Bulk water storage and supply report - 14 September 2006

During the week the following rainfall (approximately) was recorded in the catchments:

  • Warragamba - 15 mm
  • Upper Nepean - 90 mm
  • Woronora - 110 mm
  • Shoalhaven - 40 mm
  • Blue Mountains - 50 mm.

As at 3 p.m. 14 September 2006, the inflow rate to Warragamba Dam including Shoalhaven transfers was 1700 megalitres per day and to Tallowa Dam was 1500 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.

8.9.06

18°C

1.0 mm

1 321 ML

1 055 500 ML

40.8%

Sat.

9.9.06

18°C

20.0 mm

1 235 ML

1 055 500 ML

40.8%

Sun.

10.9.06

17°C

18.0 mm

1 353 ML

1 060 000 ML

41.0%

Mon.

11.9.06

17°C

30.0 mm

1 400 ML

1 070 000 ML

41.4%

Tue.

12.9.06

19°C

15.0 mm

1 201 ML

1 080 000 ML

41.8%

Wed.

13.9.06

19°C

1.0 mm

1 197 ML

1 084 000 ML

41.9%

Thu.

14.9.06

21°C

Nil

1 294 ML

1 087 500 ML

42.1%

 

Total supply for the week

9 001 ML

Average daily supply during week

1 286 ML

Volume pumped from Shoalhaven for the week

4 150 ML

Net weekly storage change (megalitres)

+ 32 580 ML

Net weekly storage change (percentage)

+ 1.3%

 

Available Water Storage as at 14 September 2006

Storage

Full Operating Storage (ML)

Storage Level (m)

Available Storage (ML)

Available Storage (%)

Net Weekly Change (ML)

Cataract

94,300

- 9.32

34,460

36.5

6,380

Cordeaux

93,640

- 8.26

43,810

46.8

2,360

Avon

146,700

- 11.11

48,820

33.3

2,180

Nepean

69,810

- 4.20

57,110

81.8

1,120

Woronora

71,790

- 17.90

24,950

34.8

4,170

Warragamba

2,027,000

- 20.51

815,480

40.2

3,430

Prospect

8,870

- 0.88

4,480

50.5

490

Wingecarribee

24,100

- 1.28

18,650

77.4

300

Fitzroy Falls

10,000

- 0.07

9,700

97.0

830

Tallowa*

35,300*

- 1.04

27,520*

78.0*

11,220

Blue Mountains

2,790

 

2,480

88.9

100

Total

2,584,300

 

1,087,460

42.1

32,580


*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.