A multi-million pound scheme to revamp one of the busiest junctions in Norfolk will only be able to take place after water voles are moved, highways bosses have revealed.
The Thickthorn junction, on the edge of Norwich, is due to be changed as part of the £300m scheme for the A47 between Peterborough and Great Yarmouth.
But the changes involve diverting a stream near Hethersett, which is a habitat for water voles - a species which is protected by law under the Wildlife and Countryside Act 1981.
Peter Havlicek, the A47 programme manager, revealed the presence of the voles when he gave county councillors an update on the scheme at a recent meeting.
He said: “The interesting thing with this scheme, on the ecological front, is that we have got the presence of water voles.
“With the diversion of the Cantley Lane stream, where the Cantley Lane link joins in with Cantley Lane, we’ve got to make sure that these water voles are moved south of the Cantley Lane link and there is licensed work we will need to do to make sure.”
When asked how many water voles are at the location and where they would be moved to, Highways England said: “All the ecology surveys need to be complete before we are in a position to determine the number of water voles and also suitable receptor sites for the translocation of the water voles.
“Identification and enhancement of the receptor sites to provide local conservation benefit will be determined through engagement with Natural England.
“It will also be necessary to apply to Natural England for a protected species licence in order to undertake any conservation work relating to the water voles prior to any construction works taking place.”
Norfolk County Council will also need to give consent before the section of the Cantley Stream can be diverted.
The Norfolk Wildlife Trust said it would be looking closely at the situation, with water voles having faced serious decline across the country in recent years.
Mike Jones, conservation officer at the trust, said: “We are aware of the potential impacts of the Thickthorn proposals but are waiting to see the full results of the surveys in the application, which we understand will be made early next year.
“Water voles have faced serious declines across the whole country over the last few decades and it is vital that these works ensure the local water vole population and their habitat is secured and enhanced.”
The proposed changes at Thickthorn include two new bridges and an underpass allowing motorists to get from the A11 onto the A47 at Thickthorn without using the roundabout.Tproposals include a new slip road off the A11 northbound, before the roundabout, which will take motorists beneath both roads before rejoining traffic on the A47 heading towards Great Yarmouth.
The complete overhaul of the roundabout will also see a segregated left-hand turn added to those travelling eastbound on the A47, a new footbridge added and a fourth lane on the southern part of the junction.
Further proposed changes to the junction, which is used by 53,000 motorists a day, include new traffic lights on the B1172 arm of the roundabout and a new bridge connecting Cantley Road South with the Norwich Road.
An application to get a development consent order for the Thickthorn work is due to be lodged in March next year, with Highways England saying that, if consent is granted, work could start in 2023, with the new junction open in 2024.
Given how busy the junction is, Highways England has been considering how to minimise the disruption when the work is done.
One possibility being explored is whether the underpass can be installed in the form of a box slide, so the already constructed underpass is slid into position after as a section of the road it will go under is dug up.
That could mean that work can be completed in the space of a long weekend, rather than 14 months of contraflows, lane closures, speed limit reductions and overnight closures.
The overall cost of the Thickthorn changes, which are opposed by the Norwich Green Party as taking Norfolk in the “wrong direction on climate change”, has not yet been confirmed.
Highways England revealed last week that the dualling of the A47 Acle Straight has not been included on the next tranche of government schemes.The road had not been included in the government’s road investment strategy for 2020-25, but campaigners had hoped it would be included in the next phase for schemes from 2025 to 2030.
But it was not, so the next chance of getting into the government’s thinking is not until 2030 to 2040.
Roads versus wildlife
The water voles at Thickthorn are the latest example of where the drive to build new roads comes into conflict with wildlife.
The proposal that the voles are relocated somewhat mirrors the case of the Acle Straight.
The dykes there are among few habitats of the Little Whirlpool Ramshorn Snail.
Those tiny snails are on an international ‘red list’ of endangered species and, like the water voles, protected.
Highways England has moved hundreds of the snails.
Studies show they survived the switch and are breeding, although there are still three more years before final conclusions can be drawn.
When the Norwich Northern Distributor Road was built, 12 bat crossing bridges were built. But ecologists said they were not working and rare bat roosts had been driven away because of the road.
Norfolk Wildlife Trust has raised concerns the Western Link will destroy habitats, including for barbastelle bats.
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