National Water Account 2020

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Key findings

Climate and water

Water Accounting Statements

Supporting information

Region description

Sydney: Supporting information

Water assets

• Water asset volumes in the region at 30 June 2020 were 2,195 GL, more than 99% of which is water held in storages. The remaining amount is water held in rivers.

Figure S1 Total storage volume in the region at 30 June 2020 compared with the previous 10 years

• Storage volumes increased from 52% full at 30 June 2019 to 79% full at 30 June 2020, the first annual increase in storage in four years.
• Despite below-average annual rainfall in 2019–20, the increase in storage volume was influenced by high storage inflows following heavy rainfall in early-February 2020.
• Water in Lake Burragorang (which is formed by Warragamba Dam) makes up more than 70% of the region's total surface water storage.

Figure S2 Percentage-full volume on 30 June 2020 for each storage and total storage volume from 2013–2020 (inset)

• In early February 2020 storage levels had dropped to 43% full, the lowest in more than 10 years.
• High rainfall associated with a coastal trough that crossed the region in February 2020 resulted in a large rise in storage levels. Storage volume almost doubled in 10 days between 8–18 February 2020. This was the first significant rise in storage since June 2016.
• Level 2 water restrictions were introduced in December 2019 to reduce pressure on surface water supply. These restrictions were lowered to Level 1 on 1 March 2020 following the high rainfall in February (see Water restrictions).
• More detailed information on the individual storages within the region is available on the Bureau of Meteorology's Water Storage website.

Water liabilities

• Water liabilities in the Sydney region refer to the volume of allocation remaining on licence entitlements at the end of the 2019–20 year.

• The water supply licences for the region have a water management year that ends on 30 June. The portion of water allocation that has not been abstracted at the end of the water year is either forfeited or is carried over into the next water year.
• 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 was 0 ML.
• A more detailed description of water allocations in the Sydney region is given in the Water use section below.

Water flows

Figure S3 Water inflows and outflows for the region's water stores and systems during the 2019–20 year

• Total surface water flows into the region's storages was estimated to be around 4,865 GL. The key item contributing to surface water inflows was runoff, which made up more than 95% of the total surface water inflows.
• Runoff was lower than average (based on modelled data from 1971–2020), primarily due to the very poor rainfall across the region during the latter half of 2019.
• A key item contributing to surface water outflows from the region's storages was river outflow, which made up more than two thirds of the total surface water outflows. River outflow was higher than average, largely due to heavy rainfall associated with the coastal trough that crossed the region in February 2020.
• Water taken from surface water and groundwater resources for consumptive use was 528 GL, less than 10% of the total outflow (see Water use section below).

Water use

Figure S4 Water taken for consumptive use in the Sydney region in 2019–20

• Total surface water diverted in the region was 508,122 ML.
• 92% of the total diversion was for urban supply, almost entirely to the Sydney Water Corporation.
• 2% of the total diversion was for individual users under an allocation; 6% was for individual users under a statutory right.
• Total groundwater extracted in the region was 19,914 ML, all of which was for individual users.

Figure S5 Surface water allocations and diversions in the Sydney region for the years ending 30 June, from 2012–2020

• In 2019–20, total surface water allocation was 1,200 GL, mostly for urban system supply. 40% of the allocated surface water was taken.
• Diversions to the urban system were the lowest since 2011–12. The lower surface water supply was influenced by the Sydney Water Corporation opting to reduce pressure on its surface water resources during the summer months and increase its reliance on desalinated water to meet urban demand (see Water restrictions for more detail).
• Total groundwater allocation was 84 GL, mostly for irrigation or industrial purposes. 24% of the allocated groundwater was used.

Urban system supply

Figure S6 Water sources used in the Sydney region's urban supply system during the 2019–20 year compared with the previous nine years

• Total inflow to the water supply system was 538,752 ML, around 6% less than last year.
• Surface water diversion from the region's storages made up 87% of the urban water supply.
• Desalinated water made up 13% of urban supply, the highest contribution since 2010–11. The desalination plant commenced operation in January 2019 when WaterNSW's total operating storage capacity dropped below 60% and operated at full capacity between December 2019–February 2020 when Level 2 water restrictions were in place (see Water restrictions).

Water restrictions

• Sydney Water Corporation introduced temporary Level 1 restrictions in June 2019, which govern how water can be used on gardens and lawns and for pool filling and car washing.
• Level 2 water restrictions were introduced in December 2019 and Sydney's desalination plant was operating at full capacity to reduce pressure on surface water supply. Water restrictions were lowered to Level 1 on 1 March 2020 following the high rainfall in February.
• For more information, refer to the Bureau of Meteorology's Water Restrictions website.

Cultural and environmental water

Cultural benefit

• Cultural water values within the region are closely aligned with environmental water outcomes.
• More information on cultural water requirements are provided in the Cultural water management section in the 'Region description'.

Environmental benefit

• Provisions to protect the environmental values of water systems are defined in the region's water sharing plans.
• Each year, environmental flow releases are made at various river locations across the region.

Figure S7 Surface water environmental flow releases in 2019–20

• In 2019–20, environmental flow releases were made at 11 river locations throughout the region. The total volume released was 180 GL.
• Improved surface water availability across the region in the first half of 2020 meant the total volume released was much higher compared to the last two years.
• The largest environmental release, representing more than two thirds of the total, occurred in the Shoalhaven River below Tallowa Dam (Lake Yarrunga).