The £31M plan to realign the A59 away from the landslip-prone section at Kex Gill has been adopted by North Yorkshire County Council’s executive.
The route of the planned realignment, which was developed by WSP, was approved by the executive and involves construction of 5.4km of new carriageway to the north of the existing A59.
During the meeting, members of the executive were told that the risk of further landslips at the site made it essential to press ahead with the scheme.
Ground movement in May this year closed the route for over a month and is still subject to traffic restrictions and monitoring currently being undertaken by Capita shows that there is ongoing instability. The road was also closed in January 2016 because of ground movement.
The council has estimated that it has invested around £1.6M on remediation and repair work at Kex Gill over the last decade.
WSP summarised recent data from Capita and told the council that “the landslip system is of such size and complexity as to render all remedial options as practicable only in the short and medium term, and all long term remedial options are considered non-viable due to the complexity and scale of the engineering solutions required and the resultant inhibitive cost”.
Council executive member for open to business Andrew Lee said: “The only solution to keep this road open and safe is to realign the carriageway.”
In its report, WSP said: “The diversion removes the risk of landslips to the southern slope impacting on the A59 and, in comparison to the scale of works and required maintenance/inspections programme that would be required on the southern slope, results in less significant impact on the natural heritage of the site”.
Public consultations for the realignment were said to have shown strong local support for the realignment work as closures have a significant impact on other roads with the A59 being the only major trans-Pennine route between the A66 at Scotch Corner and M62.
Lee said that developing the new route had been challenging due to the environmental setting of Kex Gill and the environmental importance of the area surrounding the site.
“We think that the route we have set out is the best and will provide a long-term solution for the A59,” he said.
Environmental studies for the route will now be commissioned and the council hopes to submit a planning application for the scheme by autumn next year with a view to completing the work by summer 2021.
Department for Transport identified the realignment for delivery under an accelerated delivery programme in early 2017 in order to align with funding opportunities. This accelerated delivery means that the development window has been reduced from six years to three, which the council described as “an exceptionally challenging timescale” that will mean some delivery phases will be run concurrently rather than consecutively.