Bulk water storage and supply report - 5 October 2006

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

As at 3 p.m. 5 October 2006, the inflow rate to Warragamba Dam including Shoalhaven transfers was 120 megalitres per day and to Tallowa Dam was 200 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.

29.9.06

22°C

Nil

1 434 ML

1 080 500 ML

41.8%

Sat.

30.9.06

25°C

Nil

1 400 ML

1 079 500 ML

41.8%

Sun.

1.10.06

21°C

Nil

1 506 ML

1 078 000 ML

41.7%

Mon.

2.10.06

21°C

Nil

1 624 ML

1 076 500 ML

41.7%

Tue.

3.10.06

29°C

0.2 mm

1 442 ML

1 075 000 ML

41.6%

Wed.

4.10.06

21°C

Nil

1 303 ML

1 073 500 ML

41.5%

Thu.

5.10.06

23°C

Nil

1 422 ML

1 071 500 ML

41.5%

 

Total supply for the week

10 130 ML

Average daily supply during week

1 447 ML

Volume pumped from Shoalhaven for the week

4 100 ML

Net weekly storage change (megalitres)

- 9 510 ML

Net weekly storage change (percentage)

- 0.3%

 

Available Water Storage as at 5 October 2006

Storage

Full Operating Storage (ML)

Storage Level (m)

Available Storage (ML)

Available Storage (%)

Net Weekly Change (ML)

Cataract

94,300

- 9.38

34,190

36.3

130

Cordeaux

93,640

- 8.23

43,940

46.9

-50

Avon

146,700

- 10.60

52,470

35.8

1,010

Nepean

69,810

- 5.23

54,240

77.7

-990

Woronora

71,790

- 18.10

24,610

34.3

-200

Warragamba

2,027,000

- 20.83

801,950

39.6

-6,250

Prospect

8,870

- 0.92

4,280

48.3

0

Wingecarribee

24,100

- 1.46

17,910

74.3

190

Fitzroy Falls

10,000

- 0.53

7,340

73.4

-1,070

Tallowa*

35,300*

- 0.93

28,360*

80.3*

-2,230

Blue Mountains

2,790

 

2,320

83.2

-50

Total

2,584,300

 

1,071,610

41.5

-9,510


*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 March 2007.

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.