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

Rainfall totals for May were below the long-term averages across most of the state. Western Victoria received average rainfall for May due to a significant rainfall event late in the month.

Parts of the West Gippsland and Central districts received their lowest May rainfall on record.

Streamflows

At the end of the month, streamflows across Victoria had worsened since April due to below average rainfall.

No flows were recorded at 11 of the 28 representative gauging stations at the end of May. Fifteen stations exhibited flows less than 10% of the long-term average for May.

Storage Volumes

The rate of storage level decline across Victoria slowed during May. Storages in some parts of the state began to show small signs of recovery.

This month, the total volume in the state’s major storages remained steady at 12.5% of capacity.

Melbourne's storages decreased by 1.5% over the month to 26.3% of capacity. This is 3.2% lower than at the same time last year. Regional water storages increased by 0.1% to 10.7% of capacity at the end of May.

Restrictions on Urban Water Supplies

North East Water introduced Stage 1 restrictions for Benalla from 6 May, and Stage 4 restrictions for Bundalong from 13 May. Goulburn Valley Water relaxed restrictions at Longwood from Stage 3 to Stage 1 from 11 May 2009.

On 31 May 2009, 341 Victorian towns were on restrictions. Of these, 67 towns were on Stage 1 restrictions, 48 were on Stage 2, 50 were on Stage 3, 19 on Stage 3a, 105 on Stage 4 with general exemptions and 52 on Stage 4. Approximately 170 towns were not on water restrictions but were subject to Permanent Water Saving Rules.

Irrigation Allocations

G-MW made the final allocations for the 2008/09 season on 1 April 2009.

They were 35% on the Murray system, 33% on the Goulburn system and 0% for all other northern systems.

G-MW updated the seasonal allocation outlook for the 2009/10 season on 15 May 2009.  All northern Victorian systems are expected to have zero seasonal allocation on 1 July 2009.  Allocations in the 2009/10 season will depend completely on winter and spring inflows to storages.

Allocations on both the Coliban Rural System and the Wimmera-Mallee irrigation supply system remained at zero per cent during May.

In southern Victoria, the seasonal allocation for the Werribee and Bacchus Marsh irrigation districts remained at 5% of high reliability water share. This allocation applies until 30 June 2009.

At the end of the month, Lake Glenmaggie was at 26.3% of capacity.  The irrigation season for the Macalister Irrigation District closed on 15 May with allocations at 100% for high-reliability water shares and 10% for low-reliability. The irrigation share of Blue Rock was 223 ML at the end of May.

Restrictions on Unregulated Streams

At the end of May, diversions from a total of 190 unregulated streams and lakes across the state were subject to restrictions. This is greater than this time last year when 156 streams were on restriction.

Seasonal Climate Outlook

The Bureau of Meteorology released the rainfall outlook for the period June to August on 26 May 2009. The outlook shows there is a slight shift in the odds favouring drier than normal conditions for the southwest coast of Victoria. The chances of exceeding the median rainfall are between 40% and 45% across most of the state, with between 45% and 55% in East Gippsland and between 35% and 40% along the southwest coast.

The Bureau issued the ENSO Wrap-Up on 21 May 2009. Climate indicators across the equatorial Pacific are currently neutral, although recent trends are consistent with the very early stages of a developing El Niño. All international climate modes predict further warming of the Pacific Ocean SST, with half of the models forecasting the development of El Niño conditions later in 2009. The Indian Ocean Dipole, has become increasingly positive over the last month