Feedback and Response

The risks associated with the rock armour during construction, operation and maintenance are assessed in line with all project risks in accordance with relevant legislation and best practice including a designer risk assessment. The residual risk of entrapment in rock amour is known, and further detail are below.

Construction of the defences, of which the rock armour is an integral part, will considerably reduce the risk to life on the promenade and in Barmouth itself from flooding.

• The chosen option was considered as a balance of performance, operational safety, environmental and visual impacts through a detailed and robust assessment process, outlined in the OBC approved by Welsh Government in 2021. Other options included and appraised were beach recharge, offshore breakwaters and managed realignment.
• Once chosen, the safety of the proposed option has been maximised by:
  • Ensuring the stability of the rock armour through design and testing with physical modelling, for its design life.
  • Improving accessibility to the beach via new stairs and improved northern ramp, meaning there is no need or encouragement for people to climb on rock armour for access even in busy times.
  • The provision of a sloped upstand and handrail to prevent access from the steps and ramps to the rock armour.
  • Warning signage at regular intervals and access points to the beach
  • Improving access to the existing revetment with a concrete walkway and removal of the existing concrete buttresses, which will include an upstand between the slab and the rock armour
  • Provision of new life-rings and / or throw ropes
  • Improving accessibility to the promenade itself
  • The rock armour will not require regular maintenance. If significant movement occurs after a storm event, this would be managed by the Council.
  • The design has been discussed with HM Coastguard and Harbour Authority, and we will continue to liaise with them, particularly regarding safety equipment and signage, as the design and construction progresses.

The height and extent of the wall and rock armour have been minimised as far as possible while providing protection to Barmouth for the next 50 years. The materials and finishes have been chosen to be sympathetic to the existing environment and to be able to withstand the coastal environment.  

Landscape and seascape impacts have been assessed as part of the Environmental Statement (ES). The visual effects will become more integrated into the landscape. Weathering of materials and maturation of vegetation will contribute to a softened appearance, reducing the perceived dominance of the new coastal infrastructure. While permanent changes such as the removal of groyne sections and the presence of the rock revetment and sea walls remain visible, they are less intrusive and more in keeping with the coastal character.

Tourism impacts during construction will be minimised by not carrying out works during the summer holidays. On completion of the works, the promenade and beach, particularly to the North, will be more accessible (including to those with limited mobility) and parking and active travel will be improved. The removal of groynes will make it easier to move along the beach itself. These improvements are expected (and have been assessed in the ES) to improve tourism in Barmouth through better beach access and improved public amenities along the northern promenade.

The existing groynes on the beach are known to be in poor condition. Movement of beach material via wave action (longshore drift) is minimal at this location in Barmouth, and therefore the groynes (even if refurbished) would not provide significant performance benefits to the town for existing and future storm events. At OBC, beach recharge was considered as part of the scheme, which would require beach levels to be considerably higher than they are now (at least level with the primary wall) and the beach material to be shingle sized, similar to the bank North of the promenade.

Groynes also reduce the amenity value of the beach and ability to traverse it from north to south and vice versa. Some wind-blown transport of beach material does occur but is not generally affected by the groynes.

The groynes have been shown through modelling and analysis of historical performance, not to retain beach levels at the Northen promenade even when intact. 

The risk of flooding has been determined using the latest industry best-practice guidance which dictates that sea level rise, storms, and rainfall events all need to be assessed in combination. This shows a considerable risk of flooding to Barmouth now and in the future. A storm with a 2% chance of occurring now could lead to flooding of over 2m in some parts of Barmouth. By 2125, the same risk is expected with a flood that has more than a 50% chance of occurring.

Repairing or upgrading the existing flood defences (for instance the wall on the landside of Marine Parade) would help in some flood events, reducing the chance of breaches through structural collapse. However, many flood events would still overtop this wall, leading to flooding which can cause loss of life and damage to vehicles, infrastructure and property. Welsh Government guidance and funding for flood risk schemes require detailed optioneering, assessments and a standard of protection to be achieved against major flood events for both current day events and taking into account climate change guidance data. Without taking account of these key elements funding would not be made available for a flood risk scheme.  We are taking action now to reduce the growing flood risk to Barmouth.

The height of the wall has been modelled to be as low as possible while providing the necessary protection. Much of the early modelling was carried out numerically (using computer simulations), combining tidal overtopping, rainfall and surface water flows to map the flood risk at OBC stage. The preferred option was also modelled physically, using a scale model of the defences and promenade to verify the extent of coastal overtopping in a range of storm events.

Through the development of the project, several alternative options were considered for enhancing the coastal sea defence. The following options were considered, but discounted (list not exhaustive full appraisal is included within the approved Outline Business Case):

• Do nothing – This was considered as a baseline to compare with the other options
• Beach reprofiling and recharge – Instead of Rock Armour, the beach level was considered to be increased to improve protection, with heavier material like cobbles. This was discounted on the basis of defence performance, cost and environmental and amenity impact.
• Managed realignment – This involves defences being brought landward and naturalising the coastline. However, this would likely lead to loss of land, property or infrastructure and so was not considered further.
• Offshore defence- an offshore reef or breakwater was considered. This would require very large amounts of rock material being deposited on the beach relatively close to the promenade in order to be effective, severely impacting on views and the beach’s amenity value as well as presenting safety and navigational risks (by creating a new offshore structure close to the shore) and significant impacts on the sensitive offshore habitats. It is also anticipated to be very high cost.
• Groynes – the existing performance of the groynes was carefully considered. From a review of the local coastal processes including historical information, it was determined that there is very little movement of material along the beach (longshore drift) in the location of the promenade. Generally, lowering of the beach has been due to wave reflection from the existing concrete promenade.

