Work is now well under way on the £1.3 million culvert improvement scheme in Shepton Mallet in an attempt to solve the town's past serious flooding problems.

Contractors Team Van Oord started work on the huge project last month, operating from their base at the telephone exchange.

Lower Lane is now closed for up to 10 weeks. But Environment Agency spokesman Nigel Bennetts said motorists seemed to be coping well with the diversions and praised drivers and residents for their support and co-operation. Regular public meetings are being held to keep people up to date with progress.

The contractors carried out exploratory work with trial holes and CCTV cameras to pinpoint exactly what they would be encountering before excavation started in earnest in what is one of the most important historic parts of the town.

Archaeological trial trenches revealed the original floor surface of the 18th century blacksmith's mill building and infilled arches in the wall which may have held the mechanism of the waterwheel which originally powered the mill.

Mr Bennetts said it was still too early to date the works. As part of these remains are being removed for the culvert improvement works, it has been agreed with the county council's archaeology service that these sections are being excavated fully by the archaeologists to provide a record of the development of the mill on the site.

Mr Bennetts said the improvements works were all going to plan. "We have not found any Roman Villas or any amulets yet – but we live in hope! We don't know what we might find."

The improvement scheme includes the construction of a special bypass culvert to increase the water flow capacity of the drainage system in the town to prevent the floods that have devastated parts of the town in recent years.

The project has been approved by the Wessex Regional Flood Defence Committee and funded through the Local Levy and the work is expected to be finished by Christmas.