Environmental and heritage considerations are a key priority for the Forrestfield-Airport Link, and as such detailed planning occurred before any works began to ensure areas of significant environmental value were identified, managed and reported on.
Environmental Management Plans with appropriate measures and controls have been implemented and are continuing to be monitored during construction. To find out more about the project's environmental considerations, view the Environment and Heritage fact sheet.
Dewatering is required along sections of the Forrestfield-Airport Link to allow for the construction of underground structures, such as the station boxes and tunnel portals. The process involves temporarily lowering the water table within the work area to allow soil to be excavated without it refilling with water. Once the soil is removed, a base slab is poured to seal the structures and the dewatering process ceases.
Dewatering was undertaken at Forrestfield as part of the dive structure works, and for the underground station at Airport Central.
The process is currently underway at Redcliffe, with the dewatering target achieved in March and excavation now underway within the station box.
Dewatering at Bayswater will begin mid-2018 as part of the tunnel portal and dive structure works.
To find out more about the dewatering process, view the Dewatering fact sheet.
Fauna and flora
As the line will be located almost entirely underground, the impact to the environment will be minimal. During construction, the impact on vegetation and flora has been, and will continue to be, reduced wherever possible through site layout design and construction methods.
Where clearing is required, the areas are inspected for fauna through ground searches and tree hollow inspections.
Approximately 900,000 cubic metres of spoil will be excavated during the project, then tested and assessed for suitable reuse opportunities. The project has committed to diverting the majority of spoil from landfill by reusing the material offsite. Options include using clean sands and gravels for roads, land developments and noise barriers.
Through routine environmental investigations for the construction of Redcliffe Station, the PTA has discovered perfluoroalkyl and polyfluoroalkyl substances (PFAS) in the groundwater. PFAS are manufactured compounds that have been used in certain types of firefighting foams and a range of consumer products, including non-stick cookware, fabric treatments, furniture and carpet stain protection, and food packaging since the 1950s. Environmental contamination by PFAS is an emerging challenge worldwide, and in WA is starting to be reported at various sites.
The WA Department of Health (DoH) has advised that the PFAS levels found within the Redcliffe Station construction site and its immediate surrounds do not pose a health risk to members of the public. Read more about PFAS on our Redcliffe Community Zone page.