Perth
11.12 Allocation diversion of surface water to urban water system

Supporting Information
Quantification Approach
Comparative year

Supporting Information

This line item refers to the volume of water abstracted from major surface water storages for urban water supply.

Total surface water abstracted from each surface water resource for urban water supply to the Perth region during the 2010–11 year is given in the following table.

Volume of water diverted from each storage to the urban water system during the 2010–11 year
Surface water resource	Storage	Total water abstracted (ML)
Perth city area
Canning River	Canning and Araluen Pumpback	15,113
Churchman Brook	Churchman Brook	480
Conjurunup Creek	Conjurunup Pumpback	388
Helena River	Mundaring	1,631
Kangaroo Gully	Kangaroo Gully Diversion	15
Munday Brook	Victoria and Bickley Pumpback	2,178
North Dandalup River	North Dandalup	9,641
Serpentine River	Serpentine and Serpentine Pipehead	29,019
South Dandalup River	South Dandalup and Lower South Dandalup Pumpback	18,589
Wungong Brook	Wungong	17,621
Southwest area
Harvey River	Stirling	19,250
Harvey River	Wokalup Pipehead	0
Samson Brook	Samson and Samson Pipehead	1,644
Other
Murray River and tributaries (Dwellingup)		60
Murray River and tributaries (Williams)		0
Total allocation diversion		115,629

Quantification Approach

Data Source

Water Corporation: Operational Data Storage System.

Provided by

Water Corporation.

Method

Total water abstracted from surface water storages for urban water supply within the Perth region is equal to the total annual water released from the storages during the 2010–11 year. The water volumes released from the storages are metered at the outlet continuously and reported on a monthly basis.

Assumptions, Limitations, Caveats and Approximations

Nil.

Uncertainty Information

Expected error for water meters is +/– 5%.

The Department of Water requires that all water meters, when tested in situ conditions, must be within 5% accuracy across the full flow rate range (Guidelines for water meter installation 2009).

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 11.12
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
11.12 Allocation diversion of surface water to urban water system	19.8.5 Allocation diversion of regulated flows–urban holder	141,276	141,276	Change in line item name and number

Perth11.12 Allocation diversion of surface water to urban water system