Rainfall

The long-term September average was exceeded in parts of north, central and south-west Victoria due to a significant rainfall event over the first weekend of the month. This rare event stemmed from a broad low-pressure system originating in the tropics and caused widespread flooding in the north and west of the state. 

There was little significant rainfall across Victoria throughout the rest of the month. 

Stream flows

Despite significant rainfall and flooding early in the month, streamflows had declined by the end of the September.
Of the 28 representative streamflow gauging stations, only one station in the Ovens catchment recorded flows above the long-term average at the end of the month. 

Storages

The total volume in Victoria’s major storages was 63.6% of total capacity at the end of the September. The volume in the state’s major regional water storages increased by 13.7% to 66.4% of capacity, and Melbourne's storages increased by 5.6% to 46.9%.

Restrictions on Urban Water Supplies

During September, restrictions for Melbourne and Geelong regions were reduced to Stage 2.  Restrictions for towns on Coliban Water’s Loddon system were reduced to Stage 3.  Emergency Stage 4 restrictions were required for Bundalong and Walwa as a result of flooding, however North East Water reinstated permanent water savings rules by the end of the month. North East Water was also able to remove restrictions for Springhurst.

At the end of the month, 238 Victorian towns were on restrictions, which is significantly less than the same time last year when 328 towns were on restrictions.

Irrigation Allocations

G-MW increased allocations for high-reliability water shares (HRWS) for all northern systems during September. At the end of the month, allocations were Murray (94%), Goulburn (67%), Loddon (67%), Campaspe (100%), Broken (100%) and Bullarook (100%). A 100% allocation for low-reliability water shares (LRWS) was announced for the Bullarook system.

G-MW updated its allocation outlook for the 2010/11 season on 15 September. Under average conditions, the allocation on the Goulburn and Murray systems is forecast to be 100% by 15 October.

Coliban Water announced a 70% allocation for its rural system this month.

In southern Victoria, Southern Rural Water increased the allocation for the Werribee and Bacchus Marsh irrigation districts to 63% for HRWS. 

The allocation for HRWS in the Macalister Irrigation District is 90%, however, irrigators were able to access spill entitlement until 24 September.

Restrictions on Unregulated Streams

At the end of September, diversions from a total of 27 unregulated streams and lakes across the state were subject to restrictions. This is significantly less than the same time last year when 121 streams were on restriction.

Seasonal Climate Outlook

The Bureau of Meteorology’s latest rainfall outlook for October to December reports a neutral outlook for most of Victoria, with above average rainfall being equally likely as below average rainfall. However, the odds favour above average rainfall for parts of northern Victoria.

The Bureau reports that the La Niña event has strengthened in the Pacific Ocean, and that a negative Indian Ocean Dipole event has commenced.  The combination of these events suggests above average rainfall in south-eastern Australia is likely.