Lower Vasse River Management - Improving Water Quality

28 November 2024

The City of Busselton is continuing with its commitment to improving the health of the Lower Vasse River through the assessment of a new aeration trial.

The City’s Waterways Management Committee was established in 2024 and its members have been reviewing the outcomes of previous dredging work and other approaches to reduce algal blooms that occur each summer in the river, which are caused by excess nutrients from the urban and rural catchment.

Whilst the long term solution to prevent these nutrients from entering the local waterways, a range of approaches have been undertaken by the City and its partner agencies to look at ways to reduce algal blooms in the interim.

The State Government is the owner of the river, but in recent years the City has agreed to take on the role of Interim Asset Manager to enable a more responsive approach to ensuring its health. Investigating an aeration trial is the next step in our ongoing work to care for the river on behalf of the community.

Stage 3 of the City’s sediment removal program is currently in the procurement phase and still requires environmental approvals. The assessment of the aeration trial will be progressed through the Vasse Taskforce Water Quality Decision Support Framework and will require endorsement through the Vasse Ministerial Taskforce.

30 September 2024

Native fringing (riparian) vegetation of the Lower Vasse River has been largely cleared, leaving a narrow strip of remnant trees. The City of Busselton is working towards re-establishing this vegetation, and earlier this year a group of dedicate staff banded together and plant over 260 native seedlings along a section of the Lower Vasse River bank. After some well overdue rain in the past months, it’s great to see these plants thriving.

 Vegetation along the river provides important habitat for terrestrial fauna, with overhanging trees offering many roosting and nesting sites for waterbirds. In addition to providing habitat benefits, fringing vegetation is a vital component of river health. The important functions include: - supporting terrestrial and aquatic food webs; - habitat for terrestrial and aquatic fauna; - foreshore stabilisation; - maintaining cooler temperatures - interception of nutrients and sediments in runoff; and - nutrient uptake and processing.

The planting day was coordinated by the City’s Green Taskforce, a group of staff who collectively work towards raising staff awareness and encourage more sustainable behaviours in the workplace by running and supporting sustainability activities and initiatives.

11 June 2024

A group of City staff volunteered to spend some time planting 260 plants along the banks of the Vasse River last week. The plants were a mixture of locally native species common in areas along riverbanks, this included specifies suited for right on the water’s edge, to those that grow further out.

The plants will help provide important foraging and breeding habitat for native animals, increase connectivity of habitat by providing corridors for animals and areas that foster improved biodiversity and ecological function. In addition, the plants will improve bank stabilisation and reduce nutrients entering the river, provide shade to improve riverbank conditions and water quality, and improve resilience to climate change.  

Planting in riverside areas along the Lower Vasse River also aligns with strategies and actions in the Lower Vasse River Waterway Management Plan developed by the Department of Water and Environmental Regulation, City of Busselton and the Vasse Taskforce.

1 May 2024

The City of Busselton has completed a trial pit of approximately 4 tonnes of sediment testing on a section of the lower Vasse River. The purpose of the trial was to see how the material behaves when excavated/handled and will also undergo various tests including ASS (Acid Sulphate Soils) and water content. As this was a trial, there were no requirements to get any specific additional approvals. The material will be transported to the City’s transfer facility and will be further inspected and treated for ASS.

April 2024

The City of Busselton continues to work through its 6 staged-approach of sediment removal, established in 2022, with locations for each stage chosen based on water quality and priority.

The completion of the Stage 2 sediment removal in June 2023 saw approximately 670t of dry sediment removed. This sediment was laid to semi-dry in collection bags before being laid out on an Acid Sulphate Soils (AA) treatment pad at the Busselton Waste Transfer Station to treat and neutralise it. The City was then able to repurpose the sediment as daily cover at the Dunsborough Waste Facility.

The Department of Water and Environment Regulation (DWER) continue to monitor the water in the river to ensure effectiveness of the current sediment removal program. It was found during Stages 1 and 2 that pH levels and the clarity of the water were kept within acceptable ranges throughout the works. This data assists City and DWER officers with ongoing evaluation of the program.

In April 2024 the City advertised a tender for Stage 3 of the sediment removal process and this tender will close on 8 May. Stage 3 will focus  on the part of the river near Strelly Street to upstream of the river bend (see map). The total budget for Stage 3 is $938,025, with $407,964 funded by the State NRM Community Stewardship Program.

In addition to sediment removal works, DWER have conducted a large-scale application of a phosphorus-binding clay (Phoslock) from the Causeway bridge downstream to the pedestrian bridge. The results from this, plus the results from Stage 2 of sediment removal, will be presented to Council by DWER in June 2024.

The City of Busselton has also collaborated with DWER to develop a Water Treatment Assessment Framework ensuring decision-making on the management of the waterways (Lower Vasse River and Toby Inlet) is scientifically robust and evidence-based.

Work continues on waterway management and further updates will be provided when available.