Perth

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

Total surface water abstracted for each irrigation district during 2009-10 is given below.

Data source

Harvey Water: SCADA system.

Western Australian Department of Water: Water Resource Licensing database.

Data provider

Harvey Water and the Western Australian Department of Water.

Method

Water inflow into the irrigation supply system during the reporting period is equal to the total annual water released from the reservoirs. The water volumes released from the reservoirs are metered at the outlet continuously and reported on a monthly basis.

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

Uncertainty

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 (Department of Water 2009)

Approximations, assumptions, caveats/limitations

Nil.