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South East Queensland

                                                                                                   

30.2 Unaccounted-for difference — connected surface water store

                             

Supporting information   


The unaccounted-for difference in the connected surface water store was calculated as 416,387 ML.

The unaccounted-for difference is some 20% of the closing balance and 13% of the inflows to the store.

Line item 13.4.1 Rainfall-runoff to connected surface water accounted for 89% of all connected surface water store increases,  while line item 14.2 Surface water flow out of region accounted for 70% of connected surface water store decreases. A small inaccuracy in either of these terms could have resulted in the majority of the unaccounted-for difference.

The positive unaccounted-for difference could be due to overestimation of inflows, such as line item 13.4.1 Rainfall-runoff to connected surface water, or underestimation of outflows, such as line item 14.2 Surface water flow out of region.

The table below shows the unaccounted-for difference for the connected surface water store, groundwater store and water distribution system store, together with total water storage.


Unaccounted-for difference for year ending 30 June 2010
  Connected surface water store (ML) Groundwater store 1,2 (ML) Water distribution system store (ML) Total water storage (ML)
Measured opening balance 1,743,538 9,340 465 1,753,343
Total inflows 3,045,426 0 242,605 3,288,031
Total outflows 2,281,666 5,556 238,699 2,525,921
Calculated closing balance 2,507,298 3,784 4,371 2,515,453
Unaccounted-for difference 416,387 (5,556) 3,906 414,737
Net water assets 2,090,911 9,340 465 2,100,716

Table notes:

  1. Groundwater inflows were not included in the water accounting  statements as they could not be quantified accurately due to a lack of  available data. Only a small proportion of the groundwater outflows were  included in the water accounting statements, as most could not be quantified  accurately due to a lack of available data. Outflows are for the entire SEQ  region, not just the Benefitted Area of the Central Lockyer water supply scheme  (WSS)
  2. Groundwater store includes only the Benefitted Area of the  Central Lockyer WSS.