The climate crisis is no longer some distant prediction – its making itself felt right now in changing weather patterns that are rewriting the rule book on earthworks across the country I’ve spent my whole career working on transport and flood defence schemes in England and beyond, and what I see now is climate change quietly taking its toll on the earthworks that were never designed to cope with the weather we now see.
Earthworks in the UK involve shaping the land – digging out and filling in – and they’re a crucial part of how we build our roads, railways and major infrastructure projects. But the truth is that many of the UK’s major infrastructure projects were built using standards that are virtually unrecognisable from the way we think about earthworks today. We’re talking about a portfolio of ageing assets built between the 1840s and the 1970s, many of which are showing signs of strain under the weight of climate change.
The UK’s rail network alone stretches to over 10,000 km of embankments that were built to last, along with thousands more kilometres of highways, canals and flood defences. These ageing structures are now facing the new reality of hotter drier summers, warmer and wetter winters, and rising groundwater levels in some of the most vulnerable areas. You can see the impacts now, and they’re only getting worse.
The policy backdrop for all this is pretty clear. The Climate Change Act 2008 set the framework for dealing with climate change, and the UK has set a target of Net Zero by 2050. And as a result of that, we’re being driven to not just reduce our emissions but also to make our infrastructure more resilient to the impacts of climate change. So earthworks design, construction and asset management now need to be thought of as part of a climate resilience effort, not just as the cheap stuff that gets done on the side.
This article is an overview of how we can approach this in a more practical way, looking at the best technical approaches, risk strategies and design details. It references uk earthworks / groundworks services – and it sets out why the future of earthworks needs a complete rethink on how we design and build them.
The UK’s Changing Climate and What it Means for Earthworks and Slopes
The Met Office has been saying for years that UK weather is getting more extreme – and its latest projections just confirm that. Temperatures are up, rainfall is changing, and extreme weather events are getting more frequent and more severe. And every two years, the Climate Change Committee checks in on how we’re doing on adapting to all this, and what they say is that earthworks are one of the biggest and most growing risks out there.
So what are the main risks for earthworks and slopes in the UK? Here they are in a nutshell:
- Heat. I mean we’ve just seen a whopping 40.3°C in Coningsby in Lincolnshire this summer – which is just about unthinkable even 20 years ago. What that means is that clay fills dry out, crack open and become pathways for water when it eventually arrives.
- Intense storms. We saw it with storms Ciara and Dennis in February 2020 – an awful lot of rain came crashing down, and it just about overwhelmed our drainage systems. And then in the SE we had 130-154% of the long-term average in just a few months, which as it happens directly correlates with a big spike in failures.
- Drought and deluge. This is a cyclical pattern that’s really damaging. Shrink swell behaviour in clays – such as London Clay, Weald Clay and Oxford Clay – progressively weakens the soil over repeated seasons.
- Sea level rise and erosion. Coastal embankments are facing a lot of pressure from rising tides, storms and erosion.
And you know the mechanisms behind it all pretty well. Desiccation cracks in fills can reduce matric suction and shear strength. Long term wetting raises pore water pressures. Surface water erodes and undermines slope geometry. And then there are the old drainage paths that are either silted up, collapsed or just can’t cope.
These hazards combine with ageing assets that were never really built with resilience in mind: uncontrolled fills with no filter criteria, no geosynthetics and steep slopes that would never be allowed today. Climate risk assessments and adaptation reports now inform infrastructure standards and strategies to reduce emissions, and that needs to account for the resilience of the stuff we’re building.
Lessons from UK Earthwork Failures and Near Misses
Earthwork failures are never just one thing going wrong – they’re a combination of geology, construction history, drainage state, vegetation and weather all coming together. What’s changed is that climate loading is now a much more dominant factor.
