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Acid-Sulphate Soils:

Please read the expert view on excavating acid sulphate soils in coastal areas by Tim Chamber, senior hydrogeologist.

All potential acid sulphate soil must be handled in accordance with:
New South Wales Acid Sulphate Soil Management Advisory Committee (August 1998) Acid Sulphate Soil Manual, ISBN 0 7347 0000 8

See extract scan of a page from the manual showing the situation.
Manual produced by
NSW Agriculture
Wollongbar Agricultural Institute
Bruxner Highway

The guidelines address management, laboratory testing, drainage and waterways, groundwater, management plans and industry.
An extract from Page 1 of the Groundwater section:
" In coastal areas underlain by potential acid sulphate soils, it is important to maintain the groundwater level above the potential acid sulphate soils layer so that it does not dry out. If the watertable drops below the top of this layer [Tim: or if the soils are excavated and place above the water table] air can enter the potential acid sulphate soils, oxidise them and produce sulfuric acid. After rain, the watertable rises [Tim: rain flushes excavated soil] and washes the sulfuric acid out of the oxidised sulphate soil layer. In undisturbed wetlands and lowlands, this acid water tends to remain in the areas and is gradually neutralised by the natural buffering capacity of the peaty and other material or is gradually diluted by additional rainfall. In areas where drains have been constructed, the acid can be quickly carried out of the area into waterways where it can kill fish and other aquatic organisms and reduce their habitat and breeding grounds. It is therefore essential that shallow groundwater in areas containing acid sulphate soils is managed to minimise the generation and transport of acid."
DNR acid sulphate soils page with many links: