Project overview
iEnvi completed environmental compliance audits and baseline condition investigations across four metropolitan bus depots in Melbourne, with a detailed program at a central depot. The work established a defensible environmental baseline to support ongoing depot operation, regulatory compliance and property/transaction due diligence.
Why this was required
Longstanding industrial use, on‑site refuelling and adjacent historic landfill use created potential pathways for soil, groundwater and vapour contamination. The Client needed:
- an evidence‑based statement of site condition for asset management and the Department of Transport and Planning (DTP) requirements;
- to confirm whether contamination met the test for notifiable contamination under Victorian law; and
- practical risk controls so operations could continue without increased exposure or regulatory risk.
Scope of work
- desktop review of site history and previous investigations;
- development of a site conceptual model and risk register;
- intrusive investigation: 18 soil samples collected at the central depot and groundwater sampled from two monitoring wells (site totals reported by project);
- landfill gas checks at perimeter and receptor locations adjacent to closed landfill areas;
- environmental compliance inspections and consolidated Environmental Site Assessment reporting.
Key technical findings
- Localised hydrocarbon impacts were identified in soils in the vicinity of refuelling infrastructure. These impacts were generally contained beneath sealed hardstand areas and, on the basis of the investigation data and current site use, did not present an unacceptable exposure pathway to depot workers or nearby receptors.
- Groundwater monitoring from the two onsite wells showed no evidence of an active, migrating groundwater plume; concentrations were consistent with improving conditions over time (site data). Continued periodic groundwater monitoring was recommended to confirm stability.
- Landfill gas checks found no landfill‑gas migration risk from adjacent closed landfills to the depots at the time of investigation.
- Across the wider project iEnvi identified gaps in historical investigations (sampling density, missing groundwater data and limited vapour screening) and provided targeted follow‑up investigations to close those gaps.
Regulatory and technical context (summary)
Assessment and reporting followed nationally accepted site contamination practice and sampling guidance to ensure defensible results for regulatory, planning and transaction purposes. Industry guidance (NEPM schedules and recognised sampling standards) informs appropriate soil, groundwater and vapour sampling, while Victoria’s Environment Protection Act 2017 establishes a duty to notify EPA for prescribed notifiable contamination and to manage contaminated land so far as reasonably practicable.
Outcomes and benefits to the client
- Clear, consolidated baseline of environmental conditions suitable for due diligence, asset management and DTP reporting needs.
- Practical, prioritised risk controls including a recommended Fuel System Operating Plan (FSOP), routine inspection checklists for refuelling areas and an agreed groundwater monitoring regime to provide early warning of change.
- Consolidated Environmental Site Assessment reports that closed identified gaps and reduced the risk of regulatory escalation; the investigations did not, on the information provided, trigger a notifiable contamination notification under Victorian requirements.
- Reduced transaction and operational risk: the Client can continue depot operations with documented controls and a monitoring program that supports ongoing compliance and asset valuation.
Practical takeaways for operators and asset owners
- Maintain sealed hardstand and good drainage around refuelling bays; these simple controls reduce exposure and reduce the likelihood of contamination migration.
- Adopt a Fuel System Operating Plan (FSOP) and train operators — it reduces spill frequency, clarifies response steps and supports regulatory compliance.
- Keep groundwater monitoring records and trend data — regulators and buyers expect to see an ongoing monitoring program where groundwater could be affected.
- Where landfills are in the vicinity, periodic landfill gas checks and an understanding of local buffer/landfill management plans are a prudent part of risk management.
Next steps
If you operate or manage depot assets, iEnvi can rapidly assess liabilities, prepare an appropriate FSOP, implement monitoring and produce consolidated reports suitable for regulators, transport authorities and transactions.