13.4 Adjustment and forfeiture of inter–region commitment on surface water

Supporting information

The volume recognised in the water accounting statements (11,614 ML) represents the total forfeiture of surface water allocations for water supply to the Kalgoorlie Goldfields and Agricultural region, located outside of 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 for Mundaring Reservoir (which supplies water to the Kalgoorlie Goldfields and Agricultural region) 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 for Mundaring Reservoir less the total allocation diversion, as shown in the following table.


Total forfeiture of the inter-region commitment on surface water for the 2011–12 year



Volume (ML)


21.4 Surface water allocation announcement



17.14 Allocated surface water diversion



Forfeiture on 30 June 2012



Assumptions, limitations, caveats and approximations


Uncertainty information

The uncertainty estimate was not quantified.