Location: Brisbane, Queensland
Site size: 60,000m2
Delivered: March-December 2012
Legacy Way is Brisbane City Council’s 4.6-kilometre tunnel that will connect the Western Freeway at Toowong to the Inner City Bypass at Kelvin Grove. The Groundworks team is delivering an incremental Ecoblanket program, working in close collaboration with the client, Transcity, and the environmental managers, RPS.
While a generic organic blanket had been specified, the experts at RPS emphasised the value that Ecoblanket would provide. Early success led to new areas, not part of the original specifications for Ecoblanket, being included in the team’s overall scope of works.
Superior environmental results have generated additional financial value to the client including:
- Immediate erosion control – through the staged delivery process, the project has never had uncovered soil in areas contracted to Groundworks, with the team able to cover many thousands of square metres per day.
- Cost savings – there is no maintenance required, additional savings via long-term benefits and added value through carbon offsets; it has been estimated that traditional methods for the project would have cost up to three times that of Ecoblanket.
- Environmental best practice – the project has reported strong environmental results since the application of Ecoblanket.
One of the innovations was developed through RPS, Groundworks and the native seed expert consulting on Ecoblanket. They designed three different seed mixes tailored to suit varying height limits across the project. For example, vegetation closer to the road is designed to 2-metre heights, compared to areas further away, which reach 10-metre heights. Collaboration and careful program management have proven the success of this approach.
The site has achieved exceptional results in the strike rate of cover crop, up to 99%, and native species flourishing, with an average of five plants per square metre. It has stabilised very poor soils with less than 0.5% erosion. This is a major achievement considering the particularly long slopes on the site. Ecoblanket has controlled erosion and prevented any water runoff issues.