Perth
5.1 Surface water allocation remaining

Supporting information
Quantification approach

Supporting information

The volume recognised in the water accounting statements (17,709 ML) represents the volume of surface water allocation remaining for individual licence entitlements at the end of the 2012–13 year.

This line item refers to all surface water supply in the Perth region not related to urban water systems or irrigation schemes. It includes water supply to individual users in the mining, industrial and agricultural sectors.

Quantification approach

Data source

Water Resource Licensing database.

Provided by

Department of Water.

Method

The allocation remaining at 30 June 2013 was calculated as shown in the following table.

Volume of surface water allocation remaining at the start and end of the 2012–13 year
	Account	Volume (ML)
	Opening balance (at 1 July 2012)	14,912
add	21.1 Surface water allocation announcements	33,886
less	17.11 Entitled diversion of allocated surface water to users	30,817
less	13.1 Adjustment and forfeiture of surface water allocation	272
	Closing balance (at 30 June 2013)	17,709

Generally, the water management year for private users commences on the date the licence is issued. Consequently, there are a high number of private water users whose licence anniversary falls outside the standard water year (1 July–30 June). As a result, the allocation remaining at 30 June 2013 is relatively high (more than 50% of the allocation announcement).

Assumptions, limitations, caveats and approximations

Nil.

Uncertainty information

The uncertainty estimate was not quantified.

Perth5.1 Surface water allocation remaining