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Acid Sulfate Soils
ASSMAC ASS Manual 1998 + Acid Sulfate Soils Assessment Guidelines
When it triggers
Site mapped as Acid Sulfate Soils risk Class 1-5 under Council ASS map.
When it doesn't apply
Site not on ASS risk mapping (typically inland; uphill).
Report required
Acid Sulfate Soils Management Plan (ASSMP) — if Class 1-2 risk
Produced by
Geotechnical Engineer / Environmental Scientist (CEnvP)
Indicative cost
A$2,000–12,000
Key output fields
- ASS Class (1-5)
- Soil pH (laboratory analysis)
- Potential acid generation
- Excavation depth + volume affected
- Treatment / neutralisation method
- Disposal route for excavated ASS material
- Groundwater management
- Monitoring program
Design implications
- ▸Pier/pile foundations preferred over slab (less excavation)
- ▸Stockpiled ASS soil must be lime-treated or contained
- ▸Groundwater pumping requires neutralisation
- ▸Construction sequencing to minimise excavation
- ▸Permanent dewatering avoided
Per-state notes
NSW: ASS clauses in most coastal LEPs; SEPP Resilience and Hazards 4.6 (former SEPP 55)
VIC: Land Capability Statement under Cl 53.20
QLD: ASS Risk Map in coastal LGAs; State Planning Policy
Notes
Common in coastal NSW + QLD + low-lying VIC. Excavation cost can double if ASS treatment required. Pier foundations often the workaround.