Sydney
1.1 Storages

Supporting Information

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.

Volumes for storages – summary

Storage

Total storage capacity (ML)

Dead storage volume (ML)

Volume (ML)

30 June 2010

Volume (ML)

30 June 2011

All

2,863,622

190,9511

1,708,184

2,239,105

 1Based on available data only

Breakdown of storage volumes at the beginning and end of the 2010–11 year for storages managed by the Sydney Catchment Authority

Storage reservoir

Total capacity (ML)

Dead storage volume (ML)

Volume (ML)

30 June 2010

Volume (ML)

30 June 2011

Cataract1

97,370

180

64,730

77,710

Cordeaux

93,640

0

51,230

74,120

Avon1

214,360

67,660

153,440

167,480

Nepean1

69,100

370

58,280

53,350

Woronora

71,790

0

25,960

32,820

Lake Burragorang1 (Warragamba Dam)

2,031,000

4,000

1,126,830

1,571,640

Prospect1

48,200

14,870

45,310

45,590

Wingecarribee1

25,880

1,780

20,120

20,560

Fitzroy Falls1

22,920

12,920

22,320

21,710

Lake Yarrunga2 (Tallowa Dam)

90,000

82,500

90,000

90,000

Blue Mountains3

2,890

0

2,350

2,460

Total

2,767,150

184,250

1,660,570

2,157,440

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.

Breakdown of storage volumes at the beginning and end of the 2010–11 year for storages not managed by Sydney Catchment Authority

Storage reservoir

Managing authority

Total capacity (ML)

Dead storage volume (ML)

Volume (ML)

30 June 2010

Volume (ML)

30 June 2011

Lake Lyell

Delta Electricity

34,192

2,083

10,956

28,500

Lake Wallace

Delta Electricity

4,004

1,798

3,665

3,839

Thomsons Creek Dam

Delta Electricity

27,500

0

9,665

18,961

Pejar

Goulburn Mulwaree Council

9,000

90

2,732

8,857

Sooley

Goulburn Mulwaree Council

6,250

300

5,771

6,103

Farmers Creek No. 2

Lithgow City Council

450

Not available

415

420

Bamarang

Shoalhaven City Council

3,800

100

3,225

3,800

Danjera

Shoalhaven City Council

7,660

2,300

7,660

7,660

Flat Rock Creek

Shoalhaven City Council

400

0

309

309

Bundanoon

Wingecarribee Shire Council

1,170

Not available

1,170

1,170

Medway

Wingecarribee Shire Council

2,046

Not available

2,046

2,046

Total

96,472

6,6711

47,619

81,665

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.

Quantification Approach

Delta Electricity

Data Source

Level monitoring at the storages, radio telemetry system and data spreadsheets.

Provided by

Delta Electricity.

Method

  • 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.


Assumptions, Limitations, Caveats and Approximations

Nil.

Uncertainty Information

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

Goulburn Mulwaree Council

Data Source

Level monitoring at the storages and data spreadsheets.

Provided by

Goulburn Mulwaree Council.

Method

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.

Assumptions, Limitations, Caveats and Approximations

Nil.

Uncertainty Information

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

Lithgow City Council

Data Source

Level monitoring at Farmers Creek No. 2 Reservoir and data spreadsheets.

Provided by

Lithgow City Council.

Method

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

Assumptions, Limitations, Caveats and Approximations

Information on dead storage volume is not available.

Uncertainty Information

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

Shoalhaven City Council

Data Source

Level monitoring at the storages managed by Shoalhaven City Council.

Provided by

Shoalhaven City Council.

Method

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

Assumptions, Limitations, Caveats and Approximations

Nil.

Uncertainty Information

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

Sydney Catchment Authority

Data Source

Level monitoring at storages – visual and hydrometric sensors, daily returns database and storage tables for reservoirs.

Provided by

Sydney Catchment Authority.

Method

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.

Assumptions, Limitations, Caveats and Approximations

Nil.

Uncertainty Information

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%.

Wingecarribee Shire Council

Data Source

Level monitoring at the storages with Vega-type hydrometric sensors linking to council's radio telemetry system and data spreadsheets.

Provided by

Wingecarribee Shire Council.

Method

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.

Assumptions, Limitations, Caveats and Approximations

Information on dead storage volume is not available.

Uncertainty Information

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

Comparative year

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

 

Comparative information from the 2010 Account for line item 1.1

2011 Account line item

2010 Account line item

Value reported in the 2010 Account (ML)

Value reported in the 2011 Account (ML)

Additional information

1.1 Storages

1.1 Storages and reservoirs

1,708,184

1,708,184

Change in line item name