Melbourne Water

Weekly Water Report

30 July 2010

1mm of rain but 5 billion litres banked

Melbourne’s dam levels continued to rise in another week with little rain over the catchments.

Storages increased 0.3% since last Thursday, representing a net gain of just over 5 billion litres to the city’s reserves.

The boost came despite major catchments averaging under 1mm of rain (well below the norm of 27mm) and is the result of rain in previous weeks still flowing through the system.

Stream flow remained reasonably strong at more than 8 billion litres, despite the dry conditions – but this was almost 40% below the long term average and 5 billion litres less than the previous week.

Storages are now 35.9% (651 billion litres) full, compared with 27.0% (489 billion litres) at the same time last year – a difference of 162 billion litres.

Low water use helped with this lead, with Melburnians using 134 litres per person, per day – 21 litres below the target.

A 28 day exemption for watering in drought-tolerant lawns will apply in Melbourne from 1 September 2010.

More information on restrictions and tips on how to reach the target are available from Target 155 or by contacting the government water retailers.

Stage 3 restrictions and Target 155 are currently in place.

Daily residential water use for Melbourne

   PREVIOUS WEEKS
   CURRENT WEEK
   TARGET 155

All figures include non-metropolitan supply for Western Water (supplied since March 2000), which are not included in annual Melbourne metropolitan consumption figures.

Melbourne's water storages

View interactive storage graph for 1997-2010 (opens in a new window)

   2008     2009     2010  
100% capacity = 1,812,175 ML
NB: Prior to 1 July 2010, 100% capacity = 1,810,500 ML

Total system storage (as of 29 July 2010)

Reservoir	Capacity at full supply (ML)	Current Volume (ML)	% Full
Thomson	1,068,000	249,752	23.4%
Cardinia	286,911	111,135	38.7%
Upper Yarra	200,579	114,804	57.2%
Sugarloaf	96,253	61,650	64.0%
Silvan	40,445	35,095	86.8%
Tarago	37,580	21,478	57.2%
Yan Yean	30,266	12,750	42.1%
Greenvale	26,839	17,091	63.7%
Maroondah	22,179	13,895	62.6%
O'Shannassy	3,123	3,147	100.0%
Total	1,812,175	640,797	35.4%
Non-catchment sources
Sugarloaf Pipeline Allocation		10,014
Grand Total	1,812,175	650,811	35.9%

Rainfall recorded at the reservoirs

Catchment	23 Jul - 29 Jul 2010	Average for the period*	Variation	23 Jul - 29 Jul 2009
Thomson	0.2 mm	26.7 mm	99.3% below	16.8 mm
Upper Yarra	1 mm	25.7 mm	96.1% below	27.2 mm
O'Shannassy	1 mm	34.6 mm	97.1% below	34.4 mm
Maroondah	2.8 mm	24.5 mm	88.6% below	26.6 mm

* Average (30 year mean 1980-2009)

Stream flow for the major catchments

Catchment	23 Jul - 29 Jul 2010	Average for the period*	Variation	23 Jul - 29 Jul 2009
Thomson	2946 ML	5880 ML	49.9% below	2565 ML
Upper Yarra	1661 ML	3640 ML	54.4% below	1218 ML
O'Shannassy	2350 ML	2340 ML	0.4% above	1491 ML
Maroondah	1441 ML	1950 ML	26.1% below	981 ML
Total	8398 ML	13810 ML	39.2% below	6255 ML

* Average (30 year mean 1980-2009)

Note: These results are preliminary and are validated at the end of the month.

Yarra Catchment
Report for period 22 July - 28 July 2010 (inclusive):

• Current seven day rolling average flows for Yarra River @ Yarra Glen = 661.9 ML/day (down 689.2 ML/day from the previous week)
• Current seven day rolling average flows for Yarra River @ Warrandyte = 247.6 ML/day (down 425.7 ML/day from the previous week)
• Current seven day rolling average flows for Little Yarra River @ Yarra Junction = 79.2 ML/day (down 31.8 ML/day from the previous week)
• Current seven day rolling average flows for Woori Yallock Creek @ Yellingbo = 135.8 ML/day (down 130.0 ML/day from the previous week)
• Total rainfall at Upper Yarra Reservoir for July is 60.2 mm (long-term monthly average for July is 105.2 mm)
• Total rainfall at Silvan Reservoir for July is 71 mm (long-term monthly average for July is 106.8 mm)

Maribyrnong Catchment
Report for period 22 July - 28 July 2010 (inclusive):

Rosslyne Reservoir
Melbourne Water's Capacity Share of the storage as at 26 July 2010 was 39 Megalitres (ML)

• Current release from Rosslyne (as at 26 July 2010) to meet bulk entitlement demands = 0.07 ML/day
• Current seven day rolling average flows for Jacksons Creek @ Sunbury = 9.6 ML/day (down 8.0 ML/day from the previous week)
• Current seven day rolling average flows for Deep Creek @ Bulla = 69 ML/day (down 192.5 ML/day from the previous week)
• Current seven day rolling average flows for Maribyrnong River @ Keilor (Brimbank Park) = 61.1 ML/day (down 111.5 ML/day from the previous week)
• Total rainfall at Rosslyne Reservoir for July is 35 mm (long-term monthly average for July is 56.7 mm)

Note: Passing flows at Keilor, as per the bulk entitlement agreement, require 5.0 ML/day or natural, whichever is the lesser, to be passed at Keilor. Natural flows are based on flows at Deep Ck @ Bulla gauging station.

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