Gateway Project set to come in on time and under budget.
This billion-dollar Gateway WA Perth Airport and Freight Access Project received both state and federal government funding and is the largest infrastructure development undertaken by Main Roads WA. The goal was to facilitate efficient and safe transport around the fast expanding Perth airport as well as the Kewdale rail and road transport hub.
Many years of detailed planning has gone into the project and Main Roads has deep experience with projects such as construction of the Forrest Highway, Bunbury. Building on from previous success, an alliance was formed – essentially a project team, consisting of Leighton Contractors, Georgiou, GHD, AECOM and BG&E – working in partnership with Main Roads WA.
What contributed to the projects early and under budget completion? According to a Gateway WA spokesperson it was about ongoing project efficiencies such as effective management and subcontractors as well as favorable weather conditions. C-Wise was able to keep pace with the demand for composted product from their facility in Nambeelup. The shear logistical challenges of delivering bulk material in semi-trailers via a 160 kilometres round trip was daunting in itself. Over the fourteen months of the project 55,000 cubic metres were delivered to the project, which equates to 1,100 semi trailer loads.
C-Wise contributed by supplying composted mulch and soil improvement products. The largest proportion of product delivered, was a specific custom-made blend called the Gateway Revegetation Mulch. This is a dual-purpose mixture, which has both chunky and fine fractions. When laid on the surface it can be incorporated into the soil as a soil improver into which new plants can be placed. It also acts as a moisture saving mulch. Humiclay was also supplied; this is a concentrated high humus mature composted soil improver, which has Bentonite clay added to aid in moisture and nutrient retention. This was used for planting high value mature trees.
It was essential that any soil improvers or mulch materials introduced to the site be composted to ensure freedom from weed and disease organisms. Also mature soil carbon products are actually antagonistic to pathogens such as dieback disease.
The urban design features a “Ribbons through the landscape” theme, which draws from the natural Perth landscape setting and includes vegetation. With an overall footprint of 121 hectares there is an enormous requirement for landscaping. More than a million plants were added to the landscape including translocated grass trees and zamia palms.
There is a doubling up of environmental benefits here. Apart from the improvement of soil fertility and resilience at the project, all the mulch and soil improvers used are derived from waste materials. These have been rescued from going to landfill and converted into soil carbon solutions by a sophisticated, controlled composting system.
