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Canberra

                                                                                                   

30.4 Unaccounted for difference – water distribution system store

                             

Quantification approach   


The volume disclosed in the water accounting statements represents the difference between the measured opening and closing balances of water distribution system assets, after physical inflows and outflows have been applied.

The unaccounted-for difference is calculated according to the following table.

  Account Volume (ML)
  Opening balance water distribution system store (as at 01 July 2009)

524
add Total 19 Water distribution system inflows 51,267
minus Total 20 Water distribution system outflows 51,240
minus Closing balance water distribution system store (as at 30 June 2010) 612
  Unaccounted-for difference -61

The unaccounted-for difference represents less than 1% of the inflows and outflows for the water distribution system.

It is likely that the unaccounted-for difference is primarily attributed to errors associated in the following areas:

  • Line item 20.2 Leakages from water distribution system has been estimated. Estimations of leakage may have introduced error into the account.
  •  
  • Line item 20.3.2 Application of water from urban potable water supply system and recycled water supply system for irrigation or outdoor use has been calculated using the difference between the net inflows and outflows to the water distribution system. Actual volumes of outdoor garden usage were unable to be quantified.
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  • The impact of rainfall on the water distribution system store has not been quantified within the account.