Somerset County Council pledged this week to clear dead trees and dredge streams near the Blackbird Bends, which are often under water.
Phil Anderson, landlord of the Blackbird Inn, said: “Apart from the delays to traffic while the work is being carried out it can only be a good thing.
“People know it floods here and avoid it when it’s been raining heavily, so if they can stop that it will be a benefit to us.
“Trade has been hit big time in the past when the road has been closed. If the road is closed there is no business.”
The council will remove silt, re-align the streams and lower rocks to funnel water out towards the River Tone.
Work started on Monday and highways teams removed dead and dying trees from the site to allow machinery to move in.
The work is expected to take two weeks and the A38 will remain open, although temporary traffic lights might be needed during some stages.
“Our aim is to protect the road and bridge at Blackbird Bends, which have been vulnerable to flooding during times of heavy rainfall.
“The streams and drains will be able to handle much more water after we’ve finished and will help to reduce the risk of flooding.”