Bulk water storage and supply report - 22 June 2006

During the week approximately 35 millimetres of rainfall was recorded on the Woronora Catchment, 10 millimetres on the Upper Nepean and Blue Mountains catchments and 5 millimetres on the Shoalhaven Catchment. The Warragamba Catchment recorded negligible rainfall during the week.

As at 3 p.m. Thursday, 22 June 2006, the inflow rate to Warragamba Dam including Shoalhaven transfers was 360 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.

16.6.06

18°C

Nil

1 317 ML

1 089 500 ML

42.2%

Sat.

17.6.06

18°C

Nil

1 302 ML

1 088 500 ML

42.1%

Sun.

18.6.06

17°C

Nil

1 489 ML

1 087 500 ML

42.1%

Mon.

19.6.06

18°C

Nil

1 519 ML

1 086 500 ML

42.0%

Tue.

20.6.06

17°C

2.0 mm

1 313 ML

1 085 500 ML

42.0%

Wed.

21.6.06

20°C

3.0 mm

1 282 ML

1 084 500 ML

42.0%

Thu.

22.6.06

15°C

14.0 mm

1 288 ML

1 084 000 ML

41.9%

 

Total supply for the week

9 511 ML

Average daily supply during week

1 359 ML

Volume pumped from Shoalhaven for the week

5 200 ML

Net weekly storage change (megalitres)

-6 720 ML

Net weekly storage change (percentage)

-0.3%

 

Available Water Storage as at 22June 2006

Storage

Full Operating Storage (ML)

Storage Level (m)

Available Storage (ML)

Available Storage (%)

Net Weekly Change (ML)

Cataract

94,300

- 10.88

27,970

29.7

-150

Cordeaux

93,640

- 8.60

42,230

45.1

-180

Avon

146,700

- 10.73

51,540

35.1

-720

Nepean

69,810

- 11.16

39,420

56.5

1,620

Woronora

71,790

- 19.76

21,860

30.4

-150

Warragamba

2,027,000

- 19.99

837,730

41.3

-6,420

Prospect

8,870

- 1.16

3,130

35.3

-10

Wingecarribee

24,100

- 1.50

17,730

73.6

1,740

Fitzroy Falls

10,000

- 0.64

6,800

68.0

-630

Tallowa*

35,300*

- 0.25

33,450*

94.8*

-1,850

Blue Mountains

2,790

 

1,930

69.2

30

Total

2,584,300

 

1,083,790

41.9

-6,720


*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.