Remediation Action Plans for Contaminated Land

Confluence Environmental prepares Remediation Action Plans (RAPs) for contaminated land projects across NSW, providing the technical framework for remediation, validation and subsequent development.

A RAP is generally prepared where site investigation has established that contamination requires remediation, containment or ongoing management before land can be considered suitable for its existing or proposed use.

The plan defines the remediation objectives, preferred remediation strategy, implementation requirements, environmental controls and validation process. Depending on the site, this may involve contaminated soil removal, on-site treatment, containment, asbestos in soil remediation, groundwater management or longer-term management of residual contamination.

Where a Preliminary Site Investigation or Detailed Site Investigation has already been completed, Confluence can review the available information and determine whether the site has been sufficiently characterised to proceed to remediation planning.

What Is a Remediation Action Plan?

A Remediation Action Plan, also commonly referred to as a Remedial Action Plan, translates the findings of contaminated land investigation into a practical strategy for managing identified contamination.

The RAP builds on the site's Conceptual Site Model, investigation findings and proposed land use to determine what contamination requires remediation, what outcome must be achieved and how that outcome will be demonstrated.

A well-developed RAP should answer several key questions:

• What contamination requires remediation or management?

• What are the remediation objectives?

• What remediation options are available?

• Which strategy is most appropriate for the site?

• How will contaminated soil and other affected media be managed?

• What controls are required during the works?

• How will successful remediation be validated?

• Will any residual contamination remain and require ongoing management?

The purpose is not simply to specify that contaminated material should be excavated. The RAP should provide a clear and implementable remediation strategy aligned with the proposed development.

When Is a Remediation Action Plan Required?

A RAP is generally prepared once contamination has been sufficiently characterised and remediation or management is required.

This may occur where:

• a Detailed Site Investigation identifies contamination requiring remediation;

• contaminated soil requires excavation, treatment, containment or management;

• contamination needs to be addressed before redevelopment or a more sensitive land use;

• asbestos in soil requires a defined remediation strategy;

• former fuel infrastructure or hydrocarbon impacts require remediation;

• residual contamination will remain beneath a completed development;

• remediation is required through a planning or regulatory process; or

• the project is subject to independent review under the NSW EPA Site Auditor Scheme.

An exceedance of an investigation or screening criterion does not automatically mean remediation is required. The need for remediation should be determined from the overall site assessment, the Conceptual Site Model, relevant exposure pathways and the proposed land use.

Where the available investigation has not adequately defined the nature or extent of contamination, additional investigation or delineation may be required before a RAP can be finalised.

Remediation Strategy Development

The remediation strategy is developed from the contamination conditions, remediation objectives and practical requirements of the project.

Depending on the site, contaminated land and soil remediation options may include:

• excavation and off-site disposal of contaminated soil;

• targeted removal of contamination hotspots;

• segregation and controlled management of impacted materials;

• on-site treatment and reuse where appropriate;

• capping or containment of residual contamination;

• in-situ or ex-situ treatment;

• asbestos in soil remediation;

• removal of underground petroleum storage systems and associated impacts;

• groundwater remediation or management; and

• long-term management of residual contamination.

The preferred approach is selected with consideration of risk reduction, technical effectiveness, constructability, soil and waste volumes, environmental impacts, development requirements, project timing and site constraints.

A RAP should not automatically assume that all contaminated soil needs to be removed. On many projects, targeted excavation, treatment, containment or controlled management can achieve the required remediation outcome while reducing unnecessary soil movement and disposal.

Remediation Planning and Implementation

Once the preferred remediation strategy has been established, the RAP defines how the works are to be implemented and controlled.

Depending on the scale and complexity of the project, this may include:

• remediation areas and objectives;

• remediation and validation criteria;

• excavation, treatment and containment requirements;

• soil segregation and stockpile management;

• contaminated soil disposal and waste classification requirements;

• imported material requirements;

• asbestos in soil controls;

• groundwater and surface-water management;

• dust, odour, noise and erosion controls;

• unexpected finds procedures;

• environmental monitoring;

• contingency measures;

• validation sampling and hold points; and

• reporting and record-keeping requirements.

