The headwater tributaries of our waterways are often of the highest quality, surrounded by native vegetation and providing high quality water and habitats.
One of the few threats to the ongoing function of these systems is invasion by introduced weed species such as Willows. The WGCMA headwater willow control program aims to stop willows from establishing large populations in these environments. .
Local farmers and community groups have worked with us on many downstream sections of rivers and creeks to undertake river restoration projects.
This work often involves willow control, , fencing and revegetation with native plants to protect their sections of the waterway. The headwater willow control program helps save thousands of dollars and many hours of work by eradicating willows upstream, stopping them from becoming a downstream problem.
Need
Most species of willows are weeds of national significance. They are among the worst weeds in Australia because of their invasiveness, potential for spread and economic and environmental impacts.
They have invaded riverbanks and wetlands in temperate Australia, occupying thousands of kilometres of streams and numerous wetlands areas.
Willows reduce water quality, flow and input a large amount of organic matter into waterways when they drop their leaves in autumn.
Willows spread rapidly and will infest the middle of our waterways, eventually creating thickets which choke the middle of the waterway which divert high flows into adjacent riverbanks leading to erosion issues and stream diversions.
Willows use more water than native vegetation. For natural resource management bodies across Australia, the goal is to remove willows from waterways and replace them with native vegetation.
This program supports our work with farmers downstream, by stopping upstream willows becoming a downstream problem.
Planning
Targeted waterways for this program were selected based on the priorities in the West Gippsland Waterway Strategy and the knowledge of our staff and partners.
The aim is to eradicate willows and other target weeds in these waterways’ remote headwaters and effectively ‘cleanse’ the waterway of these invasive species from its source down to the public/private land interface, where forest gives way to cleared agricultural land in many cases.
Targeted waterways include the following rivers and high value tributaries in the Strzelecki Ranges and Southern Alps;
- Thomson River
- Macalister River
- Avon River
- Latrobe River
- Agnes River
- Franklin River
- Albert River
- Jack River
Controlling willows in these priority areas is cost-effective as it helps maintain their good-excellent condition and reduces the downstream spread of willows, thereby reducing ongoing maintenance costs and improving safety and access for recreational users enjoying water activities such as fishing, kayaking and rafting.
Works
Focussed on rivers as they make their way down to the flatter areas of Gippsland, the headwaters program works on rivers in the more mountainous, less accessible country.
Works included contractors walking the length of the rivers, treating the willows with herbicide, then marking the points on GPS to allow them to come back in future years for targeted follow up. A total of 175.4km of waterway was inspected and treated this year with sites accessed on foot or from a raft by specialist contractors.
Where willows were detected, their location was recorded (by handheld GPS to help inform management) and they were poisoned with herbicide. Of the 175.4 km inspected in 2020, 52% (92 kms) of the area re-treated was focused on tributaries of the Avon River Catchment. This included stretches along Ben Cruachan Creek and the Valencia Creek.
During this project thus far, inspection and treatment of willows has been completed
- along 387 km of waterway
- covering 1,280 ha riparian land
Follow up treatment of willows has occurred along an additional 225.4 km of waterway, covering 1,205 ha of riparian land in the headwater areas of the Thomson, Macalister and Avon Rivers.
Planning and delivery of the remote willow control program was undertaken in accordance with the WGCMA’s Headwater Willow Control Operation Plan 2016-2020, and in collaboration with public land managers Parks Victoria and DELWP. WGCMA’s remote willow control complements the weed control undertaken by these public land managers.
Outcomes
The incredible gains made by this work will benefit the protection of these high value habitats in the headwaters of the Gippsland Lakes and Corner Inlet catchments.
Continued follow up treatment will not only support these reaches becoming ‘willow free’ in future but also have the added benefit of preventing willow spread further downstream. This will enhance the legacy of downstream riparian works and available habitat in the catchments.
The focus in the 2019/20 year has been to revisit sites previously treated in this project to assess if any further treatment was required.
The ability to do this over a four-year project ensures a high-quality legacy of the works delivered. It is also more cost effective to address new re-emerging weeds early.
Planning and delivery of the remote willow control program was undertaken in accordance with our operation plan, and in collaboration with public land managers Parks Victoria and DELWP. This remote willow control complements the weed control undertaken by these public land managers.
Page updated November 25th 2020