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Testers Hollow Remediation

Project Management / Planning

Client Information

Winten Property Group
6 months
Cliftleigh / Testers Hollow

Design Management

Remediation management

Acid Sulphate Soil Management Plan

Statutory & Service Authority Approvals


Monteath & Powys manage the identification, scoping, approvals, contract delivery, and verification of land remediation projects.

Winten Property Group engaged Monteath & Powys to manage the design and approvals necessary to complete the remediation and rehabilitation of Testers Hollow Wetlands at Cliftleigh. Part of the project required the conversion of an old fish farm into a stormwater detention basin of sufficient capacity to service the proposed 1000 lot residential subdivision adjacent to the wetlands.

To construct the detention basin a series of earth walls required removal to convert the segregated fish farms into a single water body. During the design process it was established through geotechnical investigations that significant quantities of Potential Acid Sulphate Soils (PASS) would be encountered during construction. Accordingly, an Acid Sulphate Soil Management Plan (ASSMP) was prepared in accordance with EPA guidelines and submitted as part of the approval process.

The remediation works required to construct the stormwater detention basin involved:

  • Neutralising the fish farm water pH prior to discharging into the adjacent water course.
  • Excavation of 43,500m3 of earth wall containing PASS material to a dedicated onsite containment cell.
  • Blending PASS materials with lime, then testing to ensure compliance with EPA Waste classification guidelines.
  • Compacting the blended materials within the containment cell.
  • Providing a protective capping layer over the containment cell utilising approved materials.
  • Reinstate natural topsoil and revegetate.   

By obtaining the required approvals, such as the Controlled Activity Approval and Construction Certificate, to complete the environmentally sensitive works, Monteath & Powys ensured the treatment and containment of the PASS materials remained onsite. The costly alternative of carting and disposing large quantities of PASS materials at a licenced waste management facility was not a feasible option. With the remediation project successfully completed within a 6-month period and Practical Completion granted by the consent authority shortly thereafter, the Client was appreciative of outcome with minimal cost and no project delay.

Other significant remediation management projects undertaken include:

  • Mines Subsidence
  • Asbestos – Friable and solid/ fragments
  • General Solid Waste
  • Industrial Waste
  • Hazardous Waste