What has caused erosion in this area?
The Northbank foreshore shoreline is subject to erosion. Historical foreshore reclamation (or riverbank realignment) has altered the shape of the shoreline and the river is trying to establish a new shoreline position between its natural and modified location. The erosion is caused by a combination of waves (from wind and boat wakes), tidal currents and storm surge.
What area is included in this project?
The project boundary is included below.
This project is not looking at:
• Stabilisation works associated with the Rivershores mixed use apartment.
• Stabilisation works associated with the existing seawalls.
• Landscaping works of the foreshore.
• Stormwater drainage overflow from Rivershore’s Stormwater Infiltration Tank.
What process has been undertaken?
During stage one of the project a comprehensive review of technical reports and best management practices was undertaken. The aim of this is to understand the local environment and identify potential options to help stabilise the area.
In stage two the City of Fremantle and GHD have consulted with key state government bodies who have assets in or near the Northbank site to understand their future plans for the area and how any changes may impact them. We also provided information to local residents on the key issues and requested feedback on how they use this section of the Swan River and what they thought important for us to consider when designing options.
Concept development focused on foreshore stabilisation options. The complex nature of this project meant a number of factors have to be balanced, as well as considering any costs of potential remediation required to ensure contaminants below surface soil are not released into the environment.
Five stabilisation options have been prepared for community feedback.
What do we know about potential contaminants in the soil?
This area was historically used for a range of industry including wool scouring, steam laundering, boat repairs and slipway, which may have contributed to site contamination. The immediate foreshore is also at risk of being in or near an acid sulfate soil (ASS) risk zone within 3 metres below the soil surface. Soil sampling of any proposed areas to be disturbed would need to be carried out and a site investigation carried out prior to detailed design. This will depend on the option chosen as the level of soil that could be disturbed varies between the options.
What is the selection process for options?
Once draft concepts are prepared the process for selecting options will be:
- Community feedback received.
- Review feedback from community on options.
- Scoring of each option against key criteria.
- Options will be ranked according to the criteria scoring and criteria importance.
- Recommended option selected based on scores.
- Propose recommended option to Council.
- Selection of the preferred option.
- Detailed design
- Construction (subject to budget approval or funding).
The key criteria are amenity, environment, beach stability, land stability, and cost.