Edenbridge, Kent (December 2019) – a railway embankment that just about reached its design height of 10.5 metres failed catastrophically after being pounded by weeks of heavy rain. This embankment, built on Weald Clay over alluvial sand in the 1830s, was starting to show its age. The 27 degree slope angle wasn’t helping – neither were the poorly functioning culverts and ditches which let water in at the bottom, causing the foundation to give way and trigger a complete failure. The line was shut for weeks while repairs were carried out. Looking back, it would have been a whole lot easier if they’d had measures in place like granular fill replacement, a 600 mm drainage blanket at the base and some rock mattress protection at the bottom – that would have knocked the risk of failure on the head.
Old Dalby Test Track, Leicestershire (December 2023) – nearly a kilometre of embankment had given way after prolonged heavy rain. The soft clay at the heart of the thing, combined with some nasty elevated pore water pressures, had triggered a steep slide at the top and a slip at the bottom. Emergency work was required to clear 17,000 tonnes of failed material and replace it with 20,000 tonnes of granular fill & fitting new drainage along 370 metres of the embankment.
Balcombe, West Sussex. This particular embankment, 15 metres high with some pretty steep angles of 34°–37°, had been gradually showing signs of movement since the 1970s. By 2020, the inclinometers were telling a pretty clear story – this embankment was still moving. Eventually a more robust solution was needed – a gravity retaining wall & a piled wall & some proper drainage at the bottom & even some berm work – all quite an expensive business, especially since it was a live railway corridor.
You can see the lessons from these embankment failures coming through loud & clear. Not least that drainage needs to be a lot better than people thought, especially with the sort of rainfall we’re now seeing. You can’t skimp on the detailing at the top or the bottom of an embankment – you need to make sure water can’t get in and accumulate. And if you’re monitoring an embankment, get on with it quickly when you see any movement happening – that way you can avoid a full-blown disaster.
UK Government Policy, Regulation and Carbon Budgets: The Framework for Climate-Resilient Earthworks
It’s worth remembering that technical design choices aren’t made in isolation – they exist within a policy framework that’s now very focused on reducing both climate change and greenhouse gas emissions from our infrastructure investments.
The Climate Change Act in 2008 set up the Climate Change Committee to advise the government on climate matters, all part of the Act. They’re responsible for advising on those legally binding carbon budgets – like Carbon Budget 7, which sets targets for 2038 to 2042 – and on national climate risk assessments. And they also oversee the adaptation reporting power which says that operators of critical infrastructure need to tell us how they’re managing climate risks.
Transport accounts for about a quarter of all greenhouse gas emissions here in the UK and it’s one of the main sources of greenhouse gases when it comes to policy and infrastructure planning. The government has said that it wants to move towards net zero carbon and, for earthworks, that means having to balance two competing requirements: building something that’s going to withstand the changing climate, while at the same time cutting the greenhouse gas emissions from its construction.
In practice, this means that carbon budgets & net zero strategies have quite a big impact on earthworks:
- Refurbishing rather than rebuilding when safety allows, which avoids all the embodied carbon of a full teardown & rebuild.
- Choosing lower carbon materials such as recycled aggregates or supplementary cementitious materials for soil stabilisation, which reduces our reliance on traditional cement.
- Optimising designs which balance the embodied carbon of building it in the first place against the whole-life cost and durability of the end product.
The key UK infrastructure standards – the likes of the DMRB for highways & Network Rail’s geotechnical asset standards & CIRIA guidance documents – are all getting more and more integrated with climate change considerations. And for highway schemes now, it’s common to apply climate uplift factors to drainage design under LA114 guidance.
The tension there is real – but it’s manageable: earthworks need to withstand the changing climate, but also to be built with lower greenhouse gas emissions – which means efficient design & construction methods. Engineers who see these as competing objectives rather than complementary ones will find themselves out of touch with the regulatory expectations & the direction of the economy.
Climate-Resilient Design Principles for New Earthworks
Time to get down to some specific guidance for civil & geotechnical engineers who are specifying new infrastructure across the UK. Something like a motorway widening near Bristol or a new rail spur in the Midlands or a flood defence embankment on a tidal estuary – it’s all the same story. The core principles for climate-resilient design are the same.
