14.2 Adjustment and forfeiture of groundwater allocation – urban water system

Supporting information

This line item volume (11,383 ML) represents the total forfeiture of groundwater allocations for the urban water system in the Perth region during the 2012–13 year.

Quantification approach

Data source

Department of Water, Water Resource Licensing database; Water Corporation, Operational Data Storage System database.

Provided by

Department of Water; Water Corporation.


The portion of groundwater allocation that has not been abstracted at the end of the year is forfeited; that is, there is no carry-over of entitlements into next year's account.

For all the groundwater licences within the Perth region that supply water to the urban water system, the licensed water management year is 1 July–30 June. The forfeiture that occurs at the end of the year is calculated as the total annual allocation for these groundwater resources less the total allocation diversion, as shown in the following table.

Total forfeiture of groundwater allocation for the urban water system during the 2012–13 year



Volume (ML)


22.2 Groundwater allocation announcements



18.12 Entitled extraction of allocated groundwater



Total forfeiture on 30 June 2013


Assumptions, limitations, caveats and approximations


Uncertainty information

The uncertainty estimate was not quantified.