National Water Account 2019

South East Queensland: Climate and water

  • Total annual rainfall was below average across the region for the fourth consecutive year.
  • Streamflows were very low reflecting the below-average rainfall and poor soil moisture conditions
  • Annual streamflow in the Brisbane River was the lowest in 12 years.

 

 

For further information on the region's climate and water conditions during the 2018–19 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 2018–19 year

 

  • Total area-averaged rainfall for the year was 746 mm, well below the mean value of 1,049 mm. Annual rainfall was the lowest on record in southern and inland parts of the region.
  • Rainfall was particularly low during January–February 2019, the typically wetter months of the year. In January, large parts of the region recorded their driest January on record.
  • The below-average rainfall throughout the spring 2018 and winter 2019 months was likely due to a positive phase of the Indian Ocean Dipole that influenced Australia's climate during those periods (see the Bureau's 2018–19 Climate Report for more information).
  • Above-average rainfall occurred across the entire region in October 2018 due to thunderstorm activity throughout the month.

 

Figure C2 Total monthly rainfall for the South East Queensland region during the 2018–19 year compared with the long-term average and percentiles for the region

 

  • Total rainfall in October was above the 90th percentile and more than double the October average.
  • Rainfall was only above average in October 2018 and March 2019. All other months had below-average rainfall.
  • Monthly rainfall was below the 10th percentile during January–February 2019, the typically wetter months of the year. Rainfall in January was the second lowest on record.

 

Actual evapotranspiration


Figure C3 Annual and monthly actual evapotranspiration deciles for the South East Queensland region during the 2018–19 year

 

  • Total area-averaged actual evapotranspiration was below average across most of the region, particularly the southern and inland areas, reflecting the dry conditions and low water availability across the region throughout the year.
  • Above-average evapotranspiration only occurred across the region during October–November 2018 due to increased water availability following the high rainfall in October 2018.

 

Soil moisture


Figure C5 Annual and monthly soil moisture deciles for the South East Queensland region during the 2018–19 year

 

  • Soil moisture in the root zone (0–1 m depth) was below average across most of the region; some areas in the south experienced their poorest soil moisture conditions on record.
  • Rainfall and soil moisture are typically closely aligned. For example, below-average soil moisture conditions across the entire region during the 3-month period from January–March is due to the very low rainfall that occurred during January–February 2019.
  • Soil moisture conditions during the year were only above average in October 2018 following the very high rainfall during that month.
  • More information on soil moisture distribution across the region is available in the Australian Landscape Water Balance.

 

Streamflow responses

Figure C6 Map of key flow gauging stations along the main rivers within the South East Queensland region
Figure C6 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 key rivers during the 2018–19 year compared with the long-term average and percentiles

 

  • Annual streamflows in all of the region's major rivers were below average, which reflects the low rainfall and poor soil moisture conditions experienced across the region.
  • Total annual flow in the Brisbane River at Gregors Creek (Station 143009A) was 9 GL compared to the average value of 252 GL. This was the river's lowest annual flow since the 2006–07 year.
  • Streamflows were very low for almost the entire year, particularly in the Brisbane, Bremer, and Logan rivers. In these three major rivers, the high rainfall in October 2018 had little impact on flows as the very dry soil moisture conditions during the winter–spring months in the upper reaches of these catchment areas meant much of the rainfall that occurred was soaked up by the soil.