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

Very dry conditions continued throughout Victoria during October 2007. Below average rainfall totals were recorded in eastern and western Victoria, whilst well below average rainfall totals were recorded in central Victoria. Melbourne received just 17.6 mm of rain during the month, which is well below the long-term October average of 64.0 mm. Mean daily maximum temperatures were about 2 degrees above normal across the State, whilst minimum temperatures were slightly above normal in most Districts.

Streamflows

Continuing warm and dry conditions resulted in a further decline in Victoria’s rivers and streams during October. At the end of the month, rivers and streams located across most of northern, western and central Victoria were recording flows of less than 10% of the long-term average for October.

Storage Levels

Volumes in the major storages throughout the State declined in all but the Upper Murray, Goulburn, Latrobe and Melbourne catchments in October. This is due to declining inflows and the running of channels in irrigation districts. Volumes in the major storages throughout the State decreased by 0.2% to be at 26.7% of capacity. Melbourne Water's storages increased by 0.1% to finish the month at 39.8% of capacity, whilst Rural Water Authority storages decreased by 0.2% to finish the month at 24.3% of capacity. Storages in the Glenelg-Wimmera Basin dropped to 5.7% of capacity, Lake Eildon rose to 23.7% of capacity and Rosslynne Reservoir decreased slightly to 4.9% of capacity.

Urban Water Restrictions

A number of key changes to towns on restrictions took effect during October 2007. Restrictions were lifted or reduced for a number of towns in southern Victoria and north-east Victoria. General exemptions to Stage 4 Water Restrictions have been introduced for all customers supplied from the Murray system, Coliban Water’s Goulburn and Coliban systems, and Barwon Water’s Greater Geelong supply system. The total number of Victorian towns on restriction as at 31 October was 375 of which 65 towns are on Stage 1, 51 are on Stage 2, 12 are on Stage 3, 18 are on Stage 3a, 108 are on Stage 4 with general exemptions and 121 are on Stage 4.

Irrigation Allocations

Allocations continue to be extremely low in northern Victoria due to ongoing dry conditions. Allocations have increased in the Goulburn, Murray, Broken and Campaspe systems. The gravity irrigation seasons have been extended to 15 May 2008 for the Goulburn system and 15 April 2008 for the Murray system. Broken system customers have continuous access to water until 30 November 2007, whilst customers in the Loddon and Campaspe systems have rostered access. There is not enough water in the Bullarook system for an irrigation allocation. Coliban Water’s rural season remained at 30% of licensed volume.

Although flows in the Macalister Basin have dropped off, SRW has made a 100% allocation of high reliability water entitlement and a 5% sales water allocation in the Macalister Irrigation District. In the south-east, licence holders downstream of Blue Rock are currently able to pump from unregulated flows. A formal allocation for the season will be announced once unregulated flows drop away. Allocations of 5% water right and 100% domestic and stock in the Werribee and Bacchus Marsh irrigation districts remains unchanged. Rights to water in the Deutgam Groundwater Management Area remain suspended to protect the resource from seawater intrusion.

Restrictions on Diversions

Changes in restrictions on unregulated streams in Victoria during October generally reflected the diminishing streamflows throughout the State. At the end of October, diversions from a total of 125 streams and lakes across the State were subject to some form of restriction.

Seasonal Climate Outlook

The Bureau of Meteorology’s rainfall outlook for the November to January quarter indicates that the chances of exceeding the three-month median rainfall are between 45 and 60% across most of Victoria. A La Niña event is in progress across the Pacific Basin. Computer models indicate it will persist at least until the early part of 2008. However, this La Niña is late to develop by historical standards. Widespread rainfall over Australia’s eastern half is not as likely to occur under late developing La Niña events. Australia’s climate has also been influenced by the unusually cool ocean temperatures to the north and northwest of the continent. The current pattern is inhibiting the formation of northwest cloud bands, which are the major source of winter and spring rain in central and south-eastern Australia during La Niña years.