Melbourne Water

Weekly Water Report

24 May 2012

Runoff limits decline in dry week

Melbourne’s dam levels experienced a minor decrease in the past week, dropping by 0.1% of capacity.

The net loss of 0.5 billion litres was due to little rainfall over the major catchments, but would have been greater if not for above-average streamflow from previous weeks rain.

The 0.1% loss is a favourable result when compared with the average weekly drop for autumn, 0.3%.

The four major catchments received between 0.6 -3.8 mm of rain, the average being 1mm. This was well below the long-term average for the period, 20mm.

Despite the dry week, streamflow was relatively high, which was a legacy of rain in the previous week.

The 6 billion litres of runoff that entered the dams was 16.2% above the 30-year average for the period (5.2 billion litres).

Water storages are now 64.7% (1,171 billion litres) full, compared with 54.2% (981 billion litres) at the same time last year – a difference of 190 billion litres.

Melburnians used an average of 142 litres of water per person per day over the past week. This is 3 litres each a day more than the previous week.

Information on water restrictions and tips on how to save water are available from water.vic.gov.au or by contacting the government water retailers.

Stage 1 restrictions are currently in place.

Daily residential water use for Melbourne

   PREVIOUS WEEKS
   CURRENT WEEK

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 1997-2012 (opens in a new window)

   2009 - 10     2010 - 11     2011 - 12  
100% capacity = 1,812,175 ML
NB: Prior to 1 July 2010, 100% capacity = 1,810,500 ML

Total system storage (as of 24 May 2012)

Reservoir	Capacity at full supply (ML)	Current Volume (ML)	% Full
Thomson	1,068,000	610,419	57.2%
Cardinia	286,911	214,195	74.7%
Upper Yarra	200,579	122,873	61.3%
Sugarloaf	96,253	94,692	98.4%
Silvan	40,445	36,025	89.1%
Tarago	37,580	20,518	54.6%
Yan Yean	30,266	27,136	89.7%
Greenvale	26,839	20,367	75.9%
Maroondah	22,179	22,259	100.0%
O'Shannassy	3,123	2,872	92.0%
Total	1,812,175	1,171,356	64.6%

Rainfall recorded at the reservoirs

Catchment	18 May - 24 May 2012	Average for the period*	Variation	18 May - 24 May 2011
Thomson	0.6 mm	17.8 mm	96.6% below	19 mm
Upper Yarra	0.8 mm	21.2 mm	96.2% below	23.6 mm
O'Shannassy	1 mm	24.5 mm	95.9% below	30 mm
Maroondah	3.8 mm	20 mm	81.0% below	29 mm

* Average (30 year mean 1982-2011)

Stream flow for the major catchments

Catchment	18 May - 24 May 2012	Average for the period*	Variation	18 May - 24 May 2011
Thomson	2701 ML	2090 ML	29.2% above	4044 ML
Upper Yarra	1383 ML	1000 ML	38.3% above	3118 ML
O'Shannassy	1016 ML	1050 ML	3.2% below	2758 ML
Maroondah	894 ML	1020 ML	12.4% below	2519 ML
Total	5994 ML	5160 ML	16.2% above	12439 ML

* Average (30 year mean 1982-2011)

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

Yarra Catchment
Report for period 17 May - 23 May 2012 (inclusive):

Current seven day rolling average flows for:

• Yarra River @ Yarra Glen = 974.8 ML/day (up 20.1 ML/day from the previous week)
• Yarra River @ Warrandyte = 810.5 ML/day (up 115.1 ML/day from the previous week)
• Little Yarra River @ Yarra Junction = 92.5 ML/day (down 17.4 ML/day from the previous week)
• Woori Yallock Creek @ Yellingbo = 161.9 ML/day (down 15.8 ML/day from the previous week)

Total rainfall for May at:

• Upper Yarra Reservoir is 46.4 mm (long-term May average is 80.8 mm)
• Silvan Reservoir is 71.8 mm (long-term May average is 92.9 mm)

Maribyrnong Catchment
Report for period 17 May - 23 May 2012 (inclusive):

Current seven day rolling average flows for:

• Jacksons Creek @ Sunbury = 9.6 ML/day (up 1.9 ML/day from the previous week)
• Deep Creek @ Bulla = 9.8 ML/day (down 0.2 ML/day from the previous week)
• Maribyrnong River @ Keilor (Brimbank Park) = 30.5 ML/day (up 3.0 ML/day from the previous week)

Total rainfall for May at:

• Rosslyne Reservoir is 21 mm (long-term May average is 51.9 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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