Perth
9.7 Delivery of water from outside region

This line item refers to bulk deliveries of water from outside the Perth region boundary into surface water storages within the Perth region.

The volume of water transferred into storages during the 2010–11 year for each bulk water delivery is given in the following table.

 

Volume of water transferred into storages from outside the region during the 2010–11 year

Water delivery	Data provider	Volume (ML)
Stirling Reservoir from Harris Reservoir	Water Corporation	48
Harvey Reservoir from Collie Irrigation District	Harvey Water	3,167
Total		3,215

 

In terms of the bulk delivery of water from the Harris Reservoir, this volume of water was not deliberately transferred to Stirling Reservoir. A total of 48 ML was accidently discharged into Stirling Reservoir via a partially open valve during a period of water transfer from Harris Reservoir to Worsley Refinery, a private user outside the region.

Water Corporation: Operational Data Storage System database, Harvey Water: Supervisory Control and Data Acquisition system.

Water Corporation Harvey Water

There were two bulk deliveries of water from outside the Perth region boundary into major surface water storages within the Perth region during the 2010–11 year.

The total volume of water transferred into Stirling Reservoir from Harris Reservoir is based on measured data observed at the flow meter at Harris Dam. The total volume of water transferred into Harvey Reservoir from the Collie Irrigation District is based on measured data observed at the pump station located at the border of the Collie River and Harvey Water Irrigation Districts.

It is assumed that the volume of water measured at the flow meter at Harris Dam is equal to the inflow at Stirling Reservoir (i.e. no leaks or transmission losses). This is a reasonable assumption given the transfer occurs via a closed pipe.

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).

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 9.7

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
9.7 Delivery of water from outside region	13.6.5 Other lumped delivery of water transferred-in to connected surface water	1,902	1,902	Change in line item name and number