Anna Bay Acid Sulfate Soil Assessments

In recent years there has been increasing awareness of the impacts of acid sulfate soils in the Anna Bay sub-catchment, which discharges into the Port Stephens – Great Lakes Marine Park. Greater movement of acidic groundwater has resulted in fish kills, poor water quality affecting oyster cultivation, reduced stock production and a deterioration in downstream environmental values.

This report provides the results of detailed on-ground assessments of the distribution and impacts of acid sulfate soils. These assessments included:

• a review of all previous studies
• water quality monitoring and chemical analyses
• collection and analysis of soil cores
• cross-sectional drain profiling
• digital elevation data (LiDAR)
• land surveys

The assessments identified the presence of acid sulfate soils across the catchment with two key ‘hotspot’ areas of soil acidity.

The report also identifies on-ground works that would be most effective at retaining high groundwater levels to manage acid export, while ensuring better drainage of surface waters following floods and severe rain events.