Redbridge Expands Underground Hydrorock Flood Defences in Redbridge 2026

Key Points

• Infrastructure Investment: Redbridge Council has expanded its flood defence infrastructure across three major areas in the borough as part of a wider £11 million flood risk management initiative.
• Innovative Technology: The council rolled out new stretches of Hydrorock—a Dutch-developed underground material that acts like a sponge—to absorb heavy rainfall and release it gradually into drainage networks.
• Targeted Locations: Installation took place in High Road (Seven Kings), Claybury Broadway (Clayhall), and Tomswood Hill (Barkingside), all identified as high-risk zones based on past flooding incidents.
• Paving Improvements: Underground installations were coupled with surface-level permeable paving resurfacing to enhance rainwater absorption directly from road surfaces.
• Expanded Capacity: The newly completed installations can hold up to 426,000 litres of storm water, bringing the total borough-wide flood storage capacity to 2.2 million litres.
• Wider Strategy: The underground roll-out follows the earlier completion of six rain gardens across Clayhall, Woodford, and Hainault.

Redbridge (East London Times) October 16, 2026 – Redbridge Council has expanded its network of underground flood defences across key risk zones within the borough to safeguard residential properties and local infrastructure from heavy rainfall. The town hall rolled out new installations of an innovative underground block system known as Hydrorock across High Road in Seven Kings, Claybury Broadway in Clayhall, and Tomswood Hill in Barkingside. The project forms a core part of the local authority’s ongoing £11 million flood risk mitigation initiative aimed at alleviating surface water pressure during severe weather events.

Where have the new flood defences been installed?

The recent expansion targets three specific locations within the borough that were identified as susceptible to surface water flooding based on historical flood patterns and drainage assessments. Engineers completed works along High Road in Seven Kings, Claybury Broadway in Clayhall, and Tomswood Hill in Barkingside.

To complement the subterranean drainage works, contractors resurfaced sections of the adjacent roads with permeable paving. This surface material allows surface water to filter directly through the road layer into the underlying Hydrorock blocks, reducing immediate surface runoff on busy carriageways.

How does the Hydrorock underground technology work?

Hydrorock, an ecological surface water management technology engineered in the Netherlands, functions as an underground sponge. Constructed from natural rockwool fibres, the subterranean blocks absorb high volumes of rainwater rapidly during intense downpours.

Once absorbed, the blocks retain the storm water temporarily in underground reserves. The system then discharges the collected water into the local sewer network at a controlled, gradual rate. By regulating the flow of rainwater into municipal drains, the system prevents sudden surges from overwhelming local drainage capacity, which is a primary cause of road and property flooding in urban areas.

What is the total storage capacity of the new flood defences?

The newly completed flood protection schemes installed across the three locations possess a combined temporary storage capacity of approximately 426,000 litres of storm water during severe weather events.

With these recent additions included, the cumulative storage capacity across the entire Redbridge borough flood defence network has reached approximately 2.2 million litres. This installation builds upon green infrastructure works completed earlier in the year, which included the construction of six rain gardens situated across Clayhall, Woodford, and Hainault.

What did local council leaders say about the development?

Jo Blackman, Cabinet Member for Environment at Redbridge Council, outlined the objective behind the expansion of the flood protection infrastructure across the borough. Blackman stated that the town hall is strengthening flood defences, reducing local flood risk, and helping build resilience as extreme weather becomes more common.

Background of the flood defence expansion project

Urban areas within the London Borough of Redbridge have experienced recurrent localized surface water flooding during periods of intense rainfall over past years. High density paving, concrete surface coverage, and aging drainage infrastructure in East London have historically created conditions where sudden storm water surges exceed the discharge rate of standard sewer systems.

In response to these climate resilience challenges, Redbridge Council allocated funding toward an overarching £11 million flood management strategy. The strategy combines sustainable drainage systems (SuDS)—such as roadside rain gardens—with subterranean technological solutions like Hydrorock. Prior to the current phase of development in Seven Kings, Clayhall, and Barkingside, the council implemented initial stages of the network, including natural drainage filtration beds and rain gardens designed to intercept surface runoff before it reaches primary road networks.

Prediction: How will this flood defence expansion affect local residents and businesses?

The completed expansion of the Hydrorock network directly impacts residents, business owners, and commuters across Seven Kings, Clayhall, and Barkingside by reducing the likelihood of surface water disruption during heavy rainfall.

For property owners residing in or adjacent to the affected zones on High Road, Claybury Broadway, and Tomswood Hill, the installation offers heightened protection against property inundation and associated water damage risks. Decreased flood risk typically stabilizes local property damage claims and reduces the potential for rising home insurance premiums in designated flood-prone postcodes.

For road users and local business operators, the combination of permeable paving and subterranean absorption blocks is anticipated to reduce road closures, standing water hazards, and traffic delays during intense storms. By holding up to 426,000 litres of runoff locally during heavy downpours, the infrastructure minimizes sewer surcharging, helping maintain access to local commercial thoroughfares and transport links across the borough.