Murray–Darling Basin: Climate and water
Annual rainfall in the region was above average, largely due to rainfall over the southern part of the basin. Heavy rainfall in September 2016 over the entire region contributed to very high streamflows in the Murray and Darling river catchments during September–November 2016. Rainfall and streamflow throughout most of the remainder of the year were below average.
For further information on the region's climate and water conditions during the 2016–17 year scroll down this page or click on the links below:
Climate conditions
Rainfall
Figure C1 Annual and monthly rainfall deciles for the Murray–Darling Basin region during the 2016–17 year
- Total area-averaged rainfall for the year was 514 mm, which is above the mean annual rainfall of 462 mm.
- Higher rainfall primarily occurred over the southern part of the region during the year.
- In September 2016, large parts of the region experienced their highest rainfall on record for that month.
Figure C2 Total monthly rainfall for the Murray–Darling Basin region during the 2016–17 year compared with the long-term average and percentiles for the region
- In the first four months of the year (July–October 2016), the climate was influenced by a negative Indian Ocean Dipole phase that is associated with higher winter-spring rainfall. Rainfall across the region was above average during this 4-month period.
- Rainfall was below average for the remainder of the year with the exception of March, when persistent hevay rainfall and thunderstorms occurred during the entire month.
- Rainfall in June 2017 was well below the 10th percentile due to dominant high pressure systems that reduced the number of cold fronts and lows that typically occur across the region.
Actual evapotranspiration
Figure C3 Annual and monthly actual evapotranspiration deciles for the Murray–Darling Basin region during the 2016–17 year
- Total area-averaged actual evapotranspiration was 537 mm, higher than the mean value of 441 mm.
- The above-average evapotranspiration may be attributed to a combination of above-average temperatures across the region and increased water availability, particularly during July–October 2016 when above-average rainfall occurred.
Figure C4 Total monthly actual evapotranspiration for the Murray–Darling Basin region during the 2016–17 year compared with the long-term average and percentiles for the region
- Actual evapotranspiration was above average for most months of the year and above the 90th percentile during the first four months of the year (July–October 2016).
- Evapotranspiration was below average during a 2-month period (February–March 2017) when water availability was low due to relatively poor rainfall during the summer months.
Soil moisture
Figure C5 Annual and monthly soil moisture deciles for the Murray–Darling Basin region during the 2016–17 year
- Soil moisture in the root zone (0–1 m depth) was average to above average across the region.
- Rainfall and soil moisture are typically closely aligned. For example, above-average soil moisture during July–October 2016 reflects the above-average rainfall that occurred during that 4-month period.
- More information on soil moisture distribution across the Murray–Darling Basin region is available in the Australian Landscape Water Balance.
Streamflow responses
Streamflow
Figure C6 Key flow gauging stations along the main rivers within the Murray–Darling Basin region
- The Murray and Darling rivers are the two primary river systems within the region. Streamflow in the River Murray is influenced by dam operations and diversions for consumptive use.
- Ovens River represents a predominantly unregulated river in the region.
Figure C7 Total monthly flow for major rivers in the Murray–Darling Basin region during the 2016–17 year compared with long-term average and percentiles
- In the Murray and Darling rivers, most of the annual streamflow occurred during September–November 2016. The well above-average flow during this 3-month period was due to heavy rainfall during September 2016 across the entire region.
- Well above-average flows in the Ovens River during July–October 2016 reflect the above-average rainfall across the southern part of the region during this 4-month period.
- Flow in all three rivers for the remainder of the year (December 2016–June 2017) was generally below average, particularly in the Darling River.
- There was less flow response than expected following the above-average rainfall in March 2017, which can be attributed to the relatively low soil moisture conditions across the region following a dry summer.
Major water reforms
- Planning and construction commenced on a new 270 km pipeline from the River Murray near Wentworth to Broken Hill. The pipeline will secure long-term water supply for Broken Hill and surrounding communities.
- Construction of the pipeline is estimated to cost $500 million, which represents New South Wales' largest investment into regional water security on record.