| Project | 2021 Maintenance Dredging Project – Project Approvals |
| Client | Mid-West Ports Authority (MWPA) |
| Location | Mid-West, WA |
| Date | March to August 2021 |
| About the Project | O2 Marine was engaged by MWPA to deliver environmental approvals and conduct a project impact assessment for the 2021 Maintenance Dredging project. O2 Marine’s scope was commissioned in March 2021 with the timeline for assessment and approvals extremely tight with dredging activities tentatively scheduled for September 2021. O2 Marine conducted works as per contemporary EPA Technical Guidance.
The project was not a typical dredging program as it contained contaminated sediment management through onshore disposal, acid sulfate management of tailwater release, and nearshore placement of non-contaminated, natural sediments 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 further refined, investigated and subject to extensive stakeholder consultation, including the EPA and DAWE sea-dumping section. Following PIANC guidelines, nearshore placement 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 the identification of suitable beneficial uses, MWPA was 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. To complete the impact assessment and prepare documentation for referral under the EP Act, O2 Marine undertook a full desktop review of all technical investigations conducted to support the project, along with the available historical information. Based on the 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. before whale migration, during seagrass dormancy period and prior to the significant rock lobster recreational season). The dredging project has since commenced and is approximately 75% complete. All monitoring has indicated that predicted impacts are either greater than or equal to actual impacts. |
