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South East Queensland: Supporting information

  • Dry conditions contributed to low runoff and storage inflows across the region.
  • Storage volumes at 30 June 2021 were 62% full, marginally higher than the previous year.
  • 57% of the allocated water was taken in 2020–21, primarily for residential use.

Schematic representation of the South East Queensland region. In 2020–21, runoff was 10% less than average. Storage volumes at 30 June 2021 were 62% full, marginally higher than the previous year. 70% of the total surface water allocation (574 GL) was taken. 40% of the total groundwater allocation (28 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

Lake Perserverance, SEQ region (Bureau of Meteorology © Habibur Rahman)

 

  • Total water asset volumes in the region at 30 June 2021 were 1562 GL, around 98% of which is water held in storages. The remaining amount is water held in rivers and aquifers.

 

Bar graph of annual storage volume in the South East Queensland region at 30 June for the years 2010–2021. Accessible storage plus dead storage is plotted against the storage capacity to show percentage full at 30 June each year. Storages at 30 June 2021 were 62% full, marginally higher than the previous year. Since 2010, the highest end-of-year storage volume was in 2015 when storages were 95% full and the lowest was in 2020 when storages were 60% full. Since 2015, there has been a general decreasing trend in storage volume.
Figure S1 Total storage volume in the region at 30 June 2021 compared with the previous 11 years

 

  • Storage volumes increased marginally from 60% full at 30 June 2020 to 62% full at 30 June 2021.
  • Five storages (Wivenhoe, Somerset, Hinze, North Pine and Wyaralong) make up more than 80% of the region's total surface water storage.

 

Map of South East Queensland region showing the status of each storage at 30 June 2021. The storages are colour coded into ten categories of volume as a proportion of capacity. Storages located in the western inland part of the catchment were generally less full than storages in the east nearer to the coast. Atkinson, Clarendon, and Bill Gunn storages were less than 10% full. Wivenhoe, Cressbrook Creek, Perseverance, and Moogerah storages were less than 50% full. Most of the remaining storages in the region's east were over 80% full, including the Hinze storage in the region's southeast. An inset line graph shows the time series of percentage-full storage volume between 1 July 2013–30 June 2021. South East Queensland storages at 30 June 2021 were 60% full, lower than last year.
Figure S2 Percentage-full volume on 30 June 2021 for each storage and total storage volume from 2013–2021 (inset)

 

  • In early December 2020, storage levels had dropped to the lowest level since March 2009.
  • Heavy rainfall in late-March 2021 resulted in a rise in storage levels across the region and levels peaked in early April 2021.
  • More detailed information on the individual storages within the region is available on the Bureau of Meteorology's Water Storage website.

 

Water liabilities

Farm irrigation, Queensland (istock © George Clerk)

 

  • Water liabilities in the South East Queensland region refer to the volume of allocation remaining on licence entitlements at the end of the 2020–21 year.

 

Table S1 Volume of surface water allocation remaining at 30 June 2021
Description Individual users (ML) Urban system (ML)
  Opening balance at 1 July 2020 0 0
add Allocation 90,573 483,113
less Allocated diversion 25,431 310,808
less Adjustment and forfeiture 65,142 172,305
  Closing balance at 30 June 2021 0 0

 

Table S2 Volume of groundwater allocation remaining at 30 June 2021
Description Individual users (ML)
  Opening balance at 1 July 2020 0
add Allocation 28,395
less Allocated diversion 7,510
less Adjustment and forfeiture 20,885
  Closing balance at 30 June 2021 0

 

  • All water supply licences for the region have a water management year that ends on 30 June.
  • As there are no carry-over provisions for water supply licences in the South East Queensland region, the portion of water allocation that has not been abstracted at the end of a water year is forfeited and the allocation remaining at the end of the year is 0 ML.
  • A more detailed description of water allocations in the South East Queensland region is given in the Water use section below.

 

Water flows

Brisbane River, SEQ region (istock © Wendy Townrow)

 

Figure S3 Water inflows and outflows for the region's water stores and systems during the 2020–21 year

 

  • Total surface water flows into the region's storages was around 3,723 GL. The key item contributing to surface water inflows was runoff, which made up 90% of the total surface water inflows.
  • For the sixth consecutive year, runoff was lower than average (based on modelled data from 1971–2021) due to relatively poor rainfall throughout most of the year.
  • A key item contributing to surface water outflows from the region's storages was river outflow, which made up 72% of the total surface water outflows. River outflow was below average due to the dry conditions and low runoff across the region.
  • Water taken from surface water and groundwater resources for consumptive use was 364 GL, around 11% of the total outflow (see Water use section below).

 

Water availability

Bar graph of annual surface water availability in the South East Queensland region for the years 2011–2021. Storage at 1 July plus estimated inflows during the year is plotted against the mean water availability (based on 1971–2021 data). Surface water available during 2020–21 was below average for the sixth consecutive year. Water availability was well above average during 2011–12 and 2012–13.
Figure S4 Annual surface water available in the South East Queensland region, 2011–12 to 2020–21

 

  • Physical surface water availability is calculated as the sum of storage at the start of the year (see Water assets) and estimated inflows into storages and rivers during the year (see Figure S3).
  • Surface water availability in the South East Queensland region in 2020–21 was below average for the sixth consecutive year.
  • Water taken during the year is influenced by the physical water availability. Typically, water taken from surface water resources is higher when water availability is low. This is discussed in more detail in the Water use section below.

