Flowchart for applying the Tasmanian Acid Sulphate Soils Code

I’ve produced a PDF flowchart to help people navigate through the Tasmanian Acid Sulphate Soils Code.

The Code is one of many in the 2015 Interim Planning Scheme used by all Tasmanian Local Councils. See the list of Codes including the ones for which I offer professional services.

Potentially acid sulphate soils or sediments are naturally-occurring materials which contain microscopic particles of dark-coloured (mainly iron) sulphides. The sulphides were formed by sulphate-reducing bacteria acting on original sulphate in sea water.

Environments favourable for their formation are oxygen-poor (reducing) conditions in former or present day mud flats and other low-lying or shallow submarine coastal areas. Some potentially acid sulphate soils occur at higher elevations.

When disturbed and exposed to the atmosphere, the sulphides in these soils or sediments re-oxidise to sulphates and produce sulphuric acid solutions. The acid mobilises metals in the soil which in turn can cause environmental or infrastructure issues at the disturbed site, or elsewhere if seepages flow into adjacent waterways.

Importantly, if these materials are left undisturbed, sulphate is not generated. This is the key to their management.

Undisturbed soils with the potential to form acid sulphate are called PASS. Once disturbed, they are Actual Acid Sulphate Soils (AASS). Collectively these materials are called Acid Sulphate Soils (ASS).

The Tasmanian Department of Primary Industry, Parks, Water and Environment (DPIPWE) has plenty of information on where ASS occur in Tasmania, and how to manage them (PDF document). You can also check online to see if land you are interested in is in an ASS zone.

Go to the state government website www.thelist.tas.gov.au. On the home page, click “LISTmap”; double click on the location of interest and continue to double click (or use the mouse wheel) to zoom in; click “Layers” at top right, then click “Add Layer +”. In the menu box that opens, scroll down to “Geology and Soils”, click on “Soils” and click on one of the four Acid Sulphate Soils (the circular green + icons”. You may need to zoom in further until the bands are visible. Drag the menu box out of the way (or close it). At top right of the screen, click on the tiny arrow in the Acid Sulphate Soils box to see the Legend and change the transparency.