Bulk water storage and supply report - 18 May 2006

During the week approximately 15 millimetres of rainfall was recorded on the Woronora Catchment and 5 millimetres on the Blue Mountains Catchment. The Warragamba, Upper Nepean and Shoalhaven catchments recorded negligible rainfall during the week.

As at 3 p.m. Thursday 18 May 2006, the inflow rate to Warragamba Dam was 20 megalitres per day and to Tallowa Dam was 40 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.

12.5.06

18°C

5.0 mm

1 407 ML

1 108 500 ML

42.9%

Sat.

13.5.06

17°C

3.0 mm

1 376 ML

1 107 000 ML

42.8%

Sun.

14.5.06

22°C

Nil

1 544 ML

1 105 500 ML

42.8%

Mon.

15.5.06

21°C

26.0 mm

1 701 ML

1 104 000 ML

42.7%

Tue.

16.5.06

18°C

0.6 mm

1 364 ML

1 102 500 ML

42.7%

Wed.

17.5.06

20°C

Nil

1 321 ML

1 101 000 ML

42.6%

Thu.

18.5.06

21°C

Nil

1 429 ML

1 099 500 ML

42.5%

 

Total supply for the week

10 143 ML

Average daily supply during week

1 449 ML

Volume pumped from Shoalhaven for the week

50 ML

Net weekly storage change (megalitres)

-11 210 ML

Net weekly storage change (percentage)

-0.5%

 

Available Water Storage as at 18 May 2006

Storage

Full Operating Storage (ML)

Storage Level (m)

Available Storage (ML)

Available Storage (%)

Net Weekly Change (ML)

Cataract

94,300

- 10.19

30,730

32.6

-870

Cordeaux

93,640

- 7.88

45,540

48.6

-1,170

Avon

146,700

- 10.26

54,960

37.5

-880

Nepean

69,810

- 12.12

37,300

53.4

-110

Woronora

71,790

- 19.26

22,670

31.6

-160

Warragamba

2,027,000

- 19.24

870,550

42.9

-7,090

Prospect

8,870

- 1.16

3,130

35.3

-50

Wingecarribee

24,100

- 2.13

15,250

63.3

-70

Fitzroy Falls

10,000

- 0.90

5,530

55.3

-950

Tallowa*

35,300*

- 3.26

11,790*

33.4*

110

Blue Mountains

2,790

 

1,810

64.9

30

Total

2,584,300

 

1,099,260

42.5

-11,210


*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.