Perth
13.4 Adjustment and forfeiture of inter-region commitment on surface water

Supporting Information

This line item refers to the total forfeiture of water allocations for Helena River (Mundaring Reservoir), which supplies water to the Kalgoorlie Goldfields, located outside of the Perth region.

Quantification Approach

Data Source

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

Provided by

Department of Water.

Method

The portion of surface water allocation for Helena River (which supplies water to the Kalgoorlie Goldfields and Agricultural region) that has not been abstracted at the end of the 2010–11 year is forfeited. That is, there is no carryover of entitlements into next year's account.

The forfeiture is calculated as the total annual allocation for Helena River minus the total allocation diversion, as shown in the following table.

 

Total forfeiture of the inter-region commitment on surface water for the 2010–11 year

 

 

Volume (ML)

 

21.4 Allocation announcement

36,300

less

17.14 Allocation diversion

25,851

 

Forfeiture on 30 June 2011

10,449

 

Assumptions, Limitations, Caveats and Approximations

Nil.

Uncertainty Information

The uncertainty estimate was not quantified.

Comparative year

The following table presents substantive changes in the line item reported in this 2011 Account with the corresponding line item in the 2010 Account.

 

Comparative year information for line item 13.4

2011 Account line item

2010 Account line item

2011 Account volume for the 2009–10 year (ML)

2010 Account volume for the 2009–10 year (ML)

Change from the 2010 Account to the 2011 Account

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

26.5 Other lumped surface water liability decreases

9,642

9,642

Change in line item name and number