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Allocation – Macalister

The allocation for the 2018-19 season for the Macalister Irrigation District is currently:

  • High Reliability 100% 100%
  • Low Reliability 35% 35%

Changes in allocations are announced via this website, SMS and media releases. If there is no change, we do not make any announcements.


Spill entitlement is not currently available.

Thomson River and Rainbow Creek, Nambrok / Denison and Cowwarr Channel, Macalister River

Area Start Date Finish Date
Areas north of the Thomson River, excluding the Thomson River Diverters
Thomson River and Rainbow Creek
Nambrok / Denison and Cowwarr Channel
Macalister River
Estimated total spill usage Maximum volume Remaining volume
62,000 ML 62,000 ML
Allocation method

Seasonal allocations in the Macalister Irrigation Area (MID, Thomson, Macalister River & Rainbow Creek diverters)

A seasonal allocation tells irrigators what percentage of their high and low reliability water shares they can use for the season. It reflects how much water is actually available in storage.

As a general rule, the Macalister Irrigation District (MID) irrigation season begins on 15 August and ends on 15 May. The irrigation season for river diverters begins on 1 July and finishes on 30 June.

Southern Rural Water (SRW) determines the allocation in the Macalister Irrigation Area based on available water.

We announce the starting allocation on 1 July each year, and review it each fortnight during the season.

To receive allocation updates by SMS, email or fax, please contact us.

How we work out the allocations

We divide the irrigation year into three phases:

  • filling
  • spilling
  • emptying

This approach recognises Lake Glenmaggie as an annual storage, and makes all water available for use during the year. The reservoir will generally increase in volume in winter and spring (filling most years) then spill during springtime and gradually empty during late spring, summer and autumn. Because winter and spring inflows are generally enough to fill Lake Glenmaggie, we don’t need to carry over water from one irrigation season to the next.

The diagram below shows the 3 key phases of Lake Glenmaggie’s year:

The filling phase

The filling phase starts at the beginning of the irrigation season.

The spilling phase

The spilling phase begins once Lake Glenmaggie has filled (usually between September and October). The spilling phase ends on 15 December each season. During this time, Southern Rural Water may allocate up to 100% high reliability water shares with the utilisation of the Thomson Drought Reserve. No low reliability water shares (Sales) are available during this period.

The emptying phase

This phase will start when we begin to draw down on the water held in Lake Glenmaggie. Depending on inflows into Lake Glenmaggie during the emptying phase, Southern Rural Water may announce allocation against low reliability water shares.

Maximum efficiency rule

In very dry seasons, the Maximum Efficiency Rule is applied to help secure water supplies by keeping losses to a minimum during the filling and emptying periods. Our planners will schedule water deliveries to maximise efficiency and to conserve the volume of water in storage. This may mean a small change to your requested water order day or time of delivery.

In seasons of low allocation, irrigation rosters may also be introduced to maximise efficiency, so that channel operating losses are reduced. As an example, a channel system may operate for a week and be closed for a week. Customers will be notified well in advance if channel rosters are going to be introduced.

Spill entitlement

Once Lake Glenmaggie spills, all water used from the start of the season is called spill entitlement. As a result, all water that has already been used when spill entitlement is announced will be credited back as “usable allocation”, leaving you with your full seasonal allocation to use.

The process of crediting your usage during the spill period will continue until the maximum communal volume of 62,000 megalitres is reached.

To receive spill entitlement, all water orders must have been both placed and delivery completed, before the spill finishes.
If Lake Glenmaggie doesn’t spill, there will be no spill entitlement and any water used will continue to be deducted from your seasonal allocation.

Thomson Reservoir Drought Reserve

The Thomson Drought Reserve is only used when the allocation is below 100%.

The drought reserve will be used to maximise allocations early in the season, and to provide additional allocation for dry years.
The drought reserve or a proportion of it will remain in the allocation model until 100% is reached using inflows to Lake Glenmaggie and Harvest Rights only. From this point, any allocation of low reliability water will come from further inflows into Lake Glenmaggie

In practice this means that:
1. at the beginning of the season (1 July)
2. at the end of Lake Glenmaggie actually spilling
3. the end of potential spilling period (15 December)

the entire entitlement shall be applied to the allocation model. This is likely to mean:

When … Then …
the volume is less than 20,000ML the maximum allocation will be 90%
the volume is greater than 20,000ML, but less than 30,000ML the maximum allocation will be 95%
the volume is greater than 30,000ML the maximum allocation will be 100%

Water releases shall be managed to ensure the maximum volume of water is maintained in the entitlement – i.e. river harvest rights and releases from Lake Glenmaggie will be the first sources used to meet demand.

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WaterMatch - online trading

Watermatch is a free online service, designed to help people trade water.

Once you have registered, you can advertise to buy or sell water.

Depending on the water that you wish to trade, choose from the Groundwater, Surface Water (rivers and creeks) and Irrigation District forum.

Select a new topic to create your ad. Your ad can be to buy or sell water, and must describe the source of your water, quantity of water you want to buy or sell, how long you want to trade for and your contact details. If you are happy to put a buying or selling price, this can be included here too.

If you want to respond to an ad, you can use the email link or contact the advertiser direct.

It is an online trading forum, and can also be used by people who are not on the internet, with help from our staff.

Watermatch allows you to register your interest in either buying or selling water in southern Victoria.

  • the Macalister, Werribee and Bacchus Marsh Irrigation District
  • Groundwater systems in southern Victoria
  • Rivers and creek systems in southern Victoria (other than those managed by Melbourne Water around the Port Phillip region).

Who can use it?
Anyone can use watermatch. You may be an existing licence holder who wants to sell water, or buy more water.

You may not currently have a licence, but you want to buy water in the region.

How does it work?

  • click here to enter Watermatch
  • register as a user (a very simple process)
  • go to the system or district you are interested in and check current entries
  • add in any entry for any water you want to sell or buy

What information should I include in my ad?

  • If you are wanting to buy or sell
  • your name
  • phone number
  • name of river, creek, groundwater management area or irrigation district
  • how much water is to be traded
  • If the trade is temporary or permanent
  • term of the trade (Maximum term is 5 years)

Things you need to know
We are always looking for ways to improve our customer service. If you would like to provide feedack or suggested improvements please click here.

it's important to note that Southern Rural Water is not acting, and will not act, as a water broker.

We cannot advise you on price of water or match you individually with a buyer/seller.

Buyers and sellers still need to go through our normal application process.

Trading applications must be submitted to Southern Rural Water and approval granted before water is taken. A water transfer application form can be downloaded from our application page.

If you want to trade upstream, please speak with one of our Assessment Officers prior to submitting an application.

To check if a buyer or seller can trade with you, call us on 1300 139 510 and ask to speak to an Assessment Officer.

Not a water broker

It's important to note that Southern Rural Water is not acting, and will not act, as a water broker.

We cannot advise you on price of water or match you individually with a buyer/seller.

Buyers and sellers still need to go through our normal application process.

Click here to download our Fact Sheet