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Mumbles coastal protection project

We plan to upgrade and refurbish the Mumbles coastal sea defences.

Welsh Government logo.
The aim is to reduce the risk of flooding to homes and businesses that are increasingly threatened by rising sea levels brought about by climate change.

Funding for new defences has been secured from the Welsh Government - and we want the thoughts of the public, business and others to help shape this significant project.


Location and proposed improvements

The work aims to strengthen the defences along around 1km of sea front from close to the Oystermouth Square car park to the Pilot slip.

The existing defences protect nearby homes, businesses and amenities. 

They include sections such as a vertical sea wall and sloping revetment (retaining wall); these support the prom, providing leisure opportunities for pedestrians and cyclists, residents and visitors.

Mumbles coastal protection scheme - promenade (map) (PDF) [4MB]

Mumbles coastal protection scheme - site location / extent (map) (PDF) [4MB]

Due to their age and erosion, the defences have defects. We undertake frequent repairs.

Our new work will repair or replace existing sea defence structures, providing better protection from the sea.

We hope that Mumbles residents, businesses and others can give us their thoughts on the work as it is planned and - in due course - progresses.

Examples of the current sea defences are shown below, clearly showing the poor structural conditions which demands attention.



Video presentation of proposed changes


Project timeline

Project timeline
19th centurySea defences built
20th and 21st centuriesDefences maintained; climate change advances; sea levels rise

Welsh Government launches the Coastal Risk Management Programme; funding to be made available for areas at risk of flooding. 

Swansea Council begins considering how Mumbles could be protected in future.


Outline business case submitted by the council to address long-term flood risk and deteriorating defences.

Council secures Welsh Government support for a scheme estimated to cost around £14m. The council will pay £2m of this, the Welsh Government £12m.


Tests assess condition of seawall structure.  

Public engagement begins to inform Mumbles people of the project progress.


Imperial College London studies Mumbles sea levels and wave activity. Data will help inform design of the new defences.

Council appoints Amey Consulting as design partner; they'll work with the council to fully design the scheme.

Welsh Government launches its National Strategy for Flood and Coastal Erosion Risk Management (FCERM)


Initial plan for scheme delivered to council cabinet members.

Welsh Government announce funding for a number of Swansea schemes, including £495,000 to formulate a full business case and design - and £674,036 to start construction - for the Mumbles scheme, protecting more than 120 properties. Funding also secured for flood risk areas such as Birchgrove, Blackpill, Killay, Llys Dol (Morriston), Gorseinon, Clydach, Cockett, West Cross and Llansamlet.

May - June
Public consultation on sea wall 
Public consultation on future opportunities

June - July
Consultation feedback to council and public

Detailed design process takes place
Planning application process starts with detailed design - including public consultation

Preparatory work due to starts onsite

2022First quarter
Main construction due to starts
2023Construction due to end


Frequently asked questions

Why does Mumbles need an improved sea defence?

We want to protect the Mumbles community and property from flooding to benefit residents, businesses and visitors now and for future generations. Without new sea defences the risk of flooding will just keep on rising. Climate change is making sea levels rise - and that means a greater chance of flooding for some people and businesses based close to Mumbles seafront. We've assessed the condition of existing defences, expected tidal trends, environmental issues and how new defences could be built. We've evaluated a series of options and costs. As a result of that, our suggested approach is to develop a scheme that will significantly reduce to risk of flooding over the next century. 

Who says that parts of Mumbles may flood? Where's the evidence?

It's a fact that sea levels are rising due to climate change. Research undertaken by Arup Consulting on our behalf in 2017 and 2018 provided evidence that a number of Mumbles properties are at risk from flooding due to sea level rises now and over the coming years. The Prom's relatively low, and it's a relatively common occurrence to experience sea water on the footway. During periods of high tides we install "stop logs" across openings in the car park walls that are set back from the sea wall. The average annual cost of this informal secondary flood prevention measure is around £10k. 

Does the seawall really have to be improved?

Yes! Although we carry out ongoing maintenance, the wall's in poor condition due to its age - there are significant cracks and some exposed footings. There's a possibility that it could fail in a major storm. The existing height of the wall is also too low to prevent the anticipated incidents of water coming over the top of the defences due to climate change. A main sewer runs beneath the Prom, retained by the defences; failure of the seawall could harm the natural environment as well as homes and businesses. 

What's at risk exactly? 

Homes, businesses, community facilities, council resources (as we maintain and repair the existing old defences) and tourism income for the area. Despite existing measures, around 79 properties have more than a one in 10 chance of tidal flooding. The ongoing rise in sea levels means this is predicted to increase over the coming decades, with predicted depths and the likelihood of flooding increasing significantly. This would sever vital access to parts of Mumbles and Mumbles Head, including the lifeboat station.

What precise area are we talking about for the work?

The scheme area extends from the slipway on the Swansea side of Verdi's to the Oystermouth Square car park. Mumbles is currently protected by two types of coastal defences; a 0.5km-long mass concrete vertical sea wall that runs from Oystermouth Square to the bowling green area and a 0.7km sloping revetment structure that runs from the bowling green area to near Verdi's. It's our responsibility to maintain and repair them.

