The Transport Agency is fast-tracking the development of an alternative to the State Highway 3 link through the Manawatū Gorge, connecting the Manawatū, Tararua District, Hawke’s Bay and Northern Wairarapa. The Manawatū Gorge is no longer a safe option and has been closed indefinitely. A safe resilient and efficient alternative is required. The Transport Agency is working with key stakeholders and the community identify the preferred corridor before the end of 2017.
State Highway 3 through the Manawatū Gorge has been closed since slips caused major damage to the road on 24 April 2017 following severe weather, and the road remains closed. Continued instability at the Kerry’s Wall site is hampering efforts to make the road safe adding to the complexity of the work.
Geotechnical engineers recently confirmed a large area above the Kerry’s Wall rock face is highly unstable with the entire hillside moving. The rate of movement indicates a slip as large, or larger than, the 2011 slip, which closed the road for 14 months, could come down at any time.
During the weekend of 22–24 July 2017, another slip caused significant damage to the road at the Ashhurst end of the Gorge. As a result the Transport Agency removed all contractors from the current work sites for safety reasons. Those same risks mean the road cannot be safely re-opened for motorists, until the risks are resolved.
State highway traffic is being rerouted across the Saddle Road (north of the Gorge) and the Pahiatua Track (south of the gorge). Given the increased traffic and associated wear and tear on these local roads, the Transport Agency has taken over their maintenance and management since the middle of 2017.
The Transport Agency acknowledges that the increase in traffic over the Saddle Road, particularly in terms of heavy vehciles, is causing disruption to Ashhurst residents. We have resealed Salisbury Road to reduce noise and are currently investigating options for reducing speed through residential areas. The existing situation will remain for the foreseeable future, and the Transport Agency will continue to explore ways to mitigate the strain on the Ashhurst population.
The Transport Agency has received feedback that the closure of the Gorge road has impacted on Woodville businesses. In response, we have undertaken works to try and direct traffic to and from the Saddle Road via Woodville to try and return traffic flows to pre-Gorge closure levels. However, the existing situation will remain for the foreseeable future and the Transport Agency will continue to explore ways to discourage traffic from bypassing Woodville.
The east-west connection between the Manawatū– Whanganui and Hawke’s Bay regions is strategically important. We are committed to carefully considering input from everyone who takes the time to put forward their ideas and feedback.
The community and stakeholders provided extensive feedback on the long list of options, providing valuable input as these options were assessed. A workshop with key stakeholders from local councils, iwi, industry and other interest groups provided further important insights. Now that we have refined the options being taken forward for further consideration, we are again looking for input from the local community and stakeholders which will help us to explore these options in more detail.
Once the community has provided their feedback, all options will be assessed against a range of factors, including: transport performance, cost and constructability, culture and heritage, landscape and visual, social impacts, natural environment and human health. The community’s feedback will also be used to further develop the options and assist us to identify the best option to progress to detailed design. No matter what option is taken forward, the Transport Agency will continue to work with the community to ensure that any transport solution considers matters that are identified as being important to the community, including walking and cycling for example.
The Transport Agency expects to be able to announce its preferred approach by mid-December 2017, with a detailed business case expected to be completed by mid-2018.
No final decision has been made at this stage on the future of the current SH3 route through the gorge. We will continue to monitor the gorge for geological stability. While the current conditions are highly unstable and the road is not a viable long-term state highway option, we cannot categorically rule out the road ever re-opening in some form. Our priority now is moving forward to identify and build a new long-term solution which will be safe, reliable and resilient.
As we are still at the early stages of the options investigation we are not in a position to provide detailed information on the exact routes for each option. More detailed work will be required to understand the impacts of testing changes to gradient and curves and this will likely substantially influence impacts on properties. It is not possible at present to say with certainty how many properties will be affected.
When a preferred approach has been chosen and developed we will have further information on which properties may be affected. We will be contacting property owners as soon as this information is available.
The Transport Agency would complete further route and design work to support a detailed business case. Should this be approved by the NZ Transport Agency Board, the agency would then seek the approvals required under the Resource Management Act 1991 (external link) . At this stage, it is envisaged that those approvals would be sought in 2018/19.
If a property is required for a public work, negotiations for the purchase are conducted by a Land Information New Zealand (LINZ) accredited supplier on behalf of the Crown. The Crown makes acquisitions for the purpose of the NZ Transport Agency requirements.
The land purchase process is set out in the Public Works Act (PWA) and the following is the booklet provided to affected property owners:
Since two large slips closed the road on 24 April 2017, the evening before Anzac Day, the Transport Agency has:
There is a slip known as the ‘Anzac’ slip 6.4km from the Woodville end of the Gorge. Around 10,000m3 material was removed from this site and the road has been repaired.
There is another slip at ‘Kerry’s Wall’ 4.5km from the Ashhurst turnoff on SH3. Around 5,000m3 was removed from this site.
Since Anzac Day, there have been three smaller slips at these same two locations.
Subsequently sometime on the weekend of 23–24 July there was another large slip about 500 metres from the locked gate at the Ashhurst end of the Gorge. Approximately 10,0003 of material, including large boulders, fell on the road.
Approximately 7600 vehicles on average use the Gorge every day when it’s open. Approximately 1100 of these vehicles are trucks.
There are two alternative routes when the Manawatū Gorge is closed. Saddle Road has been the primary alternate route while the Gorge has been closed. The other alternate route is the Pahīatua Track.
Following the 2011 slip the Transport Agency funded a project, which has been managed by the Tararua District Council, to significantly improve the safety and resilience of the Saddle Road. When the last of the works are completed, the Transport Agency will have invested $8.5 million from the National Land Transport Fund into Saddle Road improvements, which is now more resilient and better able to cope with heavy vehicles and freight.
However, the length of the current closure is putting that road under added pressure.
Given the increased traffic and associated wear and tear on Saddle Road, the Transport Agency has taken over maintenance and management of the road from the Tararua District Council so that any repairs and remedial work are managed and funded by the Transport Agency. Contractors began urgent heavy maintenance works on Saddle Road in mid-July 2017, including resurfacing the pavement to improve motorists’ journeys. The Saddle Road upgrade project will continue in summer, to improve the last two sections of the road and ensure they are suitable for the increased traffic volumes. The Transport Agency will also review the Pahīatua Track, with the Tararua District and Palmerston North City Councils.
A safe and reliable road between the Manawatū, Tararua District, Hawke’s Bay and northern Wairarapa is essential for the economic wellbeing of New Zealand and our communities. The Transport Agency is committed to find the best long-term solution that will support economic development and growth for the central and lower North Island through a safe, efficient and resilient state highway network.
In the five years prior to the 24 April 2017 slips, there have been 22 full road closures due to rock falls or slips totalling 338 days since 2007.
The unique geology of the area, in tandem with the nature and location of the road itself, makes the Manawatu Gorge section of State Highway 3 susceptible to slips and rockfalls, resulting in closure of the road.
The cost of remediating the Gorge is in the vicinity of $950,000 (figures as at 27 June 2017).