Swan River Pedestrian Bridge Environmental Management
When completed, the Swan River Pedestrian Bridge will be an asset for the community to be enjoyed year round. It is important that the river and adjacent environment is respected and protected during construction and throughout the life of the bridge. The environmental and cultural significance of the Swan River and responsible management of our waterways is also very important.
Extensive consultation with key stakeholders including the Department of Parks and Wildlife, the Whadjuk Working Party, Department of Environmental Regulation, Department of Transport Marine, and the local community, was undertaken during the planning stages of the project and in the preparation of the Construction Environmental Management Plan (CEMP).
Detailed investigations have been undertaken to ensure that any impacts from bridge construction during all stages of work will be minimised and managed responsibly.
Protection of marine fauna and river quality is a primary focus of the CEMP. Monitoring of water quality and underwater noise and vibration levels will be undertaken to ensure that marine fauna are not adversely impacted by construction activities.
Of particular significance is the local population of Indian Bottlenose Dolphins in the Swan River. They frequently travel up the river and are seen in the area where there will be construction activity. Trained observers will monitor the bridge construction activities, and if curious dolphins come too close, works will stop.
Historical land uses of the Burswood Peninsula and East Perth foreshore included import of soil from unknown sources, so the site may be contaminated. Any soils removed for the project will either be managed on site or disposed of at an appropriate landfill facility and replaced with clean soil.
Acid sulfate soils
Acid sulfate soils (ASS) are naturally occurring soils formed under generally waterlogged conditions that if exposed to oxygen (i.e. if excavated) can acidify.
ASS occurs in many areas of Perth and are expected at the site. While the project has been designed to minimise the potential to intersect ASS, should it be disturbed ASS will be stored in a controlled dedicated stockpile area and either treated or taken off-site to a licensed facility.
The Swan River is a major heritage site. There are also three other heritage sites situated in or near the Project area.
We will engage Aboriginal monitors to observe works of significance to ensure that cultural heritage is respected.
Water quality testing is essential to ensure the health of the river and protection of river fauna. Regular testing will be undertaken during construction activities and results will be regularly reported to the Department of Parks and Wildlife and the Department of Environment Regulation.
Erosion and sediment control
The river will be disturbed as little as possible during construction of the pedestrian bridge. Erosion and sediment controls have been designed to prevent surface water, soil or construction material entering the Swan River.
Two 130m causeways of 50m and 54m widths respectively will be constructed on either side of the river to create construction and assembly platforms. The causeways will be established within the riverbed using a rocky granite material to form an outer bund and finer granite material for the inner fill. Double layers of silt curtains will be installed in the river before construction works within the river start and a third silt curtain will be installed during construction and removal of the causeways.
Details of the construction of the temporary causeways and installation of silt curtains are contained in the Construction Methodology fact sheet.
We will monitor air quality throughout the course of the Project to ensure works are not generating dust in excess of environmental regulations.
Noise and vibration
All construction activity will generate some noise and most machinery will also cause vibration at some stage. Piling activity, similar to that undertaken for the Stadium will also cause some vibration. Ground and underwater vibration monitoring will be undertaken at regular intervals, in particular at the start of each new phase of construction.
Every effort will be made to minimise noise and vibration impacts. We will also ensure that all equipment, machines and vehicles on-site will be the quietest available.
Where required, pre-construction surveys will be undertaken prior to the start of construction. This will involve a professional, independent building surveyor photographically recording the current condition of identified structures. Following the survey, the findings are recorded and provided to the owner in a report. In the unlikely event that there is any damage as a result of construction, the survey report will be used as a reference to determine the extent of the damage. Residents whose homes are situated within the identified area will be contacted directly.
The landscaped areas on both sides of the bridge will be enhanced by planting native vegetation and trees when construction is complete. The revegetation is being planned and implemented by a professional landscape architect and will create an appealing urban landscape area as
part of the journey to the Perth Stadium. We have worked closely with the Department of Parks and Wildlife and other stakeholders to ensure the revegetation design benefits both the environment and community.