Contact Us


Wimmera CMA

Street Address:
24 Darlot Street, Horsham, 3400
(enter via Gleed St)

Postal Address:
PO Box 479, Horsham, VIC, 3402
Phone: (03) 5382 1544
Fax: (03) 5382 6076
Office Hours:
Monday to Friday, 8:30 - 5:00pm
(excluding Public Holidays and Christmas - New Year Closure.  Office may also be closed for short periods Monday mornings)

Environmental Water Releases

What are environmental water releases?

Environmental water releases are designed to supply sufficient volumes based on scientific recommendations to improve conditions for aquatic, wetland, and riparian ecosystems. In the Wimmera’s regulated rivers and creeks these are typically base flows and freshening flows, which assist in improving water quality and habitat for aquatic species as well as increasing the abundance and diversity of riparian and aquatic vegetation. Sometimes flows are deliberately stopped for a number of days in summer/autumn, which is called a ‘cease to flow,’ reflecting the typical conditions during those drier months.

 Dimboola WeirDimboola Weir

Environmental water releases occur as either volumes released from storage, that are deducted from the Bulk Entitlement allocation held by the Victorian Environmental Water Holder (VEWH), or as passing flows, where a proportion of stream flows, that makes their way to weirs or water storages, is allowed to continue. Passing flows do not apply to environmental water releases for wetlands.

Some parts of the flow regime for rivers and creeks (such as high and overbank flows) cannot be delivered via weirs and storages due to outlet capacities and flooding risks. However, these overbank and high flows happen in much of the region when conditions are wet enough such as during the spring/summer of 2010-2011. In some instances of wetlands that are supplied by the Wimmera-Mallee Pipeline, limited pipe capacities means that localised run off, under wet conditions, is required to fill them and releases can only inundate a small proportion of the wetland.

Creeks, rivers, and wetlands that are watered and the volumes they receive, vary on an annual basis and are dependent on a number of factors such as: the allocations available, catchment conditions, what water has been provided in previous years, and the watering needs of the environmental values of these waterways. These are all considered during the planning process for environmental watering which in turn is submitted as a Seasonal Watering Proposal to the VEWH for their consideration and inclusion in their Seasonal Watering Plan for Victorian rivers, wetlands, and floodplains. The VEWH then authorises the Wimmera CMA to implement certain elements of the Seasonal Watering Plan depending on allocations. Wimmera CMA implements the authorised components with water storage managers GWMWater, who release the water on the CMA’s behalf. The storage manager has discretion over these releases if they affect other objectives like efficiency of storage operations.

Seasonal Watering Plans

Wimmera CMA's and Western Region (including the Wimmera) proposed seasonal watering plans.

Environmental Flows Updates

Environmental Water Flow updates are released each season to report what water flows are occurring and scheduled for that season and to share information on how these flows are helping our environment.

Wimmera Water for the Environment: Autumn Update

Apr 12, 2019

Autumn EWR UpdateWater for the Environment


The Wimmera couldn’t be a more perfect backdrop for global movie star Eric Bana and his entourage for filming of the internationally-bestselling Australian novel ‘The Dry’ right now.

The parched landscape Jane Harper transports us to in her novel creates drama and tension essential to the plot, and bringing her story to life here during our dry autumn is a stark reminder that the Wimmera environment is under pressure.

Since 2016 our region has experienced hotter and much drier than average weather conditions. The Wimmera River at Glenorchy hasn’t had natural flows for about 18 months. It’s drier than it was in the depths of the Millennium Drought in 2006, and is experiencing the longest period of no flows through the flow measurement gauge since its installation in 1964.

We’re starting to see the impacts with poor water quality and a lack of habitat in many waterways. Our focus is on protecting drought refuges – deep pools often shaded by large red gums and other trees. This is so our fish, platypuses, turtles, crayfish and frogs can persist and recover when conditions improve.

How we make every drop count

Through improved management, science and infrastructure of water for the environment, we continually aim to put our region in a much better place to deal with droughts. 

  • We work with community groups and councils to manage weir pool water levels and the timing of short periods of higher flow, which are important for mixing and diluting salty water and helping fish move between deep pools.
  • We reduce environmental flows to reflect drought conditions to preserve allocations for water the environment in subsequent years to target particular areas if it remains dry.
  • We have identified pools along the Wimmera River with potential to be supplied from the Wimmera Mallee Pipeline if there are long periods since they have experienced any flow.
  • We work with fish, platypus and vegetation scientists and the community to identify and monitor key refuge pools and the minimum flows needed to sustain them.  

Want to get involved?

Join our community wetland monitoring program, post any platypus sightings on PlatypusSPOT or tag us on social media when you’re outdoors - even if you just want to share your love of the Wimmera environment, because we love it too! 


An environmental flow in a drying reach of the upper Mt William Creek between Lake Fyans and Lake Lonsdale is helping keep a valuable native fish population going until the sky delivers its next burst of natural flows.

“There’s a good population of fish in that Mokepilly area but because it’s not getting any inflows and is on the verge of going dry, we need the environmental water to hold breeding stock and enhance this fishery into the future. Rivers are where a lot of our fish breed and when it’s dry like this, and our lakes are in a bit of trouble, it’s important to keep our rivers healthy so they can keep producing good fish.” Lake Lonsdale Action Group member and Stawell Angling Club President Ray Howard

“In hard times fish numbers suffer, and from our most recent surveys this appears to be the case. When Wimmera CMA did the first environmental watering in 2015 and 2016 it helped the fish get through to the next breeding cycle, which maintained and boosted fish numbers. We hope we will see a similar result this time.” Environmental researcher Dion Iervasi, Austral Research and Consulting



Low flows and periods of no flow will continue for the MacKenzie River and Burnt Creek through to Wonwondah. Low flows are also taking place for the Wimmera River from Taylors Lake. We have delivered flows to refuge pools on the Mt William Creek to refill them and improve water quality.


Wimmera River System Environmental Watering Management Plan (EWMP)

The Environmental Water Management Plan for the Wimmera River System establishes environmental objectives for the Wimmera River and its regulated tributaries (lower Mt William Creek, MacKenzie River, Burnt Creek and Bungalally Creek) as well as the Yarriambiack Creek, the scientifically determined environmental water requirements to attain these objectives set out over a multi-year watering regime (assuming sufficient environmental water is available).
Environmental Watering Management Plan for Wimmera River System

Wimmera Mallee Pipeline Wetlands Environmental Water Management Plan

The Wimmera CMA co-ordinates the delivery of environmental water to thirteen wetlands across the Wimmera CMA region (there are 38 others in the North Central and Mallee CMA regions). The Environmental Water Management Plan for these wetlands set out the multi-year watering objectives for these wetlands assuming that sufficient environmental water is available for them.
Environmental Watering Management Plan for Wimmera Mallee Pipeline Wetlands

Environmental Water Release Alerts via SMS

Wimmera CMA offers a SMS alert service, which sends text messages concerning when and where environmental flows are occurring, what they aim to achieve, and flow rates.

To sign up, send a sms with the word ‘register’ and full name and locality to 0427 871 565 or email Wimmera CMA.

Text messages will provide information specifically about environmental flows released from storages. Natural flows along creeks and rivers will not be part of this service.

More information - Why we need environmental flows

These fact sheets by Victorian Environmental Water Holder help to further explain why we need environmental flows:

  1. What is environmental water?
  2. Why is environmental watering important?
  3. What does environmental watering aim to achieve?
  4. What does environmental watering involve?
  5. How do we know if environmental watering is successful?
  6. What is environmental water trading?

Find out more about environmental flows on this video: why we need environmental flows