National Water Account 2017

Murray–Darling Basin: Water stores

Above-average rainfall during the year, particularly during July–October 2016, contributed to high runoff across the region and an increase in storage volumes. The increase in the region's water availability led to an increase in water use compared to the previous year.

 

 

 

For a water balance on each of the region's water stores for the 2016–17 year scroll down this page or click on the links below:

 

Surface water store

Cawndilla and Menindee lakes. Source: Bureau of Meteorology © Paul Sheahan

 

Table S5 Water balance for the surface water store
  2017
ML
2016
ML
Opening surface water store 12,913,129 12,458,729
Inflows 43,230,639 23,724,261
Outflows (37,327,023) (23,269,861)
Balancing item (0) (0)
Closing surface water store 18,816,745 12,913,129

 

  • The volume of surface water in the region increased from 12,913,129 ML at 1 July 2016 to 18,816,745 ML at 30 June 2017.
  • The balancing item of 0 ML does not imply that there are no uncertainties associated with the surface water store. Errors and uncertainties are incorporated within the river and floodplain losses, which is estimated using a water balance approach (see Methods).

 

Surface water flows

 

Figure S5 Water inflows and outflows for the surface water store during the 2016–17 year

 

  • The largest natural water flow was runoff, which was 83% higher than the previous year reflecting the improved rainfall conditions experienced across the region (see Climate and water).
  • Evaporation was also higher than that which occurred during the previous year due to a combination of above-average temperatures and increased water availability across the region, particularly during the first few months of the year (July–October 2016).
  • The largest water transfer in the region (delivery: inter-region agreement) comprised transfers from Snowy Hydro Limited (2,655,543 ML) and Glenelg River (3,559 ML). The delivery of water from Snowy Hydro Limited increased by 11% from the previous year due to the increased releases from the Snowy system to the River Murray.

 

Figure S6 Allocated surface water diversions during the 2016–17 year in the region's key water management areas 

Figure S6 Allocated surface water diversions during the 2016–17 year in the region's key water management areas

 

  • Total surface water diverted in the region was 10,577,521 ML; this comprised of 8,105,644 ML (77%) allocated diversions and 2,471,877 ML (23%) non-allocated diversions.
  • More than 20% of the total diversion was for environmental purposes, with the largest supplies in NSW Murray and Lower Darling, and SA River Murray water resource plan areas; less than 4% was used for the urban system.
  • Total net surface water diversion in the region was 10,032,932 ML.
  • For a more detailed description of the water usage in the region, and the associated entitlements, see the Surface water rights note.

 

Groundwater store

Bore channel near Walgett. Source: Murray–Darling Basin Authority © Arthur Mostead

 

Table S6 Water balance for the groundwater store
  2017
ML
2016
ML
Opening groundwater store 3,333,740 3,333,740
Inflows 2,293,665 671,709
Outflows (2,617,752) (1,685,068)
Balancing item 324,087 1,013,359
Closing groundwater store 3,333,740 3,333,740

 

  • The volume of groundwater in the region is equivalent to the sustainable diversion limit and, therefore, remains unchanged from year to year.
  • It is likely that the balancing item is primarily attributed to uncertainties associated with groundwater recharge from the landscape and groundwater discharge to the landscape, which are estimated from a groundwater model (see Methods).

 

Groundwater flows

 

Figure S7 Water inflows and outflows for the groundwater store during the 2016–17 year

 

  • The largest natural groundwater flows were recharge: landscape and recharge: surface water, which combined make up almost all of the total inflows into the region's aquifers.
  • Groundwater recharge was higher than the previous year, which reflects the improved rainfall and streamflow conditions across the region, particularly during the winter and spring months (see Climate and water).

 

Figure S8 Allocated groundwater extractions during the 2016–17 year in the region's key water management areas 

Figure S8 Allocated groundwater extractions during the 2016–17 year in the region's key water management areas

 

  • Total groundwater extracted in the region was 1,199,842 ML, similar to the previous year.
  • 77% of the total extraction was for individual users; 3% was used for the urban system, and 20% was for individual users under a statutory right.
  • No groundwater extractions were made for environmental purposes during the year.
  • For a more detailed description of the water usage in the region, and the associated entitlements, see the Groundwater rights note.