Perth

This line item refers to the volume of water extracted from bore fields for urban water supply.

The volume of water extracted from each bore field for urban water supply during 2009-10 is given below.

Only a relatively minor volume of groundwater is allocated for the southwest region (including Mandurah), of which no groundwater was extracted during the 2009-10 reporting period. Most of the urban water supply for this region is supplied from Stirling and Samson reservoirs.

Data Source

Water Corporation: Operational Data Storage System.

Providing Agency

Water Corporation.

Method

Inflow of groundwater into the public water supply system is the total volume of groundwater extracted from the groundwater sources (bore fields) within the Perth region. Total water extracted is based on measured data collected at each source site using a cumulative water meter.

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

• It is assumed that the data provided by licensees are correct.
• There are several groundwater sources in the southwest region (i.e. Ravenswood and Park Ridge borefields) that have not been used for groundwater supply for several years and, therefore, are not included in the sub-account.