Border Rivers: Climate and water

  • Total annual rainfall was well below average for the third consecutive year.
  • Heavy rainfall in February 2020 resulted in higher streamflows during that month.
  • Streamflows over the rest of the year were well below average.

Schematic representation of the Border Rivers catchment. In 2019–20, rainfall was 434 mm, less than average for the third consecutive year. Streamflow in the Macintyre River in 2019–20 was 160 GL compared to the average value of 995 GL. Soil moisture was below average.

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

 

About the catchment

  • The Border Rivers catchment lies within the northeastern part of the Murray-Darling Basin.
  • Average annual rainfall ranges from approximately 400 mm in the west to 800 mm in the east.
  • The catchment's climate is sub-tropical. Rainfall occurs throughout the year with most rainfall occurring during the summer months. Higher streamflows typically occur during these months.

 

Climate conditions

Figure C1 Annual and monthly rainfall deciles for the Border Rivers catchment during the 2019–20 year

 

  • Total area-averaged rainfall for the year was 434 mm, less than the mean value of 625 mm and the lowest on record in some parts of the catchment.
  • This was the catchment's third consecutive year of very low rainfall. Over the last three years, the region has experienced its driest 36-month period on record.
  • Rainfall was very low during the latter half of 2019. The below-average rainfall throughout July–December 2019 was influenced by a positive phase of the Indian Ocean Dipole, one of the strongest on record, as well as a negative phase of the Southern Annular Mode at the end of 2019 (see the Bureau's 2019–20 Climate Report for more information).
  • There was some rainfall relief during the early part of 2020 as tropical moisture associated with warmer than average sea surface temperatures off the northwest coast of Australia moved across the continent and combined with southern cold fronts to produce high rainfall across the catchment.
  • Thunderstorms and showers associated with a near-stationary coastal trough over southeastern Queensland in early February 2020 contributed to the well above-average rainfall for that month.

 

Soil moisture

Figure C2 Annual and monthly soil moisture deciles for the Border Rivers catchment during the 2019–20 year

 

  • Soil moisture in the root zone (0–1 m depth) was below average across most of the catchment.
  • In July 2019, root-zone soil moisture was already well below average over most of the catchment following a very dry 2018–19 year. Continued dry conditions during the latter half of 2019 meant that by December 2019, root-zone soil moisture was still well below average and lowest on record over some parts of the catchment.
  • Soil moisture was above average over most of the catchment during February–March 2020 following the high rainfall in February 2020.
  • More information on soil moisture distribution across the catchment is available in the Australian Landscape Water Balance.

 

Streamflow responses

Map of key gauging stations. Macintyre River at Goondiwindi, station number 416201A, is in the central part of the region. Dumaresq River at Farnbro, station number 416310A, is in the eastern part of the catchment. Macintyre River at Inverell (Middle Creek), station number 416016, is in the region's southeast.
Figure C3 Key flow gauging stations along the main rivers within the Border Rivers catchment

 

  • The Macintyre and Dumaresq rivers are two primary tributaries of the Barwon River. The upper reaches of these tributaries are relatively undisturbed.
  • Streamflow in the lower Macintyre and Barwon rivers is influenced by dam operations and diversions for consumptive use.

 

Figure C4 Total monthly flow for major rivers in the Border Rivers catchment during the 2019–20 year compared with the average and percentiles

 

  • Streamflows were well below average for most of the year reflecting the dry conditions experienced across the region. For example, total annual flow in the Macintyre River at Goondiwindi (Station 416201A) was 160 GL compared to the average value of 995 GL.
  • This was the third consecutive year of low streamflow in the region's rivers throughout most of the year.
  • Streamflow was particularly low during the latter half of 2019. In December 2019, there was no flow in any of the region's major rivers and no flow occurred in the Dumaresq and upper Macintyre rivers for the entire 2019 year.
  • Most of the annual flow in the region occurred during February 2020 following the above-average rainfall in that month. Streamflow was close to average in the Macintyre River and above average in the Dumaresq River during February 2020.