Sorell Causeway Upgrade

Client: Department of Infrastructure, Energy and Resources

A 900 metre causeway realignment and 14 span bridge replacement at Sorell Causeway was planned to be undertaken by Shaw Contracting. The grade would result in the removal of critical habitat for the Live Bearing Sea Star (Patiriella vivipara). Environmental Approvals, impact mitigation and advice was sought prior to works being undertaken.

Key Issues included the loss of critical habitat for the sea star and strong community interest in the waterways. In addition, the adjacent waterway was a listed RAMSAR wetland and unmitigated impacts were likely to be significant.

Project components included the preparation of referrals and preliminary documentation for assessment by the Federal Government under the Environment Protection and Biodiversity conservation Act 1999.

Conservation Volunteers at work

Conservation Volunteers at work

Project approvals required the management of potential impacts during construction and the requirement for removal of the sea stars from habitat which would be destroyed. The approval required new habitat to be created during construction. Plans were developed for habitat reestablishment and replacement of the sea stars in the new habitat was undertaken.

Removal of the sea stars was undertaken by Conservation Volunteers under the direction of Millin EMS. Monitoring and reporting was undertaken by Millin EMS as required under the project approvals.


Site specific silt control measures included:

  • extension of basal geotextile layer for silt retention,
  • inward sloping earthworks and,
  • rock filter drainage funnels.

The use of these construction techniques resulted in minimal silt loss to adjacent waters.

Millin EMS also conducted routine audits of construction activities enabling site issues to be managed as they arose.

The project resulted in the successful establishment of habitat for the Live Bearing Sea Star.