Design for Future Hydrology
When you design any sort of earthwork, use future rainfall scenarios or uplift factors from the get-go. The current best practice is to design for the end climate we can expect to see over a 60 to 120 year asset life. And make sure that you integrate both deep drainage and surface drainage right from the start, not as afterthoughts during detailed design.
Material SelectionChoice of Fill is the Key to it All
Its your earthworks project. So its fundamental to give some preference to materials that can be relied upon. When you’re building up soil ( positive earthworks ) or cutting into the landscape ( negative earthworks ) you ought really give well-graded granular or low-plasticity cohesive materials a go where you can. For construction project requiring free-draining fill, Building Sand is a popular choice, while cement, shingle and limestone are often used for structural and drainage applications.
Techniques in earthworks include digging basements and compacting soil to create stability. Getting soil removal and its addition right also needs some thought. Cut and fill operations balance the removal of soil with adding more to it to keep the amount of extra material that has to be moved to a minimum. You also need to consider excavation which can involve removing soil and rock to lower ground levels for all sorts of construction projects, and site preparation which includes getting rid of topsoil and shaping it for construction.
Acceptance criteria for site-won soils have to be rigid, with testing regimes that take into account expected moisture extremes rather than just on what conditions the material is placed on.
Going with the Flow of the Climate
Flatter slopes should be specified if at all possible as long as land is available. Putting in berms and benches on high embankments and cuttings can reduce the driving forces on potential slip surfaces, introduce some redundancy, and make maintenance easier. Increased crest widths can then accommodate drainage infrastructure, fencing, access tracks and utilities.
Giving Your Interfaces the Attention they Need
Failures often start at interfaces, these are things like abutments, culvert inlets and outlets and retaining walls and where localised erosion, differential movement and water getting trapped creates weakness. These details really need a lot of design attention and you should be specifying for a range of different climate scenarios, not just what might happen during the design event.
Groundwater, Surface Water and Drainage Design for a Future Climate
Many legacy earthwork failures start off as drainage problems and climate projections can only make things worse with more intense downpours and changing groundwater regimes. Earthworks are vital for ensuring structural stability and managing drainage properly, and proper grading and site shaping prevents water collecting across the slope profile.
Designing for a Climate-Informed Surface Drainage
You should be using updated rainfall intensity–duration–frequency (IDF) curves taking in to account climate uplift in your design. By shaping your land you can ensure rainwater run-off is safely directed away from your structures and into controlled outfalls. The key elements include:
- Swales and ditches sized for future storm scenarios and with plenty of room to spare
- Culverts designed to at least a 1-in-100 year event plus climate uplift, rather than sticking with legacy 1-in-50 year assumptions
- Erosion-resistant linings at high-velocity locations
- Outfalls properly detailed with energy dissipation and scour protection
Deep Drainage for Earthworks
When you’ve got slopes that are just going to be sensitive to pore water pressure build-up, deep drainage is going to be a must:
- Chimney and blanket drains intercept water passing through the fill body
- Toe drains relieve pressures at the base of embankments and behind retaining structures
- Perforated pipes with graded filters and geocomposites maintain flow for decades without getting clogged
The interaction between groundwater, perched water tables and seepage is going to govern slope stability in many UK geologies. Piezometer data and numerical seepage–stability modelling are what you need where risk is high.
Maintenance needs to be designed in from the start. Access for inspection and jetting, safe manhole and catchpit layouts, and simple routes for asset owners to keep systems functional over a 60–120 year life are just as important as the drainage itself. A system that cant be maintained will fail – and the cost of that failure, in both money and disruption, far exceeds the cost of getting the design right.
Soil Behaviour in a Warmer, Drier, Wetter UK: Geotechnical Considerations
The geotechnical science behind climate impacts is all well established, but the implications for design are still not properly reflected in routine practice.
