Emergency Response to Culvert Collapse
September 2025
When a culvert within a tidal river in Swansea partially collapsed, Swansea City Council called upon us to deliver an emergency response. The failure not only threatened local drainage infrastructure but also caused a large sinkhole to open beside a popular cycle route, creating an immediate public safety risk and forcing the route’s closure.
The culvert carries surface water from a wide catchment area, meaning heavy rainfall events could have rapidly worsened the situation. With tidal conditions, unstable ground, and restricted access all in play, the project demanded rapid mobilisation, innovative engineering, and careful management of safety and environmental risks.
The Challenge
The site presented multiple technical and safety challenges. The partially collapsed culvert posed a constant threat of further collapse, while the tidal river created narrow working windows and unpredictable water levels. Access to the failure zone was highly restricted, with no conventional safe working area available.
Weather conditions also presented an ongoing risk, with rainfall capable of increasing flows through the damaged structure and hindering progress.
The Solution
To stabilise the structure and create safe working conditions, Kaymac implemented a bespoke temporary works and flow management system.
Downstream, the Kaydam system was deployed to withstand tidal forces and create a dam within the river, creating a dry working area. Upstream, a temporary dam and over-pumping system diverted flows away from the work zone.
A custom modular steel access and support system, designed with Kingswood Engineering, enabled safe entry into the collapsed culvert for inspection, debris removal, and repair works — all while minimising the risk of further failure.
All works were meticulously phased, allowing for continual reassessment in response to weather and tidal changes.
Environmental Collaboration
Given the environmental and heritage sensitivity of the site, Kaymac worked closely with Natural Resources Wales and HENEB to secure the necessary approvals before commencing work. Regular updates, inspections, and open communication ensured the project met all environmental and heritage requirements throughout.
The Outcome
Despite challenging site conditions and a tight 10-week programme, the project was completed on time, within budget (£650,000), and without safety incidents. The culvert was successfully stabilised and returned to full functionality, and the sinkhole repaired — allowing the adjacent cycle route to safely reopen to the public.
Client Feedback
“Swansea Council were extremely impressed with the professionalism and efficiency demonstrated by Kaymac Marine Limited during the recent Morfa culvert repair project. The project was completed on time and under budget, which is a testament to their meticulous planning, skilled workforce, and commitment to excellence. Their communication throughout was clear and proactive, ensuring all stakeholders were kept informed and aligned.”
– Paul Retallick, Team Leader – Bridges and Structures, Swansea Council
Delivering Under Pressure
This emergency response highlights Kaymac’s ability to deliver technically complex civil engineering works under extreme conditions. Our team’s expertise in tidal working environments, bespoke temporary works design, and collaboration with statutory bodies ensures critical infrastructure remains safe, operational, and resilient.
