Bulk water storage and supply report - 25 May 2006

During the week approximately 35 millimetres of rainfall was recorded on the Shoalhaven Catchment, 20 millimetres on the Blue Mountains Catchment and less than 10 millimetres on the Warragamba, Upper Nepean and  Woronora catchments.

As at 3 p.m. Thursday 25 May 2006, the inflow rate to Warragamba Dam was 30 megalitres per day and to Tallowa Dam was 90 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.

19.5.06

23°C

Nil

1 417 ML

1 098 000 ML

42.5%

Sat.

20.5.06

23°C

Nil

1 393 ML

1 096 500 ML

42.4%

Sun.

21.5.06

20°C

Nil

1 471 ML

1 095 000 ML

42.4%

Mon.

22.5.06

19°C

Nil

1 627 ML

1 093 500 ML

42.3%

Tue.

23.5.06

18°C

1.0 mm

1 428 ML

1 092 500 ML

42.3%

Wed.

24.5.06

15°C

3.0 mm

1 293 ML

1 090 500 ML

42.2%

Thu.

25.5.06

21°C

Nil

1 354 ML

1 088 500 ML

42.1%

 

Total supply for the week

9 983 ML

Average daily supply during week

1 426 ML

Volume pumped from Shoalhaven for the week

100 ML

Net weekly storage change (megalitres)

-10 630 ML

Net weekly storage change (percentage)

-0.4%

 

Available Water Storage as at 25 May 2006

Storage

Full Operating Storage (ML)

Storage Level (m)

Available Storage (ML)

Available Storage (%)

Net Weekly Change (ML)

Cataract

94,300

- 10.38

29,950

31.8

-780

Cordeaux

93,640

- 8.09

44,580

47.6

-960

Avon

146,700

- 10.38

54,080

36.9

-880

Nepean

69,810

- 12.16

37,210

53.3

-90

Woronora

71,790

- 19.38

22,470

31.3

-200

Warragamba

2,027,000

- 19.42

862,570

42.6

-7,980

Prospect

8,870

- 1.17

3,080

34.7

-50

Wingecarribee

24,100

- 2.10

15,360

63.7

110

Fitzroy Falls

10,000

- 0.92

5,450

54.5

-80

Tallowa*

35,300*

- 3.22

12,050*

34.1*

260

Blue Mountains

2,790

 

1,830

65.6

20

Total

2,584,300

 

1,088,630

42.1

-10,630


*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.