Acid sulfate soils (ASS) are natural sediments that contain iron sulfides. They are common along low lying areas adjacent to waterways (typically where the surface elevation is less than 5m above mean sea level). If left undisturbed, ASS do not present any risk, but when exposed to air the soil reacts with oxygen to create sulfuric acid which can damage built structures, reduce agricultural productivity of land, and harm or kill animals and plants.
A large scale map showing the distribution and potential for Acid Sulfate Soil can be accessed below.
Acid Sulfate Soils (ASS) in the Coffs Harbour Local Government Area(PDF, 644KB)
More detailed mapping can be viewed using Council’s Online Mapping Tool. Select the ‘Planning & Environment’ module and ‘Acid Sulfate Soil’ layer. The class levels (1-5), represent the risk level with class 1 presenting the highest risk of ASS.
Access the Online Mapping Tool
Under Clause 7.1 of Council’s Local Environment Plan 2012 development consent may be required for certain works on land classed 1, 2, 3, 4 or 5 for ASS.
See descriptions for each of these classes below.
Works below the ground surface
Works beyond 1 metre below the natural ground surface
Works beyond 2 metre below the natural ground surface
Works by which the watertable is likely to be lowered beyond 2 metres below the natural ground surface
Find out how to seek consent via a Development Approval.
During the development application process, you will generally be required to engage a suitably qualified environmental consultant to undertake a preliminary assessment of the site.
This assessment report will be submitted to Council confirming the presence or absence of ASS.
If ASS are present and require remediation, the suitably qualified environmental consultant will need to develop a management plan to outline steps required to ensure the soil is appropriately managed.
Council has developed a process where applicants proposing only minor works on ASS land can develop their own management plan. This replaces the need to engage a consultant and reduces the costs and regulatory burden for applicants proposing only minor projects with a low ASS risk. Development consent will still be required.
If your proposal is one of the following, it is considered ‘minor’:
If you are proposing minor works on Acid Sulfate Soil land, you can develop your own management plan using Council's online form below. Simply fill in the project specific details.
Please take care to read and understand the management section which outlines the required process and liming rates.
Acid Sulfate Soil Management Plan for Minor Works
If you have any questions, call Council on 02 6648 4000.
If you can demonstrate the land has been lawfully filled, and any excavation will not extend below the depth of the fill, an Acid Sulfate Soil Management Plan is not required.
Evidence of this will be requested during the Development Application process if this applies to your proposal.
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