Environmental and heritage considerations are a key priority for the METRONET 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 were continuously monitored during construction. To find out more about the project's environmental considerations, view the environment and heritage fact sheet.
Dewatering was 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 involved temporarily lowering the water table within the work area to allow soil to be excavated without it refilling with water. Once the soil was removed, a base slab was poured to seal the structures and the dewatering process ceased.
Dewatering was undertaken at High Wycombe and Bayswater as part of the dive structure works, and for the underground stations at Airport Central and Redcliffe.
To find out more about the dewatering process, view the dewatering fact sheet.
Fauna and flora
As the rail line is located almost entirely underground, the impact to the environment is minimal. During construction, the impact on vegetation and flora was reduced wherever possible through site layout design and construction methods.
Where clearing was required, the areas were inspected for fauna through ground searches and tree hollow inspections.
Excess fill management
Excess fill refers to the soil generated during tunnelling and station excavation works for the Forrestfield-Airport Link. The project will generate approximately one million cubic metres of excess fill during construction.
A number of initiatives to beneficially reuse excess fill from the Forrestfield-Airport Link are being investigated.
Transfer of soil from one site to another is routinely undertaken on land development and infrastructure projects in Perth and around Australia. Reuse of excess fill represents a sustainable approach to managing a valuable natural resource.
To date, approximately 25 per cent of the project’s excess fill has been used as engineered backfill on transport projects across Perth, including within the Forrestfield-Airport Link site, within two road interchanges on the NorthLink project and at the Kenwick Rail Freight Facility.