Sydney
1.1 Storages

The following tables provide a summary and breakdown of information on storages in the Sydney region. Storage volumes reported for the 30 June 2010 and 30 June 2011 year include dead storage volume.

 ¹Based on available data only

¹New rating tables were introduced on the 1 July 2010. This information has been captured in the 2011 closing volume data. To remain consistent with 2010 Account, opening volumes for the 2011 Account have remained the same as the 2010 closing volume.

² The volume available to Sydney Catchment Authority from Tallowa Dam under their water management licence was reduced from 35,000 ML to 7,500 ML on 1 July 2010. This has affected the amount of dead storage volume recorded in the dam between the comparative year.

³ Blue Mountains storage reservoirs include Medlow Reservoir, Greaves Creek Reservoir, Upper Cascade Reservoir, Middle Cascade Reservoir and Lower Cascade Reservoir.

¹ Based on available data only.

Shoalhaven City Council pumps its entitled water from the Shoalhaven River (diverted from Lake Yarrunga) at the Burrier pumping station. Bamarang and Flat Rock Creek storages receive water pumped from Burrier pumping station. In addition to this water, these two storages have their own natural run-off. During the 2010–11 year, all water received from the Burrier pumping station was diverted to water treatment plants or commercial customers (in accordance with established service agreements). Therefore, volumes shown in the above table do not include water pumped from Burrier.

Water from Danjera Reservoir is diverted to water treatment plants when there is insufficient diversion from Lake Yarrunga (Tallowa Dam) for pumping at Burrier. Such a diversion was not made during the 2010–11 year.

• Lake Lyell: ultra sonic level readings converted to a volume using a rating table in a spreadsheet.

• Lake Wallace: telemetered level data from ultrasonic level sensors and radio telemetry system converted to a volume using a rating table in a spreadsheet.

• Thomsons Creek Reservoir: telemetered level data from pressure sensors and radio telemetry system converted to a volume using a rating table in a spreadsheet.

The volume is based on measured data. Uncertainty value based on meter accuracy is +/– 5%.

Telemetered level data converted to a volume using a rating table in a spreadsheet. For Pejar Reservoir, manual level readings were used for some of the 2010–11 period, because level sensors were non-functional due to low water levels.

The volume is based on measured data. Uncertainty value based on meter accuracy and professional judgment is +/– 5%.

Manual level readings converted to a volume using a rating table in a spreadsheet.

Information on dead storage volume is not available.

The volume is based on measured data. The uncertainty estimate was not quantified.

Telemetered level data were converted to a volume using a rating table.

Nil.

Water level by visual inspection of gauging boards and from hydrometric sensors. Level readings converted to volume using rating tables. Storage tables for reservoirs are developed from bathymetric surveys and other methods.

The volume is based on measured data. Estimated uncertainty based on accuracy of sensors and other level measuring devices, and professional judgment on rating tables is +/– 5%.

Water levels received from level sensors located in the storages through council's radio telemetry system are converted to a volume using rating tables. In addition, water levels obtained by operation officers are loaded into a spreadsheet where rating tables produce storage volume.

Information on dead storage volume is not available.

The volume is based on measured data. Estimated uncertainty based on sensor accuracy, organisational practice and professional judgment on rating tables is +/– 10%.

The following table compares the value at 30 June 2010 reported in this account with the corresponding value reported in the 2010 Account.