Water Journal : Water Journal September 2012-1
sustainable water management water SEPTEMBER 2012 85 more flexibility and an opportunity to use alternative construction techniques. The final alignment enabled the Alliance to retain the majority of the significant habitat trees using different construction techniques (Figure 4). The trees that were retained are large, mature, hollow-bearing koala-habitat trees that, apart from fauna habitat, also provide aesthetic value and a buffer to the residents living along the road (Figure 5). The efforts of the Alliance were recognised and appreciated in the local media by the community (Figure 6). This approach has achieved the following important sustainability outcomes: • The retention of over 300 signifcant habitat trees within the construction corridor and the clearing of only 640 trees of lower ecological value (as opposed to the originally estimated 1,800 destined to be cleared). This outcome was achieved by: -- boring under trees -- using smaller excavators wherever possible -- reducing the construction footprint along the alignment by minimising the clearing corridor, wherever possible, from 10 metres to 8 metres wide, resulting in a reduction of nearly one hectare in vegetation clearance; • Demonstration of the Alliance's commitment to reducing its environmental impacts to key program stakeholders, including the Australian Koala Foundation and Department of Environment and Heritage Protection (DEHP). This has helped the Alliance develop a strong working relationship with regulators, a relationship that is based on their confidence that the Alliance is genuinely committed to pursuing outcomes that limit its environmental impacts; this in turn facilitates effective approval processes; • Maintenance of a buffer between high-speed traffic and residential dwellings, resulting in significantly better community amenity for residents along the alignment; • Satisfaction of all DTMR requirements during design and delivery phases, thereby ensuring high-quality outcomes for public road infrastructure. Greenwood Lakes Reserve Rehabilitation Project In 2011, the Alliance identified a strategic approach to meeting its mitigation-offset requirements for vegetation clearance under the Nature Conservation Act 1992. The Alliance's environment team realised that the most effective way to mitigate the loss of vegetation on Alliance construction sites was to find a significant area of land to rehabilitate through additional vegetation planting, rather than by conducting rehabilitation activities on sites scattered across the Logan district. The majority of the Alliance's project sites do not allow sufficient space for on- site revegetation works because planting over the pipeline is not considered appropriate. Also, many Alliance projects are in the 'road reserve' of roads that are earmarked for future widening. Therefore, on-site planting often would not have provided a long-term sustainable solution. Working with Logan City Council and the DEHP, the Alliance identified a suitable site -- the 43-hectare Greenwood Lakes Reserve on the banks of Oxley Creek in Forestdale. This reserve is part of an important wildlife corridor between Brisbane and Beaudesert, but has been degraded by years of sand- mining activities. The main driver in the selection of Greenwood Lakes Reserve was the long-term environmental and community benefits that would be achieved by the mitigation work. This rehabilitation project indicates a substantial investment by Logan City Council in environmental sustainability and meeting its obligations under the Nature Conservation Act 1992. The Alliance developed a three-year management plan for the reserve (approved by council and the Department of Environment and Resource Management) and is now implementing the $1.9m first stage of rehabilitation activities, which includes rejuvenation of a 12-hectare section of the reserve through: • Propagation of 10,000 native plant seedlings; • Planting of more than 81,000 tubestock; • Installation of 34 nest boxes to provide habitat for local fauna. The benefits of the Greenwood Lakes Reserve rehabilitation project include: • Cost savings gained by managing a single mitigation site rather than multiple sites; • Cost savings gained by managing one subcontractor under one contract rather than multiple subcontractors under different contracts; • Improved relationships with DEHP assessment staff, which gave DEHP confidence that the Alliance would meet the vegetation-clearing permit conditions; this decreased the time it took to approve individual permits; Figure 5. Post-construction restoration. Figure 6. An article in the local media2. 2 Jimboomba Times, November 17, 2010.
Water Journal November 2012-1
Water Journal August 2012