Critical infrastructure like roads and train stations could be affected by higher tides and stronger storms and the city’s transport network could be severed by flooding, according to previous council reports.
The primary threat is from tidal flooding, expected to grow as polar ice sheets melt.
The plans include building nine miles of flood defences along the Avon from Swineford to the east of Bristol, through the city centre and up to Shirehampton.
The council is working with the Environment Agency and the West of England Combined Authority to get them built.
Construction was initially expected to begin next year, but now won’t start until the next decade.
Brown added: “We are now in contract with Jacobs and work has been progressing well in mobilising the new team and facilitating a smooth transition from the previous phase of the project.
“Our current programme shows an earliest possible construction start in 2030/31, while opportunities for quick wins and third party delivery opportunities will be continually explored.”