National Water Account 2020

Fitzroy: Climate and water

  • Total annual rainfall was below average for the third consecutive year.
  • The dry conditions resulted in very low streamflows for most of the year.


 

For further information on the region's climate and water conditions during the 2019–20 year scroll down this page or click on the links below:

 

About the region

  • The Fitzroy region has a sub-tropical, semi-arid climate with a high inter-annual variability in rainfall and streamflow.
  • Most of the rainfall occurs during the wet season (November–April). As a consequence, flow in the rivers is strongly seasonal and many of the region's rivers cease to flow during the dry season (May–October).

 

Climate conditions

Rainfall

Figure C1 Annual and monthly rainfall deciles for the Fitzroy region during the 2019–20 year

 

  • Total area-averaged rainfall for the year was 464 mm, well below the mean value of 676 mm.
  • The transition of the Southwest Indian Monsoon into the southern hemisphere was six weeks later than average and the latest on record. The delayed monsoon period meant very little rainfall occurred across the region at the start of the 2019–20 wet season, which contributed to the below-average annual rainfall.
  • This was the region's second consecutive year of well below-average wet season rainfall. Over the last two years, the region has experienced its second driest 24-month period in the last 100 years of record.
  • Thunderstorms and showers associated with a near-stationary coastal trough over southeastern Queensland in early February 2020 contributed to the above-average rainfall for that month.

 

Figure C2 Total monthly rainfall for the Fitzroy region during the 2019–20 year compared with the average and percentiles for the region

 

  • Rainfall was slightly above average in January 2020 and above average in February 2020. All other months had below-average rainfall.

 

Actual evapotranspiration

Figure C3 Annual and monthly actual evapotranspiration deciles for the Fitzroy region during the 2019–20 year

 

  • Total area-averaged actual evapotranspiration was below average across almost the entire region.
  • Evapotranspiration was below average during July 2019–January 2020 due to low water availability across the region following a dry year in 2018–19 (see the 2019 Account) combined with the delayed onset of the 2019–20 monsoon period.
  • Evapotranspiration was above average over large parts of the region during February–March 2020 due to increased water availability following the high rainfall in February 2020.

 

Soil moisture

Figure C5 Annual and monthly soil moisture deciles for the Fitzroy region during the 2019–20 year

 

  • Soil moisture in the root zone (0–1m depth) was average to below average across the region.
  • The delayed monsoon period meant very little rainfall occurred at the start of the 2019–20 wet season. By December 2019, root-zone soil moisture was well below-average and lowest on record over the entire southern part of the region.
  • Soil moisture was above average over large parts of the region during February–March 2020 following high rainfall in February 2020.
  • More information on soil moisture distribution across the Fitzroy region is available in the Australian Landscape Water Balance.

 

Streamflow responses

Streamflow


Figure C6 Key flow gauging stations along the main rivers within the Fitzroy region

 

  • The six main rivers in the region are the Fitzroy, Dawson, Nogoa, Mackenzie, Isaac, and Comet rivers, which correspond to the six sub-basins used for environmental water management (see the Water management section in 'Region description' for more information).

 

 

Figure C7 Total monthly flow for key rivers during the 2019–20 year compared with the average and percentiles

 

  • Streamflows were below average for most of 2019–20, reflecting the dry conditions experienced across the region. For example, total annual flow in the Fitzroy River at the Gap (Station 130005A) was 2,535 GL compared to the average value of 5,012 GL.
  • This was the third consecutive year of very low flows in the region's rivers throughout most of the year.
  • Streamflow was particularly low during the first part of the wet season (November–January) due to the delayed onset of the monsoon period. In December 2019, there was no flow in any of the region's major rivers and no flow occurred in the Fitzroy River for the entire first half of the wet season.
  • Almost all of the annual flow in the region occurred during February–March 2020 following the above-average rainfall in February 2020. Streamflow in the Dawson River, in the southern part of the region, was well above average during February 2020, reflecting the higher rainfall that occurred in February over the upper reaches of this catchment area.