New Drainage System and Flood Defence at The Navigation Inn, Enfield – Mitchells and Butlers

Project Snapshot

Client	Mitchells & Butlers
Sector	Hospitality
Location	The Navigation Inn, 4 Wharf Road, Enfield EN3 4XX
Services	Excavation, drainage installation, flood defence design, backflow prevention
Duration	2 months
Challenge	Repeated flood damage causing revenue loss and stock damage at a high-value pub estate site

Overview

The Navigation Inn is a large Mitchells & Butlers pub on the Enfield waterfront, a venue that holds significant commercial value within the group’s estate. It had been flooding repeatedly. Every time it happened, the pub lost revenue, stock was damaged, and the cleaning and remediation costs mounted. The root cause was structural: the drainage system simply wasn’t capable of handling the volume of surface water the site generated, and there was no defence against floodwater backing up from the adjacent canal.

Mitchells & Butlers commissioned LDF to design and install a complete commercial drainage and flood defence system for the site. The brief was straightforward: stop the flooding permanently.

The Challenge

The Navigation Inn’s flooding problem had two distinct causes. First, the existing drainage infrastructure was undersized and not configured to cope with the volume of surface water runoff the site produced, particularly during periods of heavy rainfall. Water had nowhere to go quickly enough and backed up across the site.

Second, the pub’s proximity to a canal created an additional risk: the potential for floodwater to enter the drainage system from the outside rather than just failing to exit it. This backflow risk required an independent engineering solution alongside any drainage upgrade.

The site also presented logistical challenges. The Navigation Inn is a working pub with a large outdoor area, car park, and significant footfall. Any drainage works would involve excavation across these areas, and the project had to be managed carefully to keep disruption to a minimum while the venue continued to trade.

Our Approach

LDF’s approach began with a full survey of the site to understand the existing drainage routes, the sources of surface water ingress, and the specific points at which floodwater was entering the premises.

From that survey, LDF designed a new drainage system engineered to handle the actual water volumes the site generates. This involved significant groundworks: excavation across the pub’s external areas to install new drainage runs, correctly sized and positioned to intercept surface water before it accumulated and caused problems.

Alongside the drainage installation, LDF designed and installed a flood defence system specifically addressing the canal backflow risk. This included the installation of backflow prevention devices within the new drainage infrastructure, ensuring that even in a high canal-level event, water could not re-enter the site through the drainage network.

Throughout the two-month project, LDF coordinated the phasing of works to protect as much of the trading operation as possible, minimising disruption to the pub’s operations and ensuring safe access across the site for customers and staff during excavation phases.

The Outcome

The Navigation Inn has not flooded since the new drainage and flood defence system was installed. The repeated cycle of remediation costs, stock losses, and revenue disruption has ended. The pub’s outdoor areas, car park, and cellar are protected by a system designed around the specific hydrology and flood risk of the site.

For Mitchells & Butlers, the outcome represents the protection of a significant asset. A venue of this size and location in the group’s estate represents a substantial investment, and the flood defence works ensure that investment is secure going forward.

About This Project Type

Commercial flood defence for hospitality sites requires a different approach to standard drainage maintenance. The challenge at The Navigation Inn wasn’t simply a blocked or undersized drain — it was a systemic failure of the site’s drainage capacity combined with an external flood risk from the adjacent canal. Resolving it required survey, design, groundworks, and specialist backflow prevention engineering, all delivered without closing the pub.

LDF works with hospitality operators across London and the South East on drainage design, installation, and flood defence for pub estate sites. For groups with multiple sites at flood risk, LDF can carry out multi-site surveys and deliver a coordinated programme of works.

Work with LDF

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