9.7 Delivery of water from outside region

Supporting information

The volume reported in the water accounting statements (1,824 ML) represents the water transferred from the Collie River Irrigation District, which lies outside the Perth region boundary, into the Harvey Reservoir during the 2012–13 year.

Quantification approach

Data source

Supervisory Control and Data Acquisition system.

Provided by

Harvey Water.


The total volume of water transferred into Harvey Reservoir from the Collie River Irrigation District is based on measured data observed at the pump station located at the border of the Collie River and Harvey irrigation districts.

Assumptions, limitations, caveats and approximations

It is assumed that the volume of water measured at the flow meter at the border of the Collie River and Harvey irrigation districts is equal to the inflow at Harvey Reservoir (i.e. no leaks or transmission losses). This is a reasonable assumption given the transfer occurs via a closed pipe.

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 (Department of Water 2009c).