Home > Soils > Acid sulfate soil > Activities that damage acid sulfate soils

Acid sulfate soil

Activities that damage acid sulfate soils

The most common activities that trigger oxidation and generation of acid from acid sulfate soils are:

Drainage for agricultural activities and works to prevent flood and tidal inundation (levees, drains and floodgates) and the use of groundwater. Common industries in acid sulfate soil areas include sugar cane and tea tree cultivation, dairying and other grazing, cropping and aquaculture.
Infrastructure works especially flood management (levees, floodgates) drainage works, maintenance dredging, laying of utilities (water, sewerage, communications), roads and railways.
Urban and tourism development, e.g. for housing, resorts and marinas.
Extractive industries - sand and gravel extraction from rivers or floodplains.

Although all activities that cause the oxidation of acid sulfate soils are important, management practices of the past such as drainage, and tide and flood mitigation works for agriculture have contributed most to the current environmental problem in NSW.

Floodgates like this one at Leddys Creek (Tweed River region) were built to prevent flooding, but they can also cause oxidation of acid sulfate soils. Photo: Peter Haskins.

Water tables can also be lowered naturally due to seasonal fluctuations and drought in backswamps and backplains that are isolated from tidal waters.

However, human intervention, particularly construction of flood-gated drains in agricultural areas, has facilitated drainage from backswamps and other areas of acid sulfate soil. Drainage works have increased both the frequency of lower water tables and the total area of land affected.

Drains also increase the frequency and rate of discharge of oxidation products from areas of acid sulfate soil by providing conduits from backswamps to rivers and streams. Large volumes of acid may be stored in the soil or in groundwater and displaced from the backswamps into drains and coastal streams by rainfall.