Perth
12.9 Allocation diversion of surface water to irrigation scheme

Supporting Information

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

Quantification Approach

Data Source

Harvey Water: Supervisory Control and Data Acquisition system.

Provided by

Department of Water.

Method

Water inflow into the irrigation water supply system during the 2010–11 year is equal to the total annual water released from the storages. The water volumes released from the storages are metered at the outlet continuously and reported on a monthly basis.

On occasions where there is equipment failure at the storages resulting in missing data, both Harvey Water and Water Corporation are involved in infilling these gaps in record to estimate the volume of water supplied to the irrigation scheme.

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 12.9

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

12.9 Allocation diversion of surface water to irrigation scheme

19.8.8 Allocation diversion into the urban water supply system–other lumped

45,560

45,560

Change in line item name and number