Vyrnwy Aqueduct Modernisation – Pipeline Renewal Works
Key Achievements
- Delivered over 10km+ of slip-lining works across multiple aqueduct sections
- Installed new 900mm polyethylene (PE) pipe with existing 42” cast iron mains
- Successfully completed 5,210m at Siphon 1 (Malpas)
- Delivered works across multiple locations in collaboration with Avove and OCU
- Maintained performance against Outcome Delivery Incentive (ODI) targets
- Supported the upgrade of critical infrastructure supplying water across the North West
Project Overview
GDB Civils Ltd. supported the modernisation of the historic Vyrnwy Aqueduct as part of United Utilities’ AMP7 investment programme.
Focus
The aqueduct, over 130 years old, transports drinking water from Lake Vyrnwy to homes and businesses across Cheshire, Merseyside, and the wider North West.
The works
The upgrade programme involves cleaning and relining three parallel pipelines to improve water quality, increase system resilience and ensure long term reliability of supply. GDB played a key role in delivering pipeline renewal works across multiple sections of the aqueduct, working in collaboration with principle contractors Avove Utilities and OCU.
Key Challenges
- Working on critical live water infrastructure
The aqueduct is a key support route, requiring careful planning and control during renewal works. - Large-scale pipeline installation
Slip-lining long sections of large-diameter pipe required precise coordination and execution. - Challenging ground and weather conditions
Works were carried out across varied terrain and in changing weather conditions - Multi-party coordination
Delivery required close collaboration with principal contractors and client teams across multiple locations - Programme and performance targets
Works were delivered against strict Outcome Delivery Incentive (ODI) deadlines
Our Delivery Approach
GDB delivered pipeline renewal works through a structured and collaborative approach across multiple aqueduct sections
Works included:
- Slip-lining new 900mm PE pipe into existing 42” cast iron mains
- Coordinating logistics and installation across multiple sites
- Supporting commissioning and transition between pipeline sections
Key sections delivered include:
- Siphon 1 (Malpas – Avove): 5,210m completed
- Siphon 2 (Runcorn – OCU): 1,500m completed, with a further 1,500m in commissioning
- Siphon 3 (Widnes – Avove): 3,588m completed, with additional sections in commissioning
The works required careful sequencing and coordination to maintain efficiency and minimise disruption across the wider programme.
Safety & Risk Management
All works were carried out in line with strict health, safety and water hygiene standards, reflecting the critical nature of the infrastructure.
Key measures include:
- Controlled installation processes for large-diameter pipeline slip-lining
- Compliance with water hygiene requirements for potable water infrastructure
- Ongoing coordination with principal contractors to ensure safe working practices
- Management of site conditions across multiple locations and environments
The project was delivered while maintaining high safety standards across all phases.
Outcome
(Ongoing Project)
GDB has successfully delivered significant sections of pipeline renewal works as part of the Vyrnwy Aqueduct Modernisation Project.
Key outcomes include:
- Completion of over 5km of slip-lining works at Siphon 1
- Ongoing delivery across Siphones 2 and 3
- Contribution to improve water quality and system reliability across the North West
The project demonstrates GDB’s ability to:
- Deliver large-scale infrastructure works
- Operate effectively across multiple sites and stakeholders
- Maintain quality and performance under demanding programme requirements
The modernisation programme continues to progress, supporting the long term resilience of the region’s water supply network.