Perth
5.2 Surface water allocation remaining – urban water system

Supporting information

This line item volume (119 ML) represents the volume of surface water allocation remaining for urban water supply licence entitlements in the Perth region at the end of the 2011–12 year.

Quantification approach

Data source

Water Resource Licensing database and licensee meter readings.

Provided by

Department of Water.

Method

For all but one of the 12 surface water urban supply licences, the licensed water management year is 1 July–30 June. For these licences, any unused allocation at the end of the water management year is forfeited and therefore the allocation remaining at the end of the reporting period is zero.

The water supply licence for Dwellingup has a water management year that ends on 30 September. Therefore, the allocation remaining at the end of the 2011–12 year for the Perth region is the unused component of the annual allocation for the Dwellingup water resource.

The allocation remaining at 30 June 2012 was calculated as shown in the following table.


Volume of surface water allocation remaining for the urban water system at the start and end of the 2011–12 year

 

Dwellingup account

Volume (ML)

 

Opening balance (at 30 June 2011)

119

add

Allocation announcement (on 1 Oct 2011) (see line item 21.2)

167

less

Abstraction up to 30 June 2012 (see line item 17.12)

167

less

Forfeiture (on 30 Sept 2011)

0

 

Closing balance (at 30 June 2012)

119

 

Assumptions, limitations, caveats and approximations

Nil.

Uncertainty information

The uncertainty estimate was not quantified.