Major construction work for the tram project will not begin until October, coinciding with the ACT election, according to the latest plans released on Thursday.
The news means that if the opposition Liberals win the October election, they would not have to reverse significant construction work, but they would still face the major expense of compensating the Canberra Metro consortium for cancelling the $698 million project.
Works approval documents released for comment by the National Capital Authority show construction is expected to begin at Flemington Road in October this year, with the main Gungahlin construction compound completed by the end 2016, along with earthworks and some roadwork.
The National Capital Authority has called for comment on the works application by March 18 and will hold a public information session in the city on March 1.
In its application, the ACT government says the project is not inconsistent with any of the Commonwealth's interests in Civic.
"It maintains the existing geometry of Civic, and respects City Hill as the symbolic apex of the central national area, and does not unduly interrupt any important vistas," it says.
Most of the early work focuses on Flemington Road – the Gungahlin end of the 12km route. Work on the Nullarbor Avenue intersection and the Gungaderra Creek rail underbridge is also scheduled for the end of 2016.
Between January and March next year, excavation begins on Flemington Road for tracks and overhead wires. By mid-2017 the major Flemington Road work is to be completed, including remodelling of eight of the 10 intersections.
The focus shifts to Northbourne Avenue from August 2017, when two work fronts will be open. By October 2017, intersections along the entire alignment are to be completed, according to the timetable put to the National Capital Authority.
Construction overall is to finish in late 2018 and the trams to begin operating in early 2019.
Also on Thursday, the Liberals' Brendan Smyth pointed to advice from the government's own Territories and Municipal Services Directorate that challenges the decision to plant new trees once they've reached 4m height.
The directorate told the Capital Metro Agency that eucalypts established and performed better if they were planted at a smaller height. The trees should be no more than 2.5m high, the directorate said.
The government has nevertheless insisted on 4m, and Capital Metro Minister Simon Corbell said while smaller trees might grow more quickly, planting them at 4m would not reduce their viability in any substantial way. The Canberra Metro consortium would have to replace any that failed with a tree of the same size, he said.
The inner row of trees along the corridor will be removed from October 2016. The outer row will removed from the middle of 2017, starting at the south, or city, end and moving north as the work front opens up.
On the Federal Highway, 211 trees will be removed and 157 new trees planted. On Northbourne Avenue, 444 trees will be cut down, replaced with 671 trees.
English oaks, Quercus robur fastigata, will be planted on the Federal Highway, growing to heights to 17-22m.
On Northbourne Avenue, the government has opted for the native brittle gum, Eucalyptus mannifera, which will grow to 20m, aiming for a higher density "urban meadow".
The natives are to planted in a staggered arrangement of two rows – adjacent to the tracks and the kerb – where possible with a space of 2.5m between the trees and the concrete slab for the tram tracks.
Trees will be spaced 10m apart, with the aim of building a continuous tree canopy.
The works application envisages using tree canopies, foliage and small branches removed from the corridor as compost for new plantings, with the possibility of chipping the logs into mulch for landscaping.
The documents say a photographic archive will be made of Northbourne Avenue from City Hill to Antill and Mouat Street before work begins.
They also envisage the possibility of including heritage and other information on construction hoardings, detailing the history of Northbourne Avenue on hoardings in that section of construction, the heritage values of the Melbourne and Sydney buildings, and of City Hill in their vicinity, and the CSIRO Dickson experiment station in the Swinden Street area.
Stop designs, street furniture and detail of the overhead lines will be part of a separate application.