13.1 Adjustment and forfeiture of surface water allocation

Supporting information

The volume recognised in the water accounting statements (272 ML) represents the total volume of terminated surface water licences for individual users in the Perth region during the 2012–13 year. This line item refers to all surface water supply not related to urban water systems or irrigation schemes.

Quantification approach

Data source

Water Resource Licensing database.

Provided by

Department of Water.


The portion of surface water allocation that has not been abstracted at the end of the year is forfeited. The forfeiture is calculated as the total annual allocation for each licence minus total allocation diversion; however, given that the volume of abstraction is estimated to be the full allocation (refer to line item 17.11 Entitled diversion of allocated surface water to users), this component of the forfeiture is assumed to be zero.

Entitlements that are terminated during the year are also considered to be forfeitures.

Assumptions, limitations, caveats and approximations

Given that the abstraction data are estimated, the forfeiture is subject to the same assumptions and limitations of the abstraction data (refer to line item 17.11 Entitled diversion of allocated surface water to users).

Uncertainty information

The uncertainty estimate was not quantified.