About 15,000 homes near the River Thames could be protected from flooding by 2027 after a flood defence scheme was given a £270m funding boost.
The scheme will protect homes and businesses between Datchet, Berkshire, through Surrey to Teddington.
The Environment Agency said it could now afford to build the defences thanks to funding from Surrey County Council.
In 2014, about 2,000 people were flooded out of their homes in Chertsey, Egham, Sunbury, Staines and Weybridge.
Central government, local authorities and other partners including Thames Water will all contribute to the scheme.
Dave Bedlington, from the Environment Agency, said the new funding from Surrey County Council meant the scheme could now be shown to be affordable.
If the defences were not built, flooding such as that seen in 2014 would become more frequent, according to Mr Bedlington.
"If everything goes with a fair wind we'd being submitting our planning application in two years' time. Because of the scale, that's likely to take a two-year inquiry," he said.
If given the go-ahead, construction could start in 2023 and it could be operational in 2027, he added.
The Environment Agency said three new channels alongside the River Thames would reduce the flood risk at Datchet, Wraysbury, Egham, Staines, Chertsey, Shepperton, Weybridge, Sunbury, Moseley, Thames Ditton, Kingston and Teddington, affecting 15,000 homes and 2,400 businesses.
The plans also include 260 acres (106 hectares) of new public open space and the creation of 615 acres (250 hectares) of new wildlife habitat, a spokesman said.
Tim Oliver, leader of Surrey County Council, said: "The floods in 2014 were devastating and ever since then it's been clear we need to do all we can to make sure our residents and their properties are protected from such risks in the future."