 

Water use

Brisbane River, SEQ region (istock © zstockphotos)

 

Doughnut graphs of water supplied to different users in 2020–21. Surface water taken in the South East Queensland region was 345 GL, mostly for the urban system. Groundwater taken was 18 GL, mostly for individual users.
Figure S5 Water taken for consumptive use in the South East Queensland region in 2020–21

 

  • Total surface water diverted in the region was 345 GL.
  • 91% of the total surface water diverted was to the urban system by the Queensland bulk water supply authority, Seqwater.
  • 8% of the total diversion was for individual users (comprising allocated and non-allocated diversions) while 1% was for individual users under a statutory right.
  • Total groundwater extracted in the region was 18 GL.
  • 65% of groundwater extraction was for individual users (comprising both allocated and non-allocated extraction); 35% was used for the urban water system.

 

Bar graph of annual surface water allocation and diversion for different users in the South East Queensland region from 2011–12 to 2020–21. Most of the surface water allocations are associated with the urban system. Allocations for the urban system were similar to the previous few years. In 2020–21, 64% of the allocation for the urban system was taken, similar to the previous year. There has been a general increasing trend in surface water taken for the urban system since 2011–12. 28% of the allocation for individual users was taken. A small amount of non-allocated surface water is also taken for individual users and the urban system.
Figure S6 Surface water access allocations and diversions in the South East Queensland region for the years ending 30 June, from 2012–2021

 

  • In 2020–21, total surface water allocation was same as last year; 574 GL, mostly for urban system supply. 59% of the allocated surface water was taken.
  • Allocated diversions for urban supply were relatively low compared to the previous two years because of the relatively wet conditions compared to the previous two years.
  • Allocations for individual users were same as last year but diversions decreased by almost 50% from last year because of the favourable climate conditions.

 

Bar graph of annual groundwater allocation and extraction for different users in the South East Queensland region from 2011–12 to 2020–21. All the groundwater allocations are associated with individual users. The allocation in 2020–21 was same as the previous year. In 2020–21, 26% of the allocation for individual users was taken. Non-allocated groundwater is also taken for individual users and the urban system.
Figure S7 Groundwater access allocations and extractions in the South East Queensland region for the years ending 30 June, from 2012–2021

 

  • In 2020–21, total groundwater allocation was 18 GL, all for private and commercial use. 26% of the allocated groundwater was taken.
  • The groundwater allocation remains the same as the previous year.
  • Groundwater extractions for individual users were relatively low compared to the previous year. The lower groundwater supply compared to the last two years was influenced by the relatively better conditions across the region resulting in a reduced water demand from users.

 

Urban system supply

Stacked bar graph showing the annual water sourced for South East Queensland region's urban supply system during the period from 2010–11 to 2020–21. Each bar in the stack progressively represents surface water, groundwater, inter-region inflow, and desalinated water. Between 2010–11 and 2020–21 there was a general decreaseing trend in total water sourced for the urban system. Surface water is the predominant water source for the urban system. Key aspects of the graph are described in the text below the figure.
Figure S8 Water sources used in South East Queensland's urban water system during the 2020–21 year compared with the previous ten years

 

  • Total inflow to the water supply system was 340 GL, approximately 10% lower than last year.
  • Surface water inflow made up almost 92% of urban supply; groundwater and desalinated water made up 2% and 6% of the total respectively.
  • The contribution of desalinated water to urban supply was the highest since 2010–11. The continued dry conditions for three years meant Seqwater had to increase its reliance on desalinated water supply to meet urban demand.

 

Water market activity

Wyaralong Dam, SEQ region (Seqwater © 2010)

 

  • All trade or lease of water access entitlements or allocations is for surface water only.
  • In 2020–21, 5,524 ML of surface water entitlements were traded.
  • For more information on water markets in the region, see the Water Markets Dashboard.

 

Cultural and environmental water

Lamington National Park, SEQ region (istock © Robert Downer)

 

Cultural benefit

  • The Gold Coast, Moreton, Mary Basin and Logan Basin water plans define general and ecological outcomes, and outline strategies to achieve these outcomes. This includes water for social and cultural benefits.

 

Environmental benefit

Environmental water provisions

  • Environmental water provisions are defined for rivers in all four water plan areas (Gold Coast, Moreton, Mary Basin, and Logan Basin) to maintain the rivers' natural ecological processes.
  • Environmental water requirements are met using two different water management scenarios: planned, partly regulated surface water and planned, unregulated surface water.

 

Environmental water outcomes

  • The environmental outcomes under the four water plans have been derived in consideration of the current state of the water resources in the respective plan areas, recognising that the natural state of the water courses, lakes and springs has changed because of water infrastructure, flow supplementation and water use.
  • Environmental outcomes are generally assessed over a longer time frame and combine streamflow, water supply scheme and ecological research data.