Bulk water storage and supply report - 17 August 2006

Negligible rainfall was recorded on the SCA’s catchments during the week.

As at 3 p.m. 17 August 2006, the inflow rate to Warragamba Dam including Shoalhaven transfers was 660 megalitres per day and to Tallowa Dam was 450 megalitres per day.

Date

24 hours to 8 a.m.

As at 3 p.m.

Sydney Max. Temp.

Sydney Rainfall

Bulk Water Supply

Available Storage

% Storage

Fri.

11.8.06

17°C

Nil

1 315 ML

1 073 500 ML

41.5%

Sat.

12.8.06

19°C

Nil

1 337 ML

1 073 500 ML

41.5%

Sun.

13.8.06

20°C

Nil

1 377 ML

1 073 000 ML

41.5%

Mon.

14.8.06

20°C

Nil

1 542 ML

1 072 500 ML

41.5%

Tue.

15.8.06

22°C

Nil

1 354 ML

1 071 500 ML

41.5%

Wed.

16.8.06

21°C

16.0 mm

1 400 ML

1 070 500 ML

41.4%

Thu.

17.8.06

20°C

Nil

1 307 ML

1 070 000 ML

41.4%

 

Total supply for the week

9 633 ML

Average daily supply during week

1 376 ML

Volume pumped from Shoalhaven for the week

7 300 ML

Net weekly storage change (megalitres)

  - 3 360 ML

Net weekly storage change (percentage)

- 0.1%

 

Available Water Storage as at 17 August 2006

Storage

Full Operating Storage (ML)

Storage Level (m)

Available Storage (ML)

Available Storage (%)

Net Weekly Change (ML)

Cataract

94,300

- 10.77

28,400

30.1

80

Cordeaux

93,640

- 8.80

41,360

44.2

0

Avon

146,700

- 11.46

46,360

31.6

-770

Nepean

69,810

- 6.50

50,830

72.8

2,690

Woronora

71,790

- 20.44

20,810

29.0

-170

Warragamba

2,027,000

- 20.47

817,190

40.3

-1,710

Prospect

8,870

- 1.02

3,800

42.8

60

Wingecarribee

24,100

- 1.39

18,210

75.6

-320

Fitzroy Falls

10,000

- 0.31

8,480

84.8

-550

Tallowa*

35,300*

- 0.40

32,300*

91.5*

-2,710

Blue Mountains

2,790

 

2,290

82.1

40

Total

2,584,300

 

1,070,030

41.4

-3,360


*NOTE: The "full operating storage" for Tallowa Dam refers only to the amount of water in the dam that is available to be transferred to Sydney and the Illawarra.  When full, the dam can hold 90,000 ML but only 35,300 ML is available to be transferred.

Other water from Tallowa Dam is provided to Shoalhaven City Council for supply to local communities.  Water is also released from the dam as environmental flows for the Shoalhaven River.

 

‘Expanded storage’ levels

On Saturday 15 April 2006, the SCA reached a major milestone in our deep-water storage projects when a water supply access point was created at the base of Warragamba Dam.

Combined, the deep storage projects at Warragamba and Nepean dams add around six months of water supply to the system for use in the present drought. They also add about 40 billion litres a year to the available supply. The SCA will complete the final stages of the projects between now and August this year.

The establishment of the new access point in the Warragamba Dam wall represents the major engineering milestone in these projects.  As a result, we can now report available storage against the volume of the expanded system.  All reports will now relate to the expanded system.

The Government’s Metropolitan Water Plan February 2006 Progress Report uses this expanded storage level to determine the trigger points for further drought management actions:

  • Around 40 per cent of the expanded supply system is the trigger for moving forward with the construction of borefields to access groundwater;
  • Around 30 per cent of the expanded supply system is the trigger for moving forward with the construction of a desalination plant.