South East Queensland: Climate and water

  • Total annual rainfall was below average for the sixth consecutive year.
  • Heavy rainfall in March 2021 resulted in very high streamflows during that month.
  • Streamflows over the rest of the year were generally well below average.

Schematic representation of the South East Queensland region. In 2020–21, rainfall was 1,024 mm, less than average for the sixth consecutive year. Streamflow in Brisbane River in 2020–21 was 11 GL compared to the average value of 237 GL. Soil moisture was average.

For further information on the region's climate and water conditions during the 2020–21 year scroll down this page or click on the links below:

 

About the region

  • The South East Queensland region has a subtropical climate. Rainfall occurs throughout the year with most rainfall occurring during the summer and autumn months. Higher streamflows typically occur during these months.

 

Climate conditions

Rainfall

Figure C1 Annual and monthly rainfall deciles for the South East Queensland region during the 2020–21 year

 

  • Total area-averaged rainfall for the year was 1,024 mm, below the mean value of 1,056 mm.
  • The annual rainfall in 2020–21 was much higher than the previous two years when the region experienced its driest 24-month period since 1918–20.
  • A weak La Niña influenced Australia's climate during the spring–summers months, which typically brings above-average rainfall; however, rainfall was below average across the South East Queensland region throughout most of this period.
  • Heavy rainfall associated with a slow-moving low pressure system that impacted the region in late-March 2021 contributed to the well above-average rainfall for that month, particularly over the southern part of the region (see the Bureau's 2020–21 Climate Report for more information).

 

Figure C2 Total monthly rainfall for the South East Queensland region during the 2020–21 year compared with the average and percentiles for the region

 

  • Rainfall was above the 90th percentile in March 2021 and almost double the monthly average.
  • Rainfall in November 2020 was well below the 10th percentile for that month.

 

Actual evapotranspiration

Figure C3 Annual and monthly actual evapotranspiration deciles for the South East Queensland region during the 2020–21 year

 

  • Total area-averaged actual evapotranspiration was average to below average across the region.
  • Evapotranspiration was low throughout most of the year reflecting the dry conditions and low water availability, particularly during the 2020 winter–spring months.
  • Evapotranspiration was above average over large parts of the region during April–June 2021 due to increased water availability following the high rainfall in late-March 2021.

 

Soil moisture

Figure C4 Annual and monthly soil moisture deciles for the South East Queensland region during the 2020–21 year

 

  • Soil moisture in the root zone (0–1 m depth) was average across most of the region.
  • During the latter half of 2020, root-zone soil moisture was average to below average across the region reflecting the low rainfall during the winter–spring months.
  • Soil moisture was well above average over large parts of the region during April–May 2021 following the high rainfall in late-March 2021.
  • More information on soil moisture distribution across the region is available in the Australian Landscape Water Balance.

 

Streamflow responses

Map of key gauging stations. North Maroochy River at Eumundi, station number 141009A, is located in the north of the region. Brisbane River at Gregors Creek, station number 143009A, is in the northwest of the region. Bremer River at Walloon, station number 143107A, is near the town of Ipswich. Logan River at Yarrahappini, station number, 145014A, and Albert River at Bromfleet, station number 145102B, are in the southern part of the region.
Figure C5 Key flow gauging stations along the main rivers within the South East Queensland region

 

  • The five main rivers in the region are the Albert, Brisbane, Logan, Bremer and Maroochy rivers.
  • The seasonal flow characteristics of these rivers reflect the rainfall pattern of the region, where most rainfall occurs between November and March.

 

Figure C6 Total monthly flow for major rivers in the South East Queensland region during the 2020–21 year compared with the average and percentiles

 

  • Streamflows were below average for most of 2020–21 reflecting the dry conditions experienced across the region, particularly during the latter half of 2020.
  • Total annual flow in the Brisbane River at Gregors Creek (Station 143009A) was 11 GL compared to the average value of 237 GL. This was the third consecutive year of very low flows in the river.
  • Most of the annual flow in the region occurred during March 2021 following the above-average rainfall in that month. Streamflow in the Bremer, Logan, and Albert rivers, in the southern part of the region, was above the 90th percentile during March 2021, reflecting the higher rainfall that occurred over the upper reaches of these catchment areas.
  • Streamflow was also high in the Logan, Albert, and North Maroochy rivers during December 2020 reflecting the higher December rainfall over these river catchment areas in the southeast and northeast parts of the region (see Rainfall).