Wetting – Drying Cycles
Repeating wetting and drying cycles does some real damage to high-plasticity clays. London Clay, Weald Clay and Oxford Clay all exhibit significant shrink – swell behaviour. During dry periods, desiccation opens up fissures and cracks. During subsequent storms, these cracks act as rapid infiltration pathways, and reduce matric suction and shear strength far faster than uniform wetting would. Over multiple seasons, progressive softening and strain accumulation brings the soil closer to residual strength – the point at which failure becomes likely.
Soil compaction does increase soil density to prevent future settlement and create a stable base, but even well-compacted cohesive fills lose strength under sustained cyclic moisture loading if the soil is inherently moisture sensitive.
Temperature effects
Higher temperatures have an influence on soil suction curves, pore water pressure dissipation rates, and the creep behaviour of geosynthetics. These effects are often left out in routine design but become significant over a multi-decade asset life in a warming climate.
Investigation and Testing
Where cyclic moisture is going to be a problem, investigation and testing need to go beyond just looking at standard Atterberg limits:
- Extended suction and resilience testing under cyclic moisture paths
- Long-term triaxial and direct shear tests under varying suction states
- Incorporation of climatic boundary conditions in numerical modellingPractical design responses include making sure you’ve got the right moisture window for compaction, protecting those compacted surfaces before you bring in the topsoil, and using capping layers or lime stabilisation where you’re worried about repeated wetting and drying cycles. These are really worthwhile measures that bring a lot of benefit for not too much extra cost.
Vegetation, Biodiversity and Nature-Based Solutions on Earthworks
Vegetation plays a double role on earthworks – both as a tool to help stabilise the soil and as an asset for the environment. Root systems do a great job of keeping the soil stable near the surface, stopping erosion and helping to release water back into the atmosphere – but they can also dry out high shrink-swell clays if you’ve not chosen the right kind of plant. And when you do earthworks, you can really disrupt local ecosystems and end up chucking a lot of carbon into the air during construction – which is why thoughtful revegetation is just about essential for both geotechnical and environmental reasons.
Earthworks are not just about piling up dirt – they can also transform the terrain into some really useful outdoor spaces for landscaping. And when it comes to selecting the right plants for the job, you need to think about the future climate and make sure you’re picking drought-tolerant grasses and low shrubs that can handle longer, hotter summers. Native or near-native mixes that support biodiversity and pollinators are also a great choice, while avoiding very deep-rooting species near critical structures (where they might cause cracking) is a must.
Ragstone is a popular choice for landscaping and construction, often used in combination with some really clever bioengineered erosion control like coir rolls, live staking and brush layering. And vegetation swales, filter strips and wetland features at the bottom of slopes or outfalls can all be part of a nature-based solution that complements your engineered drainage – all of which helps to support biodiversity net gain, improve landscape integration and sequester a bit of carbon in the soil and biomass.
Retrofitting and Upgrading Existing Earthworks Assets
Most of the climate-related risk doesn’t come from brand new earthworks – it’s all the old ones that were built to last another day. Network Rail, for example, has over 190,000 earthworks assets to manage – 100,000 embankments, 70,000 soil cuttings and 20,000 rock cuttings – and many of them are over 100 years old. Between 2004 and 2020, they had 1,864 earthwork failures on GB mainline railways.
Some common upgrades include:
- Regrading and buttressing – widening the base, flattening the slope, and building in some berms
- Installing or renewing drainage – whether that’s deep drainage or surface drainage – including replacing those failed culverts, adding in some toe drains, or installing some chimney drains
- Using local soil nailing and facing systems for when you can’t regrade the slope at all
- Erosion protection at critical points like culvert inlets, outlets and bridge approaches
When you go digging for earthworks, you can end up unearthing some pretty interesting historical sites – which can add some real archaeological constraints to your retrofit programme. So, risk-based asset management is all about prioritising which slopes to fix first, based on how likely they are to fail, how bad the consequences would be if they do fail, and how exposed they are to future climate loading.
