Melbourne Water

Weekly Water Report

2 February 2012

Good rain and runoff fail to halt dam decline

Above-average rain and runoff were not enough to stop water storages from decreasing for the third week in a row.

The four major catchments received between 10 and 31mm of rain, at an average of 25mm. This was 70% above the 30-year average for the period.

The rain resulted in 5 billion litres of streamflow into the major reservoirs.

This was slightly more than 25% above the average for the period (4 billion litres), but not enough to pay back the water used by Melbourne over the week.

As a consequence, dam levels decreased by 0.2% of capacity, which represents a net loss of 5 billion litres.

Water storages are now 65.2% (1,180.9 billion litres) full, compared with 53.6% (971.5 billion litres) at the same time last year – a difference of 209.4 billion litres.

Residential water use remained high due to some warm weather, particularly earlier in the period.

Melburnians used an average of 196 litres of water per person per day over the past week. This is 3 litres per day less 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 2 February 2012)

Reservoir	Capacity at full supply (ML)	Current Volume (ML)	% Full
Thomson	1,068,000	584,102	54.7%
Cardinia	286,911	208,304	72.6%
Upper Yarra	200,579	165,423	82.5%
Sugarloaf	96,253	95,170	98.9%
Silvan	40,445	34,600	85.5%
Tarago	37,580	21,725	57.8%
Yan Yean	30,266	26,798	88.5%
Greenvale	26,839	20,349	75.8%
Maroondah	22,179	21,718	97.9%
O'Shannassy	3,123	2,754	88.2%
Total	1,812,175	1,180,943	65.2%

Rainfall recorded at the reservoirs

Catchment	27 Jan - 2 Feb 2012	Average for the period*	Variation	27 Jan - 2 Feb 2011
Thomson	26.4 mm	14 mm	88.6% above	0 mm
Upper Yarra	24.6 mm	13.7 mm	79.6% above	0 mm
O'Shannassy	30.8 mm	15.6 mm	97.4% above	0 mm
Maroondah	10.2 mm	18.4 mm	44.6% below	0 mm

* Average (30 year mean 1982-2011)

Stream flow for the major catchments

Catchment	27 Jan - 2 Feb 2012	Average for the period*	Variation	27 Jan - 2 Feb 2011
Thomson	1733 ML	1360 ML	27.4% above	988 ML
Upper Yarra	641 ML	790 ML	18.9% below	846 ML
O'Shannassy	1357 ML	940 ML	44.4% above	1751 ML
Maroondah	1232 ML	830 ML	48.4% above	1200 ML
Total	4963 ML	3920 ML	26.6% above	4785 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 26 January - 1 February 2012 (inclusive):

Current seven day rolling average flows for:

• Yarra River @ Yarra Glen = 549.6 ML/day (down 91.4 ML/day from the previous week)
• Yarra River @ Warrandyte = 322.5 ML/day (down 100.6 ML/day from the previous week)
• Little Yarra River @ Yarra Junction = 69.9 ML/day (down 5.4 ML/day from the previous week)
• Woori Yallock Creek @ Yellingbo = 83.3 ML/day (down 13.5 ML/day from the previous week)

Total rainfall for February at:

• Upper Yarra Reservoir is 13.6 mm (long-term February average is 46.9 mm)
• Silvan Reservoir is 21.2 mm (long-term February average is 49.7 mm)

Total rainfall for January at:

• Upper Yarra Reservoir is 44 mm (long-term January average for 63.2 mm)
• Silvan Reservoir is 65.2 mm (long-term January average is 59.0 mm)

Maribyrnong Catchment
Report for period 26 January - 1 February 2012 (inclusive):

Rosslyne Reservoir
Melbourne Water's Capacity Share of the storage as at 30 January 2012 was 1710 Megalitres (ML)

• Current release from Rosslyne (as at 30 January 2012) to meet bulk entitlement demands = 6.69 ML/day

Current seven day rolling average flows for:

• Jacksons Creek @ Sunbury = 3.8 ML/day (up 1.4 ML/day from the previous week)
• Deep Creek @ Bulla = 0 ML/day (no change from the previous week)
• Maribyrnong River @ Keilor (Brimbank Park) = 3.3 ML/day (up 0.9 ML/day from the previous week)

Total rainfall for February at:

• Rosslyne Reservoir is 0 mm (long-term February average is 42.3 mm)

Total rainfall for January at:

• Rosslyne Reservoir is 6.4 mm (long-term January average for 45.3 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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