Managing trees and the natural environment
Melbourne is recognised for the tree-lined streets, parks and open spaces that contribute to the liveability of our city. We are committed to minimising impacts on these important community and environmental assets.
Ahead of major construction ramping up in 2018, Managing Contractor John Holland is delivering a package of works that includes the relocation of more than 100 underground utility services such as water, gas, electricity and telecommunications, construction of access shafts in the CBD, as well as site preparation works.
Managing tree impacts
In preparing for major construction of the Metro Tunnel, some trees and vegetation will need to be protected and others removed.
Expert arborist advice will be called upon to firstly maximise tree retention, and where trees are protected on site, to develop and oversee implementation of Tree Protection Plans. These plans will be developed in accordance with local council tree management and removal policies, Australian Standards for Protection of Trees on Development Sites (AS4970-2009), and Pruning of Amenity Trees (AS4373-2007), and the arboriculture Environmental Performance Requirements (EPRs) developed for the project.
Where trees are required to be removed, only those necessary for the works undertaken ahead of major construction will be affected.
Some of the recommended EPRs for tree and vegetation management include:
- During detailed design, review potential tree impacts and provide for maximum tree retention where possible
- Prepare and implement Tree Protection Plans for each precinct
Measures for tree and vegetation management include:
- Implementation of Tree Protection Plans for construction works located in Tree Protection Zones.
- Arborist supervision during works within Tree Protection Zones
- Using fencing to provide both visual and physical barriers and protection for trees
- Site inspections and audits of measures in the Tree Protection Plans
- Avoiding using public open spaces where possible for temporary uses such as car parking, site offices and stockpiling locations
- Ongoing consultation with local councils and other government agencies to agree on tree removal requirements and processes.
Managing open space
To minimise the acquisition of private properties required for the Metro Tunnel, some public open spaces will be temporarily occupied as construction work sites.
A number of options were carefully considered through the planning process and sites include:
- the City Square in the CBD
- part of University Square in Carlton
- Albert Road Reserve in South Melbourne
- part of the Shrine of Remembrance Reserve near St Kilda Road
- Edmund Herring Oval, and
- the South Yarra Siding Reserve.
At the end of construction works in an area, parkland and open spaces no longer needed by the project will be returned to a condition equal to or better than their condition before construction started.
As the project progresses, every effort will be made to reduce impacts on vegetation including the review of designs to minimise the number of trees needing to be removed.
In the Parkville and Domain precincts, where it is expected a number of trees may be need to be removed to accommodate the new stations, Melbourne Metro Rail Authority and the appointed major works contractor will work closely with local councils to determine the size, species and placement of new trees.
We are looking at ways to protect, replace or offset trees at a ratio of two trees for every tree removed.
By the time the Metro Tunnel project is complete, at least 900 trees will have been replanted and they will be in better growing conditions. These conditions will be created by installing irrigation and other water sensitive urban design treatments and the use of structured soils. In some places, tree re-planting will commence during the construction period.
Opportunities will also be identified to improve landscape quality, amenity and tree canopy cover at a number of parks and reserves across the project.
Environmental Performance Requirements
A number of mitigation measures were identified in the EES to avoid, reduce or offset environmental impacts. These measures form the basis of the recommended Environmental Performance Requirements (EPRs) for the Metro Tunnel project and have been recommended by specialists through the EES process.
The EPRs define the outcomes that must be achieved during the design, construction and operational phases of the project. This approach is designed to ensure the project delivers a net benefit to the community, and in the process, encourages innovation and flexibility from the construction contractor in how they meet these requirements. EPRs relevant to this package of works will be implemented through contractual agreements with John Holland.