The Monthly Water Report provides a statewide monthly summary of the status of water resources and water supplies. Each month's report is published online towards the end of the following month. It is based on data provided by Victoria's 19 urban and rural water corporations.

Rainfall

Most of Victoria received average rainfall in December, however parts of the northeast, central and East Gippsland regions received less than the December average.

Streamflows

At the end of December, streamflows recorded at 15 of 16 stations in central, north and north west Victoria were less than 10% of the long-term December average. This includes six stations that recorded no flows. Across the rest of Victoria, another 12 stations recorded flows between 10 and 59% of the long-term December average.

The highest flow for December was recorded at the Merri River at Woodford, which was 60% of the long-term December average.

Storage Volumes

The total volume in the state’s major storages decreased by 2.0% to 26.1% of capacity.

Melbourne's storages are holding 37.5% of capacity which is 0.5% lower than at the end of November.  The major regional water storages decreased by 2.2% to 24.5% of capacity at the end of December.

Restrictions on Urban Water Supplies

Coliban Water reduced Stage 4ex restrictions for Castlemaine, Kyneton and surrounding towns to Stage 3 on 1 December.

Grampians Wimmera Mallee Water reduced Stage 3 restrictions for customers supplied by the Murray system to Stage 1 on 9 December. This included towns and rural customers on the Northern Mallee and Cannie Ridge Pipelines and Supply System 5 of the Wimmera Mallee Pipeline.

At the end of December, 266 Victorian towns were on restrictions, which is significantly lower than the same time last year when 334 towns were on restrictions.

Irrigation Allocations

At the end of December, G-MW allocations for high-reliability water shares (HRWS) on the Murray and Goulburn systems were at 60% and 49% respectively.  An opening allocation of 6% for HRWS was announced for the Bullarook Creek system on 15 December. Allocations for all other northern systems remained at 0%.

G-MW released the final outlook for the 2009/10 season on 16 November. Under average inflow conditions, the Murray system would receive 77% and the Goulburn system 59% for HRWS on 15 February. The Broken system would receive a 3% allocation under average conditions, however all other systems would remain on 0% at 15 February. G-MW will make the next allocation announcement on 4 January.

The allocations for the Coliban Rural System and the Wimmera-Mallee irrigation supply system remain at 0%.

In southern Victoria, the seasonal allocation for the Werribee and Bacchus Marsh irrigation districts was increased to 10% of HRWS.

At the end of the month, Lake Glenmaggie was at 82.0% of capacity. Following the end of the spilling season, allocations for the Macalister Irrigation District were increased to 95% for HRWS.

The irrigation share of Blue Rock was 1,426 ML at the end of December.

Restrictions on Unregulated Streams

At the end of December, diversions from a total of 130 unregulated streams and lakes across the state were subject to restrictions. This is lower than the same time last year when 133 streams were on restriction.

Seasonal Climate Outlook

The Bureau of Meteorology released its rainfall outlook for January to March on 21 December. The outlook reports that the odds are between 55 and 65% for above average rainfall from January to March across most of Victoria. However, the Bureau has advised caution as the outlooks produced at this time of year are not as accurate as for other seasons.

In the latest ENSO Wrap-Up issued on 23 December 2009, overall, the Bureau reports mature El Niño conditions, which are likely to result in below average rainfall for southeast Australia through to early 2010. The impact of El Niño on Australian rainfall typically declines after mid to late summer.