Truck Rollover Delineation Assessment and Remedial Strategy

Challenge

SLR conducted a Delineation Assessment and assisted with providing a response to a notice issued by local council in relation to diesel contamination of land resulting from a truck rollover.

Following the delineation of hydrocarbon impacts, an assessment was completed to determine the technical feasibility and provide a design basis for execution of on-site remediation (i.e. excavation).

Site constraints and hazards included:

• The proximity of the site to:
  - A neighbouring agricultural property.
  - Electrical infrastructure; and
  - A highly trafficked road within a 70km/hr speed limit zone.
• Impacts of excavation activities to local residents, businesses and road users.
• Constraints of the road reserve (the available space for works was approximately 4 metres).

Solution

In response to the notice requirements, SLR were engaged to complete the following:

• Provision of a Delineation Assessment Report on the lateral and vertical delineation of the known hydrocarbon impact and provision of remedial strategy.
• A Remediation Feasibility Assessment & Work Plan consisting of the following:
  - Remediation and Management Feasibility Assessment to identify the extent of contamination that can be reached using unsupported (conventional) and supported (e.g. shoring, sheet piles and anchors) excavation methods.
  - Geological cross-sections showing the occurrence of soil contamination but also showing the distribution of lower concentrations of hydrocarbons.
  Assessment of residual risks by means of a Conceptual Site Model and Qualitative Risk Assessment.
  - Detailed scope for the ongoing management of hydrocarbon impacts.