Mumbles Coastal Protection Scheme

LOCATION:

Near Swansea, West Glamorgan

Coasts & Ports

This £23m project comprised coastal protection works along Mumbles Promenade. The improvement works provide enhanced flood and coastal erosion protection to businesses and residential properties previously at long-term risk of flooding.

Our collaborative involvement with the scheme began at ECI stage when we were invited to provide budget, buildability and logistics advice for each design option. We proposed a methodology and plant schedule to support the Marine Consent Licence application.

Mumbles was previously protected by two types of coastal defences – a 0.5km mass concrete vertical sea wall and a 0.7km sloping revetment structure. Some of these defences were built over a century ago.

Our works comprised:

Construction of a concrete faced, concrete stepped apron and sheet pile toe wall. This extends 4.5m to 5m forward of the existing wall. The stepped revetment is installed to a depth of 1m. A steel sheet pile toe has been installed. The wall has been faced with specially designed panels to enhance biodiversity.
Construction of a new concrete revetment. The slope and alignment matched the existing but the footprint extends further onto the foreshore.
Raising of the promenade structure up to around 0.5m in the middle section, where is previously dipped from either end. The promenade has also been widened to create a segregated pedestrian footpath and cycleway.
Public realm improvements including seating, views and connectivity, with enhanced hard and soft landscaping.

Challenges

The works took place in a busy, high-profile area, attracting significant public interest.

Adjacent to Blackpill SSSI, designated for its importance as a habitat for local and migratory birds.

Name Surname
Job role on project

Solutions

We held face-to-face meetings with residents and businesses to inform them about the project’s progress and address concerns. We have taken a proactive and collaborative approach to engaging with the community including:

Working with Swansea Council’s Beyond Bricks and Mortar scheme to provide trainee/apprentice placements.
Developing our approach from our previous project at Sandy Bay, we worked with the council, local schools, community groups and a multimedia company to produce the ‘Mumbles Sea Through Time’ educational programme.
Held a ‘Meet the Buyer’ event to engage with local suppliers.

The key risk was pollution to the foreshore, so we developed pollution prevention plans including emergency response. All plant used biodegradable oil. Weepholes in the original sea wall were checked for the presence of birds prior to works commencing. Any at risk of becoming inhabited were filled or covered.

During the ECI stage we collaborated with Swansea University’s Sea-Hive project to trial a variety of hexagonal tiles to determine the design that best supported biodiversity. We installed thirteen different tiles on the sea wall, with the university monitoring the marine species that populated each one. The most effective pattern was selected and installed on the new sea wall.