National Water Account 2018

South East Queensland: Climate and water

  • Rainfall for 2017–18 was similar to average, following two years of below-average rainfall.
  • Most months of the year had below-average rainfall, with above-average rainfall in October and February.
  • Streamflows were mostly below average, except for record high October flows in the Maroochy River due to heavy rainfall in the north of the region.

Diagram showing summary of rainfall, soil moisture and streamflow conditions for South East Queensland region for 2017–18

For further information on the region's climate and water conditions during the 2017–18 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 falling 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 2017–18 year

 

  • Total area-averaged rainfall was 1,025 mm, which is similar to the mean annual rainfall of 1,042 mm.
  • Rainfall was higher than average in October and February; all other months had average to below-average rainfall.
  • October rainfall was well above average for most of the region, and highest on record in much of the northern part of the region. This was due to heavy falls from numerous rain-bearing systems.

 

 

Figure C2 Total monthly rainfall for the South East Queensland region during the 2017–18 year compared with the long-term average and percentiles for the region

 

  • Total rainfall in October was above the 90th percentile and approximately three times the October average.
  • Rainfall during August–September was well below average, due to a positive Southern Annular Mode and strong subtropical ridge which suppressed rain-bearing low pressure systems.

 

Actual evapotranspiration


Figure C3 Annual and monthly actual evapotranspiration deciles for the South East Queensland region during the 2017–18 year

 

  • Total area-averaged actual evapotranspiration was average to above-average for most of the region.
  • Actual evapotranspiration was below average in August–September across much of the region. This was due to low water availability, as a result of relatively poor rainfall during this 2-month period.
  • Above-average actual evapotranspiration during October–December 2017 may be attributed to increased water availability across the region following high rainfall in October.

Soil moisture

 


Figure C5 Annual and monthly soil moisture deciles for the South East Queensland region during the 2017–18 year

 

 

  • Annual soil moisture in the root zone (0–1 m depth) was average across most of the region.
  • Rainfall and soil moisture are typically closely aligned. For example, soil moisture in October–December 2017 and March 2018 was mostly above average due to high rainfall in October 2017 and the end of February 2018.
  • More information on soil moisture distribution across the region is available in the Australian Landscape Water Balance.

 

Streamflow responses

Streamflow

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 2017–18 year compared with the long-term average and percentiles

 

  • Monthly flows were generally below average for most of the year.
  • Record high flows for October were observed in the Maroochy River, due to several heavy rainfall events during the month in the northern part of the region.
  • Flows were above-average in the Maroochy River in February, and the Brisbane and Logan rivers in March, as a result of moderate to locally heavy falls in late February.
  • Total annual flows in the Brisbane, Bremer, Logan, and Albert rivers were below average. Annual flows for the Maroochy River were similar to the long-term average, due to high flows in October–December and February.

 

Major water reforms

  • Seqwater commenced dam safety upgrades to several storages (Leslie Harrison, Lake Kurwongbah, and Cooloolabin) during the 2017–18 year.
  • During 2017–18, Seqwater completed construction and commissioning of the Petrie Water Supply Zone Upgrade, connecting a further 100,000 residents in the Moreton Bay area to the South East Queensland Water Grid.