Successful Emergency Culvert Replacement at Pook Hill, Surrey

Monson Engineering provided civil engineering design consultancy services for the successful Design & Build culvert replacement project at Pook Hill, Chiddingfold, Surrey, delivered by CJ Thorne Civil Engineering on behalf of Ringway and Surrey County Council.

Following the partial collapse of a large-diameter concrete culvert beneath Pook Hill, emergency works were undertaken to excavate and replace the damaged section to a depth of approximately 3 metres, extending into adjacent private land.

Monson Engineering’s involvement included the detailed design of the replacement tailwall and culvert connection works, incorporating in-situ scour protection measures, as well as support for construction methodology, pollution control measures, and cross-sectional detailing.

Working collaboratively with the delivery team, Monson Engineering also helped develop practical value engineering solutions that improved buildability and reduced programme risk. The use of hessian bags filled with dry-mix concrete to form the headwall provided a flexible, lightweight, and highly adaptable construction solution while still achieving the required structural performance and embankment retention.

In addition, the adoption of Twinwall plastic pipes enabled easier handling and faster on-site installation, significantly accelerating construction, reducing operational risks, and lowering overall project costs.

The works were completed on programme and within budget, demonstrating the value of collaborative engineering, practical innovation, and site-led design solutions.