The Boundary Creek and Big Swamp areas are recovering, both above and below the surface, as Barwon Water’s key remediation activities have a positive effect on the local environment.

Decommissioning of the former borefield extraction bores, release of supplementary flows to Boundary Creek and ongoing environmental monitoring were among the initiatives undertaken in the past financial year.

The details are contained in the Remediation and Environmental Protection Plan (REPP) Annual Report 2024-25, which has been publicly released.

Barwon Water’s efforts to address the impacts caused by groundwater pumping activities at the Barwon Downs borefield have been guided by the REPP, since its creation in 2020.

The Annual Report notes that all remedial actions have been completed or are progressing under the REPP.

Despite persistent dry conditions, groundwater levels in the Lower Tertiary Aquifer continued to recover, with water in bores adjacent to Boundary Creek nearing or exceeding their targets.

Supported by the ongoing release of supplementary flows (about 233 ML) into the upper reaches of Boundary Creek, positive results were also recorded in Big Swamp.

Thirteen of the 15 bores within Big Swamp’s Upper Aquifer system have consistently met or exceeded their water level targets.

The ongoing recovery is providing suitable conditions for the reestablishment of wetland species and habitat, with dense, healthy vegetation now spread across the majority of the swamp.

General Manager Planning, Delivery and Environment Seamus Butcher thanked the project’s Remediation Working Group, and the wider local community, for its ongoing interest and input into the longer-term process.

“The remediation works continue to positively progress, with a number of targets met and other initiatives advancing well,” Mr Butcher said.

The REPP Annual Report details recent highlights, including the decommissioning of the former Barwon Downs borefield extraction bores.

The works, which were overseen by an independent hydrogeologist and Southern Rural Water’s drilling inspector, began in late 2024 and were completed in March 2025.

A borefield decommissioning field day, which included a public tour and viewing of the works, was among a range of community and stakeholder activities offered throughout the year.

Two electro-fishing and water bug identification events with primary schools were also held, in collaboration with Corangamite Catchment Management Authority and Arthur Rylah Institute.

The Barwon Downs borefield was in the foothills of the Otway Ranges, about 30 kilometres south-east of Colac.

Barwon Water acknowledged in 2017 that the use of the borefield had led to a reduction in groundwater flows into select reaches of Boundary Creek, a tributary of the Barwon River.

A Remediation and Environmental Protection Plan (REPP) was then created to improve water flows, water quality, vegetation and ecology in Boundary Creek and Big Swamp.

The full REPP Annual Report 2024-2025 is available at https://www.yoursay.barwonwater.vic.gov.au/boundary-creek.