Geraldton Port Maintenance Dredging

Project Geraldton Port Maintenance Dredging
Client Midwest Ports Authority
Location Geraldton, WA
Date March 2021 – Current
Our Services O2Marine was engaged by MWPA to deliver environmental approvals and conduct a project impact assessment for the 2021 Maintenance Dredging project. O2Marine’s scope was commissioned in March 2021 with the timeline for assessment and approvals extremely tight with dredging activities tentatively scheduled for September 2021. O2Marine conducted as works in accordance with contemporary EPA Technical Guidance.

The project was not a typical dredging program as it contained both contaminated sediment management disposed onshore as well as nearshore placement of natural sediments which were identified for beneficial re-use within the existing Champion Bay Sediment cell. A thorough beneficial uses assessment was conducted in accordance with PIANC guidance and the London Protocol which identified these two options. These options were then further refined, investigated and subject to extensive stakeholder consultation, including the EPA and DAWE sea-dumping section. Nearshore placement, in accordance with the PIANC guideline was identified due to the potentially significant ecological benefits these sediments could provide through relocation within the Champion Bay Secondary Sediment Cell and was widely supported during the stakeholder consultation program. Through identification of suitable beneficial uses MWPA were not required to apply for a sea-dumping permit as the exercise was considered placement with a purpose and thereby did not contravene the London Protocol.

O2Marine also provided technical studies to support assessment, including sediment quality and Benthic Communities and Habitat (BCH) surveys, as well as dredge monitoring of water quality. O2M are also engaged to conduct a post dredging BCH survey scheduled for March 2022.

Outcome To complete the impact assessment and prepare documentation for referral under the EP Act, O2Marine undertook a robust desktop review of all technical investigations conducted specifically to support the project, along with historical information available. Based on identification of suitable mitigation tactics, such as avoidance and management, the project was not identified to warrant referral as there were no ‘Significant’ environmental impacts predicted from project activities.

Based upon the thorough impact assessment and project technical investigations, the MWPA Board elected not to refer the project as this may potentially result in commencement delays which would inadvertently result in missing the most suitable environmental window as identified through the impact assessment and stakeholder consultation process (i.e. prior to whale migration, during seagrass dormancy period and prior to the significant rock lobster recreational season).

The dredge project has since been completed with all water quality monitoring to date indicating that the Environmental Protection Outcomes for the Project were met. Outstanding post dredge surveys include benthic habitat surveys and ongoing beach profile surveying.

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