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Sydney: Supporting information

For the water account period 01 July 2022 - 30 June 2023

  • Total annual rainfall during the 2022-23 was above average for the third consecutive year, contributing to high runoff and storage inflows across the region.
  • Total storage volumes decreased by three percentage points during the 2022-23 year to finish at 95% full by 30 June 2023.
  • 2% of surface water allocations and 4% of groundwater allocations were taken in 2022-23.

Schematic representation of the Sydney region. In 2022-23, runoff was 83% more than average. Storage volumes on 30 June 2023 were 95% full, 2% less as the previous year. 74% of the total surface water accessible (676 GL) was taken. 4% of the total groundwater accessible (89 GL) was taken.

For further information on the region's water accounting statements scroll down this page or click on the links below:

 

Water assets

Cataract Dam, Sydney region (WaterNSW © 2012)

 

  • Total water asset volumes in the region at 30 June 2023 was 2,641 GL, of which, more than 99% was water held in surface water storages. The remaining amount was water held in rivers.
  • There are no groundwater or urban water assets in the Sydney region.

 

Table S1 Accessible storage volume in the Sydney region over the past six water accounting periods ending 30 June
Surface water 2023 2022 2021 2020 2019 2018
Avon 122,075 144,168 140,529 124,100 76,913 97,350
Cataract 66,107 83,657 78,668 69,463 28,039 40,861
Cordeaux 77,935 92,049 92,603 69,184 38,291 44,813
Fitzroy Falls 6,980 6,667 9,815 8,256 8,158 4,526
Greaves Creek 298 299 259 211 132 154
Lake Medlow 173 103 123 131 140 158
Lower Cascade 250 298 235 189 216 183
Middle Cascade 105 167 167 112 112 110
Nepean 53,312 65,775 63,634 44,298 31,328 41,077
Prospect 30,622 30,649 32,337 29,295 31,366 29,972
Tallowa 82,018 84,661 85,342 87,541 82,864 79,336
Upper Cascade 1,756 1,328 1,642 1,738 1,207 1,358
Warragamba 1,994,507 2,005,517 1,974,580 1,666,906 1,077,055 1,448,744
Wingecarribee 22,615 20,119 20,934 19,728 13,796 15,819
Woronora 70,653 72,123 60,125 45,019 30,793 49,632
Accessible total 2,529,406 2,607,580 2,560,993 2,166,171 1,420,410 1,854,093
Dead storage 108,430 108,430 108,430 108,430 108,430 108,430
Total storage 2,637,836 2,716,010 2,669,423 2,274,601 1,528,840 1,962,523
Total capacity 2,766,470 2,766,470 2,766,470 2,766,470 2,766,470 2,766,470
% full 95.4% 98.2% 96.5% 82.2% 55.3% 70,9%

 

  • Storage volume decreased from 98.2% full on 30 June 2022 to 95.4% full on 30 June 2023 - a decrease of 2.8%.
  • Water in Lake Burragorang (which is formed by Warragamba Dam) makes up more than 75% of the region's total surface water storage.

 


Figure S2 Percentage-full volume on 30 June 2023 for each storage and total storage volume from 2009-2023 (inset)

  • Storage volume fluctuated between 95% and 105% full during the first six months of the 2022-23 year (July to December 2022), following the region's eighth-wettest spring on record.
  • An East Coast Low during the first week of July 2022 resulted in storages rising to 106% full, and remained near or above 100% through to November, following rainfall throughout spring.
  • Following low rainfall during December 2022, storages dropped to 96% and remained stable through to the end of the 2022-23 year.
  • More detailed information on the individual storages within the region is available on the Bureau of Meteorology's Water Storage website.

 

Water liabilities

Coastline near Gerringong, Sydney region (Bureau of Meteorology © Merryn Coutts)

 

  • Water liabilities in the Sydney region refer to the volume of allocation remaining on licence entitlements at the end of the 2022-23 year.

