Acid Sulphate Soil Investigation Triggers

In Queensland, the presence and management of acid sulphate soils (ASS) is a significant environmental concern given the state’s geography and coastal zones. Local councils and the state government have developed guidelines and policies to address the potential risks of ASS disturbance.
While specific triggers can vary slightly between councils based on local conditions and priorities, many councils in Queensland refer to or adopt guidelines and maps provided by the state government. Here are some common triggers that might necessitate an ASS investigation in Queensland councils:

1. Known ASS Risk Zones:
The Queensland government provides ASS risk maps that delineate areas with a high likelihood of containing ASS. If a proposed activity is within one of these mapped areas, it’s a primary trigger for an investigation.

2. Depth of Ground Disturbance:
Activities that involve excavation or disturbance below a specified depth, often around the natural water table (e.g., 1-2 meters in some areas), can prompt an ASS investigation. The rationale is that such disturbances could expose potential ASS to oxygen, starting the acidification process.

3. Water Management Activities:
Proposals that could impact the groundwater or surface water table, such as drainage modifications, dewatering, canal constructions, or dam developments, may require ASS investigations.

4. Land Use Change in Risk Areas:
If a site within an identified risk area is transitioning from one land use to another, especially if the new use could disturb ASS (e.g., converting wetlands to agriculture), an investigation might be triggered.

5. Volume of Soil Disturbance:
Some guidelines might specify a volume threshold for soil disturbance. If you’re moving or excavating beyond this volume in a potential ASS area, an investigation may be needed.

6. Proximity to Sensitive Environments:
Activities near ecologically sensitive environments, like mangroves, wetlands, or coral reefs, might trigger an investigation due to the potential environmental impact of acid leachate.

7. Infrastructure and Development Projects:
Projects that involve extensive groundworks, especially below-ground structures like basements or tunnels, in potential ASS regions can trigger investigations.

8. Previous Reports of ASS:
If nearby areas or adjacent sites have confirmed ASS issues or if historical ASS disturbances have been reported, an investigation might be triggered for new activities.

9. Public or Community Concerns:
Occasionally, local knowledge or community advocacy can be a trigger, especially if there’s a strong public sentiment or historical context for ASS disturbances in the region

As an example, listed below are some council guidelines.

Brisbane City Council:
• Areas identified as having a high or moderate risk of containing ASS in council maps.
• Disturbance or excavation of 100 cubic meters or more of soil.
• Disturbance or excavation below a depth of 2 meters from natural ground level.
• Water table changes, such as drainage or filling, in high or moderate risk areas.

Moreton Bay Council:
• Areas mapped as potential ASS regions.
• Disturbance or excavation of soil from below the natural water table level.
• Activities that could alter the water table, potentially exposing ASS.
• Any development or activity that might disturb a significant volume of soil or go beyond a specific depth in identified risk areas.

 Redland City Council:
• Development or ground-disturbing activities in areas mapped as potential ASS risk zones.
• Excavation or disturbance below a specified depth, often linked to the natural water table.
• Activities that change the hydrology, potentially exposing submerged ASS to oxygen.
• Large-scale developments or earthworks in regions identified as having ASS potential.

These are general triggers that might be applicable, but they can change based on new research, findings, and council decisions. For the exact, current requirements, I would recommend consulting the planning and environmental guidelines provided by each individual council or reaching out to the council’s environmental or planning departments directly. They can provide specific documents, maps, and guidelines detailing the triggers for ASS investigations in their respective regions. A link to the Queensland ASS guidelines can be found here.

If you would like to discuss your Acid Sulphate reporting requirements please get in touch here.

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IF you require a site classification for your plumbing work, you may also then be required to provide an articulation report detailing connections designs specifically for that site. Any site that is classified A, S or M does not require an articulation report. Those sites classified H1, H2, E or P will be required to submit a site classification report and articulation report to council to gain approval for their plumbing application.

It is important to note that completing plumbing work prior to receiving a site classification report may result in plumbing work being dug up and modified. This would occur in the event of poor site conditions being recognised in a subsequent site classification report.

If you require site investigation and classification for your plumbing application or would like to know more please feel free to contact us at any time. We are also able to help with the articulation report requirements for those whose sites require it.

The post Soil Testing For Plumbing Applications first appeared on Express Soil Testing.

Soil testing and site classification is conducted to identify a variety of issues which must be considered when planning to build on a specific site. Reduced bearing capacity is a problem that must be recognised and addressed. This is a common issue in Brisbane where many suburbs are built on natural clay deposits.

Where a site is to be built on clays, the same moisture susceptibility that caused shrinking and swelling of clays also reduces their capacity to bear weight. As these clays absorb water, they become soft, much like playdough. When a load such as a footing or foundation is applied to these soft, low bearing capacity soils, the foundations move and affect the stability of the building. Damage may occur as a result.

It is not uncommon to see fill brought to a site that contains a significant amount of clay. Often this material is placed over what are otherwise stable local soils. It is possible in this situation to “import” problems to your site when utilising uncontrolled fill. This problem can be avoided by utilising controlled fill for which engineering properties are known.

The post Potential Issues Identified in Soil Testing and Site Classification – Bearing Capacity. first appeared on Express Soil Testing.

The post Why do I need a Soil Test? first appeared on Express Soil Testing.