Remediating and managing coastal acid sulfate soils using Lime Assisted Tidal Exchange (LATE) at East Trinity, Queensland

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Bush, R, Ahern, C, Powell, B, Smith, D, Martens, M, Sullivan, L, Wang, Z, Taffs,K, Burton, E, Wilbraham, S, & van Heel, S 2018, Remediating and managing coastal acid sulfate soils using Lime Assisted Tidal Exchange (LATE) at East Trinity, Queensland, CRC for contamination assessment and remediation of the environment : technical report no. 4, CRC Care, Newcastle, Australia. ISBN 9781921431609

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This report reviews the implementation and associated research activities of a successful coastal acid sulfate soil (CASS) remediation strategy. East Trinity is a case study of how a severely degraded tidal wetland has been returned to a functional estuarine habitat using a cost-effective, low technology method based on the reintroduction of tidal water. The East Trinity experience is a reference point for best-practice remediation and management of broadacre CASS and is an exemplar conversion site linked to the National Standards for Ecological Restoration.

The remediation strategy known as lime assisted tidal exchange (LATE) was implemented in 2001 following a comprehensive site and operational methodology assessment. An initial trial of LATE proved successful in terms of the water quality and soil parameters. The short time period in which these parameters responded prompted the need for a research program aimed at understanding the interaction of daily tidal inundation and an acidified soil landscape. This research showed that LATE’s success can be attributed to the combination of an alkaline input alongside a huge flush of organic matter. The East Trinity site now has sufficiently high ecological function to transition from active to passive management. Under passive management, the addition of hydrated lime to the waterways ceases, and regular tidal inundation will remain in place to ensure that ASS remain protected from further oxidation.

Additional information

The Project Team especially wishes to acknowledge the key role of Dr Hanabeth Luke (SCU) and Dr Ellen Moon, Dr Scott Johnston and Dr Nicholas Ward from Southern Cross GeoScience (SCGS).