Coastal and Inland Waterway Engineering
Coastal & Inland Waterway Engineering
Protecting and preserving our marine infrastructure
Rising sea levels, increased flood events, climate change, and coastal erosion continually threaten coastal, river, and estuary structures. At Kaymac, we provide innovative and expertly planned engineering solutions to repair, reinforce, and safeguard these vital assets.
What We Do
- Underwater inspections & assessments: Our commercial dive teams conduct detailed structural surveys, thickness measurements, and condition assessments to diagnose issues accurately.
- Structural repairs & restorations: From lock gates and culverts to bridge abutments and embankments, we offer targeted repair strategies—including masonry/timber work, grout injections, shotcrete applications, and structural strengthening .
- Scour protection & erosion control: We design and implement scour solutions using rock rolls, mattresses, terralock anchors, and in situ marine-grade concrete—tailored to tidal and river environments.
- Temporary works & confined access systems: Our CITB-qualified teams engineer bespoke access systems and temporary works (e.g., cofferdams, dams, pontoons) to ensure safe, precise operations in challenging environments
- Comprehensive waterway services: Whether managing saltmarsh realignment, constructing jetties, or upgrading tidal infrastructure, we support coastal and inland waterway projects from concept to completion
Demolition and Installations
Our coastline is dotted with unused pontoons, piers, jetties and other coastal structures. When they’re impossible to repair, demolition is required. But that’s no easy feat given the risks to the local environment, users, and wildlife.
Kaymac can safely demolish – and replace – structures like jetties, penstocks, weirs, and fish passes. We’ll begin with an underwater inspection to see whether the structure can be repaired. If demolition is needed, our engineers will design a solution using the latest techniques and materials.
Our commercial divers are skilled in a wide range of operations, from underwater structural inspection to demolition, removal, and new installations. We’re experts in working underwater, and our in-house delivery team will plan and manage your project from preparation to clear-up.
Get in touch to discuss your demolition project.
Cofferdams
Kaymac designs and installs bespoke cofferdam solutions to create dry, stable working environments in challenging marine and inland waterway conditions. Our in-house teams are experienced in delivering temporary dam systems in confined, high-risk, or logistically complex sites—enabling safe and efficient execution of works below the waterline.
We engineer each cofferdam system to suit site-specific hydrodynamic, geotechnical, and environmental conditions. Depending on the ground composition, tidal constraints, water depth, and project duration, we deploy a range of solutions, including:
- Steel sheet pile cofferdams – Installed using vibro or impact hammers, these provide robust water exclusion and structural support in deeper or fast-flowing environments.
- Dumpy sandbag cofferdams – A flexible option ideal for soft bed materials or sites requiring rapid mobilisation and minimal plant.
- ‘KayDam’ modular dam system – Our proprietary portable cofferdam, designed for deployment in shallow water or tidal zones, allows operatives to work within a secure containment bund, significantly reducing environmental risk and improving safety.
All systems are designed in-house with full temporary works calculations and method statements, ensuring compliance with CDM regulations and environmental permitting requirements. Our cofferdam solutions prioritise minimal ecological impact while delivering maximum access and stability for the works.
🔗 Learn more about our engineered access systems on our Innovative Temporary Works page.
Pile Protection
Our engineers apply the latest techniques to provide exceptional services in pile protection.
Our team can handle these complex projects from start to finish. We’ll start with an inspection to obtain key measurements and see what clearing will be needed.
We are approved installers of Denso’s Seashield 500 system, which is suitable for timber, steel and concrete piles and other marine structures. It’s essentially a reinforced ‘jacket’ which is filled with cement to provide extremely effective, long-lasting protection against erosion.
Throughout our pile protection projects, we work with and around the environmental and tidal conditions, drawing on our experience to predict and mitigate risks.
With over 40 years of experience in outfall pipeline solutions, Kaymac offers a fully integrated in-house service—spanning inspection, design, and delivery. Our operations team includes highly skilled commercial divers and multi-disciplined civil operatives who are equipped to carry out detailed inspections both above and below the waterline. These frontline teams gather critical condition data, assess structural integrity, and establish safe access strategies for even the most complex or confined environments.
This diagnostic phase feeds directly into our in-house engineering department, where solutions are developed in close collaboration with site operations. Whether the requirement is to install new assets, replace ageing infrastructure, or carry out targeted remediation of existing pipelines or chambers, our engineers tailor each design to meet specific hydraulic, structural, and environmental conditions.
Once designed, the solution is delivered through our internal delivery model, ensuring full continuity from concept through to completion. Our in-house delivery teams implement works efficiently and safely—minimising disruption to surrounding infrastructure and sensitive environments. Throughout, we apply a value-engineered approach that maximises performance while optimising cost, supported by transparent communication with clients and stakeholders.
The result is a high-quality, durable solution that serves the long-term needs of both asset owners and end users.
👉 See more on our Outfall and Pipelines page.
Lock gate maintenance
Our specialist team has inspected, repaired, and replaced lock gates all over the UK. Whether we’re just checking one or a dozen, we’ll apply the same attention to detail and draw on our experience to recommend the best solution.
First, our expert divers will assess the condition of each lock gate, checking the cills, cill rubbers, quoins, mitres, pintles, bolts, and masonry. We use ultrasonic gauges as well as physical tests to check the strength and integrity of crucial components.
After compiling a report, our team will recommend the appropriate lock gate maintenance or solution. Our commercial divers – all trained in different trades – can then work on your repairs, installation or removal.
Lock gate maintenance is a core part of our contract with the Bristol Port Company, which retains Kaymac to service lock gates in Avonmouth and Royal Portbury Dock.
Other services offered are embankment stabilisation, lifting operations, spray concreting and Scour Protection works.
Why Choose Kaymac?
✅ Multi-disciplinary expertise
We bring together commercial diving, civil engineering, confined access specialists, and temporary works designers—all coordinated under one roof .
✅ Proven track record
From Swansea to the Severn Estuary, our projects include tidal outfalls, scour schemes, lock gate refurbishments, and more—delivered safely, on time, and within budget
✅ Safety and sustainability embedded
We operate under ISO 9001, 14001, and 45001 standards. With HSE, ADCI protocols, and robust environmental measures, our projects protect both people and ecosystems
✅ Holistic delivery model
Our end-to-end “Detect–Diagnose–Develop–Deliver” process gives clients expert guidance and certainty, from initial surveys and feasibility to design, execution, and asset handover
✅ Client-focused results
With a family-run ethos and national reach since 1976, we pride ourselves on open communication, flexible resourcing, and long-standing client relationships
Client Success Stories
“Kaymac have always provided an excellent, economic, efficient … delivered quality workmanship, safely, to programme and within available budget.”
– Gordon Randlesome, Principal Engineer, Swansea Council
“Flexible around the tides … quality management & handover processes are robust and proactive.”
– Ian Russ, Port Engineer, Bristol Port Company
Ready to Strengthen Your Infrastructure?
Let’s connect.
Contact our coastal and inland waterways team today on 01792 301 818 or contact us to discuss your project, receive a free initial assessment, or arrange a site visit.
