Sydney

Urban water utilities diverted 6,295 ML from unregulated streams to the water distribution system during 2009–10 (see the following table).

This line item comprises three different data-sets. The method for each data-set is shown below.

Note a: Goulburn Mulwaree Council

Data source

Data spreadsheets.

Data provider

Goulburn Mulwaree Council.

Method

Diversions to the water treatment plants (WTPs) were measured at the plants. At Marulan WTP, outflow from the plant was measured using a flow meter.

Uncertainty

The volume is based on metered data. Estimated accuracy based on meter accuracy and professional judgment is +/–20%.

Approximations, assumptions, caveats/limitations

Nil.

Note b: Palerang Council

Data source

Database maintained as spreadsheets.

Data provider

Palerang Council.

Method

An ABB Magmaster-type induction meter was used to measure flow data.

Uncertainty

The volume is based on metered data. Estimated accuracy based on meter accuracy is +/–2%. Meters are calibrated annually by ABB (meter supplier).

Approximations, assumptions, caveats/limitations

Nil.

Note c: Sydney Water Corporation

Data source

Data managed and maintained in an internal data management system by the Sydney Water Corporation’s Operations Division (Hydraulic Systems Services).

Data provider

Sydney Water Corporation.

Method

Volumes were derived from metered outflow data from WTPs.

The flow meter data are continually monitored and recorded using the Integrated Instrumentation Control Automation and Telemetry System (IICATS). The data are stored within a complex data management system. Adjustments are made to the data (if necessary) to correct any interruptions, errors and so on. Data have been extracted for 2009–10 from the data management system.

Uncertainty

The volume is based on measured data. Estimated accuracy based on meter accuracy is +/–2%.

Approximations, assumptions, caveats/limitations

As data on inflow to each WTP is not available, metered outflow is assumed to be equal to the surface water taken. The volume taken from surface water can be higher than the outflow volume due to losses associated with pipe systems and the filtration process.

This line item applies to Sydney Water Corporation only for its water diversions from the Hawkesbury River to North Richmond WTP. All the other supplies to Sydney Water Corporation are made by the Sydney Catchment Authority.