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National Water Account 2018

Daly: Statement details

  • Heavy rainfall in late-January 2018 associated with a monsoon trough contributed to above-average annual runoff across the region.
  • Lower than average rainfall for most of the other months of the year, however, resulted in an annual drop in aquifer storage.

 



 

For further information on the regions water accounting statements scroll down this page or click on the links below:

 

Water assets

Groundwater assets

  • Volumes of water stored in the aquifers cannot be quantified due to a lack of available data; however, information on the total annual change in aquifer storage is available.

 

Figure S1  Graph of total annual change in aquifer volume in the region at 30 June 2018 compared with the previous 6 years
Figure S1 Total annual change in aquifer volume in the region at 30 June 2018 compared with the previous 6 years

 

  • Below-average rainfall for most months of the year contributed to an annual decrease in aquifer storage of 460,000 ML.
  • The aquifer recharge during the year was similar to the 4 years between 2013–16 when similar poor rainfall occurred during most of the wet season.
  • The increase in aquifer storage last year was due to high rainfall during the typically wetter months of the year; the very large increase in storage in 2011–12 was primarily attributed to well above-average rainfall over a 2-year period associated with the 2010–12 La Niña event.

 

Surface water assets

  • The volume of surface water in the region at 30 June 2018 was 12,973 ML, more than 98% of which is water in rivers. The remaining amount is water held in storages.
  • The volume of surface water at 30 June changes little from year to year.

 

Water liabilities

  • Water liabilities in the Daly region refer to the volume of allocation remaining on licence entitlements at the end of the 2017–18 year. 

 

Table S1 Volume of surface water allocation remaining at 30 June 2018
Description Individual users (ML) Urban system (ML)
 Opening balance at 1 July 201700
addAllocation5,8683,417
lessAllocated diversion9732,726
lessAdjustment and forfeiture4,895691
 Closing balance at 30 June 201800

 

Table S2 Volume of groundwater allocation remaining at 30 June 2018
Description Individual users (ML) Urban system (ML)
 Opening balance at 1 July 201700
addAllocation113,9252,359
lessAllocated diversion34,157279
lessAdjustment and forfeiture79,7682,080
 Closing balance at 30 June 201800

 

  • As there are no carry-over provisions for water supply licences in the Daly region, the portion of water allocation that has not been abstracted at the end of a water year is forfeited and the allocation remaining at the end of the year was 0 ML.
  • A more detailed description of water allocations and associated water rights in the Daly region is given in the Water access and use note.

 

Water asset increases

  • Total water asset increases for the year was 12,111,003 ML.
  • The key items contributing to water asset increases for the region were runoff and recharge: landscape, which made up around 90% of the surface water and groundwater increases, respectively.
  • Runoff was higher than average, mainly due to high rainfall associated with a monsoon trough in January 2018 (see Climate and water).
  • Recharge was relatively low, similar to the 4 years between 2013–16 when similar poor rainfall occurred during most months of the wet season.

 

Water asset decreases

  • Total water asset decreases for the year was 12,803,002 ML.
  • The key item contributing to water asset decreases for the region was outflow from surface water, which made up 89% of the total water asset decreases.
  • Outflow was almost 40% above average, largely due to the very high streamflow across the region during January–February 2018 (see Climate and water).
  • Groundwater decreases primarly represents discharge: surface water, which generally changes little from year to year.

 

Water flows

  • Total water inflows to the region was 12,111,003 ML, equal to the volume of Water asset increases.
  • Total water outflows from the region was 12,841,137 ML, slightly higher than the volume of Water asset decreases (12,803,002 ML) as it also includes flows corresponding to the accrual transactions—allocated diversions and allocated extractions (see the Water liabilities section above).
  • A detailed description of all the water flows associated with the surface water and groundwater stores is provided in the Water stores note.

 

Unaccounted-for difference

  • The unaccounted–for difference is the volume necessary to reconcile the opening water storage and closing water storage with the total water inflows and total water outflows reported in the water accounting statements.

 

Table S3 Calculation of unaccounted-for difference for the 2017–18 year
Description Volume (ML)
 Closing water storage balance at 30 June 2018
lessTotal inflows12,111,003
addTotal outflows12,841,137
addChange in water storage(461,635)
lessOpening water storage balance at 1 July 2017
 Unaccounted-for difference268,499

 

  • The unaccounted-for difference value is primarily attributed to uncertainties associated with the runoff estimate (see Methods).