Bat colonies of 'potentially international importance' have been found close to the route of the controversial Norwich Northern Distributor Road, which means special gantries, bridges and an underpass will have to be built to stop them being hit by traffic.

Norwich Evening News: The Great Crested Newt, which campaigners say they have discovered close to the site where a lorry park is plannedThe Great Crested Newt, which campaigners say they have discovered close to the site where a lorry park is planned (Image: Archant)

And it has also emerged that the building of the £148.5m road will mean that great crested newts – a species protected by UK law – will have to be moved from a pond on the route.

Norfolk County Council wants to build the 19.5km dual carriageway road, from the A47 at Postwick to the east of the city to the A1067 Fakenham Road to the northwest.

The government has agreed to contribute £86.5m towards the cost and has said the scheme is of 'national significance', which has fast-tracked it through the planning system.

That means the Planning Inspectorate will, this summer, weigh up evidence before making a recommendation on whether to grant a development consent order.

But a study of the wildlife that will be affected by the road, during its construction and once it is up and running, has revealed that if it does get the go-ahead special measures will need to be taken to protect species.

An environmental statement put together by the county council has shown that there are 10 bat species within what is known as the road's zone of influence.

Hundreds of bats have been trapped since 2009, with a number of them tagged and radio tracked to establish the routes they fly, which in some cases stretched to distances several kilometres away.

The checks led to the identification of colonies of Barbastelle bats, described in a report by council officers as being 'of national, or possibly international importance', at Weston Park, near Lenwade.

Seven tree roosts and three building roosts of bats are due to be removed and the county council plans to install new bat houses and bat boxes.

But council officers also acknowledge the road could cut off flight routes. Officers state: 'To mitigate for these potential impacts, a combination of wire bat gantries and green bridges would be provided, which would promote the continued use of the identified major flight routes that would be severed by the proposed scheme.'

The use of gantries - wire mesh structures which try to force the bats to fly higher than traffic - would be controversial. A 2012 study carried out by Leeds University showed bats continued to use their former routes, although the county council says the gantries it proposes differ from the ones investigated in the study.

Green bridges - bridges over roads covered with hedgerows to encourage safe crossing points for bats - are proposed for Marriott's Way and Middle Lane, while a bat underpass is proposed at the Rackheath Estate.

But bats are not the only species the road would affect. Studies found great crested newts living in the construction zone. These amphibians are protected by UK law and, during construction of the road, fences will have to put up around their ponds to protect them.

However, at Rackheath a pond and nearby habitat will have to be removed. The newts will have to be trapped and moved to newly created ponds.

The council would have to secure a European Protected Species mitigation licence to do that, as it is against the law to destroy habitats of great crested newts.

And the road would also lead to the loss of foraging habitat and nesting sites of a barn owl population. Officers would look to put in new boxes and create habitats for the reptiles and small mammals the owls feed on.

According to a draft local impact report, which will be discussed at Broadland District Council's cabinet meeting on Thursday, the impact of the development on bats, great crested newts and owls, plus on breeding birds, reptiles, hares, otters and badgers, could be 'offset' using £100,000.

The county council says the road will bring a huge economic boost and connected improvements, such as a rapid bus transit in Norwich.

But critics say it will lead to more traffic and say the homes which will spring up around it will concrete over swathes of the countryside.

• What do you think of the plans for the road? Write, giving full contact details, to Letters Editor, Prospect House, Rouen Road, Norwich NR1 1RE or email eveningnewsletters@archant.co.uk.