Bulk water storage and supply report - 24 August 2006

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

As at 3 p.m. 24 August 2006, the inflow rate to Warragamba Dam including Shoalhaven transfers was 580 megalitres per day and to Tallowa Dam was 310 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.

18.8.06

25°C

Nil

1 285 ML

1 069 500 ML

41.4%

Sat.

19.8.06

23°C

Nil

1 297 ML

1 068 500 ML

41.3%

Sun.

20.8.06

20°C

Nil

1 452 ML

1 068 000 ML

41.3%

Mon.

21.8.06

21°C

Nil

1 647 ML

1 067 000 ML

41.3%

Tue.

22.8.06

21°C

Nil

1 368 ML

1 066 000 ML

41.2%

Wed.

23.8.06

22°C

Nil

1 293 ML

1 065 000 ML

41.2%

Thu.

24.8.06

22°C

1.0 mm

1 391 ML

1 064 000 ML

41.2%

 

Total supply for the week

9 733 ML

Average daily supply during week

1 390 ML

Volume pumped from Shoalhaven for the week

7 700 ML

Net weekly storage change (megalitres)

  -6 230 ML

Net weekly storage change (percentage)

- 0.2%

 

Available Water Storage as at 24 August 2006

Storage

Full Operating Storage (ML)

Storage Level (m)

Available Storage (ML)

Available Storage (%)

Net Weekly Change (ML)

Cataract

94,300

- 10.76

28,440

30.2

40

Cordeaux

93,640

- 8.82

41,300

44.1

-60

Avon

146,700

- 11.55

45,740

31.2

-620

Nepean

69,810

- 5.58

53,290

76.3

2,460

Woronora

71,790

- 20.58

20,600

28.7

-210

Warragamba

2,027,000

- 20.53

814,620

40.2

-2,570

Prospect

8,870

- 1.04

3,700

41.7

-80

Wingecarribee

24,100

- 1.42

18,060

74.9

-150

Fitzroy Falls

10,000

- 0.21

8,950

89.5

470

Tallowa*

35,300*

- 1.14

26,780*

75.9*

-5,520

Blue Mountains

2,790

 

2,300

82.4

10

Total

2,584,300

 

1,063,780

41.2

-6,230


*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.