Monthly Water Report
Monthly Water Report
The Monthly Water Report provides a summary of the status of Victoria's water resources and water supplies at the end of the reporting month. It is based on validated water resource information provided by Victoria's 19 Urban and Rural Water Corporations and the Bureau of Meteorology. Each month's report is published online the following month. For detailed, specific and up-to-date information, please contact the relevant Water Corporation or the Bureau of Meteorology. Links to these organisations are located within the Monthly Water Report.
For a weekly snapshot you can now download the Department's Weekly Water Report on the Water Register website.
In August, rainfall was average over most of Victoria, with above average rainfall in small regions of the north and south west. Rainfall was below average across the south-eastern regions of Victoria, with Gippsland recording the driest August since 2007. The state's highest daily rainfall total was recorded at Edi Upper in the King Valley at 62.2mm, a new record for August. Statewide, the rainfall total was 15% below the August average.
Moderate to high streamflows were recorded throughout the North East, Central and South East of the state during August. At the end of August, five sites across the state recorded flows over 100% of the long term average. The highest average flows in the state for August were recorded at Rose River at Matong and Hollands Creek at Kelfeera with flows above 280% of the long term average.
The North West and a small section along the central coast of the state continues to remain dry.
The total volume of water held in Victoria's major storages increased by 7.3% during August, ending the month at 61.5% capacity. Storage volumes rose in almost all of the monitored basins (14 out of 16), with decreases in the Ovens system and Thomson/Macalister system of 8% and 0.9% respectively due to pre-releases in these reservoirs to mitigate flood risk. Increases in storage ranged from 0.9% in the South Gippsland System to 18.9% in the Broken system.
Victoria's regional storages increased by 8.1% to 60.7% of capacity during August 2016. Melbourne's storage levels increased by 2.9% to 66.2% of capacity over the same period. Melbourne's storages are 6.7% lower while regional storages are 3.4% higher than at the same time last year.
Urban water restrictions
There were no towns on water restrictions at the end of August. All Victorian towns are subject to Permanent Water Saving Rules.
The groundwater section of the Monthly Water Report is updated on a quarterly basis. For the last update go to the June 2016 report.
At the end of August 2016, Goulburn-Murray Water had announced seasonal determinations against high-reliability water shares (HRWS) of 51% for the Murray, 46% for the Goulburn, 48% for the Campaspe, 25% for the Loddon, 54% for the Broken and 100% for the Bullarook systems. It had also announced 100% low-reliability water shares (LRWS) for the Bullarook system. No other LRWS allocations have yet been announced.
Seasonal determinations were increased during August for the Werribee and Bacchus Marsh systems by 30% and as at 31 August irrigators had access to 40% HRWS. The Macalister Irrigation District remained at 100% allocation of high-reliability water shares with access to spill entitlement.
On 1 August Coliban Water announced a 50% increase in allocation for its rural customers, bringing allocations up to 100%. This is a result of good rainfall and increases in storage volumes in July.
Restrictions on diversions from unregulated streams
At the end of August 2016, there were five unregulated streams and lakes subject to diversion restrictions, compared to 52 at the end of July. This decrease is due to Southern Rural Water confirming there were no restrictions by the end of August 2016. This time last year, there were 51 waterways subject to restrictions.
Seasonal climate outlook
BoM released its September to November 2016 rainfall outlook on 25 August 2016. The outlook has downgraded the chance of exceeding median rainfall, now predicting a 45-55% chance for a wetter or drier spring for most of the state. Areas along the northern border of Victoria are the most likely to have above median rainfall, with a 55-60% chance.
The Bureau of Meteorology (BoM) released its latest ENSO Wrap-Up on 30 August 2016. It announced that the tropical Pacific Ocean remains in a neutral El Niño–Southern Oscillation (ENSO) state, though a late and weak La Niña remains possible. A negative Indian Ocean Dipole (IOD) continues, but has weakened from record July index values. International climate models are predicting that the negative IOD will weaken during spring and is likely to end in November. This means that its influence on Australia's spring rainfall may not be as strong as it had been during winter, when wetter conditions prevailed in the east.
Sea surface temperatures in the tropical Pacific Ocean are cooler than average, though remain well short of La Niña levels. Cool sub-surface temperatures have eased slowly towards normal. The Bureau's ENSO Outlook remains at La Niña WATCH, which means there is a 50% likelihood of La Niña developing during the second half of 2016, though international climate models suggest neutral to weak La Niña levels for the rest of the year.