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Expanded Leigh flood storage area and new Hildenborough defences will reduce flood-risk to 1,870 homes and 575 businesses.

A major £42 million flood scheme has officially opened, providing better protection from flooding for homes, businesses and essential services in Tonbridge and Hildenborough.

The expanded Leigh flood storage area and new Hildenborough embankment scheme will reduce flood risk to 1,870 homes and 575 businesses, while also benefiting communities further downstream along the River Medway.

The scheme has increased the capacity of the Leigh flood storage area by around 23 per cent. By raising the maximum stored water level at the control structure by 55 centimetres, the expanded storage area can now hold approximately 7.4 million cubic metres of floodwater, equivalent to around 2,880 Olympic-sized swimming pools.

The scheme will help communities respond to the growing challenge posed by climate change, with increased likelihood of more frequent, severe storms and extremely wet winters. The project has also improved the reliability and resilience of the structure, enabling it to continue reducing flood-risk for the next 50 years.

The original Leigh flood storage area was completed in 1982, and has since played a vital role in protecting downstream communities and was operated 75 times between 1981 and summer 2026 to reduce flood-risk.

Simon Curd, flood-risk manager for the Environment Agency in Kent, said:

This is a major investment in the safety and resilience of communities along the River Medway. The original Leigh flood storage area has protected Tonbridge and Hildenborough for more than 40 years, but climate change means we must be prepared for more severe storms and wetter winters.

By increasing the amount of floodwater the area can store by around 23 per cent and improving the reliability of its gates and operating systems, we have made sure this vital structure can continue reducing flood-risk for the next 50 years.

This was a highly complex engineering project, delivered while the flood storage area remained operational. I would like to thank our partners, contractors, landowners and local communities for helping us complete it successfully.

Jamie Henderson, Kent County Council cabinet member for environment, coastal regeneration and public health, said:

Flooding can have a devastating impact on people’s homes, businesses and livelihoods, which is why investments like this are so important.

The expanded Leigh flood storage area and new Hildenborough defences will provide greater protection for communities across the Medway catchment and help safeguard hundreds of homes and businesses for years to come.

I am proud that Kent County Council has been able to support this project alongside our partners. Together, we have delivered a scheme that will make a real difference to local residents and strengthen the area’s resilience to flooding long into the future.

Cllr Matt Boughton, Leader of Tonbridge and Malling Borough Council, said:

Our borough is shaped by the beauty of the River Medway but over the years we’ve also seen the devastation to homes, businesses and communities caused by flooding. I’m proud that Tonbridge and Malling Borough Council has been able to invest half a million pounds in this major improvement to our flood defences.

We know it will result in greater protection and resilience for our residents, towns, villages and our local economy, defending our community from rising waters. This is the culmination of a complex engineering project that has already brought significant benefits to the area, through work and training opportunities and is testament to what good partnership working can achieve. For generations to come, this system will be helping to reduce the likelihood of severe flooding in Tonbridge, Hildenborough and other villages downstream.

Major engineering work at Leigh

The project team completed the work over 3 years while ensuring the flood storage area remained fully operational, protecting downstream communities.

New 12.5 tonne gates were installed. Each one was manufactured off-site in sections before being welded together on site and lifted into place with a 300 tonne crane. New lifting and electrical systems were put in place, and moving platforms built to ensure the structure could be maintained more easily.  And with an eye to helping nature an eel pass was constructed so that eels, a protected species, can navigate their way through.

New protection for Hildenborough

The expanded storage area works alongside new defences in Hildenborough, where a significant source of flood risk is the River Medway backing up into the Hawden Stream.

The Hildenborough scheme includes a 98-metre embankment across the floodplain, a new pumping station on the Hawden Stream, and a sheet-piled wall. Together, these measures prevent water from the River Medway backing up into Hildenborough without increasing flood risk elsewhere.

Approximately 180 Hildenborough homes affected by flooding in 2013, along with many others, will benefit directly from the new embankment and pumping station. Other properties will benefit from the additional capacity provided at Leigh.

Background:

Lasting benefits for local communities

During construction, the project generated more than £23.7 million in social-value benefits. This included 4,000 volunteer hours supporting environmental and community projects across Kent and Sussex.

Some 25 young people completed work experience on the project, 5 of whom subsequently joined VolkerStevin through its graduate apprentice programme. More than 20 people living within 15 miles of the project were also employed during its delivery.

The project contributed more than £10,000 in donations, materials and practical assistance to community organisations and charities. Environmental activities included stream clearance, habitat improvements, dormouse boxes made from recycled site timber, and the creation of habitats for small animals and insects at Haysden Country Park.

Check your flood risk

Flood defences can reduce the likelihood and impact of flooding, but they cannot eliminate the risk completely.

Residents are encouraged to check their flood risk, sign up for flood warnings and make a personal flood plan at: Get flood warnings by text, phone or email - GOV.UK

The Leigh flood storage area sits between Leigh and Penshurst on the River Medway. It consists of a 1.3-kilometre-long, 5-metre-high earth embankment and a control structure containing 3 steel gates.

During normal river conditions, water passes through the control structure. When flooding is forecast, the gates can be used to limit the flow and temporarily store water upstream, reducing peak river levels in downstream communities.

A trained Environment Agency operator is available 24 hours a day, 365 days a year to monitor catchment conditions and weather forecasts and operate the structure when properties are at risk.

The flood storage area is part of a wider flood-risk management system that includes the Tonbridge town walls and the natural floodplain at the sports pitches.

The scheme cost approximately £42 million to design and construct and will provide more than £155 million of benefits to downstream communities.

Funding comprised:

• £36,616,500 of Flood Defence Grant in Aid;
• £2,500,000 from Kent County Council;
• £2,298,500 from the South East Local Enterprise Partnership;
• £500,000 from Tonbridge and Malling Borough Council; and
• £85,000 in levy funding.

The project was delivered through partnership working involving the Environment Agency, Tonbridge and Malling Borough Council, Kent County Council and the Kent and Medway Economic Partnership.

Climate change is the biggest risk we face – we are experiencing wetter winters and drier summers, with increased likelihood of more intense rainfall leading to flooding.  

The last 12 months have seen extreme effects on our environment in rapid succession. This summer is on course to be the UK’s hottest on record. July 2026 was the driest July in both England and Wales since records began in 1836. Between April 2025 and March 2026, the UK experienced 7 named storms, including: Bram, Goretti and Chandra. 

Our national flood-risk assessment - NaFRA2 - published in 2024, shows that around 6.3 million homes and businesses in England are in areas at risk of flooding from one or a combination of sources: rivers, the sea, and surface water.