Flooding in the UK: The Role of Flood Alleviation Schemes

As the UK faces increasingly frequent and severe flooding, flood alleviation schemes are playing a vital role in helping communities adapt to a changing climate. From engineered barriers to nature-based solutions, these projects help us to build resilience, protect habitats and address the environmental challenge posed by increased rainfall levels flood risk, rising seas and expanding urban areas.

After an overview of the current flood threat in the UK, we outline typical flood defence strategies, highlight some successful property flood resilience measures, and summarise recent shifts in government funding that could affect how future defences are delivered.

The Challenge of Flood Risk in the UK

According to the Environment Agency’s latest National Flood Risk Assessment, around 6.3 million properties (homes and businesses) currently lie in areas at risk of flooding from rising sea and river levels or surface water. Due to climate change, by mid-century that number may rise to 8 million properties facing long term flood risk.

That flood risk increase is driven by several factors:

• More extreme rainfall events: according to the UK Centre for Ecology & Hydrology, intense rainfall is becoming more common due to the climate emergency, along with flash flooding, putting pressure on river catchments, groundwater, and urban drainage systems.
• Rising seas and storm surges: coastal and estuarine defences will increasingly be tested by severe weather, particularly during storms and high tides, creating the need for a flood emergency plan. Coastal erosion compounds the susceptibility in certain areas.
• Land use change and urban expansion: more impermeable surfaces, drainage networks under pressure, and development in flood-prone zones amplify flood risk.
• Multiple sources of flooding: many properties are simultaneously vulnerable to river overflow, surface water flash flooding, groundwater rise, or coastal floods.

Beyond people’s houses, flood risk endangers transport infrastructure, water treatment works, pumping stations, and agricultural land. The Environment Agency’s new assessment of extreme weather notes that 38% of roads and 37% of rail lines in England lie within flood-vulnerable zones, a figure that could rise to 46% and 54% respectively due to climate change.

Where is Flood Risk Highest?

• Low-lying and coastal zones: parts of East Anglia, Lincolnshire, Norfolk, Kent, Sussex, and the east coast in general are especially exposed to tidal flooding and storm surges.
• River basins and upland catchments: regions such as Cumbria, Yorkshire, Somerset and the West Midlands often see heavy rainfall levels: steep slopes and fast run-off lead to river flooding and flash events.
• Urban and surface water risk areas: cities in floodplains or with constrained drainage (for example parts of London, the Thames corridor, and low-lying river towns) face surface water flooding in intense storms.
• Socially vulnerable localities: the “Social Flood Risk Index” highlights that flood risk intersecting with deprivation concentrates vulnerability in places like Hull, Boston, East Lindsey, Glasgow, Newham, and Leicester.

Examples of Stressed Towns which issue a frequent Flood Warning

Towns like Skegness, Boston, Lincoln, and Hull are often flagged in regional risk assessments and have current flood warnings systems. Cardiff, parts of London, Warrington and Barking & Dagenham came in the top four places deemed at risk in a study that used climate crisis data. Some communities with a history of severe flooding and flood damage are already facing issues with insurance companies that will not cover flooding: for example, Tenbury Wells in Worcestershire is being described as increasingly uninsurable due to recurring flooding.  

How Flood Alleviation Works

Flood alleviation schemes reduce risk in several ways:

• Storing excess water in reservoirs, washlands, or wetlands.
• Slowing the flow by increasing infiltration and reducing run-off.
• Diverting water to safer areas or temporary basins.
• Protecting infrastructure with barriers and engineered structures.
• Building resilience so communities can recover more quickly from flood events.

In many cases, the ecological benefits of measures to control flood waters are as significant as the flood protection: restored habitats, cleaner water, and enhanced carbon storage are all positive outcomes of well-designed schemes for flood risk, water and drainage.

Typical Flood Alleviation Approaches

Flood alleviation schemes use a combination of engineered defences, nature-based measures, and land management to reduce risk. The most successful schemes blend multiple techniques in the areas affected.

Engineered defences to tackle flood risk

These are traditional structural interventions designed to keep floodwaters at bay and include flood walls, embankments and levees to protect key assets in extreme weather scenarios. While they are reliable, durable, and provide precise protection, they can be expensive, require maintenance and interrupt landscapes or ecological connectivity. This strategy may encourage development behind such `lines of defence,’ setting up future risks.

Pumping stations and sluices

Pumps actively remove water from low-lying land, while sluices regulate flow into or out of storage areas while drainage channels and culverts move water away. They are vital for areas below sea level or tidal influence, but they are energy-dependent, can fail or overflow in extreme events and require upkeep.

Movable barriers

These can provide flexible tidal protection, for example the Thames Barrier, and can be raised when needed during a flood warning and left open otherwise, making them less intrusive when inactive. However, they are technically complex and limited in height.

Flood storage basins and washlands

By temporarily holding flood water and releasing it slowly downstream, this method is effective at moderating flood peaks and can have a lower ecological impact. However, as it requires land, there is potential for schemes to create conflict with agricultural or development use.

While effective, hard engineering can be expensive and ecologically disruptive, which is why more projects now combine it with natural approaches.

