Seasonal allocation determinations are made by the respective water corporation resource managers and are made effective in the Victorian Water Register by the Department Environment, Land, Water and Planning (DELWP).

Goulburn-Murray Water is the Resource Manager in northern Victoria and makes seasonal allocation determinations for all regulated river systems. These include the Murray, Goulburn, Loddon, Broken, Campaspe, Ovens, and Bullarook regulated systems.

Southern Rural Water is the Resource Manager in the Thomson/Macalister and Bacchus Marsh/Werribee water systems.

Grampians Wimmera Mallee Water is the Storage Manager for the Wimmera-Glenelg system and Coliban Water manages the Coliban Rural System.

As at end December 2019, allocations in the northern systems increased in the Murray, Goulburn, Loddon and Campaspe systems. The Broken System remained at 0% and Bullarook at 100%. Allocations for high-reliability water shares remained at 100% in the Macalister Irrigation District, and 20% of allocation for low reliability water shares was made available. Allocations for low and high reliability water shares remained the same in the Werribee/Bacchus Marsh district. The Wimmera-Mallee Pipeline Product also increased in the north-west to 36%.

Visit the Water Register website for more information on seasonal allocation determinations.

The seasonal determination status for all systems at the end of December 2019 is shown in the table below.

Water corporation


High reliability water shares

Low reliability water shares


Goulburn Murray Water




Announcement 16 December 2019













Bullarook (Newlyn & Hepburn)



Southern Rural Water

Macalister Irrigation District*



Announcement 17 December 2019

Werribee/ Bacchus Marsh District



Grampians Wimmera Mallee Water

Wimmera-Mallee Pipeline Product


Announcement 6 December 2019

Coliban Water

Coliban Rural Licenses


Announcement 1 July 2019

*Includes private diverters on Thomson and Macalister Rivers and Rainbow Creek.

The Northern Victorian Resource Manager (Goulburn-Murray Water) makes seasonal allocation determinations and outlooks on the first and 15th of each month (or on the next working day if those days fall on a public holiday). However, if the seasonal determination is at 100% for all systems, announcements are just made on the 15th of each month with the last announcement being made on 1 April.

The first update for the 2019-20 season in Northern Victoria was made on 1 July 2019. As at 16 December, allocations for high-reliability water shares (HRWS) increased in four systems, up to 56% for the Murray, 64% for the Goulburn and Loddon, and 63% for the Campaspe system. Bullarook systems opened at 100% for the year and the Broken system remained at 0%. All low-reliability water shares (LRWS) remained at 0%, except for Bullarook which also opened at 100%.

For more information on how seasonal allocation determinations work in northern Victoria go to:

Risk of spill update

Goulburn-Murray Water is responsible for making a declaration of low risk of spill for the Murray, Goulburn and Campaspe regulated systems, taking into account how full the dams are and the range of possible future inflows under prevailing climatic and catchment conditions. The risk of spill relates to the availability of water in spillable water accounts and does not refer to flood risks downstream of storages.

The Northern Victoria Resource Manager had previously declared a low risk of spill for all systems with spillable accounts. All allocation in spillable accounts had been made available accordingly.

The risk of spill was declared on 1 July 2019 for the Murray, Campaspe and Goulburn systems:

  • Murray system – 7.0%
  • Campaspe system – 7.3%
  • Goulburn system – 0%

For more information about the ‘risk of spill’ visit the NVRM website and the Water Register’s website

2019-20 Resource Outlook

New guidelines recommend the use of climate behaviour post July 1975 to assess resource availability under the effects of climate change. During 2018/19, the Resource Manager is transitioning to the recommended climate behaviour for the seasonal determination outlooks.

The Northern Resource Manager updated the outlook for 2019-20 seasonal determinations on 16 December 2019. If conditions remain dry through to February 2020, expect seasonal determinations for HRWS to reach

  • 62% for Murray
  • 67% for Goulburn and Loddon
  • 67% for Campaspe
  • 0% for Broken

For more information go to the NVRM outlook website.

The Southern Rural Water Resource Manager makes seasonal allocation determinations for all regulated river systems in Southern Victoria. These include the Thomson/Macalister and Werribee/Bacchus Marsh regulated systems. The Minister for Water appointed Southern Rural Water to undertake this role.

In all instances, Southern Rural Water announce season opening allocations on 1 July and only publicly announce their determinations if there has been an increase in allocations.

For the Werribee/Bacchus Marsh regulated system seasonal allocations are reviewed fortnightly through the water year. For the Thomson/Macalister system, seasonal allocations are announced fortnightly until high reliability water shares have reached 100%. Once high reliability allocations reach 100%, no further determinations are made until the end of the spill period which is deemed to be 15 December. From 15 December, seasonal allocations are reviewed fortnightly until 1 May.

Macalister Irrigation District (MID)

Lake Glenmaggie, the principal source of water for the MID, was 104,884 ML or 59% of capacity at the end of December 2019, and the Thomson entitlement is at 38,310 ML.

The 2019-20 irrigation season opened on 1 July. The seasonal allocation is at 100% of HRWS for MID, Thomson and Macalister River and Rainbow Creek customers and 20% of allocation for low reliability water shares was made available as at end of December 2019.

Werribee and Bacchus Marsh systems

Southern Rural Water’s share of the Werribee Basin storages is 63.1% as at end of December 2019.

As at end December 2019, the seasonal determination remained unchanged with 100% for high-reliability water shares and 60% for low-reliability water shares.

In the role of Storage Manager, Grampians Wimmera Mallee Water acts independently to manage water resources on behalf of all Wimmera-Glenelg entitlement holders. The role includes allocating available water according to set rules, keeping record of all water delivered and operating the system in the most efficient and timely way possible.

Grampians Wimmera Mallee Water undertakes resource assessments every month to determine the amount of water that can be made available to entitlement holders. These monthly assessments result in a formal announcement on water allocations.

Grampians Wimmera Mallee Water also keeps record of the amount of water delivered to each entitlement holder. From time to time the Storage Manager may also make other announcements, such as declaring a low risk of spill.

Go to the storage manager website for more information.

On 6 December 2019 Grampians Wimmera Mallee Water announced an increase (from 35% to 36%) to the Wimmera-Mallee Pipeline Product allocations.

The Coliban Rural System provides untreated water to approximately 1,500 rural licence holders via 550 kilometers of channels and pipelines. Go to their website for more information on the rural system.

Coliban Water announced an opening allocation of 100% on 1 July 2019.