Work to cut the risk of flooding in the centre of Selby will start in February and last until the end of the year.
The latest phase of the town's £13m flood alleviation project will run from Selby Toll bridge to Bank House farm.
Existing flood banks and walls will be raised and, in some areas, new defences are being built.
Up to 3,000 homes and businesses will benefit from the overall scheme, which began in 2004 and is expected to be completed in 2007.
Selby and nearby areas were badly affected by floods in 2000 when the River Ouse burst its banks.
Environment Agency staff will be at Selby Library on 13 February to answer any questions from the public about the works.