The level of detail is developed around the proposed remediation works rather than applying a standard methodology to every site.

For larger or more complex projects, the RAP can also define how remediation interfaces with contractors, demolition, civil works, earthworks and staged construction.

Contaminated Soil and Waste Management

Contaminated soil is one of the most common drivers for site remediation, but the appropriate management pathway depends on the nature and extent of contamination and the proposed use of the land.

Where practicable, the remediation strategy may distinguish between:

• material requiring removal;

• soil suitable for treatment;

• material suitable for controlled reuse;

• soil that can remain in place without creating an unacceptable exposure pathway; and

• material requiring off-site disposal.

This distinction can be particularly important on larger developments where unnecessary excavation and disposal can substantially increase earthworks and waste costs.

Where contaminated soil is removed from site, waste classification and disposal requirements may also need to be incorporated into the remediation program. Contaminated-land assessment criteria and waste classification criteria serve different purposes, so soil requiring remediation cannot automatically be assigned a waste classification from DSI results alone.

Confluence can coordinate contaminated land assessment, waste classification, material tracking and remediation planning as part of the broader project.

Remediation Designed Around Development and Construction

Effective contaminated land remediation should be developed with the proposed construction works in mind.

Confluence considers demolition sequencing, bulk earthworks, excavation levels, proposed buildings and infrastructure, soil movement, construction access, disposal requirements and project programming when preparing the RAP.

This can help integrate remediation into the broader construction program and reduce unnecessary material handling, duplicated excavation or disruption during delivery.

For staged developments, operational facilities and constrained sites, remediation can also be planned around progressive access to different areas of the site.

The objective is to develop a remediation strategy that is technically defensible while still being practical to construct and implement.

Validation Planned from the Beginning

A RAP should establish how successful remediation will be demonstrated before remediation works commence.

Validation requirements are therefore developed alongside the remediation strategy so that appropriate inspection, sampling and documentation can occur as the works progress.

Depending on the remediation approach, validation may include assessment of:

• excavation bases and walls;

• residual soils;

• treated soils;

• imported materials;

• containment systems;

• groundwater;

• asbestos-affected areas; and

• other environmental media relevant to the Conceptual Site Model.

Where contamination is deliberately retained or managed in place, the RAP may also establish requirements for an Environmental Management Plan, long-term monitoring or other ongoing management measures.

The objective is to provide a clear and defensible basis for demonstrating that the remediation objectives have been achieved and that the site is suitable for its intended use.

Integrated Contaminated Land Capability

Confluence can support projects through the complete contaminated land assessment and remediation process:

Preliminary Site Investigation → Detailed Site Investigation → Remediation Action Plan → remediation support → validation

Maintaining continuity through the investigation, remediation and validation stages helps keep the Conceptual Site Model, remediation objectives and validation strategy aligned as the project progresses.

Where required, our contaminated land team can also coordinate related services including asbestos in soil assessment, groundwater monitoring, waste classification and environmental management.

Technical and Site Auditor Review

Confluence prepares RAPs for projects ranging from localised soil contamination through to complex remediation programs involving multiple contaminants, Areas of Environmental Concern and environmental media.

Our experience includes sites affected by historical filling, fuel infrastructure, asbestos in soil, metals, hydrocarbons and other industrial or commercial contamination.

We also prepare Remediation Action Plans and supporting contaminated land documentation for independent technical review and review under the NSW EPA Site Auditor Scheme.

Reports are subject to technical quality assurance appropriate to the complexity of the project, with CEnvP Site Contamination (CEnvP-SC) and CPSS CSAM review or endorsement available where required.

Remediation Action Plans Across NSW

Confluence Environmental prepares Remediation Action Plans and contaminated land remediation strategies across NSW, including Newcastle and the Hunter, Lake Macquarie, Maitland, the Central Coast, Sydney and Greater Sydney, the Mid Coast, Mid North Coast and regional NSW.