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.
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.
Wimmera CMA’s and Western Region (including the Wimmera) proposed seasonal watering plans.
- VEWH Seasonal Watering Plan – Section 4 Western Region Accessible Version (includes the Wimmera) (DOC, 5.6MB)
- VEWH Seasonal Watering Plan – Section 4 Western Region (includes the Wimmera) (PDF, 16MB)
Find out more about environmental flows in this video:
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.
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
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.
Why we need environmental flows
These fact sheets by Victorian Environmental Water Holder help to further explain why we need environmental flows.
What is environmental water? PDF, 4 MB
What is environmental water trading? PDF, 968 KB