A320, North of Woking, Surrey

Flood Prevention

SDS stormwater infrastructure is critical to the completion of the A320 improvement scheme.

Overview

The A320 North of Woking improvement scheme is a £41.8m initiative to upgrade the main road between Ottershaw and Chertsey, enhancing traffic capacity, safety, and connectivity to local communities, including St Peter’s Hospital, while supporting planned housing growth under the Runnymede 2030 Local Plan. The project includes widened carriageways, new roundabouts, improved pedestrian and cycle routes, and flood mitigation measures to futureproof the transport corridor.

What We Did

SDS supplied and installed two GEOlight® attenuation tanks with capacities of 630m³ and 320m³, providing a total of 950m³ of below-ground stormwater storage beneath major junctions. The lightweight, modular tanks were delivered in pre-assembled blocks, enabling rapid installation within constrained road spaces and busy traffic environments. Manufactured from recycled PVC, the GEOlight® tanks aligned with sustainability objectives while ensuring long-term hydraulic performance and resilience to extreme rainfall.

Results

The GEOlight® systems now manage surface water runoff along the upgraded A320, maintaining pre-development discharge rates and reducing flood risk. By enabling safe construction of widened roads and junctions, the tanks support improved transport accessibility, protect critical infrastructure, and facilitate nearby housing development. The solution contributes to Surrey County Council’s vision for resilient, sustainable communities while ensuring minimal disruption during installation and long-term operational reliability.

SDS delivered its GEOlight® solution to support flood mitigation on this high-profile scheme. The system was designed to meet strict technical, sustainability, and installation requirements, ensuring long-term drainage performance across critical transport infrastructure. Our reliable delivery approach helped the project team remain on programme while achieving their flood resilience objectives.

– Ben White, Specification Manager, SDS

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