Improving accessibility has been at the heart of the design of the scheme.

From the promenade to the beach, we will provide six new sets of steps to replace the existing, broken and degraded ones. In addition, the ramp by the North car park will be extended in line with the latest accessibility standards. There will also be a new concrete landing between the rock armour and the primary wall which will be available for people to walk and relax on.

On the promenade, the crossing points will be improved to make them much safer for pedestrians, and to include planters to improve the area’s look and feel. More drop kerbs, cycle parking, seating and wayfinding signage will increase accessibility too.

The construction of the defences will mean that existing stoplogs that cross road junctions over winter will not be required. The new flood gates will only require closure in large storms, and in that case for less than a day at a time. Even when these are closed, the area landside of the new wall will be available from other road routes.

Following Welsh Government’s Flood and Coastal Erosion Risk Management (FCERM) Business Case Guidance (BCG) the OBC was undertaken; a Longlist of nine options (and sub-options) were identified and then screened against the investment objectives, and assessed in line with the following criteria: constructability, cost & performance, environmental impact and applicability. Each of the shortlisted options were assessed against the Engineering performance, Sustainability and well-being performance, their Economic performance and their Financial performance.

What other options did we consider?

Through the development of the project, several alternative options were considered for enhancing the coastal sea defence. The following options were considered, but discounted (list not exhaustive):

Do nothing – this was considered as a baseline to compare with the other options

Beach reprofiling and recharge – instead of Rock Armour, the beach level was considered to be increased to improve protection, with heavier material like cobbles. This was discounted on the basis of defence performance, cost and environmental and amenity impact.

Managed realignment – This involves defences being brought landward and naturalising the coastline. However, this would likely lead to loss of land, property or infrastructure and so was not considered further.

Offshore defence – an offshore reef or breakwater was considered. This would require very large amounts of rock material being deposited on the beach relatively close to the promenade in order to be effective, severely impacting on views and the beach’s amenity value as well as presenting safety and navigational risks (by creating a new offshore structure close to the shore) and significant impacts on the sensitive offshore habitats. It is also anticipated to be very high cost.

Groynes – the existing performance of the groynes was carefully considered. From a review of the local coastal processes including historical information, it was determined that there is very little movement of material along the beach (longshore drift) in the location of the promenade. Generally, lowering of the beach has been due to wave reflection from the existing concrete promenade. Therefore, the cost of refurbishing the groynes outweighed the benefit they provide.

Increasing the Primary Wall height (the existing wave return wall) to achieve the desired standard of protection would result in needing to significantly raise the wall to a height greater than the current proposed back wall. This is due to the elevation difference between the current front and back walls, and the increased wave height that the front wall would experience. This would cause a similar visual impact to the adjacent houses, but would also mean a loss of sea views for promenade users.   

A significant amount of work and development has been undertaken over the last year as part of the FBC stage to understand the problem and to shape the solution. We have worked closely with our Contractor and Designer to carefully consider the functionality of the defence, the cost of the proposals and how people would use the promenade.

Extensive modelling, both digital and physical, has been undertaken to help determine the key parameters of the defence:

• The digital modelling uses industry standard computer models and practices to determine the impact of different flood events, whilst considering the impact of rainfall for a variety of different scenarios.
• The physical modelling involved building a scale model of the sea defence in a water flume and testing different storm events to understand how the sea defence performs. Amendments were made to the model to optimise the defence.

This modelling has helped define: the total length of the defence and how far south towards Barmouth it needs to extend; how high the Secondary Wall needs to be; the size/placement of Rock Armour; and the need for flood gates.

We have undertaken extensive stakeholder engagement with interest parties (both statutory and non-statutory) including Natural Resources Wales, Natural England, emergency services (including coastguard), Cyngor Gwynedd, community and town councils and the public.

We have undertaken environmental surveys to understand the species and habitats present and undertaken a full Environmental Impact Assessment. The Pre-planning Application Consultation (PAC) includes the full suite of information that has been prepared following the full consideration of the proposal.

Stakeholder engagement undertaken since 2019 (OBC and FBC stages) to date:

• 1 drop-in sessions during OBC (1x in 2019)
• 3 drop-in sessions during FBC (2x in 2025 and 1x in 2026)
• PAC notice and response period extended (6 week period)
• Website and social media updates during FBC
• Discussion with Town Council and Local Councillor
• Statutory and non-statutory consultation during OBC and FBC

The proposal has been developed to a point where planning and marine licensing consents can be submitted. The intention is to submit both planning and marine licensing applications by June, 2026. The planning and marine licensing process will both include opportunities for further public consultation and the authorities will take public representations into account when deterring such applications.

Consenting for such large-scale projects can be a lengthy process. It is anticipated that a determination will be known by the end of this calendar year at the earliest.