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 the State’s 20 urban and rural water corporations.

Rainfall

Rainfall in Victoria was well below average in almost all parts of the State, with the exception of a few "pockets" in Gippsland, where rainfall was close to normal. This below average rainfall has been typical of conditions across much of Australia.

Streamflows

Given the prolonged dry conditions, catchments across the State are very dry, and September rainfalls were insufficient to generate significant runoff. At the end of September, almost three quarters of the State had streamflows that were less than 10% of the long-term average flow for the month, with flows improving in the east of the State but predominantly only into the 10-19% flow range.

Storage Levels

Volumes in the major storages in Victoria reduced further by 1.8% in September compared with an increase of 8.5% at the same time last year. Melbourne Water’s storages reduced by 0.9% to be 45.9% of capacity at the end of the month (13.4% lower than at the same time last year). Rural Water Authority storages decreased by 1.9% to be at 28.4% of capacity (25.1% lower than at the same time last year).

Storages in the Glenelg-Wimmera Basin are at 6.6% of capacity compared with 9% at the same time last year. At the end of the month Lake Eildon was at 20.4% of capacity compared with 44.7% at the same time last year, and Rosslynne Reservoir was at 6.7% of capacity compared with 15.6% at the same time last year.

Urban Water Restrictions

A number of new or increased urban restrictions took effect during September and from 1 October 2006. In mid-September, restrictions were increased from Stage 1 to Stage 2 for 52 towns in Geelong and Bellarine Peninsula. From 1 October, restrictions were increased to Stage 2 for towns supplied from the Loddon system, restrictions were increased to Stage 4 for 38 towns supplied from the Grampians headworks system or the Waranga channel system, and Stage 1 restrictions were introduced for all towns in the Westernport area.

The total number of towns subject to water restrictions as at 1 October 2006 was 220 (compared with 181 at the same time in 2005 and 198 at the end of September 2004). Fifty-three towns are currently subject to low levels (Stage 1) of restriction, 65 towns are on moderate (Stage 2) restrictions and 102 are on high levels (Stages 3 and 4) of restriction.

Irrigation Allocations

Goulburn-Murray Water updated water allocations for northern irrigators for the 2006/07 season on 2 October 2006. Exceptionally dry conditions have been experienced in all systems and all storages remain at very low levels. There is still no allocation for irrigation entitlements in the Campaspe and Loddon systems. The Goulburn system allocation increased during September from 17% to 21%.

In the Murray system, the allocation increased by 8% to be at 93% of Water Right and Licensed Volume. In the Broken system the allocation remains the same at 45% of Licensed Volume. In the Bullarook System, customers supplied from Newlyn Reservoir have an allocation of 36% (an increase of 2%) and the customers supplied from Hepburns Lagoon still have an allocation of 0%.

South of the Divide, because of the low storage situation, irrigation allocations for the 2006/2007 season are very low. In the south-west, allocations are 0% for the Bacchus Marsh Irrigation Area and 5% for the Werribee Irrigation Area. A connection to Western Water’s “Bacchus Marsh to Merrimu pipeline” has been installed to help alleviate the situation for Bacchus Marsh irrigators, while recycled water is available to participating irrigators in the Werribee district (about 50% of growers). Levels in the Deutgam Groundwater Management Area have been declining through 2005/06 season, and in order to protect the resource from seawater intrusion, allocations for the 2006/2007 season are at 25% of licensed volume.

In the east of the State, water availability on the Latrobe system is satisfactory with Blue Rock being at 82.8% of capacity, and an allocation of 100% has been made for diverters from this system. Lake Glenmaggie, which supplies the Thomson-Macalister Irrigation District, is at 37.3% of capacity and irrigation allocations are at 35%. Rosslynne Reservoir is at 6.7% of capacity and the allocation for Southern Rural Water diverters is 5%.

Seasonal Climate Outlook

The Seasonal Outlook released by the Bureau of Meteorology on 26 September 2006 for October to December indicates the chances of above median rainfall are 30-40% across most of Victoria, decreasing to 25-30% over most of the coastal area along the west and south-central coast. Chances rise to 40-50% in the far east of the State. Chances of exceeding median maximum temperatures are over 80% across the State.

The Southern Oscillation Index (SOI), negative for the fourth straight month, rose from −16 in August to -4.6 in September. In addition to the negative SOI, the equatorial Pacific has been warming and the Trade Winds have been weak. These indicators are all consistent with the development phase of an El Niño event, the likelihood of which has risen strongly in the past month.

The continuing dry conditions are resulting in increasing pressures on urban and rural supplies in many parts of the State, and water authorities and Government are developing and implementing (where necessary) contingency plans to manage the situation. Rainfalls over the remainder of spring will be critical in determining the severity of the situation to be managed over the coming summer/autumn period.