Bulk water storage and supply report - 4 May 2006

During the week approximately 10 millimetres of rainfall was recorded on the Shoalhaven Catchment and less than 5 millimetres on the Warragamba Catchment. The Woronora, Upper Nepean and Blue Mountains catchments recorded negligible rainfall during the week.

As at 3 p.m. Thursday 4 May 2006, the inflow rate to Warragamba Dam was 30 megalitres per day and to Tallowa Dam was 45 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.

28.4.06

21°C

Nil

1 425 ML

1 132 000 ML

43.8%

Sat.

29.4.06

23°C

Nil

1 461 ML

1 130 500 ML

43.7%

Sun.

30.4.06

25°C

Nil

1 400 ML

1 129 500 ML

43.7%

Mon.

1.5.06

24°C

Nil

1 746 ML

1 127 500 ML

43.6%

Tue.

2.5.06

22°C

Nil

1 504 ML

1 126 000 ML

43.6%

Wed.

3.5.06

23°C

Nil

1 350 ML

1 124 000 ML

43.5%

Thu.

4.5.06

26°C

Nil

1 585 ML

1 122 000 ML

43.4%

 

Total supply for the week

10 471 ML

Average daily supply during week

1 496 ML

Volume pumped from Shoalhaven for the week

50 ML

Net weekly storage change (megalitres)

-12 010 ML

Net weekly storage change (percentage)

-0.5%

 

Available Water Storage as at 4 May 2006

Storage

Full Operating Storage (ML)

Storage Level (m)

Available Storage (ML)

Available Storage (%)

Net Weekly Change (ML)

Cataract

94,300

- 9.78

32,450

34.4

-1,130

Cordeaux

93,640

- 7.38

47,900

51.2

-1,160

Avon

146,700

- 9.99

56,960

38.8

-890

Nepean

69,810

- 12.01

37,540

53.8

-80

Woronora

71,790

- 19.01

23,080

32.1

-210

Warragamba

2,027,000

- 18.89

886,060

43.7

-8,000

Prospect

8,870

- 1.12

3,320

37.4

-100

Wingecarribee

24,100

- 2.08

15,440

64.1

-80

Fitzroy Falls

10,000

- 0.84

5,830

58.3

-90

Tallowa*

35,300*

- 3.26

11,770*

33.3*

-190

Blue Mountains

2,790

 

1,800

64.5

-80

Total

2,584,300

 

1,122,150

43.4

-12,010


*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.