19.11 Transfer of water outside of region
The Barossa, Onkaparinga Summit Storage and Myponga water treatment plants (WTPs), located within the Adelaide region, supply potable water to customers outside the region. The following table summarises the volume (3,476 ML) of potable water exported during the 2010–11 year.
|Water treatment plant||Volume (ML)|
|Summit Storage (Onkaparinga)
Geographic information system (GIS) analysis was used to extract the service point numbers (SPNs) of meters that are outside the Adelaide region, but are supplied with water by WTPs within the Adelaide region. The SPNs were then used to extract water meter readings for the 2010–11 year for each meter from the CSIS database.
Water consumption was calculated by analysing the difference between consecutive meter readings and summed for 2010–11. To account for meter readings that occurred immediately before or after 2010–11, metered consumption was apportioned based on the following equation:
Vr = ( tr / tm ) × Vm
Vr = volume for metered period within 2010–11 (ML)
tm = length of period between meter readings (days)
tr = length of metered period within 2010–11 (days)
Vm = volume for metered period (ML).
Assumptions, Limitations, Caveats and Approximations
This line item is new to the 2011 Account. This line item corresponds in part to 20.7 Other lumped water distribution decreases reported in the 2010 Account.
In the 2011 Account the following changes were made that caused values of the 2009–10 year to be restated.
- potable water export to urban areas outside Adelaide region was reported here
- water treatment plant and wastewater treatment plant losses were reported at line item 19.20 Other urban water decreases.
Restatement of the value published in the 2010 Account was made as the change was material, and increased the accuracy and comparability of the information provided to the users of the National Water Account. The changes and their respective values are detailed in the following table below. The restated comparative year volume is 3,627 ML.
|2010 Account line item name
||Description||Volume at 30 June 2010 reported in 2010 Account (ML)
||Value difference to volume reported due to reclassification (ML)
||Volume at 30 June 2010 reported in 2011 Account (ML)|
|20.7 other lumped water distribution decreases||Potable water export||3,627||3,627|
|WTP plant losses||7,051||(7,051)|
|WWTP plant losses||726||(726)|