6.2 Groundwater allocation remaining – urban water system

Supporting information

This line item volume (0 ML) represents the volume of groundwater allocation remaining for urban water supply licence entitlements in the Perth region at the end of the 2011–12 year.

Quantification approach

Data source

Water Resource Licensing database and licensee meter readings.

Provided by

Department of Water.


The licensed water management year for all bore fields within the Perth region is 1 July–30 June. For these licences, any unused allocation at the end of the water management year is forfeited and therefore the allocation remaining at the end of the reporting period is zero.

Prior to the 2011–12 year, the groundwater supply licences for the Gingin bore field had a water management year that ended on 30 September (i.e. they did not end on 30 June). Consequently, the allocation remaining at the end of the 2010–11 year was 154 ML. These particular licences were terminated during the 2011–12 year (see line item 14.2). 

The allocation remaining at 30 June 2012 was calculated as shown in the following table.

Volume of groundwater allocation remaining for the urban water system at the start and end of the 2011–12 year


Volume (ML)


Opening balance (at 30 June 2011)



22.2 Groundwater allocation announcement



18.12 Groundwater allocation extraction



14.2 Adjustment and forfeiture of groundwater allocation



Closing balance (at 30 June 2012)



Assumptions, limitations, caveats and approximations


Uncertainty information

The uncertainty estimate was not quantified.