Doing the work on live networks means you have to get the construction sequence just right. Which is why Earthworks has got a wide range of tool and plant hire options available – including diggers and dumpers that are perfect for tight sites. We can deliver tools across Kent and the wider southeast.
Between 2006 and 2012, Network Rail spent around £90 million a year on earthworks maintenance. In the Eastern region alone, earthworks failures caused £4.2 million in delay costs and around 55,000 delay minutes over a two-year period. It’s a pretty big challenge to get all these earthworks sorted, but the cost of not doing it is even higher – in terms of taxpayer money, disruption and safety risk.
Monitoring, Instrumentation and Smart Asset Management
Earthworks aren’t just something you can just leave to weather passively – a climate-resilient earthworks system needs to be actively managed and monitored. Which is why data is playing an increasingly important role in managing climate risk on critical transport and flood defence assets.
You still need the traditional geotechnical instruments like inclinometers, piezometers and settlement plates, but there’s some new technology that’s really pushing the boundaries:
- Remote sensing and satellite InSAR that can detect really tiny ground movements across a whole route corridor
- IoT-enabled sensors that send back real-time data on pore pressure or displacement
- Weather-linked trigger and alarm systems that will introduce some precautionary speed restrictions or closures ahead of a big storm
All of that monitoring data feeds into your risk models, early warning protocols and targeted maintenance programmes – which really helps to keep people safe and get the best value out of your budget. The Balcombe embankment case is a great example of how inclinometer data can help you plan for a problem before it becomes a disaster.
There’s still a few challenges to overcome – including getting people with the right skills to interpret the data and dealing with false positives that can erode your confidence in the system. But the direction is clear: smart asset management is not optional for organisations managing earthworks at scale in a changing climate.
Integrating Earthworks with Groundworks, Foundations and Structures
Earthworks are a key part of the whole infrastructure picture – so it makes sense to think about how they fit in with the rest of the project. From groundworks to foundations to structures, it’s all about finding a way to get everything to work together.
Earthworks can end up interacting with all sorts of underground utilities and infrastructure – so it pays to plan ahead and make sure that all the different bits are properly coordinated. And from a construction perspective, it’s all about finding the right balance between getting the job done on time, on budget and to the right quality. Which means thinking carefully about how to sequence the work and when to bring in the different specialist contractors.
In the end, it’s all about delivering a project that’s safe, reliable, and meets the needs of the people who will be using it. Which means working closely with all the different stakeholders – from the client and the engineers to the contractors and the end-users – to make sure that everyone is on the same page.Earthworks dont stand alone. They often interface with groundworks, retaining walls, culverts, bridges and pavements which all experience loads that are affected by the climate. Earthworks ensure the ground has enough bearing capacity to support buildings and earthworks are vital for creating stable foundations and keeping soil stable for lots of different types of infrastructure.
Critical areas where the interface is particularly tricky include:
- Embankment to bridge abutment – you dont want to get differential settlement and water got stuck at the rigid/flexible boundary
- Cuttings that tie into piled or mass concrete foundations – need to make sure drainage keeps going and your filters are compatible
- Approaches to culverts and underpasses – where water and geotech issues really start to intersect
Climate change makes these interface problems even worse: with stronger peak flows, scour at abutments gets worse, joint openings and water getting in get worse at the rigid/flexible transitions and loss of fines at the edges of pavements on embankments accelerates under more intense rainfall. Getting the structural and geotechnical teams to design earthworks, groundworks, foundations and drainage together is absolutely key to making sure they all behave as a system over time.
Delivering Low-Carbon, Reducing Emissions, Climate-Resilient UK Earthworks Services
For consultants and contractors who offer uk earthworks services, its all about balancing resilience with decarbonisation on every project. This isnt some abstract policy, it affects what we do every day when we are planning, specifying and delivering work on the ground.
