East Barwon Willow Removal project update

Barwon Water’s works on the East Barwon willow removal project to improve water transfer capacity and river health are progressing well.

On December 2 last year, Forrest-based civil earthmoving contractors Deja Eight began preparing the site to start removing the invasive willow trees that choke a stretch of the East Barwon River, restricting flow and causing increased flooding, upstream of the Wurdee Boluc channel.

Following a Cultural Heritage Induction based on the Cultural Heritage Management Plan, which Eastern Maar Traditional Owners Corporation approved in November, the site preparation work, including chemical treatment of the willow trees through stem injection, was completed prior to the Christmas break.

Work to remove the willows began on January 4 starting on the southwest side of the river and the willow waste is being stockpiled on site.

Barwon Water has been working closely with Deja Eight, sub-contractors Organic Matter Solutions and DELWP in preparation to safely manage the processing of the willow waste on the river flats in self-contained air burner units.

A planned burn risk assessment, facilitated by Forest Fire Management Victoria (FFMVic) team has been developed and will be included as a planned burn within the 2021/22 Joint Fire Management Program.

Starting in early February, it is expected to take one week to process the willow waste, operating the air burner units over a 24-hour cycle.

Further details on the air burner operation will be provided to the community via FFMVic planned burn notifications.

Meanwhile, a contract for the tailored riparian revegetation program was awarded to local contractor Tree Management Services.

Propagation of seedlings has started in preparation for planting next spring.

The establishment of riparian vegetation is a key aspect of the project and will help stabilise the reach, reduce stream velocities and siltation, and provide a buffer to reduce pathogens and nutrients entering the waterway.

Establishment of a dense over-storey is also important in shading the river, limiting the spread of Glyceria, and providing continuous habitat for fish and other aquatic fauna.

Three research projects associated with the works are also being undertaken by Deakin University researchers focusing on riparian buffers within the Upper Barwon catchment. They include:

• a PhD project focusing on the effects of willow removal and the physical characteristics of riparian restoration on water quality, microclimate, and morphology (this project is being sponsored by Barwon Water, Deakin and Water Research Australia)
• a masters project to develop a tool for calculating the costs and benefits of riparian buffers for stakeholders, and
• an honours project investigating leaf decomposition rates and processes between streams.

Completion of the willow removal works are expected by April 30.

Barwon Water has also been appointed Committee of Management for this 3.5 kilometre section of the East Barwon River and will be responsible for the long term management of the riparian vegetation through this reach.

Background

Barwon Water is co-ordinating a project to rehabilitate a 3-kilometre section of the East Barwon River. Barwon Water uses this section of the river to transfer water from its West Barwon Reservoir to the Wurdee Boluc Reservoir.

Willow infestation has caused loss of transfer capacity through this section of the East Barwon River, which reduces Barwon Water’s capacity to transfer water and leads to flooding of adjacent properties.

Barwon Water worked with Eastern Maar Traditional Owners Aboriginal Corporation on a Cultural Heritage Management Plan for the project, and is collaborating with local landowners.

Barwon Water has a strong commitment to environmental improvement and is also supporting the Corangamite CMA and landowners on improvements to the health of the East and West Barwon Rivers in other areas.