And what do you propose to do?

We propose that the project will combine enhanced coastal defences with improvements to the Prom right next to the main seawall. It will support the creation of a sustainable waterfront, provide an asset to the local community and an attraction for visitors. Our proposal is to:

  • bring the Prom up to one level as it currently dips gradually from both ends (Verdis and Oyster Wharf) by up to around half a metre in the middle section
  • strengthen the main structure - this could include a new vertical main wall, new sloping revetment (or a rock structure) to replace the existing sloping revetment - or a mix of those 
  • replace existing railings with a low pedestrian wall similar to that currently at the Oystermouth Square car park; it would be topped with a handrail

The aim is to be sensitive to Mumbles as a seaside visitor destination while protecting people and property.

What improvements could be made as part of work on the wall and promenade?

That's what we'd like the people and businesses of Mumbles to tell us! Apart from providing improved defences to protect the community, the process also offers the opportunity for the public to have their say on matters such as new seating, resurfacing and other environmental improvements. The Prom is popular with visitors and residents but has a restricted width in some areas; our proposed removal of pinch-points could make it safer, more attractive and more accessible for pedestrians and cyclists. Access to the foreshore for pedestrians and boat use is limited to two narrow flights of steep steps and two slipways; we propose to improve access. There's also the chance to suggest ideas for the future look and use of key areas close to the sea wall; matters could include parking, active travel, landscaping, lighting and play.

How have the dimensions been calculated?

To determine the necessary height of the primary defence, modelling has been completed by Imperial College London.

One Mumbles USP is its sea view from the Prom - won't that be affected?

No! Our proposal is that you'll still be able to walk, cycle, play and skate between Knab Rock and the Oystermouth Square car park with panoramic views of Swansea Bay. Yes, we plan to replace railings with walls - but these walls will be of modest height and will protect the people, businesses and facilities at times when flooding could otherwise occur. Our proposal is to have hand rails on the walls.

Will you be building out into the sea?

No. The policy of our Shoreline Management Plan is to "hold the line", that is not extending new infrastructure or development into the sea. This gives the greatest chance of maintain the community and its built and natural assets. Doing nothing is not an option, neither is moving the defence line back - either way there'd be a loss of assets, particularly those behind areas currently protected. If we built into the sea there'd be a loss of beach area and potentially more wave disturbance.

Won't it just mean more concrete in the local environment - a less natural seafront?

It'll mean a safer community - homes, businesses and community facilities protected from the effects of climate change. We want to maintain the attractiveness of Mumbles as a visitor destination and as a place to live and do business - so we're working hard with others to deliver the best option. Options for additional greening of the prom are be considered as part of the proposals.

During the work won't this mean lots of upheaval for the community?

Like any major construction project there'll be trucks and other plant on site. Our consultants, Amey, are experienced in this type of work and know they must be considerate to people living in Mumbles, visiting and working there. Work on the prom will take place in a phase manner - extensive stretches of the Prom will remain open at any one time. They are working with a South Wales contractor to ensure the development of any selected option will have the least impact to Mumbles and the surrounding area. They want to do a good job and want the community to feel optimistic about it and reassured that this is a plan for the long-term success of Mumbles.

Who's decided on the seawall options?

The cross-section of the wall is still to be determined. The project team - managed by officers from our highways and transportation team - are looking at options, taking into account considerations such as cost, the practicality of building work, visual impact, the environment and other key aspects. Their considerations will help determine the preferred solution. We consulted with the public in 2019. The responses indicated a wish for careful consideration of a number of key points, including the new scheme's visual impact and the effect of the work on the community. These have been considered in our subsequent work which has seen us and our consultants Amey work towards a scheme that we're now showing to the public and other important stakeholders. We thank all those who had their say in 2019 - but please continue to let us know what you think by taking part in the latest consultation! We greatly value your input.

Who'll decide on the final scheme?

Following ongoing work, options will be presented to the council's cabinet to make the final decision. The public and other key stakeholders have a significant opportunity to influence the scheme with the consultation being held now and, in due course, with the formal planning process. Those being kept up to speed and being asked to comment include: Central Government and Welsh Government, council members, Mumbles Community Council, the public, Mumbles residents, local landowners, local businesses, Natural Resources Wales and others. Please spread the word so that all those with an interest can have their say. 

Won't all this have a knock-on effect for parking?

No sea defence plans have been approved. However, we would like to know how you think parking in the area could be upgraded or improved.  

What'll happen to the boats that park on the Prom?

No sea defence plans have been approved yet. However, we're interested in what you think about the boats. Tell us your views about them and we'll take them on board as the project proceeds.

Will the Prom stay the same width?

No sea defence plans have been approved yet. However, we'd be interested to hear your thoughts on a consistent width so that everybody can use the Prom; this includes families with children who want to play, cyclists and those with mobility issues. We're interested in what you think so please tell us your views.

Do you intend to change the area around Hennebont Gardens?

We propose that a green area will remain here. We're eager to hear your thoughts on this area along with other parts of the Prom.

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