Acid sulfate soils are natural sediments that contain iron sulfides. When disturbed or exposed to air these soils can release acid and other heavy metals, which can have severely damaging effects on aquatic ecosystems.
Council continues to address the remediation of a State recognised acid sulfate soil (ASS) hotspot through the staged implementation of the Big Swamp project.
The Big Swamp is a 2000 hectare coastal floodplain at Coralville which has been extensively cleared and drained for agriculture.
This has resulted in the generation and discharge of ASS pollution into the Manning River Estuary, which has adverse impacts on water quality, aquatic ecology, oyster production and commercial and recreational fishing.
With funding provided through the NSW Estuary Management Program and Council’s Environmental Levy, Council has recently purchased an additional 170 hectares of ASS affected land, building on the 700 hectares of land already acquired and remediated through the project to date.
Remediation activities have included extensive drain modification works to reinstate the natural hydrology of the landscape and introduce tidal flows to reduce the amount of acid runoff entering the River.
As a result of the works, both saltwater and freshwater wetlands are now re-establishing at the site and improvements in water quality are already evident.
The newly acquired land is also high in biodiversity value with a recent vegetation survey discovering a significant population of the endangered plant Noah’s False Chickweed growing on the site.
The acquisition of this land complements work undertaken at Cattai Wetlands, where an additional 500 hectares of land have been remediated and has also been instrumental in securing into public ownership a regional wildlife corridor which links habitat within the adjoining Crowdy Bay National Park to the forests of the Lansdowne escarpment.