Plans for a 500-metre long flood wall along Rochdale Road have been submitted to Calderdale Council.
The application by the Environment Agency is the delayed third phase of the Todmorden flood defence scheme, which will help to reduce the risk of flooding to 658 homes and businesses from Walsden Water.
Subject to planning permission being granted, construction work will begin in the summer.
The flood wall, between Shade School and Morrisons supermarket, will be built in sections and will vary between 1.2 and 2.8 metres in height.
It will be made of concrete with natural stone cladding so it blends into the local environment.
In addition to the new wall, sections of culvert which take Walsden Water under Todmorden town centre will be strengthened as part of the project.
Most of this work will be carried out from within the culverts to minimise disruption to the Market Hall.
Environment Agency project manager Will Benedikz said: “While there will inevitably be some disruption during construction, it will be kept to a minimum and will result in long term benefits for the whole town as the risks and effects of flooding are significantly reduced.
“We will work with businesses, the local authority and local people to make sure that all practical steps that can be taken to minimise disruption are taken.”
The 18-month construction programme will take account of seasonal business peaks so work will be tailored to ensure that there is minimal disruption over the busy Christmas and Easter periods.
The Environment Agency plans to open a compound in Salford Way, which will include an information room for people to visit if they want to raise issues of concern or check on progress, and establish a stakeholder working group, reflecting a wide range of the town’s interests, with which it would work in partnership during the construction programme.