-restrictions-on-river-and-overland-flows-in-the-northern-basin

• 14 Feb - https://www.waternsw.com.au/about/newsroom/2020/324-pump-

restrictions-extended-for-northern-valleys2

• 21 Feb - https://www.waternsw.com.au/about/newsroom/2020/barwon-darling-

flows-a-blessing-for-towns,-farmers

• 25 Feb - https://www.waternsw.com.au/about/newsroom/2020/324-pump-

restrictions-lifted-in-namoi,-border-rivers

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Media releases

WaterNSW 13

Supplementary Access 19/20

Event Volume calculations ML

Narrabri Creek @ Narrabri 9/02/2020 to 7/03/2020 117422 Brigalow Creek inflow 9/02/2020 to 7/03/2020 2653 Total Flow 120075

Total Available Share

120075 less volume proir to trigger 94 less volume to fill weirs less volume to meet Pian Creek repenishment 4700 D/S orders/requirements (riparian flows) 1783 less volume after cease 164 Available flow to be shared 113334 50% Consumptive share 56667 Volume Announced A 2452 Volume Announced B Total Volume Announced 2452 Total Supplementary extracted 2452 Over Pumping debited to other accounts Total Supplementary Pumping 2452 Percentage announced 2.2% Percentage extracted 2.2% Notes: 10 hours access for A Class Narrabri to Weeta. 48 hours access for A class Weeta to Walgett. No B class access. Up to 50% supplementary volume able to be extracted 1 November to 30 June Restrictions applied to event.

Lower Namoi Supplementary Event 1 2019/2020

WaterNSW

Supplementary Access 19/20

Event Volume calculations ML

Bugilbone gauged inflow 12 March to 14 March 3016 Total Flow 3016

Total Available Share

3016 less volume proir to trigger less volume to fill weirs less volume to meet Pian Creek repenishment D/S orders/requirements (riparian flows) 362 less volume after cease Available flow to be shared 2654 50% Consumptive share 1327 Volume Announced A 1388 Volume Announced B Total Volume Announced 1388 Total Supplementary extracted 1388 Over Pumping debited to other accounts Total Supplementary Pumping 1388 Percentage announced 52.3% Percentage extracted 52.3% Notes: 8 hours access for A Class - Weeta to Walgett. No B class access. Up to 50% supplementary volume able to be extracted 1 November to 30 June

Lower Namoi Supplementary Event 2 2019/2020

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WaterNSW 15

Supplementary Access 19/20

Event Volume calculations ML

Narrabri Creek @ Narrabri 8 April to 17 April 7382 Ungauged inflow (positive AUD Weeta to Bullawa 12 to 16 April) 1437 Brigalow Creek inflow - gauged flow 11 April to 13 April 399 Total Flow 9218

Total Available Share

9218 less volume prior to trigger 121 less volume to fill weirs less volume to meet Pian Creek repenishment D/S orders/requirements (incl riparian flows) less volume after cease 286 Available flow to be shared 8811 50% Consumptive share 4406 Volume Announced A 4074 Volume Announced B Total Volume Announced 4074 Total Supplementary extracted 4074 Over Pumping debited to other accounts Total Supplementary Pumping 4074 Percentage announced 46.2% Percentage extracted 46.2% Notes: Total 45 hours access for all A Class No B class access. Up to 50% supplementary volume able to be extracted 1 November to 30 June

Lower Namoi Supplementary Event 3 2019/2020

WaterNSW 16

Supplementary Access 19/20

Event Volume calculations ML

Bugilbone gauged inflow 17 to 18 April 371 Total Flow 371

Total Available Share

371 less volume proir to trigger less volume to fill weirs less volume to meet Pian Creek repenishment D/S orders/requirements (riparian flows) less volume after cease Available flow to be shared 371 50% Consumptive share 186 Volume Announced A 195 Volume Announced B Total Volume Announced 195 Total Supplementary extracted 195 Over Pumping debited to other accounts Total Supplementary Pumping 195 Percentage announced 52.6% Percentage extracted 52.6% Notes: 20 hours access for A Class - Bugilbone to Walgett. No B class access. Up to 50% supplementary volume able to be extracted 1 November to 30 June

Lower Namoi Supplementary Event 4 2019/2020

WaterNSW

• Drought Update
• Drought Map
• Inflows
• WNSW Water Insights Portal

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Part 2 - Current Situation

WaterNSW

WaterNSW

Regional drought map

WaterNSW

• Split Rock Dam inflows since Jan 2020

to end June 2020 have been 16GL

• Just above 50th%ile of 12.7GL
• Split Rock Dam inflows since July 2018

to end June 2020 have been 20GL just above minimum of 11GL (95th%ile is 24GL)

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Namoi Valley Inflows

WaterNSW

• Keepit Dam inflows since Jan 2020 to

end June 2020 have been 61GL

• In line with 50th%ile inflows of 61.5GL
• Downstream tributary flow has been

approximately 105GL.

• Keepit Dam inflows since July 2018 to

end June 2020 have been 66.5GL(excluding BWT) just above minimum of 53GL

• Downstream tributary flow for the 24

month period has been approximately 116GL.

