Boundary Creek and Big Swamp remediation

Barwon Water is committed to developing and implementing a remediation plan to improve environmental outcomes for Boundary Creek and Big Swamp, so that confirmed impacts resulting from the historical management of groundwater extraction from the Barwon Downs Borefield is addressed.

Technical work in 2017 confirmed that intermittent use of the Barwon Downs Borefield over the past 30 years– combined with the effects of a dry climate –led to a reduction in flows to Boundary Creek and the subsequent activation of acid sulfate soils in Big Swamp (the Yeodene peat swamp).

In late February 2020, Southern Rural Water (SRW) accepted our proposed remediation and environmental protection plan for Boundary Creek, Big Swamp and the surrounding environment following 18 months of scientific studies, advice from independent technical experts and valuable community input through a community and stakeholder working group. This process was supported by the Victorian Government and legally enforceable through Section 78 of the Water Act 1989.

Remediation and Environmental Protection Plan implementation

Following acceptance by Southern Rural Water of the remediation and environmental protection plan for Boundary Creek, Big Swamp and the surrounding environment, we are excited to implement the adaptive management approach outlined in the plan.

Overview of the remediation plan

The Boundary Creek, Big Swamp and Surrounding Environment – Remediation and Environmental Protection Plan will be delivered under two parallel work packages:

  1. The Boundary Creek and Big Swamp Remediation Plan to address remediation of confirmed impact in the Boundary Creek catchment resulting from historical management of groundwater extraction from the Barwon Downs Borefield.
  2. The Surrounding Environment Investigation to investigate whether other areas within the regional groundwater system have been impacted by historical management of groundwater extraction from the Barwon Downs Borefield.

Boundary Creek and Big Swamp Remediation Plan

Boundary Creek is a tributary of the Barwon River. Approximately 19 kilometres long, it flows east through Barongarook, and joins the Barwon River at Yeodene, approximately 16 kilometres south-east of Colac. Big Swamp (also known as Yeodene Swamp) is a peat swamp on Boundary Creek. The swamp is located about 4 kilometres upstream from the confluence of Boundary Creek and the Barwon River.

The remediation plan for Boundary Creek and Big Swamp was developed to achieve an improvement to the environment so that:

  • Big Swamp and Boundary Creek have healthy and sustained ecological systems,
  • The impacts to the Barwon River are minimised and monitored, and
  • Fire risks / threats in Big Swamp are mitigated.

Based on a wide range of technical assessments and investigations, experts from various specialist fields and input from the community and stakeholder working group, the plan put forward the following remediation actions to be implemented.

  • Continued delivery of a supplementary flow so that Boundary Creek is flowing all year round.
  • Construction of barriers within the swamp to effectively distribute flow.
  • Infilling of the existing fire trenches and the drain to allow the swamp to retain more water over the winter months.
  • Prevention of the spread of some dry vegetation types so that wet vegetation species can recolonise.
  • Collection of ongoing monitoring data to inform any changes needed so that the remediation plan can adapt to how the environment is responding.
  • Feasibility of contingency measures.

Environmental improvements within the Boundary Creek catchment should be realised within the next decade.

Surrounding Environment Investigation

The Surrounding Environment Investigation considered an aerial extent of 480km2 - the whole extent of the regional groundwater system - as the basis of identifying other areas that may have been impacted by historical management of groundwater extraction from Barwon Downs.

Using a systematic risk based approach, the following areas were prioritised as potential ‘high’ risk requiring further investigation.

  • Barwon River (east branch)
  • Barwon River (west branch)
  • Barwon River (downstream of the confluence with Boundary Creek)
  • Gellibrand River
  • Ten Mile Creek (tributary of Loves Creek)
  • Yahoo Creek (tributary of Loves Creek)
  • Groundwater dependent ecosystems to the west (near Yeodene), including Barongarook Creek
  • Groundwater dependent ecosystems to the east (near Barwon Downs – Deans Marsh)
  • Groundwater dependent ecosystems to the south (along the Gellibrand River).

Additional monitoring and technical assessments will be carried out for these areas to confirm if there was impact caused by historic groundwater extraction. Monitoring assets to be installed are:

  • 22 groundwater monitoring bores,
  • Five surface water stream gauges, and
  • Six vegetation monitoring sites.

