Castledine Gregory Law and Mediation

Developments on Acid Sulfate Soils: Managing your Risk


Developers whose proposals may impact Acid Sulfate Soils (ASS) must comply with additional pre- and post-approval requirements. This will inevitably add to the time and costs associated with the development.


This is especially the case if the development involves:

  • any dewatering or drainage works
  • the excavation of more than 100 cubic metres of soil, or
  • the development of a marina, boat harbour or canal estate.


The common pre- and post-approval requirements relating to ASS include:

  • the submission of an acid sulfate self-assessment form
  • undertaking preliminary and detailed site investigations
  • obtaining the approval investigations reports and an ASS management plan from Department of Environment Regulation, and
  • ongoing compliance with the ASS management plan.


Understandably, reducing the additional time and costs associated with addressing the risks associated with ASS is often a priority for developers and their consultants. However, it is important to balance this priority against the consequences of ASS not being adequately managed.


In the event that the development causes environmental harm, such as the contamination of groundwater by acid, arsenic and heavy metals, the Contaminated Sites Act 2003 (CS Act) may be applied.


Should the CS Act apply, the development site is likely to be classified under that statute, which may impact the value of that land and even preclude the use of the development. Following that classification, developers, land owners, occupiers and polluters (which can include consultants) may be required to undertake investigations and remediation works, on both the development site and any other properties impacted by the acid sulfate contamination.


In the event that the disturbance of ASS has off-site impacts, liability for negligence and nuisance may also arise.


As such, whilst the planning process for developments which disturb ASS can seem onerous, bear in mind the myriad of consequences for the development, developers and consultants if things go wrong.


For more information, contact Castledine Gregory.