Perth
17.12 Entitled diversion of allocated surface water to urban water system

Supporting information

This line item volume (81,553 ML) represents the total surface water diverted for urban water supply in the Perth region during the 2011–12 year.

Total volume of water diverted from each surface water resource to the urban water system during the 2011–12 year is given in the following table.

 

Volume of water diverted from each surface water resource to the urban water system during the 2011–12 year

Surface water resource

Water diverted (ML)

Storage

 

Canning

22,863

Churchman Brook

853

Mundaring

1,422

North Dandalup

3,586

Samson Brook

5,085

Serpentine and Serpentine Pipehead

18,072

South Dandalup

5,070

Stirling

6,789

Victoria

2,482

Wungong

15,164

Other

 

Murray River and tributaries (Dwellingup)

167

Total

81,553

 

Surface water made up approximately 25% of the inflows to the urban water supply system during the 2011–12 year. During the comparison year, surface water diverted to the urban water system was 115,629 ML, approximately 35% of the urban supply water (see Urban water system section of the 'Water resources and systems' note).

Quantification approach

Data source

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 2011–12 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 under in situ conditions, must be within 5% accuracy across the full flow rate range (Guidelines for water meter installation 2009).

Comparative year

This line item corresponds to line item '17.12 Surface water allocation diversion – urban water system' reported in the 2011 Account.