13.2 Adjustment and forfeiture of surface water allocation – urban water system

Supporting information

This line item volume (158,604 ML) represents the total forfeiture of surface water allocations for the urban water system in the Perth region during the 2011–12 year.

Quantification approach

Data source

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

Provided by

Department of Water and Water Corporation.


The portion of surface water allocation that has not been abstracted at the end of the 2011–12 year is forfeited, i.e. there is no carry-over of entitlements into next year's account.

The forfeiture is calculated as the total annual allocation less total allocation diversion, as shown in the following table.


Total forfeiture of surface water allocation for the urban water system during the 2011–12 year



Volume (ML)


21.2 Surface water allocation announcement



17.12 Allocated surface water diversion



Forfeiture on 30 June 2012



Assumptions, limitations, caveats and approximations


Uncertainty information

The uncertainty estimate was not quantified.