1 April 2011
Rain Takes Edge off Typical March Storage Drop
Key Points
- Drop in dam levels less severe than March average
- Rain and runoff above average
- Thomson recovery continues
Melbourne’s dam levels decreased by far less than usual in March thanks to unseasonably high rainfall and runoff.
Storages started March at 54.2% and ended the month at 53.7% - a net decrease of 9 billion litres. The 0.5% drop is a welcome result in a month when storages normally fall by 2.2%.
The wet weather that prevailed for most of summer continued in March, with the major catchments receiving 87mm (39% above average). With the catchments already damp much of the rain ended up as runoff into the major harvesting dams, which had 25 billion litres of inflow (96% above average).
Storage levels are now just over double the all-time low of around 25% they hit in mid-2009, but are still relatively low in historical terms. The pre-drought (before 1997) average storage level for this time of year was 76%.
Manager of Water Supply, John Woodland, said with many of the city’s smaller dams close to full, the continued storage recovery in 2011 depended on rainfall over the catchment that feeds the Thomson Dam, by far the system’s largest storage.
“Our smaller dams continued to meet Melbourne’s water needs in March, acting like our daily withdrawal account, while the Thomson racked up further savings for our future needs,” said Mr Woodland.
“The Thomson gained about 6 billion litres in March, which is small bonus for what’s usually a dry month, but still has room for about 650 billion litres, so our focus will continue to be on its recovery.
“One of the benefits of a damp March is the catchments are wetter than they’d normally be at this time of year. It’s a good foundation, but any boost to dam levels will rely on more rain in coming weeks and months,” he added.
Bureau of Meteorology climate modelling suggests the La Nina weather pattern - a key factor in recent unseasonal rainfall - will continue to weaken, with a return to neutral conditions by winter.
Total water consumption (residential, business and industry) in March was 3.7% lower than the same period in 2010. The Victorian Government this week announced that Stage 2 water restrictions will remain in place across Melbourne until at least the end of spring this year.
Media Contact: Nicolas McGay (03) 9235 2278; 0438 981 836
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