About the
project

RWP provided detailed design for the Friars Wash to Boxted trunk main replacement in Hertfordshire, upgrading critical clean water infrastructure to improve supply resilience in the St Albans area.
The Friars Wash to Boxted scheme involved the replacement of an ageing trunk main connecting Friars Wash and Boxted pump stations. The existing main had reached the end of its serviceable life and was presenting an increasing burst risk.
RWP’s design addressed the routing of the replacement main through a mix of highways, agricultural land and environmentally sensitive areas. The scheme required coordination with multiple stakeholders including Hertfordshire County Council, landowners and environmental bodies.
The design incorporated directional drilling for key crossings and open-cut installation for accessible sections, optimising construction methodology to suit the varied terrain.

Key Challenges
- Routing through environmentally sensitive areas.
- Highway crossings on busy routes near St Albans.
- Agricultural land access and reinstatement requirements.
- Coordination with multiple regulatory bodies.
- Maintaining supply during connection works.
Project Phases
- Route assessment and feasibility study.
- Environmental and planning coordination.
- Detailed pipeline and chamber design.
- Construction methodology development.
- Construction support and commissioning.
Achievements
- Replacement main delivered within programme.
- Environmental constraints successfully managed.
- Effective landowner and stakeholder engagement.
- No unplanned supply interruptions during connection.
- Improved supply resilience for the St Albans area.

Conclusion
- Early environmental assessment prevents planning delays.
- Flexible construction methodologies suit varied terrain.
- Stakeholder engagement is critical for cross-country routes.
The Friars Wash to Boxted project demonstrates RWP’s expertise in delivering trunk main replacements across varied terrain, balancing technical design with environmental and stakeholder considerations to improve clean water supply resilience.




