Work on upgrading Great Yarmouth's tidal flood defences has started at a cost of £40 million.
46 flood defence walls will be improved to protect more than 4,000 homes and businesses.
Great Yarmouth has a history of flooding. During the 1953 east coast tidal surge, the tidal river defences in the town were breached in several places resulting in loss of life.
More recently, in December 2013, approximately 9,000 people were urged to evacuate their homes as a result of the highest ever recorded tide in Great Yarmouth.
The work will see 46 flood defence walls refurbished at locations across the town using an innovative technique that will extend their lifespan by up to 30 years.
Speaking last year when the funding was announced, Sir James Bevan, Chief Executive of the Environment Agency, said: “The upgraded defences will ensure that the flood defences in Great Yarmouth provide the best standard of protection to the local community for many decades to come.”