Cairns Harbour - Long Term Dredge Spoil Disposal Strategy

Ports North

Summary

The project involved preparation of a series of studies over many years, firstly into alternatives to sea disposal of dredge spoil (marine and terrestrial options) and then consideration of environmental and community issues associated with the dredging and approved sea dumping option. This early work established the preference for sea dumping, located a suite of suitable sea dumping sites located clear of coastal influences and remote from coral reefs, and established the foundations upon which all future permits have been based. Environment North:

  • co-ordinated engineering, environmental and statutory planning input to a disposal options analysis,
  • assisted in forming and operating a Technical Advisory and Consultative Committee, and
  • prepared recommendations for operation and monitoring.

In particular, Environment North (in association with marine specialists Hydrobiology) developed a set of impact hypotheses relating to the dredging and dumping operations and used this structure as the basis of the 5 year monitoring program. We have also subsequently assisted the Cairns Port Authority (now Ports North) with its Sediment Analysis Program and follow-up approvals.

 

In 2015 Environment North was appointed to join a team led by Flanagan Consulting Group to investigate terrestrial disposal options for dredge spoil as part of the Cairns Shipping Development (CSD)  Project. This followed a decision by the Commonwealth Government to prohibit sea dumping in the GBRMP. The resulting Options Study featured GIS-based site selection, site evaluation, and site suitability assessments. This part of the task was undertaken by Environment North. The Site Evaluation process involved a Multi-criteria Analysis of 14 potential sites using cost, environmental, social, and performance criteria.

The outcome was a decision by Ports North to investigate two sites in detail as part of the CSD Project EIS.

 

Innovation/Distinguishing Features

LTDSDS: Resolution of competing demands (environmental, cultural, financial and operational) and integration of stakeholder views. First ever 5 year GBRMPA permit obtained.

CSD Project: Use of GIS-based decision support tools to locate potential sites for land disposal of dredge spoil.