Environmental enhancements for ALPURT B2
Friday 6 August 2004
Transit announces major environmental enhancements for ALPURT B2 – Nukumea eco-viaduct and Johnson’s Hill tunnel
Transit New Zealand today announced that following months of thorough investigation, the Transit Board has agreed to include two further environmental enhancements within the scope of the ALPURT B2 toll road project. These are a second eco-viaduct over the Nukumea Stream, to protect an ecologically sensitive area, and a tunnel through Johnson’s Hill, reducing the visual and ecological impact of the new road, and improving its alignment and safety.
“A key benefit of toll roads is that they provide a mechanism for achieving the greater mitigation of the environmental effects of construction expected of us since the passing of the Land Transport Management Act last year, and a higher level of service, including improvements to grades and alignments,” says Rick van Barneveld, Transit CEO.
“The decision to include the Nukumea eco-viaduct and Johnson’s Hill Tunnel demonstrates Transit’s commitment to pursuing additional environmental enhancements over and above the environmental standards previously approved for this road, which will help to realise the sustainability aims of the Land Transport Management Act 2003.”
The Nukumea eco-viaduct is a 210-metre viaduct across the south tributary of Nukumea Stream in RAP 21 (Recommended Area for Protection), which will leave the stream intact and provide considerably enhanced connectivity between two ecologically significant areas.
Transit has been investigating the option of a tunnel through Johnson’s Hill for some time. A number of significant, complex issues impacting on the feasibility of this option needed to be worked through before the expectations of those who have sought this so keenly could be raised and a firm commitment could be made.
As a result of this investigation, Transit has revised the project scope to include twin tunnels through Johnson’s Hill before a junction with the existing route south of Titford’s Bridge. Completion of four lanes across the Waiwera Estuary is now possible because the tunnel design allows for a simple northern connection to the existing two-lane highway. That new connection can also accommodate the lane reduction that previously had to be located on the south side of the estuary.
“This modern 21st Century tunnel will be a first for Transit,” says Mr van Barneveld. “The Northern Gateway Alliance delivering ALPURT B2 has a specialised tunnel team in place with international experience, and one of New Zealand’s most experienced tunnelling practitioners on the independent expert team.”
Transit had previously rejected the idea of a tunnel through Johnson’s Hill on the grounds of cost and safety. However, advances in tunnel technology and construction techniques, together with the greater flexibility tolling allows to enhance environmental outcomes, now makes this a viable solution.
These enhancements are in addition to a range of other initiatives already included as part of the Environment Management Plan for ALPURT B2. The plan includes fish culverts, extensive revegetation, and the Otanerua eco-Viaduct, which like the Nukumea will enable regionally endangered fern birds to move safely underneath the motorway.
“Transit takes its environmental responsibilities very seriously. We continue to investigate and consider a number of options to ensure ALPURT B2 will best meet the Land Transport Management Act’s environmental sustainability and safety criteria,” says Mr van Barneveld.
The Nukumea eco-viaduct and Johnson’s Hill Tunnel are not expected to add any time delay to the duration of ALPURT B2’s construction. Total project cost for the completion of ALPURT B2, including the environmental enhancements, is estimated at $300 million.
Subject to funding approval from Transfund in September and securing approval to toll from the Minister of Transport, a start on construction this summer is still Transit’s target.
Transit has proposed a $1.80 toll tariff on ALPURT B2 (CPI indexed to opening day), which would optimise overall use of the network – including the toll road and the alternative routes – while still ensuring that the project is financially viable.