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.

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

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

As at 31 March seasonal allocation determination for high reliability water entitlements increased to 100% for the Goulburn and Loddon systems respectively, and to 35% for the Broken system. In Southern Victoria, seasonal allocation determinations remained the same.

As at 31 March seasonal allocation determinations were increased in the GWMWater system to 55% and remained the same and Coliban Water systems

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

Water corporation





Goulburn Murray Water




Latest Announcement
15 March 2019













Bullarook (Newlyn & Hepburn)



Southern Rural Water

Macalister Irrigation District*



Latest Announcement
26 March 2019

Werribee/ Bacchus Marsh District



Latest Announcement
26 March 2019

GWMWaterWimmera-Mallee Pipeline Product55%

Latest Announcement 8 March 2019

Coliban Water

Coliban Rural System


Opening announcement
1 July 2018

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

The Northern Victorian Resource Manager (GMW) 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.

In March, minor seasonal allocation increases were made against high reliability water shares (HRWS) for Goulburn, Loddon and Broken systems. Campaspe and Murray HRWS were already at 100% allocation and low reliability water shares remained at 0%.

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

The full seasonal determination outlook for northern Victoria is available at:

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 (NVRM) 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 next risk of spill will be declared on 1 July 2019 and will refer to the 2019-20 water year.

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 released the first seasonal outlook for 2019-20 seasonal determinations on 15 February 2019.

Delivery of carryover:

  • certain for Murray, Campaspe, Goulburn and Loddon Systems,
  • dependent on more inflows in Broken and Bullarook but will be deliverable early in the season.

Opening season (1 July) allocation forecast:

  • Likely to be 0% for Broken, Bullarook,
  • Could be 0% for Murray and Loddon, 6% for Goulburn if dry conditions continue,
  • Only system with potential to start of 100% is Campaspe if wet conditions occur.

A repeat of 2018/19 inflows would result in:

  • Goulburn system reaching about 65% by Feb 2020,
  • Murray system reaching about 60% by Feb 2020.

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 (SRW) to undertake this role.

In all instances, SRW 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, is 34,013 ML or 19.1% of capacity at the end of March 2019, and the Thomson entitlement is at 36,446 ML.

The seasonal allocation sits at 100% of HRWS for MID, Thomson and Macalister River and Rainbow Creek customers and 34% of low reliability water shares for MID customers as at end of March 2019.

Next announcement 9 April 2019.

Werribee and Bacchus Marsh systems

Southern Rural Water’s share of the Werribee Basin storages is 33% as at end of March 2019.

The seasonal determination sits at 40% HRWS for Werribee and Bacchus Marsh as at end of March 2019.

Next announcement 9 April 2019.

In the role of Storage Manager, GWMWater 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.

GWMWater 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.

GWMWater 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 8 March GWMWater announced an increase to Wimmera-Mallee allocations. The Wimmera-Mallee Pipeline Product allocation increased to 55%. The next allocation assessment will be announced 5 April 2019.

The Coliban Rural System provides untreated water to approximately 1,500 rural licence holders via 550 kilometres 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 2018.