A £115m plan to protect Weymouth from tidal flooding and erosion over the next 100 years has been unveiled, including building up and strengthening kilometres of harbour walls and sea defences.

Work will start this year on the first phase of the huge project.

An ambitious and far-reaching strategy has been drawn up detailing how authorities plan to defend the town from coastal flooding and erosion through an extensive programme of building up the harbour walls and Esplanade sea defences.

The area around the harbour is blighted by flooding when high tides combine with severe weather. But Dorset Council says this problem will get a lot worse with a predicted sea level rise of up to 1.3m over the next 100 years and more intense weather events as a result of climate change.

It is warned that without investment in managing this risk, Weymouth faces 'increasing direct losses through flooded assets and infrastructure and indirect impacts such as a failing property market due to blight and increasing social deprivation'.

The council has published the Weymouth Harbour & Esplanade Flood and Coastal Risk Management Strategy which brings together findings and recommendations from numerous studies undertaken by both the council and the Environment Agency.

The preferred approach outlined in the strategy is a comprehensive programme of wall replacement and wall raising around the quay and on the seafront. This will both reduce flood risk and replace deteriorating walls, some of which are already at the end of their design life.

The report, which can be viewed on the council website and will go before Dorset Council's Cabinet for approval on October 6, says the huge scale of engineering works will require investment in excess of £115 million from multiple sources. Around a quarter of this would be funded by Dorset Council and agreed as projects come forward for approval.

The overall cost would be pushed up to £141 million if the option of building a tidal barrier across the harbour (Custom House Quay to Nothe Parade) from 2070.

Cllr Tony Ferrari, Dorset Council’s Portfolio Holder for Economic Growth, Assets and Property, said: “This is a hugely exciting and ambitious strategy that deals with the effects of climate change and helps protect the future of Weymouth. It will see record amounts of investment in coastline defences and I strongly encourage everyone to read the document so they can see what is planned.

Cllr Ferrari said the next step was to get everything in place to govern and manage the various projects proposed and continue to work closely with the Environment Agency to secure funding.

He added: "I’d like to thank the many agencies that have been involved in the studies that helped us devise this strategy that, when implemented, will cement Weymouth’s reputation as a safe and attractive place to work and visit.”

Work programme

Phase one of work starts this year and covers three areas of work:

Harbour sea defence walls – 2020 to 2030

Replace seven sections of harbour walls (eg. North Quay, Custom House Quay, Westwey Road) and raise nine sections (eg .Commercial Rd, Cove Row, Nothe Parade).

Esplanade sea defence – 2020 to 2035

Repair the Greenhill section sea wall foundation (2020-2025). This will be followed by improvement works to the Greenhill section sea wall with associated promenade works (2034-2035).

Harbour walls (general) – 2020 to 2027

Replace four sections of peninsula walls between 2020-2027.