 

Table S2 Opening and closing balance of surface water allocations for individual users in the Sydney region over the past six water accounting periods
Description 2023 2022 2021 2020 2019 2018
Opening balance at 01 July 0 0 0 0 0 0
add Allocation 178,510 179,393 159,390 159,389 159,389 159,389
less Allocated diversion 2,840 2,796 2,146 8,260 13,370 14,651
less Adjustment and forfeiture 175,670 176,597 157,244 151,129 146,019 144,738
Closing balance at 30 June 0 0 0 0 0 0

 

Table S3 Opening and closing balance of groundwater allocations for individual users in the Sydney region over the past six water accounting periods
Description 2023 2022 2021 2020 2019 2018
Opening balance at 1 July 0 0 0 0 0 0
add Allocation 89,193 86,158 84,534 83,623 76,954 -
less Allocated diversion 3,522 24,026 16,918 19,914 3,409 -
less Adjustment and forfeiture 85,670 62,132 67,616 63,709 73,545 -
Closing balance at 30 June 0 0 0 0 0 0

 

  • The water supply licences for the region have a water management year that ends on 30 June.
  • As the carryover cannot be quantified, the unused portion of the allocation is assumed to be forfeited and the allocation remaining at the end of the year is 0 ML in the Sydney region.
  • A more detailed description of water allocations in the Sydney region is given in the Water use section below.

 

Water flows

Hawkesbury River, Sydney region (istock © Leadinglights)

 

  • Total water inflows into the Sydney region was 14,262 GL, 32% less than last year.
  • Surface water inflows contributed 10,753 GL (75%) of the total water inflows. Runoff contributed to 97% of the total surface water inflows.
  • Groundwater inflows contributed 2,375 GL (17%) of the total water inflows. Recharge from landscape contributed to 98% of the total groundwater inflows.
  • Urban water inflows contributed 1,136 GL (8%) of the total water inflows. Wastewater collected contributed to 53% of the total urban water inflows.
  • Total water outflows from the Sydney region was 14,107 GL, 31% less than last year.
  • Surface water outflows contributed 12,967 GL (92%) of the total water outflows. Outflow contributed to 72% of the total surface water outflows.
  • Groundwater outflows contributed 4 GL (<1%) of the total water outflows. Allocated extraction to individual users contributed to 100% of the total groundwater outflows.
  • Urban water outflows contributed 1,137 GL (8%) of the total water outflows. Discharge to sea contributed to 40% of the total urban water outflows.
  • A more detailed breakdown of inflows and outflows is given in the Statement of Changes in Water Assets and Water Liabilities for the Sydney urban region.

 

Water availability

 

Table S4 Annual surface water available in the Sydney region over the past six water accounting periods ending 30 June
Surface water 2023 2022 2021 2020 2019 2018
Water availability 13,056,750 18,981,698 13,700,017 8,330,336 3,568,338 3,522,029
Water accessible 676,322 715,357 702,134 659,251 754,929 798,820
Water taken 500,652 538,760 544,890 508,122 608,910 654,082
% water accessible taken 74% 75% 78% 77% 81% 82%

 

  • Physical surface water availability is calculated as the sum of storage volumes at the start of the year (see Water assets) and estimated inflows into storages and rivers during the year.
  • During 2022-23, surface water availability in the Sydney region was above average for the third consecutive year, but was 31% less than the previous year.
  • Surface water accessible is calculated as the sum of surface water allocations and other statutory rights, plus carryover at the start of the year.
  • Water taken during the year is influenced by the physical water available. Typically, water taken from surface water resources is lower than water availability and water accessible.
  • The decrease in physical surface water availability resulted in a decrease of water accessible and water taken across the region.

