Natural flood management: introducing NFM to Barnet’s Friary Park

Building on earlier concept and detailed design work, Metis was appointed by the London Borough of Barnet to support the pre‑construction phases (including concept design, modelling and detailed design) and construction of a transformative Natural Flood Management (NFM) project in Friary Park.

Friary Park has long experienced surface water flooding, affecting both the park itself and residential areas along Torrington Park and Friary Close. The aim of this project was to reduce flood risk, enhance local biodiversity and deliver a more resilient green space. Metis acted as Principal Designer, Contract Administrator and technical engineering partner, ensuring the successful delivery of a new flood storage and treatment wetland alongside river naturalisation works on Blacketts Brook. These interventions form part of Barnet’s wider strategy to deliver Natural Flood Management solutions and climate‑resilient infrastructure.

The Challenge

Friary Park experiences regular flooding due to limited drainage capacity and the constrained nature of Blacketts Brook. Flooding had begun to affect nearby properties and the usable parts of the park, prompting Barnet to seek a robust, environmentally sensitive solution. This would be the first Natural Flood Management scheme in Barnet, addressing the flooding issue entirely as per NFM guidance.

The challenge included:

• Managing complex hydrology within a popular urban park
• Designing a wetland system capable of attenuating floodwaters while improving water quality
• Coordinating construction within a live public space
• Ensuring regulatory compliance under the CDM Regulations 2015
• Maintaining programme certainty throughout a 6-month construction window

Our Approach

Metis provided a comprehensive package of design assurance, safety management and construction-phase oversight.

Pre‑Construction Phase

Metis delivered:

• Principal Designer duties, including Designer Risk Assessments, the Pre‑Construction Information (PCI) pack, and the Health & Safety File
• Contract Administration support, including preparation and review of technical documentation and construction deliverables
• Kick-off, start‑up, and completion meetings to align client, contractor, and design teams

Construction Phase

During the six-month construction programme, Metis:

• Attended monthly progress meetings
• Provided regular Clerk of Works inspections to ensure compliance with design specifications and construction safety standards
• Managed contract obligations on Barnet’s behalf, including tracking time, resources, variations and cost
• Oversaw updates to the Health & Safety File and coordinated handover procedures
• Supported the contractor with design clarifications, minor drawing updates, and resolution of unforeseen issues on site

Additional Activities

As required, Metis also supplied:

• Engineering reviews and updates in response to design changes
• Additional site visits to monitor progress and resolve technical queries
• Significant drawings changes to fulfil additional requests from Greenspaces, the organisation owning the park and bearing responsibility for its management and maintenance

Outcomes

As of March 2026, there has been no flooding in the catchment since the Friary Park scheme was completed. The scheme represents a significant step forward in Barnet’s borough-wide SuDS strategy. With Metis’s specialist support, Barnet delivered:

• A new multifunctional wetland that provides flood attenuation, water-quality treatment, and habitat creation
• Naturalisation of Blacketts Brook, improving ecological value and park character
• Reduced flood risk to nearby homes along Torrington Park and Friary Close
• A scheme constructed in line with safety, environmental, and quality standards
• A robust Health & Safety File and contract documentation for long‑term asset management

This collaborative approach strengthened resilience within the local environment while enhancing the visitor experience at Friary Park. Metis also prepared the Management and Monitoring Plan for the park, and handed this over to Greenspaces as the basis for future maintenance of the scheme after construction. The Friends of Friary Park group have also expressed their satisfaction with the scheme.

Metis brings deep experience in natural flood management design, urban water management and construction-phase coordination for local authorities. Our ability to combine technical engineering expertise with proactive site leadership ensured Barnet’s aims were met efficiently and safely.

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