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

August 2007 was very dry across most of Victoria. Below average to very much below average rainfall was recorded throughout most of the State with the exception of west Gippsland, which recorded rainfall close to the long-term average. Melbourne received just 15.0 mm of rain during the month, which is well below the long-term August average of 57.4 mm. Mean daily maximum temperatures were well above normal across the State. Winter rainfalls were below average in northern Victoria and in the State’s far south-west. Western, Central and south Gippsland districts received average rainfall, whilst record falls in June ensured very much above average winter rainfall was recorded in west and east Gippsland.

Streamflows

Below average rainfall during August lead to a decline in stream levels across the State. At the end of August, streamflows were below 10% of the long-term average for August across the Wimmera, Mallee, Central and upper Northeast districts (more than two-thirds of the State). The Snowy River, downstream of Basin Creek, was recording the highest flow of 51% of the long-term average, whilst streamflows across the rest of the State were tracking well below (<40%) average.

Storage Levels

Storage volumes increased in all of Victoria’s major basins during the month, however inflows to storages have dropped off following the dry conditions. Volumes in the major storages increased by 3.1% to be at 26.0% of capacity. Melbourne Water's storages increased by 2.9%, to finish the month at 38.6% of capacity, whilst Rural Water Authority storages increased by 3.2%, to finish the month at 23.7% of capacity. Storages in the Glenelg-Wimmera Basin rose to 9.4% of capacity, Lake Eildon rose to 21.8% of capacity and Rosslynne Reservoir increased slightly to 5.1% of capacity.

At the end of August 2007, water levels were below average for most of the key groundwater management areas in the State.

Urban Water Restrictions

A number of key changes to towns on restrictions took effect during August 2007. Restrictions were lifted or reduced for a number of towns in Gippsland and north-east Victoria. The total number of Victorian towns on restriction as at 31 August was 376, of which 14 towns are on Stage 1, 13 are on Stage 2, 45 are on Stage 3, 18 on Stage 3a and 286 are on Stage 4 restrictions.

Irrigation Allocations

G-MW made its latest allocation announcement for the 2007/2008 season on 3 September. Allocations increased to 17% on the Goulburn system, 5% on the Murray system and 10% on the Broken system. There is a zero allocation on the Campaspe, Loddon and Bullarook systems. The Goulburn and Murray systems will operate to a 15 March 2008 close. Water on the Broken system is available until 31 October 2007. Improvements in the resource position on these systems will go towards increasing allocations and extending the duration of irrigation supplies. G-MW will provide the next allocation announcement on 17 September 2007.

SRW opened the 2007/08 irrigation season in the Macalister Irrigation District on 15 August with an allocation of 100%. Off-quota water is available and should continue through spring. In the south-east, Blue Rock Lake increased to 70.2% of capacity. Southern Rural Water licence holders downstream are currently able to pump from unregulated flows; a formal allocation for the season will be announced once unregulated flows drop away. In the south-west, SRW’s share of the Werribee Basin storages rose slightly to 11.2% of capacity. The temporary seasonal allocation for 2007/08 remains at 0% water right and 100% domestic and stock. Storage volumes in Rosslynne Reservoir are also low at 5.1% of capacity. With inflows well below average, SRW irrigators and diverters face another season of low allocations in these systems. 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 during August reflected continued good streamflows in the State’s north east and reduced flows in central Victoria. At the end of August, diversions from a total of 114 streams and lakes across the State were subject to some form of restriction (compared with 118 streams at the end of July 2007).

Seasonal Climate Outlook

The Bureau of Meteorology’s outlook for total spring rainfall generally shows no strong swings in the odds towards wetter or drier conditions in south-east Australia. However, there is a moderate shift in the odds favouring a drier than average spring in south-west Victoria and south Gippsland. Since late July there has been a gradual strengthening of most indicators to near La Niña thresholds. However computer models indicate that a further strengthening is unlikely. Historically, most significant La Niña events are firmly established by winter’s end.