 

Water use

Wollongong Water Recycling Plant, Sydney region (Sydney Water Corporation © 2010)

 

Consumptive use

 

Table S5 Surface water taken for consumptive use in the Sydney region over the past six water accounting periods ending 30 June
Surface water 2023 2022 2021 2020 2019 2018
Individual users 2,840 2,796 2,146 8,260 13,370 14,651
Urban system 465,312 503,707 510,487 467,605 563,283 607,174
Statutory rights 32,500 32,257 32,257 32,257 32,257 32,257
Total 500,652 538,760 544,890 508,122 608,910 654,082

 

Table S6 Groundwater taken for consumptive use in the Sydney region over the past six water accounting periods ending 30 June
Groundwater 2023 2022 2021 2020 2019 2018
Individual users 3,522 24,026 16,918 19,914 3,409 -
Total 3,522 24,026 16,918 19,914 3,409 -

 

  • Water taken from surface water and groundwater resources for consumptive use was 504,174 ML, 10% less than last year.
  • Total surface water diverted in the region was 500,652 ML, about 7% less than last year.
  • Around 93% of the total surface water diverted was for urban system supply, almost entirely to the Sydney Water Corporation. Inter-region users under a statutory rights took slightly less than 7% of the total surface water diverted, while less than 1% was for individual users (comprising allocated and non-allocated diversions).
  • Total groundwater extracted in the region was 3,522 ML, 85% less than last year, all of which was for individual users. This was the lowest amount of groundwater extracted from the region since the 2018-19 period.

 

Allocations and diversions

 

Table S7 Surface water allocations and diversions for individual users in the Sydney region over the past six water accounting periods ending 30 June
Surface water 2023 2022 2021 2020 2019 2018
Individual users
Carryover 0 0 0 0 0 0
Allocated announcements 178,510 179,393 159,390 159,389 159,389 159,389
Allocated diversions 2,840 2,796 2,146 8,260 13,370 14,651
% used 2% 2% 1% 5% 8% 9%

 

  • In 2022-23, total surface water allocation was 178,510 ML, of which 2% of the allocated surface water was taken, all for individual users.
  • Total allocations for individual users were slightly less than last year, but 4% above the long-term average.
  • Despite the high allocations, total diversions were similar last year, but remained low due to favourable wet climate conditions across the region over the past few years.

 

Table S8 Groundwater allocations and extractions for individual users in the Sydney region over the past six water accounting periods ending 30 June
Groundwater 2023 2022 2021 2020 2019 2018
Individual users
Carryover 0 0 0 0 0 -
Allocated announcements 89,193 86,158 84,534 83,623 76,954 -
Allocated extractions 3,522 24,026 16,918 19,914 3,409 -
% used 4% 28% 20% 24% 4% -

 

  • In 2022-23, total groundwater allocation was 89,193 ML, of which, 4% of the allocated groundwater was taken, all for private and commercial use.
  • Total groundwater allocations for individual users was slightly more than last year, making it the highest in the five years of available data.
  • Despite the high allocations, total groundwater extractions for individual users were 85% less than last year, and well below the long-term average, reflecting the lack of demand for groundwater resources.

 

Urban supply system

 

Table S9 Water sources used in Sydney's urban supply system over the past six water accounting periods ending 30 June
Water sources 2023 2022 2021 2020 2019 2018
Surface water 461,612 501,523 509,116 464,608 556,608 597,959
Inter-region 3,700 2,184 1,371 2,997 6,675 9,215
Desalinated water 67,996 22,480 19,609 71,147 7,793 0
Total urban water supplied 533,308 526,187 530,096 538,752 571,076 607,174

 

  • Total inflow to the urban supply system was 533,308 ML, slightly more than last year.
  • Around 87% of the total urban supply was sourced from surface water storages, slightly less than last year.
  • Desalinated water made up roughly 13% of the total urban supply, while inter-region inflows made up the remaining amount of urban water supplied.
  • The contribution of desalinated water to the urban supply system tripled from the previous year, and was the highest since 2010-11.
  • For more information on the use of desalinated water for the Sydney region, please visit Sydney's Desalination Plant webpage.