Project Update June - Sand Nourishment via Dredging Project to address coastal erosion at Port Beach

Seawall protection at Port Beach

In addition to the sand nourishment via dredging program, WA Limestone have been engaged to construct a new section of temporary seawall fronting the unprotected stretch of the Port Beach Carpark. The works will reuse the large rocks stockpiled in the Sandtrax car park, collected during phase 1 of the project. Due to the busy market and WA Limestone’s current commitments, works are scheduled to commence in early July 2022.

Project Update June 2022

In December 2021, phase 1 of the sand nourishment via dredge project was completed. This comprised of sand screening for rocks along the beach between Sandtrax and 200 m south of Tydeman Road and removal of the remnant seawall. The project working team comprising the City of Fremantle, Fremantle Ports and Department of Transport, have since been working through the approvals and procurement process to progress phase 2 works.

Phase 2 of the project involves:

• the supply of up to 150,000m³ of sand for beach nourishment at Port Beach between Sandtrax and Coast restaurant;
• sand dredged from the Fremantle Port’s Deep Water Channel will be placed into the nearshore at Port Beach by “rainbowing” methodology;
• the works are likely to commence in July 2022 and be completed in October 2022. This will be followed by approximately 4 weeks of dune creation stabilisation, and revegetation in Spring 2022.

Contractor negotiations for Phase 2

Negotiations with the preferred Contractor for the Dredging and Sand Nourishment works, are progressing and works are expected to commence in July 2022. It is anticipated that the works will progress over approximately 4 months due to dredge availability and other considerations such as tides, and weather conditions.

Once the preferred contractor is appointed, the preferred methodology for placing the sand on the beach will be finalised. A Trailer Suction Hopper type dredge will be employed and it is likely the material will be placed onto the beach via rainbowing. An image of this method is provide below.

Rainbowing methodology

Environmental Approvals and Management

A full Environmental Impact Assessment (EIA) has been completed for the project. Importantly, the EIA has determined, that based on the best practice environmental management plans that we have in place, any environmental impact is not expected to be significant.

The impact assessment has been informed by a number of required environmental investigations, including;

1. sampling of the sand sourced from the Deep Water Channel;
2. mapping of seagrass and benthic habitats;
3. dredge plume modelling; and
4. sand transport modelling.

These studies, along with the EIA and environmental management plans, were submitted to the Environmental Protection Agency (EPA) for their review in late 2021. The EPA has since determined that the environmental effects of the proposal are not so significant to warrant a formal assessment and approval has been granted.

Key management plans and mitigating key risks

Two key environmental management plans have been prepared:

The dredging environmental management plan - includes measures for monitoring and management of key environmental factors during the works including water quality, seagrass and benthic habitats. As part of this plan, seabed light levels, water quality and water clarity will be monitored during the dredging and sand nourishment works. Deployment of monitoring equipment will in June, prior to nourishment works.

The coastal processes monitoring and management plan - includes measures to monitor the movement of the sand placed in the swash zone, along the beach, ensuring that it is behaving as expected. This is likely to see sand placed on the beach, moved onto shore over a couple of summer and winter seasons.

Movement of the placed sand over the coming years will ultimately depend on weather conditions, which can be variable, so this plan allows for the actual movement of the sand to be traced. This plan is largely based on the City of Fremantle’s existing coastal monitoring program, supporting a cost effective approach.

For more information on the EIA and environmental management plans – please visit the project website

Stay Informed or for further enquiries

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Alternatively, please contact the City’s Customer Service Line on 1300 MY FREO (1300 693 736) or you can email info@fremantle.wa.gov.au or ask a question at https://mysay.fremantle.wa.gov.au/port-beach