Nature-Based Solutions to reduce Flood Risk

Also known as Natural Flood Management, these techniques harness ecological processes to slow, store, and filter water:

Wetland and floodplain restoration

This gives rivers room to overflow safely. Creating flood corridors or allowing controlled flooding in designated zones can reduce the risk of more flooding elsewhere.

Riparian (riverbank) planting, buffer strips and woodland creation

These measures reduce flood risk by helping absorb rainfall and stabilising soil.

Sustainable Drainage Systems (SuDS)

Installations such as rain gardens, swales, and permeable paving manage surface water flooding on hard surfaces in towns and cities.

Leaky dams

In upland streams this relatively low-cost method reduces the speed of water, allowing a semi-natural flow. Leaky dams are often complementary to other measures; however, while they can help reduce flood risk, they have limited capacity when presented with a severe flood warning and may silt up.

Soil management and agricultural practices

Working with farmers to adopt regenerative practices such as reduced tillage, cover crops and grass buffer strips, helps soil retain water and reduce surface run-off.

These solutions deliver multiple benefits beyond flood protection: improving biodiversity, water quality and contributing to carbon sequestration over a long period, but they do generally require larger areas and flexible thinking.

Hybrid or Integrated Approaches

The best schemes combine both approaches. Engineered structures may provide core protection, while upstream nature-based measures reduce flow peaks and create ecological value. This `catchment-wide’ thinking is increasingly the model for modern flood risk management.

Examples of Successful UK Schemes

Here are a few examples of where flood alleviation has been successfully applied – or is underway – using techniques that reflect ecological thinking:

Clifton and Rawcliffe Ings, York

These flood meadows along the River Ouse serve as washlands, temporarily storing up to 2.3 million cubic metres of floodwater during peak events. This reduces flood levels in York by around 150mm, protecting people living in the city while maintaining the land’s ecological and agricultural value.

Pickering, North Yorkshire

The ‘Slowing the Flow’ project is a landmark example of nature-based flood management. Using a combination of woodland planting, leaky dams, and floodplain reconnection, it has significantly reduced flood peaks in the town without the need for large-scale walls or barriers. The scheme demonstrates how working with natural processes can deliver effective protection at a fraction of the cost of traditional engineering.

Canvey Island Flood Defence Renewal

In July 2025, the government announced the near completion of Canvey Island’s £75 million flood defence renewal, upgrading 3km of tidal defences and securing protection for over 6,000 homes.

Somerset Levels

Following the severe 2013–14 floods, investment was made in drainage improvements, pumping infrastructure, and wetland restoration. The approach now balances farming, flood management, and habitat conservation and is an example of multi-functional landscape management.

Boscastle, Cornwall

The 2004 Boscastle flood, caused by intense rainfall, prompted changes to catchment management, improved drainage and resilience in upland tributaries.

These examples show that at different scales, from upland tributaries to floodplains to coastal defences, a combination of methods can work effectively to combat long term flood risk.

Government Funding and Policy Changes

Flood management is a national priority and recent government announcements reflect the growing urgency. In October 2025, the UK government pledged £10.5 billion to protect up to 900,000 properties at risk of flooding through new and improved flood defences.

Key funding changes include:

• Simplified application processes enabling local authorities and smaller communities to access funding more easily.Updated eligibility rules that allow a wider range of projects, including nature-based schemes, to qualify under the Flood and Coastal Resilience Partnership Funding model.
• Additional capital funding, with £2.4 billion allocated over 2024–26 for new flood defences. However, the government also signalled that “significant funding pressures” may require revisiting plans in future years.

Public Perception

There has been discussion in some media and policy forums about the need to keep increasing spending on flood defence funding to keep pace with the rising risk to critical infrastructure.

A Public First report `From risk to resilience’ (March 2025) revealed that 66% of the UK public don’t think their area is prepared for flooding and say that the Prime Minister’s  call for `national security for national renewal’ should involve flood resilience. Nearly 2m people in UK are exposed to flooding each year; the situation is set to worsen, threatening long term growth. The report stated that flood prevention is good investment: every £1 spent on flood prevention saves £8 in damages. 

An AXA UK study (Nov 2024) found that 55% of those polled said flooding was perceived to be the greatest risk in the next decade, and homes and businesses with the highest chance of flooding face at last £818m in costs by 2055.

Building Resilience for the Future

Flood risk across the UK is clearly growing in scale, complexity and urgency. The Met Office climate predictions of higher rainfall levels and extreme heat put pressure on water companies and the Environment Agency to reduce the risk of flooding, as well as the emergency services who increasingly deal with flood situations.

However, well-designed flood alleviation schemes, especially those that blend good engineering with ecological insight, can significantly reduce long term flood risk. The recent surge in government funding for flood resilience measures and policy reform offers a unique opportunity for ambitious, effective projects.

Successful schemes depend on:

• Catchment-scale planning that considers whole systems, not just local fixes.
• Hybrid solutions blending hard infrastructure with natural processes.
• Adaptive design that can evolve as conditions change.
• Ongoing maintenance and monitoring to ensure long-term effectiveness.
• Stakeholder collaboration, engaging landowners, communities, and regulators early on.