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Namoi Valley Inflows

Water Insights

• Storage levels
• Inflows
• Releases
• Compare

multiple years

• Allocations
• Outlook
• more

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WaterNSW 23

https://waterinsights.waternsw.com.au/11986-lower-namoi-regulated-river/updates

Keepit & Split Rock Dam

WaterNSW 24

Allocations (screen shots from WaterInsights)

WaterNSW

• Storage Forecasts
• Climate outlook
• Allocations
• Operations
• Projects

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Part 3 – Outlook for 2020/2021

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Storage Forecast

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Storage Forecast

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Rainfall outlook August to October

WaterNSW 29

Rainfall outlook September to November

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Operations 2020/2021

River section Licence category Type of restriction Period of applicability Method of placing water order

Upper Namoi (Split Rock Dam to upstream of Keepit) High Security General Security Stock & Domestic Local Water Utility Tributary inflows will continue to be utilised where possible. Minimal dam releases will be made to provide access to account water. A water order is still required to be placed and needs to be approved by WaterNSW. Until further notice Via iWAS or the customer help desk Confirmation of water order from WaterNSW is required. Lower Namoi (downstream of Keepit Dam to Walgett) High Security General Security Stock & Domestic Local Water Utility Tributary inflows will continue to be utilised where possible. No Dam releases will be made to supply orders

• r the Pian Ck replenishment flow

however in order to provide for some deliveries, a block release strategy may be considered with favourable downstream conditions Access will be made available from tributary inflows where possible. A water order is still required to be placed and needs to be approved by WaterNSW. Until further notice Via iWAS or the customer help desk Confirmation of water order from WaterNSW is required.

WaterNSW

▪ Potential Block release: S&D/riparian/replenishment/general security for Lower Namoi ▪ Namoi @ U/S Walgett gauge – impacted by back water

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Discussion Points

WaterNSW

• $2000 Water Carting rebate

available through Service NSW

• https://www.service.nsw.gov.au

/transaction/apply-water- carting-rebate

• helps with the cost of carting

water or installing water tanks and pipes

• to help secure domestic water

needs

• available in the Upper Namoi

downstream of Manilla and in the Lower Namoi downstream

• f Keepit

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Water Carting Rebate

WaterNSW 33

GROUNDWATER RESOURCE STATUS INFORMATION

• Upper and Lower

Namoi Alluvium Groundwater Sources

• This presentation is an initiative by

WaterNSW to gather groundwater resource status information for various groundwater sources in NSW

Part 4 – Groundwater (a snapshot)

WaterNSW

• The surface geology of the Namoi

Catchment comprises five main units namely: ➢ Palaeozoic New England Fold Belt ➢ Palaeozoic to Mesozoic Gunnedah Basin ➢ Mesozoic Great Artesian Basin (GAB) ➢ Cenozoic unconsolidated sediments ➢ Cenozoic extrusive volcanics ➢

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Geology

WaterNSW 35

Cross Section Upper Namoi Alluvium

Gunnedah-Oxley Basin MDB, GAB and New England Fold Belt

WaterNSW

• Upper Namoi Alluvium

➢ Groundwater salinity across the Upper Namoi Alluvium is generally less than 1,500 μS/cm ➢ Some areas of higher salinity up to 20,000 μS/cm ➢ Upper Namoi Zone identified increasing depth salinity ➢ The shallow alluvium salinity ranges between approximately 6,000-18,000 μS/cm ➢ The deeper aquifer ranged between 600 and 14,000 μS/cm 36

Groundwater Quality

Lower Namoi Alluvium

➢ Groundwater salinity in the main body of the Lower Namoi Alluvium is generally less than 1,500 μS/cm ➢ Salinity increases with distance from the recharge areas to more than 20,000 μS/cm in the southern and western margins ➢ At the western margin of the Lower Namoi Alluvium, deeper low salinity groundwater is overlain by a highly saline water table aquifer ➢ Lack of river recharge in this area has the potential for deep aquifer salinization due to vertical leakage

WaterNSW

• correlation between water level response and extraction pattern

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Groundwater Extraction and Winter Recovery Level

5 10 15 20 25 30 35 20 40 60 80 100 120 140

2006-2007 2007-2008 2008-2009 2009-2010 2010-2011 2011-2012 2012-2013 2013-2014 2014-2015 2015-2016 2016-2017 2017-2018 2018-2019 2019-2020

Winter Recovery Level (m) Annual Groundwater Extraction (GL) Water Year

LOWER NAMOI ALLUVIUM GROUNDWATER SOURCE Groundwater Extractions and Recovered Water Level 2006-2020

GW Extraction Winter Recovery Level 2006-2020 GW021266 Screen Depth 107.3-113.4 mbgl

No data

WaterNSW

Visit the website at:

waternsw.com.au/drought

For information including water availability reports and drought reports go to:

https://www.waternsw.com.au/supply/drought- information/regional-nsw

Call us on:

1300 662 077

Subscribe at:

waternsw.com.au/subscribe

For weekly customer drought updates and more information

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To keep updated

WaterNSW

End of Presentation