Bulk water storage and supply report - 7 September 2006

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

  • Warragamba - 15 mm
  • Upper Nepean - 48 mm
  • Woronora - 95 mm
  • Shoalhaven - 15 mm
  • Blue Mountains - 35 mm.

As at 3 p.m. 7 September 2006, the inflow rate to Warragamba Dam including Shoalhaven transfers was 830 megalitres per day and to Tallowa Dam was 1000 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.

1.9.06

21°C

Nil

1 312 ML

1 058 000 ML

40.9%

Sat.

2.9.06

23°C

Nil

1 302 ML

1 056 500 ML

40.9%

Sun.

3.9.06

28°C

Nil

1 510 ML

1 055 000 ML

40.8%

Mon.

4.9.06

27°C

Nil

1 618 ML

1 054 000 ML

40.8%

Tue.

5.9.06

21°C

Nil

1 409 ML

1 053 000 ML

40.7%

Wed.

6.9.06

22°C

Nil

1 340 ML

1 051 500 ML

40.7%

Thu.

7.9.06

21°C

107 mm

1 393 ML

1 055 000 ML

40.8%

 

Total supply for the week

9 883 ML

Average daily supply during week

1 412 ML

Volume pumped from Shoalhaven for the week

7 700 ML

Net weekly storage change (megalitres)

- 3 950 ML

Net weekly storage change (percentage)

- 0.2%

 

 

Available Water Storage as at 7 September 2006

Storage

Full Operating Storage (ML)

Storage Level (m)

Available Storage (ML)

Available Storage (%)

Net Weekly Change (ML)

Cataract

94,300

- 10.85

28,080

29.8

-430

Cordeaux

93,640

- 8.78

41,450

44.3

130

Avon

146,700

- 11.42

46,640

31.8

1,600

Nepean

69,810

- 4.60

55,990

80.2

170

Woronora

71,790

- 20.46

20,780

28.9

330

Warragamba

2,027,000

- 20.59

812,050

40.1

-430

Prospect

8,870

- 0.98

3,990

45.0

290

Wingecarribee

24,100

- 1.35

18,350

76.1

320

Fitzroy Falls

10,000

- 0.23

8,870

88.7

560

Tallowa*

35,300*

- 2.60

16,300*

46.2*

-6,540

Blue Mountains

2,790

 

2,380

85.3

50

Total

2,584,300

 

1,054,880

40.8

-3,950


*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.