Bulk water storage and supply report - 21 September 2006

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

As at 3 p.m. 21 September 2006, the inflow rate to Warragamba Dam including Shoalhaven transfers was 400 megalitres per day and to Tallowa Dam was 500 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.

15.9.06

22°C

Nil

1 294 ML

1 089 500 ML

42.2%

Sat.

16.9.06

23°C

Nil

1 286 ML

1 090 500 ML

42.2%

Sun.

17.9.06

22°C

Nil

1 408 ML

1 090 500 ML

42.2%

Mon.

18.9.06

22°C

Nil

1 597 ML

1 091 000 ML

42.2%

Tue.

19.9.06

26°C

Nil

1 356 ML

1 091 000 ML

42.2%

Wed.

20.9.06

26°C

Nil

1 426 ML

1 090 000 ML

42.2%

Thu.

21.9.06

30°C

Nil

1 431 ML

1 089 500 ML

42.2%

 

Total supply for the week

9 798 ML

Average daily supply during week

1 400 ML

Volume pumped from Shoalhaven for the week

2 800 ML

Net weekly storage change (megalitres)

+ 2 250 ML

Net weekly storage change (percentage)

+ 0.1%

 

Available Water Storage as at 21 September 2006

Storage

Full Operating Storage (ML)

Storage Level (m)

Available Storage (ML)

Available Storage (%)

Net Weekly Change (ML)

Cataract

94,300

- 9.38

34,190

36.3

-270

Cordeaux

93,640

- 8.22

43,990

47.0

180

Avon

146,700

- 10.90

50,320

34.3

1,500

Nepean

69,810

- 4.49

56,290

80.6

-820

Woronora

71,790

- 17.84

25,050

34.9

100

Warragamba

2,027,000

- 20.53

814,620

40.2

-860

Prospect

8,870

- 0.89

4,430

49.9

-50

Wingecarribee

24,100

- 1.41

18,100

75.1

-550

Fitzroy Falls

10,000

- 0.28

8,610

86.1

-1,090

Tallowa*

35,300*

- 0.49

31,670*

89.7*

4,150

Blue Mountains

2,790

 

2,440

87.5

-40

Total

2,584,300

 

1,089,710

42.2

2,250


*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 March 2007.

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.