Old Leake Distribution Zone Reinforcement Mains (2026)

Preparing for a section of open cut pipe installation - Courtesy of @one Alliance

Old Leake and Wrangle are rural Lincolnshire communities set within the low‑lying coastal plain east of Boston. The area features dispersed settlements, agricultural land, and an extensive network of drainage channels and waterways that shape both the landscape and the supporting infrastructure. Supplying reliable drinking water in this environment presents unique engineering challenges – demand can vary widely, pipe routes stretch across long rural corridors, and with limited alternative supply routes, maintaining network resilience is essential.

Old Leake Distribution Zone

The Old Leake Distribution Zone (DZ) played a vital role in supplying homes, farms, and local businesses across the area. Water is supplied via the North Boston Trunk Main, boosted at Haltoft End, and stored at Old Leake Water Tower, which regulates pressure across the network.

For many years the system operated reliably, however, changes to supply routes, ageing infrastructure, and increasing demand pressures had reduced network resilience, making the system more vulnerable during peak consumption periods.

Recognising the importance of securing long-term supply reliability for the community, Anglian Water commissioned Anglian Water’s @one Alliance to deliver a strategic reinforcement scheme to protect water services for over 1,300 properties.

The issue

In recent years, peak demand periods had exposed a supply-and-demand imbalance within the Old Leake Network. During times of high-water use, such as warm weather, irrigation demand, or simultaneous domestic consumption, the network struggled to maintain adequate pressure. This resulted in low pressure affecting up to 1,366 properties across Old Leake and Wrangle and increased the risk of temporary supply interruptions. While pressure typically recovered once demand reduced, the recurring nature of these events created a growing risk to service reliability and customer satisfaction.

Preparing for a section of open cut pipe installation – Courtesy of @one Alliance

Several factors contributed to the problem, including limited network capacity as the existing pipe diameters and flow capacity were insufficient to maintain pressure during peak demand.

Other contributing issues included restricted treated water storage, as storage at Old Leake Water Tower was not sufficient to buffer high demand events; ageing pipe materials, with sections of asbestos cement (AC) and cast iron (CI) mains experiencing a high burst frequency, particularly during demand surges; and reduced system resilience, as historically the network had benefited from additional supply routes, but damage to former supply mains had reduced redundancy, leaving the zone more vulnerable.

Because the low pressure only occurred during peak demand and not continuously, affected properties were not eligible for inclusion on the DG2 Register. Nevertheless, the situation posed operational risks, including potential ODI penalties for interruptions to supply and pressure failures. And without intervention, the frequency and severity of pressure issues were likely to increase over time.

Supply chain

The successful delivery of the Old Leake reinforcement scheme relies on the collaborative expertise of @one Alliance and its specialist supply chain partners, including:

• Client: Anglian Water
• Project delivery: @one Alliance
• Principal contractor: Balfour Beatty
• Horizontal directional drilling: Barhale
• HPPE water main: SIMONA Peak Pipe Systems Ltd
• Pressure control: i2O Water Ltd
• Pressure reducing valves: AVK UK Ltd
• Pressure reducing valves: Wolseley UK
• Bi-directional pressure relief valve: CLA-VAL UK Ltd
• Traffic management: Clancy Traffic Management (CTM)
• Road reinstatement: WN Surfacing Ltd

The solution

To address these challenges, Anglian Water’s @one Alliance are nearing completion a £3.2m reinforcement scheme designed to improve hydraulic capacity, stabilise pressure, and strengthen overall network resilience. At the core of the project was the installation of approximately 4.7km of new 225mm high-performance polyethylene (HPPE) water main, creating a stronger and more reliable supply route across the distribution zone.

To minimise disruption to residents and road users, most of the pipeline was installed using horizontal directional drilling to minimise excavation. This approach significantly reduced traffic disruption, reinstatement work, and the overall environmental impact.

(left) Start of a section of open cut works and (right) pipe installation underway – Courtesy of @one Alliance

Shorter sections were installed using open-cut methods where appropriate, including field crossings and limited road sections. A strengthened SDR11 pipe was used beneath the Hobhole Drain to ensure durability at this critical crossing point.

The new reinforcement main replaced ageing galvanised iron pipework and enabled the removal of sections of climate-vulnerable mains, improving long-term reliability and reducing the likelihood of future failures.

To maintain consistent pressure during high demand, the scheme incorporated modern pressure control and monitoring technology, including:

• Installation of pressure reducing valves (PRVs) to stabilise pressure.
• District metering and flow monitoring systems.
• Intelligent pressure control using i2O technology.
• Real-time telemetry for performance monitoring.
• Additional isolation valves to improve operational flexibility.

These smart systems enabled dynamic pressure management, allowing the network to respond in real time to changes in demand while reducing stress on infrastructure.

Targeted pipe replacements and new cross-connections were installed to improve how water could be routed around the local network. This allowed operators to redirect flows during peak demand, maintenance activities, or unexpected incidents, ensuring customers remained supplied at all times of the day.

Hydraulic modelling confirmed that the upgraded system would meet required flow demands without negatively affecting the wider distribution network.

The delivery approach prioritised sustainability alongside engineering performance, including extensive use of horizontal directional drilling to reduce excavation and reinstatement impacts, and efficient materials selection to improve durability and lifespan.

Construction methods contributed to a 64% reduction in embodied carbon compared with historic benchmarks. This project also aligned with Anglian Water’s commitment to delivering low-carbon infrastructure around the region, while improving resilience at the same time.

Traffic management in place – Courtesy of @one Alliance

Community impact

Clear communication and minimising disruption were key priorities throughout the project. Around 190 nearby customers received advance notification letters, supported by press releases, social media updates, and SMS reminders. Messages were tailored for residents close to construction areas, explaining what to expect; such as potential noise, site activity, and accurate timelines. Also, information boards were installed at the site compound so passers-by could easily understand the purpose of the works. Local parish councils were engaged early and kept informed throughout, ensuring community questions and concerns were listened to and addressed.

In addition to infrastructure improvements, the team sought to leave a positive local legacy. Some team members supported a volunteering initiative in Old Leake, working with the parish council and community groups to complete a litter pick in early 2026, filling 18 bags of litter on a road that was closed during our traffic management periods.

Works were carefully planned to minimise disruption to everyday life. No public rights of way or local bus routes were affected, businesses were contacted directly to coordinate access, and the main site compound was positioned on The Gride to further limit community impact.

This proactive approach ensured construction could progress safely while maintaining access and supporting normal local activity.

Teams members working with community groups to pick up litter – Courtesy of @one Alliance

Conclusion

The project is a vital investment in strengthening water supply resilience for the Lincolnshire communities of Old Leake and Wrangle. By installing a new reinforcement main, upgrading pressure management systems, and improving network flexibility, it has resolved long‑standing peak‑demand issues and significantly reduced the risk of low pressure and supply interruptions.

Beyond the improvements themselves, the project demonstrated the value of community engagement, educational outreach, and local volunteering in delivering infrastructure that benefited both customers and the wider community.

Set to complete in mid-2026, the upgraded network will provide more consistent water pressure during peak demand, reduced burst risk, improved reliability, smarter monitoring, and proactive network management. It will also enhance resilience during operational incidents and peak flows, with a lower carbon impact through the team’s project delivery and engineering methods.

Through innovative engineering, collaborative delivery, and meaningful community engagement, Anglian Water’s @one Alliance is strengthening essential infrastructure and helping secure a resilient water supply for future generations across this rural Lincolnshire community.