Modern earthworks projects focus on being sustainable by reusing materials and stopping erosion. Modern UK earthworks projects aim to reduce waste by reusing excavated material on site wherever possible. There are practical things that project teams can do:
- Sorting out options early to get earthworks volumes down through alignment and level optimisation
- Making the most of materials on site, with robust testing to confirm they are suitable
- Using modern plant, greener fuels and more efficient logistics to cut down construction emissions
Common materials include cement, shingle and limestone – and wherever possible, you should go for recycled equivalents. Standard bags of materials weigh in at 0.8 tonnes but buying in bulk and using local suppliers reduces both cost and transport emissions. In stabilisation works, using supplementary cementitious materials can really cut embodied carbon while still meeting the geotech requirements.
Transparent carbon accounting at scheme level, tied to the UK’s carbon budget framework and your organisations own net-zero plan, is starting to become expected by clients and regulators. The businesses and service providers who can do this will be in a great position as the market evolves.
Risk, Insurance, Carbon Budget and Whole-Life Cost in a Changing Climate
Climate-related earthwork failures come with big direct repair costs, disruption costs and reputational impacts. In the Eastern region, the financial cost of just two years of failures was £4.2 million in delays alone – not even counting the cost of emergency repairs and other things like that.
Whole-life cost and risk-based decision-making can justify spending a bit more upfront on more robust earthworks. Where failure consequences are really severe, like major rail corridors, strategic roads and key flood defences, the maths is clear and favours resilience. This means folding in climate allowances into probabilistic stability and flood risk assessments, and using that to guide your option appraisal.
Insurers, lenders and regulators are starting to check whether you have done a proper job of assessing climate risks. Schemes that fail to account for future climate scenarios are facing higher insurance premiums, tighter conditions and greater exposure to claims. For asset owners who care about homes, infrastructure and public safety, this is a financial AND an engineering imperative.
Skills, Standards and Collaboration for Future-Ready Earthworks
Climate-resilient earthworks demand the best professional development and cross-disciplinary collaboration. The education of geotechnical and civil engineers now needs to include the basics of climate science, uncertainty quantification and adaptive design principles.
Better integration between designers, contractors, ecologists, hydrologists and maintenance teams is needed. Professional bodies like ICE, the Geological Society, CIRIA working groups are playing a big role in spreading the word on emerging good practice through guidance, events and working groups.
Sharing data from monitoring, feedback from past projects and case studies between organisations helps refine your design rules and avoid making the same mistakes over and over. Climate resilience is a long-term, iterative process rather than a one-off design tweak. Every engineer working in this field has a job to do in helping raise the bar – and the tools, knowledge and collaborative networks are all there to make real progress within this decade.
Conclusion: Earthworks as a Front-Line Climate Resilience Discipline
UK earthworks need to be conceived, designed and managed with a changing climate in mind – not the one they were built for in the past. The evidence from recent failures, climate projections and regulatory direction are all pointing in the same direction.
The Key Technical Themes are Clear
- Climate-informed hydrology and drainage is a must – the way water flows and moves through the landscape is going to change as the climate does
- We need to make sure we’re choosing materials that will stand the test of time
- The existing network of earthworks also needs to be taken into account – we’ll want to upgrade and fix them, not just leave them to deteriorate – and then keep an eye on them to make sure they keep working
- We also need to make sure that any changes we make to our earthworks don’t do more harm than good – that means keeping an eye on carbon emissions and how they align with the UK’s goals to reduce its carbon footprint
Investing in earthworks that are good for the climate will make a big difference – it’ll keep people safe and keep our country running smoothly – and also help us meet the UK’s legal obligations to tackle the climate crisis and get on with reducing carbon emissions in line with the targets set out by the Climate Change Act
As engineers and the people in charge of looking after the earthworks, we need to take charge and make a plan – the earthworks we put in place today will still be standing in a hundred years time, so we need to make sure they’re designed and built with the right stuff to withstand the changes that are coming – and it’s not about how things used to be, it’s about how they need to be to keep up with the changes in the climate. The time to make sure that all of our earthworks decisions are with the climate in mind – from the very first idea to keeping them running and in good nick – is now
