Protecting the Jubilee Channel: Emergency Action at Black Potts Weir

As part of the Environment Agency's Incident Response Contract in the Southeast (Hub C), Jacobs, in collaboration with BAM, led emergency works to stabilize Black Potts Weir. The effort protected the weir’s structural integrity, ensured continued operation of the Jubilee flood relief channel and safeguarded critical rail infrastructure.

The challenge: 

Black Potts Weir, the final structure on the Jubilee Channel (also known as the Maidenhead and Windsor Flood Alleviation Scheme), plays a vital role in reducing flood risk in the adjacent communities along the Thames. The weir is constructed beneath a railway viaduct and is considered essential infrastructure.

A 2020 dive survey revealed that downstream erosion protection had failed. Scour − moving water that removes material around a structure − was continuing around the weir foundation, posing a risk to its structural stability. Given the Jubilee Channel’s importance in managing flood flows, maintaining base flow through the weir was critical. The project faced several challenges:

• Accelerated timelines during the winter holiday period
• Difficult site access
• Construction in an active watercourse

The solution

Jacobs and BAM developed and implemented an accelerated program, mobilizing a fully integrated team in days. The team’s deep experience enabled fast, effective decision-making. Stakeholders included the Environment Agency, Jacobs, BAM, Mott MacDonald and Dalcour Maclaren.

Phase 1 – Immediate stabilization

• Installed sheet piles across the weir toe
• Grouted behind the piles to prevent further scour

Phase 2 – Long-term resilience

• Repaired the concrete weir apron
• Installed downstream armorstone protection

Jacobs used advanced Computational Fluid Dynamics (CFD) modeling to simulate water flow and scour under various conditions, optimizing the design. This collaborative and agile process allowed Jacobs and BAM to finalize design details quickly, meeting critical deadlines.

Key takeaways

1. Strong collaboration drives success: Close coordination between all stakeholders accelerated delivery and fostered innovation.
2. Agile decision-making enhances cost efficiency: Emergency contract delivery enabled rapid, cost-effective solutions.
3. Long-term solutions reduce future interventions: Shifting from temporary fixes to permanent solutions minimized future costs and interruptions.
4. Early engagement and clarity are critical: Involving all parties early and clearly defining project constraints were essential to the project’s success.