Bulk water storage and supply report - 13 July 2006

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

As at 3 p.m. Thursday, 13 July 2006, the inflow rate to Warragamba Dam including Shoalhaven transfers was 500 megalitres per day and to Tallowa Dam was 410 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.

7.7.06

19°C

Nil

1 286 ML

1 079 000 ML

41.8%

Sat.

8.7.06

18°C

Nil

1 265 ML

1 078 000 ML

41.7%

Sun.

9.7.06

18°C

Nil

1 472 ML

1 077 000 ML

41.7%

Mon.

10.7.06

17°C

Nil

1 449 ML

1 076 000 ML

41.6%

Tue.

11.7.06

20°C

Nil

1 270 ML

1 075 000 ML

41.6%

Wed.

12.7.06

23°C

Nil

1 295 ML

1 074 000 ML

41.5%

Thu.

13.7.06

18°C

Nil

1 356 ML

1 073 000 ML

41.5%

 

Total supply for the week

9 393 ML

Average daily supply during week

1 342ML

Volume pumped from Shoalhaven for the week

3 650 ML

Net weekly storage change (megalitres)

-6 260 ML

Net weekly storage change (percentage)

-0.3%

 

Available Water Storage as at 13 July 2006

Storage

Full Operating Storage (ML)

Storage Level (m)

Available Storage (ML)

Available Storage (%)

Net Weekly Change (ML)

Cataract

94,300

- 10.94

27,720

29.4

-170

Cordeaux

93,640

- 8.80

41,360

44.2

-350

Avon

146,700

- 11.02

49,460

33.7

-710

Nepean

69,810

- 7.93

47,150

67.5

2,410

Woronora

71,790

- 20.05

21,410

29.8

-200

Warragamba

2,027,000

- 20.34

822,750

40.6

-4,710

Prospect

8,870

- 1.18

3,060

34.5

-70

Wingecarribee

24,100

- 1.45

17,970

74.6

-40

Fitzroy Falls

10,000

- 1.04

4,850

48.5

-2,980

Tallowa*

35,300*

+ 0.01

35,300*

100.0*

520

Blue Mountains

2,790

 

2,000

71.7

40

Total

2,584,300

 

1,073,030

41.5

-6,260


*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.