Anglian Water started building its 2.2km sewer pipeline in Norfolk alongside the A148/A47 last month, as part of plans to improve the resilience of the sewer network in the area, the company said in a statement.
But during survey work in Kings Lynn, ecologists discovered the commophila aeneana moth, known as the orange conch, was present at a location along the route. The orange conch was thought to be extinct in Norfolk.
As a result, Anglian Water says it will shift the pipeline by 485 metres around and underneath the moth's habitat to avoid disturbing them.
The water firm has also proposed construction exclusion zones and bringing on board an onsite ecological clerk of works to oversee the scheme’s operations.
The larvae of the orange conch live in the roots of ragwort, Jacobaea vulgaris, so the ecologists at the company also decided to change the method of the pipe’s construction to a directional drilling technique, which involves no digging, to further minimise the impact on the species.
Where ragwort needs to be removed, it will be watered and replaced upon completion, with follow up checks in the year, the company said.
Anglian Water spokesperson, David Hartley, said: “We take our role in the environment very seriously, and although we are investing millions of pounds into area, it’s imperative that we do so with the environment in mind. We’re really pleased that this vital work will help to improve the existing sewer network, ensuring a more resilient wastewater network in the area.”
The new pipe will replace an existing sewer pipe that has reached the end of its optimal operational life, helping to reduce the likelihood of flooding and pollution in the area, the company said.
The scheme is expected to be completed by April 2020.