Comprehensive Acid Sulfate Soil Management Plans - Sydney
Proven Track Record in Fast, Accurate and Reliable Acid Sulfate Soil Management Plans
Acid Sulfate Soils (ASS) are a common risk across Sydney’s coastal floodplains, estuaries, and low-lying areas, including Botany Bay, Cooks River, Georges River, Parramatta River, and Sydney Harbour catchments. When disturbed by excavation, trenching, or dewatering, ASS can oxidise, generating acidic runoff, mobilising metals, and damaging concrete and steel.
Sydney councils frequently require an Acid Sulfate Soil Management Plan (ASSMP) as a DA condition where sites are mapped within Class 1–5 ASS risk zones.
Confluence Environmental prepares detailed, construction-ready ASSMPs for projects across Greater Sydney, ensuring compliance with NSW EPA and council guidelines, while remaining practical for supervisors and contractors to use on site.
What’s Included in a Sydney ASSMP?
Excavation & handling controls – staged excavation, segregation of PASS/AASS, immediate covering of exposed soils, lined and bunded stockpiles.
Treatment requirements – lime dosing rates derived from NATA laboratory analysis, onsite mixing methods, verification testing of treated materials, and record sheets.
Dewatering management – treatment train design (settlement → neutralisation → polishing), field pH/EC/turbidity testing, discharge criteria, and hold points.
Supervision protocols – clear instructions for site supervisors and environmental monitors, including checklists, inspection points, and contingency procedures.
Rainfall & runoff controls – containment, capture, diversion, and inspection hold points to prevent untreated discharges.
Waste & reuse pathways – guidance on reuse under EPA exemptions, or Waste Classification for off-site disposal.
Monitoring & reporting – regular site monitoring, verification sampling of treated soils, and close-out validation reports tailored for Sydney councils.
When Will Sydney Councils Ask for an ASSMP?
You will likely need an Acid Sulfate Soil Management Plan in Sydney if:
Your site is mapped in a Class 1–5 ASS risk layer (e.g. Botany Bay, Cooks River, Georges River, or Parramatta River floodplains).
Works involve excavation below the water table, trenching, bulk earthworks, or dewatering.
A DA information request or consent condition requires a site-specific ASSMP.
Related Services
Before a management plan can be prepared, councils may require a Stage 1 Acid Sulfate Soil Assessment or Preliminary Investigation. Confluence Environmental also provides:
Desktop reviews – council mapping, Section 10.7 Certificates, historical aerial photography.
Field investigations – boreholes, test pits, groundwater checks.
Soil testing – field pH, pHFOX, EC, and NATA-accredited laboratory analysis (SPOCAS, CRS, ABA/NAPP).
Risk assessments – identifying PASS/AASS zones and informing lime treatment requirements.
Learn more about Sydney Acid Sulfate Soil Assessments ➝
Why Choose Confluence Environmental in Sydney?
Sydney-based consultants experienced in preparing ASSMPs accepted by multiple Sydney councils.
Verification testing, supervision protocols, and practical controls included in every plan.
Plans written to be usable by supervisors, contractors, and engineers in the field.
End-to-end service: preliminary investigation → testing → management plan → verification and reporting.
Competitive pricing, transparent scopes, and responsive turnaround to meet DA deadlines.
📞 Call 0493 042 642 or request a fast quote for a Sydney Acid Sulfate Soil Management Plan (ASSMP) tailored to your project.
Why choose Confluence Environmental for Acid Sulfate Soils in Sydney?
Need an Acid Sulfate Soil Management Plan?
Sydney-based environmental scientists delivering Acid Sulfate Soil Management Plans, Verification Testing and Supervision. We make sure you’re DA-ready and cost-effective.
ASSMP for excavation, stockpiles & dewatering
Waste Classification, ENM/VENM & reuse pathways
Salinity/aggressivity inputs for designers
Call 0493 042 642 or Request a Fast Quote today.
Frequently Asked Questions
What are Acid Sulfate Soils?
Acid Sulfate Soils (ASS) are coastal and estuarine soils containing iron sulfides. When exposed during excavation or dewatering, they generate sulfuric acid, which can corrode concrete, mobilise metals, and pollute waterways. Sydney councils often require management plans where ASS is present.
When do I need an ASSMP in Sydney?
An ASSMP is usually required if your site is mapped in a Class 1–5 ASS risk zone, or if works involve excavation below the water table, trenching, bulk earthworks, or dewatering. Councils may condition it at DA stage.
What does an ASSMP include?
Plans outline excavation and handling controls, lime treatment, verification testing, dewatering management, supervision protocols, and reporting requirements so contractors meet DA and EPA standards.
Do I need an assessment first?
Yes. A Stage 1 Acid Sulfate Soil Assessment (desktop review, site inspection, lab testing) is normally required to confirm risks before preparing a management plan.
Where do you work in Sydney?
We service Greater Sydney, including Botany Bay, Cooks River, Parramatta River, Georges River, and Sydney Harbour catchments.