Detailed Site Investigations

Detailed Site Investigation and Site Characterisation

Confluence Environmental undertakes Detailed Site Investigations (DSIs) to characterise actual or potential contamination and provide a clear technical basis for planning, development, remediation and property decisions.

A DSI is generally undertaken where a Preliminary Site Investigation, previous assessment or other site information identifies contamination or a material data gap requiring further investigation.

The assessment defines the nature, extent and significance of contamination, considers potential risks to human health and the environment, and establishes whether the site is suitable for its existing or proposed use.

Depending on the findings, the investigation may demonstrate that no further assessment is required, identify specific areas requiring further characterisation or management, or provide the information necessary to develop a Remediation Action Plan.

Site Investigation Capabilities

The investigation scope is developed from the site history, Conceptual Site Model, identified Areas of Environmental Concern and proposed land use.

Depending on the project, our investigations can include:

• soil investigation using test pits, boreholes, augering and drilling;

• groundwater investigation including monitoring well installation and sampling;

• soil vapour and ground gas assessment where volatile contaminants or gases may present a potential pathway;

• surface water and sediment investigation where contamination may affect receiving environments; and

• asbestos in soil assessment where asbestos-containing material is known or suspected within fill or surface soils.

The environmental media investigated are selected to address the identified contamination risks rather than applying a standard investigation program to every site.

Investigation Design

Effective site characterisation begins with understanding the decision the investigation is required to support.

We review the available PSI, previous environmental data, proposed development and relevant planning or Site Auditor requirements before refining the Conceptual Site Model and identifying the remaining data gaps.

Sampling programs are then developed to provide representative, fit-for-purpose information using systematic, targeted, judgemental or stratified approaches as appropriate.

Where reliable existing investigation data are available, these are considered as part of the assessment rather than unnecessarily repeating previous work.

Clear, Defensible Outcomes

A Detailed Site Investigation should provide more than laboratory results.

Our reports define the contamination conditions identified at the site, assess their significance in the context of the proposed land use and provide a clear pathway forward.

Recommendations may include:

• no further contaminated land assessment;

• targeted investigation of remaining data gaps;

• management of localised contamination;

• remediation; or

• preparation of a Remediation Action Plan.

The objective is to provide the information required to support a clear and defensible project decision.

Integrated with Planning and Development

Contaminated land investigations are designed with consideration of the broader project.

We consider matters such as proposed land use, excavation, existing buildings, demolition sequencing, operational constraints, soil management and construction programming when developing the investigation strategy.

This allows contamination risks to be addressed at the appropriate stage of the project while maintaining the technical confidence required for planning, regulatory or Site Auditor review.

Experience Across Complex Contaminated Land Investigations

Confluence Environmental has experience undertaking Detailed Site Investigations across industrial, commercial, development and major infrastructure environments.

Our work includes investigations involving historical filling, former fuel infrastructure, wastewater systems and multiple Areas of Environmental Concern, with assessment extending across soil, groundwater, surface water and soil vapour where required.

We also have experience delivering investigation programs within independent technical review and Site Auditor frameworks.

Detailed Site Investigations Across NSW

Confluence Environmental undertakes Detailed Site Investigations across Newcastle and the Hunter, Lake Macquarie, Maitland, the Central Coast, Sydney and Greater Sydney, the Mid Coast, Mid North Coast and regional NSW.