Outcomes for the Surrounding Environment Investigation will be progressively known with all eight areas to be complete by July 2023 to determine if further remediation action is required.

Community and stakeholder engagement

In May 2018, Barwon Water established a community and stakeholder working group to actively engage in the design of a remediation plan for Boundary Creek and Big Swamp. The group included representatives from:

  • Corangamite Catchment Authority (CCMA)
  • Colac Otway Shire
  • Traditional Owners
  • Land and Water Resources Otway Catchment (LAWROC) land care group
  • Environment Victoria
  • Upper Barwon Landcare Group
  • Boundary Creek landowners
  • and other interested community members.

The remediation working group nominated their own independent technical experts to provide specialist advice and support. They were:

  • Dr Vanessa Wong, senior lecturer, School of Earth Atmosphere and Environment, Monash University
  • Professor Richard Bush, Global Innovation Chair, International Centre for Balanced Land Use Office, Monash Sustainable Development Institute, Monash University
  • Dr Darren Baldwin, independent consultant, visiting adjunct professor, School of Environmental Sciences, Charles Sturt University.

The remediation and environmental protection plan was supported by the group and their nominated experts as it recognises the need for immediate action to remediate confirmed impacts within the Boundary Creek catchment (the Boundary Creek and Big Swamp Remediation Plan) and the need to investigate if there have been further impacts in an expanded area (the Surrounding Environment Investigation).

Background – section 78 Ministerial Notice

In September 2018, Barwon Water received a directive from the Minister for Water, pursuant to Section 78 of the Water Act 1989. The notice directs Barwon Water to:

  • prepare and implement a remediation and environmental protection plan for Boundary Creek, Big Swamp and the surrounding area, and
  • discontinue any extraction activities (other than for maintenance and emergency response purposes) while the assessment is being completed and until all remediation work outlined in the remediation plan has been completed.

Barwon Water welcomed the notice for a legally enforceable remediation plan, noting that we had already been working proactively on activities consistent with these objectives.

Background – Scope of works

Prior to the development of the Remediation and Environmental Protection Plan, Barwon Water had submitted a scope of works in July 2019 in accordance with the section 78 notice. The scope of works incorporated feedback received from Southern Rural Water and the independent technical review panel.

The scope of works outlined the area covered by the remediation plan, the environmental values included and the necessary environmental assessments and methodology proposed to develop the remediation plan.

In developing the scope of works, we considered:

  • all appropriate hydrogeological, hydrological and geochemical assessments
  • community feedback via the Boundary Creek and Big Swamp remediation working group and nominated expert panel
  • feedback from Southern Rural Water’s independent technical review panel
  • the State Environmental Protection Policy (Victorian Waters)

Scope of Works: Section 78 Scope of works - revised (PDF 7.2 MB)

Gerangamete groundwater management area annual report

Barwon Water has been operating under Groundwater Extraction Licence No. BEE032496 that expired on 30 June, 2019. This report covers the annual reporting requirements under this licence.

On 14 March 2019, Barwon Water withdrew its licence renewal application for the Barwon Downs borefield until remediation of historical impacts of groundwater pumping is complete under the Section 78 Ministerial Notice.

This report presents a summary of the work completed for the monitoring of groundwater and land levels in the Gerangamete groundwater field for the period July 1, 2018, to June 30, 2019, and includes:

  • the extracted groundwater volume
  • groundwater and land level data recorded
  • an account of bore maintenance undertaken
  • an indication of any analysis completed based on the monitoring data.

The major outcomes of the 2018-2019 program were:

  • no groundwater was extracted
  • groundwater level decline and ground subsidence remain within licence trigger levels
  • groundwater levels recorded during 2018-2019 show a recovery trend.

Due to the expiration of the existing licence, the production of an annual report will no longer be required making this the concluding report for Groundwater licence No: BEE032496.

Learn more at our dedicated microsite

We’ve set up dedicated microsite for the Boundary Creek and Big Swamp remediation process.

The site includes a comprehensive document library, frequently asked questions, news archive and more.

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